Until now, single MFI nanosheets have been prepared using a multi-step approach based on the exfoliation of layered MFI, followed by centrifugation to remove nonexfoliated particles. This top-down method is time-consuming, costly and low-yield and it produces fragmented nanosheets with sub micrometre lateral dimensions. Alternatively, direct (bottom-up) synthesis could produce high-aspect-ratio zeolite nanosheets, with improved yield and at lower cost. Here we use a nanocrystal-seeded growth method triggered by a single rotational intergrowth to synthesize high-aspect-ratio MFI nanosheets with a thickness of 5 nanometres (2.5 unit cells). These high-aspect-ratio nanosheets allow the fabrication of thin and defect-free coatings that effectively cover porous substrates. These coatings can be intergrown to produce high-flux and ultra-selective MFI membranes that compare favourably with other MFI membranes prepared from existing MFI materials (such as exfoliated nanosheets or nanocrystals).

• 이평수(한국화학연구원 분리막 연구센터, Korea Research Institute of Chemical Technology) | Pyung Soo Lee
• 박유인(한국화학연구원 분리막 연구센터, Korea Research Institute of Chemical Technology) | You-in Park
• 전미영(University of Minnesota, Chemical Engineering Dept.) | Miyoung Jeon
• 김동훈(University of Minnesota, Chemical Engineering Dept.) | Donghun Kim
• Michael Tsapatsis(University of Minnesota, Chemical Engineering Dept.)