Preparation Of Doped Bismuth Oxychloride And Enhancement Mechanism Of Photocatalytic Degradation Of Dyes

As a typical layered ternary oxide semiconductor,bismuth oxychloride(BiOC1)has received considerable attention for its potential application in pollutant control,hydrogen production by water splitting,CO2 photoreduction and N2 fixation.In the lattice,the layered structures,characterized by[Bi2O2]2+layer sandwiched between two slabs of halogen layers,offer an internal electric field perpendicular to[Bi2O2]2+and[Cl2]2-layers,thus facilitating the separation and transfer of photogenerated carries.Unfortunately,pristine BiOCl still suffers from the low efficiency of visible-light utilization and high recombination rate of photogenerated excitons,which restricts its photocatalytic efficiency.Therefore,in this paper,one-pot solvent thermal method was used to modify the BiOCl,the nickel doped BiOCl(marked as Ni-BiOCl)and tantalum doped BiOCl nanosheets coupling with bismuth nanodots(named as Ta-BiOCl/Bi)were successfully constructed,which can realize the band structure adjustment and excellent photocatalytic performance of the modified BiOCl.(1)In this chapter,one-pot solvothermal method was used to realize the Ni doping and morphology control of BiOCl.When the molar ratio of Ni2+to Bi3+is 1:2,the solvent is glycerin,and the reaction temperature is 160℃,the Ni-BiOCl semiconductor has a flower like morphology composed of fine nanoflakes.With the in fluence of doping and morphology control,the reactive site center,specific surface area and carriers’ lifetime have been significant increased.Meanwhile,the energy band structure is optimized after modifying.The photocatalytic activity of Ni-BiOCl in visible light is 13.1 times of that before doping,the kinetic constant is 1.140 min-1,and the product shows excellent cycling stability.Based on the above，19 kinds of metal ion doped BiOCl(named as M-BiOCl)can be prepared in this work.(2)Tantalum(Ta)doped BiOCl nanosheets coupling with bismuth(Bi)nanodots(Ta-BiOCl/Bi)have been constructed successfully by solvothermal method in this paper,implementing Ta doping and Bi nanodots coupling simultaneously.When the molar ratio of Ta5+to Bi3+is 1:5,the solvent is glycol,and the reaction temperature is 160℃,Ta-BiOCl/Bi exhibits excellent visible light degradation performance due to the integration of doping as well as loading,which results in a rough surface morphology,rich reactive sites,multiple electron transfer channels,high efficiency of photogenerated carrier separation and transport and optimized energy band structure.In addition,Ta-BiOCl/Bi displays good adsorption and visible light degradation properties of Rhodamine B,rhodamine 6G,methylene blue,methyl orange,crystal violet and malachite green.The kinetic constant of degradation of RhB by Ta-BiOCl/Bi under visible light irradiation is 2.196 min-1,which is 62.7 times higher than that of pure BiOCl under the same preparation conditions.