Details

Autor(en) / Beteiligte

• Sakr, N. I
• Kizilkaya, Orhan
• Carlson, Sierra F
• Chan, Simon
• Oumnov, Reuben A
• Catano, Jaqueline
• Kurtz, Richard L
• Hall, Randall W
• Poliakoff, E. D
• Sprunger, Phillip T

Titel

Formation of Environmentally Persistent Free Radicals (EPFRs) on the Phenol-Dosed α‑Fe2O3(0001) Surface

Ist Teil von

• Journal of physical chemistry. C, 2021-10, Vol.125 (40), p.21882-21890

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2021

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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-Fe2O3(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 Fe2O3 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.