In Situ Heater Design for Nanoscale Synchrotron-Based Full-Field Transmission X-Ray Microscopy

2015 ◽  
Vol 21 (2) ◽  
pp. 290-297 ◽  
Author(s):  
Andrew M. Kiss ◽  
William M. Harris ◽  
Arata Nakajo ◽  
Steve Wang ◽  
Joan Vila-Comamala ◽  
...  
Keyword(s):  
Chemical Conversion ◽  
Operating Conditions ◽  
Edge Structure ◽  
Full Field ◽  
X Ray ◽  
Unreacted Core Model ◽  
Working Distance ◽  
Heater Design ◽  
X Ray Absorption

AbstractThe oxidation of nickel powder under a controlled gas and temperature environment was studied using synchrotron-based full-field transmission X-ray microscopy. The use of this technique allowed for the reaction to be imaged in situ at 55 nm resolution. The setup was designed to fit in the limited working distance of the microscope and to provide the gas and temperature environments analogous to solid oxide fuel cell operating conditions. Chemical conversion from nickel to nickel oxide was confirmed using X-ray absorption near-edge structure. Using an unreacted core model, the reaction rate as a function of temperature and activation energy were calculated. This method can be applied to study many other chemical reactions requiring similar environmental conditions.

Full-Field Calcium K-Edge X-ray Absorption Near-Edge Structure Spectroscopy on Cortical Bone at the Micron-Scale: Polarization Effects Reveal Mineral Orientation

2016 ◽  
Vol 88 (7) ◽  
pp. 3826-3835 ◽  
Author(s):  
Bernhard Hesse ◽  
Murielle Salome ◽  
Hiram Castillo-Michel ◽  
Marine Cotte ◽  
Barbara Fayard ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Edge Structure ◽  
Full Field ◽  
Polarization Effects ◽  
X Ray ◽  
X Ray Absorption

scholarly journals High-energy resolution X-ray absorption and emission spectroscopy reveals insight into unique selectivity of La-based nanoparticles for CO2

2015 ◽  
Vol 112 (52) ◽  
pp. 15803-15808 ◽  
Author(s):  
Ofer Hirsch ◽  
Kristina O. Kvashnina ◽  
Li Luo ◽  
Martin J. Süess ◽  
Pieter Glatzel ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Emission Spectroscopy ◽  
High Energy ◽  
Unit Cell ◽  
High Energy Resolution ◽  
Electron Configuration ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

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.

Fluorescence Extended X-Ray Absorption Fine Structure Study on Local Structures of Rare-Earth-Doped InGaGdN

2016 ◽  
Vol 1133 ◽  
pp. 429-433
Author(s):  
Siti Nooraya Mohd Tawil ◽  
Shuichi Emura ◽  
Daivasigamani Krishnamurthy ◽  
Hajime Asahi
Keyword(s):  
Fine Structure ◽  
Rare Earth ◽  
Nearest Neighbor ◽  
Structure Study ◽  
Edge Structure ◽  
X Ray ◽  
Local Structures ◽  
Absorption Fine ◽  
X Ray Absorption

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.

In situ XANES Study of Co2+ Ion Adsorption on Fe3O4 Nanoparticles in Supercritical Aqueous Fluids

2012 ◽  
Vol 1383 ◽  
Author(s):  
Hao Yan ◽  
Robert A. Mayanovic ◽  
Joseph Demster ◽  
Alan J. Anderson
Keyword(s):  
Angular Momentum ◽  
Density Of States ◽  
Fe3o4 Nanoparticles ◽  
Ion Adsorption ◽  
Edge Structure ◽  
X Ray ◽  
Peak Fitting ◽  
X Ray Absorption ◽  
In Situ Xanes

ABSTRACTIn situ x-ray absorption spectroscopy (XAS) measurements were made on Fe3O4 nanoparticles in supercritical aqueous fluids to 500 °C in order to study their reactivity with Co2+ aqua ions and to investigate the structural properties of the reacted nanoparticles. The analyses of the x-ray absorption near edge structure (XANES) of XAS indicate that reactivity of Fe3O4 nanoparticles with Co2+ ions is minimal to 200 °C but becomes significant in the 250–500 °C temperature range. XANES and angular momentum projected density of states (l-DOS) calculations were carried out using the FEFF8.2 code and analyses were made using multi-peak fitting to determine the origin of the features exhibited in the spectra.

scholarly journals Application toward Confocal Full-Field Microscopic X-ray Absorption Near Edge Structure Spectroscopy

2017 ◽  
Vol 89 (3) ◽  
pp. 2123-2130 ◽  
Author(s):  
Pieter Tack ◽  
Bart Vekemans ◽  
Brecht Laforce ◽  
Jennifer Rudloff-Grund ◽  
Willinton Y. Hernández ◽  
...  
Keyword(s):  
Edge Structure ◽  
Full Field ◽  
X Ray ◽  
X Ray Absorption

scholarly journals In situ X-Ray Absorption Near-Edge Structure Spectroscopy Reveals Arsenic Ligation in Rice

2020 ◽  
Author(s):  
Benjamin Bostick ◽  
Yating Shen ◽  
Elizabeth Wiita ◽  
Athena Nghiem ◽  
Jingyu Liu ◽  
...  
Keyword(s):  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals In situ X-ray absorption spectroscopic studies of TiO2 photocatalytic active sites for degradation of trace CHCl3 in drinking water

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
T.-L. Hsiung ◽  
L.-W. Wei ◽  
H.-L. Huang ◽  
H. Paul Wang
Keyword(s):  
Drinking Water ◽  
Photocatalytic Degradation ◽  
Active Sites ◽  
Spectroscopic Studies ◽  
Band Gap Energy ◽  
Disinfection Byproducts ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Toxic disinfection byproducts such as trihalomethanes (e.g. CHCl3) are often found after chlorination of drinking water. It has been found that photocatalytic degradation of trace CHCl3 in drinking water generally lacks an expected relationship with the crystalline phase, band-gap energy or the particle sizes of the TiO2-based photocatalysts used such as nano TiO2 on SBA-15 (Santa Barbara amorphous-15), TiO2 clusters (TiO2–SiO2) and atomic dispersed Ti [Ti-MCM-41 (Mobil Composition of Matter)]. To engineer capable TiO2 photocatalysts, a better understanding of their photoactive sites is of great importance and interest. Using in situ X-ray absorption near-edge structure (XANES) spectroscopy, the A1 (4969 eV), A2 (4971 eV) and A3 (4972 eV) sites in TiO2 can be distinguished as four-, five- and six- coordinated Ti species, respectively. Notably, the A2 Ti sites that are the main photocatalytic species of TiO2 are shown to be accountable for about 95% of the photocatalytic degradation of trace CHCl3 in drinking water (7.2 p.p.m. CHCl3 gTiO2 −1 h−1). This work reveals that the A2 Ti species of a TiO2-based photocatalyst are mainly responsible for the photocatalytic reactivity, especially in photocatalytic degradation of CHCl3 in drinking water.

scholarly journals A compact furnace for in situ X-ray absorption spectroscopy: design, fabrication and study of cationic oxidation states in Pr6O11 and NiO

2021 ◽  
Vol 28 (2) ◽  
pp. 455-460
Author(s):  
Suchinda Sattayaporn ◽  
Somboonsup Rodporn ◽  
Pinit Kidkhunthod ◽  
Narong Chanlek ◽  
Chutarat Yonchai ◽  
...  
Keyword(s):  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Heating Temperature ◽  
Reduction Process ◽  
Oxidation States ◽  
Quartz Tube ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

A well designed compact furnace has been designed for in situ X-ray absorption spectroscopy (XAS). It enables various heat ramps from 300 K to 1473 K. The furnace consists of heaters, a quartz tube, a circulated refrigerator and a power controller. It can generate ohmic heating via an induction process with tantalum filaments. The maximum heating rate exceeds 20 K min−1. A quartz tube with gas feedthroughs allows the mixing of gases and adjustment of the flow rate. The use of this compact furnace allows in situ XAS investigations to be carried out in transmission or fluorescence modes under controlled temperature and atmosphere. Moreover, the furnace is compact, light and well compatible to XAS. The furnace was used to study cationic oxidation states in Pr6O11 and NiO compounds under elevated temperature and reduced atmosphere using the in situ X-ray absorption near-edge structure (XANES) technique at beamline 5.2 SUT-NANOTEC-SLRI of the Synchrotron Light Research Institute, Thailand. At room temperature, Pr6O11 contains a mixture of Pr3+ and Pr4+ cations, resulting in an average oxidation state of +3.67. In situ XANES spectra of Pr (L 3-edge) show that the oxidation state of Pr4+ cations was totally reduced to +3.00 at 1273 K under H2 atmosphere. Considering NiO, Ni2+ species were present under ambient conditions. At 573 K, the reduction process of Ni2+ occurred. The Ni0/Ni2+ ratio increased linearly with respect to the heating temperature. Finally, the reduction process of Ni2+ was completely finished at 770 K.

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