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Breakthroughs in hard X-ray diffraction: towards a multiscale science approach in heterogeneous catalysis.

Ristanović Z, Weckhuysen BM - Angew. Chem. Int. Ed. Engl. (2014)

View Article: PubMed Central - PubMed

Affiliation: Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht (The Netherlands).

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Ever since the first diffraction pattern was recorded by Max von Laue, X‐ray diffraction (XRD) has been developed into a widely used, powerful, and indispensable characterization method for structural analysis. 1 A real revolution in using X‐rays for diffraction analysis happened with the advent of synchrotron radiation... Nowadays, numerous synchrotron facilities around the world provide highly brilliant, focused X‐rays with tunable energies... The energies of hard X‐rays (typically 5–100 keV) provide deep penetration into matter, which enables studies under elevated temperatures and pressures... Another benefit of hard X‐rays is that beam damage is significantly reduced... These features of hard X‐rays provide researchers with the ideal method to study catalysts under working conditions at different length scales, that is, at the level of the active surface of a catalyst material, of a catalyst body placed in a reactor, and of the chemical reactor itself... By using a novel surface scattering geometry, Gustafson et al. 2 took advantage of high‐energy X‐rays (85 keV) by grazing incidence geometry... Surface scattering results in streaking of the Bragg reflections, a phenomenon that is due to the termination of the surface... Furthermore, scattered intensity and detector sensitivity drop with an increase in photon energy, whereas the time resolution of tomographic experiments is still a serious drawback for monitoring fast reaction processes... With the upgrades of the third‐generation synchrotrons, the performance of XRD has greatly improved over the past decade... These efforts should lead to even more significant improvements of the X‐ray beam brilliance and coherence, the speed and sensitivity of X‐ray detectors, and nano‐focusing optics... Considering also the potential of free electron lasers (FELs),5 one can only foresee a brilliant future for XRD in unravelling catalytic processes in detail and in bridging the molecular world with the macroscopic world.

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Three recent reports are highlighted to show the potential of a multiscale science approach for studying heterogeneous catalysts at work with advanced X‐ray diffraction methods. a) An atomic model of a Pd surface during CO oxidation.2 b) A single diffraction image representing all of the images recorded during a rotational scan. Individual CTRs and superlattice rods are visible.2 c) Pd/Al2O3 catalyst body showing the particle size distribution measured by PDF‐CT.3 d, e) Experimental and fitted PDF data for single pixels at the edge (d) and in the interior (e) of the particle.3 f) Schematic representation of a capillary reactor used for the MTO reaction, showing the crystallographic changes as a function of the catalyst bed height. The color scale (from blue to red) indicates an expansion of the crystallographic c axis with increasing time on stream.4 g) Scatter plot of a z‐scan of the MTO reaction in a large reactor, compared to a line plot from capillary reactor data. Images are adapted from Ref. 2–4.
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fig1: Three recent reports are highlighted to show the potential of a multiscale science approach for studying heterogeneous catalysts at work with advanced X‐ray diffraction methods. a) An atomic model of a Pd surface during CO oxidation.2 b) A single diffraction image representing all of the images recorded during a rotational scan. Individual CTRs and superlattice rods are visible.2 c) Pd/Al2O3 catalyst body showing the particle size distribution measured by PDF‐CT.3 d, e) Experimental and fitted PDF data for single pixels at the edge (d) and in the interior (e) of the particle.3 f) Schematic representation of a capillary reactor used for the MTO reaction, showing the crystallographic changes as a function of the catalyst bed height. The color scale (from blue to red) indicates an expansion of the crystallographic c axis with increasing time on stream.4 g) Scatter plot of a z‐scan of the MTO reaction in a large reactor, compared to a line plot from capillary reactor data. Images are adapted from Ref. 2–4.

Mentions: The scientific community has recently celebrated the centennial of X‐ray diffraction. Ever since the first diffraction pattern was recorded by Max von Laue, X‐ray diffraction (XRD) has been developed into a widely used, powerful, and indispensable characterization method for structural analysis.1 A real revolution in using X‐rays for diffraction analysis happened with the advent of synchrotron radiation. Nowadays, numerous synchrotron facilities around the world provide highly brilliant, focused X‐rays with tunable energies. The energies of hard X‐rays (typically 5–100 keV) provide deep penetration into matter, which enables studies under elevated temperatures and pressures. Another benefit of hard X‐rays is that beam damage is significantly reduced. These features of hard X‐rays provide researchers with the ideal method to study catalysts under working conditions at different length scales, that is, at the level of the active surface of a catalyst material, of a catalyst body placed in a reactor, and of the chemical reactor itself. In this manner, it is possible to span a wide range of length scales, enabling a full multiscale science analysis of the dynamics of structurally complex catalytic materials. This highlight discusses the potential of modern hard X‐ray techniques to provide such a multiscale science approach for investigating heterogeneous catalysts at work by presenting some recent experiments that were the first of their kind (Figure 1).


Breakthroughs in hard X-ray diffraction: towards a multiscale science approach in heterogeneous catalysis.

Ristanović Z, Weckhuysen BM - Angew. Chem. Int. Ed. Engl. (2014)

Three recent reports are highlighted to show the potential of a multiscale science approach for studying heterogeneous catalysts at work with advanced X‐ray diffraction methods. a) An atomic model of a Pd surface during CO oxidation.2 b) A single diffraction image representing all of the images recorded during a rotational scan. Individual CTRs and superlattice rods are visible.2 c) Pd/Al2O3 catalyst body showing the particle size distribution measured by PDF‐CT.3 d, e) Experimental and fitted PDF data for single pixels at the edge (d) and in the interior (e) of the particle.3 f) Schematic representation of a capillary reactor used for the MTO reaction, showing the crystallographic changes as a function of the catalyst bed height. The color scale (from blue to red) indicates an expansion of the crystallographic c axis with increasing time on stream.4 g) Scatter plot of a z‐scan of the MTO reaction in a large reactor, compared to a line plot from capillary reactor data. Images are adapted from Ref. 2–4.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4834627&req=5

fig1: Three recent reports are highlighted to show the potential of a multiscale science approach for studying heterogeneous catalysts at work with advanced X‐ray diffraction methods. a) An atomic model of a Pd surface during CO oxidation.2 b) A single diffraction image representing all of the images recorded during a rotational scan. Individual CTRs and superlattice rods are visible.2 c) Pd/Al2O3 catalyst body showing the particle size distribution measured by PDF‐CT.3 d, e) Experimental and fitted PDF data for single pixels at the edge (d) and in the interior (e) of the particle.3 f) Schematic representation of a capillary reactor used for the MTO reaction, showing the crystallographic changes as a function of the catalyst bed height. The color scale (from blue to red) indicates an expansion of the crystallographic c axis with increasing time on stream.4 g) Scatter plot of a z‐scan of the MTO reaction in a large reactor, compared to a line plot from capillary reactor data. Images are adapted from Ref. 2–4.
Mentions: The scientific community has recently celebrated the centennial of X‐ray diffraction. Ever since the first diffraction pattern was recorded by Max von Laue, X‐ray diffraction (XRD) has been developed into a widely used, powerful, and indispensable characterization method for structural analysis.1 A real revolution in using X‐rays for diffraction analysis happened with the advent of synchrotron radiation. Nowadays, numerous synchrotron facilities around the world provide highly brilliant, focused X‐rays with tunable energies. The energies of hard X‐rays (typically 5–100 keV) provide deep penetration into matter, which enables studies under elevated temperatures and pressures. Another benefit of hard X‐rays is that beam damage is significantly reduced. These features of hard X‐rays provide researchers with the ideal method to study catalysts under working conditions at different length scales, that is, at the level of the active surface of a catalyst material, of a catalyst body placed in a reactor, and of the chemical reactor itself. In this manner, it is possible to span a wide range of length scales, enabling a full multiscale science analysis of the dynamics of structurally complex catalytic materials. This highlight discusses the potential of modern hard X‐ray techniques to provide such a multiscale science approach for investigating heterogeneous catalysts at work by presenting some recent experiments that were the first of their kind (Figure 1).

View Article: PubMed Central - PubMed

Affiliation: Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht (The Netherlands).

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Ever since the first diffraction pattern was recorded by Max von Laue, X‐ray diffraction (XRD) has been developed into a widely used, powerful, and indispensable characterization method for structural analysis. 1 A real revolution in using X‐rays for diffraction analysis happened with the advent of synchrotron radiation... Nowadays, numerous synchrotron facilities around the world provide highly brilliant, focused X‐rays with tunable energies... The energies of hard X‐rays (typically 5–100 keV) provide deep penetration into matter, which enables studies under elevated temperatures and pressures... Another benefit of hard X‐rays is that beam damage is significantly reduced... These features of hard X‐rays provide researchers with the ideal method to study catalysts under working conditions at different length scales, that is, at the level of the active surface of a catalyst material, of a catalyst body placed in a reactor, and of the chemical reactor itself... By using a novel surface scattering geometry, Gustafson et al. 2 took advantage of high‐energy X‐rays (85 keV) by grazing incidence geometry... Surface scattering results in streaking of the Bragg reflections, a phenomenon that is due to the termination of the surface... Furthermore, scattered intensity and detector sensitivity drop with an increase in photon energy, whereas the time resolution of tomographic experiments is still a serious drawback for monitoring fast reaction processes... With the upgrades of the third‐generation synchrotrons, the performance of XRD has greatly improved over the past decade... These efforts should lead to even more significant improvements of the X‐ray beam brilliance and coherence, the speed and sensitivity of X‐ray detectors, and nano‐focusing optics... Considering also the potential of free electron lasers (FELs),5 one can only foresee a brilliant future for XRD in unravelling catalytic processes in detail and in bridging the molecular world with the macroscopic world.

No MeSH data available.


Related in: MedlinePlus