Sustaining Electrooxidation of Concentrated Thermo‐Sensitive Biomass Feedstocks by Temperature‐Mediated Kinetic and Interfacial Control

Abstract

Abstract The inherent thermo‐sensitivity of biomass feedstocks often leads to side reactions (e.g., condensation) during biomass upgrading. Electrooxidation of biomass feedstocks offers a sustainable and mild route for synthesis of value‐added chemicals. However, non‐Faradaic side reactions still occur in alkaline electrolytes, which severely compromise product selectivity and operational stability at high feedstock concentrations, remaining a critical obstacle for practical implementation. Herein, we propose a temperature optimization strategy for efficient and stable electrooxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) on a designed superhydrophilic nickel‐based catalyst. Especially, at 10 °C the yield and Faradaic efficiency of FDCA exceeded 94% at a high HMF concentration of 1.6 M (20 wt.%), accompanied by stable performances for at least 480 h under industrially relevant current densities. Conversely, electrocatalytic performances degraded rapidly over time at 25 °C. Lowering temperature prevents electrode fouling by inhibiting non‐Faradaic side reactions, thus preserving catalytic site accessibility. Furthermore, the adsorption of OH − , identified as the rate‐determining step, is promoted by reducing temperature in the adsorptive competition with HMF, sustaining efficient β ‐Ni(OH) 2 / β ‐NiOOH redox cycle with elevated HMF concentrations. The stabilization and optimization of interfacial microenvironment enable durable and efficient electrooxidation of HMF and other thermo‐sensitive biomass derivatives to desired organic acids.