Heterostructured Ni(OH)2/Ni3S2 supported on Ni foam as highly efficient and durable bifunctional electrodes for overall water electrolysis

Development of efficient, stable and robust bifunctional electrodes is important for the industrial application of water electrolysis technologies for renewable hydrogen production. Here, we report the fabrication of heterostructured Ni(OH)2 nanosheets/Ni3S2 nanoneedles grown on Ni foam, Ni(OH)2/Ni3S2/NF, as highly active and mechanically strong bifunctional electrode for overall water splitting. The results indicate that heterostructured Ni(OH)2/Ni3S2 interfaces are the reactive center for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The redistribution of electrons and formation of the Ni+ and S- active species serve as the hydroxyl and proton acceptors and significantly promote the transformation of intermediate species and charge transfer processes in both the OER and HER. The Ni(OH)2/Ni3S2/NF electrode shows overpotentials as low as 252, 279 and 319 mV to reach 30, 50 and 100 mA cm-2, respectively, for OER and 48, 79 and 185 mV to achieve 10, 20 and 100 mA cm-2, respect...