نتایج جستجو برای: 5 zeolite
تعداد نتایج: 1223307 فیلتر نتایج به سال:
Visualizing proton-transfer processes at the nanoscale is essential for understanding the reactivity of zeolite-based catalyst materials. In this work, the Brønsted-acid-catalyzed oligomerization of styrene derivatives was used for the first time as a single molecule probe reaction to study the reactivity of individual zeolite H-ZSM-5 crystals in different zeolite framework, reactant and solven...
Title of Document: SYNTHESIS OF ZEOLITE@MOF NANOPOROUS COMPOSITES AS BIFUNCTIONAL CATALYSTS Guanghui Zhu, Master of Science, 2014 Directed By: Professor, Dr. Dongxia Liu, Department of Chemical and Biomolecular Engineering And Professor, Dr. Kyu Yong Choi, Department of Chemical and Biomolecular Engineering As nanoporous materials, zeolite and metal organic framework (MOF) share common characte...
The Brønsted acid-catalyzed oligomerization of 4-fluorostyrene has been studied on a series of H-ZSM-5 zeolite powders, steamed under different conditions, with a combination of UV-Vis micro-spectroscopy and Scanning Transmission X-ray Microscopy (STXM). UV-Vis micro-spectroscopy and STXM have been used to monitor the relative formation of cyclic and linear dimeric carbocations as a function of...
Zeolite micropattern created from structurally similar hydrophobic Sil-1 and hydrophilic ZSM-5 zeolites, and tested for the immobilization of fluorescein isothiocyanate conjugate bovine serum albumin (BSA-FITC), biotin conjugate bovine serum albumin (Biotin-BSA), Hochest 33342 and rhodamine conjugate αbungatoxin, were preferentially deposited onto hydrophobic ZSM-5 patterns regardless of the pa...
Irradiation of biphenyl encapsulated in the cavities of a NaZSM-5 zeolite framework has been reported to result in the formation of an extremely long-lived radical cation. Here, we show that such zeolite encapsulated radical cations can act as irreversible one-electron oxidants for simple alkenes and dienes, in a solid-state analogue to solution-phase cosensitization. Compared to the well-known...
We report a method to synthesize hollow ZSM-5 single crystals of a size below 100 nm that could function as nanoreactors with access through the zeolite micropores only. In the first step, ZSM-5 is synthesized with the respective crystal size. In the second, the zeolite is base leached and acid washed under mild conditions.
Following the synthesis of aligned single-wall carbon nanotubes in the channels of AlPO4-5 zeolite single crystals, we present the first X-ray diffraction and diffuse scattering results. They can be analysed in terms of a partial filling of the zeolite channels by nanotubes with diameter around 4Å. The possible selection of only one type of nanotube during the synthesis, due to the constraints ...
Optimizing the number, distribution, and accessibility of Brønsted acid sites in zeolite-based catalysts is of a paramount importance to further improve their catalytic performance. However, it remains challenging to measure real-time changes in reactivity of single zeolite catalyst particles by ensemble-averaging characterization methods. In this work, a detailed 3D single molecule, single tur...
Novel nanocomposites consisting of a water-soluble acrylamide-based photopolymer and colloidal zeolite nanoparticles of zeolite Beta and zeolite A were prepared. The interactions between the photopolymer components and zeolite nanoparticles in the photopolymerizable nanocomposites were characterized for the first time by (13)C nuclear magnetic resonance and visible spectroscopy. It was found th...
Fluid catalytic cracking (FCC) is a major process in oil refineries to produce gasoline and base chemicals from crude oil fractions. The spatial distribution and acidity of zeolite aggregates embedded within the 50-150 μm-sized FCC spheres heavily influence their catalytic performance. Single-molecule fluorescence-based imaging methods, namely nanometer accuracy by stochastic chemical reactions...
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