Preparation, structure and performance of TS-1 zeolite-coated Au-Pd/TiO2-SiO2 capsule catalyst for propylene epoxidation with oxygen and hydrogen

A compact zeolite membrane of TS-1 was crystallized on the surface of Au-Pd/TiO2-SiO2 catalyst pellets by a hydrothermal synthesis method. The synthesized capsule catalyst has a core-shell structure without pinholes and cracks. For the reaction of propylene epoxidation using oxygen and hydrogen, the synthesized capsule catalyst shows much higher propylene conversion and PO yield than those of the conventional physically mixed catalyst with the same composition. The core-shell capsule catalyst provides a tailor-made confined reaction environment, which can be extended to various consecutive reactions as the shell and core components are independent catalysts of different reactions.