Wet chemical synthesis and physical characterization of doped CeO2 nanoparticles

Solid electrolytes based on doped cerium oxide, Ce(M)O2-δ (M = rare-earth cations), are of considerable interest for potential use in low temperature solid oxide fuel cells (LTSOFCs) due to its higher ionic conductivity than YSZ based solid electrolyte.  In this research work, crystalline, pure Ce1-xMxO2-δ (where M = Gd or Sm, x = 0.10 or 0.20) based nanoparticles were prepared by chemical precipitation method in presence of surfactant (polyvinyl pyrollidone). The intermediate compound (mixture of hydroxides) was subjected to TGA/DTA in order to find out the temperature at which the pure phase product is formed.  Then, the as prepared materials were heat treated systematically at 300, 450 and 600o C for 2 h each to get phase pure materials. The resultant nanoparticles were subjected to physical characterization techniques such as, XRD, FTIR, particle size analysis and SEM.  XRD results confirmed that all the powders had single-phase fluorite structure. Characteristic vibration mode of CeO2 was proved by FTIR. The presence of nanoparticles (50 – 100 nm) in the prepared materials was found out by particle size measurements and SEM. The results of physical characterization of the above materials are found to be good for application as alternate electrolytes in SOFC. However, these materials can be considered as suitable alternate electrolytes in LTSOFC systems only after studying their electrical characteristics.