A facile fabrication of highly b-oriented MFI zeolite films in the TEOS-TPAOH-H2O system without additives

摘要

A facile secondary growth method for fabrication of highly b-oriented MFI zeolite films is demonstrated. This method enables the growth of b-oriented MFI seed monolayers into highly b-oriented dense films in the TEOS-TPAOH-H2O system without any additive or extra treatment. Suppression of twin growth is achieved via the increase of water content in the synthesis solution. A clear correlation between the film orientation and the synthesis composition for secondary growth is presented. Compared with previously reported strategies in controlling the orientation of MFI zeolite films, this method offers greater operating window of the synthesis composition (H2O/Si = 1500-3000, TPA(+)/Si = 0.1-0.5, OH-/Si = 0.1-0.2) and synthesis condition (150-180 degrees C, 4-8 h). The thickness of b-oriented MFI films (370 nm-610 nm) can be tuned by adjusting the water amount or the synthesis condition. The new synthesis method uses lower amount of organic template and silica source making it potentially more economical and environmentally friendly and thus attractive for industrial implementation. (C) 2016 Elsevier Inc. All rights reserved.