Preparation and properties of zinc oxide nanoparticles coated with zinc aluminate

Zinc oxide nanoparticles coated with zinc aluminate were prepared by precipitation of Al2O3 on the ZnO precursor, basic carbonate of zinc (BCZ). TEM showed that a homogeneous layer is formed on the surface of the ZnO nanoparticles, and the coated particle size is about 50-60 nm. The layer thickness estimated by high magnification TEM is about 4-5 nm. XPS showed that the elements in the coating at the surface of the ZnO nanoparticles are Zn, O and Al. XRD and lattice fringe data show that the coating is of the ZnAl2O4 phase formed by the reaction of basic carbonate of zinc and basic carbonate of aluminium. The zinc aluminate coating is effective in reducing the catalytic activity of ZnO nanoparticles. ZnO nanoparticles coated with zinc aluminate not only retain a high UV absorptivity, but also increase their reflectance of visible light. 21 refs.