The Controllable Synthesis And Property Research Of Cerous Phosphate Nanomaterials

1-D nanomaterials, such as nanowires, nanotubes, and nanorods, as an important branch of nanomaterials, have attracted much attention these years, due to their special physical properties and potential technological application. Rare earth elements and their compounds, because of the4f electron characters, have many special performances. As a important member of rare earth compounds, cerium phosphate is the research focus in the field of inorganic materials and have widely potential application in the area of fluorescence, ion-exchanger, conductor, and catalysis, and so on.In this study, the effect of reaction conditions on the crystal structure and morphology of Cerium phosphate products in the hydrothermal process has been studied by changing the inorganic cerium source and pH value of the solution. The results indicate that hexagonal CePO4micro-spheres with width of2.1μm and monoclinic monazite CePO4nanowires with diameter of50nm and length of10.5μm can be obtained respectively by using Ce(SO4)2and CeCl3as inorganic cerium source via hydrothermal process. Using CeCl3as inorganic cerium source in the hydrothermal process, monoclinic monazite CePO4nanowires and hexagonal CePO4nanoparticles with relative high surface area can be obtained respectively by adjusting pH value of the solution as1and6.The hexagonal and monazite CePO4nanowires with a narrow range of diameter distribution and large aspect ratio were synthesized mildly through hydrothermal process using inorganic cerium salt and phosphoric acid as reactants in this study. The results indicate that the crystalline phase of CePO4nanowires can be controlled simply by changing the hydrothermal reaction time, that is, the crystalline phase of CePO4nanowires changes from hexagonal to monoclinic monazite while the reaction time increases. Compared with other solution systems, the H2O-EtOH mixed solution is best for the growth of CePO4nanowires. The phase transition of the CePO4nanowires from hexagonal to monoclinic monazite belongs to the displacement phase transition, which would not destroy the structure of CePO4nanowires.Besides, the thermal stability and photoluminescence performance of the as-synthesized CePO4nanomaterials are also studied. The results indicate that with the increase of calcining temperature, the width of CePO4nanowires increases, and the samples remain1-D morphology even after calcined at1000℃, indicating the good thermal stability of the nanowires. With the increase of calcining temperature, the crystalline phase of CePO4micro-spheres changes from hexagonal to monoclinic monazite, accompanied with the appearance of cubic CeO2calcined at900℃. The intensity of UV excited emission in the range of420～550nm decreases shapely while the calcining temperature increases.