Abstract

Using europium trioxide(Eu₂O₃), ammonium metavanadate(NH₄VO₃), nitric acid, ammonium hydroxide and citric acid hexahydrate, the EuVO₄ was prepared by hydrothermal method. The structure and morphology of samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and UV-visible diffuse reflectance spectroscopy (DRS). Using methyl orange as simulated sewage, the visible-light photocatalytic activities of EuVO₄ were investigated on synthesis temperatures and illumination time. The results showed that the purely rare earth perovskite structure EuVO₄ was prepared in the range of hydrothermal temperature of 120 ∼ 180 °C. The EuVO₄ particles are uniform size prepared in 140 °C, which have a particle size of 2 ∼ 4 μm and an optical band gap of 2.07 eV. The photocatalytic experiment demonstrates that hydrothermal synthesis at 140 °C is the best. Under visible-light irradiation, the degradation rate methyl orange of 10 mg/L can reach 93% for 60 min. The EuVO₄ shows excellent photocatalytic activities.

摘要

以三氧化铕(Eu ₂ O ₃ )、偏钒酸铵(NH ₄ VO ₃ )、硝酸、氢氧化铵和六水柠檬酸为原料，采用水热法制备EuVO ₄。采用热重和差示扫描量热法(TG-DSC)、粉末X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)和紫外-可见漫反射对样品的结构和形貌进行表征反射光谱（DRS）。_{以甲基橙为模拟污水，EuVO 4}的可见光光催化活性研究了合成温度和光照时间。结果表明，纯稀土钙钛矿结构的EuVO ₄是在120～180℃的水热温度范围内制备的。EuVO ₄颗粒在140 ℃下制备，粒径均一，粒径为2～4 μm，光学带隙为2.07 eV。光催化实验表明，140℃的水热合成效果最好。在可见光照射下，10 mg/L的甲基橙在60 min内降解率可达93%。EuVO ₄显示出优异的光催化活性。