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 Q² and Q³ states (detected by ²⁹Si 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.