Regulating the microenvironment of catalytic sites by atomically precise and charge tunable Au₂₅ nanoclusters for efficient 5-hydroxymethylfurfural electro-oxidation

Electrochemical biomass oxidation has garnered considerable attention due to its low energy consumption and the production of high-value chemicals. Supported metal nanoparticle catalysts have been widely explored in electrochemical 2,5-hydro-xymethylfurfural oxidation reaction (HMFOR) but limited by their inhomogeneity to build a clear structure-ability relationship at atomic level. Atomically precise metal nanoclusters with well-defined composition, high purity and unique physichemical property are one kind of ideal model electrocatalyst. In this work, we regulate the microenvironment of catalytic sites in NiSe₂ utilizing atomically precise and charge tunnable Au₂₅ nanoclusters. The electrochemical results reveal that after the modification of Au₂₅ nanoclusters, the HMFOR ability of NiSe₂ could be enhanced. Among them, the NiSe₂ modified with Au₂₅⁻ clusters displayed the best electrocatalytic ability, in which the electrons were preferred to transfer from Au₂₅⁻ to NiSe₂ substrate resulting in the electrons accumulation at the electrocatalyst surface. The enhanced electrochemical performance of electrocatalyst can be attributed to two key factors: (1) enhanced adsorption ability towards HMF due to the strong interaction between electron enriched surface and electrophilic furan rings; (2) fast electron transfer at Au₂₅⁻/NiSe₂ interface, resulting in the rapid structure evolution to form active NiOOH sites. This study serves as a valuable reference for designing highly efficient, atomically precise metal nanocluster electrocatalysts for biomass upgrading.