Unraveling the Potential‐Regulated Selectivity of the Cu‐Based Catalyst in 5‐Hydroxymethylfurfural Electro‐Oxidation

Abstract 2,5‐Furandicarboxylic acid (FDCA), prepared via the 5‐hydroxymethylfurfural electro‐oxidation reaction (HMFOR), is a promising bio‐based plastic monomer for biodegradable polymer production. However, the sluggish hydroxyl oxidation kinetics inhibit the HMFOR efficiency. In this study, CuO x H y is grown on Cu foam as a model electrocatalyst to investigate the active phases of the Cu‐based catalyst in the HMFOR, elucidate their oxidation mechanisms and adsorption behaviors at varying potentials, and ultimately to reveal the potential‐regulated selectivity of the Cu‐based catalyst. Experimental and theoretical studies reveal that Cu III ─OOH, generated from CuO at high potentials, exhibits enhanced catalytic activity, enabling HMFOR to proceed via an indirect oxidation process that favors aldehyde oxidation. A further increase in potential activates the direct oxidation process of Cu III ─OOH, selectively oxidizing hydroxyl groups owing to the increased substrate coverage on the catalyst, which hinders aldehyde adsorption. This study offers a new strategy for enhancing the selectivity towards the oxidation of specific functional groups in value‐added biomass conversion processes.