Unlocking Thermodynamic‐Kinetic Synergy via Rh/Co Dual Sites and Ordered Interfacial Hydrogen‐Bond Network for Efficient Biomass Electrooxidation

ABSTRACT Electrocatalytic oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) offers a sustainable route to bio‐based polymer monomers, yet its efficiency is constrained by sluggish adsorption and proton‐coupled electron transfer (PCET) kinetics. Herein, we report a composite catalyst comprising amorphous RhO _x anchored on cobalt‐deficient Co ₃ O ₄ (RhO _x ‐Vco) that synergistically optimizes both thermodynamics and kinetics. Combined experiments and theoretical calculations unveil that RhO _x and Co defects collaboratively upshift the d‐band center of Co and create Rh/Co dual sites, cooperatively enhancing HMF and OH ⁻ adsorption. Concurrently, this strengthened OH ⁻ adsorption guides preferential parallel alignment of interfacial water molecules, fostering a highly connected hydrogen‐bond network that accelerates PCET kinetics. Benefiting from this multi‐level synergy, RhO _x ‐Vco achieves a seven‐fold higher current density at 1.40 V than pristine Co ₃ O ₄ , along with a high FDCA yield of 95.8% in three‐electrode system. Remarkably, when integrated into a membrane electrode assembly flow electrolyzer, the system maintains excellent performance with 93.4% FDCA yield, 85.6% Faradaic efficiency, and robust cycling stability, demonstrating its practical viability. This work establishes a design paradigm integrating defect and interface engineering to coordinately regulate multi‐step reaction processes, offering broad insights for advancing biomass and PCET‐related electrocatalysis.