Topic
XANES
About: XANES is a research topic. Over the lifetime, 7737 publications have been published within this topic receiving 188032 citations.
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TL;DR: In this paper, the behavior of all major sulfur forms during in situ high-temperature oxidation and pyrolysis was derived for two US bituminous coals and a low-rank Australian brown coal from least-squares analysis of sulfur K-edge X-ray absorption nearedge structure spectra taken at constant temperatures up to 600°C.
Abstract: Sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy has been utilized to conduct the first direct characterization and quantification of sulfur functional groups in coal during in situ high-temperature oxidation and pyrolysis. The behavior of all major sulfur forms during such treatments was derived for two US bituminous coals and a low-rank Australian brown coal from least-squares analysis of sulfur K-edge XANES spectra taken at constant temperatures up to 600°C. During pyrolysis, pyrite began to convert to pyrrhotite at temperatures above 400°C
70 citations
TL;DR: In this paper, the structural and magnetic properties of cobalt ferrite produced by sol-gel and by ball milling methods were studied with X-ray absorption near-edge structure (XANES) spectroscopy and Xray emission spectro-graphs (XES).
70 citations
TL;DR: In this article, the HDS of thiophene was studied over Ni 2 P/MCM-41 by in situ Fourier transform infrared (FTIR) spectroscopy and X-ray absorption near-edge structure (XANES) measurements at atmospheric pressure and 393 −723 −K (120 −450 −C).
70 citations
TL;DR: In this article, the photoluminescence properties of the Eu3+ ions in CaWO4 were studied as well as the chromaticity coordinates and lifetimes of these compounds.
Abstract: CaWO4:Eu3+ microcrystals (with 0, 1, 2 and 4 mol% Eu3+) were synthesized by a co-precipitation (CP) method and grown in a microwave-assisted hydrothermal (MAH) system at 130 °C for 30 min. X-ray diffraction (XRD), Rietveld refinement, X-ray absorption near edge spectroscopy (XANES), Fourier-transform Raman (FT-Raman) and Fourier-transform infrared (FT-IR) spectroscopy indicated that all of the microcrystals have a scheelite-type tetragonal structure without deleterious phases. Structural refinement data were employed to model the [CaO8], [EuO8] and [WO4] clusters. XANES spectra confirmed that the presence of deltahedral [EuO8] clusters promotes small distortions of neighbouring tetrahedral [WO4] clusters in a global tetragonal lattice. Field emission scanning electron microcopy (FE-SEM) images revealed that the replacement of Ca2+ by Eu3+ ions changed the particles' shapes, resulting in the different morphologies of the microcrystals. UV-vis diffuse reflectance spectra indicated a reduction in the optical band gap with the replacement of Ca2+ by Eu3+ ions. The photoluminescence (PL) properties of the Eu3+ ions in CaWO4 were studied as well as the chromaticity coordinates and lifetimes of these compounds.
70 citations
TL;DR: Combined EXAFS and XANES observations suggested that chemical reactions such as hydroxylation of CuCl2 and oxidation of Cu2O and/or metallic Cu might involve in the solidification process, which also led to a significant reduction of the leachability of copper from the solidified fly ashes.
Abstract: Speciation of copper in the fly ash solidification process has been studied by X-ray based spectroscopies in the present work. Fourier transformed EXAFS (extended X-ray absorption fine structural) spectra of the solidified fly ashes showed that the bond distance of Cu−O (first shell) was 1.96 A with a coordination number (CN) of about 3.0. However, in the second shell of copper atoms, the bond distance of Cu−(O)−Cu was decreased by 0.12−0.22 A during solidification, which might cause the stabilization of the CuO species in the solidified fly ash matrix. By the least-squares fits of the XANES (X-ray absorption near edge structural) spectra, fractions of the main copper species in the solidified fly ashes such as CuCl2 (0.08−0.11), Cu2O (0.07−0.09), Cu(OH)2 (0.31−0.33), and CuO (0.49−0.52) were observed. Combined EXAFS and XANES observations suggested that chemical reactions such as hydroxylation of CuCl2 and oxidation of Cu2O and/or metallic Cu might involve in the solidification process, which also led to...
70 citations