Synthesis and Photocatalytic Activity of TiOX Powders with Different Oxygen Defects

Abstract

The novel carbon- or chromium-doped TiOX photocatalysts with different oxygen defects were synthesized by mechanochemical technique and heating process. The samples were characterized by X-ray diffraction, UV-vis spectrophotometer, and fluorescence spectrometer. Carbon and chromium species were incorporated into TiOX crystal matrix. The mass fraction of Ti7O13 in TiOX photocatalysts could be tunable through carbon or chromium doping. The mass fraction of Ti7O13 could be an indication of the degree of oxygen defects (the concentration of Ti3+) in the TiOX. The degree of oxygen defects increased for carbon doping, while the degree of oxygen defects decreased for chromium doping. The photocatalytic activity measurement results showed that photodegradation rate of methyl orange reached the maximum value with mass fraction of Ti7O13 of about 66.93%, but the photodegradation rate decreased when mass fraction of Ti7O13 is raised further. In addition, the origin of absorption in the visible spectral range for carbon-doped TiOX as well as the effect of band gap on photocatalytic activity has also been discussed in this paper.