Quantitative use of electron energy-loss spectroscopy Mo-M2,3 edges for the study of molybdenum oxides

Lajaunie, Luc; Boucher, Florent; Dessapt, Rémi; Moreau, Philippe

doi:10.1016/j.ultramic.2014.11.002

Cited by 65 publications

(89 citation statements)

References 62 publications

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“…EELS elemental quantification of the outer layer yields an S/Cr ratio nearly equal to 1, although it is important to keep in mind that precise and accurate EELS quantification requires comparison with reference materials. 23 It is noteworthy that this CrS outer layer was observed in nearly all the nanotubes investigated by EELS. The outer layer was also imaged on C s -HRTEM micrographs ( Figure S4 in the Supporting Information), which highlights its crystalline nature.…”

Section: Methodsmentioning

confidence: 90%

Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS₂

et al. 2015

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Various nanotubes from ternary misfit compounds have been reported in recent years. In the present work, the detailed atomic structure and chemical configuration of misfit-layered nanotubes based on the TbS-CrS 2 are reported. These analyses have been developed via different transmission electron microscopy techniques, including highresolution scanning transmission electron microscopy, electron diffraction, and electron energy loss spectroscopy. These structural analyses show that two different kinds of nanotubes can be produced: a "regular" nanotube and a "wavy" one. Both kinds of nanotubes show the alternating arrangements of the TbS and CrS 2 subsystems; however, the wavy ones present a nearly periodically deficiency in terbium. In addition to the structural investigation, the chemical analyses have proved that the outer layer of both kinds of nanotubes is composed of the elements Cr and S. All these findings helped to understand the growth mechanism during the sulfurization reaction taking place in the synthesis process.

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Section: Methodsmentioning

confidence: 90%

Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS₂

et al. 2015

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“…The backgrounds of these spectra were substracted using a power law and were normalized to the total carbon at 320 eV. To calculate the C/N ratios, we used the following equation from Lajaunie et al (2015):…”

Section: Stem-eelsmentioning

confidence: 99%

Isotope record of mineralogical changes in a spectrum of aqueously altered CM chondrites

Kooten

Nagashima

Kasama

et al. 2018

Geochimica et Cosmochimica Acta

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The recent fall of the relatively unaltered CM chondrite Maribo provides a unique opportunity to study the early stages of aqueous alteration on the CM chondrite parent body. We show using transmission electron microscopy of a matrix FIBsection from Maribo that this meteorite mainly appears to consist of tochilinite-cronstedtite intergrowths (TCIs), but also contains regions of amorphous or nanocrystalline silicates, anhydrous silicates and FeNi metal aggregates with thin iron oxide rims, suggesting that it experienced aqueous alteration to a relatively small degree. A comparison of Maribo with increasingly altered CM chondrites such as Jbilet Winselwan and Bells shows that during progressive aqueous alteration (1) the TCIs are replaced by coarser sulfides and increasingly Mg-rich serpentine, and (2) the abundance of 15 N-rich hotspots increases, whereas the magnitude of their 15 N enrichment decreases. We observe that the overall N isotope variability related to aqueous alteration is an order of magnitude lower than the variability observed between different chondrite groups. We suggest these high order differences are the result of heterogeneous accretion of insoluble or soluble organic carriers of 15 N to the different chondrite parent bodies. D/H ratios of matrices from Maribo, Jbilet Winselwan and Bells increase with progressive aqueous alteration, a trend that is opposite to expectations of mixing between D-poor water and D-rich organic matter. We argue that this behaviour cannot be related to Fe oxidation or serpentinization reactions and subsequent loss of D-poor H 2 gas. We offer an alternative hypothesis and suggest that CM chondrites experienced two-stage aqueous alteration. During the first stage occurring at relatively low temperature, mixing of increasing amounts of D-poor water with D-rich organic matter results in a decrease of D/H ratio with increasing degree of alteration. During the second stage of alteration occurring at relatively high temperature (T < 300°C), decomposition of TCIs in CMs of petrologic type <2.7 releases gaseous D-poor water that results in increase of the D/H ratio of the CM matrices. Finally, we report on changes in the organic structure of Maribo, Jbilet Winselwan and Bells using Carbon-K and Nitrogen-K edge electron energy loss spectroscopy. The organic matter initially has higher aromatic/aliphatic ratios (e.g., Maribo) and lower abundances of ketone and carboxyl functional groups, which we suggest are the result of chemical degradation of double bonded carbon from oxidation during hydrothermal

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“…Thus, in addition of this spectroscopic technique, electron energy-loss spectroscopy (EELS) performed in a (Scanning) transmission electron microscope ((S)TEM) is a complementary technique, which gives access to a wealth of structural, chemical and physical information with nanometer to sub-angstrom spatial resolution [41][42][43][44][45][46][47]. Analysis of core-loss EELS spectra yields qualitative and quantitative information on the elemental composition and on the local chemical environment (bonding configuration, valence state…) [48][49][50][51][52]. The fine structures of the C-K edge can be used to distinguish the different carbon allotropes [41,45,48,[53][54][55].…”

Section: Introductionmentioning

confidence: 99%

Advanced spectroscopic analyses on a:C-H materials: Revisiting the EELS characterization and its coupling with multi-wavelength Raman spectroscopy

Lajaunie

Pardanaud

Martin

et al. 2017

Carbon

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Hydrogenated amorphous carbon thin films (a:C-H) are very promising materials for numerous applications. The growing of relevance of a:C-H is mainly due to the long-term stability of their outstanding properties. For improving their performances, a full understanding of their local chemistry is highly required. Fifteen years ago, electron energy-loss spectroscopy (EELS), developed in a transmission electron microscope (TEM), was the technique of choice to extract such kind of quantitative information on these materials. Other optical techniques, as Raman spectroscopy, are now clearly favored by the scientific community. However, they still lack of 2 the spatial resolution offered by TEM-EELS. In addition, nowadays, the complexity of the physics phenomena behind EELS is better known. Here, a:C-H thin films have been isothermally annealed and the evolution of their physical and chemical parameters have been monitored at the local and macroscopic scales. In particular, chemical in-depth inhomogeneities and their origins are highlighted. Furthermore, a novel procedure to extract properly and reliably quantitative chemical information from EEL spectra is presented. Finally, the pertinence of empirical models used by the Raman community is discussed. These works demonstrate the pertinence of the combination of local and macroscopic analyses for a proper study of such complex materials.

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Quantitative use of electron energy-loss spectroscopy Mo-M2,3 edges for the study of molybdenum oxides

Cited by 65 publications

References 62 publications

Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS₂

Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS₂

Isotope record of mineralogical changes in a spectrum of aqueously altered CM chondrites

Advanced spectroscopic analyses on a:C-H materials: Revisiting the EELS characterization and its coupling with multi-wavelength Raman spectroscopy

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Quantitative use of electron energy-loss spectroscopy Mo-M2,3 edges for the study of molybdenum oxides

Cited by 65 publications

References 62 publications

Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS2

Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS2

Isotope record of mineralogical changes in a spectrum of aqueously altered CM chondrites

Advanced spectroscopic analyses on a:C-H materials: Revisiting the EELS characterization and its coupling with multi-wavelength Raman spectroscopy

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Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS₂

Atomic Structural Studies on Thin Single-Crystalline Misfit-Layered Nanotubes of TbS-CrS₂