Quantification of external surface and pore mouth acid sites in unit-cell thick pillared MFI and pillared MWW zeolites

Wu, Yiqing; Emdadi, Laleh; Qin, Dongchang; Zhang, Junyan; Liu, Dongxia

doi:10.1016/j.micromeso.2016.12.004

Cited by 25 publications

(32 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The formation of the alkylation product, 1,3,5‐trimethyl‐2‐benzylbenzene, was found to be inhibited and eventually completely suppressed when an excess amount of dTBP was added in the reaction mixture . Since dTBP only deactivates BASs on the external surface of MFI, it can be concluded that only the external BASs of SPP are accessible to catalyze the alkylation reaction. Control experiments were carried out using pure‐silica SPP (a pure‐silica zeolite with SPP structure), γ‐alumina (a Lewis acid catalyst), and Sn‐SPP (a Lewis acid zeolite with SPP structure).…”

Section: Resultsmentioning

confidence: 99%

A quantitative study of the structure–activity relationship in hierarchical zeolites using liquid‐phase reactions

Abdelrahman

Ahn

et al. 2019

AIChE Journal

Self Cite

View full text Add to dashboard Cite

Instructions for contributors Inside back coverCover illustration. Hierarchical zeolites made of intergrown nanosheets offer short diffusion lengths allowing for catalytic reactions to proceed in the zeolite micropores in the absence of diffusion limitations. At the same time, catalysis of desirable or undesirable reactions can take place in the mesopores. Using a model reaction and by systematic variation of nanosheet thickness with nanometer (single-unit-cell) precision, it is demonstrated that reaction-diffusion in micro-/meso-porous zeolites can be quantitatively analyzed by mathematical modelling, and finetuned towards a desirable product distribution. Images courtesy of Dandan

show abstract

Section: Resultsmentioning

confidence: 99%

A quantitative study of the structure–activity relationship in hierarchical zeolites using liquid‐phase reactions

Abdelrahman

Ahn

et al. 2019

AIChE Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…The acid site accessibility of pillared MFI and SPP zeolites has been measured by direct DTBP uptake measurements, which maintain the characteristics of the high acid site accessibility in 2D MFI zeolites [173,245,251,252]. In particular, the concentrations of external surface and pore mouth Brønsted acid sites in the pillared MFI zeolite was quantified by a combined dimethyl ether (DME) titration and methanol dehydration in the presence of DTBP or triphenylphosphine (TPP) titrants, respectively [232]. DME can access all Brønsted acid sites in pillared MFI zeolites and thus determine the total number of acid sites.…”

Section: Acidity Characterization For 2d Mfi Zeolitesmentioning

confidence: 99%

“…It can solely access the acid sites on the external surface [271]. The decrease in methanol dehydration rate in the presence of TPP titrant reflects the fractions of external surface and/or pore mouth acid sites in MCM-36 zeolite, where it consists of ∼33% external surface and ∼31% pore mouth acid sites [232]. 31 P MAS NMR spectroscopy was used to analyze acid site locations in the 2D MIT-1 structure [67].…”

Section: Acidity Characterization For 2d Mww Zeolitesmentioning

confidence: 99%

Two-Dimensional Zeolite Materials: Structural and Acidity Properties

Schulman

Liu

2020

Materials

Self Cite

View full text Add to dashboard Cite

Zeolites are generally defined as three-dimensional (3D) crystalline microporous aluminosilicates in which silicon (Si4+) and aluminum (Al3+) are coordinated tetrahedrally with oxygen to form large negative lattices and consequent Brønsted acidity. Two-dimensional (2D) zeolite nanosheets with single-unit-cell or near single-unit-cell thickness (~2–3 nm) represent an emerging type of zeolite material. The extremely thin slices of crystals in 2D zeolites produce high external surface areas (up to 50% of total surface area compared to ~2% in micron-sized 3D zeolite) and expose most of their active sites on external surfaces, enabling beneficial effects for the adsorption and reaction performance for processing bulky molecules. This review summarizes the structural properties of 2D layered precursors and 2D zeolite derivatives, as well as the acidity properties of 2D zeolite derivative structures, especially in connection to their 3D conventional zeolite analogues’ structural and compositional properties. The timeline of the synthesis and recognition of 2D zeolites, as well as the structure and composition properties of each 2D zeolite, are discussed initially. The qualitative and quantitative measurements on the acid site type, strength, and accessibility of 2D zeolites are then presented. Future research and development directions to advance understanding of 2D zeolite materials are also discussed.

show abstract

“…A deeper differentiation and quantification of external acid sites located on the external surface or at the pore mouth regions in pillared MFI and MWW materials was performed by Wu et al In addition to the titration with dimethyl ether to evaluate overall acid site concentration, methanol dehydration in the presence of 2,6‐di‐ tert ‐butylpyridine or triphenylphosphine was tested. While 2,6‐di‐ tert ‐butylpyridine (with a diameter of 7.9 Å) can access both the acid sites on external surface and at the pore mouths, triphenylphosphine (with a diameter of 9.4 Å) can only access the former.…”

Section: D Zeolitesmentioning

confidence: 99%

2D Oxide Nanomaterials to Address the Energy Transition and Catalysis

et al. 2018

View full text Add to dashboard Cite

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.

show abstract

Quantification of external surface and pore mouth acid sites in unit-cell thick pillared MFI and pillared MWW zeolites

Cited by 25 publications

References 59 publications

A quantitative study of the structure–activity relationship in hierarchical zeolites using liquid‐phase reactions

A quantitative study of the structure–activity relationship in hierarchical zeolites using liquid‐phase reactions

Two-Dimensional Zeolite Materials: Structural and Acidity Properties

2D Oxide Nanomaterials to Address the Energy Transition and Catalysis

Contact Info

Product

Resources

About