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Seminários


Próximo Seminário: 
14/11/2019
Palestrante: Dr. Dario Ferreira Sanchez - currículo lattes
Título: Hyperspectral Chemical Imaging in Space and Time using Synchrotron Light
Resumo: Commonly in technological functional/engineered materials as well as in
nearly all inorganic or biological materials in nature, pronounced
physical and chemical heterogeneities are observed at various length and
time scales. These complex hierarchical structures potentially dictate the
macroscopic physical properties and chemical reaction pathways in space
and time. Consequently, being able to unveil physicochemical properties at
relevant spatial and temporal length scales is fundamental for the
understanding of properties, function, and reactivity of materials.

Imaging is frequently limited to morphological analysis; however, very
often imaging disclosing physicochemical properties turns out to be
essential. Therefore, the need for “chemical microscopes” is growing
rapidly. In that regard, synchrotron-based techniques have been applied to
provide, in a nondestructive manner, high-resolution imaging of chemical
speciation for various complexes and heterogeneous systems. The use of
several X-ray techniques providing chemical contrast such as X-ray
fluorescence (XRF), X-ray absorption spectroscopy (XAS) or X-ray
diffraction (XRD) in a simultaneous and/or combined manner allow the
recording of multimodal and multidimensional/hyperspectral datasets. Among
their advantages, it can be mentioned:

(i) the potential to perform in-situ experiments;

(ii) resolution that can be achieved down to the tens of nanometers;

(iii) in addition to 2D scanning analysis studies (‘chemical images’)
based on spectro-microscopy and XRD-imaging also, due to the considerable
penetration power of (hard) x-rays, investigations in 3D (‘chemical
tomography’) are also feasible, which provides means to derive local
chemical information from within intact, undisturbed objects or materials;

(iv) ability to get depth resolved crystalline contrast by analyzing the
XRD and chemical–elemental contrast by analyzing the XRF;

(v) element-specific chemical sensitivity by tuning the X-ray energies
around element-specific absorption resonances.
In this presentation, recent progress and achievements in the field of
2D/3D chemical imaging and speciation analysis using various synchrotron
radiation x-ray microprobe techniques, as well as on full-field ones will
be presented. Examples from a wide range of scientific disciplines,
including materials science, environmental science, or biology, will be
presented, which will include applied research in to health and
environmental sciences [1,2], energy [3–5] and catalysis [6–8]. Future
prospects will be addressed and arising new research opportunities will be
outlined.

References:
[1] Kapishnikov, S. et al. Unraveling heme detoxification in the malaria
parasite by in situ correlative X-ray fluorescence microscopy and soft
X-ray tomography. Sci. Rep. 7, 1–12 (2017).
[2] Sanchez, D. F. et al. 2D/3D Microanalysis by Energy Dispersive X-ray
Absorption Spectroscopy Tomography. Sci. Rep. 7, 1– 13 (2017).
[3] Laurencin, J. et al. Degradation mechanism of La 0.6 Sr 0.4 Co 0.2 Fe
0.8 O 3-δ /Gd 0.1 Ce 0.9 O 2-δ composite electrode operated
under solid oxide electrolysis and fuel cell conditions. Electrochim. Acta
241, 459–476 (2017).
[4] Sanchez, D. F., Grolimund, D., Hubert, M., Bleuet, P. & Laurencin, J.
A 2D and 3D X-ray μ-diffraction and μ-fluorescence study of a
mixed ionic electronic conductor. Int. J. Hydrogen Energy 1–9 (2016).
doi:10.1016/j.ijhydene.2016.11.094
[5] Tsai, E. H. R. et al. Correlated X-Ray 3D Ptychography and Diffraction
Microscopy Visualize Links between Morphology and Crystal Structure of
Lithium-Rich Cathode Materials. iScience 11, 356–365 (2019).
[6] Ihli, J. et al. Localization and Speciation of Iron Impurities within
a Fluid Catalytic Cracking Catalyst. Angew. Chemie - Int. Ed. 56, (2017).
[7] Ihli, J. et al. A three-dimensional view of structural changes caused
by deactivation of fluid catalytic cracking catalysts. Nat. Commun. 8,
(2017).
[8] Ranocchiari, M., Ferreira Sanchez, D. & Van Bokhoven, J. A. X-ray
chemical nano-imaging to monitor chemical and structural changes in
metal-organic framework HKUST-1. Prep.
Horário: 15h30min
Local: Auditório do PPGF (sala 108)

Próximos seminários:

21/11/2019
Palestrante: Prof. Lucas Mauricio Sigaud, IF/UFF - currículo lattes

28/11/2019
Palestrante: Jean-Marie George, Unité Mixte de Physique, CNRS/Thales - currículo

05/12/2019
Palestrante: Dr. Fernando Pablo Devecchi, Departamento de Física, UFPR - currículo lattes

12/12/2019
Palestrante: Dr. Ana Cristina Sprotte Costa, Departamento de Física, UFPR - currículo lattes