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Journal articles on the topic 'Spectroscopie Mössbauer in situ'

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Published: 4 June 2021

Last updated: 4 May 2024

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1

Fleischer, Iris, Göstar Klingelhöfer, Richard V. Morris, Christian Schröder, Daniel Rodionov, and Paulo A. de Souza. "In-situ Mössbauer spectroscopy with MIMOS II." Hyperfine Interactions 207, no. 1-3 (November 1, 2011): 97–105. http://dx.doi.org/10.1007/s10751-011-0437-y.

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2

BIBICU, ION. "Nanomaterials characterization by Mössbauer spectroscopy." Journal of Engineering Sciences and Innovation 3, no. 3 (September 16, 2018): 239–50. http://dx.doi.org/10.56958/jesi.2018.3.3.239.

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Mössbauer spectroscopy has one of its most important features the ability to undertake bulk of varying thickness using the secondary radiation emitted after resonant absorption of a gamma ray. Using emitted electrons it is possible to characterize the nanomaterials. It is a non-destructive technique that can be applied in situ investigations. A short description of the technique is given. The author presents the detectors achieved for these studies and the principal results in nanomaterial characterization. Few results are described more detailed.

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3

Loup, Joachim, Tobias Parchomyk, Stefan Lülf, Serhiy Demeshko, Franc Meyer, Konrad Koszinowski, and Lutz Ackermann. "Mössbauer and mass spectrometry support for iron(ii) catalysts in enantioselective C–H activation." Dalton Transactions 48, no. 16 (2019): 5135–39. http://dx.doi.org/10.1039/c9dt00705a.

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A combination of electrospray-ionization mass spectrometry and Mössbauer spectroscopy was used to investigate the species generated in situ in highly enantioselective Fe/NHC-catalyzed C–H alkylations.

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4

Dräger, Christoph, Florian Sigel, Ralf Witte, Robert Kruk, Lukas Pfaffmann, Stefan Mangold, Valeriu Mereacre, Michael Knapp, Helmut Ehrenberg, and Sylvio Indris. "Observation of electrochemically active Fe3+/Fe4+ in LiCo0.8Fe0.2MnO4 by in situ Mössbauer spectroscopy and X-ray absorption spectroscopy." Physical Chemistry Chemical Physics 21, no. 1 (2019): 89–95. http://dx.doi.org/10.1039/c8cp06177g.

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5

Clausen, Bjerne S., and Henrik TopsØe. "In-situ studies of catalysts by XAFS and Mössbauer spectroscopy." Hyperfine Interactions 47-48, no. 1-4 (March 1989): 203–17. http://dx.doi.org/10.1007/bf02351608.

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6

Fournes, L., J.-C. Grenier, C. Chanson, P. Bezdicka, A. Wattiaux, and M. Pouchard. "Use of in situ Mössbauer spectroscopy for electrochemical reactions involving57Fe." Hyperfine Interactions 57, no. 1-4 (July 1990): 1829–32. http://dx.doi.org/10.1007/bf02405729.

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7

Dézsi, I., and Cs Fetzer. "In situ study of electrodeposited thin layers by Mössbauer spectroscopy." Electrochemistry Communications 9, no. 7 (July 2007): 1846–49. http://dx.doi.org/10.1016/j.elecom.2007.04.007.

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8

Aldon, Laurent, and Alexis Perea. "2D-correlation analysis applied to in situ and operando Mössbauer spectroscopy." Journal of Power Sources 196, no. 3 (February 2011): 1342–48. http://dx.doi.org/10.1016/j.jpowsour.2010.08.013.

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9

Fleischer, I., G. Klingelhöfer, F. Rull, S. Wehrheim, S. Ebert, M. Panthöfer, M. Blumers, D. Schmanke, J. Maul, and C. Schröder. "In-situ Mössbauer Spectroscopy with MIMOS II at Rio Tinto, Spain." Journal of Physics: Conference Series 217 (March 1, 2010): 012062. http://dx.doi.org/10.1088/1742-6596/217/1/012062.

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10

Ksenofontov, V., S. Reiman, M. Waldeck, R. Niewa, R. Kniep, and P. Gütlich. "In situ— High Temperature Mössbauer Spectroscopy of Iron Nitrides and Nitridoferrates." Zeitschrift für anorganische und allgemeine Chemie 629, no. 10 (September 2003): 1787–94. http://dx.doi.org/10.1002/zaac.200300135.

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11

Aboulaich, Abdelmaula, Florent Robert, Pierre Emmanuel Lippens, Laurent Aldon, Josette Olivier-Fourcade, Patrick Willmann, and Jean-Claude Jumas. "In situ 119Sn Mössbauer spectroscopy study of Sn-based electrode materials." Hyperfine Interactions 167, no. 1-3 (November 8, 2006): 733–38. http://dx.doi.org/10.1007/s10751-006-9358-6.

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12

Marras, Giulia, Gabriele Carnevale, Antonio Caracausi, Silvio Giuseppe Rotolo, and Vincenzo Stagno. "First measurements of the Fe oxidation state of spinel inclusions in olivine single crystals from Vulture (Italy) with the in situ synchrotron micro-Mössbauer technique." European Journal of Mineralogy 35, no. 4 (August 21, 2023): 665–78. http://dx.doi.org/10.5194/ejm-35-665-2023.

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Abstract. The redox state of the Earth's upper mantle (i.e., oxygen fugacity, fO2) is a key variable that influences numerous processes occurring at depth like the mobility of volatile species, partial melting, and metasomatism. It is linked to the oxidation state of peridotite rocks, which is normally determined through the available oxythermobarometers after measuring the chemical composition of equilibrated rock-forming minerals and the Fe3+ in redox-sensitive minerals like spinel or garnet. To date, accurate measurements of Fe3+ / ∑Fe in peridotites have been limited to those peridotites (e.g., harzburgites and lherzolites) for which an oxythermobarometer exists and where spinel (or garnet) crystals can be easily separated and measured by conventional 57Fe Mössbauer spectroscopy. Wehrlitic rocks have been generally formed by the interaction of a lherzolite with carbonatitic melts and, therefore, have recorded the passage of (metasomatic) fluids at mantle conditions. However, no oxythermobarometer exists to determine their equilibrium fO2. The aim of this study was to retrieve the fO2 of the mantle beneath Mt. Vulture volcano (Italy) through the study of a wehrlitic lapillus emitted during the last eruption (∼ 140 kyr ago) that contain olivines with multiple tiny spinel inclusions with sizes < 40 µm. To our knowledge, the Fe oxidation state of these inclusions has been never determined with the Mössbauer technique due to their small sizes. Here, we present measurements of the Fe3+ / ∑Fe using in situ synchrotron Mössbauer spectroscopy coupled with chemical and spectroscopic analysis of both host olivine and spinel inclusions. The results show Fe3+ / ∑Fe ratios of 0.03–0.05 for olivine and 0.40–0.45 for the included spinels, the latter of which appear higher than those reported in literature for mantle spinel harzburgites and lherzolites. Given the evidence of the mantle origin of the trapped spinels, we propose that the high fO2 (between 0.81 and 1.00 log above the fayalite–magnetite–quartz buffer; FMQ) likely results from the interaction between the pristine spinel lherzolite and a CO2-rich metasomatic agent prior to the spinel entrapment in olivines at mantle depths.

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13

Berry, Frank J., Lin Liwu, Du Hongzhang, Liang Dongbai, Tang Renyuan, Wang Chengyu, and Zhang Su. "An in situ Mössbauer spectroscopic investigation of titania-supported iron–ruthenium catalysts." Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases 83, no. 8 (1987): 2573. http://dx.doi.org/10.1039/f19878302573.

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14

BARTELS, O., K. BECKER, E. BUCHER, and W. SITTE. "In-situ Mössbauer spectroscopy and thermogravimetry of La0.2Sr0.8FeO3−Δ and La0.4Sr0.6FeO3−Δ." Solid State Ionics 177, no. 19-25 (October 15, 2006): 1677–80. http://dx.doi.org/10.1016/j.ssi.2006.03.042.

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15

Bødker, F., I. Chorkendorff, and S. Mørup. "Nitrogen chemisorption on α -Fe nanoparticles studied by in situ Mössbauer spectroscopy." Zeitschrift f�r Physik D Atoms, Molecules and Clusters 40, no. 1-4 (May 1, 1997): 152–54. http://dx.doi.org/10.1007/s004600050181.

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16

Peña Rodrı́guez, V. A., J. Flores Regalado, E. Baggio-Saitovitch, and E. C. Passamani. "Nanocrystallization process in Finemet-type alloys followed by in situ Mössbauer spectroscopy." Journal of Alloys and Compounds 379, no. 1-2 (October 2004): 23–27. http://dx.doi.org/10.1016/j.jallcom.2004.02.023.

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17

Lázár, K., A. M. Szeleczky, N. K. Mal, and A. V. Ramaswamy. "In situ 119Sn-Mössbauer spectroscopic study on MR, MEL, and MTW tin silicalites." Zeolites 19, no. 2-3 (August 1997): 123–27. http://dx.doi.org/10.1016/s0144-2449(97)00056-0.

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18

Mitov, I., S. Asenov, T. Tomov, and A. Andreev. "In situ Mössbauer spectroscopic investigation of iron-oxide based water-gas shift catalysts." Reaction Kinetics & Catalysis Letters 50, no. 1-2 (September 1993): 145–50. http://dx.doi.org/10.1007/bf02062201.

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19

David, B., N. Pizúrová, O. Schneeweiss, T. Hoder, V. Kudrle, and J. Janča. "Iron-Based Nanocomposite Synthesised by Microwave Plasma Decomposition of Iron Pentacarbonyl." Defect and Diffusion Forum 263 (March 2007): 147–52. http://dx.doi.org/10.4028/www.scientific.net/ddf.263.147.

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A nanocrystalline iron-based powder has been prepared by microwave plasma method: Fe(CO)5 vapor was introduced into an argon discharge at ~1 kPa. A microwave 2.45 GHz generator was operated at 430 W. The reaction took place inside a quartz tube passing through a microwave waveguide. The microwave discharge (without and with Fe(CO)5) was characterized by optical emission spectroscopy. The synthesized nanopowder was passivated in situ with air. The asprepared nanopowder was characterized by TEM, XRD, Raman and Mössbauer spectroscopies. The nanopowder included α-Fe, α-Fe2O3, and Fe3O4 phases. The core-shell nanoparticles were observed under TEM: α-Fe cores had shells formed of Fe3O4 or carbon. The mean crystallite size of α-Fe was 36 nm (Scherrer formula). The synthesized nanopowder exhibited ferromagnetic behavior.

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20

Aldon, L., C. M. Ionica, P. E. Lippens, D. Larcher, J. M. Tarascon, J. Olivier-Fourcade, and J. C. Jumas. "In situ 119Sn Mössbauer spectroscopy used to study lithium insertion in c-Mg2Sn." Hyperfine Interactions 167, no. 1-3 (November 14, 2006): 729–32. http://dx.doi.org/10.1007/s10751-006-9366-6.

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21

Korecki, J., and U. Gradmann. "In-situ conversion electron Mössbauer spectroscopy on Fe(110)-surfaces and thin films." Hyperfine Interactions 28, no. 1-4 (February 1986): 931–34. http://dx.doi.org/10.1007/bf02061597.

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22

Kirsch, Andrea, M. Mangir Murshed, Piotr Gaczynski, Klaus-Dieter Becker, and Thorsten M. Gesing. "Bi2Fe4O9: Structural changes from nano- to micro-crystalline state." Zeitschrift für Naturforschung B 71, no. 5 (May 1, 2016): 447–55. http://dx.doi.org/10.1515/znb-2015-0227.

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AbstractBi2Fe4O9 was synthesized using a polyol-mediated method. X-ray powder diffraction (XRPD) revealed that the as-synthesized sample is nano-crystalline. During heating, the X-ray amorphous powder transformed into a rhombohedral perovskite-type bismuth ferrate followed by a second transformation into mullite-type Bi2Fe4O9 at higher temperatures. This transformation was studied at in-situ conditions by temperature-dependent XRPD and 57Fe Mössbauer spectroscopy. The 57Fe Mössbauer spectra indicate the existence of two Fe3+ species at two different octahedrally coordinated sites leading to the conclusion that the as-synthesized powder of the polyol synthesis possesses a disordered (Bi1–xFex)FeO3 perovskite structure. Rietveld refinements have unambiguously supported this observation and this results suggest that one third of the Bi3+ sites are substituted by Fe3+ representing the initial chemical composition. This study has shown that as-synthesized nano-materials are not always similar to the respective micro-crystalline ones.

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23

de Resende, Valdirene G., Alain Peigney, Eddy De Grave, and Christophe Laurent. "In situ high-temperature Mössbauer spectroscopic study of carbon nanotube–Fe–Al2O3 nanocomposite powder." Thermochimica Acta 494, no. 1-2 (October 2009): 86–93. http://dx.doi.org/10.1016/j.tca.2009.04.024.

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24

Lázár, K., G. Lejeune, R. K. Ahedi, S. S. Shevade, and A. N. Kotasthane. "Interpreting the Oxidative Catalytic Activity in Iron-Substituted Ferrierites Using in Situ Mössbauer Spectroscopy." Journal of Physical Chemistry B 102, no. 25 (June 1998): 4865–70. http://dx.doi.org/10.1021/jp9734639.

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25

Hou, Kaipeng, Jonas Börgel, Henry Z. H. Jiang, Daniel J. SantaLucia, Hyunchul Kwon, Hao Zhuang, Khetpakorn Chakarawet, et al. "Reactive high-spin iron(IV)-oxo sites through dioxygen activation in a metal–organic framework." Science 382, no. 6670 (November 3, 2023): 547–53. http://dx.doi.org/10.1126/science.add7417.

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In nature, nonheme iron enzymes use dioxygen to generate high-spin iron(IV)=O species for a variety of oxygenation reactions. Although synthetic chemists have long sought to mimic this reactivity, the enzyme-like activation of O 2 to form high-spin iron(IV) = O species remains an unrealized goal. Here, we report a metal–organic framework featuring iron(II) sites with a local structure similar to that in α-ketoglutarate-dependent dioxygenases. The framework reacts with O 2 at low temperatures to form high-spin iron(IV) = O species that are characterized using in situ diffuse reflectance infrared Fourier transform, in situ and variable-field Mössbauer, Fe Kβ x-ray emission, and nuclear resonance vibrational spectroscopies. In the presence of O 2 , the framework is competent for catalytic oxygenation of cyclohexane and the stoichiometric conversion of ethane to ethanol.

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26

Luo, Fang, Aaron Roy, Moulay-Tahar Sougrati, Anastassiya Khan, David A. Cullen, Xingli Wang, Mathias Primbs, Andrea Zitolo, Frederic Jaouen, and Peter Strasser. "Operando x-Ray Absorption Spectroscopy Investigation of Secondary Metal Doping into Iron-Nitrogen-Carbon Catalysts for Oxygen Electroreduction." ECS Meeting Abstracts MA2023-02, no. 55 (December 22, 2023): 2676. http://dx.doi.org/10.1149/ma2023-02552676mtgabs.

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Oxygen reduction reaction (ORR) plays a key role in the development of fuel cell technology, and great efforts have been made to reduce the amount of platinum, required to speed up this sluggish reaction, or, even more desirable, to use efficient electrocatalysts based on earth-abundant metals. To date, numerous single-atom catalysts in the form of metal-doped carbon-nitrogen materials (MNC) have proved to be a promising alternative to ORR Pt-based materials. [1-3] In this study we employed advanced spectroscopic techniques, namely Mössbauer spectroscopy and operando X-ray absorption (XAS) spectroscopy, to understand the structural and electronic factors underlying an increase in the catalytic turn over frequency (TOF) of bimetallic FeSnNC and FeCoNC catalysts, relative to the parent FeNC materials. In particular, 57Fe Mössbauer spectroscopy identified a larger ratio of D1/D2 species in both bimetallic catalysts, supporting a larger ratio of Fe(III)-Nx/Fe(II)-Nx sites. The combination of extended X-ray absorption fine structure (EXAFS) modeling, and the analysis of operando X-ray absorption near-edge spectroscopy (XANES) spectra revealed a disordered carbon structure around FeNx active sites, and variations in the iron oxidation state that can be linked to the enhanced intrinsic catalytic reactivity (TOF). This talk is therefore intended to draw attention to the potential of the XAS technique, especially when applied to in-situ/operando studies in the field of electrocatalysis. References F. Luo, A. Roy, L. Silvioli, D.A. Cullen, A. Zitolo, M.T. Sougrati, I.C. Oguz, T. Mineva, D. Teschner, S. Wagner, J. Wen, F. Dionigi, U.I. Kramm, J. Rossmeisl, F. Jaouen and P. Strasser. P-block single-metal-site tin/nitrogen-doped carbon fuel cell cathode catalyst for oxygen reduction reaction. Nature Materials 2020, 19, 1215-1223 A. Zitolo, N. Ranjbar, T. Mineva, J. Li, Q. Jia, S. Stamatin, G.F. Harrington, S.M. Lyth, P. Krtil, S. Mukerjee, E. Fonda, F. Jaouen. Identification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction. Nature Communications 2017, 8(1), 957 A. Zitolo, V. Goellner, V. Armel, M. T. Sougrati, T. Mineva, L. Stievano, E. Fonda, F. Jaouen. Identification of catalytic sites for oxygen reduction in iron and nitrogen doped graphene materials. Nature Materials 2015, 14, 937-942

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27

Ni, Lingmei, Charlotte Gallenkamp, Markus Kübler, Pascal Theis, Eckhard Bill, Vera Krewald, and Ulrike I. Kramm. "Operando ⁵⁷ Fe Mössbauer Spectroscopy of Fe-N-C Catalysts during Oxygen Reduction Reaction." ECS Meeting Abstracts MA2022-02, no. 42 (October 9, 2022): 1596. http://dx.doi.org/10.1149/ma2022-02421596mtgabs.

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Proton exchange fuel cells (PEFCs) are a clean technology for efficient conversion of chemical into electrical energy and are specifically promising for the decarbonization of heavy duty vehicles [1]. Currently, the drawback of PEFCs is the high cost of Pt-based catalysts used for cathode and anode, which hinders their commercialization. [2] The rapid development of FeNCs holds promise for replacing Pt-based catalysts for the oxygen reduction reaction (ORR). The nature and characterization of the FeNC active sites is a challenging subject of research, and the exact structure of intrinsic active center for FeNC catalysts is still under debate. [3-6] 57Fe Mössbauer Spectroscopy is powerful in obtaining knowledge of iron sites, with respect to structural composition, electronic states as well as magnetic environment [3,7-9]. To solve the debate, 57Fe Mössbauer experiments were carried out under ex situ, in situ, or operando conditions to identify iron signatures and their changes induced by different conditions. On the basis of our in situ results of three differently prepared catalysts, two transitions between the oxygenated and deoxygenated state were found and assigned to sites involved in the direct and indirect ORR. [10-11] In order to gain an in-depth understanding of active sites operando conditions (thus during ORR) were performed for the FeNC catalyst that exhibited the strongest change during in situ testing. One iron signature (D4) gets exclusively formed under ORR conditions and its intensity scales with the ORR current. Together with density functional theory calculations the overall set of data enables us to make important conclusions on the ORR mechanism on FeNC catalysts. Literature: [1] M. K. Debe, Nature. 486, 2012, 43−51. [2] C. Sealy, Mater.Today.11, 2008, 65. [3] S. Wagner, H. Auerbach, et al. Angew. Chem. 131.31, 2019, 10596-10602. [4] A. Zitolo, V. Goellner, et al. Nat. Mater. 14.9, 2015, 937. [5] X.,Li, C. Cao, et al. Chem. 6, 2020, 3440–3454. [6] J. Li, M. T. Sougrati, et al. Nat. Catal. 4, 2021, 10–19. [7] U.I. Kramm, M. Lefèvre, et al. J. Am. Chem. Soc. 136, 2014, 978-985. [8] U.I. Kramm, J. Herranz, et al. Phys. Chem.Chem.Phys. 14, 2012,11673-11688. [9] U.I. Kramm, L. Ni, et al. Adv. Mater.31.31, 2019, 1805623. [10] L. Ni, C. Gallenkamp, et al. Adv. Energy Sustainability Res. 2, 2021, 2000064. [11] L. Ni, P. Theis,et al. Electrochim. Acta. 395, 2021, 139200.

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28

Buelens, Lukas C., Antoon Van Alboom, Hilde Poelman, Christophe Detavernier, Guy B. Marin, and Vladimir V. Galvita. "Fe2O3–MgAl2O4 for CO Production from CO2: Mössbauer Spectroscopy and in Situ X-ray Diffraction." ACS Sustainable Chemistry & Engineering 7, no. 10 (April 23, 2019): 9553–65. http://dx.doi.org/10.1021/acssuschemeng.9b01036.

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29

Bødker, F., and S. Mørup. "In situ cell for Mössbauer spectroscopy between 5 and 800 K in applied magnetic fields." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 108, no. 4 (March 1996): 413–16. http://dx.doi.org/10.1016/0168-583x(95)01154-4.

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30

Jumas, Jean-Claude, Manfred Womes, Ricardo Alcántara, Pedro Lavela, and José L. Tirado. "A 57Fe Mössbauer spectroscopy study of iron nanoparticles obtained in situ in conversion ferrite electrodes." Hyperfine Interactions 183, no. 1-3 (April 2008): 1–5. http://dx.doi.org/10.1007/s10751-008-9728-3.

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31

Benaichouba, B. "In-situ Mössbauer spectroscopic study of iron site evolution in iron and cobalt molybdates catalysts in propene oxidation reaction conditions." Applied Catalysis A: General 130, no. 1 (September 14, 1995): 31–45. http://dx.doi.org/10.1016/0926-860x(95)00112-3.

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32

Bouda, S., and K. P. Isaac. "Influence of soil redox conditions on oxidation of biotite." Clay Minerals 21, no. 2 (June 1986): 149–57. http://dx.doi.org/10.1180/claymin.1986.021.2.04.

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AbstractBiotites from three peaty gleyed podzol soil profiles on ranite bedrock were examined to investigate the oxidation of the octahedral Fe during weathering. Oxidation of these biotites as determined by Mössbauer spectroscopy shows a good correlation with the in situ measured soil Eh values of the sampled horizons. In every soil profile the highest Eh measured is in the A horizon and the lowest in the C horizon. Similarly, biotites from the A horizons are the most oxidized compared with those from the lower horizons. In most of the samples the oxidation is accompanied by loss of K+ from the lattice, as demonstrated by a moderate degree of vermiculitization.

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33

Ahmed, Ayman H. "Zeolite-encapsulated transition metal chelates: synthesis and characterization." Reviews in Inorganic Chemistry 34, no. 3 (October 1, 2014): 153–75. http://dx.doi.org/10.1515/revic-2013-0013.

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AbstractThis article reviews some important recent works on the synthesis and characterization of zeolite-encapsulated transition metal complexes containing different organic ligands. Distinct methodologies of preparation, including the in situ one-pot template (IOPT) and flexible ligand methods (FLM) are described. The mode of bonding, composition, overall geometry and surface characteristics have been inferred by various physicochemical characterization techniques. Chemical analysis, spectroscopic methods [Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS) and ultraviolet-visible (UV-Vis)], scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive spectroscopy analysis of X-ray (EDAX), magnetic measurements, N2-adsorption-desorption and thermogravimetric studies have been proven to be powerful techniques to specify these host-guest nanocomposite materials (HGNM). In some cases, Mössbauer, photoluminescence and cyclic voltammetric data are informative. Recent results dealing with the immobilization of complexes concerning aza, heterocyclic, Schiff base and hydrazone ligands are presented. A comprehensive survey of the investigated materials manifested the successful incorporation of the complexes into the zeolite matrix, without collapsing the crystalline structure of zeolite. Occasionally, some of the encapsulated complexes showed structural properties and chemical behavior which are different from those of the neat complex owing to the zeolite constraints.

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34

Berry, Frank J., Xu Changhai, and Simon Jobson. "An in situ Mössbauer spectroscopic investigation of the hydrogen pretreatment of titania-supported iron-iridium catalysts." Hyperfine Interactions 57, no. 1-4 (July 1990): 1759–63. http://dx.doi.org/10.1007/bf02405718.

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35

Biryukov, Yaroslav P., Almaz L. Zinnatullin, Rimma S. Bubnova, Farit G. Vagizov, Andrey P. Shablinskii, Stanislav K. Filatov, Vladimir V. Shilovskikh, and Igor V. Pekov. "Investigation of thermal behavior of mixed-valent iron borates vonsenite and hulsite containing [OM 4] n + and [OM 5] n + oxocentred polyhedra by in situ high-temperature Mössbauer spectroscopy, X-ray diffraction and thermal analysis." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 76, no. 4 (July 1, 2020): 543–53. http://dx.doi.org/10.1107/s2052520620006538.

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The investigation of elemental composition, crystal structure and thermal behavior of vonsenite and hulsite from the Titovskoe boron deposit in Russia is reported. The structures of the borates are described in terms of cation-centered and oxocentred polyhedra. There are different sequences of double chains and layers consisting of oxocentred [OM 4] n + tetrahedra and [OM 5] n + tetragonal pyramids forming a framework. Elemental composition was determined by energy-dispersive X-ray spectroscopy (EDX). Oxidation states and coordination sites of iron and tin in the oxoborates are determined using Mössbauer spectroscopy and compared with EDX and X-ray diffraction data (XRD). According to results obtained from high-temperature Mössbauer spectroscopy, the Fe2+ to Fe3+ oxidation in vonsenite and hulsite occurs at approximately 500 and 600 K, respectively. According to the high-temperature XRD data, this process is accompanied by an assumed deformation of crystal structures and subsequent solid-phase decomposition to hematite and warwickite. It is seen as a monotonic decrease of volume thermal expansion coefficients with an increase in temperature. A partial magnetic ordering in hulsite is observed for the first time with T c ≃ 383 K. Near this temperature, an unusual change of thermal expansion coefficients is revealed. Vonsenite starts to melt at 1571 K and hulsite melts at 1504 K. Eigenvalues of thermal expansion tensor are calculated for the oxoborates as well as anisotropy of the expansion is described in comparison with their crystal structures.

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36

Lázár, Károly. "Redistribution of iron ions in porous ferrisilicates during redox treatments." Pure and Applied Chemistry 89, no. 4 (April 1, 2017): 471–79. http://dx.doi.org/10.1515/pac-2016-1026.

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Abstract Relocation of iron ions in microporous Fe-FER, (Al+Fe)-FER, Fe-MFI (FER: ferrierite, MFI: silicalite) and in mesoporous Fe-MCM-41 ferrisilicate (MCM: Mobile Crystalline Material) samples was followed during redox treatments primarily by tool of the in situ Mössbauer spectroscopy. Coexistence of various Fe3+ and Fe2+ species is demonstrated. In microporous Fe-FER and Fe-MFI existence of combined μ-oxo iron dimers, Fe3+FW-O-Fe2+EFW can be proposed. The presence of these dimers can easily be correlated with catalytic effect shown in certain oxidation processes. Structural rearrangement can also be revealed in mesoporous Fe-MCM-41 which result in improvement of catalytic performance in CO oxidation.

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37

Yoshida, Y., S. Horie, K. Niira, K. Fukui, and K. Shirasawa. "In situ observation of iron atoms in multicrystalline silicon at 1273 and 300K by Mössbauer spectroscopy." Physica B: Condensed Matter 376-377 (April 2006): 227–30. http://dx.doi.org/10.1016/j.physb.2005.12.060.

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ALIFANTI, M., M. FLOREA, G. FILOTTI, V. KUNCSER, V. CORTESCORBERAN, and V. PARVULESCU. "In situ structural changes during toluene complete oxidation on supported EuCoO3 monitored with 151Eu Mössbauer spectroscopy." Catalysis Today 117, no. 1-3 (September 30, 2006): 329–36. http://dx.doi.org/10.1016/j.cattod.2006.05.036.

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39

Berry, F. J., and S. Jobson. "In situ characterisation of supported iron-iridium catalysts by iron-57 and iridium-193 Mössbauer spectroscopy." Hyperfine Interactions 46, no. 1-4 (March 1989): 557–65. http://dx.doi.org/10.1007/bf02398243.

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40

Zhang, Hui-Liang, Jian-yi Shen, and Xin Ge. "A study of in-situ Mössbauer spectroscopy on Fe−Mo oxides for selective oxidation of toluene." Hyperfine Interactions 69, no. 1-4 (April 1992): 859–62. http://dx.doi.org/10.1007/bf02401962.

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Somodi, Ferenc, Irina Borbáth, József L. Margitfalvi, Sándor Stichleutner, and Károly Lázár. "Study of Au/SnO x –Al2O3 catalysts used in CO oxidation by in situ Mössbauer spectroscopy." Hyperfine Interactions 192, no. 1-3 (April 1, 2009): 13–21. http://dx.doi.org/10.1007/s10751-009-9941-8.

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42

Chmielewski, Tomasz, Marcin Chmielewski, Anna Piątkowska, Agnieszka Grabias, Beata Skowrońska, and Piotr Siwek. "Phase Structure Evolution of the Fe-Al Arc-Sprayed Coating Stimulated by Annealing." Materials 14, no. 12 (June 10, 2021): 3210. http://dx.doi.org/10.3390/ma14123210.

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The article presents the results of research on the structural evolution of the composite Fe-Al-based coating deposited by arc spray with initial low participation of in situ intermetallic phases. The arc spraying process was carried out by simultaneously melting two different electrode wires, aluminum and low alloy steel (98.6 wt.% of Fe). The aim of the research was to reach protective coatings with a composite structure consisting of a significant participation of FexAly as intermetallic phases reinforcement. Initially, synthesis of intermetallic phases took place in situ during the spraying process. In the next step, participation of FexAly fraction was increased through the annealing process, with three temperature values, 700 °C, 800 °C, and 900 °C. Phase structure evolution of the Fe-Al arc-sprayed coating, stimulated by annealing, has been described by means of SEM images taken with a QBSD backscattered electron detector and by XRD and conversion electron Mössbauer spectroscopy (CEMS) investigations. Microhardness distribution of the investigated annealed coatings has been presented.

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Lázár, K., A. M.-Szeleczky, G. Vorbeck, R. Fricke, A. Vondrova, and J. Cejka. "In situ Mössbauer study of iron containing MFI ferrisilicates: Relations to catalytic properties." Journal of Radioanalytical and Nuclear Chemistry Articles 190, no. 2 (March 1995): 407–11. http://dx.doi.org/10.1007/bf02040019.

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44

Loiselle, Liane, Michael McCraig, M. Dyar, Richard Léveillé, Sean Shieh, and Gordon Southam. "A Spectral Comparison of Jarosites Using Techniques Relevant to the Robotic Exploration of Biosignatures on Mars." Life 8, no. 4 (December 6, 2018): 61. http://dx.doi.org/10.3390/life8040061.

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The acidic sulfate-rich waters of the Meridiani Planum region were potentially a habitable environment for iron-oxidizing bacteria on ancient Mars. If life existed in this ancient martian environment, jarosite minerals precipitating in these waters may record evidence of this biological activity. Since the Meridiani jarosite is thermodynamically stable at the martian surface, any biosignatures preserved in the jarosites may be readily available for analysis in the current surface sediments during the ongoing robotic exploration of Mars. However, thermal decomposition experiments indicate that organic compound detection of sediments containing jarosite may be challenging when using pyrolysis experiments; the instrument commonly used to assess organic matter in martian samples. So, here, we assess if the biogenicity of the Meridiani-type jarosites can be determined using complimentary spectroscopic techniques also utilized during the robotic exploration of Mars, including the upcoming ExoMars2020 rover mission. An abiotic jarosite, synthesized following established protocols, and a biological jarosite counterpart, derived from a microbial enrichment culture of Rio Tinto river sediments, were used to compare four spectroscopy techniques employed in the robotic exploration of Mars (Raman spectroscopy, mid-infrared (IR) spectroscopy, visible near-infrared reflectance (VNIR) spectroscopy and Mössbauer spectroscopy) to determine if the complimentary information obtained using these instruments can help elucidate the biological influence of Meridiani-type jarosites. Raman spectral differences might be due to the presence of unreacted reagents in the synthetic spectra and not biological contributions. Reflectance (IR/VNIR) spectra might exhibit minor organic absorption contributions, but are observed in both sample spectra, and do not represent a biosignature. Mössbauer spectra show minor differences in fit parameters that are related to crystal morphology and are unrelated to the biological (i.e., organic) component of the system. Results of this study suggest that the identification of biosignatures in Meridiani-type jarosites using the in situ robotic exploration on Mars may be possible but will be challenging. Our work provides additional insight into extraterrestrial biosignature detection and data interpretation for Mars exploration and indicates that sample return missions are likely required to unequivocally resolve the possible biogenicity of the Meridiani sediments or other jarosite-containing sediments.

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Aparicio, Claudia, Jan Filip, and Libor Machala. "From Prussian blue to iron carbides: high-temperature XRD monitoring of thermal transformation under inert gases." Powder Diffraction 32, S1 (May 8, 2017): S207—S212. http://dx.doi.org/10.1017/s0885715617000471.

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The thermal behavior and decomposition reaction of Prussian blue (PB) (Fe43+[Fe2+(CN)6]3·xH2O) was studied under inert atmosphere of argon by simultaneous thermogravimetry and differential scanning calorimetry, from room temperature up to 900 °C, with a heating rate of 5 K min−1. Parallel to the thermogravimetric measurements, the thermal process was monitored by in situ X-ray powder diffraction (XRD) technique under nitrogen atmosphere. The thermogravimetric data show six steps, corresponding to different stages of the decomposition reaction; comparable results are also obtained by in situ XRD. In addition, a set of PB samples heated up to selected temperatures (190, 300, 370, 540, 680, and 790 °C) were ex situ analyzed by powder XRD and Mössbauer spectroscopy. It is found that PB exhibits a negative thermal expansion prior to the water release from its crystalline lattice. Above 300 °C, the decomposition is based on the release of cyanogen gas from the PB structure. At 370 °C, a cubic iron cyanide compound is formed, while at higher temperatures several iron carbides were found. The subsequent thermal treatment of these carbides leads to the formation of metallic iron and graphite.

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Gallenkamp, Charlotte, Lingmei Ni, Vera Krewald, and Ulrike I. Kramm. "Oxygen Reduction Reaction on Fe-N-C Catalysts: A Computational Spectroscopy Study." ECS Meeting Abstracts MA2022-02, no. 42 (October 9, 2022): 1595. http://dx.doi.org/10.1149/ma2022-02421595mtgabs.

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The oxygen reduction reaction (ORR) plays an important role in proton exchange fuel cells (PEFCs). In PEFCs, ORR is the cathodic half-cell reaction complementary to the oxidation of the fuel, but since ORR has slow kinetics, it requires high amounts of catalyst. State-of-the-art ORR catalysts are based on the expensive metal platinum. Even though the amount of platinum needed for ORR in PEFCs has been reduced significantly over the last decade, it is still the major contributor to the cost of PEFCs, thus hindering the commercialization and accessibility of this technology.[1] Iron and nitrogen doped carbon (Fe-N-C) catalysts have gained a lot of research attention due to their high ORR activity, which makes them potential substitutes for platinum-based catalysts. In Fe-N-C catalysts, iron is thought to be atomically dispersed as pseudo-molecular active centres with four- or fivefold nitrogen coordination spheres which are embedded in graphene layers. Since Fe-N-C catalysts are typically prepared via pyrolysis, they have a highly amorphous structure and can contain multiple iron phases, which makes them difficult to characterize structurally and spectroscopically. Consequently, there is still a scientific debate on the exact nature of the active site, in terms of iron spin and oxidation states and its precise coordination environment.[2-4] Fe-57 Mössbauer spectroscopy can provide direct insights on iron spin and oxidation states and is used successfully to characterise the amorphous Fe-N-C catalysts. Until recently, the interpretation of Mössbauer spectra was limited to comparisons with small reference complexes which lack the extended π-systems of Fe-N-C catalysts.[2] Since synthesis of such extended π-systems as references is difficult, we have developed a library of computational models that encompasses different structural motifs and electronic structures. With increasing use of in situ and operando experiments on Fe-N-C catalysts, the interest in computational models for the interpretation of experimental Mössbauer spectra has grown.[4-6] In this contribution, we present our density functional theory results for different molecular Fe-N-C models with extended π-systems and discuss their electronic structures and spectroscopic properties. [1] L. Osmieri, et al. Current Opinion in Electrochemistry 2021, 25, 100627. [2] U. I. Kramm, et al. Advanced Materials 2019, 31, 1805623. [3] S. Wagner, et al. Angewandte Chemie International Edition 2019, 58, 10486. [4] L. Ni, C. Gallenkamp, et al. Advanced Energy & Sustainability Research 2021, 2, 2000064. [5] J. Li, et al. Nature Catalysis, 2021, 4, 10. [6] X. Liu, et al. Chem 2020, 6, 3440.

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Ivanova, Tatiana K., Irina P. Kremenetskaya, Andrey I. Novikov, Valentin G. Semenov, Anatoly G. Nikolaev, and Marina V. Slukovskaya. "In Situ Control of Thermal Activation Conditions by Color for Serpentines with a High Iron Content." Materials 14, no. 21 (November 8, 2021): 6731. http://dx.doi.org/10.3390/ma14216731.

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Serpentine heat treatment at temperatures of 650–750 °C yields magnesium–silicate reagent with high chemical activity. Precise and express control of roasting conditions in laboratory kilns and industrial aggregates is needed to derive thermally activated serpentines on a large scale. Color change in serpentines with a high iron content during roasting might be used to indicate the changes in chemical activity in the technological process. This study gives a scientific basis for the express control of roasting of such serpentines by comparing the colors of the obtained material and the reference sample. Serpentines with different chemical activity were studied by X-ray diffraction, Mössbauer spectroscopy, and optical spectroscopy. The color parameters were determined using RGB (red, green, blue), CIELAB (International Commission on Illumination 1976 L*a*b), and HSB (hue, brightness, saturation) color models. The color of heat-treated samples was found to be affected by changes in the crystallochemical characteristics of iron included in the structure of the serpentine minerals. The color characteristics given by the CIELAB model were in good coherence with the acid-neutralizing ability and optical spectra of heat-treated serpentines. Thus, in contrast to the long-term analysis by these methods, the control by color palette provides an express assessment of the quality of the resulting product.

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Guerlou‐Demourgues, L., L. Fournès, and C. Delmas. "In Situ 57Fe Mössbauer Spectroscopy Study of the Electrochemical Behavior of an Iron‐Substituted Nickel Hydroxide Electrode." Journal of The Electrochemical Society 143, no. 10 (October 1, 1996): 3083–88. http://dx.doi.org/10.1149/1.1837168.

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49

Berry, Frank J., Du Hongzhang, Simon Jobson, Liang Dongbai, and Lin Liwu. "Oxidation of iron in titania-supported iron–ruthenium under reducing conditions: in situ evidence from57Fe Mössbauer spectroscopy." J. Chem. Soc., Chem. Commun., no. 3 (1987): 186–88. http://dx.doi.org/10.1039/c39870000186.

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50

Bødker, Franz, Steen Mørup, and J. W. Niemantsverdriet. "In situ Mössbauer spectroscopy of carbon-supported iron catalysts at cryogenic temperatures and in external magnetic fields." Catalysis Letters 13, no. 3 (September 1992): 195–202. http://dx.doi.org/10.1007/bf00770991.

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