Facile syntheses and electrocatalytic properties of porous Pd and its alloy nanospheres

Pd-based catalysts are of great interest both for fundamental research and applications. It still remains a challenge to develop reliable and versatile approaches to prepare Pd-based nanostructures with higher performance and better stability. In this article, a facile solution route has been developed to prepare Pd nanospheres, as well as Pd-Pt, Pd-Ag and Pd-Pt-Ag alloy nanospheres. SEM and TEM investigations revealed that the as-prepared nanospheres were three-dimensionally interconnected porous networks with primary nanoparticles as building blocks. The chemical composition of these nanospheres can be easily adjusted by controlling the molar ratio of precursors. Electrochemical measurements indicated that the electrocatalytic activity of these nanospheres towards formic acid oxidation depended on the composition of the nanospheres. By judiciously adjusting the composition of the Pd based alloy nanospheres, the performance of the Pd based catalysts, i.e., the onset potential of the formic acid oxidation, the corresponding peak current density and the ability to tolerate CO, can be optimized.