Highly efficient hydrogenation of levulinic acid into γ-valerolactone over modified bifunctional yolk-shell catalyst

Abstract γ-valerolactone (GVL) is a widely used chemical raw material, which is mainly prepared by hydrogenation of levulinic acid (LA). The steps of hydrogenation and molecular lactone cyclization in the reaction make it require multi-active site catalysis. In this study, the Pd@mSiO 2 -CeAl catalyst was successfully prepared by doping Ce and Al to modify the Pd-based yolk-shell catalyst. It was used to catalyze LA to prepare GVL. In circumstances of mild response, 100% LA conversion and 97.5% GVL selectivity were obtained. The characterization results showed that the synergistic effect of the double acid sites (Brønsted and Lewis acid sites) and the hydrogenation sites is the key to high catalytic performance. Besides, the encapsulation strategy of the silica shell provides a stable catalytic environment for the catalyst and maintains high activity after 5 cycles.