Chinese Journal of Catalysis ›› 2021, Vol. 42 ›› Issue (12): 2189-2196.DOI: 10.1016/S1872-2067(21)63882-2

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Amino acid-assisted synthesis of TS-1 zeolites containing highly catalytically active TiO6 species

Yuyao Wanga, Li Lia, Risheng Baia, Shiqin Gaoa, Zhaochi Fengc, Qiang Zhanga,#(), Jihong Yua,b,*()   

  1. aState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, Jilin, China
    bInternational Center of Future Science, Jilin University, Changchun 130012, Jilin, China
    cState Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2021-05-08 Accepted:2021-05-08 Online:2021-12-18 Published:2021-07-07
  • Contact: Qiang Zhang,Jihong Yu
  • About author:# E-mail: qiangz@jlu.edu.cn
    * Tel/Fax: +86-431-85168608; E-mail: jihong@jlu.edu.cn;
  • Supported by:
    National Natural Science Foundation of China(21920102005);National Natural Science Foundation of China(21835002);National Natural Science Foundation of China(21621001);111 Project(B17020)

Abstract:

Tailoring the Ti coordination states in titanosilicate zeolites to simultaneously improve feedstock conversion and maximize the target product selectivity remains a challenge in the pursuit of high-performance catalysts for selective oxidation reactions. Herein, we provide a facile strategy to synthesize hierarchical anatase-free TS-1 (MFI-type) zeolites with tetrahedrally coordinated (TiO4) and octahedrally coordinated Ti species (TiO6). The TiO4 species provide high epoxide selectivity, while the TiO6 species afford improved alkene conversion. This strategy is achieved by synergistically using an L-lysine-assisted approach and a two-step crystallization; the two-step crystallization approach prevents the formation of anatase TiO2, while L-lysine stabilizes the TiO6 species and ensures efficient incorporation of TiO6 into the anatase-free TS-1 zeolites. Compared with their conventional counterparts, which only contain TiO4 species, the as-prepared TS-1 zeolites (Si/Ti = 36.9) result in a higher 1-hexene conversion (33%), higher TON value (153), and comparable epoxide selectivity (95%). This synthetic strategy provides avenues to tailor the amount and distribution of Ti species in titanosilicate zeolites to achieve high catalytic performances in various processes.

Key words: TS-1 zeolites, Ti species, L-Lysine-assisted approach, 1-Hexene epoxidation