Direct Electrochemical Seawater Splitting for Green Hydrogen and Artificial Reefs

The electrochemical splitting of abundant seawater using renewable electricity to generate green hydrogen holds a great promise for energy transport and storage. However, direct seawater electrolysis suffers from side reactions and degradation of electrodes due to impurities. Here, we demonstrate a direct electrochemical seawater splitting device that uses only electricity and air. The seawater was desalinated first by oxygen reduction, which created an alkaline environment and concurrently captured CO 2 to remove Ca and Mg ions. Simultaneously, artificial reefs could be formed. The softened seawater was immediately utilized to produce hydrogen. This proof of concept shows that seawater splitting could be coupled with value-added processes, allowing for the direct utilization of seawater without pretreatment or purification and circumventing the challenges posed by impurities and cost. With the simultaneous production of H 2 and artificial reefs, CO 2 elimination, and powered solely by renewable electricity, this strategy provides an approach to seawater splitting for sustainable H 2 production.