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利用溶胶-凝胶法制备了不同掺杂量及不同温度焙烧的Tm掺杂TiO2纳米粉体。采用X射线衍射(XRD),紫外-可见漫反射谱(DRS)和光致发光光谱(PL)技术研究了Tm掺杂量和焙烧温度对其相结构、晶粒尺寸、光吸收及光致发光性能的影响;并以亚甲基蓝(MB)溶液的光催化降解评价其光活性。结果表明:低量Tm掺杂强烈抑制TiO2由锐钛矿相向金红石相转变,减小晶粒尺寸;然而,Tm掺杂量增加,抑制相变作用减弱。Tm掺杂导致样品的紫外吸收能力略有降低,光吸收带边蓝移。Tm掺杂导致样品的PL谱强度降低(0.05%<0.075%<0.025%≈0.1%<0%),光活性升高(0.075%>0.05%>0.1%>0.025%>0%),但二者顺序并不完全一致。低量Tm掺杂能有效提高纳米TiO2的光活性;当Tm掺杂量为0.075%(质量分数)、焙烧温度为550℃时,制得样品呈双相结构,锐钛矿相占91%,晶粒尺寸为24.48 nm,其光活性最佳。光活性提高的主要根源是Tm掺杂能有效促进纳米TiO2表面光生e-/h+分离,提高量子化效率。
Tm doped TiO2 nano-powders with different doping amount and different temperature were prepared by sol-gel method. The phase structure, grain size, light absorption and photoluminescence (PL) of Tm were studied by X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) The photocatalytic degradation of methylene blue (MB) solution was used to evaluate its photoactivity. The results show that low Tm doping strongly inhibits the transformation of TiO2 from rutile to rutile and decreases the grain size. However, the amount of Tm doping increases and the phase transition inhibition decreases. Tm doping led to a slight decrease in the UV absorbance of the sample, blue absorption of the band edge. The Tm doping results in the decrease of the PL spectrum intensity (0.05% <0.075% <0.025% ≈0.1% <0%) and the photoactivity (0.075%> 0.05%> 0.1%> 0.025%> 0% The order is not exactly the same. Low Tm doping can effectively improve the photocatalytic activity of TiO2. When the Tm content is 0.075% (mass fraction) and the calcination temperature is 550 ℃, the sample has a dual phase structure with anatase phase accounting for 91% The grain size is 24.48 nm and its photoactivity is the best. The main reason for the increase in photoactivity is that Tm doping can effectively promote photo-e- / h + separation on the surface of the nano-TiO2 and improve the quantum efficiency.