Morphology Control And Photocatalytic Properties Of Tungsten Oxide And Lanthanum Bromide Micro-nano Materials

Metal oxide micro-nano materials,such as ZnO,CuO,Ag2O,SnO2,WO3,Cu2O and so on,show excellent photoelectric conversion characteristics.BiOBr is a V-VI-VII ternary semiconductor.It is a new kind of micro-nano materials.They are very promising materials in the field of photoelectronics.In this dissertation,by using different methods,raw materials and surfactants,novel BiOBr and WO3 nanomaterials were prepared by using BiOBr and WO3 nanomaterials as the research object.Their photocatalytic properties were also tested.The main contents of this thesis include the following aspects:(1)3D hierarchical WO3·0.33H2O microspheres have been successfully synthesized by one-pot solvothermal method at the temperature of 160?.The hierarchical WO3·0.33H2O microspheres are composed of many slices with jagged edges,with side length of 100?300 nm and a thickness of about 50 nm.K2SO4,as a directing agent,plays an important role in controlling the morphology of WO3·0.33H2O samples.In addition,a series of time-depended tests have been listed,by which we can obtain the morphological evolution of hierarchical WO3·0.33H2O microspheres.Moreover,the products exhibit excellent photocatalytic activity for the photodegradation of Rhodamine B(RhB)under visible light irradiation.(2)The hollow hierarchical BiOBr microspheres with the diameter of about 1?m,which are composed of curved sheets,are synthesized by a solvothermal method in the presence of 0.1 g of SDS and the Bi/Br ratio of 0.7:0.7 at 160 ? for 12 h.A series of time-depended tests have been listed,by which we can obtain the morphological evolution of hollow hierarchical BiOBr crystal structure.SDS,as an ionic surfactant sodium dodecyl sulfate,plays an important role in controlling the morphology of BiOBr samples.The morphologies of BiOBr samples with adding different amounts of SDS in solution and different ratio of Bi/Br are compared.The obtained BiOBr hollow structures exhibit higher photocatalytic activity towards the degradation of Rhodamine B(RhB)and Methylene blue(MB)under visible-light irradiation,up to 98.6%and 95.3%within 24 min respectively.(3)Novel 3D coralline-like BiOBr architecture with a diameter of 500?600 nm which is assembled by curved slices,has been successfully synthesized by one-pot solvothermal method.In this work,PVP and Bi(NO)3·5H2O are used as surfactant andBi source,respectively.A series of time-depended tests have been listed,by which the morphological evolution of 3D coralline-like BiOBr crystal structure is obtained.PVP,which is acted as surfactant,plays an important role in controlling the morphology of BiOBr samples.The morphologies of BiOBr samples with different amounts of PVP in precursor solution have been compared.Moreover,the obtained products show excellent photocatalytic activity towards the degradation of MB under visible-light irradiation.Up to 98.8%MB in solution is degraded by BiOBr within 30 min.