Operando Electrochemical Reduction Reconstruction Boosted Long-Term Overall Seawater Splitting

Abstract

Seawater electrolysis technology utilizes surplus renewable energy from maritime and coastal stations. However, the aggressive Cl^– in seawater caused the anodic kinetic restraints and metal dissolution deactivation, restricting the efficiency and durability of seawater electrolyzers. In this study, a convenient optimizing/retrieving strategy of the operando electrochemical reduction reconstruction (RR) has been proposed to reclaim the dissolved Fe ions from NiFe Foam by electrodeposition and decorate it onto the catalyst surface with the formation of electrophilic FeOOH. The operando electrochemistry techniques revealed that the RR-anchored FeOOH facilitated the anodic reorganization of amorphous γ-NiOOH, thus inhibiting chloride poisoning and boosting seawater oxygen evolution. Hence, the RR-optimized NiCoS NAs/NFF || NiCoS NAs/NFF showed a performance elevation (−265.4 μV h^–1) over 500 h of overall natural seawater splitting at 600 mA cm^–2 enabled by these strategic approaches. This investigation provided insight into the utilization of dissolved metal during overall seawater splitting and exhibited a promising future for long-term efficient electrolysis under harsh conditions.