Solid-state Chemical Synthesis And Photocatalytic Properties Of Bismuth Oxide Halides Nanomaterials

Semiconductor photocatalytic technology is a high-efficiency and environmental-friendly method, which attracted widespread attention by chemists,physicists and materials scientists. The organic pollutants can be directly decomposed into CO2, H2 O and other small inorganic molecules by semiconductor photocatalyst.At present, the research of photocatalytic materials mainly focus on the modification of TiO2 or other traditional photocatalyst and the development of new semiconductor photocatalysts. As a novel semiconductor photocatalyst, bismuth oxide based photocatalyst has become the hot topic in the semiconductor photocatalyst field,which own to its excellent visible light photocatalytic activity and the layered structure. This article is mainly study the preparation, modification and the properties of several bismuth oxide halides. The main research contents of this thesis are as follows.(1) The BiOX(X=Cl, Br, I) nanoplates and microspheres were synthesized by a rapid and simple room-temperature solid-state reaction. The phase, morphology,specific surface area and optical properties of the samples were characterized by XRD,SEM, HRTEM, BET and UV~Vis, respectively. The photocatalytic tests show that the Bi OCl microspheres displayed much higher photocatalytic activity than BiOCl nanoplates in the degradation of RhB under the UV or visible light. This mainly attributed to the large specific surface area of BiCl microspheres, which is beneficial to the adsorption and transport of dye molecules. In addition, the degradation efficiency of BiOX microspheres for RhB under visible light was followed by Bi OCl>BiOBr>BiOI.(2) The BiOClxI1-x solid solutions were also synthesized by the room-temperature solid-state reaction, the morphology of all the samples are microspheres which were assembled by nanoplates. The specific surface area and the width of band gap ofBi OCl0.75I0.25 solid solutions are 51.17 m2/g and 2.96 eV, respectively. The photocatalytic reaction was carried out under visible light for degradation of RhB, the degradation rate was 96% after the reaction for 120 min.(3) The Bi24O31X10(X=Cl, Br) and BiOX/Bi24O31X10 heterostructure materials have been prepared by a two-step solid-state method. The results showed that Bi OX/Bi24O31X10 heterojunction materials have smaller particle size and excellent visible light photocatalytic performance for degragation of RhB, which is mainly due to the accelerate transfer rate of the photoinduced electron at the heterojunction interface, thus the photoinduced electrons and holes are separated more efficiently,and then increase the photocatalytic activity.