| With the development of society,energy and the environment has become the two major problems facing mankind.Photocatalytic technology is efficient,no secondary pollution,which has aroused widespread concern,the photocatalytic response to visible light has become a hot spot.Typical alkaline dye RhB can increase the color of water,resulting in visual pollution,and has carcinogenic,the water environment and the human body will cause serious harm.In this paper,Ag/AgCI/ZnBi2O4 was characterized by the photocatalytic activity and mechanism of the new visible light photocatalyst Ag/AgCl/ZnBi2O4.The photocatalytic activity and its reaction mechanism were studied.The main contents and conclusions of this paper are as follows:Firstly,a new visible light photocatalyst Ag/AgCl/ZnBi2O4 was synthesized by hydrothermal synthesis.SEM,EDX,XRD,UV-Vis and XPS were used to characterize the surface morphology and composition elements,crystal size and phase structure,light absorption properties and main chemical composition.The results of SEM showed that the growth of cube-like Ag/AgCl was on the surface of mosaic ZnBi2O4.The XRD patterns show that Ag/AgCl/ZnBi2O4 posseses the good crystal morphology and the high crystallinity.The results of UV-Vis showed that the adsorption of Ag/AgCl/ZnBi2O4 on the visible light was the same as that of ZnBi2O4,and the band gap was narrowed.The results of EDX and XPS show that the catalyst contains Zn,O,Bi,Cl and Ag elements,indicating that the synthesized photocatalyst Ag/AgCl/ZnBi2O4 is pure.The results of XPS showed that the O element is mainly in the form of O2-,the Zn element is mainly in the form of Zn2+,the main chemical valence of the Cl element is-1,the main chemical valence of the Bi element is +4,and the Ag element has two forms:Ag element and Ag+.Secondly,photocatalytic experimental results show that under visible light irradiation,when Rhodamine B concentration was 2mg/L,the best dosage of Ag/AgCl/ZnBi2O4 was 0.07g,the degradation rate of Rhodamine B reached 89%;The best reaction condition is Rhodamine B concentration was 1 mg/L,pH=3,the dosage of Ag/AgCl/ZnBi2O4 is 0.07g.The best reaction condition of ZnBi2O4 was that the initial concentration of Rhodamine B was 2mg/L,the dosage of ZnBi2O4 was 0.07g.The reactions of ZnBi2O4,Ag/ZnBi2O4 and Ag/AgCl/ZnBi2O4 were consistent with the pseudo-first order kinetic model.The reaction rates of degradation of Rhodamine B were 0.0141,0.0117 and 0.0120min-1,respectively.The photocatalyst Ag/AgCl/ZnBi2O4 has the good stability.Finally,the free radical capture experiments show that ·O2-free radicals are the main active substances in the photocatalytic degradation of Ag/AgCl/ZnBi2O4 and play a key role in the reaction process.In this paper,the Z photocatalytic reaction mechanism of Ag/AgCl/ZnBi2O4 was proposed according to the results of free radical capture experiments,electrochemical experiments and Ag/AgCl/ZnBi2O4 self band structure. |
