▎ 摘　　要

With decreasing fossil fuels and rising environmental issues, harvesting energy in a large amount and in a clean way has been a great challenge for the whole world. Developing the efficient electrocatalysts with less expense and achieving the better electrocatalytic behavior for oxygen evolution reaction (OER), oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is very essential for extensive commercialization of fuel cells, water electrolyzers and metal air batteries. In the same pursuit, herein, we report a bifunctional coral-like NiCo2O4 nanostructure supported on reduced graphene oxide (rGO) sheets, which was prepared by a facile, controlled hydrothermal reaction protocol. The structural, morphological and electrochemical characterizations have been carried out to explore the properties of this nanocomposite. The unique morphology, large electroactive surface area and the synergistic effect of the metal ions on the electrocatalytic activity makes this material a suitable candidate for electrochemical water splitting. The low onset potential, high current density, lower Tafel slope and long-term stability in both HER and OER has been shown by rGO-NiCo2O4 coral like nanostructure, which reveals the high catalytic activity of this material, underlying the finding and importance of current work. (C) 2018 Elsevier B.V. All rights reserved.