Electrocatalytic oxidation of methanol on a platinum modified carbon nanotube electrode

A thin film of poly(o-aminophenol) (POAP) was formed by electropolymerization on well-aligned multi-walled carbon nanotubes (MWNTs). The electrochemical properties of POAP/MWNTs nanocomposites have been investigated by cyclic voltammetry in 1.0 M H2SO4 and 5 mM K-3[Fe(CN)(6)]/1 M KCl solutions. Platinum nanoparticles (PtNPs) were electrochemically deposited onto the POAP/MWNTs nanocomposites by potential cycling between +0.50 and -0.70 V at a scan rate of 50 mV sec(-1) in 0.1 M NaCl solution containing 5 mM Na2PtCl6. The electrocatalytic oxidation of methanol at the nanocomposites of PtNPs/POAP/MWNTs was studied in a 0.2 M H2SO4 solution. Compared to bare MWNTs and POAP modified glassy carbon electrodes, POAP/MWNTs electrode significantly enhances the catalytic efficiency of Pt nanoparticles for methanol oxidation. This improvement in performance is due not only to the high surface area and the fast electron transfer rate of nanotubes, but also to a decrease of the average particle size of Pt nanoparticles and an increase of the specific surface of electrodes in the presence of the POAP film.