A comparative study on ethanol oxidation behavior at Pt and PtRh electrodeposits

A comparative study on the catalytic activity for ethanol oxidation of electrodeposited platinum and platinum–rhodium alloys has been carried out. Voltammetry, polarisation study and electrochemical impedance spectroscopy were used for the characterization of the electrodes. A study on the temperature-dependence of the electrocatalytic activities afforded the determination of apparent activation energies for ethanol oxidation. A pronounced effect of catalyst composition on ethanol oxidation was observed. Of the different atomic composition of PtRh alloys studied, the best ethanol oxidation behavior was observed for the Pt74Rh26 electrode. The results indicate that the enhancement in electrocatalytic activity for this PtRh catalyst in comparison to Pt itself can be ascribed to an improvement of C–C bond dissociation rather than to a bifunctional mechanism.