The application of inelastic neutron scattering to investigate iron-based Fischer-Tropsch to olefins catalysis

Davidson, A. L., Gibson, E. K. , Cibin, G., van Rensburg, H., Parker, S. F., Webb, P. B. and Lennon, D. (2020) The application of inelastic neutron scattering to investigate iron-based Fischer-Tropsch to olefins catalysis. Journal of Catalysis, 392, pp. 197-208. (doi: 10.1016/j.jcat.2020.09.025)

Abstract

The technique of inelastic neutron scattering (INS) is used to investigate how hydrogen is partitioned within a series of Na and S promoted iron-based Fischer-Tropsch-to-olefin catalysts. Two reaction test regimes are examined. First, reaction testing at elevated temperature and pressure demonstrate how Na/S additions enhance short chain olefin selectivity and reduce methane formation under industrially relevant reaction conditions. For a fixed level of Na incorporation (2000 ppm), sulfur concentrations of ≤ 100 ppm result in only a modest improvement in olefin selectivity. However, for sulfur values of ≥ 100 ppm there is a noticeable and systematic increase in C2-C4 olefin selectivity; rising from ∼30.0 % to 35.2% at 250 ppm. Second, using ambient pressure CO hydrogenation as a test reaction in INS and micro-reactor configurations, catalyst samples are further analysed by TPR, TPO, XRD and S K-edge XANES. INS shows the formation of a hydrocarbonaceous overlayer to be significantly attenuated by the presence of the promoters, with increasing S levels significantly reducing the intensity of the sp2 and sp3 hybridised ν(C-H) modes of the overlayer, albeit to differing degrees. A probable role for how this combination of promoters is perturbing the form of the hydrocarbonaceous overlayer to subsequently moderate the product distribution is considered.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lennon, Professor David and Gibson, Dr Emma and Davidson, Dr Alisha
• Authors: Davidson, A. L., Gibson, E. K., Cibin, G., van Rensburg, H., Parker, S. F., Webb, P. B., and Lennon, D.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Catalysis
• Publisher: Elsevier
• ISSN: 0021-9517
• ISSN (Online): 1090-2694
• Published Online: 08 October 2020
• Copyright Holders: Copyright © 2020 Elsevier Inc.
• First Published: First published in Journal of Catalysis 392:197-208
• Publisher Policy: Reproduced under a Creative Commons licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
190262		EPSRC Doctoral Training Grant 2010-14	Mary Beth Kneafsey	Engineering and Physical Sciences Research Council (EPSRC)	EP/P505534/1	Research and Innovation Services