Construction of X-CeO2/FeS heterointerfaces via halogen doping for accelerated oxygen evolution electrocatalysis

Designing and developing high-activity and long-term durability electrocatalysts for the oxygen evolution reaction (OER) has primary significance for breaking the bottleneck of water electrolysis. In this study, we synthesized a series of halogen-doped cerium–iron heterostructures with abundant oxygen vacancies on the surface of nickel foam using a simple hydrothermal method. In this structure, the conversion between Ce 3+ and Ce 4+ in CeO 2 generates abundant oxygen vacancies that effectively enhance catalyst activity. Concurrently, the combination of the heterostructure and anion doping design synergistically lowers the reaction energy barrier to boost catalytic activity, enabling robust kinetics for the OER reaction. Electrochemical tests demonstrated that the Br-CeO 2 /FeS-NF catalyst exhibited excellent OER performance in 1.0 M KOH solution, with an overpotential of only 204 mV at a current density of 10 mA·cm -2 and a Tafel slope of 31.6 mV·dec ‑1 . Meanwhile, the catalyst exhibited good long-term stability in alkaline electrolyte, with an operational stability of 72 h at 100 mA·cm -2 .