Catalyst for production of hydrogen

Description

BACKGROUND

[0001] The present development is a high efficiency catalyst for use in the water-gas-shift reaction suitable for production of hydrogen. The catalyst includes a Group VIII or Group IB metal and a transition metal promoter on a ceria-based support. The transition metal promoter is selected from the group consisting of rhenium, niobium, silver, manganese, vanadium, molybdenum, titanium, tungsten and a combination thereof. The support may further include gadolinium, samarium, zirconium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten or a combination thereof.

[0002] Large volumes of hydrogen gas are needed for a number of important chemical reactions and since the early 1940's the water-gas-shift (WGS) reaction has represented an important step in the industrial production of hydrogen. For example, the industrial scale water-gas-shift reaction is used to increase the production of hydrogen for refinery hydro-processes and for use in the production of bulk chemicals such as ammonia, methanol, and alternative hydrocarbon fuels.

[0003] The hydrogen gas is produced from the reaction of hydrocarbons with water or oxygen and from the reaction of carbon or carbon monoxide with water. The hydrocarbons are typically reacted with water and/or oxygen in the presence of supported nickel catalysts and at high temperatures to produce a combination of carbon oxides and hydrogen gas, commonly referred to as synthesis gas or syngas (see equations 1-3):

CH4+H2O CO+3H2 (1)

CnHm+n H2O n CO+(n+m/2)H2 (2)

CH4+{fraction (1/2)}O CO+2H2 (3)

[0004] Alternatively, the syngas can be produced through the gasification of coal (equation 4):

C+H2O CO+H2 (4)

[0005] In the subsequent water-gas-shift reaction (equation 5),

CO+H2O CO2 +H2Ho298=−41.1 kJ mol−1 (5)

[0006] the composition of the so-called water gas can be adjusted to the desired ratio of hydrogen and carbon monoxide. (For a more detailed review of synthesis gas generation and application, see for example E. Supp, Rohstoff Kohle, Verlag Chemie, Weinheim, New York, 136 (1978); P. N. Hawker, Hydrocarbon Processing, 183 (1982), incorporated herein by reference).

[0007] As is known in the art, the water-gas-shift reaction (equation 5) is believed to proceed either through an associative mechanism or through a regenerative mechanism. According to the associative mechanism, the active metal of the catalyst reacts with water causing the water molecule to dissociate on the metal surface into a hydroxyl group and a hydrogen atom. The hydroxyl group can then react with adsorbed carbon monoxide to generate a formate ligand. The formate ligand can decompose to release carbon dioxide leaving a hydrogen atom associated with the metal. The hydrogen from the formate can then combine with the hydrogen from the water to produce hydrogen gas (H2). According to the regenerative mechanism, water oxidizes on the active metal surface releasing hydrogen gas (H2) and leaving the oxygen associated with the metal. Adsorbed carbon monoxide can react with the metal-oxygen complex to produce carbon dioxide. (For a more detailed review of the proposed mechanisms for the water-gas-shift catalyst, see for example “Steam Effects in Three-Way Catalysis,” authored by J. Barbier Jr., and D. Duprez, Applied Catalysis B: Environmental, 4, 105 (1994) and the references cited therein, incorporated herein by reference.)

[0008] Typically, the catalysts used in the industrial scale water-gas-shift reaction include either an iron-chromium (Fe—Cr) metal combination or a copper-zinc (Cu—Zn) metal combination. The Fe—Cr oxide catalyst works extremely well in a two stage CO conversion system for ammonia synthesis and in industrial high temperature shift (HTS) converters. In the two stage ammonia synthesis Fe—Cr oxide catalyzed reaction, the catalyst is heated to temperatures ranging from about 320° C. to about 400° C. and the CO level is reduced from about 10% to about 3500±500 ppm. However, in single stage converters the Fe—Cr oxide catalysts are not as effective and the CO level is only reduced to about 1%. The industrial HTS converters—which have reactor inlet temperatures of from about 300° C. to about 380° C.— exclusively use the Fe-based catalysts because of their excellent thermal and physical stability, poison resistance and good selectivity. These attributes are especially beneficial when low steam to CO ratios are used and the formation of hydrocarbons is favored. (See K. Kochloefl, ‘Water Gas Shift and COS Removal’ in “Handbook of Heterogeneous Catalysis”, G. Ertl, H. Knözinger, and J. Weitkamp (Ed.), VCH, Ludwigshafen, 4, Chapter 3.3, pp. 1831-1843 (1997), incorporated herein by reference, for a more extensive discussion of HTS catalysts.) Typically, the commercial catalysts are supplied in the form of pellets containing 8-12% Cr2O3 and a small amount of copper as an activity and selectivity enhancer.

[0009] The copper-based catalysts function well in systems where the CO2 partial pressure can affect the catalyst performance. It is known that the CO2 partial pressure in the reacting gas exerts a retarding effect on the forward rate constant, but over copper based catalysts the effect is negligible. Therefore, copper-based catalysts demonstrate more favorable CO conversion at lower temperatures. However, the unsupported metallic copper catalysts or copper supported on Al2O3, SiO2, MgO, pumice or Cr2O3 tend to have relatively short lifespans (six to nine months) and low space velocity operation (400 to 1000 h−1). The addition of ZnO or ZnO—Al2O3 can increase the lifetime of the copper-based catalysts, but the resultant Cu—Zn catalysts generally function in a limited temperature range of from about 200° C. to about 300° C. The Cu—Zn commercial catalysts are supplied in the form of tablets, extrusions, or spheres and are usually produced by co-precipitation of metal nitrates.

[0010] Although Fe—Cr and Cu—Zn catalysts are efficient when used in a commercial syngas generation facility, they are not readily adaptable for use in stationary fuel cell power units or mobile fuel cells which generate hydrogen from natural gas or liquid fuel. For example, the catalysts used in the fuel cell reformer must have a high level of activity under high space velocity operation conditions because relatively large volumes of hydrocarbons are passed over the catalyst bed in a relatively short period of time. Moreover, the catalyst bed volume must be extremely small as compared to a commercial syngas generation facility. A typical syngas generation facility uses reformer catalyst beds having average volumes ranging from about 2 m3 to about 240 m3, whereas stationary fuel cell reformer catalyst bed volumes are around 0.1 m3 and mobile fuel cell catalyst beds have volumes of about 0.01 m3. Further, the mobile fuel cell catalyst must be capable of retaining activity after exposure to condensing and oxidizing conditions during a large number of startup and shutdown cycles, and the catalyst must not require a special activation procedure or generate substantial heat when switching from reducing to oxidizing conditions at elevated temperatures. The mobile fuel cell catalyst must also tolerate an oxygen rich atmosphere in contrast to the Cu—Zn catalysts which are pyrophoric and which require steam removal and a nitrogen blanket upon reactor shut-down to minimize condensation formation and related deactivation. Because the hydrocarbon source for fuel cells may include contaminating materials such as sulfur, the catalyst should also have a relatively high poison resistance.

SUMMARY OF THE PRESENT DEVELOPMENT

[0011] The present development is a catalyst for use in the water-gas-shift reaction. The catalyst includes a Group VIII or Group IB metal, a transition metal promoter selected from the group consisting of rhenium, niobium, silver, manganese, vanadium, molybdenum, titanium, tungsten and a combination thereof, and a ceria-based support. The support may further include gadolinium, samarium, zirconium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten or a combination thereof.

[0012] In one embodiment, the catalyst includes platinum metal and a rhenium promoter on a ceria support. More particularly, the catalyst comprises platinum at a concentration of up to about 20 wt %, rhenium at a concentration of up to about 20 wt %, and ceria at a concentration of greater than about 10 wt %. Optionally, the catalyst formulation may further include zirconia in the range of from about 0 wt % to about 90 wt %.

[0013] The present development also includes a process for preparing a platinum and rhenium promoted catalyst having a ceria support for use in the water-gas-shift reaction. In a preferred embodiment, the process involves providing “clean” precursors as starting materials in the catalyst preparation.

DESCRIPTION OF THE FIGURES

[0014]
FIG. 1 is a graphical depiction of carbon monoxide conversion versus reaction temperature for a series of catalysts prepared in accordance with the present invention, wherein the catalysts comprise a total platinum metal and rhenium metal concentration of about 4 wt % and the relative concentrations of platinum and rhenium are varied;

[0015]
FIG. 1A is a graphical depiction of carbon monoxide conversion and methane formation versus reaction temperature for a 3 wt % Pt/1 wt % Re catalyst and for a 3 wt % Pt/0 wt % Re catalyst;

[0016]
FIG. 2 is a graphical depiction of carbon monoxide conversion versus reaction temperature for a series of catalysts prepared in accordance with the present invention, wherein the catalysts comprise platinum metal concentrations of from about 0.5 wt % to about 9 wt % and the platinum to rhenium ratio is held at about 3:1;

[0017]
FIG. 3 is a graphical depiction of carbon monoxide conversion versus reaction temperature for a series of catalysts prepared in accordance with the present invention, wherein the platinum to rhenium ratio is varied; and

[0018]
FIG. 4 is a graphical depiction of carbon monoxide conversion versus reaction temperature for a series of catalysts prepared in accordance with the present invention, wherein the catalysts include platinum at about 3 wt % and essentially no rhenium and the support is varied, and the catalyst is calcined at about 500° C. for about 1 hour or for about 15 hours.

DETAILED DESCRIPTION OF THE PRESENT DEVELOPMENT

[0019] The catalyst of the present invention is intended for use as a water-gas-shift (WGS) catalyst in a reaction suitable for conversion of hydrogen for chemical processing. The catalyst composition comprises a Group VIII metal or a Group IB metal or a combination thereof, and a transition metal promoter supported on a ceria-based material. The Group VIII metal or Group IB metal or the combination thereof is preferably present at a concentration of up to about 20 wt %. The transition metal promoter is selected from the group consisting of rhenium, niobium, silver, manganese, vanadium, molybdenum, titanium, tungsten and a combination thereof, and is preferably present in the catalyst at a concentration of up to about 20 wt %. The cerium oxide support is present in the catalyst at a concentration of greater than about 10 wt %. Optionally, the support may include an additive, such as gadolinium, samarium, zirconium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten or a combination thereof, which may be added to the support at a concentration of from about 0 wt % to about 90 wt %.

[0020] As used herein, the terms “Group VIII” and “Group IB” refer to the Periodic Table of the Elements period labelling used by the Chemical Abstract Services. Alternative terminology, known in the art, includes the old IUPAC labels “Group VIIIA” and “Group IB”, respectively, and the new IUPAC format numbers “Groups 8, 9, 10” and Group 11, respectively. Further, throughout the specification a short-hand notation is used when referring to the support. Specifically, the short-hand notation can be generalized as M1aM2bOx, wherein M1 is a first metal component, M2 is a second metal component, O is oxygen; the subscripts “a” and “b” indicate the weight percent of the components M1 and M2 relative to each other within the support; and “x” is a value appropriate to balance the charge of the support. As used herein, “surface area” refers to a BET surface area or the surface area of a particle as determined by using the Brunauer, Emmett, Teller equation for mulimolcular adsorption.

[0021] The term “weight percent (wt %)” as used herein refers to the relative weight each of the above specified components contributes to the combined total weight of those components. As is known in the art, catalysts may be loaded onto a variety of substrates depending on the intended application. The present catalyst may similarly be delivered on a variety of substrates, such as monoliths, foams, spheres, or other forms as are known in the art. When delivered in these forms and for the purposes of illustration herein, unless otherwise noted, any weight added by the substrate is not included in the wt % calculations.

[0022] The present invention can be illustrated and explained through a series of examples presented herein, which are not to be taken as limiting the present invention in any regard. Examples 1 and 2 describe general catalyst preparation procedures for preparing a water-gas-shift catalyst made according to the present invention. For the purpose of the illustration, the catalyst of Example 1 or Example 1A includes 3 wt % platinum on a cerium oxide support, with the platinum precursor being chloroplatinic acid. For the purpose of the illustration, the catalyst of example 2 includes 3 wt % platinum and 1 wt % rhenium on a cerium zirconium oxide support, with the platinum precursor being chloroplatinic acid and the rhenium precursor being ammonium perrhenate. Examples 3-91 follow either the general preparation procedure described in Example 1 or Example 1A or the general preparation procedure described in Example 2, with the particular general procedure and any variations noted for the specific example(s).

EXAMPLE 1

[0023] A 100 g sample of a water-gas-shift catalyst having about 3 wt % platinum on a cerium oxide (CeO2) support is prepared by the following steps. Samples of a cerium oxide support (CeO2) having a surface area of greater than about 50 m2/g are evaluated to determine loss of ignition, x, and to establish the wetting factor, y. Approximately (100+x)g of cerium oxide is then placed in an evaporation dish and a sufficient amount of chloroplatinic acid is added to the CeO2 to deliver approximately 3% by weight platinum metal (starting with a 100 g CeO2 sample, about 3.039 g Pt must be added). For easier handling and better distribution of the platinum, the chloroplatinic acid is diluted with y g of deionized water (or other appropriate solvent) before being added to the CeO2. The platinum/CeO2 combination is stirred occasionally while drying over a steam bath to form an impregnated powder. The impregnated powder is dried in an oven set at about 100° C. for from about 4 hours to about 24 hours, and the powder is then calcined in a furnace set at from about 440° C. to about 500° C. for from about 3 hours to about 24 hours with a heating rate of about 10° C. per minute in air. The powder is then cooled by decreasing the furnace temperature at a rate of about 60° C. per minute and the powder is returned to an evaporation dish. Approximately 100 g of a catalyst having a cerium oxide support with about 3 wt % platinum metal impregnated on the support surface, a calcined Pt/CeO2 powder, is produced.

EXAMPLE 1A

[0024] A 100 g sample of a water-gas-shift catalyst having about 3 wt % platinum on a cerium oxide (CeO2) support is prepared by determining loss of ignition, x, and determining the amount of chloroplatinic acid sufficient to deliver approximately 3 wt % platinum metal as noted in Example 1. For easier handling and better distribution of the platinum, the chloroplatinic acid is diluted with y g of deionized water (or other appropriate solvent) before being added to the CeO2. The liquid and CeO2 powder are mixed together in a flask with a magnetic stir bar. The slurry is stirred vigorously. After about one hour, 1M NH4OH solution is added until the pH of the entire slurry is between 7.5 and 8.5. The slurry is allowed to stir for about 24 hours and is then filtered over Waltham #1 filter paper. The filtrate is dried at about 100° C. for about 24 hours and the resulting powder is calcined at about 500° C. for from about 2 hours to about 24 hours.

EXAMPLE 2

[0025] Samples of water-gas-shift catalysts are prepared according to the general procedure of Example 1 or Example 1A except the cerium oxide support (CeO2) is replaced with a cerium zirconium oxide (CZO) support having a stoichiometry of approximately 3 cerium:1 zirconium (Ce0.75Zr0.25O2) and having a surface area of greater than about 50 m2/g, so that a calcined Pt/CZO powder is produced. The calcined Pt/CZO powder is then subjected to a second impregnation process using ammonium perrhenate. For the second impregnation, a sufficient amount of ammonium perrhenate to deliver about 1 wt % rhenium metal (starting with a 100 g CZO sample, about 1.01 g Re must be added, which is about 1.45 g NH4ReO4 crystals) is dissolved in a sufficient quantity of deionized water to make y grams of solution. The rhenium solution is added to the calcined Pt/CZO powder, stirred over a steam bath until dry, further dried in an oven set at about 100° C. for from about 4 hours to about 24 hours, and the powder is then calcined in a furnace set at from about 440° C. to about 500° C. for from about 1 hours to about 3 hours with a heating rate of about 10° C. per minute in air. The powder is then cooled by decreasing the furnace temperature at a rate of about 60° C. per minute. Approximately 100 g of a catalyst having a cerium zirconium oxide support with about 3 wt % platinum metal and about 1 wt % rhenium metal impregnated on the support surface is produced.

[0026] The Primary Transition Metal

[0027] Catalysts designed for use in fuel cell reformer beds must have a high level of activity under high space velocity operation conditions because relatively large volumes of hydrocarbons are passed over the catalyst bed in a relatively short period of time. Moreover, the stationary and mobile fuel cell catalyst bed volume is extremely small (generally being from about 0.01 m3 to about 0.1 m3) as compared to a commercial syngas generation facility (typically from about 2 m3 to about 240 m3). Although iron-chromium (Fe—Cr) oxide catalysts and copper-zinc (Cu—Zn) catalysts work well in the large reformer beds, higher efficiency transition metals have been considered for use in the limited bed volume fuel cells. Academic studies have demonstrated that for transition metals in the metallic state, the relative activity order in the water-gas-shift reaction is Cu>Re>Ru>Ni>Pt>Os>Au>Fe>Pd>Rh>IR (see for example “Steam Effects in Three-Way Catalysis,” authored by J. Barbier Jr., and D. Duprez, Applied Catalysis B: Environmental, 4, 105 (1994) and the references cited therein, incorporated herein by reference). Hence, if the catalyst was to function in isolation and under ideal conditions, the transition metal could be selected based solely on the relative activity. However, in actual field applications the catalyst is affected by its environment. Because of this, the primary transition metal must be selected taking into consideration the relative activity of the metal and also its selectivity, its capability to retain activity after exposure to condensing and oxidizing conditions, and its stability in an oxygen-rich and/or wet environment.

[0028] In the present development, platinum functions well as a primary transition metal for the catalyst because of its efficiency in carbon monoxide elimination and in hydrocarbon oxidation. However, other metals or combinations of metals, and particularly the Group VIII and Group IB transition metals, such as iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium gold, and cadmium and rhenium may be substituted for or may be added to the platinum as appropriate to alter the equilibrium product mix.

EXAMPLES 3-19

[0029] Samples of water-gas-shift catalysts are prepared according to the general procedure of either Example 1 or Example 1A but the chloroplatinic acid is replaced by a series of different metal precursors, as indicated in Table 1, so as to deliver the specified transition metal on the support surface.

1TABLE ITransition metal andTransition metalExampleconcentrationprecursor1platinum3 wt %H2PtCl6.6H2O 1Aplatinum3 wt %H2PtCl6.6H2O3iron3 wt %Fe(NO3)3.9H2O4cobalt5 wt %Co(NO3)2.6H2O5nickel3 wt %Ni(NO3)2.6H2O6copper3 wt %Cu(NO3)2.xH2O7ruthenium3 wt %Ru(NO)(NO3)x(OH)ya8rhodium2 wt %Rh(NO3)39palladium2 wt %(NH3)4Pd(OH)210 palladium2 wt %(NH3)4Pd(NO2)211 silver5 wt %AgNO312 osmium3 wt %OsO4 solution13 iridium2 wt %H2IrCl614 platinum1 wt %H2PtCl6.6H2O15 platinum1 wt %(NH3)4Pt(OH)216 platinum3 wt %(NH3)4Pt(OH)217 gold5 wt %[H3O]+[AuCl4]−.3H2O18 rhenium4 wt %NH4ReO419 cadmium2 wt %Cd(NO3)3.4H2Oawherein x + y = 3

[0030] The primary transition metal—as a single metal or as a combination of metals—may be present in the catalyst composition at a concentration of up to about 20 wt %, including the weight of the primary transition metal. The concentration selected is dependent on the anticipated reaction conditions and the desired product mixture, and may be optimized using known experimental procedures, such as performance versus concentration studies, as are known in the art.

[0031] The Transition Metal Promoter

[0032] It is known in the art that promoters may be added to a catalyst formulation to improve selected properties of the catalyst or to modify the catalyst activity and/or selectivity. Because fuel cell reformer beds must have a high level of activity under high space velocity operation, judicial selection of the promoter can produce a highly efficient catalyst at a relatively low cost. In the present invention, the primary transition metal and the transition metal promoters—individually or in combination—may be select as desired and as appropriate to alter the equilibrium product mix. Preferably, the transition metal promoter is selected from the group consisting of lithium, potassium, rubidium, cesium, titanium, vanadium, niobium, molybdenum, tungsten, manganese, rhenium, ruthenium, rhodium, iridium, silver, the Group VIII metals, the Group IB metals and a combination thereof.

[0033] When platinum is selected as the primary transition metal, rhenium is a particularly effective promoter for the conversion of carbon monoxide. However, other transition metal promoters may be substituted for or may be added to the rhenium as warranted by the reaction conditions. Further, when a primary transition metal other than platinum is selected, the optimum promoter may be rhenium, or rhenium used in combination with another transition metal promoter, or one or more of the other transition metal promoters as appropriate for the specific application.

[0034] The transition metal promoter is present in the water-gas-shift catalyst of the present invention at a concentration of up to about 20 wt %, including the weight of the promoter. The concentration used is dependent on the transition metal promoter selected, the primary transition metal used, the concentration of the primary transition metal, and upon the anticipated reaction conditions.

EXAMPLES 20-35

[0035] Platinum impregnated water-gas-shift catalysts are prepared according to the general procedure of Example 1. A promoter is then added to the platinum impregnated catalyst following the procedure generally outlined in Example 2 except that the ammonium perrhenate is replaced by the designated promoter precursor, as indicated in Table II, to deliver the desired promoter to the catalyst surface.

2TABLE IIPrimary transitionExamplemetal, concentrationPromoter, concentrationPromoter precursor20platinum1 wt %lithium 10 wt %Li2CO321platinum1 wt %potassium 20 wt %K2CO322platinum3 wt %rubidium 2 wt %Ru2CO323platinum5 wt %cesium 1 wt %Cs2CO324platinum3 wt %titanium 2 wt %Ti[OCH(CH3)2]425platinum3 wt %vanadium 2 wt %VO(SO4).xH2O26platinum3 wt %niobium 2 wt %NbCl527platinum3 wt %molybdenum 2 wt %MoCl528platinum3 wt %tungsten 2 wt %WCl629platinum3 wt %manganese 2 wt %MnNO330platinum1 wt %rhenium 3 wt %NH4ReO431platinum3 wt %rhenium 1 wt %NH4ReO432platinum1 wt %ruthenium0.3 wt %Ru(NO)(NO3)x(OH)ya33platinum1.6 wt % rhodium0.4 wt %Rh(NO3)334platinum3 wt %iridium 2 wt %H2IrCl635platinum3 wt %silver 2 wt %AgNO3awherein x + y = 3

[0036] Because the promoter is used in combination with the primary transition metal, the concentration of the promoter may be evaluated in terms of its weight percent contribution to the catalyst or in relative terms as compared to the primary transition metal. For example, for a water-gas-shift catalyst including a primary transition metal of 3 wt % platinum and a promoter of 1 wt % rhenium, the efficiency of the catalyst for carbon monoxide conversion over the temperature range of from about 200° C. to about 400° C. may be affected by the catalyst having a total metal concentration of about 4 wt % and/or by the catalyst including 1 wt % rhenium in the composition and/or by the catalyst having a platinum metal to rhenium metal ratio of about 3:1.

EXAMPLES 36-41

[Pt]+[Re] Held at About 4 wt %; Addition of Re

[0037] A series of water-gas-shift catalysts are prepared according to the general procedure of Example 2 except that a zirconium oxide (ZrO2) support is substituted for the cerium zirconium oxide support, and the amount of platinum and rhenium are varied relative to each other while the total non-support metal concentration is held at about 4 wt % (except for Example 41 which has a metal concentration of about 3 wt %). Examples 40 and 41 followed the general procedure of Example 1 or Example 1A.

3TABLE IIIExamplePt concentrationRe concentration[Pt]/[Re]360 wt %4 wt %0371 wt %3 wt %0.3382 wt %2 wt %1393 wt %1 wt %3404 wt %0 wt %—413 wt %0 wt %—

[0038] As shown in FIG. 1, when the metal concentration is held constant at about 4 wt %, the higher the platinum concentration relative to the rhenium concentration, the greater the conversion of carbon monoxide at relatively low termperatures. Such results are contradictory to what would be predicted solely based on the relative activity order (Cu>Re>Ru>Ni>Pt>Os>Au>Fe>Pd>Rh>Ir, Applied Catalysis B: Environmental, 4, 105 (1994). The reference article only discusses the relative activity order with respect to feeds containing CO and water, not the typical syngas feeds which contain CO2 and H2.). However, rhenium does effectively promote the platinum activity in the water gas shift reaction, particularly with respect to carbon monoxide conversion. As shown in FIG. 1, the 3 wt % platinum catalyst is more efficient with respect to carbon monoxide conversion when it is promoted with rhenium (Example 39, 3 wt % Pt/1 wt % Re) than when rhenium is absent (Example 41, 3 wt % Pt/0 wt % Re). An undesirable byproduct of the water-gas-shift reaction is methane. Thus, while it is desirable to increase the rate of carbon monoxide conversion, it is also desirable to minimize the rate of methane formation. As shown in FIG. 1A, some methane is produced starting at about 350° C. using the 3 wt % Pt/1 wt % Re catalyst. However, as shown by comparing the activity of the 3 wt % Pt/0 wt % Re catalyst to the 3 wt % Pt/1 wt % Re catalyst, when rhenium is used in combination with the platinum in the water-gas-shift catalyst, the amount of methane formed is significantly reduced.

EXAMPLES 24-50

[Pt]:[Re]Held at about 3:1

[0039] Samples of water-gas-shift catalysts are prepared according to the general procedure of Example 2 except that chloroplatinic acid is replaced by platinum tetra-amine hydroxide and, as shown in Table IV, the amount of platinum tetra-amine hydroxide and the amount of ammonium perrhenate added to the composition are varied while maintaining a platinum to rhenium ratio of about 3:1.

4TABLE IVExamplePt concentrationRe concentration[Pt]:[Re]420.5 wt %0.167 wt %3:1431.0 wt % 0.33 wt %3:1442.0 wt % 0.67 wt %3:145 3 wt % 1 wt %3:146 6 wt % 2 wt %3:147 9 wt % 3 wt %3:148 12 wt % 4 wt %3:149 15 wt % 5 wt %3:150 21 wt % 7 wt %3:1

[0040]
FIG. 2 shows the carbon monoxide conversion activity and the methane formation over the temperature range of from about 200° C. to about 450° C. for the catalysts prepared according to Examples 42-46. When the [Pt]:[Re] is held at about 3:1, the carbon monoxide conversion increases as the metal concentrations increase over the reaction temperature range of from about 200° C. to about 300° C. The benefits of the higher metal concentrations are particularly evident in the temperature range of from about 205° C. to about 225° C.

[0041] Further as shown in FIG. 2, some methane is produced starting at about 350° C. using the platinum/rhenium catalysts having a [Pt]:[Re] of about 3:1. However, the overall methane formation remains extremely low even at a platinum concentration of about 3 wt %.

EXAMPLES 51-61

[Pt]:[Re] Varied from about 1:1. to about 9:1

[0042] A series of water-gas-shift catalysts are prepared according to the general procedure of Example 2 except that the chloroplatinic acid is replaced by platinum tetra-amine hydroxide, and the amount of platinum tetra-amine hydroxide and the ammonium perrhenate are varied as necessary to deliver the platinum metal and rhenium concentrations as shown in Table V. Examples 51 and 52 are prepared according to the general procedure of Example 1 or Example 1A with platinum tetra-amine hydroxide replacing the chloroplatinic acid and the cerium zirconium oxide replacing the CeO2 support.

5TABLE VExamplePt concentrationRe concentration[Pt]/[Re]51 3 wt % 0 wt %—523.5 wt % 0 wt %—53 3 wt % 3 wt %154 3 wt % 2 wt %1.555 3 wt % 1.5 wt %256 3 wt % 1 wt %3573.2 wt % 0.8 wt %458 6 wt % 1 wt %659 3 wt %0.43 wt %7603.5 wt % 0.5 wt %761 9 wt % 1 wt %9

[0043]
FIG. 3 shows the carbon monoxide conversion at two typical reaction temperatures (204° C., 225° C.,) for catalysts having about 3 wt % platinum and having [Pt]:[Re] varying from about 1:1 to about 7:1. As shown in FIG. 3, the carbon monoxide conversion increases as the platinum to rhenium ratio increases from about 1:1 to about 3:1. The enhanced performance for the 3:1 [Pt]:[Re] catalyst as compared to the 7:1 catalyst may be due to a number of factors. For example, holding platium at about 3 wt % forces the 7:1 catalyst to have a rhenium concentration of about 0.43 wt %, which may indicate that the absolute rhenium concentration is insuffient to function as an optimum promoter.

[0044] The Support

[0045] The water-gas-shift catalyst support of the present invention comprises a ceria-based material that is present at a concentration of greater than about 10 wt %. Cerium oxide is generally recognized as an efficient support for water-gas-shift catalysts because ceria can essentially function as a promoter. For example, in general, precious metals such as platinum, rhodium and palladium are not good water gas shift catalysts because they are not easily oxidized by water. However, it has been shown that when these metals are ceria supported, they are active shift catalysts. The activity is believed to result from the thermodynamically favorable oxidation of Ce2O3 by water to produce two moles CeO2 and hydrogen. The CeO2 can then transfer oxygen to the transition metal to react with CO adsorbed on the metal thereby enhancing the activity of the metal. (For a more extensive discussion of water-gas-shift catalysts, see for example “Studies of the Water-Gas-Shift Reaction on Ceria-Supported Pt, Pd, and Rh: Implications for Oxygen-Storage Properties,” T. Bunluesin, R. J. Gorte, and G. W. Graham, Applied Catalysis B: Environmental, 15, 107 (1998) and the references cited therein, and “A Comparative Study of Water-Gas-Shift Reaction Over Ceria Supported Metallic Catalysts” S. Hilaire, X. Wang, T. Luo, R. J. Gorte, and J. P. Wagner, Applied Catalysis A: General, 215, 271 (2001) and the references cited therein, incorporated herein by reference.) Further, the cerium oxide has a surface area of from about 10 m2/g to about 200 m2/g and a crystallite size range which appears to facilitate the water-gas-shift reaction.

[0046] The water-gas-shift reaction, and particularly the CO conversion, can also be affected by the inclusion of additives to the cerium oxide. To enhance the CeO2 performance, additives such as gadolinium, samarium, zirconium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten or a combination thereof may be used in the ceria-based support, such as shown in Table VI. The additive is generally present at a concentration of from about 0 wt % to about 90 wt %. Although the cerium based supports are preferred for the present invention, non-cerium based supports known in the art can also be used to deliver the Group VIII or Group IB metal and the transition metal promoter.

EXAMPLES 62-69

[0047] Samples of water-gas-shift catalysts are made according to the general procedure of Example 2 except that the cerium oxide support is substituted with the support material noted in Table VI for the particular example.

6TABLE VIExampleSupport62Ce0.7Gd0.2Zr0.1Ox63Ce0.7Sm0.2Zr0.1Ox64Ce0.6Mn0.4O265cerium metal66CeO2/Al2O36720% ZrO2/80% TiO26850% ZrO2/50% TiO26980% ZrO2/20% TiO2

[0048] Mixed cerium zirconium oxide is a preferred support for the platinum/rhenium containing catalyst. The cerium to zirconium ratio can be varied as necessary to optimize the catalyst performance. In the present development using a platinum primary metal and a rhenium promoter, it has been found that a cerium zirconium oxide support which is rich in cerium, i.e. in which the weight percent added to the support by the cerium is greater than the weight percent added to the support by the zirconium, demonstrates a surprisingly improved level of CO conversion without concommitant significant methane formation. For example, for the catalyst comprising about 3 wt % platinum and about 1 wt % rhenium, a preferred support is Ce0.8Zr0.2O2 having a surface area greater than about 30 m2/g, and preferably having a surface area of from about 50 m2/g to about 150 m2/g. Further it is preferred that the support be essentially absent of known catalytic poisons, such as sulfur, which are known in the art.

EXAMPLES 70-76

[0049] Samples of water-gas-shift catalysts are prepared according to the general procedure of Example 1 or Example 1A except that the cerium oxide support is substituted with the support material noted in Table VII for the particular example.

EXAMPLES 77-85

[0050] Samples of water-gas-shift catalysts are prepared according to the general procedure of Example 2 except that the cerium zirconium oxide support is substituted with the support material noted in Table VII for the particular example.

7TABLE VIIExamplePt concentrationRe concentrationSupport703 wt %0 wt %CeO2713 wt %0 wt %Ce0.8Zr0.2O2723 wt %0 wt %Ce0.75Zr0.25O2733 wt %0 wt %Ce0.7Zr0.3O2743 wt %0 wt %Ce0.5Zr0.5O2743 wt %0 wt %ZrO2766 wt %0 wt %Ce0.75Zr0.25O2773 wt %1 wt %CeO2783 wt %1 wt %Ce0.9Zr0.1O2793 wt %1 wt %Ce0.8Zr0.2O2803 wt %1 wt %Ce0.75Zr0.25O2813 wt %1 wt %Ce0.7Zr0.3O2823 wt %1 wt %Ce0.5Zr0.5O2833 wt %1 wt %Ce0.2Zr0.8O2843 wt %1 wt %ZrO2856 wt %1 wt %Ce0.75Zr0.25O2

[0051] Precursor Ligands and Catalyst Preparation

[0052] The preparation method can affect the performance of the water-gas-shift catalyst. For example, as is known in the art, the primary transition metal(s) and the transition metal promoter are generally provided in the form of a metal-based precursor for impregnation on a support material. The metal-based precursor generally includes one or more substituents or ligands which separate from the metal when the metal is impregnated on the support material. Although the ligands of the precursor are not believed to be active materials of the finished catalyst, they may affect how the support receives the transition metal and/or the promoter. Further, as is known in the art, certain ligands or substituents may negatively affect the support surface and may effectively “poison” the catalyst.

[0053] In the present development, the primary transition metal and the promoter are preferably based on clean precursors, wherein the term “clean” refers to a precursor which does not include one or more potentially catalytically poisonous substituents or to a precursor from which the potentially catalytically poisonous substituents can be removed with relative ease during the catalyst preparation process. As is known in the art, a potentially poisonous substituent is any element which can adsorb to the support surface in such a manner so as to prevent one or more sites on the support surface from participating in the desired catalytic reaction. For water-gas-shift catalysts, some commonly recognized poisons are sulfur, chlorine, sodium, bromine, iodine or combinations thereof. Depending on the particular support material selected, other substituents may be included in the list of potential poisons based on their reactivity.

[0054] In the present development, some representative “clean” precursors would include complexes having ligands selected from the group consisting of ammonia, primary amines, secondary amines, tertiary amines, quaternary amines, nitrates, nitrites, hydroxyl groups, carbonyls, carbonates, aqua ions, oxides, oxylates, and combinations thereof. For example, for the platinum containing catalysts, the platinum may be delivered to the support in the form of a platinum tetra-amine hydroxide solution, a platinum tetra-amine nitrate, a platinum di-amine nitrate, platinum oxalate, platinum nitrate or other similar platinum-based complexes. When the platinum is delivered to the support in the form of the platinum tetra-amine hydroxide solution the resultant water-gas-shift catalyst has a slightly greater carbon monoxide conversion profile than when other precursor materials are used. Similarly, the rhenium may be provided as a clean precursor in the form of ammonium perrhenate or as one of the known rhenium oxide complexes, such as ReO2, ReO3 or Re2O7.

[0055] Alternatively, the primary transition metal precursor and the promoter precursor may include substituents which may potentially be poisonous to the catalyst, but which can be removed with relative ease during the catalyst production process to a sufficient extent so as to make the catalyst “clean.” For example, as indicated in Example 1 or Example 1A and several related examples herein, chloroplatinic acid may be used as a platinum source with the chlorine being removed by air calcination. Depending on the concentration of chlorine present in the catalyst following calcination, the catalyst may be washed by various methods known in the art such as water washing, washing with basic solution, steam calcination, reducing the catalyst with hydrogen and/or other reducing agents followed by washing.

[0056] As is known in the art, catalysts are frequently calcined to drive off volatile matter or to effect changes in the catalyst. The calcination time and temperature can affect the catalyst performance, and it is recommended that the calcination conditions be optimized for the particular desired catalyst composition and intended use. In the present invention, the catalyst is calcined after the primary transition metal is added to the support. When the primary transition metal is platinum which is delivered to the catalyst in the form of chloroplatinic acid, and the support comprises ceria, the catalyst is calcined in a furnace set at from about 440° C. to about 500° C. for from less than about 1 hour to greater than about 16 hours with a heating rate of about 10° C. per minute in air. If a transition metal promoter is added to the primary transition metal catalyst, the catalyst is calcined after the addition of the promoter in a furnace set at from about 440° C. to about 500° C. for from less than about 1 hour to greater than about 3 hours with a heating rate of about 10° C. per minute in air.

EXAMPLES 86-91

[0057] Samples of water-gas-shift catalysts are prepared according to the general procedure of Example 1 or Example 1A and are calcined at about 500° C. for either about 1 hour or for about 15 hours as noted in Table VIII. Examples 88-89 vary from Example 1 or Example 1A by having a zirconium oxide support substituted for the cerium oxide support. Examples 90-91 vary from Example 1 or Example 1A by having a cerium zirconium oxide support substituted for the cerium oxide support.

8TABLE VIIICalcinationReTime,ResidualExamplePt conc.conc.SupportTempChlorine863 wt %0 wt %CeO2500° C., 12.0%hour873 wt %0 wt %CeO2500° C., 150.6%hours883 wt %0 wt %ZrO2500° C., 10.8%hour893 wt %0 wt %ZrO2500° C., 150.2%hours903 wt %0 wt %Ce0.8Zr0.2O2500° C., 11.6%hour913 wt %0 wt %Ce0.8Zr0.2O2500° C., 150.6%hours

[0058] As shown in FIG. 4, for catalysts having about 3 wt % platinum and having a cerium oxide support, the carbon monoxide conversion is improved by calcining the catalyst for about 15 hours as compared to calcining the catalyst for about 1 hour. In contrast, essentially no improvement in CO conversion is observed for zirconium oxide supported catalysts as the calcination time is lengthened. However, when the support includes both cerium and zirconium, longer calcination times result in improved CO conversion similar to that observed for the cerium oxide supported catalysts.

[0059] The catalyst may be delivered on substrates other than monoliths, foams, spheres, or similar substrates. For example, the present catalyst may be delivered in the form of extrudates, tabs, pellets, multi-passage substrates or similarly prepared materials. When delivered in these forms, the catalytic activity is dependent on the relative amounts of the active components on the substrate surface because it is essentially only the surface components which can participate in the water-gas-shift reaction. As is known in the art, when delivered in these alternative forms, the concentration of the components is more accurately referred to in terms of the surface concentration or in grams of specific metal per liter of catalyst.

[0060] There are numerous ways in which metals can be combined with supports to produce catalysts. In the examples presented herein, the metals have been combined with the support using known impregnation techniques. However, other methods may be used, such as co-precipitation, sol-gel, vapor deposition, chemical vapor deposition, deposition precipitation, sequential precipitation, mechanical mixing, decomposition and other methods which are known in the art. Any means for combining metals with a support to produce a catalyst which has the composition described herein is believed to fall within the scope of this invention.

[0061] On-Stream Performance

[0062] Like all catalysts, the water-gas-shift catalyst itself is not permanently altered in the water-gas-shift reaction. However, over time the catalyst efficiency can be diminished by contamination of the active sites, for example, by deposition of carbon or other contaminants in the material feed, thus requiring the catalyst bed to be cleaned or regenerated. Because fuel cells, and particularly mobile fuel cells, are being considered for use in consumer vehicles, proper routine maintenance may be difficult to ensure. Thus, a desirable water-gas-shift catalyst should be able to remain on stream for an extended period between catalyst regeneration.

[0063] The primary transition metal, promoter and support affect the on-stream performance, and may be combined to optimize the on-stream performance as desired. In the present development, the platinum on a cerium zirconium oxide support performs adequately for extended periods on-stream and following regeneration. However, the addition of rhenium significantly improves the on-stream performance before, and particularly following, the regeneration cycles.

[0064] It is understood that variations may be made which would fall within the scope of this development. For example, precursor materials other than those expressly listed may be employed to deliver the desired primary transition metal(s) and/or the promoter(s), or the processing conditions may be varied without exceeding the scope of this development. Further, the active catalyst may be delivered in a form that includes essentially inert components. In the latter case, the inert components should be disregarded in any calculations when determining the relative weight percentages of the active components.

Claims

1. A catalyst suitable for production of hydrogen, said catalyst comprising: a. a primary transition metal selected from the group consisting of a Group VIII metal, a Group IB metal, cadmium and a combination thereof; b. a transition metal promoter; and c. a support material comprising cerium oxide, wherein said transition metal and said promoter are combined with said support material to form said catalyst.
2. The catalyst of claim 1 wherein said primary transition metal is present at a concentration of up to about 20 wt %.
3. The catalyst of claim 2 wherein said primary transition metal is selected from the group consisting of iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, cadmium and a combination thereof.
4. The catalyst of claim 1 wherein said promoter is present at a concentration of up to about 20 wt %.
5. The catalyst of claim 4 wherein said promoter is selected from the group consisting of lithium, potassium, rubidium, cesium, titanium, vanadium, niobium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, and a combination thereof.
6. The catalyst of claim 1 wherein said support material comprises cerium oxide at a concentration of greater than about 10 wt %.
7. The catalyst of claim 1 wherein said support material has a surface area of from about 10 m2/g to about 200 m2/g.
8. The catalyst of claim 1 wherein said support material further includes an additive selected from the group consisting of gadolinium, samarium, zirconium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten and a combination thereof.
9. The catalyst of claim 8 wherein said support material comprises said additive at a concentration of from about 0 wt % to about 90 wt %.
10. The catalyst of claim 1 wherein said support material further includes zirconium.
11. The catalyst of claim 10 wherein said zirconium is present in said catalyst at a concentration of from about 0 wt % to about 90 wt %.
12. The catalyst of claim 1 wherein said support material is a mixed cerium zirconium oxide.
13. The catalyst of claim 12 wherein said mixed cerium zirconium oxide comprises cerium at a higher weight percent than zirconium.
14. The catalyst of claim 12 wherein said cerium zirconium oxide has a surface area of from about 30 m2/g to about 150 m2/g.
15. The catalyst of claim 1 wherein said primary transition metal is combined with said support material by subjecting a predetermined amount of said support material to a solvent containing a predetermined concentration of a first transition metal precursor, and evaporating said solvent to form a transition metal inclusive support.
16. The catalyst of claim 15 wherein said first transition metal precursor is a transition metal complex having at least one ligand and wherein said ligand is absent of sulfur, chlorine, sodium, bromine, and iodine.
17. The catalyst of claim 15 wherein said first transition metal precursor is a transition metal complex having ligands selected from the group consisting of ammonia, primary amines, secondary amines, tertiary amines, quaternary amines, nitrates, nitrites, hydroxyl groups, carbonyls, carbonates, aqua ions, oxides, oxylates, and combinations thereof.
18. The catalyst of claim 15 wherein said first transition metal precursor is selected from the group consisting of platinum tetra-amine hydroxide, platinum tetra-amine nitrate, platinum di-amine nitrate, platinum oxalate, platinum nitrate and a combination thereof.
19. The catalyst of claim 15 wherein said transition metal inclusive support is calcined.
20. The catalyst of claim 15 wherein said promoter is combined with said transition metal inclusive support by subjecting a predetermined amount of said transition metal inclusive support to a solvent containing a predetermined concentration of said a second transition metal precursor, and evaporating said solvent to form said catalyst.
21. The catalyst of claim 20 wherein said second transition metal precursor is a transition metal complex having at least one ligand and wherein said ligand is absent of sulfur, chlorine, sodium, bromine, and iodine.
22. The catalyst of claim 20 wherein said second transition metal precursor is selected from the group consisting of ammonium perrhenate, a rhenium oxide complex, ReO2, ReO3 or Re2O7.
23. The catalyst of claim 20 wherein said catalyst is calcined.
24. The catalyst of claim 1 wherein said transition metal promoter is combined with said support material by subjecting a predetermined amount of said support material to a solvent containing a predetermined concentration of a first transition metal precursor, and evaporating said solvent to form a promoter inclusive support.
25. The catalyst of claim 24 wherein said promoter inclusive support is combined with said primary transition metal by subjecting a predetermined amount of said promoter inclusive support to a solvent containing a predetermined concentration of said a second transition metal precursor, and evaporating said solvent to form said catalyst.
26. The catalyst of claim 1 wherein said primary transition metal and said transition metal promoter are combined with said support by co-dissolving said primary transition metal and said promoter with said support.
27. The catalyst of claim 1 wherein said catalyst is combined with a substrate, wherein said substrate is a monolith, a foam, a sphere, an extrudate, a tab, a pellet, a multi-passage substrate or a combination thereof.
28. A catalyst suitable for conversion of hydrogen, said catalyst comprising: a. a primary transition metal present at a concentration of up to about 20 wt % and selected from the group consisting of iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, cadmium and a combination thereof; b. a transition metal promoter present at a concentration of up to about 20 wt % and selected from the group consisting of lithium, potassium, rubidium, cesium, titanium, vanadium, niobium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, and a combination thereof; and c. a support material comprising cerium oxide at a concentration of greater than about 10 wt %, wherein said transition metal and said promoter are combined with said support material to form said catalyst.
29. The catalyst of claim 28 wherein said support material further includes an additive selected from the group consisting of gadolinium, samarium, zirconium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten and a combination thereof.
30. The catalyst of claim 29 wherein said additive is present at a concentration of from about 0 wt % to about 90 wt %.
31. The catalyst of claim 28 wherein said support material further includes zirconium and said zirconium is present in said catalyst at a concentration of from about 0 wt % to about 90 wt %.
32. The catalyst of claim 28 wherein said support material is a mixed cerium zirconium oxide.
33. The catalyst of claim 32 wherein said mixed cerium zirconium oxide comprises cerium at a higher weight percent than zirconium.
34. The catalyst of claim 28 wherein said primary transition metal is combined with said support material by subjecting a predetermined amount of said support material to a solvent containing a predetermined concentration of a first transition metal precursor, and evaporating said solvent to form a transition metal inclusive support.
35. The catalyst of claim 34 wherein said first transition metal precursor is a transition metal complex having at least one ligand and wherein said ligand is absent of sulfur, chlorine, sodium, bromine, and iodine.
36. The catalyst of claim 34 wherein said first transition metal precursor is a transition metal complex having ligands selected from the group consisting of ammonia, primary amines, secondary amines, tertiary amines, quaternary amines, nitrates, nitrites, hydroxyl groups, carbonyls, carbonates, aqua ions, oxides, oxylates, and combinations thereof.
37. The catalyst of claim 34 wherein said first transition metal precursor is selected from the group consisting of platinum tetra-amine hydroxide, platinum tetra-amine nitrate, platinum di-amine nitrate, platinum nitrate, platinum oxalate and a combination thereof.
38. The catalyst of claim 34 wherein said transition metal inclusive support is calcined.
39. The catalyst of claim 34 wherein said promoter is combined with said transition metal inclusive support by subjecting a predetermined amount of said transition metal inclusive support to a solvent containing a predetermined concentration of a second transition metal precursor, and evaporating said solvent to form said catalyst.
40. The catalyst of claim 41 wherein said second transition metal precursor is a transition metal complex having at least one ligand and wherein said ligand is absent of sulfur, chlorine, sodium, bromine, and iodine.
41. The catalyst of claim 39 wherein said second transition metal precursor is selected from the group consisting of ammonium perrhenate, a rhenium oxide complex, ReO2, ReO3 or Re2O7.
42. The catalyst of claim 39 wherein said catalyst is calcined.
43. The catalyst of claim 28 wherein said catalyst is combined with a substrate, wherein said substrate is a monolith, a foam, a sphere, an extrudate, a tab, a pellet, a multi-passage substrate or a combination thereof.
44. A catalyst suitable for conversion of hydrogen, said catalyst comprising: a. a primary transition metal present at a concentration of up to about 20 wt % and selected from the group consisting of iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, cadmium and a combination thereof; b. a transition metal promoter present at a concentration of up to about 20 wt % and selected from the group consisting of lithium, potassium, rubidium, cesium, titanium, vanadium, niobium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, and a combination thereof; and c. a support material comprising a mixed cerium zirconium oxide which is present at a concentration of greater than about 10 wt %, wherein said transition metal and said promoter are combined with said support material to form said catalyst.
45. The catalyst of claim 44 wherein said support material further includes an additive present at a concentration of from about 0 wt % to about 90 wt % and selected from the group consisting of gadolinium, samarium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten and a combination thereof.
46. The catalyst of claim 44 wherein said primary transition metal is impregnated on said support material by subjecting a predetermined amount of said support material to a solvent containing a predetermined concentration of a first transition metal precursor, evaporating said solvent to form a transition metal inclusive support and calcining said transition metal inclusive support, and said promoter is impregnated on said transition metal inclusive support by subjecting a predetermined amount of said transition metal inclusive support to a solvent containing a predetermined concentration of said a second transition metal precursor, evaporating said solvent to form said catalyst.
47. The catalyst of claim 44 wherein said first transition metal precursor is a transition metal complex having at least one ligand and wherein said ligand does not include sulfur, chlorine, sodium, bromine, iodine or combinations thereof, and wherein said second transition metal precursor is a transition metal complex having at least one ligand and wherein said ligand does not include sulfur, chlorine, sodium, bromine, iodine or combinations thereof.
48. The catalyst of claim 44 wherein said first transition metal precursor is selected from the group consisting of platinum tetra-amine hydroxide, platinum tetra-amine nitrate, platinum di-amine nitrate, platinum oxalate, platinum nitrate and a combination thereof.
49. The catalyst of claim 44 wherein said first transition metal precursor is a transition metal complex having ligands selected from the group consisting of ammonia, primary amines, secondary amines, tertiary amines, quaternary amines, nitrates, nitrites, hydroxyl groups, carbonyls, carbonates, aqua ions, oxides, oxylates, and combinations thereof.
50. The catalyst of claim 44 wherein said second transition metal precursor is selected from the group consisting of ammonium perrhenate, a rhenium oxide complex, ReO2, ReO3 or Re2O7.
51. The catalyst of claim 44 wherein said catalyst is calcined.
52. A method for preparing a catalyst suitable for conversion of hydrogen for chemical processing, said method comprising: a. impregnating a primary transition metal selected from the group consisting of iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, cadmium and a combination thereof onto a support material comprising cerium oxide to form a transition metal inclusive support, and calcining said inclusive support; and b. impregnating a transition metal promoter selected from the group consisting of lithium, potassium, rubidium, cesium, titanium, vanadium, niobium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, and a combination thereof onto said support material to form said catalyst, and calcining said promoter inclusive catalyst.
53. The catalyst of claim 52 wherein said primary transition metal is delivered to said support as a solvent containing a predetermined concentration of a first transition metal precursor defined as a transition metal complex having at least one ligand and wherein said ligand is absent of sulfur, chlorine, sodium, bromine, and iodine, and wherein said promoter is delivered to said transition metal inclusive support as a solvent containing a predetermined concentration of said a second transition metal precursor defined as a transition metal complex having at least one ligand and wherein said ligand is absent of sulfur, chlorine, sodium, bromine, and iodine.
54. The catalyst of claim 52 wherein said primary transition metal is present at a concentration of up to about 20 wt %, said promoter is present at a concentration of up to about 20 wt %, and said cerium oxide is present at a concentration of greater than about 10 wt %
55. The catalyst of claim 52 wherein said support material further includes an additive present at a concentration of from about 0 wt % to about 90 wt % and selected from the group consisting of gadolinium, samarium, zirconium, lithium, cesium, lanthanum, praseodymium, manganese, titanium, tungsten and a combination thereof.
56. The catalyst of claim 52 wherein said first transition metal precursor is a transition metal complex having ligands selected from the group consisting of ammonia, primary amines, secondary amines, tertiary amines, quaternary amines, nitrates, nitrites, hydroxyl groups, carbonyls, carbonates, aqua ions, oxides, oxylates, and combinations thereof.
57. The catalyst of claim 52 wherein said first transition metal precursor is selected from the group consisting of platinum tetra-amine hydroxide, platinum tetra-amine nitrate, platinum di-amine nitrate and a combination thereof, and said promoter precursor wherein said second transition metal precursor selected from the group consisting of ammonium perrhenate, a rhenium oxide complex, ReO2, ReO3 or Re2O7.

Catalyst for production of hydrogen

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