In situ growth of NiSe@Co0.85Se heterointerface structure with electronic modulation on nickel foam for overall water splitting

Constructing heterointerface engineering has becoming an effective and general strategy for developing highly efficient and durable nonnoble electrocatalysts for catalyzing both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this work, we synthesized a self-supporting heterogeneous NiSe@Co 0.85 Se/NF electrocatalyst using a facile in situ selenization of transition metal precursors that coated on the nickel foam (NF) in polyol solution. The NF was used as both conductive substrate and nickel source, ensuring superior electronic conductivity for catalyzing. The NiSe@Co 0.85 Se/NF exhibited remarkable bifunctional electrocatalytic activities with HER overpotential of 168 mV and OER overpotential of 258 mV to achieve 10 mA·cm −2 . The water splitting system using NiSe@Co 0.85 Se/NF as both anode and cathode electrodes achieved a current density of 10 mA·cm −2 at 1.61 V with nearly 100% faradaic efficiency and impressively long-term stability. The efficient bifunctional catalytic performance of NiSe@Co 0.85 Se/NF should be attributed to the electronic modulation and synergistic effect between NiSe and Co 0.85 Se, the intrinsic metallic conductivity and the enlarged active sites exposure. This work provides a facile method for developing heterogeneous bifunctional catalysts for advanced electrochemical energy conversion technologies. Graphic abstract