Anomalous and nonanomalous surface X-ray diffraction is used to investigate the atomic structure and composition of the yttria-stabilized zirconia (YSZ)(111) surface. By simulation it is shown that the method is sensitive to Y surface segregation, but that the data must contain high enough Fourier components in order to distinguish between different models describing Y/Zr disorder. Data were collected at room temperature after two different annealing procedures. First by applying oxidative conditions at 10− 5 mbar O2 and 700 K to the as-received samples, where we find that about 30% of the surface is covered by oxide islands, which are depleted in Y as compared with the bulk. After annealing in ultrahigh vacuum at 1270 K the island morphology of the surface remains unchanged but the islands and the first near surface layer get significantly enriched in Y. Furthermore, the observation of Zr and oxygen vacancies implies the formation of a porous surface region. Our findings have important implications for the use of YSZ as solid oxide fuel cell electrode material where yttrium atoms and zirconium vacancies can act as reactive centers, as well as for the use of YSZ as substrate material for thin film and nanoparticle growth where defects control the nucleation process.

中文翻译：

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氧化钇稳定的氧化锆 (111) 表面的原子结构和组成

异常和非异常表面 X 射线衍射用于研究氧化钇稳定氧化锆 (YSZ)(111) 表面的原子结构和组成。仿真表明该方法对 Y 表面偏析敏感，但数据必须包含足够高的傅立叶分量，以便区分描述 Y/Zr 无序的不同模型。经过两次不同的退火程序后，在室温下收集数据。首先，通过在 10-5 mbar O2 和 700 K 下对原样应用氧化条件，我们发现大约 30% 的表面被氧化物岛覆盖，与本体相比，它们在 Y 中耗尽。在 1270 K 的超高真空中退火后，表面的岛形形态保持不变，但岛和第一近表面层明显富含 Y。此外，Zr 和氧空位的观察表明多孔表面区域的形成。我们的研究结果对 YSZ 作为固体氧化物燃料电池电极材料的使用具有重要意义，其中钇原子和锆空位可以作为反应中心，以及 YSZ 作为薄膜和纳米颗粒生长的基底材料，其中缺陷控制成核过程。