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Modeling phase formation on catalyst surfaces: Coke formation and suppression in hydrocarbon environments
  • Peng Wang,
  • Thomas Senftle
Peng Wang
Rice University
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Thomas Senftle
Rice University
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Abstract

We develop a simulation toolset employing density functional theory (DFT) in conjunction with grand canonical Monte Carlo (GCMC) to study coke formation on Fe-based catalysts during propane dehydrogenation (PDH). As expected, pure Fe surfaces develop stable graphitic coke structures and rapidly deactivate. We find that coke formation is markedly less favorable on Fe3C and FeS surfaces. Fe-Al alloys display varying degrees of coke resistance, depending on their composition, suggesting that they can be optimized for coke resistance under PDH conditions. Electronic structure analyses show that both electron-withdrawing effects (on Fe3C and FeS) and electron-donating effects (on Fe-Al alloys) destabilize adsorbed carbon. On the alloy surfaces, a geometric effect also isolates Fe sites and disrupts the formation of graphitic carbon networks. This work demonstrates the utility of GCMC for studying the formation of disordered phases on catalyst surfaces and provides insights for improving the coke resistance of Fe-based PDH catalysts.

Peer review status:ACCEPTED

24 May 2021Submitted to AIChE Journal
31 May 2021Submission Checks Completed
31 May 2021Assigned to Editor
13 Jun 2021Reviewer(s) Assigned
29 Jul 2021Editorial Decision: Revise Major
28 Aug 20211st Revision Received
07 Sep 2021Submission Checks Completed
07 Sep 2021Assigned to Editor
08 Sep 2021Reviewer(s) Assigned
21 Sep 2021Editorial Decision: Accept