The role of mixed alkali metal cations on the formation of nanosized CHA zeolite from colloidal precursor suspension

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:604

Article

Ghojavand, Sajjad¹  Clatworthy, Edwin B.¹  Vicente, Aurelie¹  Dib, Eddy¹  Ruaux, Valerie¹  Debost, Maxime^1,2  El Fallah, Jaafar¹  Mintova, Svetlana¹ 

[1] Normandie Univ, Lab Catalyse & Spectrochim LCS, CNRS, UNICAEN,ENSICAEN, F-14000 Caen, France

[2] Normandie Univ, CRISMAT, CNRS, UNICAEN,ENSICAEN, F-14000 Caen, France

关键词: Nanozeolite;    Chabazite;    Colloidal suspension;    Crystallization;    Organic template-free;    Inorganic cation templating;   

DOI  :  10.1016/j.jcis.2021.06.176

来源: Elsevier

【 摘 要 】

A clear understanding of the crystal formation pathways of zeolites remains one of the most challenging issues to date. Here we investigate the synthesis of nanosized chabazite (CHA) zeolites using organic template-free colloidal suspensions by varying the time of aging at room temperature and the time of hydrothermal treatment at 90 degrees C. The role of mixed alkali metal cations (Na+, K+, Cs+) on the formation of CHA in the colloidal suspensions was studied. Increasing the aging time of the precursor colloidal suspension from 4 to 17 days resulted in faster crystallization of CHA nanocrystals (3 h instead of 7 h at 90 degrees C) to afford significantly smaller particles (60 nm vs 600 nm). During the crystallization a considerable change in the content of inorganic cations in the recovered solid material was observed to coincide with the formation of the CHA nanocrystals. The Na+ cations were found to direct the formation of condensed and pre-shaped aluminosilicate particles in the colloidal precursor suspensions, while K+ cations facilitated the formation of secondary building units (SBUs) of the CHA type framework structure such as d6r and cha cages, and the Cs+ cations promoted the long-range crystalline order facilitating the crystallization of stable zeolite nanocrystals. (C) 2021 Elsevier Inc. All rights reserved.

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