ECNU-36: A Quasi-Pure Polymorph CH Beta Silicate Composed of Hierarchical Nanosheet Crystals for Effective VOCs Adsorption

Meichen Jiao; Ju Huang; Hao Xu; Jingang Jiang; Yejun Guan; Yanhang Ma; Peng Wu

doi:10.1002/anie.202008327

ECNU-36: A Quasi-Pure Polymorph C_H Beta Silicate Composed of Hierarchical Nanosheet Crystals for Effective VOCs Adsorption

Angew Chem Int Ed Engl. 2020 Sep 21;59(39):17291-17296. doi: 10.1002/anie.202008327. Epub 2020 Jul 28.

Authors

Meichen Jiao¹, Ju Huang², Hao Xu¹, Jingang Jiang¹, Yejun Guan¹, Yanhang Ma², Peng Wu¹

Affiliations

¹ Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, North Zhongshan Rd. 3663, Shanghai, 200062, China.
² School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.

PMID: 32558185
DOI: 10.1002/anie.202008327

Abstract

A quasi-pure C_H polymorph of microporous zeolite beta, named ECNU-36, was obtained as a highly crystalline silicate using 1,5-bis(tetramethylimidazolium) hydroxide as organic structure-directing agent (OSDA) in fluoride media. An appropriate concentration of free fluoride in the synthetic mother liquor was crucial to purify the C_H -phase. The framework structure of ECNU-36 consists of polymorph C_H (>95 %) and polymorph B, elucidated by a combination of PXRD data, DIFFaX simulation, EDT, and HRTEM techniques. For the first time, the framework structure of beta C_H polymorph was directly confirmed and solved using electron diffraction data. The pure-silica ECNU-36 showed an unusual crystal morphology, composed of stacked nanosheets, with typical 17 nm thickness and exposed {100} facets, which exhibited attractive adsorption performance for hydrocarbons and aromatics.

Keywords: adsorption; all-silica; high hydrophobicity; polymorph CH; zeolite beta.

Abstract

Grants and funding