La3+掺杂TiO2纳米粉体的相组成和光催化性能  

Phase Composition and Photocatalytic Properties of La3+-doped TiO2 Nanopowders

作　　者：严继康[1] 荣雪荃 顾鑫 杜景红[1] 甘国友[1] Yan Jikang;Rong Xuequan;Gu Xin;Du Jinghong;Gan Guoyou(Kunming University of Science and Technology,Kunming 650093,China;University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]昆明理工大学,云南昆明650093 [2]北京科技大学,北京100083

出　　处：《稀有金属材料与工程》2020年第2期465-475,共11页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51362017);Major Science and Technology Special Plan of Yunnan Province(2018ZE004,2018ZE005)。

摘　　要：采用溶胶-凝胶法制备了La3+掺杂TiO2。利用XRD、TEM、HRTEM、STEM-EDS、XPS和UV-Vis对样品进行表征,讨论La3+掺杂TiO2在相变过程中的物相组成、平均晶粒尺寸、微观结构、化学态和紫外-可见吸收光谱等方面的变化。结果表明,掺杂La3+明显地抑制了TiO2的相转变和晶粒长大,有效地改善了TiO2的分散性,并减小了TiO2的平均颗粒尺寸。随着煅烧温度升高,La3+掺杂TiO2逐渐析出第二相La4Ti19O24,其会与TiO2板钛矿相形成非共格界面,并以不规则球体的形式在TiO2基体表面析出。第二相La4Ti19O24来源于点缺陷在La掺杂TiO2晶界的偏析,偏析驱动力主要是是弹性应变能。随着煅烧温度的升高,La3+掺杂TiO2中O 1s的原子分数逐渐降低,La 3d的原子分数逐渐升高,且La 3d主峰的高结合能端有一个能量损失峰,煅烧后存在Ti3+;掺杂La3+使TiO2的光吸收带边红移,但随着煅烧温度的升高,其光吸收带边蓝移。A sol-gel method was used to prepare La3+-doped TiO2 nanopowders.The sample was characterized with XRD,TEM,HRTEM,STEM-EDS,XPS and ultraviolet-visible(UV-Vis) spectroscopy.The changes of the La3+-doped TiO2 in the phase transition were discussed on the aspects of its phase composition,the average grain size,the microstructure,the chemical states and UV-Vis absorption spectroscopy.The results show that doping with La3+ significantly suppresses the phase change and grain growth of TiO2.It effectively improves the TiO2 dispersibility and reduces the average particle size of TiO2.With the increase of the calcination temperature,the second phase La4Ti19O24 gradually precipitates from the La3+-doped TiO2 and forms an incoherent interface with the brookite TiO2 phase,which precipitates in the form of irregular spheres on the surface of the TiO2 base.Secondary phases are originated from segregation of point defects LaTi at grain boundaries in La3+ doped TiO2.The segregation driving force is mainly the elastic strain energy.With the increase of calcining temperature,the atomic fraction of the O1S in the La3+-doped TiO2 gradually decreases,and that of the La3d gradually increases.There is an energy loss peak at the higher binding-energy side of the main peak of the La3 d,and Ti3+ exists after the calcination.La3+doping makes the optical absorption band edge of the TiO2 red-shift.But with increasing the calcination temperature,the optical absorption bandedge blue shifts.

关 键 词：二氧化钛 相变 镧 光催化 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学] TB383.1[一般工业技术—材料科学与工程]