One-Pot Synthesis of Stable Pd@mSiO2 Core–Shell Nanospheres and Their Application to the Hydrogenation of Levulinic Acid

The new catalyst Pd@mSiO2 was synthesized by a simple and gentle one-step process, mesoporous silica as the shell and metal particles as the core. The characterization showed that the catalyst structure was regular, the core–shell structure was clear, and each microsphere guarantees the existence of a single nucleus. The pore size and the thickness of mesoporous silica layer can be effectively adjusted by adjusting the molecular weight of template and the amount of silicon source. The Pd@mSiO2 was applied in the hydrogenation of levulinic acid to prepare γ-valerolactone, the conversion of levulinic acid was 95%, and the selectivity of γ-valerolactone was close to 96%. In addition, the catalyst had a good reuse performance compared to commercial catalysts. After repeated use for ten times, the catalytic activity did not decrease, which was mainly attributed to the fact that the core–shell structure can better protect the active metal particles and prevent the particles from agglomeration and loss at high temperature.