Zirconium-Incorporated Cobalt Phytate for Efficient and Durable Seawater Electrolysis

Electrocatalytic seawater splitting provides a promising strategy for hydrogen production. However, chlorine anions in seawater can cause undesirable side reactions, resulting in a low efficiency and unsatisfied durability. Herein, we report the rational incorporation of Zr 4+ into cobalt phytate (Zr-CoPA) for efficient and durable seawater electrolysis. The Zr 4+ sites could effectively regulate the surface adsorbates and the reaction pathway, achieving a high current density of 0.1 A cm −2 at 1.59 V with over 700 h of stability in a seawater electrolysis system. The surface Zr 4+ sites exhibit a strong affinity for OH − and an apparent repulsion for Cl − . In addition, the incorporated Zr 4+ can induce a strong crystal field effect, which polarizes the lattice oxygen to form accessible oxygen nonbonding (O NB ) states for boosting the activation of lattice oxygen. The resultant oxygen vacancies during seawater oxidation can be rapidly offset by surface hydroxyl species enriched by Zr 4+ . The involvement of lattice oxygen for O–O bond formation averts the high-energy potential-determining step in the traditional water nucleophilic attack pathway in water oxidation, which further avoids chlorine oxidation that is favorable under high potentials.