Electrocatalytic behavior of Pt-modified polyaniline electrode for methanol oxidation: Effect of Pt deposition modes

Platinum dispersed in polyaniline film is a better catalyst than bulk platinum for methanol electrooxidation in sulfuric acid solution. The effect of deposition modes of platinum particles on their electrocatalytic activity has been studied. Several electrodeposition methods, including constant potential, cyclic potential and double potential step, have been applied to characterize the performance of different electrodeposition modes. Besides the variation of the electrodeposition methods, rotating disk electrode technique is applied to disperse Pt particles under the control of convection-diffusion condition. The results show that the enhanced electrocatalytic activity may be due to the dispersion of Pt particles in the polyaniline film matrix and the synergistic effects between the dispersed Pt particles and the polyaniline film. Variables related to reaction kinetics, such as mass transport of species, concentration of methanol and acidity of solution, are investigated and reaction mechanism for methanol oxidation is discussed.