Direct Correlation between Adsorption Energetics and Nuclear Spin Relaxation in a Liquid-saturated Catalyst Material.
Publication Date
2018-10-05Journal Title
Chemphyschem
ISSN
1439-4235
Publisher
Wiley
Volume
19
Issue
19
Pages
2472-2479
Language
eng
Type
Article
Physical Medium
Print-Electronic
Metadata
Show full item recordCitation
Robinson, N., Robertson, C., Gladden, L., Jenkins, S., & D'Agostino, C. (2018). Direct Correlation between Adsorption Energetics and Nuclear Spin Relaxation in a Liquid-saturated Catalyst Material.. Chemphyschem, 19 (19), 2472-2479. https://doi.org/10.1002/cphc.201800513
Abstract
The ratio of NMR relaxation time constants <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mn>1</mml:mn></mml:msub> <mml:mo>/</mml:mo> <mml:msub><mml:mi>T</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:mrow> </mml:math> provides a non-destructive indication of the relative surface affinities exhibited by adsorbates within liquid-saturated mesoporous catalysts. In the present work we provide supporting evidence for the existence of a quantitative relationship between such measurements and adsorption energetics. As a prototypical example with relevance to green chemical processes we examine and contrast the relaxation characteristics of primary alcohols and cyclohexane within an industrial silica catalyst support. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mn>1</mml:mn></mml:msub> <mml:mo>/</mml:mo> <mml:msub><mml:mi>T</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:mrow> </mml:math> values obtained at intermediate magnetic field strength are in good agreement with DFT adsorption energy calculations performed on single molecules interacting with an idealised silica surface. Our results demonstrate the remarkable ability of this metric to quantify surface affinities within systems of relevance to liquid-phase heterogeneous catalysis, and highlight NMR relaxation as a powerful method for the determination of adsorption phenomena within mesoporous solids.
Sponsorship
Catalysis@Cambridge, BP plc
Identifiers
External DOI: https://doi.org/10.1002/cphc.201800513
This record's URL: https://www.repository.cam.ac.uk/handle/1810/284491
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