Preparation and visible-light photocatalytic activity of ag-loaded TiO2@Y2O3 hollow microspheres with double-shell structure

Using melamine-formaldehyde as template, tetrabutyl titanate as titanium source, and ytterbium nitrate as ytterbium source, the Ag-loaded double-shell TiO2@Y2O3 hollow microspheres with TiO2 as inner layer and Y2O3 as outer layer were prepared by sol-gel method and high-temperature calcinations reduction. The characterization of hollow microspheres shows that the Ag-loaded TiO2@Y2O3 hollow microspheres show regular morphology, uniform size and distinct double-shell hollow structure. Ag exists as the zero-valent form in the double-shell hollows spheres mainly. The results of Uv-visible diffuse reflection analysis and photocatalytic testing under visible-light show that the forbidden band widths narrowed and the photocatalytic activities improved significantly after the load of Ag. Moreover, the location of loaded-Ag has great effect on the photocatalytic activity of TiO2@Y2O3 hollow microspheres. Compared with Ag located on the surface of the hollow microspheres, Ag located between the two shells of the hollow microspheres improved their photocatalytic activity more effectively. (C) 2020 Elsevier B.V. All rights reserved.