Tuning of crystal phase of nickel telluride nanosheets to construct superior electrocatalyst for hydrogen evolution

It is of great significance to develop low cost, high-efficiency and environment-friendly electrocatalysts for hydrogen evolution reaction (HER) from water splitting. Herein, nickel telluride nanosheets grown on Ni Foam (NF) with three different crystal phases (NiTe, Ni 2.6 Te 2 and Ni 2.86 Te 2 ) are fabricated by one-step hydrothermal tellurization followed annealing process. The non-stoichiometric Ni 2.86 Te 2 /NF exhibits superior electrocatalytic HER performance compared to the NiTe/NF and Ni 2.6 Te 2 /NF, which is comparable to the state-of-the-art 20 wt% Pt/C catalyst at high current density. The Ni 2.86 Te 2 /NF only requires an overpotential of 348 mV to drive the current density of 200 mA cm −2 in a 1.0 M KOH electrolyte. Similarly, The Ni 2.86 Te 2 /NF delivered current densities of 200 mA cm −2 at the overpotential of 279 mV in 0.5 M H 2 SO 4 . Such excellent performance could be ascribed to the fast electron transfer and positive shift of d d-band center from its rich defective effect of crystal phase transition, as well as to the exposure of active sites provided by the two-dimensional nanosheets with large specific surface area. This work provides valuable insights for the rational modulation of the crystal phase on the nickel telluride for catalyzing HER.