ZSM‐5 Zeolite Nanosheets with Improved Catalytic Activity Synthesized Using a New Class of Structure‐Directing Agents

Kore, Rajkumar; Srivastava, Rajendra; Satpati, Biswarup

doi:10.1002/chem.201402665

Cited by 65 publications

(53 citation statements)

References 84 publications

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“…Increased activity of MWW layered zeolites in the alkylation of aromatics was explained by a high number of surface pockets containing accessible acid centers. Yet another 2D zeolite consisting of MWW monolayers arranged into the “house‐of‐cards” architecture (MIT‐1) showed 3 times higher activity in alkylation of benzene with benzyl alcohol compared to 3D MWW (MCM‐22) and 2D MWW (MCM‐56) counterparts, which correlated with decreasing external surface area (513, 219, and 121 m 2 g −1 for MIT‐1, MCM‐56, and MCM‐22, respectively) and concentration of surface acid sites determined by 31 P MAS NMR using trimethylphosphine and tributylphosphine oxides (210, 130, and 60 µmol g −1 for MIT‐1, MCM‐56, and MCM‐22, respectively) …”

Section: D Zeolitesmentioning

confidence: 99%

2D Oxide Nanomaterials to Address the Energy Transition and Catalysis

et al. 2018

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2D oxide nanomaterials constitute a broad range of materials, with a wide array of current and potential applications, particularly in the fields of energy storage and catalysis for sustainable energy production. Despite the many similarities in structure, composition, and synthetic methods and uses, the current literature on layered oxides is diverse and disconnected. A number of reviews can be found in the literature, but they are mostly focused on one of the particular subclasses of 2D oxides. This review attempts to bridge the knowledge gap between individual layered oxide types by summarizing recent developments in all important 2D oxide systems including supported ultrathin oxide films, layered clays and double hydroxides, layered perovskites, and novel 2D-zeolite-based materials. Particular attention is paid to the underlying similarities and differences between the various materials, and the subsequent challenges faced by each research community. The potential of layered oxides toward future applications is critically evaluated, especially in the areas of electrocatalysis and photocatalysis, biomass conversion, and fine chemical synthesis. Attention is also paid to corresponding novel 3D materials that can be obtained via sophisticated engineering of 2D oxides.

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Section: D Zeolitesmentioning

confidence: 99%

2D Oxide Nanomaterials to Address the Energy Transition and Catalysis

et al. 2018

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“…Besides, the surface silanols of the pure-silica MFI nanosheets were demonstrated to be useful for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam, an important intermediate for the synthesis of Nylon-6. Owing to the contribution of strong acid sites located on the external surface accessible for the reaction of bulky reactants, the hierarchical MFI nanosheets were also suitable for Friedel-Crafts alkylation, [ 134 ] acylation reactions, [ 135 ] and dehydration reactions [ 136 ] etc. Owing to the contribution of strong acid sites located on the external surface accessible for the reaction of bulky reactants, the hierarchical MFI nanosheets were also suitable for Friedel-Crafts alkylation, [ 134 ] acylation reactions, [ 135 ] and dehydration reactions [ 136 ] etc.…”

Section: Acid-catalyzed Reactionsmentioning

confidence: 99%

Recent Advances in the Synthesis and Application of Two‐Dimensional Zeolites

Sun

2016

Advanced Energy Materials

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traditional hydrothermal syntheses would produce intermediate materials with 2D feature, such as MCM-22P, [ 7,8 ] PREFER, [ 9 ] which are composed of crystalline zeolite layers with the unit-cell thickness stacking on top of each other in ordered or disordered patterns. [10][11][12][13][14][15] Unlike traditional 3D zeolites, the crystal growth of frameworks in 2D layered zeolites is restricted in one particular direction, leaving lots of hydroxyl groups on layer surface. As zeolites are normally defi ned as 3D materials that possess regular micropore systems and consist of TO 4 tetrahedra, layered zeolite precursors containing silanols could not be regarded as zeolites in the strictest sense, but they are broadly included in the family of zeolite materials. Thus, the as-synthesized 2D zeolites are often denoted as layered zeolite precursors (the typical examples are shown in Table 1 ), [7][8][9] which would transform into their 3D order/disorder counterparts after removing organic molecules and condesation of interlayer silanols via calcination. [ 10 ] In the early research stage, the layered zeolite precursors are discovered accidentally in traditional hydrothermal syntheses, because we have limited control over the traditional synthesis process due to the incomplete understanding of crystallization mechanism. At that stage, one of the most attractive features of 2D zeolites is that they could transform into zeolite materials with hierarchical architectures. In some cases, the traditional synthesis produces hierarchical layered material, such as MCM-56, [ 26 ] in which the crystalline zeolite layers disorderly stacked. Furthermore, the recognition that the obtained layered precursors could be modifi ed into various hierarchical zeolite structures (such as delaminated, pillared, interlayer expanded and others) make them signifi cantly different from conventional 3D zeolite materials with rigid structures. Thus, the construction of hierarchical zeolite materials from the perspective of 2D layered zeolite precursors is an important research aspect during the past few years.With the improved synthetic techniques, layered zeolites are not only increasing in number, but also expanding the notion in composition and structure. One remarkable breakthrough in recent years is the discovery of 2D MFI nanosheets with the single unit-cell thickness (about 2 nm), which is achieved by adopting Gemini-type bifunctional surfactants as organic structure-directing agent (OSDA) in hydrothermal synthesis. [ 49 ] The calcined MFI nanosheets become a special kind of hierarchical zeolites Two-dimensional (2D) zeolites, originating from lamellar precursors, are a special kind of porous materials, in which crystalline zeolite nanolayers are weakly assembled in one particular direction. As there is no covalentbond between layers, the stacking sequences could be manipulated and possibly controlled to derive a family of zeolitic materials with structural diversity. The research on 2D zeolites arises from the primary casual discovery during ...

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“…Efforts have been made to develop soft and hard templates mediated synthesis of mesoporous zeolites [30]. Our group has also developed several soft-templates based synthesis methodologies to prepare nanocrystalline/mesoporous zeolites of different framework structures [31,32] Biomineralization is a well-known process known to facilitate the growth of HAP using simulated body fluid (SBF) that contains inorganic ion concentrations nearly equal to those of human blood plasma [33,34]. Biomineralization involves the initial nucleation and subsequent growth of HAP from aqueous SBF on the surface of material [35].…”

Section: Introductionmentioning

confidence: 99%