Facile preparation of nanocrystal-assembled hierarchical mordenite zeolites with remarkable catalytic performance

Yuan, Yangyang; Wang, Linying; Liu, Hongchao; Tian, Peng; Yang, Miao; Xu, Shutao; Liu, Zhongmin

doi:10.1016/s1872-2067(15)60960-3

Cited by 59 publications

(32 citation statements)

References 50 publications

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“…Generally, organosilanes and mono‐ or multi‐quaternary ammonium salts have been employed to introduce mesoporosity in MOR zeolite. Nearly all of the described recipes involve the addition of a mesoporogen to a synthesis mixture which contains seeds, conventional SDAs, or require complex cationic surfactants with two or more ammonium ions . There are only few reports that claim the formation of hierarchical MOR zeolite with a mono‐quaternary ammonium surfactant or aniline as a single SDA .…”

Section: Introductionmentioning

confidence: 99%

Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

et al. 2019

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We report the synthesis of hierarchical mordenite zeolite nanorods in one step using inexpensive mono‐quaternary ammonium N‐cetyl‐N‐methylpyrrolidinium (C16NMP) as mesoporogen to the synthesis gel. The presence of a small amount of C16NMP results in the formation of 0.6–1 μm rods‐like crystals oriented along the c‐axis with a high mesoporous volume (0.12 cm3 g−1) and external surface area (∼90 m2 g−1) compared to bulk mordenite. Acidity characterization shows that the presence of C16NMP during mordenite formation leads to a redistribution of aluminum in the zeolite framework: the amount of Brønsted acid sites in the side‐pockets (8MR channels) is increased at the expense of those in the 12MR main channels. As these latter acid sites are the ones involved in the conversion of alkene intermediates in bifunctional hydroconversion of alkanes, an optimized hierarchical mordenite prepared with C16NMP displays a more ideal hydrocracking selectivity than bulk MOR prepared solely with sodium.

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Section: Introductionmentioning

confidence: 99%

Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

et al. 2019

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“…The protocol of synthesis of hierarchical MOR-type zeolite was adapted from the protocol published by Yuan et al [ 41 ]. This protocol requires the use of several organic additives (tetraethyl ammonium hydroxide (TEAOH), CTAB, sodium dodecylbenzene sulfonate surfactant (SDBS), etc) whereas, in our protocol, only CTAB is used as a porogen agent.…”

Section: Methodsmentioning

confidence: 99%

“…The introduction of organic bases in the synthesis medium allowed obtaining mordenite with SiO 2 /Al 2 O 3 ratios from 20 to 40 [ 36 ]. Recently, several studies were devoted to the synthesis of hierarchical MOR-type zeolite with reduced diffusion path length [ 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. These strategies consisted on the use of sacrificial templates such as organosilanes [ 37 , 38 , 39 ] or hexadecyltrimethylammonium bromide (CTAB) [ 40 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Hierarchical MOR-Type Zeolites with Improved Catalytic Properties

et al. 2021

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Hierarchical MOR-type zeolites were synthesized in the presence of hexadecyltrimethylammonium bromide (CTAB) as a porogen agent. XRD proved that the concentration of CTAB in the synthesis medium plays an essential role in forming pure hierarchical MOR-type material. Above a CTAB concentration of 0.04 mol·L−1, amorphous materials are observed. These hierarchical mordenite possess a higher porous volume compared to its counterpart conventional micrometer crystals. Nitrogen sorption showed the presence of mesoporosity for all mordenite samples synthesized in the presence of CTAB. The creation of mesopores due to the presence of CTAB in the synthesis medium does not occur at the expense of zeolite micropores. In addition, mesoporous volume and BET surface seem to increase upon the increase of CTAB concentration in the synthesis medium. The Si/Al ratio of the zeolite framework can be increased from 5.5 to 9.1 by halving the aluminum content present in the synthesis gel. These synthesized hierarchical MOR-type zeolites possess an improved catalytic activity for n-hexane cracking compared to large zeolite crystals obtained in the absence of CTAB.

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“…[19] Thus, exposing more 8-MR windows by reducing the thickness along the b axis of the MOR topology would achieve specific catalytic selectivity. The MOR nanocrystals with 20-50 nm dimensions have been fabricated by using the amphiphilic templates with multiquaternary ammonium heads [13] or the combination of tetraethyl ammonium hydroxide and commercial amphiphilic surfactants, [20] but the crystal orientation and size were uncontrollable. Shen et al synthesized the MOR nanosheets with of 20-40 nm thickness along the c axis using a single quaternary ammonium surfactant.…”

mentioning

confidence: 99%

High Ethylene Selectivity in Methanol‐to‐Olefin (MTO) Reaction over MOR‐Zeolite Nanosheets

Lu,

Huang,

Ren

et al. 2020

Angew Chem Int Ed

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Precisely controlled crystal growth endows zeolites with special textural and catalytic properties. A nanosheet mordenite zeolite with a thickness of ca. 11 nm, named as MOR‐NS, has been prepared using a well‐designed gemini‐type amphiphilic surfactant as bifunctional structure‐directing agent (SDA). Its benzyl diquarternary ammonium cations structurally directed the formation of MOR topology, whereas the long and hydrophobic hexadecyl tailing group prevented the extensive crystal growth along b axis. This kind of orientated crystallization took place through the inorganic–organic interaction between silica species and SDA molecules present in the whole process. The thin MOR nanosheets, with highly exposed (010) planes and 8‐membered ring (MR) windows, exhibited a much improved ethylene selectivity (42.1 %) for methanol‐to‐olefin (MTO) reactions when compared with conventional bulk MOR crystals (3.3 %).

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Facile preparation of nanocrystal-assembled hierarchical mordenite zeolites with remarkable catalytic performance

Cited by 59 publications

References 50 publications

Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

Synthesis of Hierarchical MOR-Type Zeolites with Improved Catalytic Properties

High Ethylene Selectivity in Methanol‐to‐Olefin (MTO) Reaction over MOR‐Zeolite Nanosheets

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