Synergistic SiO2@NC core-shell nanosphere enhances catalytic hydrogenation of lignin-derived aromatic aldehydes

Abstract

The design of heterogeneous catalysts to enhance substrate adsorption and hydrogen spillover plays a key role in the hydrogenation of biomass-derived chemicals. Herein, a composite catalyst support featuring a nano-SiO2 core and a nitrogen-doped carbon shell was developed for Pd loading (Pd/SiO2@NC). Following NC coating, the pyridine-N and pyrrole-N in the porous NC shell interacted with Pd through their lone pair electrons, enabling the anchoring and dispersion of Pd nanoparticles. The incorporation of SiO2 with NC notably increased the electronegativity at the interface, improving the vanillin (VAN) adsorption through both VAN-Pd and VAN-SiO2@NC interactions. Moreover, electron transfer between SiO2 and NC promoted hydrogen spillover, effectively lowering the energy barrier for the hydrogenation process. Consequently, >99% of VAN was completely hydrogenated to vanillyl alcohol over Pd/SiO2@NC under mild conditions (0.5 MPa H2, 20 °C, 60 min). The catalyst exhibited widespread activity for various lignin-derived aromatic aldehydes, indicating considerable potential for industrial applications. This study constructed the active catalyst surface that successfully synthesized aromatic alcohols from renewable lignin-derived compounds, effectively replacing traditional synthesis process.