Supported noble metal catalyst with a core-shell structure for enhancing hydrogenation performance

Abstract

• An efficient Pd/S-1@ZSM-5 core-shell catalyst was prepared. • The strong acid sites around metal NPs can be regulated by controlling the coverage of nano-ZSM-5 shell. • Rational structure of Pd/S-1@ZSM-5 is beneficial for diffusion of bulky reactants. • Pd/S-1@ZSM-5 catalyst exhibits stronger naphthalene hydrogenation capacity. • Pd/S-1@ZSM-5 catalyst shows good sulfur-tolerance. Supported noble metal nanoparticles are a kind of high efficiency of catalysts in aromatics hydrogenation, and the properties and structures of supports are of great importance to improve hydrogenation behaviors. In this work, an efficient Pd/S-1@ZSM-5 core-shell catalyst with an enhanced naphthalene hydrogenation ability was prepared by building acidic nano-ZSM-5 shells surrounding silicalite-1 supported Pd NPs. The acidic nano-ZSM-5 shell can strengthen the spillover hydrogenation due to the increase of the strong acid sites around Pd NPs, and the strong acid sites around metal NPs can be regulated by controlling the coverage of nano-ZSM-5 shell. Additionally, the formed mesoporous structure of nano-ZSM-5 shell is beneficial for the diffusion of bulky reactants. These are the two important factors for enhancing hydrogenation ability of Pd/S-1@ZSM-5 catalyst. Furthermore, Pd/S-1@ZSM-5 catalyst also shows good sulfur-tolerance in the presence of thionaphthene. This work presents an elegant example for enhancing hydrogenation abilities of noble metal catalysts by constructing a core-shell structure.