Oriented zeolite MFI monolayer films on metal substrates by in situ crystallization

Continuous b-oriented zeolite MFI monolayer films (<0.4 μm thick) were prepared by in situ crystallization on metal substrates (stainless steel and aluminum alloy) using a synthesis solution 0.32TPAOH:TEOS:165H 2 O (TPAOH: tetrapropylammonium hydroxide, TEOS: tetraethylorthosilicate). Effects of crystallization temperature and time, surface roughness, position and chemical nature of the substrate, and aging time of the synthesis solution were investigated and a mechanism for the b-oriented monolayer thin film formation was discussed. The supported films were characterized with scanning electron microscopy and X-ray diffraction. Polishing of the film with a normal lab polisher leads to a continuous ultrathin zeolite film with a surface roughness less than 0.05 μm.