BiOCl And Its Compound Photocatalysts:Preparation And Photocatalytic Activity

As a highly anisotropic BiIII-VIA-VIIA ternary layered structure of a semiconductor BiOCl is composed of a tetragonal PbFCl structure and becomes the focus of research due to its unique layered structure and high degradation of organics. So far, Hydrolysis, template,solvent thermal synthesis method and electrospinning method have been used to prepare BiOCl. In this work, BiOCl and its composite photocatalysts were prepared successfully by hydrolyzing bismuth salt. The particle size, phase, morphology, composition and thermal decomposition of BiOCl were characterized by means of Mastersize2000, XRD, SEM,TG-DTG, BET, UV-Vis spectra and XPS. The photocatalytic activity of BiOCl and composites were evaluated by the degradation of MO.The single factor experiments of the hydrolysis process were designed and the influences of adding sequence of reaction solution, mole ratio of reactants, reaction temperature and stirring rate also were investigated. The different morphologies of BiOCl, such as flake, wafer,flower and globular were obtained by optimizing the experimental conditions. Then the micromorphology and photocatalytic performance of BiOCl were studied in detail. The results showed that the spherical bismuth oxychloride crystal had the highest degradation rate of methyl orange at 97.4%.BiOCl/NaBiO₃ and BiOCl/Bi₂O₃ compound photocatalysts with different BiOCl content were prepared by hydrolysis. Photocatalytic property and micromorphology of the compounds obtained were studied. The results showed that BiOCl/NaBiO₃ had the maximum degradation rate of 99.2%, which indicates that compound method is useful to enhance the photocatalytic efficiency. it was found that the surface area rather than the morphology played a decisive role on the catalytic properties.Furthermore, the thermal stability and thermal decomposition behavior of BiOCl were studied for the first time and decomposition behavior about BiOCl were analysized by means of gravimetric analysis. The results showed that the nanometer thin sheet with a thickness of about 70 nm and a cross section of about 300 nm×500 nm could be prepared by hydrolysis method. At 600 ℃ BiOCl started to break down and gradually break down into BixCly,BixOyClz, Bi₂O₃, and Bi3O4 Cl obtained finally at 800 ℃.