Formation of Environmentally Persistent Free Radicals (EPFRs) on the Phenol-Dosed α‑Fe 2 O 3 (0001) Surface
2021
academicJournal
Zugriff:
Environmentally persistent free radicals (EPFRs) are a class of toxic air pollutants that are found to form by the chemisorption of substituted aromatic molecules on the surface of metal oxides. In this study, we employ X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) to perform a temperature-dependent study of phenol adsorption on α-Fe 2 O 3 (0001) to probe the radical formation mechanism by monitoring changes in the electronic structure of both the adsorbed phenol and metal oxide substrate. Upon dosing at room temperature, new phenol-derived electronic states have been clearly observed in the UPS spectrum at saturation coverage. However, upon dosing at high temperature (>200 °C), both photoemission techniques have shown distinctive features that strongly suggest electron transfer from adsorbed phenol to Fe 2 O 3 surface atoms and consequent formation of a surface radical. Consistent with the experiment, DFT calculations show that phenoxyl adsorption on the iron oxide surface at RT leads to a minor charge transfer to the adsorbed molecule. The experimental findings at high temperatures agree well with the EPFRs’ proposed formation mechanism and can guide future experimental and computational studies.
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Formation of Environmentally Persistent Free Radicals (EPFRs) on the Phenol-Dosed α‑Fe 2 O 3 (0001) Surface
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Autor/in / Beteiligte Person: | N. I. Sakr (11520758) ; Orhan Kizilkaya (1625320) ; Sierra F. Carlson (11520761) ; Simon Chan (11520764) ; Reuben A. Oumnov (11520767) ; Jaqueline Catano (11520770) ; Richard L. Kurtz (1625314) ; Randall W. Hall (2511007) ; E. D. Poliakoff (1625305) ; Phillip T. Sprunger (1912549) |
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Veröffentlichung: | 2021 |
Medientyp: | academicJournal |
DOI: | 10.1021/acs.jpcc.1c04298.s001 |
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