Tailoring Pt locations in KL zeolite by improved atomic layer deposition for excellent performance in n-heptane aromatization

Xu, Di; Wang, Shuyuan; Wu, Baoshan; Huo, Chun‐Fang; Qin, Yong; Zhang, Bin; Yin, Junqing; Huang, Lihua; Wen, Xiaodong; Yang, Yong; Li, Yongwang

doi:10.1016/j.jcat.2018.07.001

Cited by 35 publications

(45 citation statements)

References 68 publications

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“…It has been well established that, subnanometric Pt clusters confined in the 12MR channels of KLTL zeolite are the active sites for dehydrocyclization of alkanes (C6-C8) to aromatics 153,154 . The Pt/KLTL catalyst with Pt clusters of 0.6-0.7 nm shows higher selectivity to aromatics and lower deactivation rate for conversion of n-heptane to benzene and toluene 155 .…”

Section: Dehydrogenation Of Alkanesmentioning

confidence: 99%

Confining isolated atoms and clusters in crystalline porous materials for catalysis

2020

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The recent works on supported isolated metal atoms and metal clusters with a few atoms have reformed our understanding on the structure-reactivity relationship established on conventional nanoparticulate catalysts. One critical issue related to supported subnanometric metal catalysts (including both isolated atoms and clusters) on conventional open-structure carriers is the stability of the metal entities, since they may sinter into large nanoparticles under harsh reaction conditions. By confining the isolated metal atoms or subnanometric metal clusters in crystalline porous materials (such as zeolites and metal-organic frameworks) can improve the stability of these tiny species against sintering into nanoparticles. More importantly, the interaction between the metal species and the porous framework may modulate the geometric and electronic structures of the subnanometric metal species, especially in the cases of metal clusters. Such confinement effect can induce shape-selective catalysis or unique chemoselectivity compared to the counterpart metal entities supported on conventional open-structure solid carriers. In this review, we will discuss the structural features, synthesis methodologies, characterization techniques and catalytic applications of subnanometric species confined in zeolites and metal-organic frameworks, aiming to make critical comparison between confined and un-confined isolated atoms and metal clusters and to give perspectives on the future developments.

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Section: Dehydrogenation Of Alkanesmentioning

confidence: 99%

Confining isolated atoms and clusters in crystalline porous materials for catalysis

2020

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“…5,13 Recently, our work indicated that Pt clusters trapped within zeolite channels could reduce the energy barrier of C–H bond cleavage during 1,6-ring closure of alkanes, resulting in high catalytic activity and aromatic selectivity. 18 Similarly, He and Song et al 19,20 confirmed that Pt clusters within the pores of zeolite were beneficial to the n -alkane cyclization due to the assistance of the channel architecture. Although elucidation of the excellent aromatization ability of Pt/KL catalysts remained controversial, it was not denied that KL zeolite channel architecture plays an indispensable role in enhancing the catalytic performance during n -alkane aromatization.…”

Section: Introductionmentioning

confidence: 93%

Insight into the performance of different Pt/KL catalysts for n-alkane (C6–C8) aromatization: catalytic role of zeolite channels

Yan

et al. 2022

Catal. Sci. Technol.

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“…Therefore, FXBID could be useful for the functionalization of porous substrates or buried structures with the only limitation that the precursor gas has to reach the intended deposition zone. Deposition in the depth of (nano)porous substrates is a common task in recent atomic layer deposition (ALD) studies targeting on highly reactive catalysts or absorbing agents with extra-large surfaces [120][121][122][123][124][125][126]. FXBID could also be used in terms of a photon assisted ALD process and contribute to increased functionalization rates, deposition from otherwise too stable precursors and spatially confined functionalization.…”

Section: Perspectives Or: What Fxbid Might Be Good Formentioning

confidence: 99%

Additive Nano-Lithography with Focused Soft X-rays: Basics, Challenges, and Opportunities

Späth

2019

Micromachines

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Focused soft X-ray beam induced deposition (FXBID) is a novel technique for direct-write nanofabrication of metallic nanostructures from metal organic precursor gases. It combines the established concepts of focused electron beam induced processing (FEBIP) and X-ray lithography (XRL). The present setup is based on a scanning transmission X-ray microscope (STXM) equipped with a gas flow cell to provide metal organic precursor molecules towards the intended deposition zone. Fundamentals of X-ray microscopy instrumentation and X-ray radiation chemistry relevant for FXBID development are presented in a comprehensive form. Recently published proof-of-concept studies on initial experiments on FXBID nanolithography are reviewed for an overview on current progress and proposed advances of nanofabrication performance. Potential applications and advantages of FXBID are discussed with respect to competing electron/ion based techniques. polymer resulting in 3D patterning by radiation chemistry [33,34]. The approach is limited to materials with significantly different absorption cross-sections at the chosen incident photon energies, as in transmission geometry, all layers are exposed to the beam at different degrees of focusing. However, such experiments open a completely novel perspective for complex direct-write nanofabrication. It should be mentioned that during the late 1980s and early 1990s several groups attempted to exploit broad-band synchrotron light [38][39][40][41] as well as the monochromatic X-ray beam of a photon-induced scanning Auger microscope [42,43] for additive manufacturing of metal deposits from metal organic precursors. However, due to limited instrumental capabilities, only spatially extended thin films with an optimum of some 10 µm resolution could be produced [43].FXBID exploits the photon energy-selectivity of synchrotron-based XRL and extends it by the idea of depositing metal nanostructures from suitable precursor gases [21,22]. The use of a STXM setup for these experiments offers several advantages. STXM is a raster-scanning technique which avoids the necessity of shadow masks. According to comparable results from polymer lithography the theoretical minimum feature size of the deposited metal structures is mainly determined by the spot size of the incident beam [36,37]. Recent developments in X-ray optics have pushed this parameter below 10 nm [44,45]. Finally, STXM can be employed for an in-situ analysis of the metallic deposits directly after fabrication by means of resonant imaging and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to evaluate confinement, growth rates, oxidation state and chemical purity [21,22,46,47]. X-ray magnetic circular dichroism (XMCD) can be used to characterize magnetic deposits with respect to their magnetization and coercivity [48].This review presents some basic principles of X-ray optics and X-ray microscopy as well as X-ray beam dosimetry that are relevant for FXBID experiments. In accordance, limitations, challenges and opportunities of additiv...

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Tailoring Pt locations in KL zeolite by improved atomic layer deposition for excellent performance in n-heptane aromatization

Cited by 35 publications

References 68 publications

Confining isolated atoms and clusters in crystalline porous materials for catalysis

Confining isolated atoms and clusters in crystalline porous materials for catalysis

Insight into the performance of different Pt/KL catalysts for n-alkane (C6–C8) aromatization: catalytic role of zeolite channels

Additive Nano-Lithography with Focused Soft X-rays: Basics, Challenges, and Opportunities

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