Characterization of Silver Binding in Cryptomelane by X-ray Absorption Spectroscopy

1998 ◽  
Vol 524 ◽  
Author(s):  
R. Ravikumar ◽  
D. W. Fuerstenau ◽  
G. A. Waychunas
Keyword(s):  
Manganese Oxide ◽  
Silver Ions ◽  
Oxide Phase ◽  
Synthetic Sample ◽  
Temperature Spectrum ◽  
X Ray ◽  
Room Temperature Sample ◽  
X Ray Absorption ◽  
Temperature Sample

ABSTRACTUsing silver K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, two different samples of silver-containing manganese oxide were analyzed in the fluorescence mode. For the first sample, silver ions from solution were sorbed onto one synthetic manganese oxide phase, namely cryptomelane (KxMn8O16, where l<x<2). The second sample was a silvermanganese oxide from Colorado. From the EXAFS analysis, silver was found to occupy two different sites in the synthetic sample. The natural samples from Colorado also exhibited a very similar coordination distances as the synthetic samples. In the low temperature spectrum of the synthetic sample at 10 K, the Ag-O peak was found to be missing and the amplitude of the Ag- Ag peak was approximately three times larger than the corresponding room temperature sample.

EXELFS Studies of Carbon Fibers

1990 ◽  
Vol 48 (2) ◽  
pp. 72-73
Author(s):  
V. Serin ◽  
K. Hssein ◽  
G. Zanchi ◽  
J. Sévely
Keyword(s):  
Carbon Fibers ◽  
Energy Analysis ◽  
Electron Excitation ◽  
Complex Structures ◽  
High Modulus ◽  
Promising Technique ◽  
X Ray ◽  
Fine Structures ◽  
X Ray Absorption

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.

scholarly journals Database of ab initio L-edge X-ray absorption near edge structure

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yiming Chen ◽  
Chi Chen ◽  
Chen Zheng ◽  
Shyam Dwaraknath ◽  
Matthew K. Horton ◽  
...  
Keyword(s):  
High Throughput ◽  
Scattering Theory ◽  
Research Community ◽  
Metal Compounds ◽  
Edge Structure ◽  
X Ray ◽  
Initial Release ◽  
Computational Workflow ◽  
X Ray Absorption

AbstractThe L-edge X-ray Absorption Near Edge Structure (XANES) is widely used in the characterization of transition metal compounds. Here, we report the development of a database of computed L-edge XANES using the multiple scattering theory-based FEFF9 code. The initial release of the database contains more than 140,000 L-edge spectra for more than 22,000 structures generated using a high-throughput computational workflow. The data is disseminated through the Materials Project and addresses a critical need for L-edge XANES spectra among the research community.

Characterization of As-doped, p-type ZnO by x-ray absorption near-edge structure spectroscopy: Theory

2006 ◽  
Vol 89 (22) ◽  
pp. 222113 ◽  
Author(s):  
Sukit Limpijumnong ◽  
M. F. Smith ◽  
S. B. Zhang
Keyword(s):  
Edge Structure ◽  
X Ray ◽  
P Type ◽  
X Ray Absorption

The Experimental of Low Temperature Color Slip for Decorative on Earthenware Body

2016 ◽  
Vol 690 ◽  
pp. 282-285
Author(s):  
Soravich Mulinta
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Manganese Oxide ◽  
Ferric Oxide ◽  
Potassium Feldspar ◽  
Raw Material ◽  
Blue Color ◽  
X Ray ◽  
Yellow Color

The purpose of the study was to investigate the effects of dolomite body, frit and potassium feldspar on the properties of color slip for decorative method of color slip on earthen ware production. The characterization of raw material was analyzed by X-ray fluorescence (XRF). The experiment started with triaxial blend of dolomite body, frit and potassium feldspar in the defined ratio and then to painting of color slips on earthenware production. After that, firing specimens at 950 °C in oxidation atmosphere. Finally, the specimens were tested microstructure and physical properties. The results showed that the ratio of 50% dolomite body, 40% frit and 10% potassium feldspar were optimum properties for decorative on earthenware body. In color slip consisting of blue color added Cobalt oxide 1% ,Green colors added chromic oxide 10% , Gray color added manganese oxide 10% ,yellow color added stain 2225 10% and hazel color added ferric oxide 2 wt %.

LiMn2-xCuxO4 Spineis - 5 V Cathode Materials

1997 ◽  
Vol 496 ◽  
Author(s):  
Yair Ein-Eli ◽  
W. F. Howard ◽  
Sharon H. Lu ◽  
Sanjeev Mukerjee ◽  
James McBreen ◽  
...  
Keyword(s):  
Copper Ions ◽  
Oxide Phase ◽  
Electrochemical Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spinel Compounds ◽  
Composition And Structure ◽  
Phase Spinel ◽  
Lithium Copper Oxide ◽  
X Ray Absorption

ABSTRACTA series of electroactive spinel compounds, LiMn2-xCuxO4 (0.1 ≤ x ≤ 0.5) has been studied by crystallographic, spectroscopie and electrochemical methods and by electron-microscopy. These LiMn2-xCuxO4 spinels are nearly identical in structure to cubic LiMn2O4 and successfully undergo reversible Li intercalation. The electrochemical data show slight shifts to higher voltage for the delithiation reaction that normally occurs at 4.1 V in standard Li1−xMn2O4 electrodes (1 ≥ x ≥ 0) corresponding to the oxidation of Mn3+ to Mn4+. The data also show a remarkable reversible electrochemical process at 4.9 V which is attributed to the oxidation of Cu2+ to Cu3+. The inclusion of Cu in the spinel structure enhances the electrochemical stability of these materials upon cycling. The initial capacity of LiMn2-xCuxO4 spinels decreases with increasing x from 130 mAh/g in LiMn2O4 (x=0) to 70 mAh/g in “LiMn1.5Cu0.5O4”(x=0.5). Although the powder X-ray diffraction pattern of “LiMn1.5Cu0.5 O4” shows a single-phase spinel product, neutron diffraction data show a small, but significant quantity of an impurity phase, the composition and structure of which could not be identified. X-ray absorption spectroscopy was used to gather information about the oxidation states of the manganese and copper ions. The composition of the spinel component in the LiMn1.5Cu0.5O4 was determined from X-ray diffraction and XANES data to be Li1.01Mn1.67Cu0.32O4 suggesting, to a best approximation, that the impurity in the sample was a lithium-copper-oxide phase.

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