Highly Dispersed SiOx/Al2O3 Catalysts Illuminate the Reactivity of Isolated Silanol Sites

Aidan R. Mouat; Cassandra George; Takeshi Kobayashi; Marek Pruski; Richard P. Van Duyne; Tobin J. Marks; Peter C. Stair

doi:10.1002/anie.201505452

Highly Dispersed SiO_x/Al₂O₃ Catalysts Illuminate the Reactivity of Isolated Silanol Sites

Aidan R. Mouat, Cassandra George, Takeshi Kobayashi, Marek Pruski, Richard P. Van Duyne, Tobin J. Marks, Peter C. Stair

Northwestern University

Research output: Contribution to journal › Article

45 Citations (Scopus)

Abstract

The reaction of γ-alumina with tetraethylorthosilicate (TEOS) vapor at low temperatures selectively yields monomeric SiO_x 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. For liquid-phase catalytic cyclohexanol dehydration, these SiO_x sites exhibit up to 3.5-fold higher specific activity than the parent alumina with identical selectivity.

Original language	English
Pages (from-to)	13346-13351
Number of pages	6
Journal	Angewandte Chemie - International Edition
Volume	54
Issue number	45
DOIs	https://doi.org/10.1002/anie.201505452
Publication status	Published - Nov 1 2015

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Keywords

alcohol dehydration
atomic layer deposition
heterogeneous catalysis
silica-alumina
solid acid

ASJC Scopus subject areas

Catalysis
Chemistry(all)

Cite this

Mouat, A. R., George, C., Kobayashi, T., Pruski, M., Van Duyne, R. P., Marks, T. J., & Stair, P. C. (2015). Highly Dispersed SiO_x/Al₂O₃ Catalysts Illuminate the Reactivity of Isolated Silanol Sites. Angewandte Chemie - International Edition, 54(45), 13346-13351. https://doi.org/10.1002/anie.201505452

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title = "Highly Dispersed SiOx/Al2O3 Catalysts Illuminate the Reactivity of Isolated Silanol Sites",

abstract = "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{"} Br{\o}nsted acid sites. 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.",

keywords = "alcohol dehydration, atomic layer deposition, heterogeneous catalysis, silica-alumina, solid acid",

author = "Mouat, {Aidan R.} and Cassandra George and Takeshi Kobayashi and Marek Pruski and {Van Duyne}, {Richard P.} and Marks, {Tobin J.} and Stair, {Peter C.}",

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AU - Mouat, Aidan R.

AU - George, Cassandra

AU - Kobayashi, Takeshi

AU - Pruski, Marek

AU - Van Duyne, Richard P.

AU - Marks, Tobin J.

AU - Stair, Peter C.

PY - 2015/11/1

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N2 - 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. 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.

AB - 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. 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.

KW - alcohol dehydration

KW - atomic layer deposition

KW - heterogeneous catalysis

KW - silica-alumina

KW - solid acid

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Access to Document

10.1002/anie.201505452