Tungsten carbide on directly grown multiwalled carbon nanotube as a co-catalyst for methanol oxidation

Abstract

Multiwalled carbon nanotubes (MWCNT) were grown directly on the surface of graphite rod by using CVD process and then modified with tungsten carbide by carbothermal hydrogen carbonization technique. Then, platinum nanoparticles were deposited on the MWCNTs by means of electrodeposition technique. Catalyst materials were characterized by electron microscopy, X-ray photoelectron spectroscopy and three electrode electrochemical measurements. Catalysts supported on the directly grown MWCNTs exhibit notably better electrocatalytic performance towards methanol oxidation compared to the commercial Pt/C catalyst. Modification of MWCNTs with tungsten carbide was shown to further increase the catalyst performance. It is believed that the superior performance of catalysts prepared on the MWCNTs as catalyst support results mostly from the superior electrical contact and unique spatial configuration of the directly grown MWCNTs, while the positive effect of the tungsten carbide co-catalyst is mostly attributed to its improved resistance towards poisoning with the reaction intermediates produced during the methanol oxidation. © 2012 Elsevier B.V.