Interfacial Dipole Engineering of Single-Atom Co-N-C and Ru Nanoparticles for Enhanced Hydrogenation of Levulinic Acid to γ-Valerolactone.

The catalytic hydrogenation of levulinic acid (LA) constitutes the central pathway for its conversion into high-value γ-valerolactone (GVL); however, the prevailing challenge lies in enhancing its catalytic activity and stability under mild conditions. Herein, an interfacial dipole effect was established when single-atom Co1-N-C was used as a support to anchor Ru nanoparticles (RuNPs/Co1-N-C), which led to the transfer of electrons from Co1-N-C to Ru nanoparticles and maintenance of electron-rich Ru. The RuNPs/Co1-N-C catalyst exhibits enhanced catalytic performance in LA hydrogenation, achieving nearly complete conversion and 100% selectivity toward GVL under ambient conditions. The RuNPs/Co1-N-C catalyst maintained its catalytic activity and selectivity over 10 consecutive cycles without noticeable deactivation, and the other 5 biomass-derived compounds could also be effectively converted into corresponding lactone compounds. Density functional theory calculations reveal that the interfacial dipole effect of RuNPs/Co1-N-C lowers the barriers of key kinetically relevant steps, particularly enabling near-zero-barrier H2 dissociation while lowering the activation barriers for subsequent hydrogenation and final dehydration steps. Therefore, through interfacial dipole engineering between the single-atom support and nanoparticles, the electronic structure of the metal sites can be adjusted, thereby enhancing the activity and stability of the catalyst in biomass upgrading and hydrogenation reactions.