The investigation of Ag decorated double-wall hollow TiO2 spheres as photocatalyst

In this paper, a novel TiO2 nanosheets assembled double-wall hollow sphere (DHS)has been prepared successfully via hydrothermal treatment of SiO2@TiO2 with the assistant of CTAB.The prepared samples are characterized with transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron spin resonance (ESR), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS), etc.Results show that redeposited silica species play a key role in the formation of the double-wall structure. The as-synthesized DHS nanostructure exhibits a large surface area (417.6 m(2) g(-1)) and excellent mechanical strength. Furthermore, after decoration of Ag and calcination treatment, the double-shelled TiO2/Ag heterostructures show an enhanced photocatalytic performance in the degradation of RhB under UV or visible light irradiations for the following reasons: the surface plasmon resonance effect of Ag, strong interaction between Ag and TiO2 nanosheets, large surface area, excellent adsorption capacityand unique double-wall structure. On the basis of the experimental results, a possible mechanism for pollutantdegradation under visual light irradiation has been proposed.