Catalytic electrochemical oxidation of a bio-model, 5-hydroxymethyl furfural, toward a circular plastic economy

Electrochemical oxidation has emerged as a pivotal green technology for synthesizing 2,5-furandicarboxylic acid (FDCA). As a bio-based platform molecule prioritized by the U.S. Department of Energy, FDCA serves as a sustainable alternative to petroleum-derived terephthalic acid, facilitating the transition toward a circular plastic economy. Traditional oxidation of 5-hydroxymethylfurfural (HMF) relies on high-temperature and high-pressure conditions, resulting in significant energy consumption and environmental drawbacks. In contrast, electrochemical oxidation enables efficient conversion of hydroxymethyl and aldehyde groups to carboxyl groups through a six-electron transfer process, making it a rapidly growing research focus. This review systematically examines key advancements in the field. It distinguishes between direct and indirect oxidation pathways: direct oxidation maintains stable catalyst valence states, while indirect oxidation employs redox mediators for electron transfer. The regulatory mechanisms of electrolyte pH, composition, and substrate concentration on product selectivity are elucidated. Strategies for modulating catalytic performance are proposed, including active metal type, size, support, and coordination environment optimization. Combined with defect engineering, strain regulation, and doping techniques, these approaches significantly enhance catalytic efficiency and FDCA selectivity. Furthermore, pairing this process with hydrogen evolution or CO₂ reduction reactions reduces electrolysis voltage and improves energy conversion efficiency. Through life cycle assessment, the article analyzes techno-economic viability and environmental benefits. Critical challenges for industrialization are identified, including suppressing non-Faradaic biomass degradation under alkaline conditions and developing efficient reactors. Finally, the importance of interdisciplinary collaboration is emphasized. Future efforts should prioritize advanced catalyst design, precise reaction condition control, and process scale-up optimization to bridge the gap between laboratory research and industrial production.