ELECTROCATALYTIC ACTIVITIES OF GRAPHITE-SUPPORTED PLATINUM-ELECTRODESFOR METHANOL ELECTROOXIDATION

Electrooxidation of methanol in 1 M NaOH at 30 degrees C was studied o n graphite-supported platinum electrodes prepared both in hydrogen and in air at various temperatures. Heating in hydrogen always; produced higher surface area of Pt, and hence greater mass activity, than in ai r at a particular temperature. Nevertheless, both the graphite-support ed platinum electrodes exhibited almost the same specific activity as a smooth Pt electrode for methanol electrooxidation irrespective of th e preparation conditions. This indicates that the difference in mass a ctivity is due to different surface areas produced by the different pr eparation methods. The Tafel slope of 1 10 mV decade(-1) on all the el ectrodes studied indicated that the first charge transfer process was the rate-determining step.