Microemulsion-mediated solvothermal synthesis and photocatalytic properties of crystalline titania with controllable phases of anatase and rutile.

Titanium oxide with different ratios of anatase to rutile has been prepared by the microemulsion-mediated solvothermal method. The resulting samples were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, UV-vis diffuse reflectance spectra, transmission electron microscopy and Brunauer-Emmett-Teller analysis. The contents of anatase and rutile in the TiO(2) particles have been successfully controlled by simply adjusting the amount of urea in the aqueous phase of the microemulsion. Both the degradation of Rhodamine B in aqueous solutions and mineralization of TOC revealed that the catalyst containing 47.6% anatase have presented the highest photocatalytic activity. A proposed mechanism is discussed to interpret the evolution of the phases based on the effect of different amount of urea.