Oxygen Reduction by Sol-Derived Pt∕Co-Based Alloys for PEM Fuel Cells

Abstract

A route toward the synthesis of several -based catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells is described here. The composition of these catalysts has been determined by X-ray diffraction studies, while their electrochemical activity was established using slow sweep cyclic voltammetry in 0.5 M at room temperature. We have found that by mixing a Co oxide sol precursor with Pt supported on carbon , followed by heat-treatment at 700 or 900°C, the active PtCo alloy catalyst is formed. In contrast, when exactly the same procedure is followed but a Co oxide sol-derived catalytic material is employed, alloy catalysts, which are somewhat less active toward the ORR, are formed. Catalysts formed by heating at 900°C are more active than those formed at 700°C, and all of our catalysts are more active toward the ORR than pure Pt on carbon.