Pd–Cu/C electrocatalysts synthesized by one-pot polyol reduction toward formic acid oxidation: Structural characterization and electrocatalytic performance

Abstract

Carbon supported Pd–Cu nanoparticles have been synthesized via a facile one-pot polyol reduction process (simplified hereafter as Pd–Cu/C-polyol), as electrocatalysts toward formic acid oxidation (FAO). The as-synthesized Pd–Cu/C-polyol catalysts are structurally characterized by TEM, XRD, X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) measurements. Notably, an atomic level understanding of the as-prepared bimetallic nanocatalysts is achieved by XAS, providing insights into both the interatomic distances and the coordination numbers information. The results suggest that Pd–Cu nanoalloy particles are highly dispersed on Vulcan XC-72 carbon and enriched with Pd in their skin layers. Electrochemical measurements indicate that Pd1Cu1/C-polyol exhibits the best electrocatalytic performance towards FAO in terms of Pd-mass activity and durability among commercial Pd/C, Pd2Cu1/C and Pd1Cu1/C. The comprehensive structural characterizations enable a better understanding of the enhanced electrocatalytic performance of the bimetallic catalysts: the addition of Cu is suggested to lower appropriately the d-band center of Pd and increase the electrochemical active surface area of the Pd–Cu/C nanocatalysts.