Construction of S-modified Amorphous Fe(OH)₃ on NiSe Nanowires as Bifunctional Electrocatalysts for Efficient Seawater Splitting

Seawater electrolysis is valuable for hydrogen production, but there are significant challenges such as severe Cl – corrosion and competition reaction of the chlorine evolution reaction (CER) due to high Cl – concentrations. Here, a core–shell structure was developed on the nickel foam substrate, consisting of a sulfur-modified amorphous Fe(OH) 3 layer on top of a crossing NiSe nanowire (named S–Fe(OH) 3 /NiSe/NF). The S–Fe(OH) 3 /NiSe/NF electrode demonstrates outstanding catalytic performance for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in simulated and natural alkaline seawater electrolytes. The overpotentials at 100 mA/cm 2 for the OER in simulated and natural alkaline seawater electrolytes are 234 and 232 mV, respectively. For HER, the values are 331 and 341 mV, respectively, at a current density of 100 mA/cm 2 . When S–Fe(OH) 3 /NiSe/NF serves as both the anode and cathode, the electrolyzer demonstrates excellent performance with voltages of 1.85 and 1.87 V at 100 mA/cm 2 in simulated and natural seawater electrolytes, respectively. This electrolyzer holds significant promise for practical seawater electrolysis.