Perspectives on the effect of sulfur on the hydrocarbonaceous overlayer on iron Fischer-Tropsch catalysts

Warringham, R., Davidson, A. L., Webb, P. B., Tooze, R. P., Parker, S. F. and Lennon, D. (2020) Perspectives on the effect of sulfur on the hydrocarbonaceous overlayer on iron Fischer-Tropsch catalysts. Catalysis Today, 339, pp. 32-39. (doi: 10.1016/j.cattod.2019.02.035)

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Abstract

Fischer-Tropsch synthesis (FTS) is commonly viewed as an alternative approach to the production of diesel fuels via sources independent of crude oil. The adaptability of the FTS process allows for the selective production of shorter chain C2 to C6 hydrocarbons and has the potential to be a legitimate source of useable chemical feedstocks with high value to the chemical manufacturing industry. Interestingly, although recognised as a poison in most catalytic systems, small amounts of sulfur in iron-based FTS catalysts has been demonstrated to promote catalyst reducibility and activity towards shorter chain hydrocarbons. However, it is not known what impact sulfur has on the formation of hydrocarbonaceous surface species that have been proposed to play a pivotal role in the mediation of reactants during iron FTS. Here we apply ambient pressure CO hydrogenation at 623 K on a selection of sulfur promoted iron FTS catalysts to investigate the effect of sulfur content on hydrocarbonaceous species formation. For the first time, we report the application of inelastic neutron scattering to quantify the presence of hydrocarbonaceous species under the presence of sulfur promotion. In combination with temperature programmed oxidation, X-ray diffraction, and Raman spectroscopy, we observe how low sulfur loadings (<700 ppm) perturb carbon and hydrogen retention levels. The results indicate that the presence and nature of the hydrocarbonaceous overlayer is sensitive to sulfur loading, with the reported loss in catalytic activity at high loadings correlating with the attenuation of hydrocarbonaceous surface species.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Warringham, Mr Robbie and Davidson, Dr Alisha and Lennon, Professor David
Authors: Warringham, R., Davidson, A. L., Webb, P. B., Tooze, R. P., Parker, S. F., and Lennon, D.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Catalysis Today
Publisher:Elsevier
ISSN:0920-5861
ISSN (Online):1873-4308
Published Online:18 February 2019
Copyright Holders:Copyright © 2019 Elsevier B.V.
First Published:First published in Catalysis Today 339:32-39
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
518721Engineering and Physical Sciences Doctoral Training Grant 2009-13Mary GoodmanEngineering and Physical Sciences Research Council (EPSRC)EP/P504937/1VPO VICE PRINCIPAL RESEARCH & ENTERPRISE
554794EPSRC Doctoral Training Grant 2010-14Mary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/P505534/1VPO VICE PRINCIPAL RESEARCH & ENTERPRISE