METHOD FOR PREPARING NANO-TITANATE, NANO-TITANIC ACID AND NANO-TIO2 CONTAINING EMBEDDED NANOPARTICLES AND METHOD FOR PREPARING METAL NANOPARTICLES

TECHNICAL FIELD

This application relates to nanomaterials, and more particularly to a method of preparing a nano-titanate, a nano-titanic acid and a nano-TiO₂containing embedded nanoparticles and a method of preparing metal nanoparticles. At the same time, the present invention also relates to a preparation method for metal nanoparticles.

BACKGROUND

At present, the main method for preparing nano-titanate, nano-titanic acid and nano-TiO₂is strong alkali hydrothermal method. However, this method requires the use of a high-pressure reaction vessel, and use amorphous nano-TiO₂and high-concentration strong alkali (e.g., NaOH solution) as raw materials, to obtain nano-titanate (e.g., nano-sodium titanate) through a long-term hydrothermal synthesis under high temperature conditions. Such nano-titanate can be generally neutralized and then obtain a titanate nanotube. For example, it was reported in 2001 that industrial anatase TiO₂and 10 mol/L NaOH solution were used as raw materials, and subjected to hydrothermal reaction in a high-pressure reaction vessel at 130° C. for 72 h, and then the product was washed until it was neutral. A titanate nanotube with a tube length of tens to hundreds of nanometers and an inner diameter of 5.3 nm was obtained. Other reported methods for preparing sodium titanate include: NaOH and TiO₂weighed according to the measurement relationship was put into a polytetrafluoroethylene high-pressure reactor and mixed. The mixture was kept at 230° C. for 48 h to 96 h, cooled to room temperature and taken out, followed by subjected to washing and drying to obtain nano-sodium titanate, which was further reacted with acid to obtain nano-titanic acid. It can be seen that the traditional strong alkali hydrothermal method has the following characteristics. 1) TiO₂is used as titanium raw material. 2) It is carried out in a high-pressure reaction vessel, which requires closed high-pressure conditions. 3) It is carried out at a relatively high temperature. 4) It requires a long reaction time. 5) The obtained product is generally tubular nano-titanate or tubular nano-titanic acid. These characteristics, especially the use of expensive nano-TiO₂as titanium raw material, require a high-pressure sealed environment and an extremely long reaction time, which can even be calculated in days. This seriously increases production consumption and reduces production efficiency, and also hinders the large-scale preparation and application of nano-titanate, nano-titanic acid, and nano-TiO₂.

Doping nanoparticles has an important impact on the functional applications of nano-titanate and nano-titanic acid. At present, the commonly used method for doping is to prepare nano-titanate, nano-titanic acid or nano-TiO₂, and then physically mix the dope nanoparticles mainly composed of doping elements prepared by other methods with nano-titanate, nano-titanic acid or nano-TiO₂. However, in this mechanical and physical way of mixing, the doped nanoparticles are mainly attached together through van der Waals forces, which may easily cause the doped nanoparticles to fall off, resulting in unstable performance. Therefore, it is necessary to embed and fix the nanoparticles that need to be doped into the nano-titanate, nano-titanic acid or nano-TiO₂matrix and improve the excellent performance of the composite material.

Due to special surface effects, quantum size effects, quantum tunneling effects, and Coulomb blocking effects, metal nanoparticles exhibit many unique properties that are different from traditional materials in optics, electricity, magnetism, catalysis, etc., and thus are widely used in optoelectronic devices, absorbing materials, high-efficiency catalysts and other fields. At present, the methods for preparing the metal nanoparticles are divided into solid phase methods, liquid phase methods and gas phase methods according to the state of matter. The solid phase methods mainly include mechanical crushing method, ultrasonic crushing method, thermal decomposition method, explosion method, etc. The liquid phase methods mainly include precipitation method, alkoxide method, carbonyl method, spray heat drying method, freeze drying method, electrolysis method, chemical coagulation method, etc. The gas phase methods mainly include gas phase reaction method, plasma method, high temperature plasma method, evaporation method, chemical vapor deposition method, etc. Although there are many methods for preparing the metal nanoparticles, each of the methods has certain limitations, and it is especially difficult to achieve large-scale mass production. Therefore, it is of great significance to develop new methods for preparing the metal nanoparticles which can be produced on a large scale.

SUMMARY

An object of the disclosure is to provide a method of preparing a nano-titanate, a nano-titanic acid and nano-TiO₂containing embedded nanoparticles and a method of preparing metal nanoparticles, so as to overcome the technical defects existing in the prior art. The present disclosure includes twenty-two aspects in sequence as follows.

In the first aspect, a method of preparing a titanate nanofilm material containing embedded A nanoparticles is provided, comprising:

step (1) providing an initial alloy; wherein the initial alloy comprises a T-type element, Ti and a A-group element, and the phase composition of the initial alloy mainly consists of a T-Ti intermetallic compound solidly dissolved with the A-group element; and the T-type element comprises at least one of Al and Zn, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Re, Os, Ir, Ag, Cu, Ni, Fe and Co, and when the A-group element comprises Ag, the atomic percentage content of Ag in the A-group element is less than 50%;

step (2) reacting the initial alloy with an alkali solution at a temperature of T₁during which a reaction interface advances inward from the surface of the initial alloy at an average rate of greater than 2 μm/min; and the initial alloy at the reaction interface undergoes nano-fragmentation through a hydrogen generation and T-removal reaction and simultaneously undergoes shape and composition reconfiguration to generate a solid flocculent product containing embedded A nanoparticles; wherein 60° C.≤T₁≤T_{f solution}, and T_{f solution}is a boiling point of the alkali solution participating in the reaction at atmospheric pressure; and

step (3) lowering the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system in the step (2) from T₁and collecting the solid flocculent product containing embedded A nanoparticles, i.e., obtaining the titanate nanofilm material containing embedded A nanoparticles; wherein the A nanoparticles comprise at least one of A nanoparticles and A-O nanoparticles.

Furthermore, the thin film material, macroscopically viewed in the form of a powder material, is microscopically observed to consist of a large number of two-dimensional thin films.

Furthermore, the thin film material, macroscopically viewed as a powder material, microscopically observed to be composed of a large number of monolithic two-dimensional thin films dispersed or entangled, the structure of which is completely different from that of the nanoporous structure formed by the conventional dealloying reaction. The nanoporous structure obtained by the conventional dealloying reaction consists of a three-dimensional network of ligaments connected to form a whole, and its overall appearance is basically the same as that of the initial alloy before the dealloying reaction;

Furthermore, the two-dimensional thin-film material means a material in which the smallest unit of the material (e.g., a monolithic film) has a large area and its dimension in the thickness direction is much smaller than the two-dimensional dimensions in the area direction, and its thickness does not exceed 10 nm.

Furthermore, “embedded” refers to a forming method of in-situ embedded generation, i.e., the embedded A nanoparticles are generated at the same time as the titanate nanofilm is generated, such that embedded A nanoparticles are combined with the titanate nanofilm through partial or complete embedding in a spatial position, and are embedded therein without relying on external addition or external mixing.

In step (1),

Furthermore, the T-type element comprises Al; and furthermore, the T-type element is Al.

Furthermore, the T-type element comprises Zn; and furthermore, the T-type element is Zn.

Furthermore, the T-type element comprises Al and Zn.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Re, Os, Ir, Ag, and Cu; and when the A-group element contains Ag, an atomic percentage content of Ag in the A-group element is less than 50%.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Re, Os, Ir, and Cu; and furthermore, the A-group element comprises least one of Au and Cu.

Furthermore, “solidly dissolved” comprises interstitial solidly dissolving and replacement solidly dissolving.

Furthermore, the T-Ti intermetallic compound solidly dissolved with the A-group element means that the A-group element exists in lattice gaps of the T-Ti intermetallic compound in a form of interstitial atoms, or the A-group element replaces a position of T atom or a position of Ti atom in a crystal lattice of the T-Ti intermetallic compound by replacing atoms.

Furthermore, T refers to the T-type element, which is an abbreviation of the T-type element; and T represents any one of Al, Zn, and AlZn, and wherein there is no limit to the ratio of Al to Zn in AlZn;

Furthermore, C_A/C_Tirepresents a molar ratio of the A-group element solidly dissolved in the T-Ti intermetallic compound to Ti in the initial alloy, and 0<C_A/C_Ti≤0.30; Furthermore, 0<C_A/C_Ti≤0.20; and furthermore, 0<C_A/C_Ti≤0.10.

Furthermore, the initial alloy is prepared by solidifying a melt containing the T-type element, Ti and the A-group element; and during the solidification of the alloy a solidification structure is formed containing T-Ti intermetallic compound; wherein the A-group element is mainly solidly dissolved in the T-Ti intermetallic compound.

Furthermore, the T-Ti intermetallic compound is equivalent to a Ti-T intermetallic compound.

Furthermore, the solidification rate of the initial alloy melt is 1 K/s to 10⁷K/s.

Furthermore, the phase composition of the initial alloy mainly consists of the T-Ti intermetallic compound solidly dissolved with the A-group element.

Furthermore, the T-Ti intermetallic compound comprises at least one of T₃Ti, T₂Ti, and TTi intermetallic compounds.

Furthermore, the T-Ti intermetallic compound comprises at least one of Al₃Ti, Al₂Ti, and AlTi intermetallic compounds.

Furthermore, the initial alloy comprises at least one of the T₃Ti, T₂Ti, and TTi intermetallic compounds solidly dissolved with the A-group element respectively.

Furthermore, the initial alloy comprises at least one of the Al₃Ti, Al₂Ti, and AlTi intermetallic compounds solidly dissolved with the A-group element respectively.

Furthermore, the initial alloy comprises one of the Al₃Ti, Al₂Ti, and AlTi intermetallic compounds solidly dissolved with the A-group element respectively.

Furthermore, the initial alloy is mainly composed of the Al₃Ti intermetallic compound solidly dissolved with the A-group element.

Furthermore, the initial alloy is mainly composed of the Al₂Ti intermetallic compound solidly dissolved with the A-group element.

Furthermore, the initial alloy is mainly composed of the AlTi intermetallic compound solidly dissolved with the A-group element.

Furthermore, an atomic percentage of T in the initial alloy is less than or equal to 75%.

Furthermore, the atomic percentage of T in the initial alloy is less than or equal to 70%.

Furthermore, the atomic percentage of Al in the initial alloy is less than or equal to 75%.

Furthermore, the atomic percentage of Al in the initial alloy is less than or equal to 70%.

Furthermore, the initial alloy does not comprise T phase.

Furthermore, the initial alloy does not comprise Al phase.

According to the Al—Ti phase diagram, when an atomic percentage of Al in the Al—Ti alloy exceeds 75%, an alloy solidification structure generally contains the Al phase; and when an atomic percentage of Al in an Al—Ti alloy is less than 75%, the alloy solidification structure generally does not contain the Al phase.

According to the phase diagram, an alloy containing TiAl₂can coexist with a TiAl phase or a TiAl₃phase, but cannot coexist with the Al phase, so the alloy containing TiAl₂cannot contain the Al phase.

Furthermore, the T-Ti intermetallic compound means that the phase composition of the intermetallic compound is a T-Ti intermetallic compound phase, i.e., an XRD phase analysis result of the T-Ti intermetallic compound is a T-Ti intermetallic compound, comprising T₃Ti, T₂Ti, and TTi intermetallic compound phase structures. At this time, in addition to T and Ti, the T-Ti intermetallic compound can also contain other elements, such as solidly dissolved A-group element.

Furthermore, since the T-Ti intermetallic compound has a relatively fixed element ratio relationship, a main component ratio of the initial alloy can be roughly obtained based on the determined composition of the T-Ti intermetallic compound, the composition of the A-group element, and the molar ratio of the A-group element to Ti.

For example, if Au is solidly dissolved in the Al₃Ti intermetallic compound and C_Au:C_Ti=0.04, an average composition of the initial alloy is roughly Al_74.258Ti_24.752Au_0.99.

Furthermore, the average size of any one dimension in the three-dimensional direction of the initial alloy shape is greater than 4 μm;

Furthermore, the average size of any one dimension in the three-dimensional direction of the initial alloy shape is greater than 10 μm;

Furthermore, the average size of any one dimension in the three-dimensional direction of the initial alloy shape is greater than 15 μm;

Furthermore, the initial alloy is in the form of a powder or a strip, and the powder particles or ribbons have a scale of less than 5 mm in at least one dimension in the three-dimensional direction;

Furthermore, the initial alloy powder particles or ribbons have a scale of less than 1 mm in at least one dimension in a three-dimensional direction;

Furthermore, the initial alloy powder particles or ribbons have a scale of less than 500 μm in at least one dimension in the three-dimensional direction;

As a preference, the initial alloy powder particles or ribbons have a scale of less than 200 μm in at least one dimension in the three-dimensional direction;

As a preference, the initial alloy powder particles or ribbons have a scale of less than 50 μm in at least one dimension in the three-dimensional direction;

Furthermore, when the initial alloy is in the form of a strip, it can be prepared by a method comprising the melt spinning method;

Furthermore, when the initial alloy is in the form of a powder, a larger initial alloy ingot can be prepared by a casting method, and then crushed into the initial alloy powder.

In step (2),

Furthermore, T refers to the T-type element, which is an abbreviation of the T-type element; and the T represents any one of Al, Zn, and AlZn, and wherein there is no limit to the ratio of Al to Zn in AlZn;

Furthermore, the hydrogen generation and T-removal reaction refers to a reaction in which when the initial alloy is reacted with an alkali solution at a temperature of T₁, T is dissolved by the alkali and becomes a salt and enters the solution, while releasing a hydrogen gas.

Furthermore, the alkali solution comprises at least one of NaOH, KOH, LiOH, RbOH, Ba(OH)₂, Ca(OH)₂, and Sr(OH)₂solutions.

Furthermore, a solvent in the alkaline solution contains water; and furthermore, the alkaline solution is water.

Furthermore, a concentration of alkali in the alkali solution is 5.1.025 mol/L.

Furthermore, the concentration of the alkali in the alkali solution is 5.1.015 mol/L.

Furthermore, the concentration of the alkali in the alkali solution is 7-15 mol/L;

Furthermore, the concentration of the alkali in the alkali solution is 7-12 mol/L; and furthermore, the concentration of the alkali in the alkali solution is 10-15 mol/L.

Furthermore, the concentration of the alkali refers to a concentration of OH⁻ in the alkal solution.

Furthermore, the alkali in the alkaline solution reacting with the initial alloy is an overdose, and the volume of the alkaline solution is more than 5 times the volume of the initial alloy, so that the reaction can be proceed all the time at a higher alkaline concentration; Furthermore, the volume of the alkali solution is more than 10 times the volume of the initial alloy; and furthermore, the volume of the alkali solution is more than 20 times the volume of the initial alloy.

Furthermore, the temperature at which the initial alloy reacts with the alkaline solution is the temperature of the alkaline solution;

Furthermore, under a certain alkaline concentration condition, the temperature T₁of the alkaline solution is sufficient to ensure that the reaction interface advances inwardly from the surface of the initial alloy at an average rate of not less than 2 μm/min during the hydrogen generation and T-removal process and that the initial alloy can be nano-fragmented by the hydrogen generation and T-removal during the reaction process; in other words, the temperature T₁and the concentration of the alkaline solution are determined by the reaction rate, reaction time and reaction effect of the hydrogen generation and T-removal reaction (since the reaction rate and the initial alloy size is determined, then the reaction time is determined; the reaction time for hydrogen generation and T-removal is determined when the generated gas can't be observed by the naked eye); therefore, when the value of the reaction rate is used to confine the reaction, the temperature T₁and the concentration of the alkaline solution are indirectly confined.

Furthermore, the average rate of 2 μm/min is the critical reaction rate at which the initial alloy can undergo nano-fragmentation via the hydrogen generation and T-removal reaction during the reaction process;

Furthermore, the occurrence of nano-fragmentation means that the initial alloy is fragmented by the hydrogen generation and T-removal process into a single intermediate or product with a scale of less than 500 nm in at least one dimension in a three-dimensional direction;

Furthermore, T₁≥60° C.;

Furthermore, the reaction of the initial alloy with the alkaline solution is carried out at ambient pressure or high pressure;

Furthermore, the reaction of the initial alloy with the alkaline solution is carried out in a closed vessel;

Under a closed vessel, high pressure is defined when the pressure inside the vessel exceeds one atmosphere; also, additional high pressure can be formed if the gases generated by the reaction inside the vessel cannot be discharged.

Furthermore, when the reaction is carried out in the closed vessel, the initial alloy and the alkaline solution are first placed separately in the closed vessel, and when the temperature of the alkaline solution reaches a set reaction temperature, the initial alloy is then contacted with the alkaline solution and the reaction starts.

Furthermore, the temperature of the alkaline solution may exceed its boiling point temperature at ambient pressure within the airtight container;

Furthermore, the reaction of the initial alloy with the hot alkaline solution is carried out at ambient pressure;

Furthermore, the ambient pressure, is the atmospheric ambient air pressure without the use of a closed container; furthermore, if the container is not tightly closed, although the pressure inside the container is slightly higher than the ambient pressure in a completely open environment, the pressure at this time also falls into the category of ambient pressure as it is also a non-closed environment.

Furthermore, the reaction is carried out in an atmospheric pressure environment, and atmospheric pressure generally refers to 1 standard atmospheric pressure, wherein the boiling point of the corresponding water is 100° C.; when there is an alkali dissolved in the water, the boiling temperature of the aqueous solution of the alkali is higher than 100° C. under 1 standard atmospheric pressure, and the higher the concentration of the alkali is, the higher the boiling point is. For example, the boiling point of T_{f solution}for the 5.1 mol/L sodium hydroxide aqueous solution is about 108° C.; the boiling point of T_{f solution}for the 7 mol/L sodium hydroxide aqueous solution is about 112° C.; the boiling point of T_{f solution}for the 10 mol/L sodium hydroxide aqueous solution is about 119° C.; the boiling point of T_{f solution}for the 12 mol/L sodium hydroxide aqueous solution is about 128° C.; the boiling point of T_{f solution}for the 15 mol/L sodium hydroxide aqueous solution is about 140° C.; the boiling point of T_{f solution}for the 17 mol/L sodium hydroxide aqueous solution is about 148° C.; the boiling point of T_{f solution}for the 20 mol/L sodium hydroxide aqueous solution is about 160° C.; the boiling point of T_{f solution}for the 25 mol/L sodium hydroxide aqueous solution is about 180° C.; The boiling point of T_{f solution}for the 10 mol/L potassium hydroxide aqueous solution is about 125° C.; the boiling point of T_{f solution}for the 12 mol/L potassium hydroxide aqueous solution is about 136° C.; the boiling point of T_{f solution}for the 15 mol/L potassium hydroxide aqueous solution is about 150° C.;

Furthermore, 60° C.≤T₁≤T_{f solution}, wherein the T_{f solution}is the boiling point temperature of the solution of the alkali involved in the reaction at ambient pressure; Furthermore, 66° C.≤T₁≤T_{f solution}; Furthermore, 71° C.≤T₁≤T_{f solution}; Furthermore, 76° C.≤T₁≤T_{f solution};

Furthermore, 81° C.≤T₁≤T_{f solution}; Furthermore, 86°≤C.≤T₁≤T_{f solution}; Furthermore, 91° C.≤T₁≤T_{f solution};

Furthermore, 96° C.≤T₁≤T_{f solution}; Furthermore, 100° C.≤T₁≤T_{f solution}; Furthermore, 100°≤C.≤T₁≤T_{f solution};

Furthermore, 101° C.≤T₁≤T_{f solution}; Furthermore, 105°≤C.≤T₁≤T_{f solution};

Furthermore, 101° C.≤T_{f solution}−5° C.≤T₁≤T_{f solution};

Furthermore, 101° C.≤T_{f solution}−2° C.≤T₁≤T_{f solution};

As a further preference, the temperature of the alkaline solution is T_{f solution}, i.e. T₁=T_{f solution};

Since the highest temperature to which the reaction solution can be heated at ambient pressure is its boiling point temperature (T_{f solution}), when the temperature reaches this temperature and continues to be heated, the temperature of the solution does not increase. Therefore, the boiling point temperature is the easiest, simplest, and most accurate to control. Moreover, the reaction time required for the boiling point temperature reaction under the same conditions is also shorter than that required for other temperatures below the boiling point, and the product yield and efficiency are also the highest;

Furthermore, when 60° C.≤T₁≤100° C., the alkaline solution includes KOH;

Furthermore, when 60° C.≤T₁≤100° C., the concentration of KOH in the alkaline solution is not less than 2 mol/L; at this time, other OH⁻ can be provided by other alkalines to ensure that the total OH⁻ concentration reaches 5.1 mol/L or more;

Furthermore, when 60° C.≤T₁≤100° C., the alkaline solution mainly includes an aqueous KOH solution;

Furthermore, when 60° C.≤T₁≤100° C., the alkaline solution is an aqueous KOH solution;

Since T elements (Al, Zn) are amphoteric metals, they can react with hydroxide in hot concentrated alkaline solution to become T salts and dissolve in the solution while releasing hydrogen vigorously; Therefore, T in the initial alloy can be removed through the reaction of T with the alkali solution. A remaining A-group element and Ti in the initial alloy can further interact with the alkali solution and simultaneously undergo a series of changes, comprising a diffusion rearrangement of Ti atoms and an interaction with the A-group element, hydrogen, oxygen, OH−, and cations in alkali, and be subjected to reconfiguration of shape and composition to form the titanate nanofilm containing embedded A nanoparticles.

Furthermore, the solid flocculent product containing embedded A nanoparticles is an aggregate composed of the titanate nanofilm containing embedded A nanoparticles in the subsequent step (3).

Furthermore, the reaction of the initial alloy with hot alkaline solution at 60° C.≤T₁≤T_{f solution}is important for the preparation of the product with a microscopic morphology of thin film. In one comparative example, when the initial TiAl₃intermetallic alloy powder solidly dissolved with Au is reacted with a NaOH solution of 10 mol/L and at 35° C. for 2 h at ambient pressure, the shape of the original initial alloy powder before and after the reaction is substantially unchanged, and it remains as the original crushed and angular powdery particles. It also does not generate a large number of monolithic two-dimensional film-like products in the microstructure, but generates nanoporous structure of titanate or titanium through the three-dimensional network connection, which maintains the similar microstructure to the original alloy powder, including the angular shape; the size of their particle size is comparable to the size of the initial alloy powder, mainly in several microns or tens of microns level. Thus, the reaction of the initial alloy with the alkaline solution occurring at a lower temperature or near room temperature is completely different from the reaction of the present invention occurring at 60° C.≤T₁≤T_{f solution}, especially in the high temperature range, and the morphology of the products is also completely different.

Specifically, when the reaction temperature is 60° C.≤T₁≤100° C., which is a low range of 60° C.≤T₁≤T_{f solution}, and the alkali solution is mainly composed of a NaOH aqueous solution, a yield of a target product of the titanate nanofilm containing embedded A nanoparticles is low. However, when the alkali solution contains KOH and a titanate nanofilm matrix containing embedded A nanoparticles contains a potassium titanate nanofilm matrix, a yield of the titanate nanofilm containing embedded A nanoparticles of the product can be greatly increased. For example, when the alkali solution mainly consists of KOH aqueous solution and the reaction temperature is 60° C., a yield of a target product of the potassium titanate nanofilm containing embedded A nanoparticles is not less than 50%; when the reaction temperature is 71° C., a yield of a target product of the potassium titanate nanofilm containing embedded A nanoparticles is not less than 65%; when the reaction temperature is 81° C., a yield of a target product of the potassium titanate nanofilm containing embedded A nanoparticles is not less than 75%; when the reaction temperature is 91° C., a yield of a target product of the potassium titanate nanofilm containing embedded A nanoparticles is not less than 85%; and when the reaction temperature is 96° C., a yield of a target product of the potassium titanate nanofilm containing embedded A nanoparticles is not less than 90%. When the reaction temperature is 100° C.≤T₁≤T_{f solution}, which is a high range of 60≤C.≤T₁≤T_{f solution}, regardless of the change in the type of alkali, the yield of the titanate nanofilm containing embedded A nanoparticles in the obtained product is high, and the morphology of the product is completely different from the shape of the original initial alloy powder particles or ribbons. For example, when the reaction temperature is higher than 101° C., a high yield of the titanate nanofilm containing embedded A nanoparticles can be obtained, which is generally 95%-100%. When the reaction temperature is the boiling point T_{f solution}of the alkali solution at atmospheric pressure, a higher yield of the titanate nanofilm containing embedded A nanoparticles can be obtained, which is generally 99%-100%.

In particular, when the reaction occurs at ambient pressure and at the boiling point temperature T_{f solution}of the alkaline solution, the solution composition of the reaction system has an obvious special change, which is manifested in the following: in the temperature interval below the boiling point temperature of the alkaline solution, the solvent mainly exists as liquid water; however, near or at the boiling point temperature, the solvent contains water that is undergoing a transformation from liquid to gas, in addition to the liquid water and the gaseous water produced by boiling. Moreover, due to the presence of reactants in solution and as formed nano-scale products, according to the principle of heterogeneous nucleation, it provides a large number of plasmas for boiling and evaporation, so that the reaction system is in a special environment of complete boiling and evaporation. In this special environment, the content and state of dissolved atmospheric gases (oxygen, nitrogen) in water are also extremely specific (because the large number of boiling water vapor, hydrogen generated by the reaction of T and alkalis, changes the saturation partial pressure conditions of dissolved gases in water). At the same time, the Ti-T intermetallic compounds with A-group element solid solution react with the concentrated alkaline, and a large amount of hydrogen generates in the T-removal process of the alloy. The violent expansion effect caused by the hydrogen generated within a short period of time will promote the nano-fragmentation and shape and composition reconfiguration of the initial alloy at the reaction interface, and the T salts dissolved in alkaline solutions also change the composition of the reacting solution system. The T salts dissolved in alkaline solutions also change the composition of the reaction solution system. All of these characteristics of solutions at boiling point temperatures provide a very specific reaction environment for the reaction. Under this special reaction environment condition, a special reaction process will occur. The initial alloy will undergo a nano-fragmentation and a shape and composition reconfiguration process with high efficiency, which makes it difficult to stabilize the three-dimensional network-like continuous nanoporous structure usually generated by the dealloying reaction at low- or room-temperature. And instead, this process can produce a flocculent solid product mainly composed of titanate nanofilm containing embedded A nanoparticles through a special process of nano-fragmentation and reconfiguration of shape and composition. This greatly reduces the time for preparing the target film-like product, while achieving a high yield of the titanate nanofilms containing embedded A nanoparticles. Moreover, due to a constant boiling point of a specific alkali solution, the temperature can be controlled extremely accurately, making the control of morphology and composition of the product extremely precise and simple.

Furthermore, since the process of “nano-fragmentation—shape and composition reconfiguration of product” described in step (2) occurs almost simultaneously with the reaction of “hydrogen generation and T-removal process”, the theoretical minimum time required for the product generation process described in step (2) is the time required for the initial alloy reaction interface to advance inward from the surface to complete the hydrogen generation and T-removal reaction, which can be determined by the end of hydrogen generation.

Furthermore, the hydrogen generation reaction is a vigorous hydrogen generation reaction;

Furthermore, the vigorous hydrogen generation and T-removal reaction means that the rate of advancement of the reaction interface of the hydrogen generation and T-removal reaction is sufficiently fast that the hydrogen evolved from the reaction interface is concentrated to be released in a very short period of time, thus behaving as a vigorous reaction process.

Furthermore, the degree of vigor of the hydrogen generation and T-removal reaction is related to the rate of reaction advancement of the reaction interface from the initial alloy surface inwardly per unit time, the higher the temperature of the alkaline solution, the faster the rate of advancement of the reaction interface is, and the more violent the reaction is.

Furthermore, the reaction interface advances inward from the initial alloy surface at an average rate greater than 4 μm/min.

Furthermore, the reaction interface advances inward from the initial alloy surface at an average rate greater than 7.5 μm/min.

Furthermore, the reaction interface advances inward from the initial alloy surface at an average rate greater than 17.5 μm/min.

Furthermore, when 60° C.<T₁≤100° C., the reaction interface advances inward from the initial alloy surface at an average rate greater than 2 μm/min.

Furthermore, when 100° C.<T₁≤T_{f solution}, the reaction interface advances inward from the initial alloy surface at an average rate greater than 20 μm/min.

For example, when the concentration of the alkali is 10 mol/L, during the reaction between the Au₁Ti₂₅Al₇₄initial alloy and the alkali solution, the reaction interface advances from the initial alloy surface inward at the following rate:

When 60° C.<T₁≤71° C., an average advancement rate of the reaction interface is about 2.5-4.0 μm/min.

When 71° C.<T₁≤81° C., an average advancement rate of the reaction interface is about 4.0-7.5 μm/min.

When 81° C.<T₁≤91° C., an average advancement rate of the reaction interface is about 7.5-17.5 μm/min.

When 91° C.<T₁≤100° C., an average advancement rate of the reaction interface is about 17.5-35 μm/min.

When 100° C.<T₁≤110° C., an average advancement rate of the reaction interface is about 35-60 μm/min.

When 110° C.<T₁≤120° C., an average advancement rate of the reaction interface is about 60-125 μm/min.

When 120° C.<T₁≤T_{f solution}, an average advancement rate of the reaction interface is greater than 120 μm/min.

Since T elements (Al, Zn) are amphoteric metals, their reaction with alkaline solutions near the boiling point temperature (which is higher than 100° C.) at ambient pressure is very rapid. In general, the reaction time for the complete removal of T elements from the initial alloy is related to the shape of the initial alloy. The smaller the initial alloy powder particles or the thinner the initial alloy ribbons, the shorter the time required for completion of the hydrogen generation and T-removal reactions; conversely, the longer the time required for the completion of the hydrogen generation and T-removal reactions.

Furthermore, ultrasound is applied during the hydrogen generation and T-removal to further enhance the nano-fragmentation effect and reaction rate by ultrasound treatment;

Furthermore, the frequency of the ultrasound is from 20 kHz to 10⁶kHz;

According to the average advancement rate of the reaction interface and the size of the initial alloy, the minimum reaction time required for the completion of the hydrogen generation and T-removal reactions can be calculated as t. For example, when the initial alloy is a strip with a thickness of d, and the average advancement rate of the reaction interface is v, taking into account the fact that the reaction interface advances from the upper and lower surfaces of the strip, t=0.5 d/v; similarly, when the initial alloy is a granular alloy with a diameter of d and the average advancement rate of the reaction interface is v, t=0.5 d/v.

In one embodiment, the initial alloy strip of TiAl₃intermetallic compound solid dissolved in Ag reacts with a NaOH solution of 10 mol/L and at a boiling temperature of about 119° C. The average advancement rate of the reactive interface of the initial alloy strip is about −120 μm/min, i.e., for a 40 μm-thick initial alloy strip, the hydrogen generation and Al-removal reactions can be finished in 10 s; for a 20 μm-thick initial alloy strip, the hydrogen generation and Al-removal reactions can be finished in 5 s; and even if the initial alloy balls of a grain size of 5 mm, the hydrogen generation and Al-removal reactions of the initial alloy balls can be finished in 21 min;

In one embodiment, a initial alloy strip comprised TiAl₃intermetallic compound and Au solid solution is reacted with a 10 mol/L NaOH solution at its boiling temperature (the boiling temperature of about 119° C.), and the average advancement rate of the reactive interface of the initial alloy strip is about −120 μm/min, i.e., for a 40 μm-thick initial alloy strip, the hydrogen generation and Al-removal reactions can be completed in 10 s; for a 20 μm-thick initial alloy strip, the hydrogen generation and Al-removal reactions can be completed in 5 s. Even for a 5 mm initial alloy ball, the hydrogen generation and Al-removal reactions can be completed in 21 min;

When the d is about 40 μm, the preparation of its corresponding initial alloy is extremely simple, and it can be easily prepared by the ordinary melt spinning method, and according to t=0.5 d/v, even if the average advancement rate of the reaction interface is 2.5 μm/min corresponding to the low-temperature interval of 60° C., the hydrogen generation and T-removal reactions can be completed in 8 min;

When the hydrogen generation and T-removal reaction is completed, the reaction system subsequently reaches equilibrium; at this time, continue to extend the holding time of the reaction system at the original reaction temperature can still ensure the stability of the product. Thus, when the reaction time of the initial alloy with the hot alkaline solution exceeds the minimum required time t for hydrogen generation and T-removal reaction, e.g. up to several hours, the corresponding product can still be obtained;

Furthermore, the minimum reaction time of the initial alloy with the alkaline solution at temperature T₁is 10 s;

Furthermore, the reaction time of the initial alloy with the hot alkaline solution at Ti temperature is 10 s˜59 min;

Furthermore, the reaction time of the initial alloy with the hot alkaline solution at Ti temperature is 10 s˜29 min;

Furthermore, the reaction time of the initial alloy with the hot alkaline solution at Ti temperature is 10 s˜9.9 min;

Furthermore, the reaction time of the initial alloy with the hot alkaline solution at Ti temperature is 10 s˜4.9 min;

Furthermore, the reaction time of the initial alloy with the hot alkaline solution at Ti temperature is 10 s˜2 min;

Furthermore, the reaction time of the initial alloy with the hot alkaline solution at Ti temperature is 10 s˜1 min;

Furthermore, the reaction time of the initial alloy with the hot alkaline solution at Ti temperature is 10 s˜30 s;

Obviously, when T₁is higher and the initial alloy is thinner or the particle size is smaller, the shorter the reaction time required; conversely, the longer the reaction time;

Furthermore, the nano-fragmentation means that the initial alloy at the reaction interface is fragmented into a nano-scale intermediate or product through the hydrogen generation and T-removal reaction, and simultaneously subjected to reconfiguration of shape and composition to generate a two-dimensional titanate nanofilm containing embedded A nanoparticles. In this process, the hydrogen released violently by the hydrogen generation and T-removal reactions promotes the nano-fragmentation of the intermediates and products, the shape and composition reconfiguration of the products, and the diffusion distribution of the products in the alkaline solution after leaving the reaction interface.

Furthermore, the nano-fragmentation means that the initial alloy at the reaction interface is fragmented through the hydrogen generation and T-removal reaction into a single intermediate product or products having a scale of less than 500 nm in at least one dimension in the three-dimensional direction;

Furthermore, the solid flocculent product containing embedded A nanoparticles is mainly composed of a single intermediate product products having a scale of less than 20 nm in at least one dimension in the three-dimensional direction;

Furthermore, the solid flocculent product containing embedded A nanoparticles is mainly composed of a single intermediate product or product having a scale of less than 10 nm in at least one dimension in a three-dimensional direction;

Furthermore, the solid flocculent product containing embedded A nanoparticles, after being generated by shape and composition reconfiguration, does not remain at the initial alloy reaction interface, but leaves the initial alloy reaction interface by diffusion during generation and is further diffused and distributed in the alkaline solution by thermal diffusion and convection of the alkaline solution liquid;

Furthermore, the shape and compositional reconfiguration means that the hydrogen generation and T-removal reactions of the initial alloy and the intermediate product after nano-fragmentation undergo further shape and compositional changes simultaneously, generating a nano-sized product with a completely different composition and shape from that of the initial alloy on the micrometer or millimeter scale; the dimensions of the nanoscale product are described in the subsequent description of step (3).

Furthermore, the as-prepared titanate nanofilm containing embedded A nanoparticles do not contain a three-dimensional continuous network-like nanoporous structure or a porous skeletal structure;

Furthermore, the hydrogen generation and T-removal reactions transforms the micrometer or even millimeter-sized initial alloy into a large number of two-dimensional titanate nanofilms containing embedded A nanoparticles through a step-by-step nano-fragmentation process from the surface inwards;

Furthermore, the solid flocculent product containing embedded A nanoparticles mainly consists of a large number of two-dimensional titanate nanofilms containing embedded A nanoparticles combined by aggregation and entanglement with each other; which macroscopically appears as a solid flocculent product;

Furthermore, the flocculent solid-state product means that the nanoscale scale thin film-like product is in the form of a solid-state flocculant after agglomeration during diffusion, and can be suspended in solution for a longer period of time from an observational point of view.

Furthermore, the embedded A nanoparticles are different from ordinary reported nanoparticles which are mainly adsorbed by van der Waals forces (nanoparticles adsorbed by van der Waals forces can move and fall off), which can ensure that the embedded A nanoparticles can be embedded closely with the titanate nanofilm (cannot move or fall off). Since the embedded A nanoparticles are distributed in an island shape and cannot be connected due to a spatial hindrance of the titanate nanofilm matrix, it is difficult for the embedded A nanoparticles to continue to merge and grow. Therefore, as long as the titanate nanofilm matrix exists, the particle size of the embedded A nanoparticles can remain approximately unchanged during subsequent heating.

Furthermore, the embedded A nanoparticles exist in the titanate nanofilm in an embedded manner.

Furthermore, the component composition of the embedded A nanoparticles comprises at least one of the A-group element and an oxide of the A-group element.

In the step (3),

In general, after the temperature and products of a chemical reaction have reached equilibrium, if the temperature of the reaction system is slowly lowered, holding the reaction at the new temperature for a long time leads to a disruption of the original reaction equilibrium, with potential changes in the composition and morphologies of the reaction products.

The reaction system described in step (2) comprises the product generated by the reaction and the alkaline solution after the reaction;

In order to maintain the product of the initial reaction equilibrium in the hot alkaline solution while facilitating solid-liquid separation of the product, step (3) comprises a process of lowering the temperature of the solid flocculent product in the reaction system described in step (2) from T₁to a lower temperature interval. By controlling the rate of temperature reduction, the composition and morphology of the products formed at 60° C.<T₁temperature, in particular the temperature interval of 100° C.≤T₁, can be maintained by rapidly reducing the temperature of the reaction system, which makes it difficult for the reaction products to undergo corresponding changes in time.

Furthermore, the composition and morphology of the products formed at 60° C.≤T₁≤T_{f solution}temperature, in particular the temperature interval of 100° C.≤T₁≤T_{f solution}, can be maintained.

Furthermore, at atmospheric pressure, the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system in step (2) is reduced from Ti to the lower temperature range; wherein 60° C.≤T≤T_{f solution}.

Furthermore, 66° C.≤T₁≤T_{f solution}; Furthermore, 71° C.≤T₁≤T_{f solution}; Furthermore, 76° C.≤T₁≤T_{f solution}; Furthermore, 81° C.≤T₁≤T_{f solution}; Furthermore, 86° C.≤T₁≤T_{f solution}; Furthermore, 91° C.≤T₁≤T_{f solution};

Furthermore, 96° C.≤T₁≤T_{f solution}; Furthermore, 100° C.≤T₁≤T_{f solution}; Furthermore, 100° C.≤T₁≤T_{f solution};

Furthermore, 101° C.≤T₁≤T_{f solution}; Furthermore, 105° C.≤T₁≤T_{f solution};

Furthermore, 101° C.≤T_{f solution}−5° C.≤T₁≤T_{f solution};

Furthermore, 101° C.≤T_{f solution}−2° C.≤T₁≤T_{f solution};

Furthermore, T₁=T_{f solution};

Furthermore, the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system in step (2) is reduced from Ti to below 45° C.

Furthermore, the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system in step (2) is reduced from Ti to below 35° C.

Furthermore, the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system in step (2) is reduced from Ti to below 30° C.

Furthermore, the cooling rate of reducing the temperature of the solid product containing embedded A nanoparticles in the reaction system in step (2) is greater than 5 K/s.

Furthermore, the cooling rate is greater than 10 K/s.

Furthermore, the cooling rate is greater than 20 K/s.

Furthermore, the cooling rate is greater than 50 K/s.

Furthermore, the time required to reduce the temperature of the solid product containing embedded A nanoparticles in the reaction system in step (2) is less than 20 s.

Furthermore, the time required to reduce the temperature is less than 10 s.

Furthermore, the time required to reduce the temperature is less than 5 s.

Furthermore, the time required to reduce the temperature is less than 2 s.

It can be understood that when the temperature range of the reaction is a high range of 60° C.≤T₁≤T_{f solution}, such as 100° C.≤T₁≤T_{f solution}or T_{f solution}, rapidly lowering the temperature of the reaction product through step (3) ensure the stability of the composition and morphology of the product.

Furthermore, the method of lowering the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system in step (2) includes at least one of the following: adding solvent to dilute, filtering and cooling;

At atmospheric pressure, the reaction is carried out in an open container, such that the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system in step (2) can be easily reduced by adding a cold solvent (such as water) to the reaction system, and the alkali solution in the reaction system can be simultaneously diluted. As another approach, the hot alkali solution in the reaction system and the solid flocculent product containing embedded A nanoparticles can also be poured out rapidly and subjected to filtering and separating simultaneously, thereby rapidly reducing the temperature of the solid flocculent product containing embedded A nanoparticles.

Furthermore, the solvent corresponding to adding solvent to dilute the alkali solution contains water.

Furthermore, the temperature of the solvent corresponding to adding solvent to dilute the alkali solution is room temperature.

Furthermore, the temperature of the solvent corresponding to adding solvent to dilute the alkali solution is 0-30° C.

Furthermore, the temperature of the solvent corresponding to adding solvent to dilute the alkali solution is 0-25° C.

Furthermore, the temperature of the solvent corresponding to adding solvent to dilute the alkali solution is 0-20° C.

Furthermore, when the additive solvent for dilution is used, the temperature of the solid flocculent product containing embedded A nanoparticles in the reaction system described in step (2) is reduced while the temperature of the alkaline solution is simultaneously reduced, and in addition the concentration of the alkaline solution in the reaction system described in step (2) is reduced;

Furthermore, the concentration of the alkali solution after diluting is less than 0.25 times the original concentration; meanwhile, the temperature of the alkali solution after reducing the temperature is lower than 50° C.

Furthermore, the concentration of the alkali solution after diluting is less than 0.1 times the original concentration; meanwhile, the temperature of the alkali solution after reducing the temperature is lower than 45° C.

Furthermore, when filter cooling is taken to reduce the temperature, the specific steps are as follows: under atmospheric pressure, the solid flocculent product containing embedded A nanoparticles and the alkaline solution at a temperature of 60° C.≤T₁≤T_{f solution}is poured on a cold filter, and the solid flocculent product containing embedded A nanoparticles and the alkaline solution are separated by the filter; the heat of the solid flocculent product containing embedded A nanoparticles is rapidly conducted away by the environment and the filter, and the temperature of the solid flocculent product containing embedded A nanoparticles can be rapidly reduced to the low temperature range; Furthermore, 101° C.≤T₁≤T_{f solution}; and furthermore, T₁=T_{f solution}.

Furthermore, the temperature of the filter is 30° C. or less;

Furthermore, the temperature of the filter is 20° C. or less; and furthermore, the temperature of the filter is 10° C. or less.

Furthermore, the filter mesh plane is at an angle to the horizontal plane, so that after the hot alkaline solution including the solid flocculent product is poured into the filter mesh, it can be sufficiently filtered and cooled while flowing and spreading on the filter mesh;

Furthermore, the angle between the plane of the filter mesh and the horizontal plane is 15° to 75°;

Furthermore, the mesh aperture size of the filter mesh ranges from 5 μm to 1 mm;

Furthermore, the filter mesh includes a multi-layer filter mesh;

Furthermore, the filter mesh includes at least 4 layers;

Furthermore, the filter mesh includes a multi-layer filter mesh and the mesh pore size of each layer is inconsistent;

The solid flocculent products containing embedded A nanoparticles are generally aggregated and entangled together to form a larger aggregation group, so they can be firstly separated by the filter mesh with a larger aperture; by means of a multi-layer filter mesh, primary separation of the solid products can be achieved by a larger mesh filter, continued separation of the solid flocculent products can be achieved by the medium-sized mesh filter, and final separation of the solid flocculent products can be achieved by the small mesh filter;

Furthermore, the filter comprises a metal filter with excellent thermal conductivity.

It can be understood that when cooling down the temperature by cold mesh filtration, not only the temperature of the solid flocculent product containing embedded A nanoparticles is rapidly reduced, but also the separation of solid-liquid substances corresponding to the original reaction equilibrium occurs, which reduces the volume of the separated by-product solution as compared to the dilution method, and further ensures that the composition and morphology of the product generated by the T₁temperature are preserved, which is of positive significance.

Furthermore, as long as the temperature of the ultimately obtained titanate nanofilm material containing embedded A nanoparticle is lower than T₁, or it is subjected to solid-liquid separation, cleaning, preservation, and use at a temperature lower than T₁, regardless of the historical change of the temperature of the titanate nanofilm material containing embedded A nanoparticle in the intermediate process, it is part of the operation of reducing the temperature of the solid flocculent product containing embedded A nanoparticle in the reaction system according to step (2) from as described in step (2);

Furthermore, the process of collecting the solid flocculent product containing embedded A nanoparticles includes solid-liquid separation, washing, and drying of the solid flocculent product containing E-group elements;

Furthermore, the process of collecting the solid flocculent product containing embedded A nanoparticles means that the two-dimensional titanate nanofilm material containing embedded A nanoparticles is obtained.

Furthermore, the process of collecting the solid flocculent product containing embedded A nanoparticles means that a two-dimensional titanate nanofilm powder material containing embedded A nanoparticles is obtained.

Furthermore, the thin film material, macroscopically viewed in the form of a powder material, is microscopically observed to consist of a large number of two-dimensional thin films.

Furthermore, the embedded A nanoparticles mainly exist in the two-dimensional titanate nanofilm in an embedded manner.

Furthermore, the volume partially embedded in the two-dimensional titanate nanofilm, the embedded A nanoparticles also comprise an exposed volume which is not embedded in the nanofilm.

It can be understood that because the embedded A nanoparticles are generated in-situ and distributed in the two-dimensional titanate nanofilm, and since the nanofilm is thin enough, some of the embedded A nanoparticles will still have a volume partially exposed outside the nanofilm.

Furthermore, the embedded A nanoparticles are different from ordinary reported nanoparticles which are mainly adsorbed by van der Waals forces (nanoparticles adsorbed by van der Waals forces can move and fall off), which can ensure that the embedded A nanoparticles can be embedded closely with the titanate nanofilm (cannot move or fall off). Since the embedded A nanoparticles are distributed in an island shape and cannot be connected due to a spatial hindrance of the titanate nanofilm matrix, it is difficult for the embedded A nanoparticles to continue to merge and grow. Therefore, a particle size of the embedded A nanoparticles can remain approximately unchanged during subsequent heating.

Furthermore, the thickness of the titanate nanofilm containing embedded A nanoparticles is 0.25-7 nm.

Furthermore, the thickness of the titanate nanofilm containing embedded A nanoparticles is 0.25-4 nm.

Furthermore, the thickness of the titanate nanofilm containing embedded A nanoparticles is 0.25-3 nm.

Furthermore, the average area of the titanate nanofilm containing embedded A nanoparticles is greater than 500 nm².

Furthermore, the average area of the titanate nanofilm containing embedded A nanoparticles is greater than 5000 nm².

Furthermore, the average area of the titanate nanofilm containing embedded A nanoparticles is greater than 20,000 nm².

Furthermore, the cationic element in the titanate nanofilm is derived from the corresponding cationic element in the alkali.

Furthermore, titanate nanofilm containing embedded A nanoparticles is mainly low-crystallinity titanate.

Furthermore, the chemical composition of the titanate nanofilm containing embedded A nanoparticles comprises the A-group element, Ti, O, and the corresponding cationic element in the alkali; wherein the molar ratio of the A-group element to Ti satisfies 0<C_A/C_Ti≤0.30. For example, when the alkali is NaOH, the corresponding cationic element in the alkali is Na, then the chemical composition of the titanate nanofilm containing embedded A nanoparticles comprises the A-group element, Ti, O, and Na.

Furthermore, 0<C_A/C_Ti≤0.20; and furthermore, 0<C_A/C_Ti≤0.10.

Furthermore, the A nanoparticles are nanoparticles mainly composed of the A-group element.

Furthermore, the A-O nanoparticles are oxide nanoparticles mainly formed by a combination of the A-group element and O.

Furthermore, the A-O nanoparticles formed by the combination of the A-group element with different valences and O.

Furthermore, depending on different composition of the A-group element in the initial alloy, the composition of the embedded A nanoparticles will also be different. Since OH⁻ and O₂dissolved in the alkali solution can also participate in an oxidation reaction of an easily oxidized A-group element, when the A-group element comprises an easily oxidized element, the A nanoparticles comprise A-O nanoparticles formed by the combination of the A-group element and O.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized, comprising Au, Pt, Pd, Ru, Rh, Os, Ir, Ag or a combination thereof, embedded A nanoparticles in a prepared titanate nanofilm containing embedded A nanoparticles are also mainly composed of the A-group element, and the A-O content formed by the combination of the A-group element and O in the embedded A nanoparticles will be at a lower content. For example, when the A-group element is mainly composed of Au, Pt and Pd, the embedded A nanoparticles are mainly composed of Au—Pt—Pd nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are easily oxidized, comprising Cu, Ni, Fe, Co or a combination thereof, the composition of the embedded A nanoparticles in the prepared titanate nanofilm containing embedded A nanoparticles mainly comprises A-O nanoparticles formed by the combination of the A-group element and O. For example, when the A-group element is mainly composed of Cu and Fe, the composition of the embedded A nanoparticles in the titanate nanofilm containing embedded A nanoparticles mainly comprises Cu—O nanoparticles and Fe—O nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are not easily oxidized is high, the elements which are easily oxidized can be solidly dissolved in the elements which are not easily oxidized and are protected from oxidation, and the embedded A nanoparticles are mainly composed of nanoparticles containing the A-group element. For example, when the A-group element comprises Au and Cu, and a content of Au far exceeds that of Cu, the embedded A nanoparticles are mainly composed of Au(Cu) nanoparticles, in which Cu is solidly dissolved in the Au(Cu) nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are easily oxidized is high, the embedded A nanoparticles can contain the elements which are not easily oxidized and the elements which are easily oxidized simultaneously. For example, when the A-group element comprises Au and Cu, and a content of Cu far exceeds that of Au, the embedded A nanoparticles are mainly composed of Au—Cu nanoparticles and Cu—O nanoparticles.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Re, Os, Ir, Ag, Cu, Ni, Fe and Co, and when the A-group element contains Ag, the atomic percentage content of Ag in A is less than 50%.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Os, Ir and Cu.

Furthermore, the A-group element comprises at least one of Au and Cu.

Furthermore, the particle size of the embedded A nanoparticles is 1.0˜30 nm.

Furthermore, the particle size of the embedded A nanoparticles is 1.0˜20 nm.

Furthermore, the particle size of the embedded A nanoparticles is 1.0˜10 nm.

Furthermore, a yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in a final product is a weight percentage of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product.

Furthermore, the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product is 50%-100%.

Furthermore, the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product is 65%-100%.

Furthermore, the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product is 75%-100%.

Furthermore, the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product is 85%-100%.

Furthermore, the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product is 90%-100%.

Furthermore, the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product is 95%-100%.

Furthermore, the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles in the final product is 99%-100%.

In the second aspect, a method of preparing a titanic acid nanofilm material containing embedded A nanoparticles is provided, comprising:

reacting the product prepared according to the first aspect or the titanate nanofilm material containing embedded A nanoparticles prepared according to the first aspect with an acid solution, and collecting the solid product, i.e., obtaining the titanic acid nanofilm material containing embedded A nanoparticles.

By reacting with the acid solution, the residual alkali adsorbed on the surface of the titanate nanofilm material containing embedded A nanoparticles is firstly neutralized, and then ion exchange occurs between the cations in the titanate nanofilm material and hydrogen ions in the acid solution, thereby obtaining the titanic acid nanofilm material containing embedded A nanoparticles.

Furthermore, the acid solution contains at least one of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid, oxalic acid, picric acid, oleic acid and perchloric acid.

Since the two-dimensional titanate nanofilm containing embedded A nanoparticles or the two-dimensional titanic acid nanofilm containing embedded A nanoparticles prepared by this method is extremely thin, when the concentration of the acid is higher than 0.1 mol/L, obvious further dissolution of a two-dimensional titanic acid nanofilm matrix containing embedded A nanoparticles in the acid solution will occur. Moreover, when the embedded A nanoparticles contain oxides, the acid with a higher concentration will also react with the embedded A-O nano particles. Therefore, in order to prevent further reaction and dissolution of the two-dimensional titanic acid nanofilm matrix containing embedded A nanoparticles with the acid, a concentration of hydrogen ions in the acid solution is lower than 0.1 mol/L.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.09 mol/L.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.05 mol/L.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.01 mol/L.

Furthermore, the step of reacting the titanate nanofilm material containing embedded A nanoparticles with the acid solution comprises: 1) when the embedded A nanoparticles contain A-O nanoparticles, dispersing the titanate nanofilm material containing embedded A nanoparticles in water, gradually adding the acid solution in the mixed solution with constant stirring, so as to make pH of the mixed solution continuously reduce and ultimately maintain between 3-5; and after 1 min to 5 h, subjecting the mixed solution to separation, washing and drying, so as to obtain the titanic acid nanofilm material containing embedded A nanoparticles. When the pH is controlled to be maintained between 3-5, i.e., the corresponding concentration of the hydrogen ions in the mixed solution is 0.00001.0˜0.001 mol/L, it can be ensured that the residual alkali adsorbed on a surface of the two-dimensional titanate nanofilm material containing embedded A nanoparticles during the whole process is firstly neutralized, and then ion exchange occurs between the cations in the two-dimensional titanate nanofilm material containing embedded A nanoparticles and the hydrogen ions in the acid solution, thereby obtaining the two-dimensional titanic acid nanofilm material containing embedded A nanoparticles which is not reacted significantly with the acid solution. 2) When the embedded A nanoparticles do not contain A-O nanoparticles, the titanate nanofilm material containing embedded A nanoparticles is dispersed in water, and under stirring, the acid solution is gradually added thereto to make the pH value of the mixed solution decrease continuously and ultimately the PH value of the mixed solution is controlled to be maintained between 2 and 5, and after 1 min to 5 h, separation, cleaning, and drying are carried out to obtain the titanic acid nanofilm containing embedded A nanoparticles.

Furthermore, the two-dimensional titanic acid nanofilm containing embedded A nanoparticles has a thickness of 0.25 nm˜7 nm;

Furthermore, the two-dimensional titanic acid nanofilm containing embedded A nanoparticles has a thickness of 0.25 nm˜4 nm;

Preferably, the two-dimensional titanic acid nanofilm containing embedded A nanoparticles has a thickness of 0.25 nm˜3 nm;

Furthermore, the 2D titanic acid nanofilm containing embedded A nanoparticles has an average area greater than 500 nm²; as a preference, the 2D titanic acid nanofilm containing embedded A nanoparticles has an average area greater than 5000 nm²; as a further preference, the 2D titanic acid nanofilm containing embedded A nanoparticles has an average area greater than 20000 nm²;

Furthermore, the titanic acid containing embedded A nanoparticles is predominantly low crystallinity titanic acid;

Furthermore, the main chemical composition of the two-dimensional titanic acid nanofilm material containing embedded A nanoparticles comprises A-group element, Ti, H, and O; wherein the molar ratio of A-group element to Ti satisfies 0<C_A/C_Ti≤0.30;

Furthermore, 0<C_A/C_Ti≤0.20; Furthermore, 0<C_A/C_Ti≤0.10;

Furthermore, the particle size of the embedded A nanoparticles ranges from 1.0 nm to 30 nm;

Furthermore, the particle size of the embedded A nanoparticles ranges from 1.0 nm to 20 nm; Furthermore, the particle size of the embedded A nanoparticles ranges from 1.0 nm to 10 nm;

Furthermore, the yield of the two-dimensional titanic acid nanofilm containing embedded A nanoparticles in the product is its weight percent in the final product;

Furthermore, the titanic acid nanofilm containing embedded A nanoparticles has a yield of 50%˜100% in the final product;

Furthermore, the titanic acid nanofilm containing embedded A nanoparticles has a yield of 65%˜100% in the final product;

Furthermore, the titanic acid nanofilm containing embedded A nanoparticles has a yield of 75%˜100% in the final product;

Furthermore, the titanic acid nanofilm containing embedded A nanoparticles has a yield of 85%˜100% in the final product;

Furthermore, the titanic acid nanofilm containing embedded A nanoparticles has a yield of 90%˜100% in the final product;

Furthermore, the titanic acid nanofilm containing embedded A nanoparticles has a yield of 95%˜100% in the final product;

Furthermore, the titanic acid nanofilm containing embedded A nanoparticles has a yield of 99%˜100% in the final product;

It is to be understood that the product of the second aspect thereof is obtained by acid treatment of the product of the first aspect thereof, then the yield of the two-dimensional titanic acid nanofilm containing embedded A nanoparticles described in the second aspect thereof is substantially the same as that of the two-dimensional titanate nanofilm containing embedded A nanoparticles described in the first aspect thereof.

Furthermore, the A nanoparticles comprise at least one of A nanoparticles, A-O nanoparticles;

Furthermore, the composition of the embedded A nanoparticles in the second aspect thereof are consistent with the composition of the embedded A nanoparticles described in the first aspect thereof, as described in detail in the first aspect thereof.

Furthermore,

when the A-group element is mainly composed of elements which are not easily oxidized, comprising Au, Pt, Pd, Ru, Rh, Os, Ir, Ag or a combination thereof, embedded A nanoparticles in a prepared titanic acid nanofilm containing embedded A nanoparticles are also mainly composed of the A-group element, and the A-O content formed by the combination of the A-group element and in the embedded A nanoparticles will be at a lower content. For example, when the A-group element is mainly composed of Au, Pt and Pd, the embedded A nanoparticles are mainly composed of Au—Pt—Pd nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are easily oxidized, comprising Cu, Ni, Fe, Co or a combination thereof, the composition of the embedded A nanoparticles in the prepared titanic acid nanofilm containing embedded A nanoparticles mainly comprises A-O nanoparticles formed by the combination of the A-group element and O. For example, when the A-group element is mainly composed of Cu and Fe, the composition of the embedded A nanoparticles in the titanic acid nanofilm containing embedded A nanoparticles mainly comprises Cu—O nanoparticles and Fe—O nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are easily oxidized is high, the embedded A nanoparticles can contain the elements which are not easily oxidized and the elements which are easily oxidized simultaneously. For example, when the A-group element comprises Au and Cu, and a content of Cu far exceeds that of Au, the embedded A nanoparticles are mainly composed of Au—Cu nanoparticles and Cu—O nanoparticles.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Os, Ir and Cu.

Furthermore, the A-group element comprises at least one of Au and Cu.

Furthermore, the embedded A nanoparticles mainly exist in the two-dimensional titanic acid nanofilm in an embedded manner.

Furthermore, the volume partially embedded in the two-dimensional titanic acid nanofilm, the embedded A nanoparticles also comprise an exposed volume which is not embedded in the nanofilm.

Furthermore, the embedded A nanoparticles are different from ordinary reported nanoparticles which are mainly adsorbed by van der Waals forces (nanoparticles adsorbed by van der Waals forces can move and fall off), which can ensure that the embedded A nanoparticles can be embedded closely with the titanic acid nanofilm (cannot move or fall off). Since the embedded A nanoparticles are distributed in an island shape and cannot be connected due to a spatial hindrance of the titanic acid nanofilm matrix, it is difficult for the embedded A nanoparticles to continue to merge and grow. Therefore, a particle size of the embedded A nanoparticles can remain approximately unchanged during subsequent heating.

In the third aspect, the present invention also relates to a method of preparing a TiO₂nanosheet powder containing embedded A nanoparticles, comprising:

heating the as-prepared product according to the second aspect or the titanic acid nanofilm material prepared by the method according to the second aspect to obtain the TiO₂nanosheet powder containing embedded A nanoparticles.

Furthermore, the time of heat treatment is 1 min˜48 h;

Preferably, the time of heat treatment is 10 min˜3 h;

Furthermore, the temperature range of the heat treatment is 400° C.˜1500° C.; Furthermore, the temperature range of the heat treatment is 400° C.˜1000° C.;

When a low value of the temperature range is selected, a longer time is required to convert the titanic acid nanofilm into TiO₂nano-sheets, and when a high value of the temperature range is selected, a shorter time is required to convert the titanic acid nanofilm into TiO₂nano-sheets;

Furthermore, with the increase of heat treatment temperature and time, the titanic acid nanofilm will shrink in area, increase in thickness, and change from titanic acid nanofilm to TiO₂nano-powder. Since the A nanoparticles embedded in the titanic acid nanofilm are separated and isolated by the titanic acid nanofilm matrix, and the content of embedded A nanoparticles in the matrix is low, together with that the distribution of embedded A nanoparticles is sparse, it is difficult for the as-formed A nanoparticles to continue to merge with each other and grow up, and their sizes and morphologies will be in a stable state in the process of phase transformation and thickening. the particle size of the A nanoparticles will not grow significantly with the increase of the heat treatment temperature and the prolongation of the heat treatment time. If the content of embedded A nanoparticles in the matrix is high, together with that the distribution of embedded A nanoparticles is dense, the embedded A nanoparticles can merge with each other and grow up, and their particle size can grow up significantly with the elevation of the heat treatment temperature and the extension of the heat treatment time;

Furthermore, when the thickness of the generated TiO₂nanosheet does not exceed the outer diameter of the embedded A nanoparticles, the A nanoparticles will be partially embedded and distributed in the TiO₂nanosheet;

Furthermore, when the thickness of the generated TiO₂nanosheet exceeds the outer diameter of the embedded A nanoparticles, the A nanoparticles may be fully or partially embedded and distributed in the TiO₂nanosheet;

Furthermore, the phase composition of the nano-TiO₂in the TiO₂nanosheet powder containing embedded A nanoparticles includes at least one of brookite-type TiO₂, anatase-type TiO₂, and rutile-type TiO₂.

Furthermore, during the heat treatment process, the morphology of the titanic acid nanofilm matrix will further undergo a transformation from a film to a sheet with a significant increase in the thickness, and at the same time, a transformation from titanic acid to TiO₂will also occur.

Specifically, as the heat treatment temperature and the heat treatment time increase, the product of the heat treatment of the titanic acid nanofilms embedded with A nanoparticles undergoes a continuous transformation from “titanic acid nanofilms embedded with A nanoparticles”→“anatase-type TiO₂nanosheets embedded with A nanoparticles”→“rutile-type TiO₂nanosheets embedded with A nanoparticles”.

During the transformation process, the coexistence of two crystalline TiO₂may occur in the products corresponding to certain heat treatment temperatures and times, such as the coexistence of “titanic acid nanofilms embedded with A nanoparticles” and “anatase-type TiO₂nanosheets embedded with A nanoparticles”, as well as the coexistence of “anatase-type TiO₂nanosheets embedded with A nanoparticles” and “rutile TiO₂nanosheets embedded with A nanoparticles”.

Furthermore, the TiO₂nanosheet embedded with A nanoparticles has a shape of sheet;

Furthermore, the TiO₂nanosheet embedded with A nanoparticles has a thickness of 1.0 nm˜40 nm;

Furthermore, the TiO₂nanosheet embedded with A nanoparticles has a thickness of 1.0 nm˜20 nm;

Furthermore, the average area of the TiO₂nanosheets embedded with A nanoparticles is greater than 100 nm²;

Furthermore, the average area of the TiO₂nanosheet embedded with A nanoparticles is greater than 1000 nm²;

Furthermore, the average area of the TiO₂nanosheets embedded with A nanoparticles is greater than 4000 nm²;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜100 nm;

If the content of the embedded A nanoparticles in the matrix is high and the distribution is dense, the A nanoparticles can merge with each other and grow up, and their particle sizes can grow up significantly with the increase of the heat treatment temperature and the prolongation of the heat treatment time;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜50 nm;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜30 nm; Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜20 nm;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜10 nm;

Furthermore, the chemical composition of the TiO₂nanosheets embedded with A nanoparticles includes A-group element, Ti, and O element; wherein the molar ratio of A-group element to Ti satisfies 0<C_A/C_Ti≤0.30;

Furthermore, 0<C_A/C_Ti≤0.20; Furthermore, 0<C_A/C_Ti≤0.10;

Furthermore, the chemical composition of the TiO₂nanosheet powder comprises Ti, O;

Furthermore, the embedded A nanoparticles are present in the TiO₂nanosheet powder mainly by means of embeddedness.

Furthermore, besides the volume of the embedded A nanoparticles partially embedded in the TiO₂nanosheet, the embedded A nanoparticles also comprise an exposed volume which is not embedded in the the TiO₂nanosheet.

Furthermore, wherein the product of the third aspect thereof is obtained by heat treatment of the product of the second aspect thereof, the yield of the TiO₂nanosheets containing embedded A nanoparticles described in the third aspect thereof is in accordance with the yield of the two-dimensional titanic acid nanofilm containing embedded A nanoparticles described in the second aspect thereof, and is also in accordance with the yield of the two-dimensional titanate nanofilm containing embedded A nanoparticles described in the first aspect thereof. See the second aspect thereof and the first aspect thereof in detail.

Furthermore, the A nanoparticles comprise at least one of A nanoparticles, A-O nanoparticles;

Furthermore, the composition of the embedded A nanoparticles in the third aspect thereof is consistent with the composition of the embedded A nanoparticles described in the first aspect and the second aspect, as described in detail the first aspect.

Furthermore,

Furthermore, when the A-group element is mainly composed of elements which are easily oxidized, comprising Cu, Ni, Fe, Co or a combination thereof, the composition of the embedded A nanoparticles in the prepared titanic acid nanofilm containing embedded A nanoparticles mainly comprises A-O nanoparticles formed by the combination of the A-group element and O. For example, when the A-group element is mainly composed of Cu and Fe, the composition of the embedded A nanoparticles in the titanic acid nanofilm containing embedded A nanoparticles mainly comprises Cu—O nanoparticles and Fe—O nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are easily oxidized is high, the embedded A nanoparticles can contain the elements which are not easily oxidized and the elements which are easily oxidized simultaneously. For example, when the A-group element comprises Au and Cu, and a content of Cu far exceeds that of Au, the embedded A nanoparticles are mainly composed of Au—Cu nanoparticles and Cu—O nanoparticles.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Os, Ir and Cu.

Furthermore, the A-group element comprises at least one of Au and Cu.

Furthermore, the embedded A nanoparticles mainly exist in the TiO₂nanosheet powder in an embedded manner.

Furthermore, the volume partially embedded in the the TiO₂nanosheet, the embedded A nanoparticles also comprise an exposed volume which is not embedded in the TiO₂nanosheet.

In the fourth aspect, the present invention also relates to a method of preparing titanate nanotubes containing embedded A nanoparticles, comprising the following steps:

sealing a solid substance with a alkaline solution in a closed vessel, wherein the solid substance is the product or the titanate nanofilm containing embedded A nanoparticles prepared according to the first aspect, or (and) the product or the titanic acid nanofilm containing embedded A nanoparticles prepared according to the second aspect, then the solid substance and the alkaline solution in the closed vessel were treated by a high pressure and a high temperature of T₂which is higher than that of the T_{f solution}; wherein the T_{f solution}is the boiling temperature of the alkali solution involved in the reaction at ambient pressure, and T₁<T_{f solution}<T₂; after a certain time of reaction, the temperature of the closed vessel is reduced and the pressure is restored to ambient pressure, and the final solid product is collected, i.e., the titanate nanotubes containing embedded A nanoparticles are obtained. Wherein, the A nanoparticles comprises at least one of A nanoparticles and A-O nanoparticles.

Furthermore, the alkaline solution includes at least one of NaOH, KOH, LiOH, RbOH, Ba(OH)₂, Ca(OH)₂, Sr(OH)₂solution;

Furthermore, the solvent in the alkaline solution includes water; as a preference, the solvent in the alkaline solution is water;

Furthermore, the concentration of alkali in the alkaline solution is 5.1˜25 mol/L;

As a preference, the concentration of alkali in the alkaline solution is 5.1˜15 mol/L;

As a preference, the concentration of alkali in the alkaline solution is 7˜15 mol/L;

As a furthermore preference, the concentration of alkali in the alkaline solution is 7˜12 mol/L;

As a furthermore preference, the concentration of alkali in the alkaline solution is 10˜15 mol/L;

Furthermore, the concentration of alkaline refers to the concentration of OH⁻ in the alkaline;

Furthermore, the alkali in the alkaline solution mixed with the solid substance containing the titanate nanofilm embedded A nanoparticles as described in the first aspect thereof or (and) the titanic acid nanofilm embedded A nanoparticles as described in the second aspect thereof is in an excess dose of alkali, and the volume of the alkaline solution is more than 5 times the volume of the solid substance;

Furthermore, the volume of the alkaline solution is more than 10 times the volume of the solid substance; Furthermore, the volume of the alkaline solution is more than 20 times the volume of the solid substance;

As a preferred example,

the “solid substance containing a titanate nanofilm containing embedded A nanoparticles as described in the first aspect thereof or (and) a titanic acid nanofilm containing embedded A nanoparticles as described in the second aspect thereof and an alkaline solution” is the solid flocculent product containing containing embedded A nanoparticles and the corresponding alkaline solution after the hydrogen generation and T-removal reaction as described in step (1) and (2) in the first aspect;

i.e.: sealing a solid substance with a alkaline solution in a closed vessel, wherein the solid substance is the solid flocculent product containing embedded A nanoparticles and the corresponding alkaline solution after the hydrogen generation and T-removal reaction as described in step (1) and (2) in the first aspect; then the solid substance and the alkaline solution in the closed vessel were treated by a high pressure and a high temperature of T₂which is higher than that of the T_{f solution}; wherein the T_{f solution}is the boiling temperature of the alkali solution involved in the reaction at ambient pressure, and T₁<T_{f solution}<T₂; after a certain time of reaction, the temperature of the closed vessel is reduced and the pressure is restored to ambient pressure, and the final solid product is collected, i.e., the titanate nanotubes containing embedded A nanoparticles are obtained.

Wherein, the A nanoparticles comprises at least one of A nanoparticles and A-O nanoparticles.

This preferred solution does not require separation of the solid flocculent product containing embedded A nanoparticles and the corresponding alkaline solution, followed by mixing the solid flocculent product containing E-group elements with an alkali, nor does it require the alkaline solution to be cooled down and then warmed up (T₁<T₂), and the alkali concentration meets the requirements of the high temperature and high pressure reaction of this preferred solution. Therefore, this is the most economical and simple operation scheme.

Furthermore, during the high temperature and high pressure treatment, titanate film or (and) titanic acid film is converted to tubular titanate and T₁≤T_{f solution}<T₂;

Furthermore, the reaction is carried out in a closed vessel above atmospheric pressure so that the temperature of the alkaline solution can be heated above its boiling point temperature at atmospheric pressure, T_{f solution}, thereby achieving the conversion of the titanate nonfilm containing embedded A nanoparticles or (and) the titanic acid nanofilm containing embedded A nanoparticles to tubular titanate at high temperature and pressure.

Furthermore, in the closed container, when the alkaline solution species and concentration are determined, a determined value of temperature must correspond to a determined value of pressure, i.e., the value of pressure is a function of the value of temperature; the higher the temperature, the higher the pressure.

Furthermore, T_{f solution}<T₂<300° C.;

Furthermore, T_{f solution}<T₂<250° C.;

Furthermore, T_{f solution}<T₂<200° C.;

Furthermore, T_{f solution}<120° C.<T₂<200° C.;

Furthermore, T_{f solution}<140° C.<T₂<200° C.;

Furthermore, T_{f solution}<150° C.<T₂<180° C.;

Furthermore, the T₂temperature autoclave treatment time is 0.1h˜10 h; Furthermore, the T₂temperature autoclave treatment time is 0.1 h˜1 h; Furthermore, the T₂temperature autoclave treatment time is 0.1 h˜0.5 h; Furthermore preferably, the T₂temperature autoclave treatment time is 0.1 h˜0.2 h;

Since the product can also be obtained by continuing the holding time after the reaction equilibrium, the holding time can also be selected as a longer time value.

Furthermore, the titanate nanotubes containing embedded A nanoparticles have an outer diameter of 2 nm˜25 nm;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have an outer diameter of 3 nm˜15 nm;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have an average length greater than 5 times their average outer diameter.

Furthermore, the particle size of the A nanoparticles ranges from 1.0 nm to 40 nm;

Furthermore, the particle size of the A nanoparticles ranges from 1.0 nm to 20 nm;

Furthermore, the particle size of the A nanoparticles ranges from 1.0 nm to 10 nm;

Furthermore, the titanate nanotubes containing embedded A nanoparticles are mainly low crystallinity titanate;

Furthermore, the embedded A nanoparticles are mainly present in the titanate nanotubes by means of embeddedness;

The embedding refers to a formation mode of in situ generation, i.e., the embedded A nanoparticles are manifested as being partially or completely embedded in the titanate nanotube matrix, which does not rely on external addition or external mixed methods to make it embedded.

Furthermore, the embedded A nanoparticles are embedded in a way that includes part of the A nanoparticles embedded in the titanate nanotubes, and also includes an exposed portion that is not embedded in the titanate nanotubes.

Furthermore, the cationic elements in the titanate nanotubes are derived [289] from the cationic element in the corresponding alkali; Furthermore, the titanate nanotubes embedded with A nanoparticles have a chemical composition including the A-group element, Ti, O, and the cationic element in the corresponding alkali, wherein the molar ratio of the A-group element to Ti satisfies 0<C_A/C_Ti≤0.30; for example, when the alkali is NaOH, the corresponding cationic element in the alkali is Na, and the chemical composition of the titanate nanotubes containing embedded A nanoparticles comprises the A-group element, Ti, O, and Na; Furthermore, 0<C_A/C_Ti≤0.20; Furthermore, 0<C_A/C_Ti≤0.10;

Furthermore, the A nanoparticles are nanoparticles mainly composed of the A-group element.

Furthermore, the A-O nanoparticles are oxide nanoparticles mainly formed by a combination of the A-group element and O.

Furthermore, the A-O nanoparticles formed by the combination of the A-group element with different valences and O.

Furthermore,

when the A-group element is mainly composed of elements which are not easily oxidized, comprising Au, Pt, Pd, Ru, Rh, Os, Ir, Ag or a combination thereof, the embedded A nanoparticles in a prepared titanate nanotubes containing embedded A nanoparticles are also mainly composed of the A-group element, and the A-O content formed by the combination of the A-group element and O in the embedded A nanoparticles will be at a lower content. For example, when the A-group element is mainly composed of Au, Pt and Pd, the embedded A nanoparticles are mainly composed of Au—Pt—Pd nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are easily oxidized, comprising Cu, Ni, Fe, Co or a combination thereof, the composition of the embedded A nanoparticles in the prepared titanate nanotubes containing embedded A nanoparticles mainly comprises A-O nanoparticles formed by the combination of the A-group element and O. For example, when the A-group element is mainly composed of Cu and Fe, the composition of the embedded A nanoparticles in the titanate nanotubes containing embedded A nanoparticles mainly comprises Cu—O nanoparticles and Fe—O nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are easily oxidized is high, the embedded A nanoparticles can contain the elements which are not easily oxidized and the elements which are easily oxidized simultaneously. For example, when the A-group element comprises Au and Cu, and a content of Cu far exceeds that of Au, the embedded A nanoparticles are mainly composed of Au—Cu nanoparticles and Cu—O nanoparticles.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Os, Ir and Cu.

Furthermore, the A-group element comprises at least one of Au and Cu.

Furthermore, the yield of the titanate nanotubes containing embedded A nanoparticles in the final solid product is its weight percent in the final product;

Furthermore, the titanate nanotubes containing embedded A nanoparticles are mainly prepared by high temperature and high-pressure treatment of titanate nanofilms containing embedded A nanoparticles, so that when the high temperature and high pressure treatment is incomplete, the as-prepared product will also contain titanate nanofilms containing embedded A nanoparticles.

Furthermore, the titanate nanotubes containing embedded A nanoparticles have a weight percentage content of more than 50% in the final product;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have a weight percentage content higher than 90% in the final product;

In the fifth aspect, the present invention also relates to a method of preparing a titanic acid nanotube material containing embedded A nanoparticles is provided, comprising:

reacting the product prepared according to the fourth aspect or the titanate nanotube material containing embedded A nanoparticles prepared according to the fourth aspect with an acid solution, and collecting the solid product, i.e., obtaining the titanic acid nanotube material containing embedded A nanoparticles.

Furthermore, the acid solution includes at least one of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid, oxalic acid, picric acid, oleic acid, perchloric acid.

By reacting with the acid solution, the residual alkali adsorbed on the surface of the titanate nanotube material containing embedded A nanoparticles is firstly neutralized, and then ion exchange occurs between the cations in the titanate nanotube material and hydrogen ions in the acid solution, thereby obtaining the titanic acid nanotube material containing embedded A nanoparticles.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.09 mol/L.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.05 mol/L.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.01 mol/L.

Furthermore, the step of reacting the titanate nanotube material containing embedded A nanoparticles with the acid solution comprises: 1) when the embedded A nanoparticles contain A-O nanoparticles, dispersing the titanate nanotube material containing embedded A nanoparticles in water, gradually adding the acid solution in the mixed solution with constant stirring, so as to make pH of the mixed solution continuously reduce and ultimately maintain between 3-5, i.e., the corresponding concentration of the hydrogen ions in the mixed solution is 0.00001.0˜0.001 mol/L. After 1 min to 5 h, subjecting the mixed solution to separation, washing and drying, so as to obtain the titanic acid nanotube material containing embedded A nanoparticles. 2) When the embedded A nanoparticles do not contain A-O nanoparticles, the titanate nanotube material containing embedded A nanoparticles is dispersed in water, and under stirring, the acid solution is gradually added thereto to make the pH value of the mixed solution decrease continuously and ultimately the PH value of the mixed solution is controlled to be maintained between 2 and 5, i.e., the corresponding concentration of the hydrogen ions in the mixed solution is 0.00001.0˜0.01 mol/L. After 1 min to 5 h, separation, cleaning, and drying are carried out to obtain the titanic acid nanotube containing embedded A nanoparticles.

Furthermore, the A nanoparticles have a particle size range of 1.0 nm˜40 nm;

Furthermore, the A nanoparticles have a particle size range of 1.0 nm˜20 nm;

Furthermore, the A nanoparticles have a particle size range of 1.0 nm˜10 nm;

Furthermore, the titanic acid nanotubes containing embedded A nanoparticles have an outer diameter range of 2 nm˜25 nm;

Furthermore, the titanic acid nanotubes containing embedded A nanoparticles have an outer diameter range of 3 nm˜15 nm;

Furthermore, the titanic acid nanotubes containing embedded A nanoparticles have an average length greater than 5 times their average outer diameter;

Furthermore, the titanic acid nanotubes containing embedded A nanoparticles are predominantly low crystallinity titanic acid;

Furthermore, the embedded A nanoparticles are predominantly present in titanic acid nanotubes by means of embeddedness;

Furthermore, the embedded A nanoparticles comprise, in addition to a portion of volume embedded in the titanic acid nanotubes, a portion of volume that is not embedded in the titanic acid nanotubes;

Furthermore, the titanic acid nanotubes containing embedded A nanoparticles have a chemical composition comprising A-group element, Ti, O, H; wherein the molar ratio of the A-group element to Ti satisfies 0<C_A/C_Ti≤0.30; Furthermore, 0<C_A/C_Ti≤0.20; and Furthermore, 0<C_A/C_Ti≤0.10;

Furthermore, the chemical composition of the titanic acid nanotube matrix comprises Ti, O, H;

Furthermore, the A nanoparticles comprise at least one of A nanoparticles, A-O nanoparticles;

Furthermore, the A nanoparticles are nanoparticles mainly composed of A-group element;

Furthermore, the A-O nanoparticles are oxide nanoparticles mainly formed by combining A-group element with O;

Furthermore, the A-O nanoparticles formed by the combination of the A-group element with different valences and O.

Furthermore, the product of the fifth aspect thereof is obtained by reacting the product of the fourth aspect thereof with an acid solution, and thus the composition of the embedded A nanoparticles of the fifth aspect thereof is consistent with the composition of the embedded A nanoparticles described in the fourth aspect thereof, as described in detail in the fourth aspect thereof.

Furthermore,

when the A-group element is mainly composed of elements which are not easily oxidized, comprising Au, Pt, Pd, Ru, Rh, Os, Ir, Ag or a combination thereof, the embedded A nanoparticles in a prepared titanic acid nanotubes containing embedded A nanoparticles are also mainly composed of the A-group element, and the A-O content formed by the combination of the A-group element and O in the embedded A nanoparticles will be at a lower content. For example, when the A-group element is mainly composed of Au, Pt and Pd, the embedded A nanoparticles are mainly composed of Au—Pt—Pd nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are easily oxidized, comprising Cu, Ni, Fe, Co or a combination thereof, the composition of the embedded A nanoparticles in the prepared titanic acid nanotubes containing embedded A nanoparticles mainly comprises A-O nanoparticles formed by the combination of the A-group element and O. For example, when the A-group element is mainly composed of Cu and Fe, the composition of the embedded A nanoparticles in the titanic acid nanotubes containing embedded A nanoparticles mainly comprises Cu—O nanoparticles and Fe—O nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are easily oxidized is high, the embedded A nanoparticles can contain the elements which are not easily oxidized and the elements which are easily oxidized simultaneously. For example, when the A-group element comprises Au and Cu, and a content of Cu far exceeds that of Au, the embedded A nanoparticles are mainly composed of Au—Cu nanoparticles and Cu—O nanoparticles.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Os, Ir and Cu.

Furthermore, the A-group element comprises at least one of Au and Cu.

In the sixth aspect, the present invention also relates to a method of preparing a TiO₂nanotubes/rods containing embedded A nanoparticles, comprising:

heating the as-prepared product according to the fifth aspect or the titanic acid nanotube containing embedded A nanoparticles prepared by the method according to the fifth aspect to obtain the TiO₂nanotubes/rods containing embedded A nanoparticles.

Furthermore, the temperature range of the heat treatment is 400° C.˜1500° C.;

Furthermore, the temperature range of the heat treatment is 400° C.˜1000° C.;

Furthermore, the time of heat treatment is 1 min˜48 h;

Preferably, the time of heat treatment is 10 min˜3 h;

When a low value of the temperature range is selected, a longer time is required to convert the titanic acid nanotube into TiO₂nanotubes/rods, and when a high value of the temperature range is selected, a shorter time is required to convert the titanic acid nanotube into TiO₂nanotubes/rods;

Furthermore, with the increase of heat treatment temperature and time, the titanic acid nanotube transforms into the TiO₂nanotubes/rods. Since the A nanoparticles embedded in the titanic acid nanotube are separated and isolated by the titanic acid nanotube matrix, and the content of embedded A nanoparticles in the matrix is low, together with that the distribution of embedded A nanoparticles is sparse, it is difficult for the as-formed A nanoparticles to continue to merge with each other and grow up, and their sizes and morphologies will be in a stable state in the process of phase transformation. The particle size of the A nanoparticles will not grow significantly with the increase of the heat treatment temperature and the prolongation of the heat treatment time. If the content of embedded A nanoparticles in the matrix is high, together with that the distribution of embedded A nanoparticles is dense, the embedded A nanoparticles can merge with each other and grow up, and their particle size can grow up significantly with the elevation of the heat treatment temperature and the extension of the heat treatment time;

Furthermore, the crystalline TiO₂nanotubes/rods means that the shape of the crystalline TiO₂nanotubes/rods comprises at least one of tube and rod; when the inner diameter of the tube is reduced to zero, it is the shape of a rod;

Furthermore, the phase composition of the TiO₂nanotubes/rods containing the A nanoparticles includes at least one of brookite-type nano-TiO₂, anatase-type nano-TiO₂, and rutile-type nano-TiO₂.

Specifically, as the heat treatment temperature and the heat treatment time increase, the product of the heat treatment of the TiO₂nanotubes containing the A nanoparticles undergoes a continuous transformation from “titanic acid nanotube embedded with A nanoparticles”→“anatase-type TiO₂nanotube embedded with A nanoparticles”→“rutile-type TiO₂nanotube/rod embedded with A nanoparticles”.

During the transformation process, the coexistence of two crystalline TiO₂may occur in the products corresponding to certain heat treatment temperatures and times, such as the coexistence of “titanic acid nanotube embedded with A nanoparticles” and “anatase-type TiO₂nanotube embedded with A nanoparticles”, as well as the coexistence of “anatase-type TiO₂nanotube embedded with A nanoparticles” and “rutile TiO₂nanotube embedded with A nanoparticles”.

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜100 nm;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜60 nm;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜30 nm;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜20 nm;

Furthermore, the embedded A nanoparticles have a size of 1.0 nm˜10 nm;

Furthermore, the TiO₂nanotubes/rods containing embedded A nanoparticles have an average length greater than 3 times their average outer diameter;

Furthermore, the TiO₂nanotubes/rods containing embedded A nanoparticles have an outer diameter of 2 nm˜25 nm;

Furthermore, the TiO₂nanotubes/rods containing embedded A nanoparticles have an outer diameter of 3 nm˜20 nm;

Furthermore, the embedded A nanoparticles are present in crystalline TiO₂nanotubes/rods mainly by means of embeddedness;

Furthermore, besides the volume of the embedded A nanoparticles partially embedded in the TiO₂nanotubes/rods, the embedded A nanoparticles also comprise an exposed volume which is not embedded in the the TiO₂nanotubes/rods.

Furthermore, the chemical composition of the crystalline TiO₂nanotubes/rods embedded with A nanoparticles includes A-group element, Ti, and O element; wherein the molar ratio of A-group element to Ti satisfies 0<C_A/C_Ti≤0.30;

Furthermore, 0<C_A/C_Ti≤0.20; Furthermore, 0<C_A/C_Ti≤0.10;

Furthermore, the chemical composition of the TiO₂nanotube/rod matrix comprises Ti, O;

Furthermore, the A nanoparticles comprise at least one of A nanoparticles, A-O nanoparticles;

Furthermore, the A nanoparticles are nanoparticles mainly composed of A-group element;

Furthermore, the A-O nanoparticles are oxide nanoparticles mainly formed by combining A-group element with O;

Furthermore, the A-O nanoparticles formed by the combination of the A-group element with different valences and O.

Furthermore, the product of the sixth aspect thereof is a subsequent product of the product described in the fourth aspect or in the fifth aspect, so that the composition of the embedded A nanoparticles described in the sixth aspect is consistent with the composition of the embedded A nanoparticles described in the fourth aspect, and also with the composition of the embedded A nanoparticles described in the fifth aspect, as described in detail in the fourth aspect thereof.

Furthermore,

when the A-group element is mainly composed of elements which are not easily oxidized, comprising Au, Pt, Pd, Ru, Rh, Os, Ir, Ag or a combination thereof, embedded A nanoparticles in a prepared crystalline TiO₂nanotubes/rods containing embedded A nanoparticles are also mainly composed of the A-group element, and the A-O content formed by the combination of the A-group element and O in the embedded A nanoparticles will be at a lower content. For example, when the A-group element is mainly composed of Au, Pt and Pd, the embedded A nanoparticles are mainly composed of Au—Pt—Pd nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are easily oxidized, comprising Cu, Ni, Fe, Co or a combination thereof, the composition of the embedded A nanoparticles in the prepared crystalline TiO₂nanotubes/rods containing embedded A nanoparticles mainly comprises A-O nanoparticles formed by the combination of the A-group element and O. For example, when the A-group element is mainly composed of Cu and Fe, the composition of the embedded A nanoparticles in the crystalline TiO₂nanotubes/rods containing embedded A nanoparticles mainly comprises Cu—O nanoparticles and Fe—O nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are easily oxidized is high, the embedded A nanoparticles can contain the elements which are not easily oxidized and the elements which are easily oxidized simultaneously. For example, when the A-group element comprises Au and Cu, and a content of Cu far exceeds that of Au, the embedded A nanoparticles are mainly composed of Au—Cu nanoparticles and Cu—O nanoparticles.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Os, Ir and Cu.

Furthermore, the A-group element comprises at least one of Au and Cu.

In the seventh aspects, the present invention also relates to another method of preparing titanate nanotubes containing embedded A nanoparticles, which are prepared by the following steps:

- step 1), providing an initial alloy comprising T-type elements, Ti and A-group element; and the phase composition of the initial alloy comprises a T-Ti intermetallic compound with solid dissolved A-group elements; wherein the T-type elements comprise at least one of Al and Zn; the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Re, Os, Ir, Ag, Cu, Ni, Fe and Co, and when the A-group element contains Ag, the atomic percentage content of Ag in A is less than 50%;
- step 2), sealing the initial alloy with the alkaline solution in a closed vessel, and subsequently heating the closed reaction system to the temperature of T₂and holding it for a certain period of time; wherein 100° C.<T_{f solution}<T₂; T_{f solution}is the boiling point temperature of the alkaline solution involved in the reaction at ambient pressure, and the pressure in the reaction vessel at the temperature of T₂is higher than the ambient pressure;
- step 3), lowering the temperature of the closed vessel and restoring the pressure to ambient pressure, and collecting the final solid product, i.e., obtaining the titanate nanotubes containing embedded A nanoparticles; wherein the A nanoparticles comprise at least one of A nanoparticles and A-O nanoparticles.

The step 1), as well as the detailed description of step 1), are identical to the step (1) and its detailed description described in the first aspect (a method of preparing a titanate nanofilm material containing embedded A nanoparticles), (as can be seen in the step (1) described in the first aspect).

In the step 2),

Furthermore, the initial alloy and the alkaline solution are sealed in a closed vessel at room temperature and pressure, and the temperature of the closed reaction system is subsequently heated to a high temperature of T₂and held for a certain period of time; wherein 100° C.<T_{f solution}<T₂;

Furthermore, the alkaline solution includes at least one of NaOH, KOH, LiOH, RbOH, Ba(OH)₂, Ca(OH)₂, Sr(OH)₂solution;

Furthermore, the solvent in the alkaline solution includes water; as a preference, the solvent in the alkaline solution is water;

Furthermore, the concentration of alkali in the alkaline solution is 5.1˜25 mol/L;

As a preference, the concentration of alkali in the alkaline solution is 5.1˜15 mol/L;

As a preference, the concentration of alkali in the alkaline solution is 7˜15 mol/L; as a Furthermore preference, the concentration of alkali in the alkaline solution is 7˜12 mol/L;

As a Furthermore preference, the concentration of alkali in the alkaline solution is 10˜15 mol/L;

Furthermore, the concentration of alkaline refers to the concentration of OH⁻ in the alkaline;

Furthermore, the volume of the alkaline solution is more than 10 times the volume of the initial alloy;

Furthermore, the volume of the alkaline solution is more than 20 times the volume of the initial alloy;

Furthermore, the temperature at which the initial alloy reacts with the alkaline solution is the temperature of the alkaline solution;

It can be understood that the reaction between the initial alloy and the alkaline solution is very slow in the preparation and beginning stages of the reaction at room temperature and atmospheric pressure, and that after the initial alloy and the alkaline solution are sealed in a closed container, the hydrogen generated by the reaction between the T-type elements in the initial alloy and the alkaline solution is also sealed in the closed container, which causes the pressure of the closed container to be elevated.

Furthermore, the closed reaction system includes, an initial alloy, an alkaline solution, and a closed container; the temperature of the closed reaction system is the temperature corresponding to the initial alloy, the alkaline solution, and the closed container;

Furthermore, the temperature of the initial alloy and the alkaline solution in the closed container is heated to the T₂temperature at a heating rate of greater than 10° C./min from room temperature;

Furthermore, the time for heating the temperature of the initial alloy and the alkaline solution in the closed container from room temperature to the T₂temperature is less than 30 min;

Furthermore, 100° C.<T_{f solution}<T₂<300° C.;

Furthermore, 100° C.<T_{f solution}<T₂<250° C.;

Furthermore, 100° C.<T_{f solution}<T₂<200° C.;

Furthermore, 100° C.<T_{f solution}<120° C.<T₂<200° C.;

Furthermore, 100° C.<T_{f solution}<140° C.<T₂<200° C.;

Furthermore, 100° C.<T_{f solution}<150° C.<T₂<180° C.;

Furthermore, the holding time of the closed reaction system at the T₂temperature is 0.1 h h; preferably 0.1 h˜2 h, preferably 0.1 h˜1 h, preferably 0.1 h˜0.5 h, further preferably 0.2 h˜0.4 h;

Since the product can also be obtained by continuing the holding time after the reaction has equilibrated, the holding time can also be selected as a longer time value.

Furthermore, the initial alloy in the closed vessel and the alkaline solution undergoes a hydrogen generation and T-removal reaction in the heating stage from room temperature to T₂temperature, which mainly generates nanoporous titanate intermediate products containing embedded A nanoparticles.

Furthermore, the conversion of the nanoporous titanate intermediate products containing embedded A nanoparticles to titanate nanotubes containing embedded A nanoparticles occurs during the holding stage at T₂temperature of the closed reaction system;

Furthermore, the pressure of the closed reaction system is higher than the atmospheric pressure;

Furthermore, the pressure of the closed reaction system is a combination of the pressure of the solution of the closed system at the temperature of T₂and the pressure of the hydrogen produced by the hydrogen evolution reaction at the temperature of T₂;

It can be understood that, because of the presence of the pressure of the generated hydrogen gas, the pressure of the closed reaction system is higher than the pressure corresponding to the simple closed system solution at the temperature of T₂; such a high-pressure environment creates conditions for the transformation of the nanoporous titanate intermediate product containing embedded A nanoparticles to the titanate nanotubes containing embedded A nanoparticles;

In the step 3).

Furthermore, the particle size of the A nanoparticles ranges of 1.0 nm˜35 nm;

Furthermore, the particle size of the A nanoparticles ranges of 1.0 nm˜25 nm;

Furthermore, the particle size of the A nanoparticles ranges of 1.0 nm˜15 nm;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have an outer diameter ranging of 2 nm˜25 nm;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have an outer diameter ranging of 3 nm˜20 nm;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have an average length greater than 5 times their average outer diameter.

Furthermore, the titanate nanotubes containing embedded A nanoparticles are predominantly low crystallinity titanate;

Furthermore, the embedded A nanoparticles are predominantly present in the titanate nanotubes by means of embeddedness;

Furthermore, the cationic elements in the titanate nanotubes are derived [289] from the cationic element in the corresponding alkali;

Furthermore, the titanate nanotubes embedded with A nanoparticles have a chemical composition including the A-group element, Ti, O, and the cationic element in the corresponding alkali, wherein the molar ratio of the A-group element to Ti satisfies 0<C_A/C_Ti≤0.30; for example, when the alkali is NaOH, the corresponding cationic element in the alkali is Na, and the chemical composition of the titanate nanotubes containing embedded A nanoparticles comprises the A-group element, Ti, O, and Na;

Furthermore, 0<C_A/C_Ti≤0.20; Furthermore, 0<C_A/C_Ti≤0.10;

Furthermore, the titanate nanotubes matrix has a chemical composition including the Ti, O, and the cationic element in the corresponding alkali;

Furthermore, the A nanoparticles are nanoparticles mainly composed of the A-group element.

Furthermore, the A-O nanoparticles are oxide nanoparticles mainly formed by a combination of the A-group element and O.

Furthermore, the A-O nanoparticles formed by the combination of the A-group element with different valences and O.

Furthermore,

Furthermore, when the A-group element is mainly composed of elements which are easily oxidized, comprising Cu, Ni, Fe, Co or a combination thereof, the composition of the embedded A nanoparticles in the prepared titanate nanotubes containing embedded A nanoparticles mainly comprises A-O nanoparticles formed by the combination of the A-group element and O. For example, when the A-group element is mainly composed of Cu and Fe, the composition of the embedded A nanoparticles in the titanate nanotubes containing embedded A nanoparticles mainly comprises Cu—O nanoparticles and Fe—O nanoparticles.

Furthermore, when the A-group element is mainly composed of elements which are not easily oxidized and elements which are easily oxidized, and the content of the elements which are easily oxidized is high, the embedded A nanoparticles can contain the elements which are not easily oxidized and the elements which are easily oxidized simultaneously. For example, when the A-group element comprises Au and Cu, and a content of Cu far exceeds that of Au, the embedded A nanoparticles are mainly composed of Au—Cu nanoparticles and Cu—O nanoparticles.

Furthermore, the A-group element comprises at least one of Au, Pt, Pd, Ru, Rh, Os, Ir and Cu.

Furthermore, the A-group element comprises at least one of Au and Cu.

Furthermore, the yield of the titanate nanotubes containing embedded A nanoparticles in the final solid product is its weight percent in the final product;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have a yield of 90%˜100% in the final product;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have a yield of 95%˜100% in the final product;

Furthermore, the titanate nanotubes containing embedded A nanoparticles have a yield of 99%˜100% in the final product.

In the eighth aspect, the present invention also relates to a method of preparing a titanic acid nanotube material containing embedded A nanoparticles is provided, comprising:

reacting the product prepared according to the seventh aspect or the titanate nanotube material containing embedded A nanoparticles prepared according to the seventh aspect with an acid solution, and collecting the solid product, i.e., obtaining the titanic acid nanotube material containing embedded A nanoparticles.

Furthermore, the acid solution includes at least one of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid, oxalic acid, picric acid, oleic acid, perchloric acid.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.09 mol/L.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.05 mol/L.

Furthermore, the concentration of the hydrogen ions in the acid solution is 0.0001.0˜0.01 mol/L.

Furthermore, the A nanoparticles have a particle size range of 1.0 nm˜35 nm;

Furthermore, the A nanoparticles have a particle size range of 1.0 nm˜25 nm;

Furthermore, the A nanoparticles have a particle size range of 1.0 nm˜15 nm;