Fe and Co dual-doped Ni3S4 nanosheet with enriched high-valence Ni sites for efficient oxygen evolution reaction

•Fe and Co dual doped Ni3S4 exhibits efficient catalytic performance for OER.•Dual doping induce the interaction of electrons and expose more active sites.•High content of Ni3+ is beneficial to the electron transfer during the OER.•The FeCo-Ni3S4//MoNi4 couple can reach 10 mA cm−2 at 1.47 V in1.0 M KOH. Transition metal compound catalysts with high efficient and stable performance have attracted extensive attention of researchers. In this study, dual cation doped Ni3S4 nanosheets loaded on nickel foam were prepared by two step hydrothermal method. Co and Fe dual doping can induce the internal electronic interaction of the catalyst, thus exposing more active sites. Meanwhile, high Ni3+ content enhances the chemisorption of OH−, which is conducive to the transfer of electrons in the reaction process. The electrochemical test results show that Co and Fe doped Ni3S4 have better electrocatalytic performance for oxygen evolution than single cation doped and pure Ni3S4. In 1.0 M KOH solution, the FeCo-Ni3S4 electrode exhibits a remarkable oxygen evolution reaction activity with low overpotentials of 230 mV at 20 mA cm−2 and 279 mV at 100 mA cm−2. The water-alkali electrolyzer using FeCo-Ni3S4 as anode achieves stable overall water splitting with a low potential of 1.47 V at 10 mA cm−2. This work will provide a new direction and guidance for the synthesis and application of transition metal sulfide catalysts.