TiO_2超微粒子的量子尺寸效应与光吸收特性  

THE QUANTUM SIZE EFFECT AND LIGHT ABSORPTION OF ULTRAFINE TITANIA PARTICLES

作　　者：余锡宾[1] 王桂华[1] 罗衍庆 李和兴[1] 

机构地区：[1]上海师范大学化学系,上海200234

出　　处：《催化学报》1999年第6期613-618,共6页

基　　金：上海市教委科技发展基金

摘　　要：利用Ｒａｍａｎ 激光光谱，ＸＲＤ， ＴＥＭ，ＳＥＭ 和ＵＶＶｉｓ 等手段研究了ＴｉＯ２ 超微粒子的量子尺寸效应与光吸收特性． 结果发现： 由Ｔｉ（ＯＢｕ）４ 在较低ｐＨ 值的水解条件下制得的ＴｉＯ２ 溶胶粒径为５ ～１０ ｎｍ ； 随着热处理温度的升高，ＴｉＯ２ 微粒的粒径增大，经４７３ ～６７３ Ｋ 热处理得到的ＴｉＯ２ 超微粒子粒径为１０ ～２０ ｎｍ ， 呈不规整的锐钛矿型结构．ＴｉＯ２ 的拉曼峰随热处理温度升高而发生红移，表现出量子尺寸效应． 热处理温度升高到８７３ Ｋ 时，粒径增大到３０ ｎｍ 左右，呈锐钛矿型与金红石型混晶结构． 温度进一步升高时，金红石相增多． 由于金红石型ＴｉＯ２ 微粒带隙减小，也使拉曼峰出现红移． 当ＴｉＯ２ 微粒的尺寸明显增大，超出量子尺寸效应范围（２０ ｎｍ）时，其拉曼峰不发生位移． 锐钛矿型ＴｉＯ２ 超微粒子在紫外光区有较好的光吸收性能，并有较高的光催化活性．在较高ｐＨ 值的水解条件下得到的多孔大颗粒ＴｉＯ２ ，对紫外光有散射作用，有效光吸收及光催化降解活性均降低．TiO 2 sol particles (5～10 nm) was prepared by hydrolysis of Ti(OBu) 4. The ultrafine particles were thermally treated at different temperatures from 473 K to 1?073 K. The results of XRD and Raman spectroscopy showed that the samples in the form of ultrafine particles ( ca 10～20 nm) obtained at lower pH hydrolytic condition with Ti(OBu) 4 as the precursor treated at temperature lower than 673 K were irregular anatase crystal, and the quantum size effect was observed. The TiO 2 particle size was increased with the increase of the treatment temperature. When the treatment temperature increased up to 873 K, the samples obtained become a mixture of anatase phase and rutile phase and the particle size was increased to ca 30 nm. The red shifting in Raman spectra for the TiO 2 samples with small crystalline size was found. That red shifting was also observed with the increase of the rutile phase in the mixed crystalline phase. UV Vis measurements showed that the anatase particles sized less than 20 nm exhibited excellent light absorption capacity and photocatalytic performance. The porous particles with big size are prepared in high pH hydrolytic condition. The porous particles have higher crystallization temperature than TiO 2 ultrafine particles, and have low effective light absorption capacity and photocatalytic performance owing to their UV light scattering.

关 键 词：二氧化钛 超微粒 量子尺寸效应 光吸收 光催化剂 

分 类 号：O643.36[理学—物理化学]