Reduced poisoning of platinum fuel-cell electrocatalysts supported on desulfurized carbon

The vulcanized carbon (VC) used to support nanoscale Pt catalysts in H-2/O-2 fuel cells contains organosulfur that poisons the Pt upon heating in the absence of water. We have previously shown that in the art of making fuel-cell electrodes (which includes water and heat), surface-sited organosulfur in the VC is catalytically oxidized to innocuous sulfate when it contacts PtOx. When the carbon surface is desulfurized, electroactive electrodes can be fabricated without water and at temperatures that would otherwise poison Pt when mixed with standard VC. The subsurface organosulfur in VC does not migrate over time to the desulfurized carbon surface under ambient conditions to deactivate supported Pt. Electroactive Pt/low sulfur-content carbon electrodes can now be made using nonaqueous protocols. Low-sulfur-content carbon supports should reduce performance losses in fuel cells. (C) 1999 The Electrochemical Society. S1099-0062(99)08-056-6. All rights reserved.