Ammonia-assisted dry-gel conversion for preparation of TS-1 with enriched Ti(OSi)3OH active sites

IF 4.8 3区材料科学 Q1 CHEMISTRY, APPLIED

Microporous and Mesoporous Materials Pub Date : 2025-03-10 DOI:10.1016/j.micromeso.2025.113595

Huanhao Lin , Xin Sun , Yucheng Jin , Yunkai Yu , Yueming Liu

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引用次数: 0

Abstract

Defective Ti(IV) species, i.e. Ti(OSi)₃OH, are highly active catalytic sites within the TS-1 framework, and developing efficient methods to enrich these species has attracted significant attention from both academia and industry sectors. Herein, we developed an ammonia-assisted dry-gel conversion (DGC) method to synthesize TS-1-AM enriched with Ti(OSi)₃OH species using NH₃ (ammonia, AM) as a modifier. Comprehensive characterization using XRD, UV–Vis, SEM, XPS, pyridine-IR, solid-state MAS NMR confirmed the abundant presence of Ti(OSi)₃OH species in TS-1-AM. The modified catalyst demonstrated exceptional performance in alkene epoxidation, achieving approximately 150% higher catalytic activity compared to the parent TS-1, while maintaining excellent cycling stability. Further studies revealed that the synergistic effect of NH₃ and H₂O molecules facilitated the selective cleavage of framework Si-O-Ti bonds, promoting the conversion of Ti(OSi)₄ species to Ti(OSi)₃OH species. Furthermore, the condensation of surface silica hydroxyls, particularly silica hydroxyl nests, enhanced surface hydrophobicity. This straightforward DGC method provides an efficient approach for synthesizing titanosilicates enriched with highly active Ti(OSi)₃OH species.

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来源期刊

Microporous and Mesoporous Materials 化学-材料科学：综合

CiteScore

10.70

自引率

5.80%

发文量

649

审稿时长

26 days

期刊介绍： Microporous and Mesoporous Materials covers novel and significant aspects of porous solids classified as either microporous (pore size up to 2 nm) or mesoporous (pore size 2 to 50 nm). The porosity should have a specific impact on the material properties or application. Typical examples are zeolites and zeolite-like materials, pillared materials, clathrasils and clathrates, carbon molecular sieves, ordered mesoporous materials, organic/inorganic porous hybrid materials, or porous metal oxides. Both natural and synthetic porous materials are within the scope of the journal. Topics which are particularly of interest include: All aspects of natural microporous and mesoporous solids The synthesis of crystalline or amorphous porous materials The physico-chemical characterization of microporous and mesoporous solids, especially spectroscopic and microscopic The modification of microporous and mesoporous solids, for example by ion exchange or solid-state reactions All topics related to diffusion of mobile species in the pores of microporous and mesoporous materials Adsorption (and other separation techniques) using microporous or mesoporous adsorbents Catalysis by microporous and mesoporous materials Host/guest interactions Theoretical chemistry and modelling of host/guest interactions All topics related to the application of microporous and mesoporous materials in industrial catalysis, separation technology, environmental protection, electrochemistry, membranes, sensors, optical devices, etc.