Ba_4In_2O_7的自蔓延燃烧合成及其光催化性能

Self-propagating Combustion Synthesis of Ba_4In_2O_7 and Its Photocatalytic Activity

以Ba(NO3)2和In(NO3)3为起始物,以甘氨酸为燃料,用自蔓延燃烧合成法制备四方晶系Ba4In2O7,用X射线衍射(XRD)、热重-差热分析(TG-DTA)、紫外-可见漫反射光谱(UV-vis DRS)和氮气吸附-脱附等温线(BET)等手段对样品进行表征,研究了合成条件对产物的形成和性能的影响。以罗丹明B(Rh B)为降解模型,研究了焙烧温度(T)、焙烧时间(t)、钡铟摩尔比(Ba/In)、甘氨酸与金属离子摩尔比(G/M)和Rh B初始浓度对样品光催化性能的影响。结果表明,在T=800℃、t=1 h、Ba/In=2∶1和G/M=2∶1条件下合成的Ba4In2O7具有四方晶系结构,纯度高,光催化活性优异。用高压汞灯(125 W)辐照3 h可将5 mg/L的Rh B溶液有效降解,其脱色率达到96.5%,降解过程服从一级动力学模型。

The compounds of tetragonal Ba4In2O7 were synthesized by self- propagating combustion synthesis method from raw materials of Ba(NO3)2, In(NO3)3and Glycine. The effect of synthesis conditions on the formation and photocatalytic activity of the compounds was investigated. The synthesized Ba4In2O7 was characterized by X- ray diffraction(XRD), thermogravimetric analysis- differential thermal analysis(TG- DTA), UV- visible diffuse reflectance spectroscopy(UV- vis DRS) and N2adsorption- desorption isotherms(BET), respectively. With rhodamine B(Rh B) as a model degradation compound, the effect of calcinations temperature(T), calcinations time(t), Ba to In molar ratio(Ba/In), Glycine to metal ion molar ratio(G/M) and the initial concentration of Rh B on the photocatalytic activity of Ba4In2O7 was investigated.The results show that the synthetic Ba4In2O7, prepared by conditions of T=800℃, t=1 h, Ba/In= 2∶1 and G/M=2∶1, has tetragonal structure, higher purity and excellent photocatalytic activity. The Rh B(5 mg/L) can be completely decomposed in 3 h under lighting of a high pressure mercury lamp(125 W), and the decolorization rate of Rh B can reach 96.5%. The degrading process fits the first-order kinetic model.