Enhanced activity of carbon-supported PdCo electrocatalysts toward electrooxidation of ethanol in alkaline electrolytes

Abstract

Carbon-supported Pd and PdCo (1: 2, 1: 1, 2: 1 and 3: 1) catalysts were synthesized by chemical reduction with NaBH4. Their electrochemical properties were investigated by cyclic voltammetry, chronoamperometry and CO stripping voltammetry in alkaline electrolytes, and compared with commercial Pt/C and PtRu(1: 1)/C catalysts. In electrochemical oxidation of ethanol in an alkaline electrolyte, marked improvements in the current density and onset potential were observed by incorporating Co into Pd/C to form PdCo/C alloy electrocatalysts. The best catalyst PdCo (1: 1)/C showed performance superior to the commercial Pt/C or PtRu/C catalysts. It is shown that the incorporated Co facilitates the oxidation of strongly-adsorbed carbonaceous intermediate species on the surface of Pd by forming OH- group and reacts away the intermediates from Pd surface. Thus, PdCo(1: 1)/C catalyst is a promising anode catalyst for direct ethanol fuel cells with alkaline electrolytes.