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 Fe 2 O 3 nanoparticles-anchored ultrathin Ni(OH) 2 nanosheets composites on nickel foam (Fe 2 O 3 /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.