Highly durable FeNiSx/NiFe(OH)x electrocatalyst for selective oxygen evolution reaction in alkaline simulated seawater at high current densities

In this study, in-situ growing of FeNiSx/NiFe(OH)x on nickel form (NF) is successfully realized using a facile corrosion engineering process followed by a fast and mild sulfurization process, and applied as the anode for seawater electrolysis. The obtained anode requires only a low overpotential of 270 mV at a high current density of 100 mA cm−2 in alkaline simulated seawater and maintains mechanical stability at an industrial-level current density of 1 A cm−2 without corrosion. DFT calculations reveals that the FeNiSx/NiFe(OH)x has high selectivity towards oxygen evolution reaction (OER) against chlorine evolution reaction (ClER). For overall seawater electrolysis using it as the bifunctional electrocatalyst, the electrolyzer only requires a low cell voltage of 1.60 V at 10 mA cm−2 and can sustain stable at the industrial-level current density of 1 A/cm2 with a cell voltage of 2.81 V, achieving a high hydrogen productivity without the catalyst deterioration.