SDS-intercalated CoFe-LDH/FeOOH heterostructures: dual structural–electronic tailoring for efficient oxygen evolution reaction

Abstract An efficient sodium dodecanesulfonate (SDS)-intercalated CoFe-layered double hydroxide (LDH)/FeOOH electrocatalyst with a hierarchical structure was synthesized through a facile hydrothermal method for enhanced seawater oxidation. The intercalation of SDS expanded the interlayer spacing of LDHs markedly from 0.78 to 3.2 nm, optimizing mass transport channels and increasing reactive adsorption space. Geometric phase analysis revealed that the resulting lattice strain field exhibited disordered characteristics, which disrupted the symmetry of the original Co–O–Fe bonds and regulated the electronic structure of active sites through local lattice distortion. The proportion of defective oxygen increased from 69% to 84% after intercalation, providing abundant active sites for adsorbing critical intermediates (*OOH). Additionally, SDS acted as a surfactant, reducing the thickness of LDH nanosheets and exposing more edge-active sites. Electrocatalytic oxygen evolution reaction (OER) tests demonstrated that the SDS-intercalated CoFe-LDH/FeOOH achieved an overpotential of 290 mV at 10 mA cm−2, markedly lower than that of the nonintercalated sample (400 mV). Furthermore, no significant current density decay was observed during a 50-h stability test in natural seawater + 1 M KOH electrolyte.