Electronic structure modulation in Co-doped NiFe-LDH for efficient ethylene glycol oxidation in simulated seawater

Polyethylene terephthalate (PET) waste presents a major environmental burden, yet it can serve as a feedstock for value-added chemicals. Here, we report cobalt-doped nickel–iron layered double hydroxides (Co/NiFe-LDH) with tunable Co contents, prepared by a one-step solvothermal route, as efficient electrocatalysts for the ethylene glycol oxidation reaction (EGOR) in simulated seawater (SW). Among the series, 0.35Co/NiFe-LDH delivers the highest activity, reaching 87.7 mA cm −2 at 1.60 V vs. reversible hydrogen electrode (RHE) in simulated SW containing 1 M ethylene glycol (EG), together with a formate faradaic efficiency of 93.8% at 1.60 V. The catalyst also shows strong durability and chloride tolerance, retaining 50.3 mA cm −2 after 6 h of operation and exhibiting robust Cl − resistance. Density functional theory calculations indicate that Co incorporation shifts the d-band center toward the Fermi level, strengthens EG adsorption, and lowers the energy barrier of the rate-determining step of the desorption of HCOOH* intermediate, thereby accelerating EGOR kinetics. Notably, the catalyst performs effectively in PET upcycling scenarios by catalyzing EGOR directly in PET hydrolysis products. This work offers a practical strategy to design high-performance, non-precious-metal EGOR catalysts operable in simulated seawater, supporting sustainable plastic waste valorization while reducing freshwater demand.