Ionothermal Synthesis of Triclinic SAPO-34 Zeolites

Li Han,Jun Xu,Xinxin Yan,Tianliang Lu,Lulu Guo,Zheng Wang,Yanan Duan,Yuzhong Zhan,Jianfeng Wang

doi:10.3390/catal11050616

Li Han, Jun Xu + Show 7 more

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https://doi.org/10.3390/catal11050616

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Abstract

A triclinic SAPO-34 molecular sieve was synthesized ionothermally. The as-synthesized products were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), nuclear magnetic resonance (NMR), fourier infrared spectrometer (FT-IR) and thermogravimetric (TG) analyses. The formation mechanism of the hierarchical porous triclinic SAPO-34 zeolites and the factors affecting the morphology of the SAPO-34 molecular sieve were investigated. The results show that the formation mechanism of the hierarchical pores is in accordance with Ostwald ripening theory, and the accumulation of grains constitutes the existence of mesopores and macropores. The crystallization temperature, ionic liquid type, and organic amines can effectively change the morphology and crystallinity of the SAPO-34 molecular sieve. The crystallization temperature, ionic liquid and template have great influence on the (111) crystal plane, thus affecting the morphology of the molecular sieve. Moreover, it can be proven through NMR and TG analyses that ionic liquids and organic amines can be used as structure directing agents together.

Highlights

Zeolites and zeotypes have emerged as some of the most significant crystalline microporous materials
The growth of the (111) crystal plane is further promoted with increasing crystallization temperature, which favors the formation of cubic crystals
The morphology and crystallinity of the SAPO-34 molecular sieve can be controlled by the crystallization temperature, organic amines and the type of ionic liquids

Summary

Introduction

Zeolites and zeotypes have emerged as some of the most significant crystalline microporous materials. The silicoalumino-phosphate zeolite SAPO-34 with a CHA framework is an important microporous crystal with uniform and intricate channels, high specific surface area, adsorption capacity, and high thermal and hydrothermal stabilities, which have been widely used in catalysis [4,5], adsorption, ion-exchange, separation [6], etc. The performance in these fields is greatly influenced by the structure and properties of the SAPO-34 zeolite. The synthesis methods and conditions have a substantial impact on the structure and properties of SAPO-34 zeolite

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