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

•2D interconnected NiTe/NF nanosheets was prepared by one-step hydrothermal method.•Annealing temperatures have an effect on crystal phase change and HER performance.•It leads to a positive shift of the d-band center on non-stoichiometric Ni2.86Te2.•The Ni2.86Te2/NF exhibits superior HER performance compared to NiTe/NF.