Hydrolysis assisted in-situ growth of 3D hierarchical FeS/NiS/nickel foam electrode for overall water splitting

Non-noble-metal based catalysts for overall water splitting have attracted widespread attention. Herein, we report a Fe(II) hydrolysis reaction assisted in-situ etching and growth method for the design of Fe2O3 nanoparticles-anchored ultrathin Ni(OH)2 nanosheets composites on nickel foam (Fe2O3/Ni(OH)2/NF), followed by solvothermal sulfidation conversion into FeS/NiS/NF electrode. As-prepared FeS/NiS/NF electrode possesses low overpotentials of 203 mV and 144 mV to achieve a current density of 10 mA cm−2 in 1.0 M KOH for OER and HER, respectively. FeS/NiS/NF directly serves as both anode and cathode to assemble a two-electrode water electrolyzer, which only requires a voltage of 1.618 V to afford water-splitting current density of 10 mA cm−2 in 1.0 M KOH. Additionally, this water splitting device can also be driven by using photovoltaic solar panels. This work provides a new strategy to tailor the components and structure of the catalyst and thus to improve electrocatalytic performance. [Display omitted] •Overall water splitting electrode of FeS nanoflowers/NiS nanosheets/Ni foam.•Binder-free electrodes.•Fe2+ hydrolysis-assisted synthesis of ultrathin Ni(OH)2 nanosheet, i.e., Fe2O3/Ni(OH)2/NF precursor.•Excellent performance: Overpotential for OER (η10 = 203 mV) and HER (η10 = 144 mV).