Alleviating OH Blockage: Asymmetric Adsorption Configuration of Co–OH–M (d 10 ) for Seawater Electrolysis

Cobalt-based phosphides, sulfides, and selenides (Co-Xides, X = P, S, Se) are promising corrosion-resistant anode catalysts for seawater electrolysis, which stems from the reconstruction of oxyanion layers (PO43–, SO42–, SeO42–) that electrostatically repel Cl– adsorption. However, in the restructured CoOOH species, the OH species is overstabilized by a rigid dual-site bridging configuration (Co–OH–Co), which significantly increases the energy barrier for the subsequent OER steps. To overcome the limitation of high barrier for the rate-determining step of OER, d10-configured elements M (M = In, Sb, Sn) are introduced to construct an asymmetric d–p–p configuration Co–OH–M (d10) that breaks the excessive stabilization of OH and weakens OH adsorption by leveraging the mismatch in orbital energy and symmetry. In situ characterization and density functional theory calculations confirmed that the asymmetric Co–OH–M (d10) adsorption configuration reduced the surface OH coverage, thereby significantly enhancing the oxygen evolution reaction (OER) activity for seawater electrolysis. Notably, the representative Sn–CoOOH–PO43– catalyst demonstrates satisfactory catalytic performance and durability, achieving a long-term stability of 1000 h at 750 mA cm–2 (1.78 V) in simulated seawater electrolysis and 500 h at 500 mA cm–2 (2.05 V) in alkaline natural seawater electrolysis.