Enhanced activity of methanol electro-oxidation on Pt-V2O5/C catalysts

The Vulcan carbon-supported vanadium oxide (V2O5) was prepared by solid-state reaction under intermittent microwave heating (IMH) method. Pt nanoparticles were dispersed by microwave-assisted polyol process over Vulcan carbon and V2O5/C. The catalyst samples were characterized by PXRD, TEM, CO-TPD and electrochemical methods. The TEM images showed homogeneous dispersion of similar to 3 nm size Pt metal crystallites embedded over Vulcan carbon support. The activities of Pt/C and Pt-V2O5/C for electrochemical oxidation of methanol were studied in 1.0 M KOH solution by cyclic voltammetry, chronoamperometry and chronopotentiometry. The influence Of V2O5 component on the activity Of Pt-V2O5/C was screened for catalytic oxidation of methanol. The results show that Pt-V2O5(4:3)/C composite catalyst performed better than Pt/C catalyst for methanol oxidation. The temperature programmed desorption (TPD) with CO was carried out to assess the CO tolerance of Pt-V2O5/C electrocatalyst. The formation of oxygen-containing species at lower potential can transform CO-like poisoning species on Pt to CO2 in the presence Of V2O5 which helps in regenerating active sites on Pt for further electrochemical oxidation of methanol. The enhanced electrode response is attributed to synergistic effect between Pt and V2O5. (c) 2008 Elsevier B.V. All rights reserved.