An experimental investigation of the crystallographic,Raman and transport properties of the Ce_(1-x)(Nd_(0.74)Tm_(0.26))_xO_(2-x/2)(0.1≤x≤0.6) doped ceria system was performed with the aim of setting out correlation...An experimental investigation of the crystallographic,Raman and transport properties of the Ce_(1-x)(Nd_(0.74)Tm_(0.26))_xO_(2-x/2)(0.1≤x≤0.6) doped ceria system was performed with the aim of setting out correlations between structural features and ionic conductivity of the material.The chosen composition ensures that the average size of the Nd^(3+) and Tm^(3+) doping ions coincides with the one of Sm^(3+);even so,the studied system presents larger cell parameters and a wider compositional extent of the CeO_(2)-based solid solution than Sm-doped ceria.Moreover,the occurrence of two different activation energies to ionic conduction below and above ~750 K determines the existence of two distinct conduction regimes.The described experimental results agree with the formation below the threshold temperature of1 V_O2 Tm'_(Ce) trimers,which promote the incorporation of Nd'_(Ce) isolated defects into the CeO_(2)-based solid solution.In the high temperature range the dissociation of trimers induces the appearance of a lower activation energy;the extrapolation of its value at infinite dilution provides a result in good accordance with the expected binding energy of 1 V_ORE'_(Ce) dimers,pointing at their stability even in the high temperature conduction regime.展开更多
基金financially supported by Compagnia di San Paolo, in the frame of the project COLEUS – ID ROL: 32604。
文摘An experimental investigation of the crystallographic,Raman and transport properties of the Ce_(1-x)(Nd_(0.74)Tm_(0.26))_xO_(2-x/2)(0.1≤x≤0.6) doped ceria system was performed with the aim of setting out correlations between structural features and ionic conductivity of the material.The chosen composition ensures that the average size of the Nd^(3+) and Tm^(3+) doping ions coincides with the one of Sm^(3+);even so,the studied system presents larger cell parameters and a wider compositional extent of the CeO_(2)-based solid solution than Sm-doped ceria.Moreover,the occurrence of two different activation energies to ionic conduction below and above ~750 K determines the existence of two distinct conduction regimes.The described experimental results agree with the formation below the threshold temperature of1 V_O2 Tm'_(Ce) trimers,which promote the incorporation of Nd'_(Ce) isolated defects into the CeO_(2)-based solid solution.In the high temperature range the dissociation of trimers induces the appearance of a lower activation energy;the extrapolation of its value at infinite dilution provides a result in good accordance with the expected binding energy of 1 V_ORE'_(Ce) dimers,pointing at their stability even in the high temperature conduction regime.
