Low temperature synthesis and characterization of rutile TiO2-coated mica–titania pigments

Rutile TiO2-coated mica–titania pigments were prepared by hydrolysis of TiCl4 ethanolic solution in water at 70 °C. MnO2 as a rutile promoting additive was deposited onto mica prior to TiO2. X-ray diffraction and Raman spectra analysis verified that use of only 2.07 wt% MnO2 with respect to mica weight began to provide a complete rutile TiO2 coating without calcination. The rutile promoting effects of MnO2 could be ascribed to the structural similarity of rutile and pyrolusite. Scanning electron microscopy analysis showed that MnO2 also had a pronounced effect on the morphology of TiO2 coatings. The prior deposition of MnO2 onto mica lead to the formation of rutile TiO2 films composed of highly oriented fine needles on the mica surface and nanoflower structures on the needle structures. The as-obtained rutile-TiO2 coated mica–titanium pigments are shown to exhibit a high photostability under UV illumination.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Rutile TiO2-coated mica–titania pigments were prepared at 70 °C. ► MnO2 as a rutile promoting additive was deposited onto mica prior to TiO2. ► Rutile TiO2 films were composed of fine needles and nanoflower structures. ► Rutile-TiO2 coated mica–titanium pigments exhibit a high photostability.