One step in-situ synthesis of Ni3S2/Fe2O3/N-doped carbon composites on Ni foam as an efficient electrocatalyst for overall water splitting

Abstract The design and synthesis of electrocatalyst with rich catalytic active sites are of great significance for clean hydrogen energy production from water splitting. Herein, the composites of Ni3S2/Fe2O3/N-doped carbon on Ni foam (Ni3S2/Fe2O3/NC/NF) were prepared by a facile one-step thermal process and were used as a binder-free electrode for overall water splitting. Specifically, the Ni3S2/Fe2O3/NC/NF-600 electrode exhibits excellent catalytic activity towards oxygen evolution reaction (OER) with a small overpotential of 188 mV at current density of 52 mA cm−2 and hydrogen evolution reaction (HER) with overpotential of 78 mV at current density of 10 mA cm−2. An overall water splitting device comprised of Ni3S2/Fe2O3/NC/NF-600 electrodes displays low voltages of 1.478 and 1.605 V to drive current densities of 10 and 100 mA cm−2, respectively, and can even induce overall water splitting only by a 1.5 V of dry battery. The advantages of the Ni3S2/Fe2O3/NC/NF-600 electrode include strong coupling of the composite with Ni foam skeleton, high electronic conductivity, unique hierarchical structure and abundant heterointerfaces for catalytic active sites, all of them contribute to the superior OER, HER, and overall water splitting performances. Our results can inspire a new method to design and synthesize advanced electrochemical catalysts for overall water splitting.