Monitoring the methanol conversion process in H-ZSM-5 using synchrotron X-ray powder diffraction-mass spectrometry

Journal Article · Mon Sep 03 00:00:00 EDT 2018 · Journal of Catalysis

DOI:https://doi.org/10.1016/j.jcat.2018.06.027· OSTI ID:1582579

Lo, Benedict T W. ^[1]; Ye, Lin ^[1]; Murray, Claire A. ^[2]; Tang, Chiu ^[3]; Mei, Donghai  ^[4]; Tsang, S C Edman ^[1]

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1. Oxford University
2. Diamond Light Source, Harwell Science and Innovation, UK
3. Diamond Light Source, Ltd.
4. BATTELLE (PACIFIC NW LAB)

By monitoring the catalytic conversion of methanol using operando synchrotron powder X-ray diffraction (SXRD) and structure refinement, in combination with theoretical calculations, we demonstrate for the first time, that the concerted associative mechanism is responsible for dimethyl ether production via an activated protonated methanol intermediate species over H-ZSM-5 in an early stage of reaction at 200 °C. The minor contribution from the dissociative mechanism of the adsorbed methoxy intermediate species at Brønsted acid sites, renders their accumulation during the late stage of reaction, which leads to a build-up of the ‘hydrocarbon pool’ and eventually to ‘carbon’ through the formation of C-C bonds.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1582579
• Report Number(s): PNNL-SA-123879
• Journal Information: Journal of Catalysis, Vol. 365
• Country of Publication: United States
• Language: English