title: The fast Z-scan method for studying working catalytic reactors with high energy X-ray diffraction: ZSM-5 in the methanol to gasoline process.
abstract: The methanol to gasoline process over the zeolite catalyst ZSM-5 in a lab-sized reactor bed (4 mm diameter) has been studied in operando with high energy synchrotron X-ray diffraction. The fast z-scan method was used, scanning the reactor repeatedly and at speed through the X-ray beam. The X-ray diffraction data were processed using high throughput parametric Rietveld refinement to obtain real structural parameters. The diffraction data show only very subtle changes during the process and this allows us to demonstrate the combination of very large data volumes with parametric Rietveld methods to study weak features of the data. The different possible data treatment methodologies are discussed in detail and their effects on the results obtained are demonstrated. The trends in unit cell volume, zeolite channel occupancy and crystallite strain indicate that more or larger reaction intermediates are present close to the reactor outlet.
authors.affiliation: inGAP Centre for Research Based Innovation and Department of Chemistry, University of Oslo, Postboks 1033, Blindern, Oslo, Norway. david.wragg@smn.uio.no
authors.forename: David S
authors.initials: DS
authors.lastname: Wragg
authors.forename: Francesca L
authors.initials: FL
authors.lastname: Bleken
authors.forename: Matthew G
authors.initials: MG
authors.lastname: O'Brien
authors.forename: Marco
authors.initials: M
authors.lastname: Di Michiel
authors.forename: Helmer
authors.initials: H
authors.lastname: Fjellvåg
authors.forename: Unni
authors.initials: U
authors.lastname: Olsbye
mesh_terms: D002384:Catalysis; D005742:Gasoline; D000432:Methanol / Q000737:chemistry*; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D005742:Gasoline; C570564:ZSM-5 zeolite; D017641:Zeolites; D000432:Methanol