Preparation and modification of Au/TS-1 catalyst in the direct epoxidation of propylene with H2 and O2

• The low-coordinated Au atoms favor the migration of H 2 O 2 to adjacent framework Ti sites in time. • In deposition-precipitation (DP) process, the charge matching of TS-1′s surface with Au slurry solution at pH of 7 is advantage to Au loading. • Hierarchical TS-1 zeolites with small crystal size and blocked TS-1 zeolites were developed to improve the diffusion of reactants and products, avoiding catalyst in deactivation. • Au/TS-1 pretreated in H 2 -containing instead of O 2 -containing atmosphere shows great catalytic property for epoxidation reaction. The gas-phase epoxidation of propylene with H 2 and O 2 has been explored by a number of researchers due to its green nature. It is an environmentally more benign and more efficient alternative to existing industry processes, such as the chlorohydrin method and hydroperoxide process. As the catalyst for this reaction, Au/TS-1 plays a critical role. In this review, we aimed to disclose the correlation between Au/TS-1′s catalytic property and the synthesis/modification strategies. Reaction mechanism was firstly summarized involving the generation of hydrogen peroxide (H 2 O 2 ) catalyzed by Au particles and epoxidation reaction catalyzed by TS-1 zeolites. Subsequently, the effects of different Ti species, Au particle size, loading position and chemical state on catalytic performance were discussed. Based on this, the modified strategies of TS-1 surface property and pore structure, synthesis methods for obtaining small and highly dispersed Au particles in deposition-precipitation (DP) process were emphasized. Pretreatment of Au/TS-1 catalyst to diminish hydroxyl defects and make it active in specific atmosphere were also demonstrated.