A Comparative Study of Variously Prepared Carbon-Supported Pt/MoO[sub x] Anode Catalysts for a Polymer Electrolyte Fuel Cell

Carbon-supported anode catalysts were prepared by the preimpregnation, postimpregnation, and chemical reduction methods. The physicochemical characteristics of all catalysts were determined by X-ray diffraction, scanning transmission electron microscopy, and CO pulse titration. The electrochemical oxidation of CO verified from CO-stripping voltammetry shows that most of the were oxidized on the Pt sites. The catalyst prepared by the chemical reduction method showed superior hydrogen electrochemical oxidation in pure , apparently due to the much smaller Pt particle size than those of the other catalysts. However, the anode performances in the presence of 500 ppm mixture showed that a catalyst with high CO tolerance was derived from the catalyst prepared by postimpregnation method. The oxidation of CO by the water–gas shift (WGS) reaction is shown by the formation of even under an open-circuit condition. With an increase in current, active sites for the WGS reaction is regenerated by electrochemical oxidation of hydrogen.