Study On The Preparation And Photocatalysis Properties Of Nano-ZnO And Silver Series Composite Materials

The use of organic pollutants in light of nanocatalytic techniques of degradation has become a effective way to research in the field of environmental protection)with photocatalytic properties of nano-materials, nano-Zn O as a direct bandgap semiconductors for the advantages of highly efficient quantum yield, photocarriers carriers can be effectively separated, cheap and easily preparation growing much attention. However, But the large gap energy of Zn O exhibits only ultraviolet absorption characteristics can not absorb the longer wavelengths of visible light. Therefore it's a hotspot to broaden the scope of Zn O light response and realize the photogenerated electrons and holes effectively to enhance the photocatalytic properties of Zn O in photocatalysis.In this paper, zinc acetate as zinc source, the structure of nano-Zn O of rod, cap-like hexagonal and flake was prepared by hydrothermal method with the alkali source of ammonia,hexamethylene tetramine, sodium hydroxide respectively. Heterostructu-red Ag2O/Zn O composite photocatalyst was made via a hydro-thermal synthesis with Zn(NO3)2, Ag NO3, C6H12N4 and PVP-K30. Ag3PO4/Zn O composite photocatalytic material was prepared via coprecipitation method by depositing Ag3PO4 nanoparticles onto the surface of Zn O microspheres. The obtained samples were tested and characterized by XRD?SEM?EDX and UV-Vis, the photocatalytic degradation of Rh B with the synthesized photocatalyst was investigated under different light irradiation.The influence of the morphological features and the amount of silver homologue loading on the photocatalytic activity of the photocatalyst was investigated. The reasons for the promotion of photocatalytic activity, the photocatalytic reaction mechanism and the optimal amount of photocatalyst needed for the degradation of Rh B solution were also explored.The research achievement shows that:(1) The photocatalytic activities of rod nano-Zn O and cap-like hexagonal nano-Zn O prepared was stronger than flake nano-Zn O. Because the ratio surface of two former samples as-prepared is greater than flake nano-Zn O that can absorb more dye molecular. The optimal dosage of simple as-prepared on photocatalytic degradation of 5mg/L Rh B solution separately was 20 mg, 20 mg and 30 mg.(2) Ag2O/Zn O composite photocatalyst as-prepared exhibit significant absorption characteristics in the visible region,which possess high catalytic activity both in the ultraviolet or visible light irradiation.As the two matches to achieve the energy band structure of photo-generated carriers efficient separation, thereby increasing photocatalytic activity of the composite material, the optimum ratio of Ag2 O doping with Zn O is 8at%, The optimal dosage of 8at%Ag2O/Zn O simple as-prepared on photocatalytic degradation of 5mg/L Rh B solution under ultraviolet and visible light irradiation both were 20 mg.(3)Ag3PO4/Zn O Composite material as-prepared appear redshift range of light response, which showed a strong optical absorption capacity at 450nm-800 nm. Since the composite heterostructures led light electrons and holes to be effectively separated, to further enhance the photocatalytic properties of the composites. The optimum ratio of Ag3PO4 doping with Zn O is 6at%, The optimal dosage of 6at% Ag3PO4/Zn O simple as-prepared on photocatalytic degradation of 5mg/L Rh B solution under ultraviolet and visible light irradiation both were 30mg.