Nickel selenide and nickel nanoparticles integrated into a three-dimensional N-doped porous carbon matrix (NiSe/Ni/NC) have been developed as bi-functional electrocatalysts for highly efficient and stable water splitting. The structure of as-prepared NiSe/Ni/NC are characterized by scanning electron microscopy, transmission electron micrographs, X-ray photoelectron spectroscopy, N-2 adsorption-desorption isotherms. In 1 M KOH electrolyte, as-prepared NiSe/Ni/NC delivers an overpotential of 77 mV for the hydrogen evolution reaction (HER) and 321 mV for the oxygen evolution reaction (OER) at the current density of 10 mAcm(-2). During the OER, NiSe/Ni/NC exhibits a better electrocatalytic performance compared to the state-of-the-art RuO2. Furthermore, when NiSe/Ni/NC is used as the water splitting, the potential can reach 1.6 V at 10 mAcm(-2). The high HER and OER catalytic activity of NiSe/Ni/NC originates from the mesoporous carbon matrix and synergetic effect between Ni, NiSe and the carbon matrix. In addition, when NiSe/Ni/NC is used as a bi-functional catalyst for HER and OER in alkaline media, it shows superior electrochemical performance to many other nickel selenide-based catalysts reported in the literature. (C) 2019 Elsevier Ltd. All rights reserved.