Size controllable synthesis of ZSM-5 zeolite and its catalytic performance in the reaction of methanol conversion to aromatics

• Published in: Royal Society open science Vol. 9; no. 3; p. 211284
• Main Authors: Niu, Xianjun, Bai, Yang, Du, Yi-En, Qi, Hongxue, Chen, Yongqiang
• Format: Journal Article
• Language: English
• Published: England The Royal Society 01.03.2022
• Subjects: Chemistry; crystal size; methanol to aromatics; silicalite-1; ZSM-5 zeolites; methanol to aromatics; silicalite-1; crystal size; ZSM-5 zeolites
• ISSN: 2054-5703; 2054-5703
• DOI: 10.1098/rsos.211284

ZSM-5 zeolites were hydrothermally synthesized with commercial silica sol, and the crystal size was controlled by adding silicalite-1 seed in the synthetic system. The crystal size of ZSM-5 was affected by the crystallization time of seed, seed content and seed size. ZSM-5 zeolites with controllable particle size in the range of 200-2200 nm could be obtained. The prepared samples with different particle sizes were used for the reaction of methanol conversion to aromatics (MTA). The results suggested that the HZSM-5 catalyst with small crystal size showed much longer catalyst lifetime and higher selectivity for C hydrocarbons and aromatics, especially C aromatics in the MTA reaction. Moreover, the introduction of zinc (Zn) into the HZSM-5 zeolites can considerably promote the selectivity to aromatics in the products. Zn modified HZSM-5 zeolites with different Zn loading amounts were prepared by the incipient wetness impregnation method, and the highest aromatics selectivity was obtained when the Zn loading was 1.0%. The improvement of methanol aromatization was ascribed to the synergistic effect of Brønsted acid sites and the newly formed Zn-Lewis acid sites.