UV and Visible Raman Studies of Oxygen Vacancies in Rare-Earth-Doped Ceria

作者：Ming Hui Guo, Ji-Qing Lu, Yanni Wu, Yuejuan Wang, Meng‐Fei Luo · 发表于：Langmuir · 年份：2011 · DOI：10.1021/la200292f · 被引用次数：517 · 研究领域：Catalytic Processes in Materials Science、Catalysis and Oxidation Reactions、Laser-induced spectroscopy and plasma

Surface properties of rare-earth (RE) doped ceria (RE = Sm, Gd, Pr, and Tb) were investigated by UV (325 nm) and visible (514, 633, and 785 nm) Raman spectroscopy, combined with UV-vis diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectra techniques. It was found that the optical absorption property of samples, the wavelength of detecting laser line, and the inhomogeneous distribution of the dopants significantly affected the obtained surface information, namely, the peak intensity and shape at ca. 460 and 570 cm(-1), as well as the observed oxygen vacancy concentration (A(570)/A(460)). The UV laser line detected the surface information of RE-doped ceria and disclosed the presence of many oxygen vacancies in the samples. The visible laser lines penetrated into the inner layer of the Sm- or Gd-doped CeO(2) and reflected the whole information of samples because of their weak absorptions of the visible laser. However, the Pr- or Tb-doped CeO(2) absorbed visible light strongly; thus, the laser can only determine the outer surface information of the sample.