Highly Dispersed SiOx/Al2O3 Catalysts Illuminate the Reactivity of Isolated Silanol Sites |
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| Authors: | Aidan R. Mouat Cassandra George Dr. Takeshi Kobayashi Prof. Marek Pruski Prof. Richard P. van Duyne Prof. Tobin J. Marks Prof. Peter C. Stair |
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| Affiliation: | 1. Chemistry Department and the Center for Catalysis and Surface Science, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208 (USA);2. U.S. DOE Ames Laboratory, and Department of Chemistry, Iowa State University, Ames, IA 50011 (USA) |
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| 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” 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. |
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| Keywords: | alcohol dehydration atomic layer deposition heterogeneous catalysis silica‐alumina solid acid |
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