Synthesis of Ni-Doped Copper Cobalt Sulfide Nanoparticles and its Enhanced Properties as an Electrocatalyst for Hydrogen Evolution Reaction

Developing high-efficiency electrocatalysts for hydrogen evolution reaction (HER) is vitally important in electrochemical water splitting technology. Herein, ultra-small Ni-doped CuCo2S4 nanoparticles (NCCS NPs) are easily achieved in a single step by a facile hydrothermal method. The investigations, using powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and TEM, reveal that the as-prepared NCCS products are composed of a large number of uniform nanoparticles with sizes ranging from 20 to 50 nm. Triethanolamine is of vital importance for the formation of the NCCS NPs during the sulfidation process. As a promising electrocatalyst for HER, the NCCS NPs not only display a lower overpotential at 10 mA cm(-2) current density than that of bare CuCo2S4 nanoparticles (CCS NPs), but also show better long-term durability than CCS NPs during the galvanostatic electrolysis. Furthermore, Ni doping for NCCS NPs are proved to play a particular important role in the HER process. This finding provides a strategy in compositional tuning of mixed polymetallic sulfides catalysts for electrochemical hydrogen evolution.