Synthesis of titanium dioxide with oxygen vacancy and its visible-light sensitive photocatalytic activity

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 nonstoichiometric titanium dioxide with oxygen vacancy sample has a rutile structure and its chemical formula can be written as Ti(IV)1−xTi(III)xO(2−x/2)□x/2, where □ is 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 570 nm and high surface visible-light sensitive photocatalytic activity.