The Controllable Synthesis And Modification Research Of BiOCl Nanosheet With Exposing {001} Facets

Semiconductor photocatalytic materials can directly use the energy of sunlight to degradation of organic pollutants in the environment. With advantages of high efficiency, energy saving and no secondary pollution, it has been widely used in environmental purification, disinfection, sterilization, medical and health, and many other aspects, which shows great potential and long-life. As a new photocatalytic material, BiOCl exhibit excellent photocatalytic activity due to its unique layered structure and build-in electric field, which is binifit for the separation of photo-induced carrier, and attract much attention. However, Bi OCl is indirect semiconductor material with the band gap of 3.4 eV, so it can only be activated by the UV light below 360 nm, which only account for about 3% of solar energy and greatly limits the practical application of BiOCl. Hence, it is urgent to expand the light response of the BiOCl for improving the photocatalytic performance. Recent studies have shown that the photocatalytic performance of the Bi OCl is closely related to crystal orientation, especially the regulation of highly active {001} facets have become the focus of the current. So the synthesis of the BiOCl with adjustable facets, and then expand the visible light respond to improve the photpcatalytic efficiency of BiOCl should be significant for improving its practical application value.This dissertation reported the controllable synthesis of Bi OCl with exposing {001} facets, and then the BiOCl was modified via halogen ions doped, metal ions doped, and electron beam irradiation. Details are as follows:(1) The BiOCl samples with different rate of {001} facets were obtained via adjusting the preparation temperature. Then the crystal structure, microstructure, the performance of light absorption and photocatalytic performance were characterized. Results show that with the improvement of temperature, BiOCl tend to grow in the direction of [110], which leads to the increase of gain size and the ratio of {001} facets and decrease of thickness. In addition, the temperature rise can result in a sharp increase of the specific surface area, which causes the decrease of photocatalytic performance.(2) The BiOCl1-xBrx and BiOCl1-yIy were obtained via the treatment of BiOCl using halogen ion solution, which improved the absorption of visible light and photocatalytic efficiency of BiOCl. Form the point of solubility product, we further studied the alternative rule of halogen ions in BiOCl. Then BiOCl of different colors were obtained via metal ion doping(silver, copper, iron), which showed different response to visible light while the photocatalytic activity was not signifaicantly improved.(3)The metal Bi loaded BiOCl obtained via electron beam irradiation. The structure evolution of BiOCl and the precipitation rule of metal Bi was studed with HRTEM. Then the crystalline fluctuation and growth mechanism of Bi nanoparticles were studied.