In Situ Growth of Thin‐Layer Nanosheet Arrays of Cu‐Doping NiO for Enhanced Adsorption and Electrooxidation of Biomass

Abstract With the accelerating depletion of fossil fuels, biomass energy has garnered significant attention as a promising renewable energy source. The electrocatalytic conversion of biomass into high‐value‐added products holds substantial research significance. In this study, the catalyst structure is systematically optimized by fine‐tuning the ratio of adjacent transition metals, nickel (Ni) and copper (Cu), leading to the design of an ultrathin‐layered nanosheet array catalyst, Cu _1/8 ‐NiO@NF. This catalyst exhibits exceptional performance in the electrocatalytic oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA). The catalyst shows excellent stability over 40 HMF oxidation reaction (HMFOR) cycles at a relatively low electrolysis potential of 1.45 V (vs RHE). In a single cycle, the catalyst achieves complete conversion of HMF with 99.5% FDCA yield, 99.6% Faraday efficiency (FE), and nearly complete HMF conversion. A series of electrochemical tests reveals that the incorporation of Cu not only accelerates the formation of NiOOH reactive intermediates but also enhances the charge transfer process. Density Functional Theory (DFT) calculations indicate that local substitution of Cu improved HMF adsorption and lowered the reaction energy barrier. This study provides a facile approach for developing efficient electrocatalysts for HMF oxidation.