Interfacial electron withdrawal by high-valence Mo6+ drives electron-deficient Ni sites for synergistic HMF electrooxidation

Modulating the electrocatalytic interface is key to efficiently converting 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA). Herein, a NiCo( OH ) x /NiCoMoO 4 heterojunction electrocatalyst is constructed. The high-valence Mo 6+ substrate acts as an electron regulator, creating electron-deficient Ni sites and promoting the formation of active Ni 3+ species for HMF oxidation. Operando analysis and distribution of relaxation times (DRT) studies confirm that the Mo 6+ substrate enhances charge transfer and mass transport. This special electronic structure directs selective aldehyde group activation, steering the reaction along the HMFCA pathway. The obtained catalyst achieves a 91.4% FDCA yield with 96% Faradaic efficiency at 1.4 V vs. RHE. This work demonstrates a dual modulation strategy via high oxidation state substrate for efficient biomass conversion.