Preparation and visible-light photocatalytic properties of the floating hollow glass microspheres - TiO 2 /Ag 3 PO 4 composites.

A novel floating visible-light photocatalyst (HGMs-TiO 2 /Ag 3 PO 4 ) composite was prepared using amino modified low-density hollow glass microspheres (HGMs) as carriers to disperse and support TiO 2 and Ag 3 PO 4 photocatalysts. The surface morphology, crystal structure and optical properties of the HGMs-TiO 2 /Ag 3 PO 4 composites were characterized and the Ag 3 PO 4 content on the surface of the microspheres was determined by atomic absorption spectrometry (AAS). Methylene blue (MB) was chose as the organic pollutant to investigate the visible-light catalytic properties of the HGMs-TiO 2 /Ag 3 PO 4 composites. For HGM composite photocatalysts, when the theoretical mass ratio of TiO 2 to Ag 3 PO 4 on the surface of HGMs is 1 : 1.5, the visible-light catalytic activity of the composite is superior to pure Ag 3 PO 4 and a TiO 2 /Ag 3 PO 4 photocatalyst with a mass ratio of 1 : 1.5 under the same conditions, due to the increased light-contact area and the photocatalytic active sites, since the TiO 2 and Ag 3 PO 4 particles can be well dispersed on the surface of the floating HGMs. Furthermore, the deposits of TiO 2 and Ag 3 PO 4 on the HGM surface form a heterostructure, facilitating the separation of electron-hole (e - - h + ) in the energy band, and elevating the photocatalytic activity and cycle stability of Ag 3 PO 4 . This work indicates that floating HGMs-TiO 2 /Ag 3 PO 4 composites could become a promising photocatalyst for organic dye removal due to the low cost and high visible-light responsiveness.