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Activating the FeS (001) surface for CO2 adsorption and reduction through the formation of sulfur vacancies: a DFT-D3 study

Dzade, Nelson Y. and de Leeuw, Nora H. 2021. Activating the FeS (001) surface for CO2 adsorption and reduction through the formation of sulfur vacancies: a DFT-D3 study. Catalysts 11 (1) , 127. 10.3390/catal11010127

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Abstract

As a promising material for heterogeneous catalytic applications, layered iron (II) monosulfide (FeS) contains active edges and an inert basal (001) plane. Activating the basal (001) plane could improve the catalytic performance of the FeS material towards CO2 activation and reduction reactions. Herein, we report dispersion-corrected density functional theory (DFT-D3) calculations of the adsorption of CO2 and the elementary steps involved in its reduction through the reverse water-gas shift reaction on a defective FeS (001) surface containing sulfur vacancies. The exposed Fe sites resulting from the creation of sulfur vacancies are shown to act as highly active sites for CO2 activation and reduction. Based on the calculated adsorption energies, we show that the CO2 molecules will outcompete H2O and H2 molecules for the exposed active Fe sites if all three molecules are present on or near the surface. The CO2 molecule is found to weakly physisorb (−0.20 eV) compared to the sulfur-deficient (001) surface where it adsorbs much strongly, releasing adsorption energy of −1.78 and −1.83 eV at the defective FeS (001) surface containing a single and double sulfur vacancy, respectively. The CO2 molecule gained significant charge from the interacting surface Fe ions at the defective surface upon adsorption, which resulted in activation of the C–O bonds confirmed via vibrational frequency analyses. The reaction and activation energy barriers of the elementary steps involved in the CO2 hydrogenation reactions to form CO and H2O species are also unraveled.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Chemistry
Additional Information: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Publisher: MDPI
ISSN: 2073-4344
Funders: EPSRC and the Netherlands Research Council NWO
Date of First Compliant Deposit: 18 January 2021
Date of Acceptance: 12 January 2021
Last Modified: 20 Jan 2021 10:15
URI: http://orca.cardiff.ac.uk/id/eprint/137764

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