The Construction Of Biox (X= Cl, Br) Nanosheet Composite Film And Its Photocatalytic Properties Study

This paper reported the preparation of the BiOX (X= Cl, Br) two-dimensional nanosheet by hydrothermal and the delamination by precipitation process, and the electrostatic assembly with colloidal AuNP to achieve BiO(X)/AuNP composite film. The morphology, structure and properties of these composite films were characterized by SEM, small-angle XRD, UV-visible absorption spectrum, fluorescence spectrum and so on. It was found that these assembly composite films had uniform surface with a layered ordered structure, and the UV absorption intensity of these films increased linearly with increasing the number of assembly layers, which illustrated the assembly process is regular and the thickness of each layer is uniform. Under light irradiation, it can be achieved effective electrons transfer between BiO(X) and AuNP, therefor this composite film can be applied in the photocatalytic degradation of methyl orange. This work demonstrated the good photocatalytic activity of the BiO(X)/AuNP composite film by experiment, and concluded as follows:1. The property of the obtained film is different with the concentration of AuNP solution during the assembly process, when the concentration is 6.6×10-4mol/L, the photocatalytic degradation is best and AuNP disperses uniformly in the film, which is in favor of its optical property.2. Compared with the pure BiOCl or BiOBr, the (BiO(X)/AuNP)20 composite film showed prominent photocatalytic activity under light illumination, after 50 minutes, the methyl orange solution was almost completely degraded. This is attributed to the presence of AuNP in the the film which accelerate the separation of the photo-generated electrons and holes, thus it improved the photocatalytic activity.3. Compared with BiO(Cl)/AuNP, BiO(Br)/AuNP assembly film showed better degradation effect for methyl orange, which is due to the visible and ultraviolet regions absorbance intensity of BiOBr are higher than BiOCl. Finally, some organic molecules, such as anionic polymers-PSS and PAAS, a small molecule-CXT (fluorescent whitening agent), were selected to assembled with BiO(Cl) colloidal solution, the results show that these organic molecules can also successfully assemble with BiO(Cl) colloidal solution to formed ordered composite films, which proved the applicability for constructing composite film and benefit the development and wide application of the BiOCl.