Core–Shell Structured Zeolite Catalysts with Enhanced Shape Selectivity

Zeolites have uniform micropores and shape selectivity works in their uniform micropores. Catalytic active sites located in the uniform micropores can enable shape-selective reactions. However, some active sites are often present on the external surface of zeolites, where shape selectivity does not work, leading to a decrease in selectivity. Herein, we introduce three types of core-shell structured zeolite catalysts with enhanced shape selectivity: (1) Core-shell ZSM-5/silicalite-1 catalyst for shape-selective production of aromatics from C1-3 feedstocks, (2) Zn ion-doped core–shell ZSM-5/silicalite-1 catalyst for enhanced production of p-xylene from methanol, and (3) Pt nanoparticle catalyst encapsulated in silicalite-1 for shape-selective hydrogenation. These core-shell structured zeolite catalysts have inert shell layers of silicalite-1 zeolite. All active sites are covered with inert shell layers of silicalite-1 zeolite, which can maximize the shape selectivity of zeolites.