Construction of nickel iron sulfide at ambient temperature on Fe foam for high-current overall water splitting†

The development of non-precious metal overall water splitting electrocatalysts under high current density is of utmost importance in feasible water splitting technology. Herein, we present an ambient temperature sulfuration strategy through in situ construction of iron nickel sulfide nanosheets vertically on 3D microporous iron foam. The synthesis conditions are simple and conducive to large-scale production. The FeNiS/IF nanosheets exhibit outstanding performance towards the HER and OER at large current densities, even in the order of 1000 mA cm⁻². Density functional theory calculations show that FeNiS/IF as a bimetallic sulfide exhibits superior HER activity in alkaline media due to the optimization of ΔG_H* and a more favorable water adsorption process.