Surfactant effect on controllable phase transformation and UV-shielding performance of titanium dioxide

Abstract

The crystalline structure, size and morphology of TiO2 have crucial influence on its physicochemical performance. The crystal growth process includes crystal transformation and morphology evolution, which is closely related to the solution environment. In this work, rutile TiO2 was synthesized via surfactant-assisted method by using titanium sulfate as titanium source. Factor associated with crystalline structure of TiO2 were investigated including surfactant type and concentration. Results showed that when the concentration of cetyltriethylammonium bromide (CTMAB) was greater than or equal to 3 mmol/L, or the concentration of dodecyltriethylammonium bromide (1231) was greater than or equal to 4 mmol/L, surfactants promoted transformation from anatase to rutile titania. The UV-shielding performance of the surfactant-aided titania increased, and the band gap width decreased by 0.2–0.3 eV. More importantly, we found that the cationic surfactant played a decisive role in anatase-rutile transformation of titania. The microspherical cationic surfactant micelles were chelated by electrostatic adsorption and [TiO6] octahedron, and the [TiO6] octahedron tended to grow to the opposite side, which was formed to form rutile titania.