Insight into the mechanism of 5-hydroxymethylfurfural electroreduction to 2,5-bis(hydroxymethyl)furan over Cu anchored N-doped carbon nanosheets

Design of non-noble metal electrocatalysts for biomass conversion to high-value chemicals and understanding the related catalytic mechanisms are of profound significance but have remained a major challenge.Here,we developed a novel biomass-derived electrocatalyst(denoted as Cu/NC),featuring with electron-deficient copper nanoparticles anchored on N-doped carbon nanosheets,for the electrochemical reduction of 5-hydroxymethylfurfural(HMF)to 2,5-bis(hydroxymethyl)furan(BHMF,a vital precursor of functional polymers).The optimized Cu/NC electrocatalyst exhibited an excellent performance with high Faradaic efficiency(89.5%)and selectivity(90.8%)of BHMF at a low concentration of HMF(18.1 mM).Even at a very high HMF concentration(108.6 mM),the Faraday efficiency and selectivity of BHMF could still reach 74.8%and 81.1%,respectively.This performance approached those of the reported noble metal-based electrocatalysts.Mechanism study revealed that the N doping in the Cu/NC catalyst could regulate the electronic structure of Cu,strengthening the adsorption of the HMF carbonyl group,and thus boosting the selectivity of BHMF.Additionally,strong electronic metal-support interactions of Cu and the N-doped carbon support optimized the charge transfer rate,thus promoting the dissociation of water to the active hydrogen(H^(*))species and boosting the reaction kinetic rate of H^(*)and HMF.