Highly active and dual-function self-supported multiphase NiS-NiS2-Ni3S2/NF electrodes for overall water splitting

The strategy of compatibly integrating cost-effective HER-and OER-active materials in a well-designed manner is expected to obtain bifunctional electrocatalysts for overall water splitting. We extend this strategy to a bifunctional self-supported electrode for water splitting to achieve a dynamic balance between the HER and OER through a fast, simple and economical fabrication process. The electrocatalytic activities of the self-supported multiphase NiS-NiS2-Ni3S2/NF (m-NiSx/NF) electrodes toward water splitting are obtained and optimized by modulating the quantity of sulfur powder during the reaction procedure. As a result, the self-supported m-NiSx-0.5/NF electrode exhibits overpotentials of 143 mV and 137 mV to afford a current density of 20 mA cm(-2) for the OER and HER in 1.0 M KOH aqueous solution, respectively. Impressively, overall water splitting with 10 mA cm(-2) at a low voltage of 1.46 V is achieved using self-supported m-NiSx-0.5/NF as both the anode and cathode electrodes, surpassing the performance of nearly all the recently reported nonprecious electrocatalysts for overall water splitting.