Ligand-Hybridization Activates Lattice-Hydroxyl-Groups of NiCo(OH)_x Nanowires for Efficient Electrosynthesis

Electrochemical dehydrogenation of hydroxides plays a crucial role in the formation of high-valence metal active sites toward 5-hydroxymethylfurfural oxidation reaction (HMFOR) to produce the value-added chemical of 2,5-furandicarboxylic (FDCA). Herein, we construct benzoic acid ligand-hybridized NiCo(OH)_x nanowires (BZ-NiCo(OH)_x) with ample electron-deficient Ni/Co sites for HMFOR. The robust electron-withdrawing capability of benzoic acid ligands in BZ-NiCo(OH)_x speeds up the electrochemical activation and dehydrogenation of lattice-hydroxyl-groups (M²⁺-O-H⇌M³⁺-O), boosting the formation of abundant electron-deficient and high-valence Ni/Co sites. DFT calculation reveals that the deintercalation proton is prone to establishing a hydrogen bridge with the carbonyl group in benzoic acid, facilitating the proton transfer. Coupled with the synergistic oxidation of Ni/Co sites on hydroxyl and aldehyde groups, BZ-NiCo(OH)_x delivers a remarkable current density of 111.20 mA cm^-2 at 1.4 V for HMFOR, exceeding that of NiCo(OH)_x by approximately fourfold. And the FDCA yield and Faraday efficiency are as high as 95.24 % and 95.39 %, respectively. The ligand-hybridized strategy in this work introduces a novel perspective for designing high-performance transition metal-based electrocatalysts for biomass conversion.