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Surface and shape modification of mackinawite (FeS) nanocrystals by cysteine adsorption: a first-principles DFT-D2 study

Dzade, Nelson, Roldan Martinez, Alberto and De Leeuw, Nora 2016. Surface and shape modification of mackinawite (FeS) nanocrystals by cysteine adsorption: a first-principles DFT-D2 study. Physical Chemistry Chemical Physics 18 (47) , pp. 32007-32020. 10.1039/C6CP05913A

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Abstract

The control of nanoparticle shape offers promise for improving catalytic activity and selectivity through optimization of the structure of the catalytically active site. Here, we have employed density functional theory calculations with a correction for the long-range interactions (DFT-D2) to investigate the effect of adsorption of the amino acid cysteine on the {001}, {011}, {100}, and {111} surfaces of mackinawite, which are commonly found in FeS nanoparticles. We have calculated the surface energies and adsorption energies for all the surfaces considered, and compared the surface energies of the pure and adsorbed systems. Based on the calculated surface energies, we have simulated the thermodynamic crystal morphology of the pure and cysteine-modified FeS nanoparticles using Wulff's construction. The strength of cysteine adsorption is found to be related to the stability of different surfaces, where it adsorbs most strongly onto the least stable FeS{111} surface via bidentate Fe–S and Fe–N chemical bonds and most weakly onto the most stable FeS{001} surface via hydrogen-bonded interactions; the adsorption energy decreases in the order {111} > {100} > {011} > {001}. We demonstrate that the stronger binding of the cysteine to the {011}, {100}, and {111} surfaces rather than to the {001} facet results in shape modulation of the FeS nanoparticles, with the reactive surfaces more expressed in the thermodynamic crystal morphology compared to the unmodified FeS crystals. Information regarding the structural parameters, electronic structures and vibrational frequency assignments of the cysteine–FeS complexes is also presented.

Item Type: Article
Date Type: Published Online
Status: Published
Schools: Chemistry
Subjects: Q Science > QD Chemistry
Publisher: Royal Society of Chemistry
ISSN: 1463-9076
Date of First Compliant Deposit: 27 January 2017
Date of Acceptance: 22 September 2016
Last Modified: 02 Aug 2019 12:44
URI: http://orca-mwe.cf.ac.uk/id/eprint/97825

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