The utilization of ions in seawater for electrocatalysis

Electrocatalysis in water offers a sustainable pathway for synthesizing hydrogen and hydrocarbons, leveraging water as a source of protons and hydroxides. However, the inherent presence of ions in water significantly influences the adsorption of active species, often disrupting electrocatalytic performance. While strategies have advanced to repel interfering ions and mitigate their adverse effects in seawater electrocatalysis, recent findings reveal that certain seawater ions can enhance electrocatalytic processes. This enhancement occurs either by promoting the adsorption of crucial reaction intermediates or by directly participating as reactants. Despite this potential, the underlying mechanisms and practical applications of these ion-involved reactions remain poorly understood and lack systematic evaluation. This review provides a timely appraisal of electrochemical reactions that strategically utilize seawater ions. It highlights recent advancements in methodologies and strategies within this emerging field. Firstly, we delve into the designs and mechanisms enabling chloride utilization in various electrocatalytic reactions. Next, we discuss intelligent protocols for sodium utilization, including asymmetric designs, aqueous alternating and cascade seawater electrocatalysis. Subsequently, we elucidate the critical role of local pH limitations and the impact of external forces on catalysts for direct seawater electrocatalysis. Finally, the electrochemical extraction of valuable resources such as uranium and lithium is summarized, with a focus on innovative electrode modifications and optimized cell configurations.