Preparation and visible-light photocatalytic properties of the floating hollow glass microspheres - TiO/AgPO composites.

A novel floating visible-light photocatalyst (HGMs-TiO/AgPO) composite was prepared using amino modified low-density hollow glass microspheres (HGMs) as carriers to disperse and support TiO and AgPO photocatalysts. The surface morphology, crystal structure and optical properties of the HGMs-TiO/AgPO composites were characterized and the AgPO 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/AgPO composites. For HGM composite photocatalysts, when the theoretical mass ratio of TiO to AgPO on the surface of HGMs is 1 : 1.5, the visible-light catalytic activity of the composite is superior to pure AgPO and a TiO/AgPO 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 and AgPO particles can be well dispersed on the surface of the floating HGMs. Furthermore, the deposits of TiO and AgPO 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 AgPO. This work indicates that floating HGMs-TiO/AgPO composites could become a promising photocatalyst for organic dye removal due to the low cost and high visible-light responsiveness.