Steam-assisted synthesis of zeolite films from spin-coated zeolite precursor coatings

Abstract

Smooth and homogeneous Silicalite-1 films were synthesized on different supports (silicon, glass and stainless steel) by a steam-assisted crystallization method from zeolite precursor solutions diluted with different alcohols (methanol, ethanol, 2-propanol and 1-butanol). The use of the spin-coating technique for the preparation of the precursor films produced uniform coatings. Only a limited amount of SDA was required, and negligible amounts of waste products were formed (< 0.2 g) in the method. The type of alcohols used for film preparation significantly influenced the crystal morphology, film thickness and orientation. Preferentially b-oriented Silicalite-1 films were synthesized from a methanol-diluted precursor solution after 3 days of steaming. Thin and homogeneous Silicalite-1 films with a thickness of 800 nm were prepared from a 2-propanol-diluted precursor solution. It was also observed that the type of support affects the film morphology as the silica-containing supports were found to take part in the crystallization process. The steamed Silicalite-1 films were mechanically stable as no film detachment was observed under SEM analysis after both calcination and ultrasonic treatment.