Nanoparticles of platinum and hydrous molybdenum oxide (Pt/HxMoO3) were successfully electrodeposited onto poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) film by chronocoulornetry (0.2 C). Various loadings of Pt/HxMoO3 particles onto the PEDOT-PSS electrode were achieved using the co-deposition technique. The existence of Pt/HxMoO3 particles was determined through characterization by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. XPS results revealed that deposited Pt and molybdenum were metallic Pt and HxMoO3, respectively. XRD analysis showed a decrease of Pt crystalline facets for the incorporation of HxMoO3 into PEDOT-PSS-Pt. indicating a strong interaction between Pt and HxMoO(3). Scanning electron microscopy (SEM) results revealed a uniform dispersion of Pt/HxMoO3 particles, with the particle size of 70-90 nm, in the PEDOT-PSS matrix. The cyclic voltammetry study and chronopotentiometry measurements demonstrated that the PEDOT-PSS-Pt/HxMoO3 electrode had superior electrocatalytic activity of methanol oxidation with less CO poisoning. The presence of amorphous HxMoO3 particles on the Pt Surface minimized CO poisoning of methanol oxidation. (C) 2008 Elsevier B.V. All rights reserved.