A novel active carbon reducing process was developed for the synthesis of titanium dioxide with oxygen vacancy. In this process a nanocomposite of hydrolyzed titanium(IV) tetra-isopropoxide and the active carbon was annealed in air. The formation reaction, visible-light absorption, and visible-light sensitive photocatalytic activity of the titanium dioxide with oxygen vacancy samples were investigated using XRD, TG-DTA analyses, FE-SEM, EDS, and measurements of electric conductivity, BET specific surface area and photocatalytic activity. The non-stoichiometric titanium dioxide with oxygen vacancy sample had a rutile structure and its chemical formula could be written as Ti(IV)1−xTi(III)xO(2−x/2)□x/2, where □ was oxygen vacancy. The oxygen vacancy was introduced into the rutile structure by reducing reaction of the active carbon in a phase transformation process from anatase to rutile. The samples showed visible-light absorption with an absorption edge around 570nm and high surface visible-light sensitive photocatalytic activity.

Synthesis of Titanium Dioxide with Oxygen Vacancy and Its Visible-Light Sensitive Photocatalytic Activity. S.Yang, W.Tang, Y.Ishikawa, Q.Feng: Materials Research Bulletin, 2011, 46[4], 531-7