Tomographic x-ray absorption spectroscopy

Schroer, Christian G.; Kuhlmann, Marion; Günzler, Til Florian; Lengeler, B.; Richwin, M.; Griesebock, B.; Lützenkirchen‐Hecht, Dirk; Frahm, R.; Ziegler, Eric; Mashayekhi, Ali N.; Haeffner, D. R.; Grunwaldt, Jan‐Dierk; Baiker, Alfons

doi:10.1117/12.559706

Cited by 10 publications

(15 citation statements)

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“…Recent progress has led to the development and application of the non‐invasive techniques mentioned above (X‐ray tomography, micro‐X‐ray fluorescence tomography) and MRI,15 tomographic energy‐dispersive diffraction imaging16 and XAS tomography 3c. 5, 17 In addition, microspectroscopic techniques have been applied by Weckhuysen and co‐workers3b to study different preparation steps, including non‐dried and non‐calcined samples. Despite the use of techniques such as Raman, UV/Vis and IR microspectroscopy and scanning electron microscopy (SEM), which usually require cleavage of the catalyst bodies along their z ‐axis, a much better understanding of the impregnation process could be achieved.…”

Section: Imaging Catalytic Reactors and Catalyst Bodies: Catalyst mentioning

confidence: 99%

“…It should also be noted that the spectral resolution of 50–100 μm currently offered by UV/Vis, Raman and MRI should be improved. One possibility is to use full‐field or scanning X‐ray microscopy, which provides a spectral resolution of a few μm or less3c,e, 5, 17, 24 and is complementary to tomographic energy‐dispersive diffraction imaging, which requires the presence of crystalline particles. Very recent studies in this direction have been performed by using computed tomography (CT) on Ni/Al 2 O 3 catalysts for CO methanation by synchrotron μ‐XRD‐CT and μ‐absorption‐CT 25.…”

Section: Imaging Catalytic Reactors and Catalyst Bodies: Catalyst mentioning

confidence: 99%

“…Here, focused ion beam sectioning techniques in the scanning electron microscope are becoming increasingly powerful 76. Moreover, scanning X‐ray microscopy using a nanofocused beam, which is similar to the scanning X‐ray microscopy techniques described in section 2, can be used to provide X‐ray absorption spectroscopic,17 fluorescence77 and scattering (wide‐ and small‐ angle X‐ray scattering, WAXS78 and SAXS79) contrast. In this way, local structural information can be obtained on the meso‐scale.…”

Section: Towards Spatial Information On the Meso‐ To The Micro‐scalementioning

confidence: 99%

“…For scanning microscopy with absorption spectroscopic contrast, X‐ray mirrors are best suited, as they are achromatic and the focus is (nearly) independent of the X‐ray energy. Absorption spectroscopic microscopy is well established in the soft X‐ray range using Fresnel zone plates and has more recently also been pursued in the hard X‐ray range 17. This technique still requires improvement in spatial resolution, which will be possible for harder X‐rays in third generation synchrotrons that have higher brilliance, e.g., PETRA III in Hamburg 83…”

Section: Towards Spatial Information On the Meso‐ To The Micro‐scalementioning

confidence: 99%

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Imaging Catalysts at Work: A Hierarchical Approach from the Macro‐ to the Meso‐ and Nano‐scale

2012

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This review highlights the importance of developing multi‐scale characterisation techniques for analysing operating catalysts in their working environment. We emphasise that a hierarchy of in situ techniques that provides macro‐, meso‐ and nano‐scale information is required to elucidate and optimise catalyst performance fully. This combined methodology should ideally embrace spatially resolved and spatio‐temporal monitoring of a) the structure, catalytic activity, temperature and heat/mass transfer pattern in axial and radial directions in real reactors, b) the structure and temperature/heat/mass transport gradients in shaped catalysts and catalyst grains and c) meso‐ and nano‐scale information about particles and clusters, whose physical and electronic properties are linked directly to the micro‐kinetic behaviour of the catalysts. Techniques such as X‐ray diffraction (XRD), infrared (IR), Raman, X‐ray photoelectron spectroscopy (XPS), UV/Vis, and X‐ray absorption spectroscopy (XAS), which have mainly provided global atomic scale information, are being developed to provide the same information on a more local scale, often with sub‐second time resolution. X‐ray microscopy, both in the soft and more recently in the hard X‐ray regime, allows two‐ and three‐dimensional information to be collected down to 10 nm spatial resolution in a gas atmosphere or liquid, although this improvement is at the expense of temporal resolution. Electron microscopy, which provides excellent local atomic scale structural and spectroscopic information, is being developed towards tomographic imaging and realistic conditions, allowing gaps to be bridged in pressure, reaction conditions and length scales, up to the meso‐ and macro‐scale. In addition, new techniques such as single molecule fluorescence spectroscopy and non‐linear spectroscopic techniques are emerging. In this review, we discuss prospects for the development and combined application of both existing and new techniques for in situ catalyst characterisation.

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Section: Imaging Catalytic Reactors and Catalyst Bodies: Catalyst mentioning

confidence: 99%

Section: Imaging Catalytic Reactors and Catalyst Bodies: Catalyst mentioning

confidence: 99%

Section: Towards Spatial Information On the Meso‐ To The Micro‐scalementioning

confidence: 99%

Section: Towards Spatial Information On the Meso‐ To The Micro‐scalementioning

confidence: 99%

See 2 more Smart Citations

Imaging Catalysts at Work: A Hierarchical Approach from the Macro‐ to the Meso‐ and Nano‐scale

2012

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“…A variety of hard x-ray microtomography techniques has been developed in the past few years, such as fluorescence microtomography 1 and tomographic x-ray absorption spectroscopy. 2 The main advantage of these techniques is that one can obtain elemental and chemical information from inside a specimen.…”

Section: N Stribeck and A Almendarez-camarillomentioning

confidence: 99%