Carbon-Deposited TiO2: Synthesis, Characterization, and Visible Photocatalytic Performance

Abstract

Carbon-deposited TiO 2 (TiO 2 @C) was prepared with a one-pot hydrothermal process by using glucose as a carbon source. The physical properties of TiO 2 @C were studied by XRD, TG-DTA, HRTEM, and UV−vis diffuse reflectance spectra (DRS), while the chemical states of carbon were discussed via X-ray photoelectron spectroscopy (XPS). A graphite carbon layer was formed out of the TiO 2 grain during the hydrothermal process via the dehydration of glucose, which consisted of not only C n but also C—OH (and C—O—C) and C═O (and COO). TiO 2 @C has remarkable light absorption in the visible region. It was found that the photocatalytic activity of TiO 2 @C was greatly enhanced compared to noncarbon-TiO 2 under visible irradiation. The photocatalyst with the highest photocatalytic activity for the degradation of Acid Orange 7 (AO7) was G15 TiO 2 @C, while that for the degradation of 2,4-dichlorophenol (2,4-DCP) was G5 TiO 2 @C. Two kinds of sensitization processes, carbon sensitization and dye sensitization, are responsible for the visible light-induced photocatalysis of TiO 2 @C. Carbon sensitization reached its optimal condition in G5, while dye sensitization occurred in its maximum efficiency in G15.