Hydrothermal Synthesis, Characterization And Application Of Bismuth Complex Oxides

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.