Electrocatalysis of Pd-Co supported on carbon black or ball-milled carbon nanotubes towards methanol oxidation in alkaline media

Pd/C and Pd-Co/C catalysts were synthesized through a simple simultaneous reduction reaction with sodium borohydride in aqueous solution, and the electrocatalytic performance for methanol oxidation in alkaline solutions was investigated. The structure and morphology of these catalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The cyclic voltammetry (CV) and CO stripping results show that Pd-Co(8:1)/C has better electrocatalytic activity and higher resistance to CO poisoning over Pd/C, which can be explained by a bifunctional mechanism. Based on the good electrocatalytic performance of Pd-Co(8:1)/C, the ball-milled CNTs-supported Pd-Co(8:1) catalyst was synthesized, demonstrating even better catalytic activity. The high specific surface area of ball-milled CNTs with plenty of mesopores and defects may contribute to the high Pd-Co utilization and consequently to the better electrocatalytic activity. (C) 2010 Elsevier B.V. All rights reserved.