Ce1-xPrxO2-δ(x=0.05～0.30)固溶体的合成及其性质研究

Synthesis and Properties of the Solid Solution Ce_(1-x)Pr_xO_(2-δ) (x=0.05～0.30)

利用溶胶-凝胶法合成了固溶体Ce1-xPrxO2-δ(x=0.05～0.30).X射线衍射(XRD)分析表明,在x≤0.30的范围内形成了单相萤石结构固溶体Ce1-xPrxO2-δ;X射线光电子能谱(XPS)结果表明,样品中氧缺位浓度随掺杂量增大而增大,铈离子主要为Ce4+离子,镨离子以混合价态Pr3+和Pr4+存在;拉曼光谱(Raman)观察到两个峰,458cm-1峰为特征F2g振动谱带,较宽的570cm-1峰与样品中氧离子缺位有关;交流阻抗谱测试表明,固溶体Ce1-xPrxO2-δ的电导率随掺杂量增加而增大,x=0.2时,电导率达到最大,活化能较低,σ600℃=3.28×10-2S/cm,σ700℃=6.06×10-2S/cm,Ea=0.54eV(250～650℃),Ea=0.49eV(650～800℃).

Solid solutions Ce1-xPrxO2-δ（x=0.05-0.30） were synthesized by a sol-gel method. The X-ray diffraction analysis showed that solid solutions Ce1-xPrxO2-δ were crystallized in a single fluorite structure in the range of x≤0.30. XPS analysis suggested that the oxygen vacancy concentration increased with increasing the dopant content x, and the mixed valence Pr^3＋/Pr^4＋ ions and major Ce^4＋ ions existed in the solid solutions. The Raman spectra exhibited two peaks. The 458 cm^-1 peak was attributed to Raman active F2g mode that was assigned to a symmetric breathing mode of oxygen atoms around cerium ions. The broad 570 cm^-1 peak was attributed to oxygen vacancies. Impedance spectra showed conductivity values of Ce1-xPrxO2-δ （x=0.05-0.30） which were increased with the dopant content x and reached the maximum at x=0.20, and the relatively low activation energy data, σ600 ℃=3.28× 10^-2 S·cm^-1, σ700℃ =6.06× 10^-2 S·cm^-1, Ea=0.54 eV （250-650 ℃）, and Ea=0.49 eV （650-800 ℃）.