Catalytic properties of Pd nanoparticles supported on Cu2O microspheres for hydrogen peroxide electroreduction

Abstract

Cuprous oxide (Cu₂O) were synthesized by a wet-chemical approach in aqueous solution and Pd electrocatalysts supported on cuporus oxide (Pd/Cu₂O) and Vulcan XC-72 (Pd/C) were synthesized both via modified sodium borohydride reduction method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) methods were used to characterize the surface morphology and composition of the Cu₂O nanoparticles and the catalysts. Linear sweep voltammetry (LSV) and chronoamperometry (CA) were employed to evaluate the activity and stability of the catalysts. The results showed that the Cu₂O nanoparticles were spherical with a smooth surface and the average diameter was about 600 nm. Pd nanoparticles decorated the surface of the Cu₂O nanospheres and agglomerated slightly and the average size of the Pd nanoparticles was about 10 nm. A certain amount of copper oxide and metallic Cu were formed during the preparation of the Pd/Cu₂O catalyst. The Pd catalyst supported on cuporus oxide (Pd/Cu₂O) showed a superior performance to the catalyst supported on Vulcan XC-72, which was attributed to two reasons. One was that the Pd/Cu₂O catalyst had a larger surface area and the other was that all of the support material components, Cu₂O itself, copper oxide and the metallic Cu formed in the process of catalyst preparation, had activity for the H₂O₂ electroreduction reaction to a certain extent.