Dual B and Fe doping boosts seawater oxidation on a Co3O4 nanoarray

Abstract

Direct seawater electrolysis has attracted intensive interest for the production of green hydrogen; however, the competing chlorine evolution reaction and oxygen evolution reaction lead to anode corrosion and thus limited durability. Here, B,Fe dual doping is proposed as an effective strategy to enhance its activity and the durability of the Co₃O₄ nanoarray supported on nickel foam (B,Fe-Co₃O₄/NF) for alkaline seawater oxidation. At an industrial-scale current density of 1000 mA cm⁻², the B,Fe-Co₃O₄/NF only needs an overpotential of 342 mV and operates stably for 500 h with negligible degradation and minimal active chlorine generation. Doping B and Fe synergistically enhances the catalytic activity, while B doping results in the formation of borate anions, which facilitate chloride ion repulsion.