Atomic imaging of zeolite-confined single molecules by electron microscopy

Shen, Boyuan; Wang, Huiqiu; Xiong, Hao; Chen, Xiao; Bosch, Eric; Lazić, Ivan; Qian, Weizhong; Wei, Fei

doi:10.1038/s41586-022-04876-x

Cited by 63 publications

(49 citation statements)

References 40 publications

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“…30,31 While studying NCIs in supramolecular assemblies, one main challenge is to map and prove the presence of a particular NCI as they are dynamic, flexible, reversible, and sensitive to minor stimuli. To overcome this, the use of state-of-the-art surface science techniques such as atomic force microscopy (AFM) 32,33 scanning tunnelling microscopy (STM) 34 and their variants 32,35,36 as well as electron microscopy 37 have emerged as very useful methods because they allow a good understanding of NCIs at the molecular level with high resolution. Not only are they able to resolve the chemical structure of a single molecule, but they also assist in identifying different on-surface synthesized products, 38 and discriminate between spin states.…”

Section: Visualizing Ncis: a Formidable Taskmentioning

confidence: 99%

“…Not only are they able to resolve the chemical structure of a single molecule, but they also assist in identifying different on-surface synthesized products, 38 and discriminate between spin states. 35 In order to explore how small molecules interact with a porous material, Wei and co-workers 37 employed the integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM) technique to understand the behaviour of heterocyclic compounds such as pyridine within zeolite ZSM-5. They successfully imaged both the empty ZSM-5 and pyridine-saturated channels.…”

Section: Visualizing Ncis: a Formidable Taskmentioning

confidence: 99%

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Non-covalent interactions (NCIs) in π-conjugated functional materials: advances and perspectives

et al. 2023

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Section: Visualizing Ncis: a Formidable Taskmentioning

confidence: 99%

Section: Visualizing Ncis: a Formidable Taskmentioning

confidence: 99%

Non-covalent interactions (NCIs) in π-conjugated functional materials: advances and perspectives

et al. 2023

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“…Notably, Fig. 3d-i reveals that the in-situ formation of (Pt-Sn 2 ) 2 in the straight 10-membered ring channels essentially deforms the rings from nearly round to elliptical 25 , which is evidenced by the increased aspect ratio of d max /d min from 1.10 to 1.20. The formation of (Pt-Sn 2 ) 2 dimers within S-1(4.00 μm) crystals is also proven by Pt L 3 -edge EXAFS results inExtended Data Fig.…”

Section: B-e Andsupplementarymentioning

confidence: 97%

Migration-agglomeration-lockup of metal particles in zeolite for ultra-stable propane dehydrogenation catalysts

Zhu

Gao

et al. 2022

Preprint

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Propane dehydrogenation (PDH) over Pt catalyst operated in a moving-bed mode is becoming the dominant process for the on-purpose production of propylene worldwide1-3. Sintering and coking deactivations of Pt catalysts, which greatly decrease the durability and efficiency of this scarce and costly noble metal, are the most challenging issues for the sustainable development of the PDH process4. Even after over half a century of efforts, the development of long-term durable Pt catalysts that are feasible for more economic and efficient fixed-bed operation remains as a formidable task5-10. Herein we report a strategy to modulate the migration-agglomeration-lockup of Pt particles in zeolite silicalite-1 (S-1) for synthesizing highly sintering- and coking-resistant (Pt-Sn2)2@S-1 PDH catalysts. It is found that the migration of Pt-Sn2 clusters in S-1 crystals during the PDH reaction leads to a competition between intra-crystalline agglomeration and external-surface agglomeration of Pt-Sn2 clusters. We show that, when the b-axis length of S-1 crystals is longer than 2 μm, the intra-crystalline agglomeration becomes dominant over the external-surface agglomeration, resulting in the formation of ultra-stable (Pt-Sn2)2@S-1 in which the (Pt-Sn2)2 dimers are securely locked in the channels of S-1 crystals. The long-term durability (4500 hours or about 6 months on stream without perceptible deactivation tendency) of (Pt-Sn2)2@S-1 is at least three orders of magnitude higher than that of the best catalyst reported, which is expected to bring about a breakthrough in revolutionizing the moving-bed operation of the current PDH process to fixed-bed operation. We anticipate that modulating metal migration-agglomeration-lockup within zeolite can act as a general strategy for the synthesis of durable noble metal catalysts, which is beneficial to greatly maximizing the service lifetime of noble metals in industry application11-15.

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“…With innovation and continuous breakthroughs in experiments, theoretical simulations play an essential role in revealing the microscopic mechanism of the nanoconfinement effect and, mostly, are based on a static point of view. − Although theoretical simulations have also been performed from a dynamic perspective, , first-principles simulations regarding dynamic processes of confined species are still rarely carried out. However, previous works have demonstrated that certain critical information on the catalytic properties cannot be revealed unless one has performed systematic ab initio molecular dynamic simulations. − Also, considering that, currently, individual single molecules in confined nanoregions have been able to be directly observed by using advanced experimental techniques, − the time has thus come for in-depth investigations on the dynamic processes of confined species and corresponding mechanisms within the constrained microenvironments.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Construction and Maintenance of Confined Nanoregions via Hydrogen-Bond Networks between Acetylene Reactants and a Polyoxometalate-Based Metal–Organic Framework

2023

ACS Appl. Mater. Interfaces

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The nanoconfinement effect in catalysis has attracted much attention because it provides a novel means of regulating the molecular properties and related reactions. Confined nanoregions composed of both reactants and catalysts through weak interactions are expected to improve the catalytic performance and promote the mass transport of relevant molecules simultaneously. However, at reaction temperatures, the structural variation of such confined spaces constructed via weak interactions remains unclear. Herein, through density functional theory calculations combined with ab initio molecular dynamics simulations, we have systematically investigated the dynamic structural evolution of the confined space constructed by acetylene reactants and a polyoxometalate-based metal−organic framework (POMOF) via hydrogen-bond networks. It is found that, at the reaction temperature of acetylene semihydrogenation, the hydrogenbond networks and generated confined nanoregions are not rigid but are constantly changing and dynamically maintained. The steering role played by the O atoms at the surfaces of the polyoxometalate clusters is essential for generation of the hydrogen-bond networks and maintenance of the nanoregions. Upon confinement, the acetylene reactants can be better activated than those in an unconstrained atmosphere, which is reflected by the different dynamic distributions of the ∠CHC bending magnitude. Moreover, from a comparison of the distinct interaction characteristics between acetylene/ethylene and POMOF, the different manifestations in the adsorption energy variations of the confined molecules can be interpreted. This work helps to elucidate the underlying mechanisms of confined catalysis and may promote its application in practical catalytic processes.

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Atomic imaging of zeolite-confined single molecules by electron microscopy

Cited by 63 publications

References 40 publications

Non-covalent interactions (NCIs) in π-conjugated functional materials: advances and perspectives

Non-covalent interactions (NCIs) in π-conjugated functional materials: advances and perspectives

Migration-agglomeration-lockup of metal particles in zeolite for ultra-stable propane dehydrogenation catalysts

Dynamic Construction and Maintenance of Confined Nanoregions via Hydrogen-Bond Networks between Acetylene Reactants and a Polyoxometalate-Based Metal–Organic Framework

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