摘要
以钛酸四丁酯,La2O3和Ce(NO3)3·6H2O为原料,采用溶胶-凝胶法制备了纯的和分别掺杂5mol%镧和铈的TiO2纳米粒子,并利用XRD,TG-DTA,TEM和XPS等测试技术对样品的晶型、尺寸和形貌等进行了表征,主要考察了镧和铈的掺杂对TiO2的晶粒尺寸和锐钛矿→金红石结构相变的影响,并初步的探讨了镧和铈的作用机理.结果表明,600℃焙烧而获得的TiO2纳米粒子具有与P-25型TiO2粒子相类似的组成、结构、形貌和粒子尺寸;掺杂剂镧和铈分别以La2O3和CeO2小团簇形式存在,并比较均匀的弥散在TiO2纳米粒子中,二者的掺杂抑制了锐钛矿晶粒的增长和锐钛矿→金红石的结构相变,使相变温度显著提高,晶格畸变增大,而镧比铈的作用更加显著.镧和铈的作用机理可能主要与掺杂离子的半径和价态以及稀土氧化物的存在和熔点等有关.
The pure and respectively doped 5mol% La and Ce TiO_2 nanoparticles were prepared by the sol-gel method using the Ti(OC_4H_9)_4, La_2O_3and Ce(NO_3)_3·6H_2O as the raw materials, and their properties like crystallographic forms, particle size, and morphology et al. were characterized by the testing techniques such as XRD, TG-DTA, TEM and XPS. The effects of doping La and Ce on the crystallite size and phase transformation from anatase to rutile of TiO_2 were investigated, and the acting mechanisms of the dopants La and Ce were also discussed. The results showed that the pure TiO_2 nanoparticles calcined at 600℃ had similar composition, structure, morphology and particle size with international P-25 TiO_2 samples; The dopants La and Ce were well-proportioned dispersed respectively in the TiO_2 nanoparticles as the chemical forms of La_2O_3and CeO_2 with fine size, and all of them greatly inhibited the increase of crystallite size and phase transformation from anatase to rutile, also made the phase transformation temperature and crystal lattice disorder increase, but the effects of La were greater than those of Ce. The acting mechanisms possibly had close relations with the radius and valence state of doped rare earth ions as well as the existence and melting point of rare earth oxides.
出处
《材料科学与工艺》
EI
CAS
CSCD
2004年第2期148-152,共5页
Materials Science and Technology
基金
国家自然科学基金资助项目(20171016
20301006)
教育部重点项目计划资助项目
黑龙江省自然科学基金资助项目 (B0 3 0 5)
黑龙江省杰出青年科学基金资助项目 (2 0 0 2 )
黑龙江大学博士科研启动基金
黑龙江大学杰出青年基金资助项目 (2 0 0 3 ).
