Ultra-selective high-flux membranes from directly synthesized zeolite nanosheets

Mi Young Jeon, Donghun Kim, Prashant Kumar, Pyung Soo Lee, Neel Rangnekar, Peng Bai, Meera Shete, Bahman Elyassi, Han Seung Lee, Katabathini Narasimharao, Sulaiman Nasir Basahel, Shaeel Al-Thabaiti, Wenqian Xu, Hong Je Cho, Evgenii O. Fetisov, Raghuram Thyagarajan, Robert F. Dejaco, Wei Fan, K. Andre Mkhoyan, J. Ilja SiepmannMichael Tsapatsis

Research output: Contribution to journalArticle

170 Scopus citations

Abstract

A zeolite with structure type MFI is an aluminosilicate or silicate material that has a three-dimensionally connected pore network, which enables molecular recognition in the size range 0.5-0.6 nm. These micropore dimensions are relevant for many valuable chemical intermediates, and therefore MFI-type zeolites are widely used in the chemical industry as selective catalysts or adsorbents. As with all zeolites, strategies to tailor them for specific applications include controlling their crystal size and shape. Nanometre-thick MFI crystals (nanosheets) have been introduced in pillared and self-pillared (intergrown) architectures, offering improved mass-transfer characteristics for certain adsorption and catalysis applications. Moreover, single (non-intergrown and non-layered) nanosheets have been used to prepare thin membranes that could be used to improve the energy efficiency of separation processes. However, 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 non-exfoliated particles. This top-down method is time-consuming, costly and low-yield and it produces fragmented nanosheets with submicrometre 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).

Original languageEnglish (US)
Pages (from-to)690-694
Number of pages5
JournalNature
Volume543
Issue number7647
DOIs
StatePublished - Mar 30 2017

How much support was provided by MRSEC?

  • Shared

Reporting period for MRSEC

  • Period 3

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't

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