Mechanism of Ti(IV) incorporation onto the zeolite framework probed with XAFS

Abstract

Ti incorporation into aluminosilicate zeolite was reported earlier (Kwak et al., Catal. Lett. 37 (1996) 217). In this work, the mechanism of the titanium incorporation has been explored with Raman, laser light scattering and XAFS. Titanium tetraisopropoxide was converted into penta-valent Ti precipitates upon hydrolysis. Subsequent peptization with hydrochloric acid led to the formation of nano-sized titania soil containing polymeric Ti species. Mixing the Ti sol with silica sol resulted in the Ti-O-Si bond formation. The obtained Ti-Si sol has been successfully used for the crystallization of aluminosilicate zeolites. The catalytic activity of the partial oxidation of 2-butanol over Ti-NaY and Ti-silicalite was comparable to that of TS-1.