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Initial Carbon−Carbon Bond Formation during the Early Stages of Methane Dehydroaromatization
Author(s) -
Çağlayan Mustafa,
Lucini Paioni Alessandra,
AbouHamad Edy,
Shterk Genrikh,
Pustovarenko Alexey,
Baldus Marc,
Chowdhury Abhishek Dutta,
Gascon Jorge
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202007283
Subject(s) - chemistry , catalysis , methane , acetylene , formate , photochemistry , reaction mechanism , carbon fibers , magic angle spinning , hydrocarbon , chemical engineering , nuclear magnetic resonance spectroscopy , organic chemistry , materials science , composite number , composite material , engineering
Methane dehydroaromatization (MDA) is among the most challenging processes in catalysis science owing to the inherent harsh reaction conditions and fast catalyst deactivation. To improve this process, understanding the mechanism of the initial C−C bond formation is essential. However, consensus about the actual reaction mechanism is still to be achieved. In this work, using advanced magic‐angle spinning (MAS) solid‐state NMR spectroscopy, we study in detail the early stages of the reaction over a well‐dispersed Mo/H‐ZSM‐5 catalyst. Simultaneous detection of acetylene (i.e., presumably the direct C−C bond‐forming product from methane), methylidene, allenes, acetal, and surface‐formate species, along with the typical olefinic/aromatic species, allow us to conclude the existence of at least two independent C−H activation pathways. Moreover, this study emphasizes the significance of mobility‐dependent host–guest chemistry between an inorganic zeolite and its trapped organic species during heterogeneous catalysis.