Structure and Reactivity of the Mo/ZSM-5 Dehydroaromatization Catalyst: An Operando Computational Study

Guanna Li, Ina Vollmer, Chong Liu, Jorge Gascon, Evgeny A. Pidko

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Mo/ZSM-5 is one of the most studied and efficient catalysts for the dehydroaromatization of methane (MDA), but the mechanism of its operation remains controversial. Here, we combine an ab initio thermodynamic analysis with a comprehensive mechanistic density functional theory study to address Mo-speciation in the zeolite and identify the active sites under the reaction conditions. We show that the exposure of Mo/ZSM-5 to the MDA conditions yields a range of reduced sites including mono- and binuclear Mo-oxo and Mo-carbide complexes. These sites can catalyze the MDA reaction via two alternative reaction channels, namely, the C-C coupling (ethylene) and the hydrocarbon-pool propagation mechanisms. Our calculations point toward the binuclear Mo-carbide species operating through the hydrocarbon-pool mechanism to be the most catalytically potent species. Although all other Mo sites in the activated catalyst can promote C-H activation in methane, they fail to provide a successful path to the desirable low-molecular-weight products.
Original languageEnglish (US)
Pages (from-to)8731-8737
Number of pages7
JournalACS Catalysis
Volume9
Issue number9
DOIs
StatePublished - Aug 9 2019

Fingerprint Dive into the research topics of 'Structure and Reactivity of the Mo/ZSM-5 Dehydroaromatization Catalyst: An Operando Computational Study'. Together they form a unique fingerprint.

Cite this