Unraveling Radical and Oxygenate Routes in the Oxidative Dehydrogenation of Propane over Boron Nitride


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Date

2023-04-12

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Oxidative dehydrogenation of propane (ODHP) is an emerging technology to meet the global propylene demand with boron nitride (BN) catalysts likely to play a pivotal role. It is widely accepted that gas-phase chemistry plays a fundamental role in the BN-catalyzed ODHP. However, the mechanism remains elusive because short-lived intermediates are difficult to capture. We detect short-lived free radicals (CH3 center dot, C3H5 center dot) and reactive oxygenates, C2-4 ketenes and C2-3 enols, in ODHP over BN by operando synchrotron photoelectron photoion coincidence spectroscopy. In addition to a surface-catalyzed channel, we identify a gas-phase H-acceptor radical-and H -donor oxygenate-driven route, leading to olefin production. In this route, partially oxidized enols propagate into the gas phase, followed by dehydrogenation (and methylation) to form ketenes and finally yield olefins by decarbonylation. Quantum chemical calculations predict the >BO dangling site to be the source of free radicals in the process. More importantly, the easy desorption of oxygenates from the catalyst surface is key to prevent deep oxidation to CO2.

Publication status

published

Editor

Book title

Volume

145 (14)

Pages / Article No.

7910 - 7917

Publisher

American Chemical Society

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Edition / version

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Organisational unit

03871 - Pérez-Ramírez, Javier / Pérez-Ramírez, Javier check_circle

Notes

Funding

180544 - NCCR Catalysis (phase I) (SNF)

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