An efficient Ni3S2–Ni electrode constructed by a one-step powder metallurgy approach for the hydrogen evolution reaction

Abstract

The production of green hydrogen has become one of the important parts of hydrogen energy in achieving zero carbon emission, and water electrolysis is an efficient and renewable strategy to produce green hydrogen. In recent years, many researchers have focused on the study of high-efficiency hydrogen evolution catalysts for water electrolysis. Apart from noble metal-based catalysts, non-noble Ni-based materials have been used to catalyze the hydrogen evolution reaction. However, the preparation of traditional Ni-based electrodes consists of multi-step synthesis processes. Here, a simple, time-saving and low-cost one-step powder metallurgy process using Ni and nano S powder as raw materials was innovatively proposed to prepare a mechanically stable and highly active Ni₃S₂–Ni electrode. Numerous Ni₃S₂ nano protuberances on the skeleton surface and strong metallurgical bonding between inter-connected Ni networks formed during the integrated in situ sintering process significantly improve the catalytic performance and durability. As a result, the Ni₃S₂–Ni-500-20 electrode exhibits high hydrogen evolution activity with an overpotential of only 157.8 mV at a current density of 100 mA cm⁻² as well as superior durability with a constant current density of 260 mA cm⁻² for 225 h. This work provides a feasible method for the one-step synthesis of transition metal compound-metal self-supporting water splitting electrodes with low-cost and high efficiency.