Rapid preparation of SAPO-34/ZSM-5 composite molecular sieves modified by Cu–Ce and study on its catalytic performance of MTO

Abstract

The Cu–Ce modified SAPO-34/ZSM-5 (S-Z) composite molecular sieve catalysts were synthesized via a stepwise crystallization process using triethylamine (TEA) and tetraethylammonium hydroxide (TEAOH) as dual templates. This method significantly reduces the crystallization time from 24 h to 12 h. The incorporation of metal ions alters the structure and acid strength of the molecular sieves, thereby decreasing the rate of coke formation during the reaction, which in turn extends the catalyst's lifetime. Experimental results demonstrated that the catalyst's lifetime increased progressively with the addition of Ce. In the methanol-to-olefin reaction, the catalytic lifetime of the S-Z/Cu_0.05-Ce_0.05 samples reached 1440 min, approximately 480 min longer than that of the S-Z samples, while maintaining a selectivity for low-carbon olefins at around 89.6 %.