【作者】 靳莉；

【导师】 江汝元；

【作者基本信息】 西安建筑科技大学 ， 应用化学， 2010， 硕士

【摘要】 铋复合氧化物具有良好的铁电、压电、电光特性,在现代微电子、微机电系统、信息储存及光催化等方面有着广阔的应用前景。在这些性质之中,其作为可见光催化剂降解有机污染物和光解水制H2等引起了人们的广泛兴趣,同常用的TiO2相比,其禁带宽度小,可以利用太阳光中的可见光。本论文主要通过水热法合成了Bi12SiO20,Bi4Ti3O12,BiFeO3三种铋复合氧化物,通过对合成温度和时间做平行实验,分别得出合成这三种物质的最佳合成条件,并用XRD, SEM,热分析系统,拉曼光谱,VSM对产物进行表征,通过对甲基橙的脱色反应来测试其的光催化性能。以Na2SiO3和Bi(NO3)3·5H2O为原料,KOH为矿化剂,聚乙二醇6000为分散剂,水热合成了单相Bi12SiO20粉体,考察了反应条件对物相结构、结晶状况、晶粒尺寸以及晶体形貌的影响。结果表明,在180℃反应9h就可以制备出不规则形状的Bi12SiO20晶粒,室温下Bi12SiO20降解甲基橙为1.35级反应,在高压汞灯的照射下,4h对甲基橙的降解率为55%左右,反应的速率常数为5.932(mol-dm-3)-0.35·min-1。以TiO2和Bi(NO3)3·5H2O为原料,KOH为矿化剂,聚乙二醇6000为分散剂,水热合成了单相Bi4Ti3O12粉体,考察了反应条件对物相结构、结晶状况、晶粒尺寸以及晶体形貌的影响。结果表明,在200℃反应9h就可以制备出针状的Bi4Ti3O12粉体,室温下Bi4Ti3O12降解甲基橙为0.64级反应,在高压汞灯的照射下,4h对甲基橙的降解率可达95%左右,反应的速率常数为6.596(mol·dm-3)0.36·min-1。以Fe(NO3)3·9H2O和Bi(NO3)3·5H2O为原料,KOH为矿化剂,聚乙二醇6000为分散剂,水热合成了单相BiFeO3粉体,考察了反应条件对物相结构、结晶状况、晶粒尺寸以及晶体形貌的影响。结果表明,在200℃反应6h就可以制备出分散性好,颗粒发育良好及分布均匀的BiFeO3粉体。室温下BiFeO3降解甲基橙为0.81级反应,在高压汞灯的照射下,4h对甲基橙的降解率可达90%,反应的速率常数为7.375(mol·dm-3)0.19·min-1。更多还原

【Abstract】 Bismuth complex oxides have wide application prospects in modern microelectronics, micro-electromechanical systems, information storage, photocatalytic activity, and so on, due to the ferroelectric, piezoelectric and electro-optical properties. Among all these properties, the photodegradation of organic pollution and photocatalytic H2 evolution reaction under visible lights are attractive.When compared with the most widly used photocatalysts, TiO2, they have smaller energy gaps which can use the visible lights of the solar energy.In this paper, Bi12SiO20, Bi4Ti3O12, BiFeO3,three kinds of bismuth complex oxides, were synthesized by hydrothermal methods.The optimized reaction temperature and time were given by different parallel experiments. The sample were characterized by XRD,SEM, thermal analysis, Raman spectra and VSM. The photocatalytic properties were investigated by degradation of methyl orange.Single phase of Bi12SiO20 powder has been synthesized by the hydrothermal method, using bismuth nitrate (Bi(NO3)3·5H2O) and sodium metasilicate (Na2Si03) as raw materials, potassium hydroxide (KOH) as mineralizer, polyethylene glycol (HO(CH2CH2O)nH) 6000 as dispersant. The effects of reaction conditions on the product were investigated. The experiment results show that well particles of Bi12SiO20 powder can be obtained at 180℃for 9h which has high photocatalytic properties.The degradation rate of methyl orange is about 55% under high pressure mercury lamp irradiation for 4h. The reaction is 1.35 order reaction, and the rate constant is 5.932(mol·dm-3)-0.35·min-1 under ambient temperature.Single phase of Bi4Ti3O12 powder has been synthesized by the hydrothermal method, using bismuth nitrate (Bi(NO3)3-5H2O) and titamium dioxide (TiO2) as raw materials, potassium hydroxide (KOH) as mineralizer, polyethylene glycol (HO(CH2CH2O)nH) 6000 as dispersant. The effects of reaction conditions on the product were investigated. The experiment results show that well particles of Bi4Ti3O12 needle can be obtained at 200℃for 9h which has high photocatalytic properties. The degradation rate of methyl orange is nearly about 95% under high pressure mercury lamp irradiation for 4h. The reaction is 0.64 order reaction, and the rate constant is 6.596(mol·dm-3)0.36·min-1 under ambient temperature.Single phase of BiFeO3 powder has been synthesized by the hydrothermal method, using bismuth nitrate (Bi(NO3)3·5H2O) and iron nitrate (Fe(NO3)3-9H2O) as raw materials, potassium hydroxide (KOH) as mineralizer, polyethylene glycol (HO(CH2CH2O)nH) 6000 as dispersant. The effects of reaction conditions on the product were investigated. The experiment results show that well particles of BiFeO3 powder can be obtained at 200℃for 6h which has high photocatalytic properties. The degradation rate of methyl orange is nealy 90% under high pressure mercury lamp irradiation for 4h. The reaction is 0.81 order reaction, and the rate constant is 7.375(mol-dm-3)0.19·min-1 under ambient temperature.更多还原