Super‐Resolution Reactivity Mapping of Nanostructured Catalyst Particles

Roeffaers, Maarten B. J.; Cremer, Gert De; Libeert, Julien; Ameloot, Rob; Dedecker, Peter; Bons, Anton‐Jan; Bückins, M.; Martens, Johan A.; Sels, Bert F.; Vos, Dirk De; Hofkens, Johan

doi:10.1002/anie.200904944

Cited by 183 publications

(217 citation statements)

References 45 publications

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“…With the intelligent molecular design of the optimal catalyst for a given process as the ultimate goal, more detailed molecular-level insights are a prerequisite. This is especially important to get track of elementary reactions at operating conditions, which is straightforward neither from experiment [8][9][10] nor from theory. 11,12 In modern society, oil derivatives are ubiquitous in daily life.…”

Section: Introductionmentioning

confidence: 99%

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Wispelaere

Bailleul

Speybroeck

2016

Catal. Sci. Technol.

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Title: Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions Advanced ab initio molecular dynamics techniques enable study of the infl uence of catalyst topology and acidity, reaction temperature and the presence of additional guest molecules on methylation reactions of benzene and propene, which are crucial reaction steps in the conversion of methanol into hydrocarbons. Our advanced simulations provide detailed insight into how operating conditions impact the competition of the concerted and stepwise methylation mechanism and thus the reaction kinetics. As featured in:See and mechanism of individual reaction steps at operating conditions. Herein we use state-of-the-art advanced ab initio molecular dynamics techniques to study the influence of catalyst topology and acidity, reaction temperature and the presence of additional guest molecules on elementary reactions. Such advanced modeling techniques provide complementary insight to experimental knowledge as the impact of individual factors on the reaction mechanism and kinetics of zeolite-catalyzed reactions may be unraveled. We study key reaction steps in the conversion of methanol to hydrocarbons, namely benzene and propene methylation. These reactions may occur either in a concerted or stepwise fashion, i.e. methanol directly transfers its methyl group to a hydrocarbon or the reaction goes through a framework-bound methoxide intermediate. The DFT-based dynamical approach enables mimicking reaction conditions as close as possible and studying the competition between two methylation mechanisms in an integrated fashion. The reactions are studied in the unidirectional AFI-structured H-SSZ-24, H-SAPO-5 and TON-structured H-ZSM-22 materials. We show that varying the temperature, topology, acidity and number of protic molecules surrounding the active site may tune the reaction mechanism at the molecular level. Obtaining molecular control is crucial in optimizing current zeolite processes and designing emerging new technologies bearing alternative feedstocks.

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Section: Introductionmentioning

confidence: 99%

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Wispelaere

Bailleul

Speybroeck

2016

Catal. Sci. Technol.

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“…Roeffaers et al used the liquid phase acid-catalyzed self-condensation of furfuryl alcohol in dioxane as a reporter reaction for imaging the catalytic activity of active sites in individual zeolite crystals [78,79]. After the condensation of the furfuryl alcohol, the reaction products entrapped in the pores are sufficiently fluorescent to be detected with a confocal microscope.…”

Section: Catalytic Reactivity Mapping In Porous Silica Compoundsmentioning

confidence: 99%

“…This anisotropy allows conclusions about the orientation of the emissive product molecules and hence the channel orientations within the zeolite crystals [78]. In another study, Roeffaers et al demonstrated the use of the same self-condensation reaction to study the reactive sites within ZSM-22 and ZSM-5 crystals with a new technique they called NASCA (nanometer accuracy by stochastic catalytic reactions) microscopy [79]. In this technique, 2D-Gaussian functions are fitted to the (diffraction-limited) emission spots of the fluorescent product molecules, and from these data, a high-resolution image is reconstructed that gives valuable information about the catalytic activity at different locations within the crystal (see Fig.…”

Section: Catalytic Reactivity Mapping In Porous Silica Compoundsmentioning

confidence: 99%

Review. Fluorescence Microscopy Studies of Porous Silica Materials

Rühle

Davies

Bein

et al. 2013

Zeitschrift Für Naturforschung B

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In this article, we discuss how fluorescence microscopy techniques are used to investigate important characteristics of porous silica materials. We start with a discussion of the synthesis, formation mechanism and functionalization of these materials. We then give an introduction to single molecule microscopy and show how this technique can be used to gain deeper insights into some defining properties of porous silica, such as pore structure, host-guest interactions and diffusion dynamics. We also provide examples from the literature demonstrating how fluorescence microscopy is used for elucidating important aspects of porous silica materials and heterogeneous catalysis, e. g. diffusion properties, reactivity, morphology, intergrowth, accessibility, and catalyst deactivation. Finally, a short outlook on the scope of porous silica hosts in drug delivery applications is given.

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“…[1][2][3][4] As in operando detection with fluorescence microscopy reaches the ultimate sensitivity limit of individual molecules and particles-and now of individual chemical reactions-an increasing number of chemists are designing experiments to gardener unique insights into catalysis and stoichiometric reactivity via this technique. Identification of the active phase of the catalyst in rutheniumcatalyzed polymerization, 5 mechanisms responsible for polymer morphology, 6 local environments in radical polymerization, 7,8 crystal face selectivity in surface hydrolysis of esters, 9 mechanistic steps in epoxidation of olefins, 10,11 heterogeneous reactivity of gold nanocatalysts, [12][13][14][15][16] protonation of amines, 17 surface spatial distribution with kinetics of ligand exchange reactions at platinum, [18][19][20][21][22] and ordering within nanomaterials 23 have provided the first applications in purely chemical systems unrelated to biology. 24 In order to image a chemical process, however, this chemical process needs to result in a change in fluorescent output that is detectable.…”

Section: Introductionmentioning

confidence: 99%

Location change method for imaging chemical reactivity and catalysis with single-molecule and -particle fluorescence microscopy

Blum

2014

Phys. Chem. Chem. Phys.

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In the last eight years, it has become possible to image chemical reactivity at the single-molecule and -particle level with fluorescence microscopy. This Perspective describes one of the imaging techniques that enabled this state-of-the-art application: imaging by the location change of molecules and particles. In this method, the microscope and experiment are configured to produce a signal when an individual molecule or particle changes location or changes mobility concurrently with a chemical change. This imaging technique has enabled observation of single chemical reactions and unraveled mechanisms of complex chemical and physical processes in transition metal and polymerization systems. This Perspective has three major goals:(1) to unify studies of different chemical processes or of different chemical questions, which, in spite of these differences, employ a similar microscopy detection method, (2) to explain the technique to nonexperts and those who might be interested in joining this nascent field, and (3) to highlight unique information available through this cross-disciplinary technique and the value this information has for chemical reaction development generally and catalysis specifically. To this end, application of the location change method to the investigation of polymerization reactions with radical initiators and separately with metal catalysts, and to ligand exchange reactions at platinum complexes are described.

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Super‐Resolution Reactivity Mapping of Nanostructured Catalyst Particles

Cited by 183 publications

References 45 publications

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Review. Fluorescence Microscopy Studies of Porous Silica Materials

Location change method for imaging chemical reactivity and catalysis with single-molecule and -particle fluorescence microscopy

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