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Title: Highly dispersed SiOx/Al2O3 catalysts illuminate the reactivity of isolated silanol sites

The reaction of γ-alumina with tetraethylorthosilicate (TEOS) vapor at low temperatures selectively yields monomeric SiOx species on the alumina surface. These isolated (-AlO)3Si(OH) sites are characterized by PXRD, XPS, DRIFTS of adsorbed NH3, CO, and pyridine, and 29Si and 27Al DNP-enhanced solid-state NMR spectroscopy. The formation of isolated sites suggests that TEOS reacts preferentially at strong Lewis acid sites on the γ-Al2O3 surface, functionalizing the surface with “mild” Brønsted acid sites. As a result, for liquid-phase catalytic cyclohexanol dehydration, these SiOx sites exhibit up to 3.5-fold higher specific activity than the parent alumina with identical selectivity.
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [1] ;  [1] ;  [1]
  1. Northwestern Univ., Evanston, IL (United States)
  2. Iowa State Univ., Ames, IA (United States)
Publication Date:
OSTI Identifier:
1227425
Report Number(s):
IS-J--8828
Journal ID: ISSN 1433-7851
Grant/Contract Number:
CHE1213235; CHE0923236; AC02-06CH11357; FG02-03ER15457; DMR1121262; EEC0118025/003; SC0001329; AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Angewandte Chemie (International Edition)
Additional Journal Information:
Journal Name: Angewandte Chemie (International Edition); Journal Volume: 54; Journal Issue: 45; Journal ID: ISSN 1433-7851
Publisher:
Wiley
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY