The state-of-the-art synthetic strategies for SAPO-34 zeolite catalysts in methanol-to-olefin conversion

Methanol-to-olefin (MTO) conversion has proven to be one of the most successful non-petrochemical routes for producing light olefins. Silicoaluminophosphate (SAPO) zeolite SAPO-34 is one of the best industrial catalysts for MTO conversion, but suffers from rapid deactivation due to the inherent diffusion bottleneck limited by the narrow eight-ring pore openings. To improve the MTO performance, considerable synthetic efforts have been devoted to decrease the crystal size of zeolites or introduce secondary larger pores in zeolite crystals to form hierarchical structures. This review mainly focuses on presenting the state-of-the-art synthetic strategies for nanosized and hierarchical SAPO-34 catalysts with excellent MTO performance. Furthermore, the industrialization of SAPO-34 catalysts for the MTO reaction, and some current problems and future prospects for the synthesis of SAPO-34 catalysts, are also pointed out. We expect that this review can not only shed some light on the preparation of SAPO-34 catalysts, but also stimulate the future development of high-performance SAPO-34 catalysts to meet the increasing demands of the chemical industry.