Ni3S2 Nanosheets in Situ Epitaxially Grown on Nanorods as High Active and Stable Homojunction Electrocatalyst for Hydrogen Evolution Reaction

Development of efficient noble metal-free electrocatalysts for accelerating the sluggish kinetics in the hydrogen evolution reaction (HER) has received a great deal of attention in electrolytic water splitting. Herein, we present a facile one-step solvothermal strategy for controllably constructing the homojunction structures of Ni3S2 nanosheets in situ epitaxially grown on nanorods by using Ni foam as self-support substrate and nickel resource (Ni3S2/NF). In the synthesis, cetyltrimethylammonium bromide and hydrazine hydrate are used to control the formation of nanorods and nanosheets, respectively. The special 3D Ni3S2 nanorods@nanosheets homojunction could provide plentiful catalytically active sites; meanwhile, the intimate contact between Ni3S2 and Ni foam could enhance the long-term stability. The inevitable sulfur vacancies in the Ni3S2 could tune electronic structure of the surface and enhance the catalytic activity. The synergistic effect leads to the as-prepared Ni3S2/NF exhibiting a superior HER performance with eta(onset) of 10.8 mV, eta(10) of 48.1 mV, and a Tafel slope of 88.2 mV dec(-1) in alkaline electrolyte. Furthermore, it can continuously work for 10 000 cycles with negligible activity loss. This work opens a new avenue for designing and synthesizing noble metal-free electrocatalysts with high activity and good stability toward HER.