In Situ Characterization of Relevance of Surface Microstructure and Electrochemical Properties of Chalcopyrite to Adsorption of Acidianus manzaensis

2015 ◽  
Vol 1130 ◽  
pp. 183-187 ◽  
Author(s):  
Jin Lan Xia ◽  
Hong Rui Zhu ◽  
Lei Wang ◽  
Hong Chang Liu ◽  
Zhen Yuan Nie ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Electrochemical Treatment ◽  
Specific Adsorption ◽  
Initial Oxidation ◽  
Edge Structure ◽  
X Ray ◽  
Oxidation Potentials ◽  
Before And After ◽  
Acidianus Manzaensis

The in situ relevance of micro- structure and electrochemical properties of chalcopyrite to adsorption of thermoacidophilic bioleaching Archaea Acidianus manzaensis was studied. In this study, the electrochemical behavior of chalcopyrite was first investigated by cyclic voltammetry (CV) to get suitable initial reduction and oxidation potentials, at which electrochemical corrosions of chalcopyrite for several time were performed, respectively, to get specific surface micro-structures. The specific adsorption of A. manzaensis on the electrochemically corroded chalcopyrite surface was then comparatively studied. The changes of microstructure and chemical composition/speciation on the surface of chalcopyrite before and after electrochemical treatment and bio-adsorption was characterized by scanning electron microscopy/electron dispersive spectroscopy (SEM/EDS), and synchrotron radiation-based X-ray diffraction (SR-XRD) and Fe, Cu K-edge X-ray absorption near edge structure (XANES) spectroscopy. The results showed that the suitable initial oxidation and reduction of chalcopyrite electrode were at 0.67 V for 1h and -0.54 V for 10 min, respectively. After treated at 0.67V the surface of chalcopyrite became Cu-deficient with a composition of CuFe1.02S2.15, and bornite (Cu5FeS4) was detected. While after treated at -0.54V, the surface became Fe/S-deficient, with a composition of CuFe0.33S0.81, and a mass of chalcocite and some covellite were detected. Comparing to the original chalcopyrite, the adsorption capacity of A. manzaensis was increased on the surface of oxidation-treatment at 0.67 V, and decreased on the surface of reduction-treatment at -0.54 V. It clearly demonstrates the bornite-containing copper deficient chalcopyrite surface was more preferably adsorbed, whereas the chalcocite-containing Fe/S deficient chalcopyrite surface was less adsorbed by A. manzaensis, indicating the dependence of the specific adsorption of A. manzaensis upon the secondary minerals as well as Fe/S availability in the microstructure of chalcopyrite.

Probing Structure Modification of Palladium Nanomaterials during Chemical Synthesis by using In Situ X-ray Diffraction: Electrochemical Properties

2015 ◽  
Vol 2 (4) ◽  
pp. 592-599 ◽  
Author(s):  
Yaovi Holade ◽  
Teko W. Napporn ◽  
Claudia Morais ◽  
Karine Servat ◽  
K. Boniface Kokoh
Keyword(s):  
Chemical Synthesis ◽  
Electrochemical Properties ◽  
Structure Modification ◽  
X Ray Diffraction ◽  
X Ray

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.

scholarly journals In Situ Coherent X-ray Diffraction during Three-Point Bending of a Au Nanowire: Visualization and Quantification

2018 ◽  
Vol 2 (4) ◽  
pp. 24 ◽  
Author(s):  
Anton Davydok ◽  
Thomas Cornelius ◽  
Zhe Ren ◽  
Cedric Leclere ◽  
Gilbert Chahine ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Reciprocal Space ◽  
X Ray Diffraction ◽  
Complex Deformation ◽  
X Ray ◽  
Three Point Bending ◽  
Atomic Force ◽  
Au Nanowire ◽  
Before And After

The three-point bending behavior of a single Au nanowire deformed by an atomic force microscope was monitored by coherent X-ray diffraction using a sub-micrometer sized hard X-ray beam. Three-dimensional reciprocal-space maps were recorded before and after deformation by standard rocking curves and were measured by scanning the energy of the incident X-ray beam during deformation at different loading stages. The mechanical behavior of the nanowire was visualized in reciprocal space and a complex deformation mechanism is described. In addition to the expected bending of the nanowire, torsion was detected. Bending and torsion angles were quantified from the high-resolution diffraction data.

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.

In-Situ X-ray Diffraction Study of Lithium Intercalation in Nanostructured Anatase Titanium dioxide

1998 ◽  
Vol 536 ◽  
Author(s):  
R. Van de Krol ◽  
E. A. Meulenkamp ◽  
A. Goossens ◽  
J. Schoonman
Keyword(s):  
Phase Transformation ◽  
Maximum Amount ◽  
Lithium Intercalation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
The Difference ◽  
Two Phases ◽  
Reversible Phase

AbstractElectrochemical lithium intercalation in nanostructured anatase TiO2 is investigated with in-situ X-ray diffraction. A complete and reversible phase transformation from tetragonal anatase TiO2 to orthorhombic anatase Li0.5TiO2 is observed. The difference of the XRD spectra before and after insertion can be fitted with the lattice parameters of the two phases as fit parameters. The maximum amount of lithium that can be dissolved in anatase TiO2 before the phase transformation occurs is found to be very small.

The Application of In Situ 3D X-Ray Diffraction in Annealing Experiments: First Interpretation of Substructure Development in Deformed NaCl

2012 ◽  
Vol 715-716 ◽  
pp. 461-466 ◽  
Author(s):  
Verity Borthwick ◽  
Søren Schmidt ◽  
Sandra Piazolo ◽  
Carsten Gundlach ◽  
Albert Griera ◽  
...  
Keyword(s):  
Subgrain Boundary ◽  
Surface Effects ◽  
Sample Volume ◽  
European Synchrotron Radiation Facility ◽  
X Ray Diffraction ◽  
Boundary Misorientation ◽  
X Ray ◽  
Before And After ◽  
Annealing Experiments

n-situ 3D X-ray diffraction (3DXRD) annealing experiments were conducted at the ID-11 beamline at the European Synchrotron Radiation Facility in Grenoble. This allowed us to non-destructively document and subsequently analyse the development of substructures during heating, without the influence of surface effects. A sample of deformed single crystal halite was heated to between 260-400 °C. Before and after heating a volume of 500 by 500 by 300 μm was mapped using a planar beam, which was translated over the sample volume at intervals of 5-10 µm in the vertical dimension. In the following we present partially reconstructed orientation maps over one layer before and after heating for 240min at 260 °C. Additional small syn-heating maps over a constrained sample rotation of 12-30º. The purpose of this was to illuminate a few reflections from 1 or 2 subgrains and follow their evolution during heating. Preliminary results show that significant changes occurred within the sample volume, for which, surface effects can be excluded. Results show a number of processes, including: i) change in subgrain boundary misorientation angle and ii) subgrain subdivision into areas of similar lattice orientation with new subgrain boundary formation. These results demonstrate that 3DXRD coupled with in-situ heating is a successful non-destructive technique for examining real-time post-deformational annealing in strongly deformed crystalline materials with complicated microstructures.

Assessment of Cleaning Conservation Interventions on Architectural Surfaces Using an Integrated Methodology

2002 ◽  
Vol 712 ◽  
Author(s):  
Antonia Moropoulou ◽  
Ekaterini T. Delegou ◽  
Nicolas P. Avdelidis ◽  
Maria Koui
Keyword(s):  
Historic Buildings ◽  
X Ray Diffraction ◽  
Laboratory Methods ◽  
X Ray ◽  
Integrated Methodology ◽  
Physico Chemical ◽  
Before And After ◽  
Of Greece ◽  
Blasting Method

ABSTRACTIn this work, pilot cleaning interventions applied by a wet micro-blasting method on architectural surfaces of three historic buildings in marble and porous stone were evaluated in situ and in the laboratory. The investigation was performed on characteristic stone surfaces (marbles and porous stone) of the following historic buildings: Athens Academy and National Library of Greece in Athens center polluted urban environment and Bank of Greece in Piraeus marine environment. The materials of the facades were characterized, and the mechanism of decay was diagnosed. In addition, the cleaning method's efficiency was evaluated based on the acceptability of the alteration of the cleaned architectural surfaces. Criteria were both aesthetic and physico-chemical. In particular, the architectural surfaces were examined in situ by the means of fiber optic microscopy, infrared thermography and colorimetry. In the laboratory, methods of investigation were optical microscopy, X-ray diffraction, scanning electron microscopy with energy dispersion by X-ray analysis, mercury intrusion porosimetry, Fourier transform infrared spectroscopy, conductivity and pH measurements. The majority of measurements and analyses were applied before and after the pilot cleaning interventions. Finally, the results of this study contribute to the development of an integrated methodology for the assessment of cleaning interventions applied on architectural surfaces.

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