Calcination-Free Fabrication of Highly b-Oriented Silicalite-1 Zeolite Films by Secondary Growth in the Absence of Organic Structure-Directing Agents

Abstract

Calcination-free fabrication of highly b-oriented silicalite-1 (S-1) zeolite films in the absence of organic structure-directing agents (OSDAs) is attractive but still challenging. Herein, for the first time, we show a novel route for calcination-free synthesis of a b-oriented S-1 zeolite film in the absence of OSDAs. The key to this success is a rational secondary growth of zeolite crystals on the surface of supports by avoidance of the formation of zeolite nuclei in the system due to the absence of OSDAs. Because of OSDA-free synthesis of S-1, it not only reduces the cost of zeolite films but also avoids the calcination of OSDAs in the synthesis, thus avoiding the formation of cracks in the zeolite films. In addition, the calcination-free fabrication is favorable for reduction of zeolite film defects such as a terminal OH group. As a result, the zeolite films obtained from this work exhibit higher hydrophobicity than the conventional one. Furthermore, the current polarization curve of this S-1 zeolite film shows excellent corrosion resistance. The aforementioned features would be potentially important for industrial application of zeolite films in the near future.