High-Conductivity\nLignin-Derived Carbon Fiber-Embedded\nCuFe<sub>2</sub>O<sub>4</sub> Catalysts for Electrooxidation of HMF\ninto FDCA

The electrocatalytic oxidation of 5-hydroxymethylfurfural\n(HMF)\nprovides a viable pathway for the efficient utilization of biomass\nresources. However, designing and regulating the activity and selectivity\nof the corresponding electrocatalysts remain significant challenge.\nSpinel compounds show great potential as catalysts due to their adjustable\nelectronic structures and notable catalytic properties, but their\nintrinsic low conductivity has limited their further application.\nHerein, a lignin-based carbon fiber (LCF) embedded CuFe<sub>2</sub>O<sub>4</sub> catalyst (CuFe<sub>2</sub>O<sub>4</sub>/LCF) is successfully\nconstructed using an electrospinning technique. The catalyst can efficiently\nand selectively synthesize 2,5-furandicarboxylic acid (FDCA) at a\nrelatively low potential. The experimental results and theoretical\nsimulations demonstrate that the introduction of lignin can significantly\noptimize the pregraphitic turbine carbon microstructure of the carbon\nfibers and facilitate rapid electron transfer between CuFe<sub>2</sub>O<sub>4</sub> and the carbon layer. Furthermore, the A<sub>Td</sub>–O–B<sub>Oh</sub> interactions on the surface of the\nCuFe<sub>2</sub>O<sub>4</sub> spinel structure significantly enhance\nthe adsorption capacity for the substrates and OH<sup>–</sup> species, effectively promoting the catalytic reaction. The findings\nhope to provide a unique perspective to improve the catalytic activity\nof lignin carbon fiber spinel catalysts and the stability of biomass\nvalue-added mechanism.