Enhanced activity of methanol electro-oxidation on Pt–V 2O 5/C catalysts

Abstract

The Vulcan carbon-supported vanadium oxide (V 2O 5) 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 V 2O 5/C. The catalyst samples were characterized by PXRD, TEM, CO-TPD and electrochemical methods. The TEM images showed homogeneous dispersion of ∼3 nm size Pt metal crystallites embedded over Vulcan carbon support. The activities of Pt/C and Pt–V 2O 5/C for electrochemical oxidation of methanol were studied in 1.0 M KOH solution by cyclic voltammetry, chronoamperometry and chronopotentiometry. The influence of V 2O 5 component on the activity of Pt–V 2O 5/C was screened for catalytic oxidation of methanol. The results show that Pt–V 2O 5(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–V 2O 5/C electrocatalyst. The formation of oxygen-containing species at lower potential can transform CO-like poisoning species on Pt to CO 2 in the presence of V 2O 5 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 V 2O 5.