Pulse electrodeposition of NiCoS on carbon paper for electrochemical hydrogen evolution reaction

Abstract

NiCoS has good conductivity, and the sulfur it contains is known to improve the activity for hydrogen evolution reaction. Thus NiCoS has recently attracted much attention as a catalyst for hydrogen evolution reaction catalyst in neutral-pH water electrolysis. In this study, NiCoS was fabricated using pulse electrodeposition method and the effect of off time on the composition, morphology, and hydrogen evolution reaction activity was investigated. The physical and chemical characteristics of the catalyst were analyzed using field emission scanning electron microscopy, X-ray diffractometry, electrochemical impedance spectroscopy, etc. It was observed that the surface area of NiCoS, the sulfur content, and hydrogen evolution reaction activity of NiCoS increased together as the off time increased at a constant on time. The NiCoS with the highest sulfur content, produced by pulse electrodeposition, showed overpotentials of 262 and 285 mV to deliver current densities of 10, 50 mA/cm<sup>2</sup>, respectively, in the neutral pH region.