UV and Visible Raman Studies of Oxygen Vacancies in Rare-Earth-Doped Ceria.
Summary of "UV and Visible Raman Studies of Oxygen Vacancies in Rare-Earth-Doped Ceria."
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.
Affiliation
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University , Jinhua 321004, China.
Journal Details
This article was published in the following journal.
Name: Langmuir : the ACS journal of surfaces and colloids
ISSN: 1520-5827
Pages: 3872-7
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21395268
- DOI: http://dx.doi.org/10.1021/la200292f
Medical and Biotech [MESH] Definitions
Lasers, Solid-state
Lasers which use a solid, as opposed to a liquid or gas, as the lasing medium. Common materials used are crystals, such as YAG (YTTRIUM aluminum garnet); alexandrite; and CORUNDUM, doped with a rare earth element such as a NEODYMIUM; ERBIUM; or HOLMIUM. The output is sometimes additionally modified by addition of non-linear optical materials such as potassium titanyl phosphate crystal, which for example is used with neodymium YAG lasers to convert the output light to the visible range.
Metals, Rare Earth
A group of elements that include SCANDIUM; YTTRIUM; and the LANTHANOID SERIES ELEMENTS. Historically, the rare earth metals got their name from the fact that they were never found in their pure elemental form, but as an oxide. In addition they were very difficult to purify. They are not truly rare and comprise about 25% of the metals in the earth's crust.
Spectrum Analysis, Raman
Analysis of the intensity of Raman scattering of monochromatic light as a function of frequency of the scattered light.
Earth Sciences
Fields of science encompassing studies and research from the disciplines of PHYSICS; CHEMISTRY; BIOLOGICAL SCIENCES; and MATHEMATICS; that are related to the planet EARTH. Subfields include atmospheric chemistry; CLIMATOLOGY; ENVIRONMENTAL SCIENCES; GEOGRAPHY; GEOLOGY; geophysics; METEOROLOGY; OCEANOGRAPHY; PALEONTOLOGY; mineralogy; and seismology.
Yttrium
An element of the rare earth family of metals. It has the atomic symbol Y, atomic number 39, and atomic weight 88.91. In conjunction with other rare earths, yttrium is used as a phosphor in television receivers and is a component of the yttrium-aluminum garnet (YAG) lasers.
PubMed Articles
Defect clustering and local ordering in rare earth co-doped ceria.
Defect clustering and local ordering in rare earth co-doped ceria were studied by computer simulation and electron diffraction, respectively. The simulation of electrically neutral defect clusters con...
Nitrogen-doped TiO(2) thin films: photocatalytic applications for healthcare environments.
N-doped TiO(2) has for many years received interest as visible light photocatalytic materials. Here we give our perspective on the subject with special consideration towards the use of visible light p...
The Influence of Defects on Mo-Doped TiO(2) by First-Principles Studies.
TiO(2) doped with transition metals shows improved photocatalytic efficiency. Herein the electronic and optical properties of Mo-doped TiO(2) with defects are investigated by DFT calculations. For bot...
The electronic structure and photoactivation process in N-doped TiO(2) is investigated. Diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and electron paramagnetic resonance (EPR) are em...
Comparative Study of CeO(2) and Doped CeO(2) with Tailored Oxygen Vacancies for CO Oxidation.
We report on the preparation and characterization of CeO(2) nanofibers (CeO(2) -NFs) and nanocubes (CeO(2) -NCs), as well as Sm- and Gd-doped CeO(2) nanocubes (Sm-CeO(2) -NCs and Gd-CeO(2) -NCs), sy...
Clinical Trials
Effect of High Levels of Oxygen and Smoking on the Lungs in Human Volunteers
Patients with lung disease experiencing difficulty breathing can be treated with oxygen therapy. This involves the delivery of "extra" oxygen by a face-mask or through small tubes placed...
Oxygen Portable Concentrator During Exercises in Patients With COPD
The purpose of this study is to compare differences in oxygen delivery between portable oxygen concentrators (POCs) and liquid oxygen (LOs) portable units, pose a question if POCs are equa...
This study will describe the experience of patients with visible physical abnormalities in the genetics clinic when they are involved in teaching others about their condition. Information...
Traumatic brain injuries (TBI) are a major cause of morbidity and mortality worldwide. Due to improvements in emergency medical care, transportation and specialized trauma facilities, the...
Pre-flight Titration of Supplemental Oxygen
The purpose of this study is to evaluate if supplemental oxygen during air travel can be reliably titrated using a Hypoxia-altitude simulation test (HAST). Also, the effect of oxygen suppl...
