Carbon-Driven Interfacial Molecular Enrichment Strategy for Efficient Electrooxidation of 5-Hydroxymethylfurfural

The electrochemical oxidation of HMF to FDCA represents an attractive strategy for biomass valorization. However, sluggish reaction kinetics caused by insufficient adsorption and activation of HMF molecules at catalyst interfaces remains a major challenge. Herein, we report a PdNiO/C composite catalyst in which Pd nanoparticles and NiO are integrated on a conductive carbon matrix for efficient HMF electrooxidation. The PdNiO/C catalyst exhibits a low onset potential (1.10 V vs. RHE) and achieves high FDCA yield and FE (>90%) with excellent electrochemical stability. Mechanistic investigations reveal that the carbon matrix induces an interfacial molecular enrichment effect through π-π interactions, which significantly increases the local concentration of HMF molecules near catalytic sites. Meanwhile, Pd facilitates the oxidation of Ni²⁺ to NiOOH active species and accelerates electron transfer. This work highlights an interfacial molecular enrichment strategy for improving biomass electrooxidation and provides new insights into the design of high-performance electrocatalysts for sustainable biomass upgrading.