Low Concentration Template Preparation of Microsized Au/TS-1 as an Efficient Catalyst for Gas-Phase Propylene Epoxidation with H2 and O2

Micrometer-sized TS-1-L zeolite was synthesized in an ultralow molar ratio of TPAOH/SiO2 (0.05) using an aerosol-assisted hydrothermal synthesis method, and Au nanoparticles were deposited on the TS-1 zeolites to prepare the Au/TS-1-L catalyst for the direct epoxidation of propylene with H2 and O2. Interestingly, the micrometer-sized Au/TS-1-L exhibits better catalytic activity than the small-crystal Au/TS-1-S. The mass transfer capabilities of Au/TS-1-L and Au/TS-1-S do not show an obvious difference, because the formation of the hollow void structure may reduce the diffusion path of TS-1-L. Moreover, the higher amount of Ti3+ sites on TS-1-L, which can effectively promote the generation of the active Ti-OOH intermediate, is beneficial for catalytic performance. The easily separated micrometer-sized TS-1 may provide a potential application in low-temperature (160 °C) selective oxidation reactions.