TS-1 zeolite with homogeneous distribution of Ti atoms in the framework: synthesis, crystallization mechanism and its catalytic performance

The distribution of titanium (Ti) active sites in the framework of TS-1 zeolite is one of the critical factors affecting its catalytic performance, since it can influence accessibility of the Ti active sites and the catalytic utilization of Ti atoms. Here, TS-1 zeolite with homogeneous distribution of titanium atoms in the framework (named BUS-TS-1) is successfully synthesized via bottom-up strategy at high basicity conditions, and BUS-TS-1 zeolite exhibits better catalytic performance for both olefin and alkane oxidation. The comprehensive explorations on the crystallization behavior of BUS-TS-1 zeolite show that, the gripper-like silicon species, as condensed matter in Q(2) and Q(3) states (detected by Si-29 NMR), can be obtained by the condensation of tetraethyl orthosilicate (TEOS) at high alkalinity conditions. The gripper-like silicon species can condense with Ti-OH to form stable and isolated Si-O-Ti species, so that the phase transfer rates of Si and Ti species match during the entire crystallization process, resulting in the homogeneous distribution of Ti atoms. This work offers a useful strategy for the synthesis of high-performance catalysts by regulating the distribution of Ti active-site within TS-1 framework. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The homogeneous distribution of titanium atoms in TS-1 zeolite (BUS-TS-1) synthesized under high basicity conditions through a bottom-up strategy leads to better catalytic performance for both olefin and alkane oxidation. Gripper-like silicon species can condense with Ti-OH to form stable Si-O-Ti species, ensuring the phase transfer rates match during crystallization and result in the uniform distribution of Ti atoms. This work offers a useful strategy for synthesizing high-performance catalysts by regulating the distribution of Ti active sites within the TS-1 framework.