Preparation of mesoporous TiO_2–SiO_2 by ultrasonic impregnation method and effect of its calcination temperature on photocatalytic activity

摘要

This article presents a novel procedure to synthesis mesoporous TiO2-SiO2 structure via ultrasonic impregnation method. Mesoporous silica SBA-15 as a host structure was first prepared. Then, the prepared host structure was mixed with a homogenized solution of TiO2 precursor under ultrasonic condition at 40 degrees C. To understand the chemical composition and structural properties of the synthesized powder, several characterization techniques such as powder X-ray diffraction, small-angle X-ray scattering, nitrogen adsorption, X-ray photoelectron spectroscopy, transmission electron microscopy, field-emission scanning electron microscopy and energy dispersive X-ray were employed. Photocatalytic activity of the calcined materials at various temperatures (400 degrees C, 600 degrees C, and 800 degrees C) was evaluated by degradation of methylene blue solution under UV light. The anatase crystals were the only detected phase until 800 degrees C due to formation of Ti-O-Si bonds. Photo-degradation results revealed that all of synthesized samples possess much more photocatalytic activity than commercial TiO2. In addition, a higher photocatalytic efficiency was achieved at higher calcination temperature owing to more degree of crystallinity.