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 Pr3＋/Pr4＋ ions and major Ce4＋ 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 ℃).

Key words: sol-gel method, Ce1－xPrxO2－δ, X-ray photoelectron spectroscopy, Raman spectrum, conductivity