Examining the temporal behavior of the hydrocarbonaceous overlayer on an iron based Fischer–Tropsch catalyst. Issue 5 (18th January 2019)

• Record Type: Journal Article
• Authors: Warringham, Robbie; Davidson, Alisha L.; Webb, Paul B.; Tooze, Robert P.; Ewings, Russel A.; Parker, Stewart F.; Lennon, David
• Is Part Of: RSC advances. Volume 9:Issue 5(2019)
• Page Start: 2608
• Page End: 2617
• Publication Date: 2019-01-18
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8ra09731c
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Inelastic neutron scattering is used to examine an un-promoted iron based Fischer–Tropsch synthesis catalyst exposed to ambient pressure CO hydrogenation at 623 K for defined periods of time-on-stream (3, 6, 12 and 24 h). Abstract : In order to examine fundamental processes connected with the use of an unpromoted iron based Fischer–Tropsch synthesis (FTS) catalyst, model studies examining the temporal formation of hydrocarbonaceous species that form over the catalyst are undertaken using a combination of temperature-programmed oxidation, powder X-ray diffraction, Raman scattering, transmission electron microscopy and inelastic neutron scattering (INS). Catalyst samples were exposed to ambient pressure CO hydrogenation at 623 K for defined periods of time-on-stream (3, 6, 12 and 24 h) prior to analysis. INS reveals a progressive retention of hydrogenous species that is associated with the evolution of a hydrocarbonaceous overlayer, as evidenced by the presence of sp 2 and sp 3 hybridized C–H vibrational modes. Correlations between the formation of aliphatic and olefinic/aromatic moieties with post-reaction characterization leads to the proposal of a number of chemical transformations that, collectively, define the conditioning phase of the catalyst under the specified set of reaction conditions. A comparison between the inelastic neutron scattering spectra of the 24 h sample with that of an iron catalyst extracted from a commercial grade Fischer–Tropsch reactor validates the relevance of the experimental approach adopted.