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Dynamic modification of pore opening of SAPO-34 by adsorbed surface methoxy species during induction of catalytic methanol-to-olefins reactions

DOI: 10.1016/j.apcatb.2018.05.090 DOI Help

Authors: B. T. W. Lo (University of Oxford) , L. Ye (University of Oxford) , G. G. Z. Chang (University of Oxford) , K. Purchase (University of Oxford) , Sarah Day (Diamond Light Source) , C. C. Tang (Diamond Light Source) , D. Mei (Physical and Computational Sciences Directorate & Institute for Integrated Catalysis) , S. C. E. Tsang (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Applied Catalysis B: Environmental

State: Published (Approved)
Published: May 2018

Abstract: Here, we report that the 8-membered ring pore opening of SAPO-34 zeolite can be significantly modified by an adsorbed surface methoxy species (SMS) during the induction period of the catalytic methanol-to-olefins process, which offers molecular sieving properties. It is due to the physical obstruction caused by the surface methoxy species, which also modifies the adsorption properties of other hydrocarbons. Synchrotron X-ray powder diffraction and Rietveld refinement reveal that the SMS is dynamically created from methanol dehydration on a Brønsted acid site near the narrow pore windows. Thus, industrially desirable lower olefins such as ethylene and propylene can be favourably made at the expense of higher olefins. The crystal structures and fundamental understanding in altering the olefin selectivity during induction may allow rational optimisation in catalytic performance under complex fluidised conditions. This work offers additional but alternative insights to the ‘dual cycle’ mechanistic study of the catalytic methanol-to-olefins process.

Journal Keywords: Methanol conversion; SAPO-34 zeolite; synchrotron X-ray powder diffraction; product distribution; surface methoxy surface

Subject Areas: Chemistry, Materials, Energy

Instruments: I11-High Resolution Powder Diffraction

Added On: 06/06/2018 09:04

Discipline Tags:

Zeolites Bioenergy Earth Sciences & Environment Sustainable Energy Systems Energy Climate Change Physical Chemistry Catalysis Chemistry Materials Science

Technical Tags:

Diffraction X-ray Powder Diffraction