Challenges and strategies of chlorine inhibition in anode systems for seawater electrolysis

Seawater electrolysis for green hydrogen production is one of the key technologies for achieving carbon neutrality. However, in anode systems, the chloride ions (Cl⁻) in seawater will trigger an undesired chlorine evolution reaction (CER) that competes with an oxygen evolution reaction (OER), resulting in inferior OER activity and selectivity. Besides, the corrosive Cl⁻ and its derivative products will corrode anodes during seawater electrolysis, leading to poor stability. Therefore, great efforts have been devoted to developing efficient strategies for chlorine inhibition to improve the activity, selectivity, and stability of anode materials. Herein, focusing on chlorine inhibition, we present a mini review to comprehensively and concisely summarize the recent progress in anode systems for boosting seawater electrolysis. In particular, two strategies of physical and chemical regulation to inhibit Cl⁻ are summarized in some representative cases. Finally, some challenges and future opportunities in anode systems for seawater electrolysis are prospected. This mini review aims to shed light on designing highly efficient anode materials for seawater electrolysis.