Department of Materials Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 8410501, Israel.
Adv Mater. 2018 Oct;30(41):e1706300. doi: 10.1002/adma.201706300. Epub 2018 May 31.
Oxides are widely used for energy applications, as solid electrolytes in various solid oxide fuel cell devices or as catalysts (often associated with noble metal particles) for numerous reactions involving oxidation or reduction. Defects are the major factors governing the efficiency of a given oxide for the above applications. In this paper, the common defects in oxide systems and external factors influencing the defect concentration and distribution are presented, with special emphasis on ceria (CeO ) based materials. It is shown that the behavior of a variety of oxide systems with respect to properties relevant for energy applications (conductivity and catalytic activity) can be rationalized by general considerations about the type and concentration of defects in the specific system. A new method based on transmission electron microscopy (TEM), recently reported by the authors for mapping space charge defects and measuring space charge potentials, is shown to be of potential importance for understanding conductivity mechanisms in oxides. The influence of defects on gas-surface reactions is exemplified on the interaction of CO and H O with ceria, by correlating between the defect distribution in the material and its adsorption capacity or splitting efficiency.
氧化物被广泛应用于能源领域，可用作各种固体氧化物燃料电池器件中的固体电解质，也可用作涉及氧化或还原的众多反应的催化剂（通常与贵金属颗粒相关联）。缺陷是影响给定氧化物在上述应用中效率的主要因素。本文介绍了氧化物体系中的常见缺陷以及影响缺陷浓度和分布的外部因素，特别强调了基于氧化铈（CeO ）的材料。结果表明，通过对特定体系中缺陷的类型和浓度进行一般性考虑，可以合理推断出各种氧化物体系在与能源应用相关的性能（电导率和催化活性）方面的行为。作者最近报道的一种基于透射电子显微镜（TEM）的新方法，用于空间电荷缺陷的映射和空间电荷势的测量，对于理解氧化物中的电导率机制具有潜在的重要意义。通过关联材料中的缺陷分布与其吸附能力或分解效率，说明了缺陷对气-固表面反应的影响，以氧化铈与 CO 和 H O 的相互作用为例。
