Cerium-containing and oxalate anion Co-modified NiFe-layered double hydroxide promotes oxygen evolution reaction

NiFe-layered double hydroxides (LDH) exhibit excellent oxygen evolution reaction (OER) activity after doping and modification treatments, but their stability under high current densities is considerably limited. The rare-earth element cerium (Ce), owing to its variable valence states, can enhance structural stability by inducing lattice distortion and dynamic redox cycling when incorporated as a dopant. Meanwhile, oxalate ions (OA²⁻), with their larger spatial volume and more uncoordinated carboxylic acid groups (-COOH), act as proton transfer carriers. The synergistic effect between Ce and OA accelerates the OER kinetics of CeNiFe-LDH-OA@NF. The CeNiFe-LDH-OA@NF electrode demonstrates overpotentials of only 242 mV and 256 mV at high current densities of 100 mA cm⁻² and 200 mA cm⁻², respectively. Moreover, it exhibits exceptional stability under high current conditions, showing almost no decay in overpotential after continuous operation for 140 h at 100 mA cm⁻², with a minimal degradation rate of 0.5%. As a proton transfer carrier, the oxalate anion significantly enhances OER kinetics by optimizing the proton conduction pathway at the electrocatalytic interface. In cyclic voltammetry (CV) measurements, a negative shift and an increased slope of the characteristic reduction peak were observed, confirming that OA modification effectively regulates the hydroxyl adsorption energy barrier. The CeNiFe-LDH-OA@NF electrode demonstrates higher surface hydroxyl affinity.