Two-step synthesis of Ti-rich surface TS-1 with controllable microenvironment of titanium species

It is significant to improve the catalytic activity of TS-1 by increasing the content of framework titanium and enhancing the accessibility of active titanium sites. However, developing a simple and economical strategy for modulating the coordination environments and the spatial distribution of titanium species is still a challenge. Here, we constructed anatase-free TS-1 with abundant framework titanium species and Ti-rich surface by a simple two-step crystallization strategy. The effects of the crystallization temperature and time of the first stage on the properties of zeolite have been investigated in detail. The TS-1 with a Ti-rich surface showed a higher conversion of phenol and selectivity to dihydroxylbenzene in phenol hydroxylation reaction compared with traditional TS-1, and it still remained the superior catalytic performance after five cycles. The novel strategy will provide a new perspective for the construction of TS-1 with controllable active Ti species.