Dendritic palladium decorated with gold by potential pulse electrodeposition: Enhanced electrocatalytic activity for H2O2 electroreduction and electrooxidation

Dendritic Au@Pd nanocomposite is uniformly electrodeposited on carbon fiber cloth via a two-step potential pulse technique. The electrode (Au@Pd/CFC) is characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractometer. It shows a unique open three dimensional structure allowing the full utilization of electrocatalyst. Au is uniformly distributed on the surface of Pd nano-dendrites. H2O2 electrooxidation in KOH solution and electroreduction in H2SO4 solution on the dendritic Au@Pd/CFC electrode are studied by linear sweep voltammetry, chronoamperometry and electrochemical impedance. The electrode exhibits a remarkably higher catalytic activity for both H2O2 electrooxidation and electroreduction than the Pd/CFC electrode. The effects of H2O2, KOH and H2SO4 concentration on the catalytic performance were investigated and the suitable ratios of [H2SO4]/[H2O2] and [KOH[/[H2O2] are determined to be 1 and 4. The cell using it both as the anode and cathode exhibits a much higher performance than those reported in the literatures, that an open circuit voltage is as high as 0.9V and the peak power density can reach 20.7 mW cm(-2) at 20 degrees C. (C) 2013 Elsevier Ltd. All rights reserved.