Synthesis of a ZSM-5(core)/SAPO-5(shell) composite and its application in FCC

A core/shell structure composite was synthesized via a new method of pre-coating one raw material. The composite was characterized by X-ray diffraction, SEM, TEM and N-2 isothermal adsorption-desorption and Py-FTIR. In addition, the catalytic performance of the composite in cracking of heavy oil for producing olefin was also investigated. The characterization results show that the composite with a core/shell structure had smaller particle size, uniform SAPO-5 shell, and fewer acid sites than ZSM-5, accelerating the transport of reactant and product molecules between different zeolites. Consequently, the light olefins on the composites had high specific selectivity.