Advantages of soft X-ray absorption over TEM-EELS for solid carbon studies––a comparative study on diesel soot with EELS and NEXAFS

Braun, Artur; Huggins, Frank E.; Shah, Naresh; Chen, Yuanzhi; Wirick, S.; Mun, Simon; Jacobsen, Chris; Huffman, G.P.

doi:10.1016/j.carbon.2004.08.029

Cited by 145 publications

(133 citation statements)

References 19 publications

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“…Characteristic resonances in the spectra allow for direct molecular speciation of the graphite-like solid core, aromatic components, and surface functional groups (between ∼286 and 290 eV), depending on the origin of the soot. Such detailed analyses can only be attained with NEXAFS (7). Combining NEXAFS spectroscopy and zone plate imaging, scanning transmission X-ray microscopes (STXMs) provide both high chemical sensitivity and a spatial resolution less than 40 nm which allows gaining more detailed information on the variation in structures of single soot particles depending on the combustion source.…”

Section: Introductionmentioning

confidence: 99%

On Source Identification and Alteration of Single Diesel and Wood Smoke Soot Particles in the Atmosphere; An X-Ray Microspectroscopy Study

Vernooij

Mohr

Tzvetkov

et al. 2009

Environ. Sci. Technol.

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Diesel and wood combustion are major sources of carbonaceous particles in the atmosphere. It is very hard to distinguish between the two sources by looking at soot particle morphology, but clear differences in the chemical structure of single particles are revealed by C(1s) NEXAFS (near edge X-ray absorption fine structure) microspectroscopy. Soot from diesel combustion has a dominant spectral signature at ∼285 eV from aromatic π-bonds, whereas soot from wood combustion has the strongest signature at ∼287 eV from phenolic carbon bonds. To investigate if it is possible to use these signatures for source apportionment purposes, we collected atmospheric samples with either diesel or wood combustion as a dominant particle source. No spectra obtained from the atmospheric particles completely matched the emission spectra. Especially particles from the wood dominated location underwent large modifications; the phenolic spectral signature at ∼287 eV is greatly suppressed and surpassed by the peak attributed to the aromatic carbon groups at ∼285 eV. Comparison with spectra from diesel soot samples experimentally aged with ozone show that very fast modification of the carbon structure of soot particles occurs as soon as they enter the atmosphere. Source attribution of single soot particles with microspectroscopy is thus hardly possible, but NEXAFS remains a powerful tool to study aging effects.

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Section: Introductionmentioning

confidence: 99%

On Source Identification and Alteration of Single Diesel and Wood Smoke Soot Particles in the Atmosphere; An X-Ray Microspectroscopy Study

Vernooij

Mohr

Tzvetkov

et al. 2009

Environ. Sci. Technol.

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“…Conjugated synchrotron STXM and C 1s-NEXAFS was also widely used as a direct solid-state technique to resolve nanostructures of polymers (Smith et al, 2001) and to fingerprint C in biological materials (Hitchcock et al, 2005;Lerotic et al, 2004), where radiation exposure is controlled to avoid damage to the susceptible C¼O bond (Braun et al, 2005;Rightor et al, 1997). High concentrations of C in uniform polymer-layered samples (Ade and Urquhart, 2002) and black C permit NEXAFS data filtering, thereby improving the signal-to-noise ratio of the images allowing to effectively fingerprint the various C functionalities present in these samples.…”

Section: Resolving Key Questions In Soil Biogeochemistrymentioning

confidence: 99%

Organic Carbon Chemistry in Soils Observed by Synchrotron-Based Spectroscopy

Lehmann

Solomon

2010

Developments in Soil Science

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“…The spectra obtained by STEM-EELS are similar to those obtained using Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy; however, the spatial resolution of STEM-EELS is better than the spatial resolution of X-ray absorption spectroscopy, which is approximately 50 nm using a Scanning Transmission X-ray Microscope (STXM) (Benzerara et al 2005;Braun et al 2005;Hitchcock et al 2005). In contrast, the energy resolution of STXM-NEXAFS surpasses that of STEM-EELS (Rightor et al 1997;Braun et al 2005). Finally, site-specifi c electron diffraction patterns can be collected at the nanoscale using Selected-Area Electron Diffraction (SAED), microdiffraction, and/or Convergent Beam Electron Diffraction (CBED) techniques.…”

Section: Introductionmentioning

confidence: 74%

“…Similar to EDS, EELS data provide information about the chemical composition of the material, but the spectra can also be used to determine the chemical bonding environment and valence for chemical components of the material (Egerton 1996). The spectra obtained by STEM-EELS are similar to those obtained using Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy; however, the spatial resolution of STEM-EELS is better than the spatial resolution of X-ray absorption spectroscopy, which is approximately 50 nm using a Scanning Transmission X-ray Microscope (STXM) (Benzerara et al 2005;Braun et al 2005;Hitchcock et al 2005). In contrast, the energy resolution of STXM-NEXAFS surpasses that of STEM-EELS (Rightor et al 1997;Braun et al 2005).…”

Section: Introductionmentioning

confidence: 91%

Geoscience at the nanometre scale: review of analytical transmission electron microscopy applications

Petrunic

Cavé

et al. 2006

atgeol

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This paper describes applications of analytical Transmission Electron Microscopy (TEM) in the geosciences. The topics include: 1) sulphide-mineral oxidation; 2) trace-metal attenuation by secondary Mn oxides; 3) silicate weathering; 4) transition-metal valence in minerals; and 5) secondary Hg minerals in stream sediments. The main advantage of the analytical TEM is the ability to obtain images, chemical information, and electron diffraction patterns at the nanometre scale. With such high spatial resolution, it is possible to observe physical and chemical features in samples that cannot be resolved with most other techniques. This information can lead to signifi cant improvement in our understanding of the system under investigation. Sample preparation techniques that are used in each study are also described in this paper. The preparation of samples for TEM analysis can be challenging because of the heterogeneity commonly encountered in geological materials, the fragility of some geological samples (e.g., low-temperature minerals), and the need to maintain spatial relationships present in the samples. The sample preparation techniques presented are specifi c to the needs of the study and the appropriateness of these methods is demonstrated by the high quality analytical TEM data that are obtained. RÉSUMÉCet exposé décrit des applications de la microscopie électronique à transmission analytique dans les sciences de la terre. Les aspects étudiés comprennent : 1) l'oxydation des minéraux sulfurés; 2) l'atténuation des métaux-traces par des oxydes de Mn secondaires; 3) la silicatisation météorique; 4) la valence des métaux de transition dans les minéraux; et 5) les minéraux de Hg secondaires dans les sédiments fl uviatiles. Le principal avantage qu'offre la MET analytique est la possibilité d'obtenir des images, des données chimiques et des fi gures de diffraction des électrons à l'échelle nanométrique. Une résolution spatiale aussi élevée permet l'observation dans les échantillons de propriétés physiques et chimiques impossibles à éclaircir au moyen de la majorité des autres techniques. De tels renseignements peuvent mener à une amélioration marquée de notre compréhension du système à l'étude. Cet exposé décrit en plus les techniques de préparation des échantillons utilisées lors de chaque étude. La préparation des échantillons à une analyse MET peut s'avérer compliquée en raison de l'hétérogénéité que présentent communément les matières géologiques, de la fragilité de certains échantillons géologiques (p. ex. minéraux à basse température) et de la néces-sité de maintenir les liens spatiaux présents dans les échantillons. Les techniques de préparation des échantillons présentées sont propres aux besoins de l'étude; les données de haute qualité obtenues des analyses MET témoignent de la pertinence de ces méthodes.

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Advantages of soft X-ray absorption over TEM-EELS for solid carbon studies––a comparative study on diesel soot with EELS and NEXAFS

Cited by 145 publications

References 19 publications

On Source Identification and Alteration of Single Diesel and Wood Smoke Soot Particles in the Atmosphere; An X-Ray Microspectroscopy Study

On Source Identification and Alteration of Single Diesel and Wood Smoke Soot Particles in the Atmosphere; An X-Ray Microspectroscopy Study

Organic Carbon Chemistry in Soils Observed by Synchrotron-Based Spectroscopy

Geoscience at the nanometre scale: review of analytical transmission electron microscopy applications

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