Platinum alloy catalyst for fuel cells and method of its production
AssigneeDegussa AG
InventorsReinhold Brand, Andreas Freund, Jutta Lang, Thomas Lehmann, Johannes Ohmer, Thomas Tacke, Gerhard Heinz, Robert Schwarz
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Abstract
A ternary platinum alloy catalyst on a conductive carbon carrier for use in fuel cells is disclosed. For the production of the catalyst, nitrate salts are used as precursors of the alloy components and all alloy components are deposited concurrently on the carbon carrier. This method of procedure yields ageing-stable catalysts with high oxygen mass activity.
Claims23
A platinum alloy catalyst on a conductive carbon carrier containing as catalytically active component a ternary alloy consisting of the alloy components platinum, cobalt and chromium, prepared by a process comprising forming an aqueous suspension of carbon carrier, heating said suspension to 80.degree. to 90.degree. C., mixing said suspension with an aqueous solution of precursors of said alloy components, maintaining said suspension at a constant temperature of 70.degree. to 80.degree. C., precipitation said alloy components in the form of their hydroxides by adding a base to said suspension, reducing said alloy components with a reducing agent, washing and drying the catalytic precursor thereby obtained and calcining said catalytic precursor at temperatures above 800.degree. C., wherein the precursors of the alloy components are nitrates which are precipitated in common onto said carbon carrier to thereby obtain said platinum alloy catalyst on said conductive carbon carrier.
A method of producing a platinum alloy catalyst on a conductive carbon carrier containing as catalytically active component a ternary alloy consisting of the alloy components platinum, cobalt and chromium comprising:
- preparing an aqueous suspension of the carbon carrier by mixing water with a conductive carbon, heating said suspension to 80.degree. C. to 90.degree. C., mixing said suspension with an aqueous solution of precursors of the alloy components, thereafter maintaining said suspension at a constant temperature between 70.degree. C. to 80.degree. C., simultaneously precipitating the alloy components in the form of their hydroxides onto said carbon by adding a base, adding a reducing agent to reduce the alloy components to the corresponding metal, washing and drying the catalytic precursor so obtained and calcining at temperatures above 800.degree. C. for alloy formation, wherein the precursors of the alloy components are nitrates which are precipitated in common onto the carbon carrier, the pH of the suspension being raised by the addition of sodium hydroxide solution as said base to a valve between 8 and 9 for the complete and simultaneous precipitation of the alloy components.
Dependencies are inferred from the claim text.