EP2337630A1

EP2337630A1 - Method for continuously producing a catalyst

Info

Publication number: EP2337630A1
Application number: EP09781982A
Authority: EP
Inventors: Ekkehard Schwab; Stefan Kotrel; Alexander Panchenko; Sigmar BRÄUNINGER; Sandra Magnus; Claudia Querner
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2008-08-26
Filing date: 2009-08-19
Publication date: 2011-06-29
Also published as: JP2012500720A; US20110177938A1; CN102164668B; US8569196B2; KR20110045087A; WO2010026046A1; JP5665743B2; CN102164668A; KR101649384B1

Abstract

The invention relates to a method for continuously producing a catalyst comprising an alloy of a platinum group metal and at least a second metal as an alloying metal selected from the platinum group metals or the transition metals, wherein a catalyst comprising the platinum group metal is admixed with at least one complex compound, each of which contains an alloying metal, to form an alloy precursor, and wherein the alloy precursor is heated in a continuous furnace for producing the alloy.

Description

Process for the continuous production of a catalyst

The invention relates to a process for the continuous production of a catalyst comprising an alloy of a metal of the platinum group and a second metal selected from the metals of the platinum group or the transition metals.

Catalysts containing an alloy of a metal of the platinum group and a second metal are used, for example, in fuel cells. The catalyst is generally applied to an ion-conducting membrane in the form of a catalytically active layer. Usually, such catalyst layers are applied to both sides of the membrane. The membrane provided with the catalyst layers is positioned between two porous gas distribution layers. Through the gas distribution layers, the respective reaction gases are conducted close to the membrane. At the same time, the gas distribution layer also serves to supply and discharge the electrons taken up or released by the reactants. In the catalyst layer, which is located between the membrane and the gas distribution layer, the actual reduction or oxidation reaction takes place. The membrane in turn ensures ionic current transport in the fuel cell. Another object of the membrane is to form a gas-tight barrier between the two electrodes.

The catalysts are suitable, for example, for use as cathode catalysts in fuel cells. Both application in so-called low-temperature fuel cells, for example proton exchange membrane fuel cells (PEMFC), and in high-temperature fuel cells, for example phosphoric acid fuel cells (PAFC), is possible. When used in direct methanol fuel cells (DMFC) cathode catalysts must also have a high tolerance to methanol in addition to a high current density for the oxygen reduction.

Temperature-treated porphyrin-transition metal complexes, e.g. from J. Applied Electrochemistry (1998), pp. 673-682, or transition metal sulfides, for example ReRuS or MoRuS systems, as described e.g. from J. Electrochem. Soc, 145 (10), 1998, pages 3463-3471, see e.g. a high current density for the oxygen reduction and show a good tolerance to methanol. However, these catalysts do not achieve the activity of Pt-based catalysts and are also not stable enough to ensure a sufficient current density in the acidic environment of a fuel cell for a long time.

From US-A 2004/0161641 it is known that Pt catalysts which are alloyed with transition metals have a good methanol tolerance and ensure a sufficiently high current density for the oxygen reduction. For example, it is known from US-A 2004/0161641, that an active methanol-tolerant cathode catalyst should have the highest possible oxygen binding energy with simultaneously low hydrogen bonding energy. High oxygen-binding energy ensures high current density for oxygen reduction, while low hydrogen-binding energy attenuates the electro-oxidative dehydrogenation of methanol to carbon monoxide, thereby increasing methanol tolerance. These properties have according to US-A 2004/0161641 alloys of the elements Fe, Co, Ni, Rh, Pd, Pt, Cu, Ag, Au, Zn and Cd. However, a concrete example of an alloy composition suitable as a methanol-tolerant cathode catalyst is not given.

Alternatively to the use of a methanol-tolerant catalyst, e.g. in Platinum Metals Rev. 2002, 46, (4), the possibility of reducing the methanol throughput by choosing a more suitable membrane. For this, e.g. thicker Nafion membranes are used. At the same time, the lower methanol penetration leads to an increase in the membrane resistance, which ultimately leads to a loss of power of the fuel cell.

The preparation of catalysts containing platinum and ruthenium is eg in AJ. Dickinson et. AI, "Preparation of a Pt-Ru / C Catalyst from carbonyl complexes for fuel cell applications", Elektrochimica Acta 47 (2002), pages 3733-3739. [Ru 3 (CO) i ₂ ] and [Pt ( CO) _2] mixed _x and active carbon with o-xylene. This mixture was heated for 24 hours at 143 ⁰ C under constant mechanical stirring to reflux. Subsequently, the mixture was cooled and the o-xylene removed by distillation. the refluxing was The process described leads to a catalyst rich in ruthenium.

An overview of preparation techniques for the preparation of Pt-Ru catalysts for use in direct methanol fuel cells is provided by H. Liu et. al., "A review of anode catalysis in the direct methanol fuel cell", Journal of Power Sources, 155 (2006) pages 95-110. Suitable methods of preparation include, on the one hand, the impregnation of carbon carriers with metal-containing precursors, the application of colloidal metal alloy particles The application of colloidal metal alloy particles to supports and the synthesis of highly dispersed metal particles in microemulsions require the use of very expensive starting materials, for example surfactants However, the disadvantage of impregnation is that it is generally difficult to control the size of the nanoparticles and their distribution, and in particular the use of high-boiling solvents, as is often the case during impregnation but problematic in the production of technically relevant amounts of catalyst. In another known method, a platinum catalyst is first prepared in a first step. This is again after filtration, washing and drying in a liquid reaction medium, generally water, dispersed. To the dispersion, the element to be incorporated is added in the form of a suitable soluble salt and precipitated with a suitable precipitant, preferably sodium carbonate. The resulting dispersion is filtered, the separated solid washed, dried and then subjected to a high temperature treatment under a reducing atmosphere. The disadvantage of this process, however, is that a product which has already been filtered, washed and dried must be subjected a second time to this sequence of processing steps.

It is therefore an object of the present invention to provide a process for the preparation of a catalyst which does not have the disadvantages of the processes known from the prior art. In particular, it is the object of the present invention to provide a process by means of which a catalyst having a reproducible size of nanoparticles and distribution can be produced continuously.

The object is achieved by a method for producing a catalyst comprising an alloy of a metal of the platinum group and at least one second metal as alloying metal, selected from the metals of the platinum group or the transition metals, comprising the following steps:

(a) blending a catalyst containing the metal of the platinum group with at least one thermally decomposable compound, each containing an alloying metal, to form an alloy precursor,

(b) heating the alloy precursor in a continuously operated furnace to produce the alloy.

The catalyst prepared according to the invention is stable to acids and has a high current density for the oxygen reduction, as desired by cathode catalysts in fuel cells.

The catalyst containing the metal of the platinum group is mixed with the at least one complex compound containing the alloy metal in step (a), preferably to a dry or wet powder. This avoids having to refilter, wash and dry the already washed and dried catalyst containing the metal of the platinum group. All that follows is heating in step (b) to obtain the alloy. - A -

As a continuously operated furnace used to form the alloy, a rotary kiln or a belt calciner is preferably used. In particular, when using a rotary kiln, the amount of gaseous compounds which is formed in the preparation of the alloy by decomposition of the complex compound, remove, so that the production of larger amounts of catalyst is possible.

The catalyst containing the platinum group metal is present, for example, as a metallic powder.

In order to achieve a sufficiently good catalytic activity, it is necessary that the catalyst has a large specific surface area. This is preferably achieved in that the catalyst contains a carrier, wherein the alloy of the metal of the platinum group and the second metal is applied to the carrier. To achieve a large surface area, it is preferred if the support is porous.

When the catalyst is supported on the carrier, individual particles of the catalyst material are generally contained on the carrier surface. Usually, the catalyst is not present as a continuous layer on the support surface.

For preparing the catalyst containing the carrier, it is preferable that the catalyst containing the metal of the platinum group already includes the carrier.

The carrier used here is generally a catalytically non-active material, to which the catalytically active material is applied, or which contains the catalytically active material. Suitable, non-catalytically active materials which can be used as carriers are, for example, carbon or ceramics. Other suitable support materials are, for example, tin oxide, preferably semiconducting tin oxide, γ-alumina, which is optionally carbon-coated, titanium dioxide, zirconium dioxide or silicon dioxide, the latter preferably being highly dispersed, the primary particles having a diameter of 50 to 200 nm. Also suitable are tungsten oxide and molybdenum oxide, which are also known as bronzes, d. H. may be present as substoichiometric oxide. Also suitable are carbides and nitrides of metals of IV. To VII. Subgroup of the Periodic Table of the Elements, preferably of tungsten and molybdenum.

However, particularly preferred as a carrier material is carbon. An advantage of carbon as a carrier material is that it is electrically conductive. When the catalyst is used as an electrocatalyst in a fuel cell, for example as the cathode of the fuel cell, it is necessary for it to be electrically conductive in order to ensure the function of the fuel cell. The carbon used as a carrier may be, for example, as Activated carbon, carbon black, graphite or nanostructured carbon. Suitable carbon blacks are, for example, Vulcan XC72 or Ketjen black EC300. When the carbon is nanostructured carbon, carbon nanotubes are preferred. To prepare the catalyst, the metal of the platinum group is combined with the carrier material.

When the catalyst containing the metal of the platinum group further comprises a support, usually the metal of the platinum group is first deposited on the support. This is generally done in solution. For this, e.g. Metal compounds be dissolved in a solvent. The metal can be bound covalently, ionically or complexed. Furthermore, it is also possible that the metal is deposited reductively, as a precursor or alkaline by precipitation of the corresponding hydroxide. Further possibilities for the deposition of the metal of the platinum group are also impregnations with a metal-containing solution (Incipient Wetness), Chemical Vapor Deposition (CVD) or Physical Vapor Deposition (PVD) processes as well as all other processes known to the person skilled in the art where a metal can be deposited. Preferably, a salt of the metal of the platinum group is first precipitated. After precipitation, drying and temperature treatment are carried out to prepare the catalyst containing the metal of the platinum group.

The preparation of such supported or unsupported catalysts containing a metal of the platinum group is known and corresponding catalysts can be obtained commercially.

According to the invention, the metal of the platinum group is rhodium, iridium, nickel, palladium, platinum, copper, silver and gold. In a preferred embodiment of the invention, however, the platinum group metal is platinum or palladium, most preferably platinum.

If the catalyst used in step (a) containing the metal of the platinum group is unsupported, the metal of the platinum group is preferably present as a powder having a particle size in the range of 1 to 200 microns. In this case, the metal of the platinum group has primary particle sizes in the range of 2 to 20 nm. However, the powder of the metal of the platinum group can also contain further, catalytically inactive constituents. These serve, for example, as release agents. For example, all materials which can also be used as catalyst supports are suitable for this purpose.

The at least one alloying metal contained in the thermally decomposable compound, preferably a complex compound, especially an organometallic complex compound, and is selected from the metals of the platinum group or the Transition metals, is preferably selected from the group consisting of ruthenium, cobalt, nickel and palladium.

Preferably, the at least one alloying metal is present as an organometallic complex compound. Preferred ligands for forming the organometallic complex compound are olefins, preferably dimethyloctadiene, aromatics, preferably pyridine, 2,4-pentanedione. Furthermore, it is also preferred that the at least one alloying metal is in the form of a mixed cyclopentadienyl-carbonyl complex or as a pure or mixed carbonyl, phosphine, cyano or isocyano complex.

It is particularly preferred if the at least one alloying metal is present as organometallic complex compound with acetylacetonate or 2,4-pentanedione as ligand. The at least one alloying metal is preferably ionic.

In order to mix the at least one alloy metal selected from the metals of the platinum group or the transition metals with the catalyst containing the metal of the platinum group, it is preferable that the thermally decomposable compound containing the at least one alloy metal dry. Alternatively, however, it is also possible that the thermally decomposable compound is dissolved in a solvent. The solvent here is preferably selected from the group consisting of ethanol, hexane, cyclohexane, toluene and ether compounds. Preferred ether compounds are open-chain ethers, for example diethyl ether, di-n-propyl ether or 2-methoxypropane, and also cyclic ethers, such as tetrahydrofuran or 1,4-dioxane.

When the thermally decomposable compound containing the at least one alloying metal is dissolved in a solvent, the mixture of the catalyst containing the metal of the platinum group and the at least one organometallic compound or the at least one metal complex before annealing in step (b) dried. The drying can take place at ambient temperature or at an elevated temperature. When drying takes place at elevated temperature, the temperature is preferably above the boiling point of the solvent. The drying time is chosen such that, after drying, the proportion of solvents in the mixture of the catalyst containing the metal of the platinum group and the at least one complex compound is less than 5% by weight, preferably less than 2% by weight. % is.

The mixing of the catalyst containing the metal of the platinum group and the at least one complex compound containing the alloying metal is carried out by any method of mixing solids known to those skilled in the art. Suitable solids mixers usually comprise a container in which the material to be mixed is moved. Suitable solids mixers are, for example, blade mixers, screw mixers, silo mixers or pneumatic mixers.

When the thermally decomposable compound is dissolved in a solvent, it is preferable that the mixture of the catalyst containing the metal of the platinum group and the at least one dissolved complex compound is prepared by a conventional dispersing method known to those skilled in the art. For this purpose, e.g. a container used in the fast rotating blades or blades are included. Such a device is e.g. an Ultra-Turrax®.

However, it is particularly preferred if the catalyst containing the metal of the platinum group is still free-flowing. This is generally the case when the catalyst has a residual moisture of up to 50% by weight of water. When the catalyst is not to be completely dried, the residual moisture content of the catalyst containing the metal of the platinum group is preferably in the range of 20 to 30% by weight of water. Due to the low water content, the mixture of the catalyst containing the metal of the platinum group and the at least one complex compound containing the alloying metal remains free-flowing. This is an essential prerequisite for its operation, in particular when using a rotary kiln as a continuously operated furnace. The residual moisture of the catalyst containing the metal of the platinum group is obtained, for example, by air drying in the production. However, it is of course also possible to use a completely dried catalyst.

To produce an alloy of the metal of the platinum group and the at least one alloying metal selected from the metals of the platinum group or the transition metals, this is by mixing the catalyst containing the metal of the platinum group with the at least one thermally decomposable compound containing the alloying metal heats powders prepared in step (a). For this purpose, the mixture produced in step (a) in a continuously operated oven to a temperature in the range of 90 to 900 ⁰ C, preferably in the range of 350 to 900 ⁰ C, more preferably in the range of 400 to 850 ⁰ C and in particular in the range of 400 to 650 ⁰ C. Upon heating, the at least one complex compound is decomposed and the metal bound in it is liberated. The metal combines with the metal of the platinum group. The result is an alloy in which each metal crystallites are juxtaposed. The individual metal crystallites generally have a size in the range of 2 to 7 nm.

In a preferred embodiment, the heating takes place in two temperature stages, wherein the temperature of the first temperature stage is lower than the temperature of the second temperature stage. It is also possible that the heating takes place in more than two temperature stages. fen. In each case, the temperature of the subsequent temperature stage is preferably higher than the temperature of the preceding temperature stage. However, it is preferred that the heating takes place in two temperature stages.

If the heating of the alloy precursor in step (b) is carried out in two temperature stages, it is preferred that the temperature of the first temperature stage in the range of 300 to 500 ⁰ C., preferably in the range 350-480 ⁰ C and in particular in the range of 370 to 460 ⁰ C, and the temperature of the second temperature stage in the range of 500 to 700 ⁰ C, more preferably in the range of 550 to 680 ⁰ C and in particular in the range of 570 to 660 ⁰ C. The temperature of the second temperature stage is preferably at least 100 ⁰ C, preferably at least 150 ⁰ C, higher than the temperature of the first tem- peraturstufe.

The residence time in the continuously operated furnace in step (b) is preferably in the range of 30 minutes to 10 hours, more preferably in the range of 45 minutes to 5 hours and in particular in the range of 1 to 2 hours.

The heating of the alloy precursor in step (b) is preferably carried out under a reducing atmosphere. The reducing atmosphere preferably contains hydrogen. The proportion of hydrogen is dependent on the composition of the catalyst to be prepared. The proportion of hydrogen in the reducing atmosphere can be up to 100% by volume. Preferably, a Formiergasatmosphäre is used, wherein the concentration of hydrogen is usually less than 30 vol .-%, generally less than 20 vol .-%. Particularly preferably, the proportion of hydrogen in the reducing atmosphere is less than 10% by volume and in particular about 5% by volume. In particular, in the production of a Pt-Ni catalyst or a Pt-Co catalyst, the proportion of hydrogen in the reducing atmosphere, preferably in the range of 4 to 10 vol .-%, in particular about 5 vol .-%.

In addition to hydrogen, the reducing atmosphere preferably contains at least one inert gas. Preferably, the reducing atmosphere contains nitrogen. Alternatively, however, it is also possible that argon is used instead of the nitrogen, for example. It is also possible to use a mixture of nitrogen and argon. However, nitrogen is preferred.

In particular, it is preferred if the reducing atmosphere contains no further constituents in addition to the hydrogen and the inert gas. However, it should not be ruled out that, for example due to gas production, traces of other gases are still present. After heating to form the alloy in step (b), passivation is preferably carried out. For this purpose, the produced alloy is cooled, for example, to ambient temperature under an inert atmosphere. The inert atmosphere is preferably a nitrogen atmosphere or an argon atmosphere. It is also possible to use a mixture of nitrogen and argon. Also, the alloy produced in step (b) may be introduced, for example, into a water blanket after leaving the continuously operated furnace for passivation.

The catalyst prepared by the process according to the invention is suitable, for example, for use as electrode material in a fuel cell. Typical fuel cells in which the catalyst can be used are, for example, proton exchange membrane fuel cells (PEMFC), direct methanol fuel cells (DMFC), direct ethanol fuel cells (DEFC), and phosphoric acid fuel cells (PAFC). In particular, the catalyst prepared by the process according to the invention is suitable as a cathode catalyst, i. as a catalyst for oxygen reduction. Other suitable applications are the electro-oxidation of methanol or hydrogen outside of fuel cells, the electroreduction of oxygen, chlor-alkali electrolysis and water electrolysis. Also, the catalyst prepared by the process of the present invention can be e.g. in automotive exhaust gas catalysis, for example as a 3-way catalyst or diesel oxidation catalyst, or for catalytic hydrogenation or dehydrogenation in the chemical industry. These include e.g. Hydrogenations of unsaturated aliphatic, aromatic and heterocyclic compounds. Dehydrogenation of carbonyl, nitrile, nitro groups and of carboxylic acids and their esters, aminating hydrogenations, hydrogenations of mineral oils and carbon monoxide. Dehydrogenation of paraffins, of naphthenes, of alkylaromatics and of alcohols is mentioned as an example of dehydrogenation. The hydrogenation or dehydrogenation can be carried out both in the gas phase and in the liquid phase.

Examples

Comparative Example 1

For preparing a carbon-supported platinum catalyst 100 g of a commercially available carbon black are first carrier (CABOT XC72) using an Ultra-Turrax ^® - dispersing dispersed into 4 liters of water. 57.14 g of Pt (NO ₃ ) ₂ dissolved in 250 ml of H ₂ O are added to the suspension. Thereafter, 4250 ml of ethanol are added to the mixture and heated to boiling. The suspension is boiled for 5 h at reflux, cooled to 60 ⁰ C, filtered through a Buchner funnel with paper filter and washed with 10 l cold H ₂ O NO ₃ -free. The carbon-supported platinum catalyst thus prepared is then reslurried as a wet washed filter cake in 3 IH ₂ O. With about 20 drops of 65% HNO ₃ , the pH of the suspension is adjusted to 2.1. To the suspension is 48.86 g Ni (NO ₃₎ ^■ 6H ₂ O dissolved in 400 ml H ₂ O was added. The mixture is then thoroughly mixed for 10 minutes, and the pH is increased to 8.5 with about 290 ml of 10% strength Na ₂ CO ₃ solution. The suspension is stirred for 1 h at 75 ⁰ C and the pH of 8.5. Subsequently, a 6.3% formaldehyde solution, which is prepared by dilution of 18 ml of 35% formaldehyde solution to 100 ml, was added and stirred at 75 ⁰ C again for 1 h.

After the reaction, the suspension is cooled to about 60 ⁰ C and the catalyst filtered off by suction through a Buchner funnel with paper filter and washed with 15 liters of cold H ₂ O NO ₃ -free. In a rotary kiln, the catalyst is then dried for about 48 h at 80 ⁰ C oven temperature under a nitrogen atmosphere.

To form the PtNi alloy, the product obtained is heated in a hydrogen / argon atmosphere with 15 vol .-% hydrogen at a rate of 5 ° C / min to 500 ⁰ C, held for 30 min at this temperature and then also with a Rate of 5 ° C / min heated to 850 ⁰ C, held again for 30 min at this temperature, then cooled to room temperature and in nitrogen, dam stepwise air is added until air atmosphere is present, passivated.

The platinum content of the catalyst thus prepared is 23.2 wt .-%, the nickel content at 6.8 wt .-% and the water content at less than 0.5 wt .-%. The PtNi crystallite size is 9.0 nm and the lattice constant is 3.810 Å.

Comparative Example 2

For preparing a supported platinum catalyst 75.8 g of a commercially receives at union carbon black carrier are (CABOT XC72) using an Ultra-Turrax ^® -Dispergiergerätes dispersed in 3 I water. To the solution is added 1 liter of a 4% platinum nitrate solution. Then 4.25 l of ethanol are added and the mixture is heated to reflux for 5 h under reflux. The resulting catalyst dispersion is filtered off via a groove and allowed to dry the filter cake obtained in the air until it has a residual moisture content of 22 wt .-%. Finally, the dried filter cake is comminuted over a 0.4 mm sieve.

1 1, 5 g of the carbon-supported platinum catalyst thus prepared are 4.47 g

Nickel acetylacetonate blended and filled in a batch operated rotary kiln. First, the mixture for 2 h at 100 ⁰ C while passing nitrogen dried. Connecting is converted to a stream of 0.8 l / h of hydrogen and 15 l / h of nitrogen and gradually heated up to 600 ⁰ C. Subsequently, the catalyst thus prepared is cooled and passivated at room temperature with air / nitrogen.

The prepared catalyst has a platinum content of 21, 6 wt .-%, a nickel content of 8.7 wt .-% and a water content of 0.5 wt .-%. The crystallite size of the PtNi crystallites is 2.4 nm and the lattice constant of the PtNi alloy is 3.742 Å.

example

A carbon supported platinum catalyst is prepared as described in Comparative Example 2.

28.8 g of the carbon-supported platinum catalyst thus prepared are mixed with 1 1, 2 g of nickel acetylacetonate and filled into the reservoir of a continuously operable rotary kiln. The rotary kiln has three heating zones, the first heating zone at 400 ⁰ C and the second and third heating zones are adjusted respectively to 600 ⁰ C. The gas atmosphere in the rotary kiln consists of a mixture of 5 vol .-% hydrogen in 95 vol .-% nitrogen. The capacity of the rotary kiln is adjusted so that per hour 50 g of catalyst are conveyed through the rotary kiln. The residence time of the product in the heated zone of the rotary kiln is 1 h.

The product obtained is collected after leaving the rotary kiln in a receiver and finally passivated out of the rotary kiln in an air / nitrogen stream.

The catalyst thus prepared has a platinum content of 17.8% by weight, a nickel content of 7.9% by weight and a water content of 0.6% by weight. The crystallite size of the PtNi crystallites is 2.4 nm and the lattice constant of the PtNi alloy is 3.762 Å.

Claims

claims

A process for the continuous production of a catalyst comprising an alloy of a metal of the platinum group and at least one second metal as alloying metal selected from the metals of the platinum group or of the transition metals, comprising the following steps:

2. The method according to claim 1, characterized in that the continuously operated furnace is a rotary kiln or a belt calciner.

3. The method according to claim 1 or 2, characterized in that the heating in step (b) takes place under a reducing atmosphere.

4. The method according to claim 3, characterized in that the reducing atmosphere contains hydrogen.

5. The method according to claim 3 or 4, characterized in that the proportion of hydrogen in the reducing atmosphere is less than 30 vol .-%.

6. The method according to any one of claims 1 to 5, characterized in that the temperature to which the alloy precursor is heated in step (b) in the range of 90 to 900 ⁰ C.

7. The method according to any one of claims 1 to 6, characterized in that the heating takes place in two temperature stages, wherein the temperature of the first temperature level is lower than the temperature of the second temperature level.

8. The method according to claim 7, characterized in that the temperature of the first temperature stage in the range of 300 to 500 ⁰ C and the temperature of the second temperature level in the range of 500 to 700 ⁰ C, wherein the temperature of the second temperature stage at least 100 ⁰ C. is higher than the temperature of the first temperature stage.

9. The method according to any one of claims 1 to 8, characterized in that the residence time in the continuously operated oven is in the range of 30 minutes to 10 hours.

10. The method according to any one of claims 1 to 9, characterized in that the catalyst containing the metal of the platinum group is present as a metallic powder or further comprises a carrier.

1 1. A method according to claim 10, characterized in that the carrier is a carbon carrier.

12. The method according to any one of claims 1 to 11, characterized in that the catalyst containing the metal of the platinum group, a residual moisture content of up to 50 wt .-% water.

13. The method according to any one of claims 1 to 12, characterized in that the metal of the platinum group is platinum.

14. The method according to any one of claims 1 to 13, characterized in that the alloying metal is selected from the group consisting of ruthenium, cobalt, nickel and palladium.

15. The method according to any one of claims 1 to 14, characterized in that the at least one thermally decomposable compound is an organometallic compound or a metal complex.

16. The method according to any one of claims 1 to 15, characterized in that the at least one alloy metal or metal complex with an olefin, preferably dimethyloctadiene, an aromatic, preferably pyridine, 2,4-pentanedione as ligands, as a mixed cyclopentadienyl-carbonyl complex or is present as a pure or mixed carbonyl, phosphine, cyano or Isocyano complex.

17. The method according to any one of claims 1 to 16, characterized in that the at least one alloying metal is present as a metal complex with acetylacetonate or 2,4-pentanedione as a ligand.

18. The method according to any one of claims 15 to 17, characterized in that the at least one organometallic compound or the at least one metal complex containing the at least one alloying metal, as a powder or dissolved in a solvent.

19. The method according to any one of claims 1 to 18, characterized in that after heating to form the alloy in step (b) passivation is performed.