Insights into Coke Formation and Removal under Operating Conditions with a Quantum Nanoreactor Approach
- 23 September 2021
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry Letters
- Vol. 12 (39), 9413-9421
- https://doi.org/10.1021/acs.jpclett.1c02892
Abstract
The in situ formation and removal of coke is a critical problem in heterogeneous catalysis, but its mechanism is not well understood. This work investigates the mechanism of carbon deposition and hydrogenation on an Fe cluster under high-temperature conditions with the density functional tight-binding (DFTB) based nanoreactor molecular dynamics (NMD) method. Our study shows that successive formation of carbon chains, rings, and fused rings occurred during the carbon deposition on Fe clusters. Hydrogenation of activated carbon happens through direct C–H coupling, while the hydrogenation of graphitic carbon involves hydrogenation of the edge carbon, ring-opening reaction, and dealkylation reaction. The main function of the Fe catalyst is to provide the active sites for H2 dissociation and dissociated H spillover, while its activity toward C–C bond breaking is limited. These results highlight the role of the DFTB-NMD method as an effective tool to investigate reaction mechanisms under operating conditions in heterogeneous catalysis.Funding Information
- National Natural Science Foundation of China (21972157, 21972160)
- Chinese Academy of Sciences (YSBR-005, ZDBS-LY-7007)
- Shell Global Solutions International B.V.
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