In Situ X‐Ray Absorption Near Edge Structure Study of the Potential Dependence of the Formation of the Passive Film on Iron in Borate Buffer

1997 ◽  
Vol 144 (7) ◽  
pp. 2398-2404 ◽  
Author(s):  
L. J. Oblonsky ◽  
A. J. Davenport ◽  
M. P. Ryan ◽  
H. S. Isaacs ◽  
R. C. Newman
2016 ◽  
Vol 1133 ◽  
pp. 429-433
Author(s):  
Siti Nooraya Mohd Tawil ◽  
Shuichi Emura ◽  
Daivasigamani Krishnamurthy ◽  
Hajime Asahi

Local structures around gadolinium atoms in rare-earth (RE)-doped InGaGdN thin films were studied by means of fluorescence extended X-ray absorption fine structure (EXAFS) measured at the Gd LIII-edges. The samples were doped with Gd in-situ during growth by plasma-assisted molecular beam epitaxy (PAMBE). Gd LIII-edge EXAFS signal from the GaGdN, GdN and Gd foil were also measured as reference. The X-ray absorption near edge structure (XANES) spectra around Gd LIII absorption edge of InGaGdN samples observed at room temperature indicated the enhancement of intensities with the increase of Gd composition. Further EXAFS analysis inferred that the Gd atoms in InGaN were surrounded by similar atomic shells as in the case of GaGdN with the evidence indicating majority of Gd atoms substituted into Ga sites of InGaGdN. A slight elongation of bond length for the 2nd nearest-neighbor (Gd–Ga) of sample with higher Gd concentration was also observed.


ChemInform ◽  
1989 ◽  
Vol 20 (48) ◽  
Author(s):  
J. MCBREEN ◽  
W. E. O'GRADY ◽  
G. TOURILLON ◽  
E. DARTYGE ◽  
A. FONTAINE ◽  
...  

2004 ◽  
Vol 59 (10-11) ◽  
pp. 1681-1686 ◽  
Author(s):  
Phil M. Oger ◽  
I. Daniel ◽  
B. Cournoyer ◽  
A. Simionovici

2015 ◽  
Vol 119 (34) ◽  
pp. 19573-19583 ◽  
Author(s):  
Dongniu Wang ◽  
Jigang Zhou ◽  
Yongfeng Hu ◽  
Jinli Yang ◽  
Na Han ◽  
...  

1989 ◽  
Vol 93 (17) ◽  
pp. 6308-6311 ◽  
Author(s):  
J. McBreen ◽  
W. E. O'Grady ◽  
G. Tourillon ◽  
E. Dartyge ◽  
A. Fontaine ◽  
...  

2015 ◽  
Vol 112 (52) ◽  
pp. 15803-15808 ◽  
Author(s):  
Ofer Hirsch ◽  
Kristina O. Kvashnina ◽  
Li Luo ◽  
Martin J. Süess ◽  
Pieter Glatzel ◽  
...  

The lanthanum-based materials, due to their layered structure and f-electron configuration, are relevant for electrochemical application. Particularly, La2O2CO3 shows a prominent chemoresistive response to CO2. However, surprisingly less is known about its atomic and electronic structure and electrochemically significant sites and therefore, its structure–functions relationships have yet to be established. Here we determine the position of the different constituents within the unit cell of monoclinic La2O2CO3 and use this information to interpret in situ high-energy resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) and valence-to-core X-ray emission spectroscopy (vtc XES). Compared with La(OH)3 or previously known hexagonal La2O2CO3 structures, La in the monoclinic unit cell has a much lower number of neighboring oxygen atoms, which is manifested in the whiteline broadening in XANES spectra. Such a superior sensitivity to subtle changes is given by HERFD method, which is essential for in situ studying of the interaction with CO2. Here, we study La2O2CO3-based sensors in real operando conditions at 250 °C in the presence of oxygen and water vapors. We identify that the distribution of unoccupied La d-states and occupied O p- and La d-states changes during CO2 chemoresistive sensing of La2O2CO3. The correlation between these spectroscopic findings with electrical resistance measurements leads to a more comprehensive understanding of the selective adsorption at La site and may enable the design of new materials for CO2 electrochemical applications.


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