Synthesis, Characterization And Study On Photocatalytic Property For Molybdate Nanomaterials

Molybdate nanomaterials with superior optical, electrical and magnetic properties have broad application prospects. So it is very important to study the controlled synthesis of nanoscale materials for molybdate, to explore the relationship between the molybdate nature and properties of its size morphology, development of new fields of application of molybdate. It becomes one of the hotspots of the Materials Research. In this thesis, the Synthesis, characterization and study on photocatalytic property for molybdate nanomaterials were investigated. Flake-like and nanoparticles y-Bi2MoO6were prepared by a hydrothermal method using citric acid as the capping agent. A possible formation mechanism of the flake-like and nanoparticles y-Bi2MoO6was proposed. Two kinds of bismuth molybdates: a-Bi2Mo3O12andy-Bi2MoO6were prepared by co-precipitation method. By tuning pH values and calcining at400℃, controlled formation of bismuth molybdates can be achieved. A possible mechanism on the formation of bismuth molybdates was proposed in details. Fe2(MoOO4)3powders and SrMoO4powders with different morphologies were prepared via microemulsion methods. The effect of process parameters on the morphology of the SrMoO4products was investigated. On this basis, their photocatalytic decolorization and photochromic properties were investigated.The details are summarized as follows:1. Hydrothermal Synthesis and Photocatalytic properties of flake-like and y-Bi2MoO6nanoparticlesFlake-like and nanoparticles y-Bi2MoO6were prepared by a hydrothermal method using citric acid as the capping agent. The obtained products were characterized by X-ray diffraction, scanning electron microscopy, and UV-vis diffuse reflectance spectroscopy. A possible formation mechanism of the flake-like and nanoparticles Y-Bi2MOO6was proposed. Photocatalytic experiments showed that flake-likey-Bi2MoO6exhibited good photocatalytic activities for degradation of crystal violet solution under sunlight irradiation.2. Synthesis of a-Bi2Mo3O12by co-precipitation method and photocatalytic activityTwo kinds of bismuth molybdates:a-Bi2Mo3O12andy-Bi2MoO6were prepared by co-precipitation method. By tuning pH values and calcining at400℃, controlled formation of bismuth molybdates can be achieved. When nBi/nMo=1:2, low pH value (pH=3and5) lead to the formation of a-Bi2Mo3O12and pH=7lead to the formation of (3-Bi2Mo2O9and y-Bi2MoO6. High pH value (pH=9) favor the formation of Y-Bi2MoO6. Furthermore, a possible mechanism on the formation of bismuth molybdates was proposed. Photocatalytic studies indicated that Y-B12MOO6showed more intense absorption band in the visible light region and better photocatalytic activity than a-Bi2Mo3O12under sunlight irradiation. The effect of factors on photocatalytic activities for two kinds of photocatalysts was also discussed.3. Synthesis of Fe2(MoO4)3Feton-like Catalyst and Degradation of Crystal Violet at Neutral ConditionThe pure Fe2(MoO4)3catalyst were successfully synthesized via microemulsion method. The characterization of the product was measured by TG、 XRD and SEM. Degradation of crystal violet solution at different pH value conditions was studied using Fe2(MoO4)3as catalyst. The result showed that the degradation ratio of crystal violet solution reached91.00%at neutral condition. Moreover, the catalytic activity was slightly affected by the solution pH in a wide range of3.0-9.0. At the same time, the possible reaction mechanism was proposed in detail.4、 Preparation of SrMoO4Material with Different Morphologies via Microemulsion Methods SrMoO4powders with different morphologies were prepared via microemulsion methods. The effect of process parameters on the morphology of the SrMoO4products was investigated. The results showed that CTAB content, reactant concentration and the reaction time in the microemulsion system had great influence on the morphology of the SrMoO4products. The strong single violet emission centering at about420nm was observed in the room temperature PL spectra of the SrMoO4samples. The luminous intensity and peak position were different for the samples with different morphologies.