Dissertation > Mathematical sciences and chemical > Chemistry > Physical Chemistry ( theoretical chemistry ),chemical physics > Chemical kinetics,catalysis > Catalytic > Catalyst

Synthesis and Visible-Light Photocatalytic Activity of Bi2MO6(M=W, Mo)

Author HanWeiChun
Tutor ZhaoLianHua
School Yanbian University
Course Inorganic Chemistry
Keywords Bismuth layered structure material Hydrothermal method Photocatalytic Oxidation Rhodamine -B Visible light
CLC O643.36
Type Master's thesis
Year 2010
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The photocatalytic oxidation treatment of organic pollutants is a pollution control technology, the rise in recent years, many photocatalyst TiO2 photocatalytic activity, stability, non-toxic, low cost is considered to be the best photocatalyst. TiO2 band gap of 3.2 eV, and therefore can only absorb UV light below 387 nm in ultraviolet sunlight accounts for only about 5%, making solar energy utilization is low. Looking for a higher photocatalytic activity of the catalyst, some scholars sensitized by doping, noble metal deposition and other measures to promote TiO2 absorbance moving to visible light, while the new visible light catalyst was prepared out research. Hydrothermal Preparation of the visible response Bi2WO6 and γ-Bi2Mo08. Material crystal structure, morphology and photophysical properties were characterized by means of XRD, SEM, DRS by degradation of Rhodamine B, according to the change of the absorbance of rhodamine B to evaluate the photocatalytic activity. The main contents can be divided into two parts: 1, bismuth nitrate (Bi (N03) 3.5 H20) and sodium tungstate (Na2WO-2H20) as raw materials, and by controlling the reaction temperature, pH value and the reaction time, etc., conditions, etc., using The hydrothermal method prepare a sample of high purity and good crystallinity Bi2WO6. Its optimum conditions as follows: reaction temperature of 160 ℃, pH = 1.0, reaction time of 24 h. The experimental results show that, the visible type catalyst Bi2W06 of can catalytically effective degradation of rhodamine-B, its catalytic activity is mainly depending on the size of the particle diameter and specific surface area. And adding PVP Bi2WO6 polymorphs changed morphology changed greatly, this is mainly related to surfactant PVP. 2, bismuth nitrate (Bi (NO3) 3-5H2O) and ammonium molybdate ((NH4) 6Mo7024 · 4H20) as raw materials, hydrothermal method to synthesize the the γ-Bi2MoO6 nanocrystalline powder. Experimental results show that under acidic conditions, can also be synthesized γ-Bi2MoO6, and significantly better than the activity of the γ-Bi2MoO6 prepared under acidic conditions obtained in the neutral or weakly alkaline system Bi2MoO6 the activity, and in the strong acid and strong base The samples were prepared under the conditions mixed crystal. Degradation of Rhodamine-B to determine the 140 ° C, pH = 1.0 for hydrothermal the synthesis Bi2MoO6 the best conditions. And prepared in the optimum conditions an Bi2WO6 and under optimum conditions on the preparation of the activity of γ-Bi2MoO6 comparison, visible light-type catalyst γ-Bi2MoO6 forbidden band width smaller than Bi2WO6, but under the same conditions the particle diameter larger than Bi2WO6 ratio surface area to less than Bi2WO6, catalytic degradation of Rhodamine-B, leading to its catalytic activity was weaker than Bi2WO6 this thesis to lay a foundation for the research and application of the match opened up and visible layered perovskite structure of the visible light photocatalyst.

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