Microcalorimetry on Cu-MCM-22 Reveals Structure-Activity Relationships for the Methane-to-Methanol Reaction
Kvande, Karoline; Mawanga, Moses; Prodinger, Sebastian; Solemsli, Bjørn Gading; Yang, Jia; Olsbye, Unni; Beato, Pablo; Blekkan, Edd Anders; Svelle, Stian
Peer reviewed, Journal article
Submitted version
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https://hdl.handle.net/11250/3107003Utgivelsesdato
2023Metadata
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Industrial & Engineering Chemistry Research. 2023, 62 (28), 10939-10950. 10.1021/acs.iecr.3c00988Sammendrag
With a stepwise mechanism for direct methane activation to methanol (MTM) over Cu-zeolites, it is possible to produce methanol with high selectivity. With this study, we apply adsorption/desorption experiments with n-propylamine, NH3, and CH4 as powerful techniques to learn more about the acidity and nature of the Cu-sites within a hitherto untested material for MTM, namely, MCM-22. The Cu-exchanged zeolites have a moderate performance in MTM (∼0.10 molMeOH/molCu), and upon comparing to the activity of other zeolite frameworks, we use the results found for MCM-22 to search for structure–activity relationships. We show with CO-adsorption FT-IR spectroscopy experiments that there is more than one distinct Cu-site within MCM-22, where one of which is likely linked with inactive Cu species. NH3 adsorption/desorption experiments disclose that the Brønsted acid sites before Cu exchange are few and heterogeneous in strength, leading to a low number of C–H-activating Cu-oxo species.