Controllable fabrication of single-crystalline, ultrafine and high-silica hierarchical ZSM-5 aggregates via solid-like state conversion

Li, Hongyao; Wang, Yaquan; Meng, Fanjun; Gao, Fei; Sun, Chao; Fan, Chunyang; Wang, Xiao; Wang, Shuhai

doi:10.1039/c7ra03962j

Cited by 22 publications

(4 citation statements)

References 67 publications

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“…The finding of this work supports the occurrence of a kinetics-controlled dissolution/induction/growth/aggregation mechanism. [195] For economic and ecological reasons, seeding methods without use of organic mesoporogens have been proposed. Zhang et al studied a seed-induced method in combination with a salt-aided route.…”

Section: Zsm-5mentioning

confidence: 99%

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State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

et al. 2020

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Zeolites are highly crystalline aluminosilicates with welldefined pores that are constructed of SiO 2 and AlO 4 tetrahedra. These tetrahedra can be linked together in different unique ways to form various materials with a specific topology. [1] According to the International Zeolite Association (IZA), more than 250 different topologies, which are all assigned with a three-letter code, have been identified. [2] The micropores in zeolites are typically constructed from 8, 10, or 12 tetrahedral atoms

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Section: Zsm-5mentioning

confidence: 99%

“…The finding of this work supports the occurrence of a kinetics‐controlled dissolution/induction/growth/aggregation mechanism. [ 195 ]…”

Section: Synthesis Of Hierarchical 10‐mr Zeolitesmentioning

confidence: 99%

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

et al. 2020

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“…The hierarchical ZSM-5 catalyst showed higher propylene (40.1%), higher butylene (22.9%) selectivities, and had a significantly longer catalytic lifetime (22 h) compared to the commercial ZSM-5 zeolite. This may refer to the mesoporosity, which increases the external surface and reduces diffusion path lengths, resulting in the utilization of acid sites and preventing further reactions and coke formation [60]. Moreover, the seed-fused ZSM-5 nanosheet (CNS) was synthesized by introducing 5 wt.…”

Section: Methanol and Ethanol To Light Olefinsmentioning

confidence: 99%

A Comprehensive Review of the Applications of Hierarchical Zeolite Nanosheets and Nanoparticle Assemblies in Light Olefin Production

Dugkhuntod

Wattanakit

2020

Catalysts

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Light olefins including ethylene, propylene and butylene are important building blocks in petrochemical industries to produce various chemicals such as polyethylene, polypropylene, ethylene oxide and cumene. Traditionally, light olefins are produced via a steam cracking process operated at an extremely high temperature. The catalytic conversion, in which zeolites have been widely used, is an alternative pathway using a lower temperature. However, conventional zeolites, composed of a pure microporous structure, restrict the diffusion of large molecules into the framework, resulting in coke formation and further side reactions. To overcome these problems, hierarchical zeolites composed of additional mesoporous and/or macroporous structures have been widely researched over the past decade. In this review, the recent development of hierarchical zeolite nanosheets and nanoparticle assemblies together with opening up their applications in various light olefin productions such as catalytic cracking, ethanol dehydration to ethylene, methanol to olefins (MTO) and other reactions will be presented.Catalysts 2020, 10, 245 2 of 15 windows, they can be divided into three different categories including large porous, medium porous and small porous zeolites, which are composed of a different number of tetrahedral units, or T atoms of 12, 10 and 8 membered rings, respectively. These behaviors make each zeolite serving unique shape selective properties, which are very important for the appropriate applications.Although there are several above-mentioned promising properties of zeolites, they are typically composed of a very small microporous structure, eventually resulting in some disadvantages of the diffusion limitation of guest molecules inside the framework. Some bulky molecules cannot easily penetrate into active sites located at microporous channels, and therefore a poor catalytic performance due to a very low reaction rate and a fast deactivation of catalysts is observed. To overcome these limitations and to improve the accessibility of molecules into active sites, in recent years modified zeolites obtained by introducing additional larger porous structures have been extensively developed [5][6][7][8].It is well known that hierarchical zeolites, composed of at least two levels of porous structures such as microspores and mesopores, microspores and macropores, and micropores/mesopores and macropores have been extensively studied and developed. Their microporous (<2 nm), mesoporous (2-50 nm) and/or macroporous (>50 nm) structures are well connected to each other. In this case, the additional larger porous structures can improve diffusion limitation, molecular transportation and coke deposition [9]. In the past decade, there have been several studies regarding the synthesis of hierarchical zeolites to overcome these problems. Herein, this comprehensive review opens up perspectives of the recent synthesis approaches of hierarchical zeolite nanosheets and nanoparticle assemblies, as well as the successful production of light olef...

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“…Zeolites, a kind of microporous crystalline aluminosilicates, have been widely applied in the fields of adsorption, separation, and catalysis in petrochemical and chemical industry . Aiming to the functionalization of host zeolite matrixes, various guest species are added into the precursor of zeolites, in which the nucleation and growth of zeolite crystals occur together with guest species .…”

Section: Introductionmentioning

confidence: 99%

CoFe₂O₄ Nanocrystals Mediated Crystallization Strategy for Magnetic Functioned ZSM‐5 Catalysts

Yıldırım

et al. 2018

Adv Funct Materials

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Zeolites have many applications in the petrochemical and fine chemical industry and their functionalization does expand the spectrum of potentials. However, the integration of functional nanocrystals into zeolite frameworks with controlled size, dispersion, and crystallization behavior still remains a significant challenge. Here, a new synthesis of magnetic functioned ZSM-5 zeolite catalysts via a CoFe 2 O 4 nanocrystal mediated crystallization strategy is reported. It is found that high crystallinity of CoFe 2 O 4 nanocrystals results in a well-dispersed encapsulation of them into a single-crystal of ZSM-5 due to non-further-grown nanocrystals during the fast ZSM-5 growth. On the contrary, low crystallinity of CoFe 2 O 4 nanocrystals leads to the polycrystalline zeolite growth due to the secondary growth of nanocrystals accompanied by the zeolite crystallization and large lattice mismatch between them. The successful encapsulation of small CoFe 2 O 4 nanocrystals (≈4 nm) into single crystals lies on the preattachment of them into solid silica gel. During the growth of ZSM-5 crystals, no secondary growth of nanocrystals happens and its motion is restricted. The encapsulation of magnetic CoFe 2 O 4 nanocrystals not only endows magnetic function into zeolites for the first time, but also does not impact catalytic performance of ZSM-5 in acetalization of cyclohexanone with methanol, which is highly promising in catalytic industries.

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Controllable fabrication of single-crystalline, ultrafine and high-silica hierarchical ZSM-5 aggregates via solid-like state conversion

Abstract: Single-crystalline, ultrafine and high-silica HA-ZSM-5 aggregates were directly synthesizedviaSSC method using HTAB as the mesoporogen through a S-1 seed-induced route.

Cited by 22 publications

References 67 publications

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

A Comprehensive Review of the Applications of Hierarchical Zeolite Nanosheets and Nanoparticle Assemblies in Light Olefin Production

CoFe₂O₄ Nanocrystals Mediated Crystallization Strategy for Magnetic Functioned ZSM‐5 Catalysts

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Controllable fabrication of single-crystalline, ultrafine and high-silica hierarchical ZSM-5 aggregates via solid-like state conversion

Abstract: Single-crystalline, ultrafine and high-silica HA-ZSM-5 aggregates were directly synthesizedviaSSC method using HTAB as the mesoporogen through a S-1 seed-induced route.

Cited by 22 publications

References 67 publications

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

A Comprehensive Review of the Applications of Hierarchical Zeolite Nanosheets and Nanoparticle Assemblies in Light Olefin Production

CoFe2O4 Nanocrystals Mediated Crystallization Strategy for Magnetic Functioned ZSM‐5 Catalysts

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CoFe₂O₄ Nanocrystals Mediated Crystallization Strategy for Magnetic Functioned ZSM‐5 Catalysts