Synthesis of carbon self-doped titanium dioxide and its activity in the photocatalytic oxidation of styrene under visible light irradiation

Abstract

Carbon self-doped titanium dioxide (C/TiO2) photocatalyst was synthesized by a simple sol-gel method using titanium isopropoxide as both the titanium precursor and carbon source. The effects of calcination temperatures in the range of 300 to 700 °C to the structure and physicochemical properties of the C/TiO2 were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray (EDX), Fourier transform infrared (FTIR) spectroscopy, UV-visible diffuse reflectance (UV-Vis DR) spectroscopy, photoluminescence spectroscopy, N2 adsorption-desorption and X-ray photoelectron spectroscopy (XPS). XPS results proved the presence of self-doped carbon at the interstitial and substitutional lattice of TiO2. The C/TiO2 calcined at 300 and 400 °C (C/TiO2-300 and C/TiO2-400, respectively) showed mesoporous characteristic and large surface area of about 100 m2 g-1. The C/TiO2 photocatalysts were then tested in the photo-oxidation of styrene under visible light irradiation with aqueous hydrogen peroxide as the oxidizing agent. The C/TiO2 photocatalysts were successfully activated under the irradiation of visible light, where C/TiO2-300 and C/TiO2-400 showed the highest total concentration of products (benzaldehyde and styrene oxide) at 1.1 mmol and 1.0 mmol, respectively.