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/cm2 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/cm2. 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/cm2 in simulated and natural seawater electrolytes, respectively. This electrolyzer holds significant promise for practical seawater electrolysis.