Electrodeposited Pd–MoOx catalysts with enhanced catalytic activity for formic acid electrooxidation

Pd–MoOx catalysts supported on glassy carbon electrode were co-deposited using cyclic voltammetry. The influence of two key deposition parameters (i.e. scanning potential range and concentration of sodium molybdate in the electrolyte) on the catalysts was investigated by X-ray diffraction, energy dispersive X-ray spectroscopy, element analysis mapping, scanning electron microscopy, X-ray photoelectron spectroscopy and typical electrochemical measurements, respectively. It was found both of the parameters had great effect on the morphology, chemical states, composition and electrochemical performance of the catalysts. By tuning the electrodeposition parameters, we found the optimal condition to prepare the catalysts. The as-prepared catalysts showed much improved catalytic activity and stability for formic acid electrooxidation. The enhanced performance can be attributed to the fine porous structure composed of small particles, hydrogen spillover effect and unique element distribution (different composition between surface and bulk).