Insights on the SO2 Poisoning of Pt3Co/VC and Pt/VC Fuel Cell Catalysts
NAVAL RESEARCH LAB WASHINGTON DC
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SO2 poisoning of carbon-supported Pt3Co Pt3CoVC catalyst is performed at the cathode of proton exchange membrane fuel cellsPEMFCsin order to link previously reported results at the elec- trodesolution interface to the FC environment. First, the surface area of Pt3CoVC catalyst is rigorously characterized by hydrogen adsorption,CO stripping voltammetry and under potential depositionupd of copper adatoms.Then the performance of PEMFC cathodes employing 30wt.Pt3CoVC and 50wt.PtVC catalysts is compared after exposure to 1ppmSO2 in air for 3 h at constant cell voltage of 0.6V.In agreement with results reported for the electrodesolution interface,thePt3CoVC is more susceptive to SO2 poisoning than PtVC at a given platinum loading. Both catalysts can be recovered from adsorbed sulfur species by running successive polarization curves in air or cyclic voltammetry CVin inert atmosphere.However,the activity of Pt3CoVC having 87643 times higher sulfur coverage is recovered more easily than PtVC.To understand the difference between the two catalysts in terms of activity recovery,platinumsulfur interaction is probed by thermal programmed desorption at the catalystinert gas interface and CV at the electrodesolution interface and in the FC environment.
- Inorganic Chemistry
- Electrical and Electronic Equipment
- Electrochemical Energy Storage