铕掺杂TiO_2的制备及其可见光光催化性能研究

Preparation and Photocatalytic Properties of Eu-Doped TiO_2 under Visible Light Irradiation

采用溶胶-凝胶法制备了不同铕(Eu)掺杂量的TiO2纳米颗粒(Eu-TiO2),利用透射电镜(TEM),X射线光电子能谱(XPS),X射线衍射(XRD)及紫外可见漫反射(UV-Vis DRS)等方法对Eu-TiO2进行了物理特性的初步表征.结果表明:与未掺杂纳米TiO2比较,Eu-TiO2禁带宽度变窄,具有可见光光催化活性.在可见光下(λ≥420nm)照射下,以光催化降解染料罗丹明B(Rho-damine B,RhB)为目标反应,探讨了Eu-TiO2不同制备条件对RhB降解光催化活性的影响,优化得到制备高活性Eu-TiO2最佳pH为3、掺杂比例(nEu/nTi)为0.05%、煅烧温度为500℃.研究了可见光照射下Eu-TiO2降解RhB和无色有机小分子水杨酸(SA)光催化反应条件及降解特性,RhB的12h深度氧化矿化率为60.2%,SA的8h降解率达到100%.通过跟踪测定可见光下Eu-TiO2光催化反应过程中氧化物种的变化,研究了可见光激发Eu-TiO2光催化反应机理,表明其光催化反应主要涉及羟基自由基(.OH)历程.

Eu-doped TiO2 nano-particles had been prepared by sol-gel method and characterized by transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD） and UV-visible diffuse reflectance spectra （UV-Vis DRS）. The results showed that the band gap of Eu-TiO2 was narrower than that of TiOz. Eu-TiO2 had photocatalytic activity. The effect of preparation conditions of orgaric compounds on the degradation of rhodamine B（RhB） was studied. The optimal conditions were pH 3, nEu/nTi= 0.05% and calcination temperature 500 ℃. The degradation of rhodamine B （RhB） and salicylic acid （SA） under visible light irradiation were used as testing reactions to analyze the activity of Eu-TiO2 with different loadings. The results showed that RhB and SA were effectively degraded and mineralized, and the degradation reaction was predominated by the hydroxyl radical （.OH）.