Template-free sol-gel preparation and characterization of free-standing visible light responsive C,N-modified porous monolithic TiO2

Visible light responsive C,N-modified porous monolithic titania (MTf) has been successfully synthesized. The template-free sol-gel synthesis method accompanied by phase separation and in situ C,N-modification has been used. The molar ratio of water to tetrabutyl titanate (f) in starting solution plays an important role in the porous structure and photoactivity of MTf. Scanning electron microscopy (SEM) analysis and N2 adsorption-desorption analysis show that MTf possess mesoporous structure as well as macroporous structure. MT22 has been further characterized by using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). The results show that both nitrogen and carbon elements exist in MT22 and result in the visible light photocatalytic activity of MT22. The observed reaction rate of decolorization of methyl orange is 0.0026 min-1.