title: Optimizing the crystallinity and acidity of H-SAPO-34 by fluoride for synthesizing Cu/SAPO-34 NH3-SCR catalyst.
abstract: A series of H-SAPO-34 zeolites were synthesized by a hydrothermal method in fluoride media. The as-synthesized H-SAPO-34 zeolites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 physisorption, temperature-programmed desorption of NH3 (NH3-TPD) and nuclear magnetic resonance (NMR) measurements. The results showed that a certain concentration of F(-) anions promoted the nucleation and crystallization of H-SAPO-34. The H-SAPO-34 synthesized in the fluoride media showed high crystallinity, uniform particle size distribution, large specific surface area and pore volume, and enhanced acidity. Therefore, Cu/SAPO-34 based on the fluoride-assisted zeolite showed a broadened temperature window for the selective catalytic reduction of NO by NH3 (NH3-SCR) reaction due to the enhanced acidity of the zeolite and the improved dispersion of copper species.
authors.affiliation: The Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China. Electronic address: j-ma09@mails.tsinghua.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.affiliation: Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
authors.forename: Zhichun
authors.initials: Z
authors.lastname: Si
authors.affiliation: The Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China; Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wu
authors.affiliation: The Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China; Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China. Electronic address: duanweng@tsinghua.edu.cn.
authors.forename: Duan
authors.initials: D
authors.lastname: Weng
authors.affiliation: The Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D005459:Fluorides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017641:Zeolites / Q000032:analysis*
chemical_list: D017641:Zeolites; D003300:Copper; D005459:Fluorides
keywords: Acidity; Crystallinity; Fluoride media; H-SAPO-34; Selective catalytic reduction (SCR) of NO