Fabrication and morphological control of three-dimensional cage type mesoporous titanosilicate with extremely high Ti content

Abstract

TiSBA-1 materials with extremely high Ti content, up to silicon to titanium ratio ( n Si/ n Ti) of 2.4, have been successfully prepared through direct synthesis method by controlling the molar ratio of hydrochloric acid to silicon ( n HCl/ n Si). It has been found that the amount of Ti content and the structure of the TiSBA-1 can easily be controlled by the simple adjustment of n HCl/ n Si ratio. X-ray diffraction pattern (XRD) of the obtained materials revealed that the materials are highly ordered and possess cubic three-dimensional cage type structure with open windows. N 2 adsorption–desorption measurement confirmed the narrow pore size distribution, high specific surface area (1317–1491 m 2 g −1), and large specific pore volume (0.68–0.75 cm 3 g −1) for all the samples. UV–vis DR spectra of the prepared materials confirmed that Ti atoms are exclusively incorporated within silica framework and occupy the tetrahedral position while the presence of isolated bulk titania could be negligible. Morphologies of the TiSBA-1 materials have been also controlled by simply adjusting the n Si/ n Ti ratio. With the appropriate Ti content, TiSBA-1 materials can be obtained as regular fine spheres. Moreover, the detailed mechanism on the morphological and phase transition control, and the incorporation of high amount of Ti in the framework of TiSBA-1 materials has been also discussed in detail.