The influence of poisoning of MoO(x)-Pt catalyst by CO on the kinetics of H(2) oxidation reaction (HOR) at MoO(x)-Pt electrode in 0 5 mol dm(-3) HClO(4) saturated with H(2) containing 100 ppm CO was examined on rotating disc electrode (RIDE) at 25 C MoO(x)-Pt nano catalyst prepared by the polyole method combined with MoO(x) post deposition was supported on commercial carbon black Vulcan XC 72 The MoO(x)-Pt/C catalyst was characterized by TEM technique The catalyst composition is very similar to the nominal one and post deposited MoO(x) species block only a small fraction of the active Pt particle surface area MoO(x) deposition on the carbon support can be ruled out from the EDAX results and from the low mobility of these oxides under used conditions Based on Tafel-Heyrovsky-Volmer mechanism the corresponding kinetic equations from a dual pathway model were derived to describe oxidation current potential behavior on RIDE over entire potential range at venous CO coverages The polarization RIDE curves were fitted with derived polarization equations according to the proposed model The fitting showed that the HOR proceeded most likely via the Tafel-Volmer (TV) pathway A very high electrocatalytic activity observed at MoO(x)-Pt catalyst for the hydrogen oxidation reaction in the presence of 100 ppm CO is achieved through chemical surface reaction of adsorbed CO with Mo surface oxides (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved