Decoupling adsorption of substrate and hydroxide via defect-modified CoFe-layered double hydroxide for enhanced 5-hydroxymethylfurfural electrooxidation.

The electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a pivotal route for biomass valorization but faces dual challenges: weak HMF adsorption and severe competitive adsorption with OH-. Herein, we report a MoOx-decorated defective CoFe-layered double hydroxide (MoOx-Ov-LDH) fabricated via a defect-creation-defect-filling strategy. This design integrates complementary functions: oxygen vacancies enhance HMF adsorption, while the MoOx decoration process further proliferates defect sites to strengthen HMF binding and simultaneously provides Lewis acid sites for preferential OH- adsorption. This creates spatially segregated adsorption sites for HMF and OH-, effectively mitigating competitive adsorption. Consequently, MoOx-Ov-LDH delivers outstanding performance: a low potential of 1.38 V at 50 mA cm-2 and a 95.0 ± 1.7% FDCA yield in a three-electrode system, and under simulated industrial flow electrolysis, achieves 93.7 ± 2.2% FDCA yield with 90.4 ± 2.1% Faradaic efficiency and stable operation over twelve cycles. This work establishes a site proliferation and function separation paradigm for rationally designing electrocatalysts for complex reaction networks in biomass conversion.