Benzenetricarboxylic Acid Ligand Modification and Cr-Leaching Synergy in Multimetal Cobalt Hydroxide for Efficient HMF Electrooxidation

Replacing the energy-intensive oxygen evolution reaction (OER) at the anode of water electrolysis with the electrooxidation of biomass-derived small molecules is an appealing route to energy-saving hydrogen production. The key challenge remains the development of catalysts that are both highly active and durable. Here, we reported a ternary Ni–Co–Cr hydroxide electrode modified by 1,3,5-benzenetricarboxylic acid (BTC), denoted NiCoCr-BTC, for the anodic 5-hydroxymethylfurfural oxidation reaction (HMFOR) coupled to hydrogen production. Activated NiCoCr-BTC delivered an onset potential of 1.28 VRHE and a current density of 166.38 mA cm–2 at 1.50 VRHE. In multicycle durability tests, the Faradaic efficiency (FE) and product selectivity toward 2,5-furandicarboxylic acid (FDCA) both exceed 97%, with excellent stability. In situ spectroscopic characterization revealed a synergistic effect between surface-modified BTC and dynamically leached Cr species that promoted the operando formation of higher-valent Co active sites and enhanced OH– enrichment, endowing HMFOR with more favorable kinetics than OER. This work provided a viable strategy to design biomass-assisted hydrogen-production catalysts that combine high activity, selectivity, and stability.