Synthesis and characterization of carbon-doped titanium dioxide driven visible light photocatalysts

Abstract

The carbon-doped titanium dioxide (C-doped TiO₂) photocatalysts were synthesized by a sol-gel method without the addition of external carbon sources.  Titanium (IV) butoxide and ethanol were used as the starting materials in which the titanium (IV) butoxide act as a titanium precursor and also a carbon sources.  The physical properties of the C-doped TiO₂ synthesized at different calcination temperatures were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), diffuse reflectance UV-Vis spectroscopy (DR UV-Vis), and photoluminescence (PL).  The peak of carbon at about 1376 to 1538 cm^-1 from FTIR spectra of carbon-doped TiO₂ showed the decrease in intensity as the calcination temperature increases to 300 ºC and disappears when calcined at 400 ºC.  The C-doped TiO₂ which calcined at 200 and 300 ºC have the ability to absorb visible light as demonstrated in DR UV-Vis spectra while PL analysis gives a result of very small emission intensity at 465 nm.  The photocatalytic activity of synthesized photocatalyst was examined by degradation of methylene blue as a model pollutant for 240 min reactions under visible light irradiation.  The C-doped TiO₂ which calcined at 300 ºC was found to be an active photocatalyst under visible light irradiation which exhibits 10 percent degradation of methylene blue.  It can be deduced that the carbon doping with a controlled calcination temperature have contribute to the photocatalytic activity of the photocatalysts.