In Situ Growth of Sn-Doped Ni₃S₂ Nanosheets on Ni Foam as High-Performance Electrocatalyst for Hydrogen Evolution Reaction

Nickel sulfides have been widely employed as high-performance electrocatalysts for the hydrogen evolution reaction (HER) with high activity and low cost, and their performance could be tremendously promoted by elaborate design. Herein, we report a simple solvothermal route for the in situ growth of a three-dimensional network structure of Sn-doped Ni₃S₂, assembled by using ultrathin nanosheets on Ni foam. The ultrathin nanosheets with thicknesses of approximately 5–9 nm could provide more exposed active edges and a shorter electron transfer path. The Sn-doped sample exhibited efficient and durable electrocatalytic HER activity both in acid and alkaline conditions, much better than that of undoped Ni₃S₂ nanorods. Nyquist plots indicated that the electrochemical impendence reduced with the introduction of elemental Sn, which was another critical factor for the enhanced catalytic performance.