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Solvent-Free Synthesis of Mg-Incorporated Nanocrystalline SAPO-34 Zeolites via Natural Clay for Chloromethane-to-Olefin Conversion

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journal contribution
posted on 05.03.2020, 20:11 by Ting Wang, Chengguang Yang, Shenggang Li, Gan Yu, Ziyu Liu, Hui Wang, Peng Gao, Yuhan Sun
Isomorphous substitution is an important approach in modifying the acidity and pore structure of nanoscale SAPO-34 zeolites, which can bring about active sites stemming from heteroatoms. However, it remains a major challenge to use conventional hydrothermal methods to synthesize cost-effective, all-framework heteroatoms, and environmentally friendly catalysts. Herein, an efficient and eco-friendly approach is developed for the solvent-free synthesis of Mg-incorporated SAPO-34 (MgAPSO-34) with Mg content of up to 6.65% and smaller crystal size (50 nm) by taking advantage of a natural layered Mg-rich aluminosilicate clay mineral. Characterizations with X-ray diffraction, magic-angle spinning NMR, and ultraviolet–visible spectroscopies show that all the Mg can enter the zeolitic framework by replacing the Al sites. In addition, MgAPSO-34 with the incorporation of a proper amount of Mg exhibits a high specific surface area and moderate acidity and thus shows excellent performance and anticoke capacity in the chloromethane-to-olefin reaction. The combination of “green” synthesis and “superior” catalytic properties allows for low-cost and environmentally friendly synthesis of isomorphous substituted SAPO-34 zeolites with high crystallinity and high quality.

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