Uniform hierarchical MFI nanosheets prepared via anisotropic etching for solution-based sub-100-nm-thick oriented MFI layer fabrication.

Abstract

Zeolite nanosheets have shown unprecedented opportunities for a wide range of applications, yet developing facile methods for fabrication of uniform zeolite nanosheets remains a great challenge. Here, a facile approach involving anisotropic etching with an aqueous solution of tetrapropylammonium hydroxide (TPAOH) was developed for preparing uniform high-aspect ratio hierarchical MFI nanosheets. In addition, the mechanism associated with the formation of MFI nanosheets was proposed. In the next step, a dynamic air-liquid interface-assisted self-assembly method and single-mode microwave heating were used for <i>b</i>-oriented MFI nanosheets monolayer deposition and controlled in-plane solution-based epitaxial growth, respectively, ensuring the formation of well-intergrown <i>b</i>-oriented MFI layers with sub-100-nm thickness. Moreover, our study indicated that <i>b</i>-oriented ultrathin MFI layers could be fabricated on diverse substrates demonstrating excellent anticorrosion capacity, ionic sieving properties, and <i>n</i>-/<i>i</i>-butane isomer separation performance.