General Synthesis and Optical Properties of Monodisperse Multifunctional Metal-Ion-Doped TiO2 Hollow Particles

Various, monodisperse, multifunctional metal-ion-doped TiO 2 hollow particles are prepared by a general metal-ion-doped method. They show brilliant colors in the visible region and low reflectance in the ultraviolet range. For example, the reflectances of green Co-doped TiO 2, red Fe-doped TiO 2, green Co/Zn-doped TiO 2, and sky blue Co/Al-doped TiO 2 particles are 5.9, 4.8, 5.9, and 4.8%, respectively, and the infrared emissivities in the region of 8−14 μm are very high, 97.5, 93.7, 95.2, and 96.9%, respectively. These results show that the monodisperse hollow particles could be potential candidates as good pigments, ultraviolet prevention materials, and thermal conservation materials. In addition, Al-doped TiO 2 and Al/Fe-doped TiO 2 particles are also prepared by this strategy.