Coduri Mauro, Masala Paolo, Allieta Mattia, Peral Inma, Brunelli Michela, Biffi Carlo Alberto, Scavini Marco
Dipartimento di Chimica, Università degli Studi di Milano , Via C. Golgi 19, I-20133 Milano, Italy.
ESRF-The European Synchrotron , 71, Avenue des Martyrs, 38043, Grenoble, France.
Inorg Chem. 2018 Jan 16;57(2):879-891. doi: 10.1021/acs.inorgchem.7b02896. Epub 2017 Dec 27.
The structure evolution in the CeO-SmO system is revisited by combining high resolution synchrotron powder diffraction with pair distribution function (PDF) to inquire about local, mesoscopic, and average structure. The CeO fluorite structure undergoes two phase transformations by Sm doping, first to a cubic (C-type) and then to a monoclinic (B-type) phase. Whereas the C to B-phase separation occurs completely and on a long-range scale, no miscibility gap is detected between fluorite and C-type phases. The transformation rather occurs by growth of C-type nanodomains embedded in the fluorite matrix, without any long-range phase separation. A side effect of this mechanism is the ordering of the oxygen vacancies, which is detrimental for the application of doped ceria as an electrolyte in fuel cells. The results are discussed in the framework of other Y and Gd dopants, and the relationship between nanostructuring and the above equilibria is also investigated.
通过结合高分辨率同步辐射粉末衍射和对分布函数（PDF）来重新研究CeO - SmO体系中的结构演变，以探究局部、介观和平均结构。CeO萤石结构通过Sm掺杂经历两次相变，首先转变为立方（C型）相，然后转变为单斜（B型）相。虽然C相向B相的分离是完全的且在长程尺度上发生，但在萤石相和C型相之间未检测到混溶间隙。相反，这种转变是通过嵌入萤石基体中的C型纳米域的生长发生的，没有任何长程相分离。这种机制的一个副作用是氧空位的有序化，这对掺杂氧化铈作为燃料电池中的电解质的应用是不利的。在其他Y和Gd掺杂剂的框架内讨论了结果，并且还研究了纳米结构与上述平衡之间的关系。
