Synthesis And Photocatalytic Degradation Properties Of Tetracycline Hydrochloride From Gallium/Antimony-based Oxide Compounds

The control of environmental pollution attracted widespread concern of the world.The semiconductor photocatalytic technology plays an important role in the degradation of environmental pollutants,due to the mild reaction conditions,no secondary pollution and the use of natural sun light.However,the TiO₂^-based photocatalysts have some drawbacks,such as the low quantum efficiency and become inactivated during the degradation of refractory organic pollutants,which restricted their applications.Developing of high efficient catalysts have become a research focus of photocatalysis.The p-block metal oxide and composite oxide is widely studied as a new photocatalyst.In this paper,p-block metal Ga and Sb oxide and composite oxide（Ga₂0₃,Sb₂0₃,ZnGa₂0₄,ZnSb2O6 and ZnGa₂0₄）were prepared and the photocatalytic degradation of tetracycline hydrochloride were studied.The photocatalyst was characterized by X-ray powder diffraction,scanning electron microscopy,UV-Vis diffuse reflectance spectroscopy,fourier infrared spectroscopy,electrochemical test and N2 adsorption.The main conclusions are as follows:（1）The Ga₂0₃ samples were prepared by hydrothermal,sol-gel and precipitation methods,and the products prepared by different synthetic methods show great difference in photocatalytic performance.The Ga₂0₃ samples obtained by precipitation method had the best effect of degradation of tetracycline hydrochloride under ultraviolet light.The Sb₂0₃ photocatalyst synthesized by precipitation method can degraded tetracycline hydrochloride under UV light as well,but the activity was much lower than that of Ga₂0₃ prepared by the same method.（2）Without the influence of the synthesis method,the energy band structure,crystal structure and hydroxyl groups in the surface of the catalyst are the main reasons for the difference in the photodegradation performance of Ga₂0₃ and Sb₂0₃ samples.While the specific surface area,crystallinity and crystal internal defects have no direct relationships with the difference in photocatalytic performance of these two catalysts.All of the hole,O₂^-·and·OH work in the photocatalytic degradation of tetracycline hydrochloride,while O2’·is the main active species;However,hole and·OH show synergistic effect when Sb₂0₃ photodegrades tetracycline hydrochloride.（3）The ZnGa₂0₄ samples were synthesized by hydrothermal and coprecipitation methods.The different methods of synthesis had great influence on the photocatalytic activity of the samples.The ZnSb2O6 and ZnGa₂0₄ photocatalyst synthesized by hydrothermal method can degraded tetracycline hydrochloride under UV light as well,but the activity was much lower than that of ZnGa₂0₄ prepared by the same method（4）Without the influence of the synthesis method,the energy band structure and crystal internal defects of the catalyst are the main reasons for the difference in the photodegradation performance of ZnGa₂0₄,ZnSb2O6 and ZnGa₂0₄ samples.While the energy band structure,crystal structure and hydroxyl groups in the surface of the catalyst cause no effect.O₂^-·is the main species when ZnGa₂0₄ photodegrading tetracycline hydrochloride.All of the hole,OI2-·and·OH work in the photocatalytic degradation of tetracycline hydrochloride over ZnSb2O6 and ZnGa₂0₄,while·OH is the main active species in the photodegradation process over ZnSb2o6;and o2-·is the main active species in the photodegradation process over ZnGa₂0₄.