The atomic scale reshuffling during oxygen ion conductivity in co-doped ceria lattice at intermediate temperature (400–700 °C) range are investigated by in-situ measurement using spectroscopic tools EXAFS, XANES, Raman and XRD. Oxy-ion hopping site decide migration barrier through ceria lattice and thus activation energy for conductivity; present interest is to extrapolate ionic conductivity by exploring oxy-ion hopping site. Hydrothermally synthesized nanocrystalline Sm-based aliovalent and isovalent co-doped ceria systems with optimized dopant content are used for the study. Charge-size effect of aliovalent and isovalent co-dopant pair on ceria lattice are revealed from Rietveld refinement of XRD data. HR-TEM images confirmed nanoscale dimensions (~15 nm) of grains of as-calcined as well as sintered samples (100–150 nm) with well defined grain boundaries. HT-EXAFS data are extracted to get information of co-ordination number (CN), interatomic spacing (IS) and atomic disorder at 1st shell (NN) and 2nd shell (NNN) site. The rate of change of CN and IS with temperature are closely associated with the rate of oxygen vacancies (i) formation, (ii) relaxation and (iii) dissociation at NN and NNN site of cations; which lead to atomic scale reshuffling at NN and NNN site of cations. Our work demonstrates, in aliovalent doped ceria, NN-site favour oxygen vacancies dissociation; while for isovalent dopant pair, NNN-site is proactive for oxygen vacancies dissociation. HT-Raman spectra also supported these results by disappearance of respective defect associated Raman mode. HT-XANES spectra revealed intrinsic oxygen vacancies dominancy in aliovalent co-dopant. The oxygen ion migration route through NN-site is found lower energetic than that of NNN-site as-confirmed from ionic conductivity data. The ionic conductivities of SmCa and SmSr aliovalent codoped ceria systems are obtained one order more than SmGd, SmDy and SmNd isovalent co-doped ceria systems. As well as activation energy of aliovalent co-doped ceria is lower than isovalent once.

通过使用光谱工具EXAFS，XANES，Raman和XRD进行原位测量，研究了在中等温度（400-700°C）范围内共掺杂二氧化铈晶格中氧离子传导性过程中的原子尺度转换。氧离子跳跃位点决定了通过二氧化铈晶格的迁移障碍，从而决定了活化能的传导性。目前的兴趣是通过探索氧离子跳跃位点来推断离子电导率。具有最佳掺杂剂含量的水热合成纳米晶Sm基铝价和等价共掺杂二氧化铈体系用于研究。从XRD数据的Rietveld改进中可以看出，二价共价掺杂物对二氧化铈晶格的电荷大小效应。HR-TEM图像证实了煅烧样品和烧结样品（100-150 nm）具有明确定义的晶界的纳米级尺寸（〜15 nm）。提取HT-EXAFS数据以获得第一壳（NN）和第二壳（NNN）部位的配位数（CN），原子间间距（IS）和原子无序的信息。CN和IS随温度的变化速率与氧空位的速率密切相关（i）形成，（ii）弛豫和（iii）在NN和NNN阳离子位点解离; 这会导致在NN和NNN阳离子位点发生原子级改组。我们的工作表明，在掺杂异价金属的二氧化铈中，NN位置有利于氧空位解离。而对于等价的掺杂剂对，NNN位点对于氧空位解离是积极的。HT-拉曼光谱也通过与拉曼模式相关的各个缺陷的消失而支持了这些结果。HT-XANES光谱显示在异价共掺杂物中固有的氧空位占优势。通过离子电导率数据确定，发现通过NN位置的氧离子迁移路径的能量低于NNN位置。Sm的离子电导率与Sm Gd，Sm Dy和Sm Nd等价共掺杂二氧化铈系统相比，获得的Ca和Sm Sr铝价共掺杂二氧化铈体系高一个数量级。铝价共掺杂二氧化铈的活化能也一次低于等价。