Using natural resources to construct electrocatalysts for biomass conversion and elucidating their catalytic mechanisms are of great significance, but have remained challenging. Here, a series of 2D biomass-based Pb/PbO@C catalysts with Pb/PbO nanoparticles anchored on carbon nanosheets were synthesized using natural-derived humate as the precursor. By adjusting the carbonization temperature, an electron-deficient Pb⁰/Pb²⁺ dual-center-site catalyst can be achieved. The optimized Pb/PbO@C catalyst showed an excellent performance for the electrochemical hydrogenation of 5-hydroxymethylfurfural (HMF) to high value-added 2,5-bis(hydroxymethyl)furan (BHMF), with high faradaic efficiency (FE: 91.9%) and selectivity (Sel: 89.7%), achieving comparable performance to those of the reported noble metal-based electrocatalysts. Mechanism study revealed that the electron-deficient Pb⁰/Pb²⁺ dual-center-site provided abundant Lewis acidic sites and promoted the dissociation of water to the active hydrogen (H*) species, thus enhancing the adsorption of HMF on Pb²⁺ sites and the coverage of H* species on Pb⁰ sites. The high coverage of H* species and the synergistic effect of dual-center sites substantially promoted the binding of H* and HMF to form H-HMF* and inhibited the recombination of H* species, thereby accelerating the reaction kinetics of HMF reduction.

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.