Modulating electronic structure of CoSe2 by Ni doping for efficient electrocatalyst for hydrogen evolution reaction

Developing robust and efficient non-noble electrocatalysts for the hydrogen evolution reaction (HER) is paramount for sustainably producing hydrogen fuel from electrochemical water splitting. Engineering morphology and chemical composition are significant for fabricating electrocatalysts with superior activity and durability. Herein, novel Ni-doped CoSe2 composites are prepared by a facile one-step hydrothermal method. The optimized 1T-phase Co0.75Ni0.25Se2 shows excellent HER performance, exhibiting overpotential of as low as 172 mV at 10 mA·cm–2 and a small Tafel slope of 32.4 mV·dec–1 in 0.5 mol·L−1 H2SO4 solution, approaching that of commercial Pt/C electrocatalyst (30.7 mV·dec–1). Furthermore, the electrocatalyst possesses superior long-term stability under acidic condition. Physicochemical measurements indicate that the homogeneous nanoparticles morphology, the unique electronic structure, and the 1T-phase are responsible for its superior HER performance. This work comes up with a promising strategy in synthesizing other earth-abundant and low-cost catalysts for industrial applications.