There are no files associated with this item.
Full metadata record
DC Field | Value | Language |
---|---|---|
dc.citation.endPage | 23362 | - |
dc.citation.number | 47 | - |
dc.citation.startPage | 23354 | - |
dc.citation.title | JOURNAL OF PHYSICAL CHEMISTRY C | - |
dc.citation.volume | 115 | - |
dc.contributor.author | Hu, Jian Zhi | - |
dc.contributor.author | Kwak, Jahun | - |
dc.contributor.author | Wang, Yong | - |
dc.contributor.author | Hu, Mary Y. | - |
dc.contributor.author | Turcu, Romulus V. | - |
dc.contributor.author | Peden, Charles H. F. | - |
dc.date.accessioned | 2023-12-22T05:39:08Z | - |
dc.date.available | 2023-12-22T05:39:08Z | - |
dc.date.created | 2015-07-21 | - |
dc.date.issued | 2011-12 | - |
dc.description.abstract | The acidic sites in dispersed tungsten oxide supported on SBA-15 mesoporous silica were investigated using a combination of pyridine titration, both fast- and slow-MAS N-15 NMR, static H-2 NMR, and quantum chemistry calculations. It is found that the bridging acidic -OH groups in surface-adsorbed tungsten dimers or multimers (i.e., W-OH-W) are the Bronsted acid sites. The unusually strong acidity of these Bronsted acid sites is confirmed by quantum chemistry calculations. In contrast, terminal W-OH sites are very stable and only weakly acidic as are terminal Si-OH sites. Furthermore, molecular interactions between pyridine molecules and the Bronsted and terminal W-OH sites for dispersed tungsten oxide species are strong. This results in restricted molecular motion for the interacting pyridine molecules even at room temperature, that is, a reorientation mainly about the molecular C-2 symmetry axis. The restricted reorientation results in efficient H-1-N-15 cross-polarization, making it possible to estimate the relative ratio of the Bronsted to the weakly acidic terminal W-OH sites in the catalyst using the slow-MAS H-1-N-15 CP PASS method | - |
dc.identifier.bibliographicCitation | JOURNAL OF PHYSICAL CHEMISTRY C, v.115, no.47, pp.23354 - 23362 | - |
dc.identifier.doi | 10.1021/jp203813f | - |
dc.identifier.issn | 1932-7447 | - |
dc.identifier.scopusid | 2-s2.0-82155170629 | - |
dc.identifier.uri | https://scholarworks.unist.ac.kr/handle/201301/12297 | - |
dc.identifier.url | http://pubs.acs.org/doi/abs/10.1021/jp203813f | - |
dc.identifier.wosid | 000297195200015 | - |
dc.language | 영어 | - |
dc.publisher | AMER CHEMICAL SOC | - |
dc.title.alternative | Characterizing Surface Acidic Sites in Mesoporous-Silica-Supported Tungsten Oxide Catalysts Using Solid-State NMR and Quantum Chemistry Calculations | - |
dc.title | Characterizing Surface Acidic Sites in Mesoporous-Silica-Supported Tungsten Oxide Catalysts Using Solid-State NMR and Quantum Chemistry Calculations | - |
dc.type | Article | - |
dc.description.journalRegisteredClass | scie | - |
dc.description.journalRegisteredClass | scopus | - |
dc.subject.keywordPlus | CHEMICAL-SHIFT-ANISOTROPY | - |
dc.subject.keywordPlus | TENSOR PRINCIPAL VALUES | - |
dc.subject.keywordPlus | ANGLE TURNING EXPERIMENT | - |
dc.subject.keywordPlus | MAGIC-ANGLE | - |
dc.subject.keywordPlus | N-15 NMR | - |
dc.subject.keywordPlus | SKELETAL ISOMERIZATION | - |
dc.subject.keywordPlus | SPINNING NMR | - |
dc.subject.keywordPlus | ACTIVATED CARBON | - |
dc.subject.keywordPlus | POWDER PATTERNS | - |
dc.subject.keywordPlus | GAMMA-ALUMINA | - |
Items in Repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Tel : 052-217-1404 / Email : scholarworks@unist.ac.kr
Copyright (c) 2023 by UNIST LIBRARY. All rights reserved.
ScholarWorks@UNIST was established as an OAK Project for the National Library of Korea.