Enhancing electrocatalytic oxidation of 5-hydroxymethylfurfural via Ce(4f)–O(2p)–TM(3d) orbital coupling to modulate reactant adsorption equilibrium

Transition metal oxyhydroxides are crucial for the electrochemical oxidation of 5-hydroxymethylfurfural (HMF), though the co-adsorption and activation mechanisms of HMF and hydroxyl species require further clarification. This study designs cerium-doped Co-based layered double hydroxide (LDH) arrays, including 3%Ce-Co 3 Fe 1− x Al x -LDH/NF, to investigate Fe as a secondary active center and the role of Ce–O–TM (Transition metal) bridges in regulating HMF/OH − adsorption. Theoretical calculations indicate that Ce–O–TM bridges induce f – p – d gradient orbital coupling, optimizing HMF/OH − adsorption configurations and facilitating the HMF oxidation reaction (HMFOR). Synchrotron radiation characterization and in situ Raman spectroscopy reveal that Fe enhances electronic interaction between Ce and Co/Fe sites, strengthening the stability of M–O bonds, suppressing metal dissolution, and further optimizing reactant adsorption. Fe doping also modulates charge distribution and accelerates charge transfer. The optimized 3%Ce-Co 3 Fe 1 -LDH/NF delivers industrial current density (0.1 A cm −2 ) at 1.44 V RHE , with 98.1% HMF conversion, 99.6% FDCA yield, and 99.8% Faradaic efficiency. In an anion exchange membrane (AEM) electrolyzer, it achieves 0.5 A cm −2 at 2.1 V while maintaining high stability across 0.1–0.5 A cm −2 . These results provide an effective strategy for designing high-performance HMFOR catalysts through electronic structure modulation.