P‐Doped NiS for Low‐Potential Electrooxidation of 5‐Hydroxymethylfurfural to 2,5‐Furandicarboxylic Acid

ABSTRACT Efficient electrochemical upgrading of biomass‐derived feedstocks to value‐added chemicals is an attractive route toward sustainable chemical manufacturing. The anodic oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) is often hindered by sluggish substrate adsorption/activation and competing oxygen evolution, calling for catalysts that deliver high selectivity at low potentials. Here, we report phosphorus‐doped NiS nanoelectrocatalysts (P‐NiS) synthesized via a microwave‐assisted deep eutectic solvent (DES) hydrothermal process followed by phosphidation. The optimized P‐NiS catalyst achieves 99.2% HMF conversion, 98.5% FDCA yield, and 97.7% Faradaic efficiency at 1.32 V. Density functional theory calculations indicate that P doping modulates the electronic structure of NiS and strengthens the HMF‐surface interaction, accounting for the enhanced HMFOR activity. This work provides an effective non‐noble‐metal catalyst and a robust design strategy for selective HMF electrooxidation to FDCA.