Synthesis of mesoporous SiO2 aerogel/WxTiO2 nanocomposites with high adsorptivity and photocatalytic activity

Abstract

Mesoporous SiO2 aerogel/WxTiO2 nanocomposites with high adsorptivity and photocatalytic activity were prepared by hydrothermal deposition method using SiO2 aerogel as carrier. The morphology and microstructure of the SiO2 aerogel/WxTiO2 nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption measurements. The results indicated that the SiO2 aerogel/WxTiO2 nanocomposites exhibited sponge-like network-structure with higher pore volume and anatase TiO2 crystallinity. Increasing the SiO2 aerogel content and ethanol/water volume ratio in the precursor solution is favorable for improving the specific surface area and pore volume of SiO2 aerogel/WxTiO2 composite particles. Under the conditions of Si/Ti mol ratio >0.6 and ethanol/water volume ratio >1:3, the specific surface area and pore volume of the as-prepared SiO2 aerogel/WxTiO2 nanocomposites could attain to 195.7–271.3m2/g and 0.86–1.11mL/g, respectively. Moreover, the as-prepared SiO2 aerogel/WxTiO2 nanocomposites exhibited higher adsorptivity and photocatalytic activity. Particularly, the synthesized SiO2 aerogel/WxTiO2 nanocomposite sample 0.9STW-1:3 (Vethanol/Vwater=1/3) exhibited highest efficiency for removing the Rhodamine B in the simulated wastewater. In addition, the as-prepared SiO2 aerogel/WxTiO2 composites still exhibited higher adsorption efficiency and photocatalytic activity after 4 cycles.