Hydrothermal synthesis and properties of Ce1-xEuxO2-δ solid solutions

The structure, thermal expansion coefficients and ionic and electronic conductivities of Ce1-xEuxO2-delta (x = 0-0.50) solid solutions, prepared hydrothermally for the first time, were investigated. The uniformly small particle size (40-55 nm) of the hydrothermally prepared materials allows sintering of the samples into highly dense ceramic pellets at 1300-1400 degrees C, a significantly lower temperature than 1600-1650 degrees C, which is required for samples prepared by solid-state techniques. X-ray absorption spectroscopy (XAS) was used to establish the pure Eu3+ character of the europium ions; XAS also reflects local disorder effects. The highest conductivity was found for Ce0.85Eu0.15O1.925-delta (sigma(700 degrees C) = 2.6 X 10(-2) S/cm, E-a = 0.66 eV) with predominantly oxide-ion mobility. (C) 2000 Elsevier Science S.A. All rights reserved.