NOVEL ELECTROCATALYSIS IN POLYMER ELECTROLYTE FUEL CELLS

THIS PHASE I INVESTIGATION ADDRESSES IMPROVING PERFORMANCE AND LOWERING COSTS ASSOCIATED WITH POLYMER ELECTROLYTE (PE) FUEL CELL ELECTROCATALYSIS. THE APPROACH IS TO SUBSTITUTE BINUCLEAR TRANSITION METAL CHALCOGENIDE CLUSTER COMPOUNDS FOR DISPERSED PLATINUM CURRENTLY USED AS ACTIVE SITES FOR PROMOTING ELECTROCHEMICAL HYDROGEN OXIDATION AND OXYGEN REDUCTION. HIGH ELECTROCATALYTIC ACTIVITY IS AN ANTICIPATEDCONSEQUENCE OF THE ABILITY OF THESE OCTAHEDRAL MIXED-METAL CLUSTERS TO STABILIZE A HIGH POPULATION OF DELOCALIZED D-ELECTRONS BETWEEN THE METAL-METAL CENTER. THIS STABILIZATION PROVIDES AN ELECTRON RESERVOIR COMPATIBLE WITHPROMOTING EITHER SINGLE OR MULTI-ELECTRON TRANSFER REACTIONSAT LOW APPLIED OVERPOTENTIALS. ELECTROCATALYTIC ACTIVITY ISSYSTEMATICALLY ADJUSTED BY MODIFYING THE METAL CLUSTER STOICHIOMETRY, THEREBY INCREASING OR DECREASING INTERMETALLIC DISTANCES CAUSED BY RESPECTIVE ANTIBONDING OR BONDING ELECTRON POPULATIONS. INCORPORATION OF THESE CHALCOGENIDE CLUSTER ELECTROCATALYTIC SITES, WHETHER AS FINELY DISPERSED PARTICLES OR AS INITIAL DEPOSITS ONTO A CARBON SUPPORT WITHIN GAS DIFFUSION TYPE ELECTRODES, IS EXPECTED TO LEAD TO IMPROVED ELECTROCHEMICAL PERFORMANCE. THIS IMPROVED PERFORMANCE IS ACHIEVED AT THE DIFFUSION ELECTRODE/PE INTERFACE INCORPORATED WITHIN HYDROGEN/OXYGEN POLYMER ELECTROLYTE FUEL CELLS.