Structure Analysis of the Mesopore in Dealuminated Zeolite Y by High Resolution TEM Observation with Slow Scan CCD Camera

Sasaki, Yukichi; Suzuki, Toshiyuki; Takamura, Yukihiro; Saji, Akira; Saka, Hiroyasu

doi:10.1006/jcat.1998.2130

Cited by 68 publications

(46 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…16 It has been established that microporous zeolite crystals can be treated (leaching and/or steaming) to generate mesopores that greatly enhance accessibility and thereby catalytic activity and stability. [17][18][19][20][21] A case in point are zeolite Y (FAU) and mordenite (MOR). For FAU detailed studies both on the channel 17 and surface structure 18 and on the mesoporosity 19,20 have been carried out using high-resolution TEM.…”

Section: Resultsmentioning

confidence: 99%

Three-Dimensional Transmission Electron Microscopy: A Novel Imaging and Characterization Technique with Nanometer Scale Resolution for Materials Science

et al. 2000

View full text Add to dashboard Cite

Three-dimensional transmission electron microscopy (3D-TEM), effectuated by multiple imaging of a sample combined with image analysis, offers a new approach in materials science to obtain 3D information of complex solid materials. Here we report first-of-its-kind results that have been obtained with zeolite materials. Virtual cross-sections and volume rendering of the 3D reconstruction of a metal/zeolite crystal (Ag/NaY) give unequivocal information on the location of the silver particles (10-40 nm in diameter). Virtual cross-sections of the 3D reconstruction of an acid-leached mordenite show the three-dimensional mesoporous channel system (3-20 nm in diameter) with a clarity and definition not seen before.Nano-structured inorganic materials, such as solid catalysts, 1 photonic crystals, 2 and electronic devices, 3 are of growing importance in various fields. To gain precision in synthesis and assembly of solids, knowledge of their three-dimensional (3D) structure is required. Electron microscopy is the only technique available to obtain structural information on these types of materials at nanometer scale resolution. However, scanning electron microscopy (SEM) provides surface information with limited information about the internal structure, whereas transmission electron microscopy (TEM) provides only 2D projections of the solid structure. Here we show that 3D-TEM offers a new approach in materials science to obtain 3D information, at nanometer scale resolution, of complex solid materials. 3D-TEM, with its high potential as a unique tool to study biological structures, has rapidly developed during the past few years, which resulted in a first international workshop dedicated to the technique in 1997. 4 Since then, a first generation of automated 3D-TEM data collection systems has become available to the scientific community to study macromolecular structures 5-7 as well as large cellular structures and organelles. 8 So far, it was not recognized that 3D-TEM is also for materials science a unique and powerful tool in the investigation of individual samples of inorganic solids several hundred nanometers in size. With 3D-TEM one can study architecture and composition of individual samples with nanometer scale resolution. 3D-TEM complements other techniques generally used in the characterization of materials such as XRD, XPS, and highresolution TEM. In this paper we describe the principles of 3D-TEM followed by two examples using zeolite materials. The first example involves establishing the location of metal particles in a metal-zeolite crystal (Ag/NaY); the second one involves imaging of mesopores in an acid-leached mordenite crystal.Principles of 3D-TEM. With conventional TEM, images are acquired that are, to a first approximation, 2D projections of a 3D object. Electron tomography, 9 here referred to as 3D-TEM, is a technique where a series of 2D projections (scattering contrast) is recorded that is subsequently used to compute a 3D image (3D reconstruction) of the object under investigation. These projections...

show abstract

Section: Resultsmentioning

confidence: 99%

Three-Dimensional Transmission Electron Microscopy: A Novel Imaging and Characterization Technique with Nanometer Scale Resolution for Materials Science

et al. 2000

View full text Add to dashboard Cite

show abstract

“…This post-synthetic route can be diversified into dealumination or desilication depending on the demetallated species such as Al or Si, respectively. In an old strategy, Al species can be leached out from the zeolite framework by steaming with water vapor at 500°C and subsequent washing with liquid acid, where mesopores are formed [16,17]. This is well known procedure for preparation of ultra-stable Y (USY) zeolites that can be used in fluid catalytic cracking (FCC) reaction [7].…”

Section: Post-synthetic Demetallation Of Zeolite Crystalsmentioning

confidence: 99%

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

Somorjai

2014

Catal Lett

View full text Add to dashboard Cite

The research field of hierarchically nanoporous zeolites has been growing at an enormous pace over the past decades. Hierarchically nanoporous zeolites have versatile structural properties such as high surface area and large pore volume that can alleviate diffusional limitations of conventional zeolites with solely microporous framework. In this review, various synthesis strategies to hierarchically nanoporous zeolites and their structural advantages in catalytic reactions will be reviewed. In the first part, many novel synthetic approaches for hierarchically nanoporous zeolites such as post-demetallation, softtemplating, hard-templating, and dual-pore-generating surfactant-directed methods will be introduced. In the second part, catalytic applications of hierarchically nanoporous zeolites on various chemical reactions involving isomerization, cracking, alkylation and oxidation will be discussed. The present comprehensive review will provide future opportunities and perspectives on the research of hierarchically nanoporous zeolites including their applications to catalytic reactions.

show abstract

“…In top-down approaches, mesopores are introduced after the zeolite has been synthesized, and it is usually achieved by extracting either Al or Si atoms from the zeolite framework. Common methods for demetallation include steaming [33][34][35][36][37][38][39][40], acid-leaching [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] and base treatment [47,48]. In bottom-up approaches, the mesopores are introduced in the framework during the synthesis.…”

Section: Introductionmentioning

confidence: 99%

One-pot synthesis of nano-crystalline MCM-22

Tempelman

Portilla

Martínez-Armero

et al. 2016

Microporous and Mesoporous Materials

View full text Add to dashboard Cite

Nano-crystalline MCM-22 zeolite was synthesized in a one-pot procedure by the use of an organosilane (dimethyl-octadecyl-(3-trimethoxysilylpropyl)-ammonium chloride, TPOAC) in the zeolite synthesis gel. This crystal growth inhibition procedure introduced mesopores in the MCM-22 crystallites. The lower mechanical stability of the nano-crystalline MCM-22 zeolite compared with bulk MCM-22 can be countered to some extent by pillaring. The increased external surface of the microporous zeolite domains resulted in increased accessibility of the Brønsted acid sites, as followed from the better performance in liquidphase benzene alkylation with propylene as compared with bulk MCM-22. The increased accessibility of the internal acid sites in Mo-loaded hierarchical MCM-22 was also evident from the improved benzene selectivity during methane aromatization. Silylation of hierarchical Mo/MCM-22 was detrimental for the catalytic performance in MDA. The nano-crystalline MCM-22 has physico-chemical and catalytic properties intermediate between those of MCM-22 and ITQ-2 with the benefit over ITQ-2 that it can be synthesized in a single step.

show abstract

Structure Analysis of the Mesopore in Dealuminated Zeolite Y by High Resolution TEM Observation with Slow Scan CCD Camera

Cited by 68 publications

References 5 publications

Three-Dimensional Transmission Electron Microscopy: A Novel Imaging and Characterization Technique with Nanometer Scale Resolution for Materials Science

Three-Dimensional Transmission Electron Microscopy: A Novel Imaging and Characterization Technique with Nanometer Scale Resolution for Materials Science

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

One-pot synthesis of nano-crystalline MCM-22

Contact Info

Product

Resources

About