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采用柠檬酸溶胶-凝胶法(Sol-Gel),以 Ce(NO3)3·6 H 2 O、Gd2 O3、柠檬酸为原料,制备纳米级 Cex-Gd1-x O2-δ复合氧化物,对制得的样品进行 X 射线衍射、比表面、扫描电镜及能谱和透射电镜表征,研究样品的组成、晶粒大小、比表面积和样品形貌特征。结果表明,Cex Gd1-x O2-δ复合氧化物在600℃和800℃焙烧后均形成均匀的面心立方 CeO2基固溶体和/或体心立方 Gd2 O3基固溶体。单组分 Gd2 O3样品在800℃焙烧后形成具有体心立方的Gd2 O3物相,经600℃焙烧后还同时含有43%(质量分数)的六方 Gd2 O2 CO3晶型。对于同一 Gd3+掺杂比例样品,焙烧温度越高,晶粒越大,比表面积越小；同一焙烧温度样品的晶粒尺寸随 Gd3+掺杂量增大先减小后增大,但均小于单组分 CeO2和 Gd2 O3,且 Ce0.5 Gd0.5 O2-δ样品晶粒最小。表明复合氧化物的形成提高了抗烧结能力,形成更多孔隙结构,使样品晶粒变小,比表面积变大,并且 x=0.5为形成最小纳米级样品的最佳比例。

A series of nano-sized Cex Gd1 -x O2-δ powders were synthesized by the sol-gel method.The Ce-(NO3 )3 ·6 H 2 O and Gd2 O3 were used as raw material and citric acid as fuel.X-ray diffraction,BET,SEM-EDS and TEM were used to observe the characteristics of the samples such as grain size,specific surface area and the compact-ness.The results showed that Cex Gd1 -x O2-δ(x≥0.4)composite oxides formed the CeO2-based solid solution and/or Gd2 O3-based solid solution after calcined at 600 ℃ and 800 ℃.Gd2 O3 existed as body-centered cubic after calcination at 800 ℃,and it also contained the structure of hexagonal Gd2 O2 CO3 after calcined at 600 ℃.For the same Gd3 + do-ping ratio sample,the higher calcination temperature,the larger grain size,and the smaller surface area.At the same calcination temperature,with the increasing of the doping amount of Gd3 + ,the grain size of the samples first de-creased and then increased.The grain sizes of these doped oxides were smaller than single CeO2 and Gd2 O3 .Ce0.5-Gd0.5 O2-δ had the smallest grain size.Experiments indicated that the formation of the Cex Gd1 -x O2-δ solid solutions can enhance the thermal stability,and consequently create more void structure which leads to smaller grain size and larger surface area.The minimum grain size can be obtained by an x value of 0.5.