ELECTROCATALYTIC ACTIVITY OF A GRAPHITE-BASED PT ELECTRODE MODIFIED WITH METAL-OXIDES TOWARDS METHANOL OXIDATION

The electro-oxidation of CH3OH was carried out on oxide-modified Pt electrodes using graphite as the substrate in 0.5 M H2SO4. A graphite-based Pt electrode modified with In + Pb mixed oxide exhibited a considerable level of electrocatalytic activity towards methanol electro-oxidation, showing a very low zero-current potential, i.e. 95 mV (vs. RHE), which is rather close to the theoretical oxidation potential (approximately 30 mV in acidic solution). Further, an electrode modified with Au in addition to In + Pb mixed oxide exhibited a higher electrocatalytic activity, i.e. a higher oxidation current and a more negative zero-current potential (70 mV), than that of the electrode modified with In + Pb mixed oxide alone. However, the oxidation current did not increase rapidly with the electrode potential and the oxides were not sufficiently stable in the background solution, 0.5 M H2SO4. The possibility of using mixed oxides having higher electrical conduction and sufficient stability in acidic solution as surface modifiers of fuel cell electrodes was indicated.