High-Energy Surface X-ray Diffraction for Fast Surface Structure Determination

Gustafson, Johan; Shipilin, Mikhail; Zhang, Chu; Stierle, Andreas; Hejral, Uta; Ruett, Uta; Gutowski, Olof; Carlsson, Per-Anders; Skoglundh, Magnus; Lundgren, Edvin

doi:10.1126/science.1246834

Cited by 150 publications

(182 citation statements)

References 23 publications

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“…Indications of freezing in a well defined surface-science-style study could be obtained with e.g. ambient pressure x-ray photoelectron spectroscopy 113,114 or surface x-ray diffraction 115 . Another class of interesting materials are halogenated graphene 116,117 and graphane 118 .…”

Section: Future Perspective and Experimental Verificationmentioning

confidence: 99%

The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity

et al. 2015

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What makes a material a good ice nucleating agent? Despite the importance of heterogeneous ice nucleation to a variety of fields, from cloud science to microbiology, major gaps in our understanding of this ubiquitous process still prevent us from answering this question. In this work, we have examined the ability of generic crystalline substrates to promote ice nucleation as a function of the hydrophobicity and the morphology of the surface. Nucleation rates have been obtained by brute-force molecular dynamics simulations of coarse-grained water on top of different surfaces of a model fcc crystal, varying the watersurface interaction and the surface lattice parameter. It turns out that the lattice mismatch of the surface with respect to ice, customarily regarded as the most important requirement for a good ice nucleating agent, is at most desirable but not a requirement. On the other hand, the balance between the morphology of the surface and its hydrophobicity can significantly alter the ice nucleation rate and can also lead to the formation of up to three different faces of ice on the same substrate. We have pinpointed three circumstances where heterogeneous ice nucleation can be promoted by the crystalline surface: i) the formation of a water overlayer that acts as an in-plane template; ii) the emergence of a contact layer buckled in an ice-like manner; and iii) nucleation on compact surfaces with very high interaction strength. We hope that this extensive systematic study will foster future experimental work aimed at testing the physiochemical understanding presented herein.

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Section: Future Perspective and Experimental Verificationmentioning

confidence: 99%

The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity

et al. 2015

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“…In situ methods to characterize the state of the surface have recently been impressively advanced and begin to provide atomic-scale information at technologically relevant, (near-)ambient pressure conditions [2,[5][6][7][8][9][10][11] . Reaction-induced compositional and structural changes of the working catalyst are of particular interest.…”

Section: Introductionmentioning

confidence: 99%

Evidence for the Active Phase of Heterogeneous Catalysts through In Situ Reaction Product Imaging and Multiscale Modeling

Matera

Blomberg²,

Hoffmann

et al. 2015

ACS Catal.

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We use multi-scale modeling to analyze laser-induced fluorescence (LIF) measurements of the CO oxidation reaction over Pd(100) at near-ambient reaction conditions. Integrating density-functional theory based kinetic Monte Carlo simulations of the active catalyst into fluid-dynamical simulations of the mass transport inside the reactor chamber we calculate the reaction product concentration directly above the catalyst surface. Comparing corresponding data calculated for different surface models against the measured LIF signals we can discriminate the one that predominantly actuates the experimentally measured catalytic activity. For the probed CO oxidation reaction conditions the experimental activity is due to pristine Pd(100), possibly coexisting with other (oxidic) domains on the surface.

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“…We exploit the full potential of X‐rays22, 23, 24, 25, 26, 27, 28, 29 by using one X‐ray beam to acquire both diffraction and spectral information. The local zeolite crystallinity, as measured by μ‐XRD, is correlated with the local presence of Brønsted acidity, as measured by μ‐XEOF.…”

mentioning

confidence: 99%

X‐ray Excited Optical Fluorescence and Diffraction Imaging of Reactivity and Crystallinity in a Zeolite Crystal: Crystallography and Molecular Spectroscopy in One

et al. 2016

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Structure–activity relationships in heterogeneous catalysis are challenging to be measured on a single‐particle level. For the first time, one X‐ray beam is used to determine the crystallographic structure and reactivity of a single zeolite crystal. The method generates μm‐resolved X‐ray diffraction (μ‐XRD) and X‐ray excited optical fluorescence (μ‐XEOF) maps of the crystallinity and Brønsted reactivity of a zeolite crystal previously reacted with a styrene probe molecule. The local gradients in chemical reactivity (derived from μ‐XEOF) were correlated with local crystallinity and framework Al content, determined by μ‐XRD. Two distinctly different types of fluorescent species formed selectively, depending on the local zeolite crystallinity. The results illustrate the potential of this approach to resolve the crystallographic structure of a porous material and its reactivity in one experiment via X‐ray induced fluorescence of organic molecules formed at the reactive centers.

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High-Energy Surface X-ray Diffraction for Fast Surface Structure Determination

Cited by 150 publications

References 23 publications

The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity

The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity

Evidence for the Active Phase of Heterogeneous Catalysts through In Situ Reaction Product Imaging and Multiscale Modeling

X‐ray Excited Optical Fluorescence and Diffraction Imaging of Reactivity and Crystallinity in a Zeolite Crystal: Crystallography and Molecular Spectroscopy in One

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