Corrosion-resistant MoO₃/Fe₂O₃/MoS₂ heterojunctions stabilize OH‾ adsorption for efficient light-assisted seawater electrooxidation

Abstract

Direct seawater electrolysis holds promise for sustainable hydrogen production, yet challenges such as severe chlorine corrosion on the anode and high energy barriers for oxygen evolution reaction (OER) limit its operational time and efficiency. Herein, we present MoO3/Fe2O3/MoS2 heterojunctions to mitigate chlorine-induced corrosion and achieve effective photoelectric synergy. The in situ leached MoO42– and SO42– inhibitors reduce Cl– adsorption, thereby ensuring high OER selectivity, while the MoO3/Fe2O3/MoS2 balances the repelling effects of these inhibitors, facilitating OH– adsorption and widening the overpotential gap between water oxidation and chlorine oxidation. The MoO3/Fe2O3/MoS2 catalyst outperforms its Fe2O3 counterpart in terms of lifespan, maintaining stability at 100 and 300 mA cm–2 for 100 and 500 h, respectively. Additionally, built-in electric fields formed at the interfaces lower interfacial resistance and extend the lifetime of photogenerated carriers by 1.47-fold, allowing for a 20.4% increase in seawater OER current density under light irradiation. Our findings offer a viable strategy for designing high-performance electrocatalysts for light-assisted seawater electrolysis.