Chloride-Repellent Water Layer Enabled by Ce Single Atoms for Poison-Resistant Seawater Electrolysis

Abstract

Seawater electrolysis offers a promising avenue for green hydrogen production in regions rich in renewable energy sources but scarce in freshwater. However, the severe poisoning and corrosion of catalysts by chloride ions (Cl–) remain a formidable obstacle. Herein, we report a cerium single-atom-doped cobalt phosphide nanowire catalyst (Ce1/CoP) that exhibits exceptional activity and unprecedented resistance to Cl– for the hydrogen evolution reaction (HER). In an alkaline electrolyte, the overpotential of Ce1/CoP at 10 and 100 mA cm–2 remains virtually unaffected (fluctuation < 5 mV) across the entire range of NaCl concentrations from 0 M to saturation, whereas that of undoped CoP increases by over 20 mV. Density functional theory calculations reveal that introducing Ce lowers the d-band center of the Co site and optimizes the Gibbs free energy of hydrogen adsorption on Ce1/CoP, thereby accelerating the H2 generation kinetics. Molecular dynamics simulations and electrostatic potential analysis reveal that the superior Cl– resistance originates from effective repulsion of Cl– on the Ce1/CoP surface, forming a protective water layer that shields the catalyst from Cl– poisoning and corrosion. This work provides new insights into the design of advanced catalysts with excellent Cl– tolerance and stability for seawater splitting.