Preparation Of The Modified Nano-TiO₂ Composite Photocatalyst And Research The Visible-light Photocatalytic Property

In the past decades,a large number of semiconductor-based photocatalysts,such as TiO2,ZnO,SnO2,SiO2,CdS,PbS,g-C3N4,and MO2O3,have received great attention in the field of the environmental protection.Among the various semiconductors,TiO2 is one of the most prospective photocatalysts due to its non-toxicity,large availability,long-term chemical stability,strong oxidizing power and high efficiency of photoactivity.However,because of the wide energy gap,TiO2 will exhibit high efficiency of photocatalytic activity only under UV irradiation.Furthermore,the practical applications of TiO2 are also restricted by its low efficiency of electron-hole separation.Thus tremendous research efforts have gone into reducing the band gap of TiO2 to enhance its photocatalytic performance with activation in visible region of electromagnetic spectrum.The modification of TiO2 was studied in this paper,TiO2-XNX were prepared by the hydrolysis of TiCl4 and NH3-H2O microwave calcination.The composite materials Ag3PO4/TiO2-xNx,Ag/AgCl/TiO2-xNx and RGO/TiO2 were obtained by chemical precipitation and the visible-light photocatalytic properties of the catalysts were researched.(1)The TiO2-xNx nanoparticles have unique rod-like structure,so the Ag3PO4 nanoparticles can distribute on the surface of the TiO2-xNx nanoparticles to form the heterostructure by a chemical precipitation method.Owing to the Ag3PO4/TiO2-xNx heterostructure has smaller size and more active sites which has larger specific surface area and better photocatalytic activity than pure Ag3PO4.The as-prepared Ag3PO4/TiO2-xNx heterostructure was employed to degrade methyl orange and to inactivate E.coli under visible light irradiation,which exhibited high photocatalytic activity,could degrade 95.5%of MO(λ(?)500nm)and kill almost 99.86%of the E.coli(λ(?)400nm)in an hour.(2)The Ag/AgCl nanoparticles were doped on the surface of the TiO2-xNx to form the Ag/AgCl/TiO2-xNx composite by a pyrogenic decomposition method.Compared with the pure TiO2-xNx,the absorption wavelength of Ag/AgCl/TiO2-xNx composite can extend to visible-light absorption range of the photocatalysts and promote the separation efficiency of photo-generated electron-hole pairs.The Ag/AgCI/TiO2-xNx composite photocatalysts were characterized by XRD,DRS,XPS,SEM and TEM.All the analysis demonstrated that the Ag/AgCl nanoparticles which distributed on the surface of TiO2-xNx could enhance the visible-light photocatalytic activity obviously of the Ag/AgCI/TiO2-xNx composite materials.(3)Graphene oxide(GO)were prepared by the method of Hummers and the Hydro-thermal method was adopted to prepared the RGO/TiO2 composite photocatalyst.The RGO/TiO2 material was characterized by XRD,FT-IR and SEM.The photocatalytic activities of the photocatalyst was tested by the degradation of methyl-orange under the visible light.The result demonstrated that the RGO/TiO2 composite materials has high efficiency of photocatalytic activities under the visible light irradiation.