Economical solid polymer electrolyte fuel cells (SPEFCs) have potential commercial applications for example as auxiliary power fuel cell systems for cruise ships, offshore platforms, and remote navigation systems. Compared to other currently used electricity generating systems, fuel cells offer many advantages, including (1) high fuel to electricity conversion efficiency at both rated and part load; (2) molecular construction; and (3) low pollutant levels. A major impediment to the commercialization of SPEFC is the high cost of the unsupported platinum electrocatalyst. In this work the PIs plan to develop high utilization pulse plated carbon supported electrocatalysts for SPEFC applications which reduce the platinum cost by factors of 20 to 40 relative to the state-of-the-art. In order to obtain a high utilization carbon supported SPEFC electrocatalyst, the PIs plan to electrodeposit the platinum catalyst particles onto the carbon support after it has been fabricated into a gas diffusion electrode and impregnated with Nafion. In this approach a porous gas diffusion electrode structure will be prepared with high surface area carbon (not Pt catalyzed) and Teflon using conventional techniques. A solution of solubilized Nafion will then be painted or sprayed into the porous carbon electrode structure. The membrane side of the electrode will then be exposed to platinum electroplating solution and small particles of platinum will be deposited. In this manner, the platinum catalyst particles are deposited onto the carbon support only in regions accessible by the solid electrolyte. Consequently, all the platinum particles have ionic accessibility and result in greatly increased platinum utilization. The objective of this Phase I research program is to demonstrate the feasibility of preparing a high utilization carbon supported platinum electrocatalyst using pulse plating. Towards this objective, the following questions will be addressed: o Can small platinum particles (15 to 35 ) be deposited onto a smooth graphitic or glassy carbon surface using pulse plating? o Can the pulse plating deposition technique be extended to solid polymer electrolyte coated carbon surfaces?
