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Activation and dissociation of CO2 on the (001), (011), and (111) surfaces of mackinawite (FeS): a dispersion-corrected DFT study

Dzade, Nelson Y., Roldan Martinez, Alberto and de Leeuw, Nora H. 2015. Activation and dissociation of CO2 on the (001), (011), and (111) surfaces of mackinawite (FeS): a dispersion-corrected DFT study. Journal of Chemical Physics 143 (9) , 94703. 10.1063/1.4929470

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Abstract

Iron sulfide minerals, including mackinawite (FeS), are relevant in origin of life theories, due to their potential catalytic activity towards the reduction and conversion of carbon dioxide (CO2) to organic molecules, which may be applicable to the production of liquid fuels and commodity chemicals. However, the fundamental understanding of CO2 adsorption, activation, and dissociation on FeS surfaces remains incomplete. Here, we have used density functional theory calculations, corrected for long-range dispersion interactions (DFT-D2), to explore various adsorption sites and configurations for CO2 on the low-index mackinawite (001), (110), and (111) surfaces. We found that the CO2 molecule physisorbs weakly on the energetically most stable (001) surface but adsorbs relatively strongly on the (011) and (111) FeS surfaces, preferentially at Fe sites. The adsorption of the CO2 on the (011) and (111) surfaces is shown to be characterized by significant charge transfer from surface Fe species to the CO2 molecule, which causes a large structural transformation in the molecule (i.e., forming a negatively charged bent CO2−δ species, with weaker C—O confirmed via vibrational frequency analyses). We have also analyzed the pathways for CO2 reduction to CO and O on the mackinawite (011) and (111) surfaces. CO2 dissociation is calculated to be slightly endothermic relative to the associatively adsorbed states, with relatively large activation energy barriers of 1.25 eV and 0.72 eV on the (011) and (111) surfaces, respectively.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Chemistry
Subjects: Q Science > QD Chemistry
Additional Information: PDF uploaded in accordance with publisher's policies at http://www.sherpa.ac.uk/romeo/issn/0021-9606/ (accessed 2.6.16).
Publisher: American Institute of Physics
ISSN: 0021-9606
Date of First Compliant Deposit: 2 June 2016
Date of Acceptance: 12 August 2015
Last Modified: 19 Oct 2019 15:32
URI: http://orca-mwe.cf.ac.uk/id/eprint/86959

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