Patent Application
20250075342
The present invention relates to an electrolysis apparatus and an electrolysis method for producing a useful compound from carbon dioxide (CO2).
Carbon dioxide (CO2) emissions have been rapidly increasing by an annual average of 3.1% since 2000, and climate change resulting from the CO2 emissions is recognized as a major global problem. As a solution to the above problem, efforts have been made to reduce the CO2 emissions in the field of energy (thermal power generation), the field of industry (steel mills, chemical plants, cement plants, etc.), and the field of transportation (cars, ships, etc.) through introduction of eco-friendly power generation technologies and improvement of energy utilization efficiency. In addition, research and development on technologies for capturing and storing generated CO2 (carbon capture & sequestration (CCS)) have been conducted, and in particular, technologies for recycling CO2 as resources are actively studied recently in major advanced countries such as United States and Japan.
One technical object of the present invention is to provide an apparatus and a method for electrolyzing carbon dioxide.
Another technical object of the present invention is to provide an electrolysis apparatus and an electrolysis method for producing a useful compound from carbon dioxide.
Still another technical object of the present invention is to provide an electrolysis apparatus and an electrolysis method for producing ethanol from carbon dioxide.
Yet another technical object of the present invention is to provide an electrolysis apparatus and an electrolysis method for producing acetone from carbon dioxide.
Still yet another technical object of the present invention is to provide an apparatus and a method capable of improving electrolysis efficiency of carbon dioxide.
Technical objects of the present invention are not limited to the technical objects described above.
To achieve the technical objects described above, the present invention provides an electrolysis apparatus.
According to one embodiment, the electrolysis apparatus includes: an anode module configured to electrochemically oxidize water (H2O) to generate an oxide including oxygen (O2) and hydrogen ions (protons); a cathode module arranged opposite to the anode module, and configured to electrochemically reduce carbon dioxide (CO2) to generate a reduced material including ethanol and acetone; and a separation module configured to receive the reduced material from the cathode module, and separate the ethanol or the acetone from the reduced material.
According to one embodiment, the cathode module may include: a cathode compartment configured to accommodate the carbon dioxide; and a cathode disposed on one side of the cathode compartment, and configured to receive the carbon dioxide from the cathode compartment, the hydrogen ions generated from the anode module may be moved from the anode module to the cathode, and the cathode may be configured to electrochemically reduce the carbon dioxide by using the hydrogen ions moved from the anode module to generate the reduced material.
According to one embodiment, the cathode may include a catalyst in which nitrogen-doped porous carbon is coated with a single atom metal, which includes one kind of a single atom metal or a single atom dimer (SAD) in which two kinds of single atom metals are combined.
According to one embodiment, the cathode module may include a gas diffusion layer (GDL) disposed between the cathode compartment and the cathode to diffuse the carbon dioxide from the cathode compartment to the cathode.
According to one embodiment, the anode module may include: an anode compartment configured to accommodate an anode electrolyte; and an anode disposed on one side of the anode compartment.
According to one embodiment, in the electrolysis apparatus, a cation exchange membrane may be disposed between the anode module and the cathode module.
According to one embodiment, the separation module may be configured to separate the ethanol or the acetone from the reduced material by using a difference in solubility for salt.
According to one embodiment, the separation module may be configured to separate the ethanol or the acetone from the reduced material by using a difference in boiling points.
According to one embodiment, the electrolysis apparatus may further include a monitoring system configured to identify a composition of the reduced material generated from the cathode module.
To achieve the technical objects described above, the present invention provides an electrolysis method.
According to one embodiment, the electrolysis method includes: supplying an anode electrolyte and water (H2O) to an anode; supplying carbon dioxide (CO2) to a cathode; generating a potential difference between the anode and the cathode to electrochemically oxidize the water through the anode and electrochemically reduce the carbon dioxide through the cathode; and separating ethanol or acetone from a reduced material of the carbon dioxide electrochemically reduced through the cathode.
According to one embodiment, an oxide of the water electrochemically oxidized through the anode may include oxygen (O2) and hydrogen ions (protons), the reduced material of the carbon dioxide electrochemically reduced through the cathode may include ethanol and acetone, and the hydrogen ions may be moved to the cathode and used to electrochemically reduce the carbon dioxide.
According to one embodiment, in the electrolysis method, the ethanol or the acetone may be separated from the reduced material of the carbon dioxide by using a difference in solubility for salt, or the ethanol or the acetone may be separated from the reduced material of the carbon dioxide by using a difference in boiling points.
To achieve the technical objects described above, the present invention provides a membrane electrode assembly (MEA).
According to one embodiment, the membrane electrode assembly includes: an anode; a cathode; and an ion conductive polymer membrane disposed between the anode and the cathode, wherein the ion conductive polymer membrane includes a first ion conductive polymer membrane adjacent to the anode, and a second ion conductive polymer membrane adjacent to the cathode, and a discontinuous polymer interface is formed between the first ion conductive polymer membrane and the second ion conductive polymer membrane.
According to one embodiment, the cathode includes a catalyst in which nitrogen-doped porous carbon is coated with a single atom metal, which includes one kind of a single atom metal or a single atom dimer (SAD) in which two kinds of single atom metals are combined.
According to an embodiment of the present invention, an electrolysis apparatus includes: an anode module configured to electrochemically oxidize water (H2O) to generate an oxide including oxygen (O2) and hydrogen ions (protons); a cathode module arranged opposite to the anode module, and configured to electrochemically reduce carbon dioxide (CO2) to generate a reduced material including ethanol and acetone; and a separation module configured to receive the reduced material from the cathode module, and separate the ethanol or the acetone from the reduced material. Accordingly, useful compounds such as ethanol and acetone can be easily generated from carbon dioxide.
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical idea of the present invention is not limited to the embodiments described herein, but may be embodied in different forms. The embodiments introduced herein are provided to sufficiently deliver the idea of the present invention to those skilled in the art so that the disclosed contents may become thorough and complete.
When it is mentioned in the present disclosure that one element is on another element, it means that one element may be directly formed on another element, or a third element may be interposed between one element and another element. Further, in the drawings, thicknesses of films and regions are exaggerated for effective description of the technical contents.
In addition, although the terms such as first, second, and third have been used to describe various elements in various embodiments of the present disclosure, the elements are not limited by the terms. Therefore, an element mentioned as a first element in one embodiment may be mentioned as a second element in another embodiment.
The embodiments described and illustrated herein include their complementary embodiments, respectively. Further, the term “and/or” used in the present disclosure is used to include at least one of the elements enumerated before and after the term.
As used herein, an expression in a singular form includes a meaning of a plural form unless the context clearly indicates otherwise. Further, the terms such as “including” and “having” are intended to designate the presence of features, numbers, steps, elements, or combinations thereof described herein, and shall not be construed to preclude any possibility of the presence or addition of one or more other features, numbers, steps, elements, or combinations thereof.
Further, in the following description of the present invention, detailed descriptions of known functions or configurations incorporated herein will be omitted when they may make the gist of the present invention unnecessarily unclear.
Referring to
The power source 100 may be a device for generating a potential difference between an anode and a cathode, and may apply a DC voltage to an anode 220 and a cathode 320, which will be described below.
The anode module 200 may include an anode compartment 210 and an anode 220. The anode compartment 210 and the anode 220 may be adjacent to each other.
An anode electrolyte AE may be supplied to the anode compartment 210 through the anode electrolyte supply module 600. In addition, water (H2O) may be supplied to the anode compartment 210. The water (H2O) may be supplied together with the anode electrolyte AE through the anode electrolyte supply module 600, or may be supplied through a separate supply module (not shown). A method for supplying the water (H2O) into the anode compartment 210 is not limited.
According to one embodiment, the anode electrolyte AE may include one of H2SO4, HNO3, HCl, and H3PO4. A type of the anode electrolyte AE is not limited. According to one embodiment, a first pump P1 may be disposed in a flow path that connects the anode compartment 210 and the anode electrolyte supply module 600, and a flow rate of the anode electrolyte AE supplied to the anode compartment 210 may be controlled through the first pump P1. In addition, as shown in
The anode 220 may electrochemically oxidize the water (H2O). According to one embodiment, the anode 220 may include a catalyst that is active in the electrolysis of the water. For example, the catalyst included in the anode 220 may include Pt, Au, Pd, Ir, Ag, Rh, Ru, Ni, Al, Mo, Cr, Cu, Ti, W, an alloy thereof, or a mixed metal oxide. In more detail, a titanium (Ti) mesh coated with platinum (Pt) may be used as the anode 220.
An oxide of the water (H2O) electrochemically oxidized through the anode 220 may include oxygen (O2) and hydrogen ions (protons). The hydrogen ions generated from the anode 220 may be moved to the cathode module 300 that will be described below. Alternatively, the oxygen (O2) generated from the anode 220 may be discharged to an outside of the anode module 200.
The cathode module 300 may include a cathode compartment 310, a cathode 320, and a gas diffusion layer (GDL) 330. The cathode compartment 310 and the cathode 320 may be arranged opposite to each other while being spaced apart from each other, and the gas diffusion layer 330 may be disposed between the cathode compartment 310 and the cathode 320. In addition, the cathode module 300 may be arranged opposite to the anode module 200 while being spaced apart from the anode module 200, the cation exchange membrane 400 that will be described below may be disposed between the anode module 200 and the cathode module 300, and the anode 220 and the cathode 320 may be adjacent to the cation exchange membrane 400.
Gaseous carbon dioxide (CO2) including humidified water HW may be supplied to the cathode compartment 310 through the carbon dioxide supply module 710 and the humidified water supply module 720. In other words, the carbon dioxide may be supplied to the cathode compartment 310 in a humidified state. As described above, when the gaseous carbon dioxide (CO2) including the humidified water HW is supplied, a large amount of carbon dioxide may be supplied as compared with a case in which carbon dioxide is supplied alone, so that electrolysis efficiency of the cathode 320 may be improved. According to one embodiment, the gaseous carbon dioxide (CO2) may be supplied from the carbon dioxide supply module 710 to the humidified water supply module 720, and the humidified water supply module 720 may perform bubbling on the gaseous carbon dioxide (CO2) and the humidified water HW and supply the gaseous carbon dioxide (CO2) and the humidified water HW to the cathode compartment 310. According to one embodiment, a second pump P2 may be disposed in a flow path that connects the humidified water supply module 720 and the cathode compartment 310, and a flow rate of a reactant (HW+CO2) supplied to the cathode compartment 310 may be controlled through the second pump P2.
The cathode 320 may electrochemically reduce the carbon dioxide (CO2). In more detail, the reactant (HW+CO2) supplied to the cathode compartment 310 may react with electrons (e−) and the hydrogen ions moved from the anode module 200 at the cathode 320 to generate a reduced material.
The cathode 320 may include a catalyst that is active in electrolysis of the carbon dioxide and capable of generating ethanol and acetone from the carbon dioxide. According to one embodiment, the cathode 320 may be defined as a layer (or a membrane) formed by coating the cation exchange membrane 400 that will be described below with the catalyst.
According to one embodiment, the catalyst included in the cathode 320 may be configured such that nitrogen-doped porous carbon (e.g., a carbon matrix) is coated with a single atom metal. The single atom metal may include a single atom dimer (SAD) in which two kinds of single atom metals are combined as shown in (a) of
Each of the first single atom metal M1 and the second single atom metal M2 may include one of Ni, Co, Sc, Ti, V, Cr, Mn, Fe, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ag, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
According to one embodiment, the first single atom metal M1 and the second single atom metal M2 may be different from each other. Alternatively, according to another embodiment, the first single atom metal M1 and the second single atom metal M2 may be identical to each other.
For example, as the single atom dimer (SAD), Fe—Ni, Fe—Co, Fe—Mn, Cu—Ni, Fe—Cu, Mn—Cu, Cu—Ni, Mn—Ni, Mn—Co, Ni—Co, Mn—Mn, Ni—Ni, Co—Cu, Co—Ag, Fe—Ag, Cu—Ag, Mn—Ag, Ni—Ag, Pd—Fe, Pd—Mn, Pd—Ni, Pd—Co, Pd—Cu, Pd—Ag, Au—Fe, Au—Mn, Au—Ni, Au—Co, Au—Cu, Au—Ag, Au—Pd, Pt—Fe, Pt—Mn, Pt—Ni, Pt—Co, Pt—Cu, Pt—Ag, Pt—Pd, Pt—Au, Ru—Fe, Ru—Mn, Ru—Ni, Ru—Co, Ru—Cu, Ru—Ag, Ru—Pd, Ru—Au, Ru—Pt, Ir—Fe, Ir—Mn, Ir—Ni, Ir—Co, Ir—Cu, Ir—Ag, Ir—Pd, Ir—Au, Ir—Pt, Ir— Ru, Sn—Fe, Sn—Mn, Sn—Ni, Sn—Co, Sn—Cu, Sn—Ag, Sn—Pd, Sn—Au, Sn—Pt, Sn—Ru, Sn—Ir, In—Fe, In—Mn, In—Ni, In—Co, In—Cu, In—Ag, In—Pd, In—Au, In—Pt, In—Ru, In—Ir, In—Sn, Bi—Fe, Bi—Mn, Bi—Ni, Bi—Co, Bi—Cu, Bi—Ag, Bi—Pd, Bi—Au, Bi—Pt, Bi—Ru, Bi—Ir, Bi—Sn, Bi—In, Pb—Fe, Pb—Mn, Pb—Ni, Pb—Co, Pb—Cu, Pb—Ag, Pb—Pd, Pb—Au, Pb—Pt, Pb—Ru, Pb—Ir, Pb—Sn, Pb—In, Pb—Bi, Rh—Fe, Rh—Mn, Rh—Ni, Rh—Co, Rh—Cu, Rh—Ag, Rh—Pd, Rh—Au, Rh—Pt, Rh—Ru, Rh—Ir, Rh—Sn, Rh—In, Rh—Bi, Rh—Pb, and the like may be used.
When a manganese (Mn)-nickel (Ni) single atom dimer is used among various single atom dimers (SADs) described above, a production amount of acetone may be significantly improved as compared with other single atom dimers (SADs).
A reduced material RM of the carbon dioxide (CO2) electrochemically reduced through the cathode 320 including the catalyst in which the nitrogen-doped porous carbon is coated with the single atom metal as described above may include ethanol and acetone. In addition, the reduced material may include water (H2O), and may further include CO, HCOO—, CH4, C2H4, C2 or C3 alcohol, unreacted carbon dioxide, and the like. The reduced material RM may be discharged from the cathode module 300 and provided to the separation module 500 and the monitoring system 800, which will be described below.
The gas diffusion layer 330 may diffuse the carbon dioxide supplied to the cathode compartment 310 to the cathode 310. In addition, the gas diffusion layer 330 may effectively prevent moisture condensation so as to smoothly supply the carbon dioxide from the cathode compartment 310 to the cathode 310, so that electrolysis reaction efficiency may be improved. According to one embodiment, the gas diffusion layer 330 may include a porous body using a carbon material such as carbon fiber cloth, carbon fiber felt, or carbon fiber paper, or a metal porous body including a thin metal plate having a net structure such as an expanded metal or a metal mesh.
The cation exchange membrane 400 may provide a path through which ions may move between the anode 220 and the cathode 320. In addition, the cation exchange membrane 400 may separate the anode 220 and the cathode 320 from each other to prevent the anode 220 and the cathode 320 from making physical contact. According to one embodiment, the cation exchange membrane 400 may include a first ion conductive polymer membrane adjacent to the anode 220, and a second ion conductive polymer membrane adjacent to the cathode 320, and a discontinuous polymer interface may be formed between the first ion conductive polymer membrane and the second ion conductive polymer membrane. Accordingly, ion movement efficiency between the anode 220 and the cathode 320 may be improved, so that the electrolysis efficiency of the carbon dioxide through the cathode 320 may be improved. For example, a Nafion membrane may be used as the first ion conductive polymer membrane and the second ion conductive polymer membrane.
According to one embodiment, the anode 220, the cation exchange membrane 400, the cathode 320, and the gas diffusion layer 330 may be defined as a membrane electrode assembly (MEA). According to one embodiment, the membrane electrode assembly (MEA) may be manufactured through preparing a catalyst solution (S10), coating one side of a cation exchange membrane 400 with the catalyst solution to form a cathode 320 on the cation exchange membrane 400 (S20), arranging a gas diffusion layer 330 on the cathode 320 (S30), bonding the cathode 320 to the gas diffusion layer 330 (S40), and bonding the anode 220 to an opposite side of the cation exchange membrane 400 (S50).
In more detail, in the step S10, the catalyst solution may be prepared by mixing the catalyst (cathode catalyst) described with reference to
In the step S20, after activating the cation exchange membrane 400, the activated cation exchange membrane 400 may be coated with the catalyst solution, and the catalyst solution used for the coating may be dried to remove the binder and the solvent in the coating solution, so that the cathode 320 may be formed on the cation exchange membrane 400. For example, the activation of the cation exchange membrane 400 may be performed by immersing the cation exchange membrane 400 in the water to hydrate the cation exchange membrane 400, and drying the cation exchange membrane 400 to remove remaining water. The cation exchange membrane 400 may be defined as a membrane, and the cathode 320 may be defined as a cathode catalyst layer.
In the step S30, the gas diffusion layer (GDL) 330 may be disposed on the cathode 320, and in the step S40, the cathode 320 and the gas diffusion layer 330 may be bonded to each other by using a hot press method. For example, the hot press may be performed at a temperature of 90° C. to 135° C. for 0.5 minutes to 5 minutes.
Referring again to
The separation module 500 may separate ethanol or acetone from the reduced material RM. According to one embodiment, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a difference in solubility for salt. In other words, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a salting-out method. In more detail, when salt (e.g., NaCl) is added to the reduced material RM and mixed, since the water included in the reduced material RM has relatively high solubility for the salt, and the acetone has relatively low solubility for the salt, the water and the acetone may be separated into different phases. Accordingly, only an acetone portion may be separated while phase separation has occurred, so that the acetone may be easily separated from the reduced material RM.
Alternatively, according to another embodiment, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a difference in boiling points. In other words, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a distillation method. In more detail, since the water included in the reduced material RM has a relatively high boiling point, and the acetone has a relatively low boiling point, after heat-treating the reduced material RM at a temperature between the boiling point of the water and the boiling point of the acetone, vapor generated from the heat treatment may be collected and condensed, so that the acetone may be easily separated from the reduced material RM.
Alternatively, according to still another embodiment, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using phase separation, molecular sieve or adsorption techniques, reverse osmosis and pervaporation, and the like. A method for separating the ethanol or the acetone from the reduced material RM is not limited.
A by-product (e.g., CO2, H2O, etc.) that may be used for the electrolysis of the carbon dioxide among by-products remaining after the ethanol or the acetone is separated from the reduced material RM may be circulated and supplied from the separation module 500 to the cathode compartment 310. According to one embodiment, a third pump P3 may be disposed in a path that connects the separation module 500 and the cathode compartment 310, and a flow rate of the by-product circulated and supplied from the separation module 500 to the cathode compartment 310 may be controlled by the third pump P3.
The monitoring system 800 may receive the reduced material RM from the cathode module 300 to identify a composition of the reduced material RM. Accordingly, progress of the electrolysis of the carbon dioxide through the cathode module 300 may be recognized in real time. According to one embodiment, the monitoring system 800 may include online GC, online GC-MS, online FT-IR, portable sensors, and the like.
As a result, according to the first embodiment of the present invention, the electrolysis apparatus may include: an anode module 200 configured to electrochemically oxidize water (H2O) to generate an oxide including oxygen (O2) and hydrogen ions (protons); a cathode module 300 arranged opposite the anode module 200, and configured to electrochemically reduce carbon dioxide (CO2) to generate a reduced material including ethanol and acetone; and a separation module 500 configured to receive the reduced material from the cathode module 300, and separate the ethanol or the acetone from the reduced material. Accordingly, useful compounds such as ethanol and acetone may be easily generated from carbon dioxide.
According to one embodiment, the anode and the cathode may include one of Mn—Mn or Mn—Ni or Ni—Ni on N-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on S-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/P-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/S-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/O-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on O-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on Se-doped carbon nanotube, and Mn—Mn or Mn—Ni or Ni—Ni on N/Se-doped carbon nanotube, but are not limited thereto.
According to one embodiment, the cathode may include a mixture of cathode catalyst materials, and the mixture of the cathode catalyst materials may include one of Mn—Mn or Mn—Ni or Ni—Ni on N-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on S-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/P-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/S-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/O-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on O-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on Se-doped carbon nanotube, and Mn—Mn or Mn—Ni or Ni—Ni on N/Se-doped carbon nanotube, but is not limited thereto.
According to one embodiment, a cation exchange ionomer may include Nafion, but is not limited thereto.
According to one embodiment, the anode included in the MEA may include one of IrO2, RuO2, Pt, Ti, Pt-coated Ti, Ir-doped metal oxides, Ru-doped metal oxides, and Pt-doped metal oxides, by is not limited thereto.
According to one embodiment, the cathode included in the MEA may include one of Mn—Mn or Mn—Ni or Ni—Ni on N-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on S-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/P-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/S-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on N/O-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on O-doped carbon nanotube, Mn—Mn or Mn—Ni or Ni—Ni on Se-doped carbon nanotube, and Mn—Mn or Mn—Ni or Ni—Ni on N/Se-doped carbon nanotube, but is not limited thereto.
Referring to
The power source 100 may be for a device generating a potential difference between an anode and a cathode, and may apply a DC voltage to an anode 220 and a cathode 320, which will be described below.
The anode module 200 may include an anode compartment 210 and an anode 220. The anode compartment 210 and the anode 220 may be adjacent to each other.
An anode electrolyte AE may be supplied to the anode compartment 210 through the anode electrolyte supply module 600. In addition, water (H2O) may be supplied to the anode compartment 210. The water (H2O) may be supplied together with the anode electrolyte AE through the anode electrolyte supply module 600, or may be supplied through a separate supply module (not shown). A method for supplying the water (H2O) into the anode compartment 210 is not limited.
According to one embodiment, the anode electrolyte AE may include one of H2SO4, HNO3, HCl, and H3PO4. A type of the anode electrolyte AE is not limited. According to one embodiment, a first pump P1 may be disposed in a flow path that connects the anode compartment 210 and the anode electrolyte supply module 600, and a flow rate of the anode electrolyte AE supplied to the anode compartment 210 may be controlled through the first pump P1. In addition, as shown in
The anode 220 may electrochemically oxidize the water (H2O). According to one embodiment, the anode 220 may include a catalyst that is active in the electrolysis of the water. For example, the catalyst included in the anode 220 may include Pt, Au, Pd, Ir, Ag, Rh, Ru, Ni, Al, Mo, Cr, Cu, Ti, W, an alloy thereof, or a mixed metal oxide. In more detail, a titanium (Ti) mesh coated with platinum (Pt) may be used as the anode 220.
An oxide of the water (H2O) electrochemically oxidized through the anode 220 may include oxygen (O2) and hydrogen ions (protons). The hydrogen ions generated from the anode 220 may be moved to the cathode module 300 that will be described below. Alternatively, the oxygen (O2) generated from the anode 220 may be discharged to an outside of the anode module 200.
The cathode module 300 may include a cathode compartment 310 and a cathode 320. The cathode compartment 310 and the cathode 320 may be adjacent to each other. In addition, the cathode module 300 may be arranged opposite to the anode module 200 while being spaced apart from the anode module 200, the cation exchange membrane 400 that will be described below may be disposed between the anode module 200 and the cathode module 300, and the anode 220 and the cathode 320 may be adjacent to the cation exchange membrane 400.
A cathode electrolyte CE may be supplied to the cathode compartment 310 through the cathode electrolyte supply module 730. In addition, gaseous carbon dioxide (CO2) including humidified water may be supplied to the cathode compartment 310.
According to one embodiment, the cathode electrolyte CE may include one of NaHCO3, KHCO3, CsCO3, and LiHCO3. A type of the cathode electrolyte CE is not limited. According to one embodiment, a second pump P2 may be disposed in a flow path that connects the cathode compartment 310 and the cathode electrolyte supply module 730, and a flow rate of the cathode electrolyte CE supplied to the cathode compartment 310 may be controlled through the second pump P2. In addition, as shown in
The cathode 320 may electrochemically reduce the carbon dioxide (CO2). In more detail, a reactant (HW+CO2) supplied to the cathode compartment 310 may react with electrons (e) and the hydrogen ions moved from the anode module 200 at the cathode 320 to generate a reduced material.
According to one embodiment, the cathode 320 may include a catalyst that is active in the electrolysis of the carbon dioxide and capable of generating ethanol and acetone from the carbon dioxide. According to one embodiment, the catalyst included in the cathode 320 may be identical to the catalyst described with reference to
A reduced material RM of the carbon dioxide (CO2) electrochemically reduced through the cathode 320 including the catalyst in which the nitrogen-doped porous carbon is coated with the single atom metal as described above may include ethanol and acetone. In addition, the reduced material may include water (H2O), and may further include CO, HCOO—, CH4, C2H4, C2 or C3 alcohol, unreacted carbon dioxide, and the like. The reduced material RM may be discharged from the cathode module 300 and provided to the monitoring system 800 that will be described below.
The cation exchange membrane 400 may provide a path through which ions may move between the anode 220 and the cathode 320. In addition, the cation exchange membrane 400 may separate the anode 220 and the cathode 320 from each other to prevent the anode 220 and the cathode 320 from making physical contact. According to one embodiment, the cation exchange membrane 400 may include a first ion conductive polymer membrane adjacent to the anode 220, and a second ion conductive polymer membrane adjacent to the cathode 320, and a discontinuous polymer interface may be formed between the first ion conductive polymer membrane and the second ion conductive polymer membrane. Accordingly, ion movement efficiency between the anode 220 and the cathode 320 may be improved, so that the electrolysis efficiency of the carbon dioxide through the cathode 320 may be improved. For example, a Nafion membrane may be used as the first ion conductive polymer membrane and the second ion conductive polymer membrane.
According to one embodiment, the anode 220, the cation exchange membrane 400, and the cathode 320 may be defined as a membrane electrode assembly (MEA).
The monitoring system 800 may receive the reduced material RM from the cathode module 300 to identify a composition of the reduced material RM. Accordingly, progress of the electrolysis of the carbon dioxide through the cathode module 300 may be recognized in real time. According to one embodiment, the monitoring system 800 may include online GC, online GC-MS, online FT-IR, portable sensors, and the like.
According to one embodiment, a T-valve TV may be disposed in a path that connects the cathode module 300, the cathode electrolyte supply module 730, and the monitoring system 800, and the reduced material RM and the cathode electrolyte CE discharged from the cathode module 300 may be distributed and provided to the monitoring system 800 and the cathode electrolyte supply module 730 through the T-valve TV.
Referring to
The power source 100 may be a device for generating a potential difference between an anode and a cathode, and may apply a DC voltage to an anode 220 and a cathode 320, which will be described below.
The anode module 200 may include an anode compartment 210 and an anode 220. The anode compartment 210 and the anode 220 may be adjacent to each other.
An anode electrolyte AE may be supplied to the anode compartment 210 through the anode electrolyte supply module 600. In addition, water (H2O) may be supplied to the anode compartment 210. The water (H2O) may be supplied together with the anode electrolyte AE through the anode electrolyte supply module 600, or may be supplied through a separate supply module (not shown). A method for supplying the water (H2O) into the anode compartment 210 is not limited.
According to one embodiment, the anode electrolyte AE may include one of H2SO4, HNO3, HCl, and H3PO4. A type of the anode electrolyte AE is not limited. According to one embodiment, a first pump P1 may be disposed in a flow path that connects the anode compartment 210 and the anode electrolyte supply module 600, and a flow rate of the anode electrolyte AE supplied to the anode compartment 210 may be controlled through the first pump P1. In addition, as shown in
The anode 220 may electrochemically oxidize the water (H2O). According to one embodiment, the anode 220 may include a catalyst that is active in the electrolysis of the water. For example, the catalyst included in the anode 220 may include Pt, Au, Pd, Ir, Ag, Rh, Ru, Ni, Al, Mo, Cr, Cu, Ti, W, an alloy thereof, or a mixed metal oxide. In more detail, a titanium (Ti) mesh coated with platinum (Pt) may be used as the anode 220.
An oxide of the water (H2O) electrochemically oxidized through the anode 220 may include oxygen (O2) and hydrogen ions (protons). The hydrogen ions generated from the anode 220 may be moved to the cathode module 300 that will be described below. Alternatively, the oxygen (O2) generated from the anode 220 may be discharged to an outside of the anode module 200.
The cathode module 300 may include a first cathode compartment 310, a cathode 320, and a second cathode compartment 340. The first cathode compartment 310 and the second cathode compartment 340 may be arranged opposite to each other while being spaced apart from each other, and the cathode 320 may be disposed between the first cathode compartment 310 and the second cathode compartment 320. In addition, the cathode module 300 may be arranged opposite to the anode module 200 while being spaced apart from the anode module 200, the cation exchange membrane 400 that will be described below may be disposed between the anode module 200 and the cathode module 300, and the anode 220 and the second cathode compartment 340 may be adjacent to the cation exchange membrane 400.
Gaseous carbon dioxide (CO2) including humidified water HW may be supplied to the first cathode compartment 310 through the carbon dioxide supply module 710 and the humidified water supply module 720. In other words, the carbon dioxide may be supplied to the first cathode compartment 310 in a humidified state. As described above, when the gaseous carbon dioxide (CO2) including the humidified water HW is supplied, a large amount of carbon dioxide may be supplied as compared with a case in which carbon dioxide is supplied alone, so that electrolysis efficiency of the cathode 320 may be improved. According to one embodiment, the gaseous carbon dioxide (CO2) may be supplied from the carbon dioxide supply module 710 to the humidified water supply module 720, and the humidified water supply module 720 may perform bubbling on the gaseous carbon dioxide (CO2) and the humidified water HW and supply the gaseous carbon dioxide (CO2) and the humidified water HW to the cathode compartment 310.
The cathode 320 may electrochemically reduce the carbon dioxide (CO2). In more detail, a reactant (HW+CO2) supplied to the cathode compartment 310 may react with electrons (e−) and the hydrogen ions moved from the anode module 200 at the cathode 320 to generate a reduced material.
According to one embodiment, the cathode 320 may include a gas diffusion layer (GDL) and a catalyst. The catalyst included in the cathode 320 may be active in the electrolysis of the carbon dioxide and capable of generating ethanol and acetone from the carbon dioxide. For example, the catalyst included in the cathode 320 may be identical to the catalyst described with reference to
A reduced material RM of the carbon dioxide (CO2) electrochemically reduced through the cathode 320 including the catalyst in which the nitrogen-doped porous carbon is coated with the single atom metal as described above may include ethanol and acetone. In addition, the reduced material may include water (H2O), and may further include CO, HCOO—, CH4, C2H4, C2 or C3 alcohol, unreacted carbon dioxide, and the like. The reduced material RM may be discharged from the cathode module 300 and provided to the monitoring system 800 that will be described below.
A cathode electrolyte CE may be supplied to the second cathode compartment 340 through the cathode electrolyte supply module 730. According to one embodiment, the cathode electrolyte CE may include one of NaHCO3, KHCO3, CsCO3, and LiHCO3. A type of the cathode electrolyte CE is not limited. According to one embodiment, a second pump P2 may be disposed in a flow path that connects the second cathode compartment 340 and the cathode electrolyte supply module 730, and a flow rate of the cathode electrolyte CE supplied to the second cathode compartment 340 may be controlled through the second pump P2. In addition, as shown in
The separation module 500 may receive the reduced material RM from the cathode module 300. According to one embodiment, a T-valve TV may be disposed in a path that connects the cathode module 300, the separation module 500, and the monitoring system 800 that will be described below, and the reduced material RM discharged from the cathode module 300 may be distributed to the separation module 500 and the monitoring system 800 that will be described below by the T-valve TV.
The separation module 500 may separate ethanol or acetone from the reduced material RM. According to one embodiment, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a difference in solubility for salt. In other words, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a salting-out method. In more detail, when salt (e.g., NaCl) is added to the reduced material RM and mixed, since the water included in the reduced material RM has relatively high solubility for the salt, and the acetone has relatively low solubility for the salt, the water and the acetone may be separated into different phases. Accordingly, only an acetone portion may be separated while phase separation has occurred, so that the acetone may be easily separated from the reduced material RM.
Alternatively, according to another embodiment, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a difference in boiling points. In other words, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using a distillation method. In more detail, since the water included in the reduced material RM has a relatively high boiling point, and the acetone has a relatively low boiling point, after heat-treating the reduced material RM at a temperature between the boiling point of the water and the boiling point of the acetone, vapor generated from the heat treatment may be collected and condensed, so that the acetone may be easily separated from the reduced material RM.
Alternatively, according to still another embodiment, the separation module 500 may separate the ethanol or the acetone from the reduced material RM by using phase separation, molecular sieve or adsorption techniques, reverse osmosis and pervaporation, and the like. A method for separating the ethanol or the acetone from the reduced material RM is not limited.
A by-product (e.g., CO2, H2O, etc.) that may be used for the electrolysis of the carbon dioxide among by-products remaining after the ethanol or the acetone is separated from the reduced material RM may be circulated and supplied from the separation module 500 to the first cathode compartment 310.
The monitoring system 800 may receive the reduced material RM from the cathode module 300 to identify a composition of the reduced material RM. Accordingly, progress of the electrolysis of the carbon dioxide through the cathode module 300 may be recognized in real time. According to one embodiment, the monitoring system 800 may include online GC, online GC-MS, online FT-IR, portable sensors, and the like.
A precursor of a carbon matrix and a precursor of a single atom metal may be mixed (S1000).
According to one embodiment, the precursor of the carbon matrix and the precursor of the single atom metal may be mixed in a liquid phase, but are not limited thereto. In this case, an environment in which the two precursors are mixed may be an inside of a Trizma pre-set crystal (pH 8.5) solution, but is not limited thereto.
According to one embodiment, the precursor of the carbon matrix may include dopamine, but is not limited thereto.
The dopamine refers to an organic compound of a catecholamine series, which has a molecular formula of C8H11NO2. As will be described below, when the dopamine is injected into a Trizma pre-set crystal solution and stirred at a room temperature, the solution may be stirred by itself to form polydopamine.
According to one embodiment, the precursor of the single atomic metal may include an ion of an element selected from the group consisting of Ni, Co, Sc, Ti, V, Cr, Mn, Fe, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ag, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and combinations thereof, but is not limited thereto. In this case, the precursor of the single atom metal may include one kind of a metal ion or two kinds of metal ions depending on a structure of the single atom metal of the resulting catalyst.
Subsequently, the precursor of the carbon matrix may be self-polymerized to form a carbon polymer (S2000).
According to one embodiment, the carbon polymer may include a precursor of the single atom metal inside the carbon polymer, but is not limited thereto.
When the precursor of the carbon matrix and the precursor of the single atom metal are stirred at a room temperature, the precursor of the carbon matrix may be self-polymerized to become the carbon polymer. In this case, the precursor of the single atom metal, that is, a metal ion, may be combined with the carbon polymer.
According to one embodiment, the carbon polymer may include polydopamine, but is not limited thereto.
Regarding the above configuration, when the carbon polymer is polydopamine, the metal ion of the precursor of the single atom metal may be combined with nitrogen of the polydopamine.
Subsequently, the carbon polymer and a nitrogen source may be mixed and heat-treated (S3000).
The nitrogen source may be a material for additionally supplying nitrogen to the carbon polymer, and when only the carbon polymer is heat-treated without the nitrogen source, a catalyst including metal nanoparticles may be manufactured. The catalyst including the metal nanoparticles may have lower atomic economic feasibility and thus lower efficiency as a catalyst than a catalyst including a single atom metal.
According to one embodiment, a mass ratio of the carbon polymer and the nitrogen source may be 1:5 to 1:10, but is not limited thereto. In more detail, the mass ratio of the carbon polymer (polydopamine combined with metal ions) and the nitrogen source (e.g., dicyandiamide) may be 1:7, but is not limited thereto.
According to one embodiment, through the heat treatment, the precursor of the single atom metal may be one kind of a single atom metal or a single atom dimer in which two kinds of single atom metals are combined, but is not limited thereto.
According to one embodiment, the carbon polymer may be a carbon matrix, but is not limited thereto.
According to one embodiment, the nitrogen source may include dicyandiamide, but is not limited thereto.
For example, when a carbon polymer including polydopamine in which Mn ions and Ni ions are combined is mixed with dicyandiamide and heat-treated, the polydopamine may be converted into a form of a nitrogen-doped two-dimensional carbon matrix. In this case, the number of nitrogen may be increased as compared with the polydopamine due to the dicyandiamide, and aggregation of the Mn ions and the Ni ions may be suppressed by positions of the increased nitrogen, so that a single atom metal, that is, a Mn—Ni dimer, may be formed instead of metal nanoparticles.
According to one embodiment, a temperature of the heat treatment may be 700° C.° to 900° C., but is not limited thereto.
A cathode catalyst manufactured by the method described above may be used in a reaction for reducing carbon dioxide (CO2) to generate ethanol and acetone. In detail, in the reaction for reducing the carbon dioxide to generate the ethanol and the acetone by using the cathode catalyst, a reaction as in <Chemical Formula 1> below may occur in an anode, and a reaction as in <Chemical Formula 2> below may occur in a cathode.
8H2O—>4O2+16H++16e− <Chemical Formula 1>
3CO2+16H++16e−->CH3COCH3+5H2O <Chemical Formula 2>
Referring to
The carbon dioxide (CO2) may be supplied to a cathode. According to one embodiment, gaseous carbon dioxide (CO2) including humidified water HW may be supplied. In other words, the carbon dioxide may be supplied to the cathode in a humidified state. According to one embodiment, the cathode may include a catalyst that is active in electrolysis of the carbon dioxide and capable of generating ethanol and acetone from the carbon dioxide. The catalyst included in the cathode may be identical to the catalyst described with reference to
As a DC voltage is applied to the anode and the cathode from a power source connected to the anode and the cathode, a potential difference may be generated between the anode and the cathode. Accordingly, the water may be electrochemically oxidized through the anode, and the carbon dioxide may be electrochemically reduced through the cathode (S300). An oxide of the water electrochemically oxidized through the anode may include oxygen (O2) and hydrogen ions (protons), a reduced material of the carbon dioxide electrochemically reduced through the cathode may include ethanol and acetone, and the hydrogen ions may be moved to the cathode and used to electrochemically reduce the carbon dioxide.
The ethanol or the acetone may be separated from the reduced material of the carbon dioxide electrochemically reduced through the cathode (S400). According to one embodiment, the ethanol or the acetone may be separated from the reduced material by using a difference in solubility for salt. Alternatively, according to another embodiment, the ethanol or the acetone may be separated from the reduced material by using a difference in boiling points.
The electrolysis apparatus and the electrolysis method according to embodiments of the present invention have been described. Hereinafter, a single flow cell electrolyzer and a multi-stack flow cell electrolyzer according to an embodiment of the present invention will be described.
Referring to
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The single flow cell electrolyzer and the multi-stack flow cell electrolyzer according to the embodiment of the present invention have been described above. Hereinafter, specific experimental examples of an electrolysis apparatus and an electrolysis method according to an embodiment of the present invention will be described.
Manufacture of Electrolysis Apparatus according to Experimental Example
As shown in
The cathode catalyst used in the electrolysis apparatus according to the experimental example was prepared as follows.
After 2.5 g of Trizma pre-set crystal (pH 8.5) was dissolved in 250 ml of DI water, 10 ml of a metal salt-containing solution was added. In this case, a concentration of the metal salt-containing solution was 2 mg/ml, in which Mn(NO3)2·6H2O and Ni(NO3)2·6H2O were included in a ratio of 1:1.
Subsequently, 140 mg of dopamine hydrochloride was rapidly added, and stirred with a magnet for 24 hours.
Subsequently, filtering was performed, washing was performed twice with DI water and ethanol, and drying was performed overnight at 60° C. to obtain Mn2+-Ni2+@polydopamine.
Mn2+-Ni2+@polydopamine and dicyandiamide were mixed in a ratio of 1:7, and heat-treated in a vacuum environment at 800° C. for 2 hours at an increment of 5° C. per minute to prepare the catalyst in which the nitrogen-doped porous carbon is coated with the Mn—Ni single atom dimer (SAD).
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Although the exemplary embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to a specific embodiment, and shall be interpreted by the appended claims. In addition, it is to be understood by a person having ordinary skill in the art that various changes and modifications can be made without departing from the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2023-0113511 | Aug 2023 | KR | national |
| 10-2024-0115589 | Aug 2024 | KR | national |
