In this study, the fabrication and characterization of pure and gadolinium (Gd) doped ceria nanostructures (Ce1-xGdxO2-delta where x=0.05, 0.1 and 0.2) are investigated. The origin of defect formation has been systematically investigated by XRD and UV-Visible Raman. All the fabricated ceria are found to be "Nanosponge" morphology which is observed by using FESEM technique. The charge transfer of O2- ions and Ce3+/Ce4+ in the ceria host due to these defect structures are studied by UV-DRS. Impedance analysis is showed an enhanced ionic conductivity for 5% Gd doped ceria compared to other concentration of Gd, revealing that the dopant concentration is a critical parameter in engineering a large number of vacancy defects in ceria nanostructures. (C) 2012 Elsevier Ltd. All rights reserved.