Enhanced visible-light photocatalytic oxidation capability of carbon-doped TiO2 via coupling with fly ash

Abstract

A carbon-doped TiO 2 /fly ash support (C-TiO 2 /FAS) composite photocatalyst was successfully synthesized through sol impregnation and subsequent carbonization. The carbon dopants were derived from the organic species generated during the synthesis of the C-TiO 2 /FAS composite. A series of analytical techniques, such as scanning electron microscopy (SEM), attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), were used to characterize the properties of the prepared samples. The results indicated that C-TiO 2 was successfully coated on the FAS surface. Coupling between C-TiO 2 and FAS resulted in the formation of Si–O–C and Al–O–Ti bonds at their interface. The formation of Si–O–C and Al–O–Ti bonds gave rise to a positive shift of the valence band edge of C-TiO 2 and enhanced its oxidation capability of photogenerated holes as well as photodegradation efficiency of methyl orange. Moreover, the C-TiO 2 /FAS photocatalyst exhibited favorable reusability and separability. This work may provide a new route for tuning the electronic band structure of TiO 2 . The coupling between C-TiO 2 and FAS led to a positive shift of the valence band edge of C-TiO 2 , enhancing its oxidation capability of photogenerated holes and improving its methyl orange photodegradation efficiency.