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Title
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A combined experimental and computational approach to understanding CdS pigment oxidation in a renowned early 20th century painting
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Author
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Abstract
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| Cadmium sulfide (CdS)-based yellow pigments have been used in a number of early 20th century artworks, including The Scream series painted by Edvard Munch. Some of these unique paintings are threatened by the discoloration of these CdS-based yellow oil paints because of the oxidation of the original sulfides to sulfates. The experimental data obtained here prove that moisture and cadmium chloride compounds play a key role in promoting such oxidation. To clarify how these two factors effectively prompt the process, we studied the band alignment between CdS, CdCl2, and Cd-(OH)Cl as well as the radicals center dot OH and H3O center dot by density functional theory (DFT) methods. Our results show that a stack of several layers of Cd-(OH)Cl creates a pocket of positive holes at the Cl-terminated surface and a pocket of electrons at the OH-terminated surface by leading in a difference in ionization energy at both surfaces. The resulting band alignment indicates that Cd-(OH)Cl can indeed play the role of an oxidative catalyst for CdS in a moist environment, thus providing an explanation for the experimental evidence. |
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Language
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English
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Source (journal)
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Chemistry of materials / American Chemical Society. - Washington, D.C., 1989, currens
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Publication
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Washington, D.C.
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2023
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ISSN
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0897-4756
[print]
1520-5002
[online]
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DOI
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10.1021/ACS.CHEMMATER.3C01470
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Volume/pages
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35
:24
(2023)
, p. 10403-10415
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ISI
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001133000900001
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Full text (Publisher's DOI)
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Full text (open access)
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Full text (publisher's version - intranet only)
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