Fischer Tropsch elementary steps on Fe(100)

D. Curulla Ferre, J.W. Niemantsverdriet

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Abstract

Fischer Tropsch is studied using density functional calculations and microkinetic modeling. Elementary steps on Fe(100) are presented in the paper. Particular interest will be focus on the influence of additives (S and K) on CO dissociation and on the hydrogenation of surface C to methane (on clean and S-modified surface). Calculations show that the activation energy of CO dissociation on Fe(100) increases along the series K-modified <clean <S-modified. However, changes on the activation energy are not significantly important. The observation that K-modified Fe(100) can dissociate more CO than the clean surface is explained after studying the interactions of surface oxygen and potassium. Methane formation is also investigated on clean and S-precovered Fe(100). DFT calculations show that methanation energy profile is not significantly influenced by sulfur. However, kinetic modeling shows that there is indeed a considerable influence on the rate of methanation. Furthermore, DFT calculations as well as kinetic modeling suggest that neither CH2 nor CH3 are important in the methanation mechanism and it may be likely that they do not participate in the Fischer Tropsch mechanism(s) on iron catalysts, against the hypothesis established in the alkyl or alkenyl mechanisms.
Original languageEnglish
Title of host publicationProceedings of the 234th ACS National Meeting, 19-23 August 2007, Boston, MA, United States
Place of PublicationWashington, D. C
PublisherAmerican Chemical Society
PagesCATL-010
Publication statusPublished - 2007
Event234th ACS National Meeting - Boston, United States
Duration: 19 Aug 200723 Aug 2007

Conference

Conference234th ACS National Meeting
CountryUnited States
CityBoston
Period19/08/0723/08/07

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Curulla Ferre, D., & Niemantsverdriet, J. W. (2007). Fischer Tropsch elementary steps on Fe(100). In Proceedings of the 234th ACS National Meeting, 19-23 August 2007, Boston, MA, United States (pp. CATL-010). Washington, D. C: American Chemical Society.