Fluoride-mediated nano-sized high-silica ZSM-5 as an ultrastable catalyst for methanol conversion to propylene

Fluoride mediated nano-sized ZSM-5 (ZSM-5-F) with a high Si/Al ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene (MTP) reaction. High propylene selectivity (45%) was similar to ZSM-5-OH synthesized via a hydroxide route. However, ZSM5-F showed much longer lifetime (305 h) compared with ZSM-5-OH (157 h) in spite of similar crystal size and aluminum content. Characterization by NH3-TPD, Py-IR, OH-IR, SEM, TG-DTA, XRD and H-1 MAS NMR techniques indicated that the enhanced catalytic performance of ZSM-5-F is attributed to the fewer structural defects in the form of internal silanol groups and silanol nests. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.