Vanadium oxide decorated carbon nanotubes as a promising support of Pt nanoparticles for methanol electro-oxidation reaction

VOx-MWCNTs nanocomposite was prepared via deposition-precipitation method followed by microwave treatment. Platinum nanoparticles were dispersed via polyol process over the nanocomposite support, and thus, prepared electro-catalyst was employed in methanol electro-oxidation reaction. The electro-catalysts were characterized by means of TGA, XRD, EDS, FESEM, TEM, and H-2-TPR analysis. The electro-catalytic activity and stability of the electrodes toward methanol oxidation reaction in acidic medium were studied by using cyclic voltammetry (CV), CO-stripping, and electrochemical impedance spectroscopy (EIS) techniques. Compared to the Pt/MWCNTs, the Pt/VOx-MWCNTs electro-catalyst not only exhibits high electro-catalytic activity, but also shows very good stability during methanol electro-oxidation reaction. In addition, the presence of VOx in the composite support dramatically increases the electrochemical active surface area of platinum nanoparticles. The results of electrochemical impedance spectroscopy reveal that formation kinetics of adsorbed hydroxyl group on surface of the electrocatalysts is improved upon vanadium oxide addition to the support. This phenomenon is very helpful to facilitate oxidative removal of adsorbed CO group through bifunctional mechanism on Pt/VOx-MWCNTs. (C) 2012 Elsevier Inc. All rights reserved.