Hydrogen‐Bond‐Assisted Electrocatalytic Semi‐Oxidation of 5‐Hydroxymethylfurfural into 2,5‐Diformylfuran by Operando Dissociated <i>N</i> ‐Oxyl Mediator

The conversion of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) is a promising approach for enhancing biomass utilization. Nevertheless, traditional methods using noble metal catalysts face challenges due to high costs and poor selectivity towards DFF. Herein, we developed a novel catalytic electrode integrating N-hydroxyphthalimide (NHPI) into a metal-organic framework on a hydrophilic carbon cloth. This design significantly enhances the selective adsorption of HMF due to stronger hydrogen-bond interaction between the electrode's hydrophilic surface and the C(sp³)-OH group in HMF compared to the C(sp²)=O in DFF. Additionally, the electro-driven dissociation of the NHPI-linker generates stabilized N-Oxyl radicals that promote selective semi-oxidation of HMF under neutral conditions. As a result, this approach achieves a high yield rate of 138.2 mol mol_cat ^-1 h^-1 with a selectivity of 96.7 % for the HMF-to-DFF conversion. This work introduces a novel strategy for designing catalytic electrodes with stabilized N-Oxyl radicals, and offers a promising method for electrocatalytic DFF synthesis, leveraging hydrogen-bond interaction between electrode surface and HMF.