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

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.