scholarly journals In Situ Dispersive EXAFS in Electrocatalysis: The Investigation of the Local Structure of IrOxin Chronoamperometric Conditions as a Case Study

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Elisabetta Achilli ◽  
Alessandro Minguzzi ◽  
Ottavio Lugaresi ◽  
Cristina Locatelli ◽  
Sandra Rondinini ◽  
...  
Keyword(s):  
Fourier Transforms ◽  
Point Of View ◽  
General Point ◽  
Time Resolved ◽  
Electrochemical Processes ◽  
In Situ Experiments ◽  
X Ray Absorption ◽  
Short Range Structure

An in situ study with dispersive EXAFS (Extended X-Ray Absorption Spectroscopy) at the Ir-LIIIedge is performed to characterize Electrodeposited Iridium Oxide Films (EIROF) under chronoamperometric conditions. The technique monitors the local chemical environment and electronic structure of iridium during the oxidation of Ir(III) to Ir(IV) with a time resolution of milliseconds. The study is performed in both acidic and basic media. The Fourier transforms of the time-resolved EXAFS signals clearly show that the short-range structure of Ir is similar to that of rutile-type IrO2and is maintained during the reaction, thus accounting for the flexibility of the structure of the electrode material in accommodating different oxidation states. From a more general point of view, the work demonstrates the capabilities of in situ experiments based on state-of-the-art dispersive EXAFS in clarifying the mechanistic aspects of electrochemical processes.

scholarly journals Stoichiometry and disorder influence over electronic structure in nanostructured VOx films

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
A. D’Elia ◽  
S. J. Rezvani ◽  
N. Zema ◽  
F. Zuccaro ◽  
M. Fanetti ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Distorted Octahedral Geometry ◽  
Edge Structure ◽  
Distorted Octahedral ◽  
X Ray Absorption ◽  
Complex Matter ◽  
Nanometric Size

AbstractWe present and discuss the role of nanoparticles size and stoichiometry over the local atomic environment of nanostructured VOx films. The samples have been characterized in situ using X-ray absorption near-edge structure (XANES) spectroscopy identifying the stoichiometry-dependent fingerprints of disordered atomic arrangement. In vanadium oxides, the ligand atoms arrange according to a distorted octahedral geometry depending on the oxidation state, e.g. trigonal distortion in V2O3 and tetragonal distortion in bulk VO2. We demonstrate, taking VO2 as a case study, that as a consequence of the nanometric size of the nanoparticles, the original ligands symmetry of the bulk is broken resulting in the coexistence of a continuum of distorted atomic conformations. The resulting modulation of the electronic structure of the nanostructured VOx as a function of the oxygen content reveals a stoichiometry-dependent increase of disorder in the ligands matrix. This work shows the possibility to produce VOx nanostructured films accessing new disordered phases and provides a unique tool to investigate the complex matter.

Pulsed Microwave Processing of High-TC Superconducting Films

1992 ◽  
Vol 269 ◽  
Author(s):  
R. B. James ◽  
R. A. Alvarez ◽  
A. K. Stamper ◽  
X. J. Bao ◽  
T. E. Schlesinger ◽  
...  
Keyword(s):  
Phase Transition ◽  
Barium Copper Oxide ◽  
Precursor Film ◽  
Silicon Substrates ◽  
Molten Layer ◽  
Time Resolved ◽  
Barium Copper ◽  
In Situ Experiments ◽  
Yttrium Barium

ABSTRACTWe have used 2.0-μsec microwave pulses at a frequency of 2.856 GHz to rapidly heat thin amorphous yttrium-barium-copper-oxide (YBCO) films deposited onto silicon substrates. The samples were irradiated inside a WR-284 waveguide by single-pass TE10 pulses in a traveling wave geometry. X-ray diffractometry studies show that an amorphous-to-crystalline phase transition occurs for incident pulse powers exceeding about 6 MW, in which case the amorphous YBCO layer is converted to Y2BaCuO5. Microscopy of the irradiated film reveals that the phase transition is brought about by melting of the YBCO precursor film and crystallization of the molten layer upon solidification. Time-resolved in situ experiments of the microwave reflectivity (R) and transmissivity (T) show that there is an abrupt change in R for microwave pulse powers exceeding the melt threshold, so that measurements of R and T can be used to monitor the onset of surface melting.

scholarly journals Numerical Evaluation of Slender Glass Panel with Complex Geometry Subjected to Static Load and Soft-body Impact

2021 ◽  
Author(s):  
Marcin Kozłowski
Keyword(s):  
Static Load ◽  
Complex Geometry ◽  
Design Practice ◽  
Glass Panel ◽  
Soft Body ◽  
In Situ Experiments ◽  
Glass Panels ◽  
Current Standards

Current standards and glass codes of design practice require that glazing used in architectural applications has to be resistant to, in addition to typical loads, also accidental events, in particular human impact, without showing damage that is disproportionate to the original cause. A case study was performed of an indoor glass lantern in a public building made from slender two-side supported glass panels with a complex geometry (36 ventilation holes). The paper provides structural assessments and results of in-situ experiments including static loading and soft body impact. Results from numerical simulations of impact loading on the glass panels complementing the experimental results are also presented.

scholarly journals On the mechanism of rapid metal exchange between thiolate-protected gold and gold/silver clusters: a time-resolved in situ XAFS study

2018 ◽  
Vol 20 (7) ◽  
pp. 5312-5318 ◽  
Author(s):  
Bei Zhang ◽  
Olga V. Safonova ◽  
Stephan Pollitt ◽  
Giovanni Salassa ◽  
Annelies Sels ◽  
...  
Keyword(s):  
Exchange Reaction ◽  
Silver Clusters ◽  
Metal Exchange ◽  
Time Resolved ◽  
X Ray ◽  
Gold Silver ◽  
In Situ Xafs ◽  
Metal Exchange Reaction ◽  
X Ray Absorption

The fast metal exchange reaction between Au38 and AgxAu38−x nanoclusters has been studied by time resolved in situ X-ray absorption spectroscopy.

scholarly journals Tandem X-ray absorption spectroscopy and scattering for in situ time-resolved monitoring of gold nanoparticle mechanosynthesis

2020 ◽  
Vol 56 (71) ◽  
pp. 10329-10332 ◽  
Author(s):  
Paulo F. M. de Oliveira ◽  
Adam A. L. Michalchuk ◽  
Ana Guilherme Buzanich ◽  
Ralf Bienert ◽  
Roberto M. Torresi ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Absorption Spectroscopy ◽  
Mechanochemical Synthesis ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Absorption

A new tandem approach combines XRD and XANES for time-resolved in situ monitoring of the mechanochemical synthesis of gold nanoparticles.

In situ time resolved studies of hydride and deuteride formation in Pd/C electrodes via energy dispersive X-ray absorption spectroscopy

2005 ◽  
Vol 7 (2) ◽  
pp. 366-372 ◽  
Author(s):  
A. Rose ◽  
O. South ◽  
I. Harvey ◽  
S. Diaz-Moreno ◽  
J. R. Owen ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Energy Dispersive ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Absorption

X-Ray Absorption Spectroscopy as an in-situ Tool in Materials Science

1997 ◽  
Vol 502 ◽  
Author(s):  
T. Ressler ◽  
Joe Wong ◽  
W. Metz
Keyword(s):  
Absorption Spectroscopy ◽  
Materials Science ◽  
Ex Situ ◽  
Structural Studies ◽  
Time Resolved ◽  
X Ray ◽  
Complementary Techniques ◽  
X Ray Absorption ◽  
Established Technique

ABSTRACTIn addition to being an established technique for ex-situ structural studies, x-ray absorption spectroscopy (XAS) has recently been realized to be a powerful tool for in-situ time-resolved investigations in materials science. This paper describes two complementary techniques: quick-scanning EXAFS (QEXAFS) and energy-dispersive XAS (DXAS) which offer time resolution in the seconds and milliseconds range, respectively. Formation of a heterogeneous catalyst from a solid-state reaction of a precursor is presented as an example of a time-resolved XAS application.

scholarly journals In situ time-resolved dispersive X-ray absorption fine structure analysis of BaTiO3–LiCoO2 composites for lithium ion batteries

2016 ◽  
Vol 124 (6) ◽  
pp. 659-663 ◽  
Author(s):  
Takashi TERANISHI ◽  
Yumi YOSHIKAWA ◽  
Ryota MIYAHARA ◽  
Hidetaka HAYASHI ◽  
Akira KISHIMOTO ◽  
...  
Keyword(s):  
Fine Structure ◽  
Lithium Ion Batteries ◽  
Structure Analysis ◽  
Lithium Ion ◽  
Time Resolved ◽  
X Ray ◽  
Absorption Fine ◽  
Fine Structure Analysis ◽  
X Ray Absorption
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