Dopant-free anatase titanium dioxide as visible-light catalyst: Facile sol–gel microwave approach

• Low temperature crystallization of TiO2 is being reported.
• Enhanced visible light activity and simplicity are the novelty of this work.
• Enhanced activity is explained by the oxygen vacancy defect.

Nanocrystalline anatase TiO2 has been prepared by a low temperature novel route following microwave exposure to convert sol–gel precursor to crystalline titanium dioxide and the features are compared with that obtained by conventional calcination. Predominantly, the microwave process results in uniform elongated rod like particles which is distinct from the usual calcination process adopted for sol–gel synthesized titania. Microwave treatment for 5 min results an enhanced visible-light activity for TiO2 samples and is higher than commercial Degussa TiO2 under identical conditions of experiment. The presence of oxygen vacancy defects are possibly responsible for the activity of microwave treated titania samples. Crystallinity of TiO2 particles are greatly affected by the initial precursor volume than duration of microwave exposure which leads to the possibility of a continuous microwave processing of large volumes. Photocatalytic activity of 200 mL 1 wt% sol after 5 min MW irradiation exhibited enhanced activity than the others.

Mechanism showing titania particle growth in both microwave and conventional heat treatment of sol.Figure optionsDownload as PowerPoint slide