Anionic regulation Fe/NiOOH electrocatalysts to boost electrooxidation performance of biomass derived 5-hydroxymethylfurfural.

Nickel-based catalysts show great potential as promising candidates for the electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF). However, the limited adsorption capacity of nickel-based catalysts for OH and HMF limits their further development. In this study, amorphous Fe/NiOOH-SO was generated from nanosheets (Fe/NiOOH-NiS), which was pre-fabricated on nickel foam via pre-reconstruction and anionic regulation strategy. The optimized catalyst Fe/NiOOH-NiS demonstrated exceptional activity in the HMF oxidation reaction (HMFOR) with a current density of 10 mA cm at 1.32 V vs RHE, accompanying with the 98.9 % HMF conversion, 97.8 % 2,5-Furandicarboxylic acid (FDCA) selectivity, 96.8 % Faraday efficiency, and stability for ten cycles. The incorporating amorphous FeOOH reduces the electron density around Ni, promoting the formation of high-valent Ni spices. Meanwhile, the SO combined with amorphous hydroxy nickel oxide provides unsaturated sites, which enhances the adsorption capacity of HMF. Density functional theory (DFT) computations reveal that the designed amorphous Fe/NiOOH and surface-adsorbed SO collectively modulate the electronic structure of the catalyst, causing an upwards shift of the NiOOH d-band center and enhancing adsorption capacities for both HMF and OH. This study proposes the adsorption enhancement mechanism of regulating electronic structure and offers a rational strategy for HMFOR electrocatalysts.