scholarly journals Pre-edge Features of Ti K-edge X-ray Absorption Near-edge Structure for the Local Structure of Sol-Gel Titanium Oxides

2005 ◽  
Vol 21 (7) ◽  
pp. 805-809 ◽  
Author(s):  
Shuji MATSUO ◽  
Nahomi SAKAGUCHI ◽  
Hisanobu WAKITA



Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4061
Author(s):  
Yongtao Li ◽  
Liqing Liu ◽  
Dehao Wang ◽  
Hongguang Zhang ◽  
Xuemin He ◽  
...  

BiFeO3 is considered as a single phase multiferroic. However, its magnetism is very weak. We study the magnetic properties of BiFeO3 by Cu and (Cu, Zn). Polycrystalline samples Bi(Fe0.95Cu0.05)O3 and BiFe0.95(Zn0.025Cu0.025)O3 are prepared by the sol-gel method. The magnetic properties of BiFe0.95(Zn0.025Cu0.025)O3 are greater than that of BiFeO3 and Bi(Fe0.95Cu0.05)O3. The analyses of X-ray absorption fine structure data show that the doped Cu atoms well occupy the sites of the Fe atoms. X-ray absorption near edge spectra data confirm that the valence state of Fe ions does not change. Cu and Zn metal ion co-doping has no impact on the local structure of the Fe and Bi atoms. The modification of magnetism by doping Zn can be understood by the view of the occupation site of non-magnetically active Zn2+.



2013 ◽  
Vol 481 ◽  
pp. 133-136 ◽  
Author(s):  
T.N. Myasoedova ◽  
G.E. Yalovega ◽  
N.K. Plugotarenko ◽  
M. Brzhezinskaya ◽  
V.V. Petrov ◽  
...  

Copper oxides films as promising materials for gas sensors applications were studied. Copper oxide films were deposited onto Si/SiO2substrates using a citrate sol-gel method with the subsequent temperature treatment at 150-5000C. These films were characterized by means of secondary electron microscopy (SEM) and X-ray-absorption near-edge structure (XANES) spectroscopy. The prepared films were utilized in NO2sensors. The dependences of the NO2response on the operating temperature and NO2concentration (10-200 ppm) were investigated. The maximum NO2response was achieved for the film annealed at 2500C.



2015 ◽  
Vol 22 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Weiwei Gu ◽  
Hongxin Wang ◽  
Kun Wang

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2n(n= −2, −1, 0) (1,2,3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) (4) have been examined by NiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for1–3reveals clear pre-edge features and approximately +0.7 eV shift in the NiK-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni—S bond distances for1,2and3(2.11–2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in NiK-edge energy positions and Ni—S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni—C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct4presents no pre-edge feature, and its NiK-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex3. Consistently, EXAFS also showed that the Ni—S distances in4elongate by ∼0.046 Å in comparison with3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of3as suggested by UV/visible spectroscopy in the literature.



1996 ◽  
Vol 11 (9) ◽  
pp. 2242-2256 ◽  
Author(s):  
T. Jiang ◽  
D. E. Ellis

Theoretical studies have been made of K-edge x-ray absorption near edge structure (XANES) of Co in CoO, Co(OH)2, CoTiO3, Co3O4, and CoAl2O4. Correlations of experimental near edge features with site symmetry, local geometry, local electronic structure, i.e., atomic configuration, charge transfer, and backscattering from neighboring atomic potentials are interpreted. The self-consistent Discrete Variational Xa Method (DV-Xα) within an embedded cluster technique has been used to generate the crystal potential. A multiple scattering (MS) approach is then used to solve for the final state wave function. The ground state DV wave functions are analyzed in terms of the projected density of states, whereas the final state MS continuum wave functions are analyzed through the concept of photoelectron trapping time.



2016 ◽  
Vol 18 (29) ◽  
pp. 19621-19630 ◽  
Author(s):  
Janis Timoshenko ◽  
Atal Shivhare ◽  
Robert W. J. Scott ◽  
Deyu Lu ◽  
Anatoly I. Frenkel

XANES analysis guided by ab initio modeling is proposed for refinement of local environments around metal impurities in heterogeneous catalysts.



2005 ◽  
Vol 480-481 ◽  
pp. 21-26 ◽  
Author(s):  
L.J. Skipper ◽  
F.E. Sowrey ◽  
D.M. Pickup ◽  
R.J. Newport ◽  
K.O. Drake ◽  
...  

The formation of a carbonate-containing hydroxyapatite, HCAp, layer on bioactive calcium silicate sol-gel glass of the formula (CaO)0.3(SiO2)0.7 has been studied in-vitro in Simulated Body Fluid (SBF). Extended X-ray Absorption Fine Structure (EXAFS), X-ray Absorption Near Edge Structure (XANES), X-ray diffraction (XRD), and solid state nuclear magnetic resonance (NMR) measurements have been performed with results showing the formation of a significantly amorphous HCAp layer after less than 5 hours in solution.



2015 ◽  
Vol 119 (15) ◽  
pp. 8070-8077 ◽  
Author(s):  
Hiroyuki Asakura ◽  
Tetsuya Shishido ◽  
Kentaro Teramura ◽  
Tsunehiro Tanaka


2020 ◽  
Vol 22 (34) ◽  
pp. 18902-18910 ◽  
Author(s):  
Nicholas Marcella ◽  
Yang Liu ◽  
Janis Timoshenko ◽  
Erjia Guan ◽  
Mathilde Luneau ◽  
...  

Trained neural networks are used to extract the first partial coordination numbers from XANES spectra. In bimetallic nanoparticles, the four local structure descriptors provide rich information on structural motifs.





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