V and Fe dual-doping modulated the electronic structures of Ni3S2/Ni(OH)2 for ampere-level seawater oxidation

The development of versatile oxygen evolution reaction (OER) electrocatalysts for ampere-level seawater electrolysis holds enormous promise for clean energy generation. Still, it is hindered by the competing chlorine evolution and severe chloride corrosion. Herein, the V and Fe dual-doped Ni3S2/Ni(OH)2 (VFe-Ni3S2/Ni(OH)2) heterostructure was fabricated on nickel foam as an OER catalyst for direct seawater electrolysis. The dualdoping of V and Fe optimizes the electronic structure cooperatively, improves conductivity, and enriches active sites of Ni3S2/Ni(OH)2, boosting OER performance at ampere-level current density. The optimal electrode V0.03Fe-Ni3S2/Ni(OH)2 requires only 385 mV overpotential to arrive 1 A/cm2 and works stably for over 100 h at 100 mA/cm2 in seawater electrolyte. The assembled electrolyzer V0.03Fe-Ni3S2/Ni(OH)2||Pt/C exhibited a cell voltage of 1.52 V at 10 mA/cm2 with a noteworthy stability of 100 h at 100 mA/cm2 for seawater electrolysis, providing huge potential for hydrogen production from seawater.