低量Tm掺杂TiO_2纳米粉体的光致发光特性及光活性  

Photoluminescent Properties and Photoactivities of Low Amount Tm-doped TiO_2 Nano-Powders

作　　者：卢智宇[1] 姜洪泉[1] 李井申[1] 王城英[1] 闫盼盼[1] 

机构地区：[1]哈尔滨师范大学化学化工学院,黑龙江哈尔滨150025

出　　处：《中国稀土学报》2010年第5期553-559,共7页Journal of the Chinese Society of Rare Earths

基　　金：黑龙江省教育厅科学技术研究项目(11551115);哈师大青年学术骨干资助计划项目(08XBSK89)资助

摘　　要：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。The Tm-doped TiO2 nano-powders with different Tm-doping contents and calcined at different temperatures were prepared by the sol-gel method.The effects of Tm-doping contents and calcination temperatures on their phase structures,crystallite sizes,light absorption performances and photoluminescent properties were investigated by the XRD,DRS and PL.Their photoactivities were evaluated by the photocatalytic degradation of methylene blue（MB） in aqueous solution.The results indicated that the presence of low amount Tm in TiO2 could strongly inhibit the phase transformation from anatase to rutile,and restrain the crystal grain growth.However,the effect of inhibition could gradually weaken with the increase of Tm-doping content.The Tm-doping could result in both a slight decrease of their light absorption performance in ultraviolet region and a blue shift of their optical absorption edge.The intensity sequence of PL spectrum for the Tm-doping samples was 0.05%〈0.075%〈0.025%≈0.1%0%,while their photoactivity sequence was 0.075%〉0.05%〉0.1%〉0.025%〉0%.Consequently,it could be verified that the decrease sequence of the PL spectrum intensities did not accord with the increase sequence of their photoactivities completely.A low amount Tm-doping could effectively enhance the photoactivity of TiO2 nano-powders.The Tm-doped sample with Tm-doping contents of 0.075% calcined at 550 ℃ showed the highest photoactivity,which presented two phases structure and included the anatase phase of 91%.Its crystallite size was 24.48 nm.The main origin of the higher photoactivity for the Tm-doped TiO2 was that the separation of the photogenerated electron-hole pairs could be promoted by Tm-doping,leading to increasing quantum efficiency.

关 键 词：纳米TIO2 Tm掺杂 光致发光 光活性 

分 类 号：O643[理学—物理化学]