Facile green synthesis of palladium quantum dots@carbon on mixed valence cerium oxide/graphene hybrid nanostructured bifunctional catalyst for electrocatalysis of alcohol and water

The development of an efficient catalyst for proton exchange membrane fuel cells is presently a challenging and pressing need. Enhanced activity is expected to occur if the interactions between the catalytic metal and the support are improved. Herein, we report the eco-friendly green solid state synthesis of palladium quantum dots@carbon on mixed valence cerium oxide nanoparticles/reduced graphene oxide hybrid (PdQD@C-CeOx/RGO) nanocomposites. We also detail their notable performance in the electrocatalysis of ethylene glycol and water in alkaline medium. The palladium nanoparticles, which are 2-5 nm in size, are formed in a fast manner. In terms of catalytic activity, the low-quantity palladium nanoparticle (5 wt%)@carbon-cerium oxide/reduced graphene oxide on the electrode exhibits the highest forward anodic peak current density (10 mA cm^-2) compared with the Pd/CeOx and Pd/RGO nanocomposite electrodes. The cerium oxide/reduced graphene oxide functions as both the support and in assisting the electrooxidation reactions towards removal of poisonous intermediates formed during the electrooxidation of ethylene glycol. This work could provide new insights into the simple fabrication of high-performance catalytic electrodes for fuel cell applications.