Studies Of Fuel Cell Anode Electrocatalysis

Abstract

Several aspects of anode catalysis for proton exchange membrane fuel cells are addressed in this work, including mechanistic studies of alternative fuels, development of instrumentation for analysis of new materials, and fuel cell testing of novel materials. The electrooxidation of dimethoxymethane (DMM) at platinum was studied using differential electrochemical mass spectrometry (DEMS) and in situ FTIR spectroscopy. The effects of specific anion adsorption, concentration, and potential upon the product distribution were investigated. Methyl formate and CO2 were detected as products, and the former was found to be more prevalent under all conditions tested. DEMS and FTIR measurements on 13C - labeled DMM revealed that the CO2 originated preferentially from the methyl carbons. The electrooxidation of two structurally related acetals, 1,1 - dimethoxyethane and 2,2 - dimethoxypropane was also investigated. The development of a combined scanning DEMS - scanning electrochemical microscope (SECM) instrument is presented. This instrument will be used as a supplement to ongoing screening of combinatorial libraries of fuel cell anode catalysts, by providing spatial resolution of product formation across the composition spread. Fuel cell testing results for a Pt/Ti0.7W0.3O2 catalyst, of interest for CO tolerance, are described. Preliminary results for the fuel cell testing of alkaline anion exchange membrane fuel cells are also presented.