Electrocatalytic oxidation of four low-carbon alcohols at Pd nanoparticle modified indium tin oxide electrode.

A Pd nanoparticle modified indium tin oxide (Pd NPs/ITO) electrode was prepared by cyclic voltammetry (CV) methods. The surface morphology of the modified electrode was characterized by scanning electron microscopy (SEM). The Pd NPs/ITO electrode exhibits excellent electrocatalytic activity towards the oxidation of four low-carbon alcohols including methanol, ethanol, propanol and isopropanol in alkaline electrolyte at room temperature. The effects of reactant concentration and scan rate on the alcohols electrocatalytic oxidation at the Pd NPs/ITO electrode were discussed in detail and the electrocatalytic oxidations of four alcohols are confirmed as diffusion-controlled process from their similar CV characteristic. These low-carbon alcohols or their dissociation products are adsorbed on the surface of Pd NPs/ITO electrode, and simultaneously inhibit the adsorption and desorption of hydrogen, leading to the dominant of alcohol oxidation. The oxidation processes of four low-carbon alcohols are irreversible on Pd NPs/ITO electrode. The activity order of alcohol oxidation on Pd NPs/ITO electrode is identified as ethanol > propanol > methanol > isopropanol. The four alcohols can be easily identified from their positions of oxidation peak.