Interfacial Carrier Engineering of NiO/MS2 Nanosheets for Electro-Oxidation of 5-Hydroxymethylfurfural with an Ampere-Level Current Density

Abstract

Understanding how the electronic environment regulates catalyst reconstruction is essential for advancing biomass electro-oxidation. Here, we design a series of model catalysts by anchoring NiO species on two-dimensional MS₂ nanosheets (M = Sn, Ta, Mo, Ti) to probe how the electronic properties of substrates influence catalytic performance. Substrates with a lower carrier concentration were found to induce stronger interfacial charge transfer from NiO, generating electron-deficient Ni centers that readily reconstruct into an active NiOOH phase. Spectroscopic analyses reveal elongated Ni–O bonds and elevated Ni valence, consistent with enhanced oxidation propensity. Consequently, the NiO/SnS₂ catalyst can be operated at an ampere-level current density at 1.45 V vs RHE, with 98.7% FDCA yield, 99% Faradaic efficiency, and robust cycling stability. Density functional theory calculations further show that interfacial charge redistribution lowers the adsorption barriers of HMF and *OH, accelerating the deprotonation step. This work offers insights into the rational design of high-performance biomass electro-oxidation catalysts.