Iron near absorption edge X-ray spectroscopy at aqueous-membrane interfaces

Journal Article · Wed Jan 01 04:00:00 EST 2014 · Physical Chemistry Chemical Physics

DOI:https://doi.org/10.1039/C4CP00657G· OSTI ID:1157659

Wang, Wenjie; Kuzmenko, Ivan; Vaknin, David

Employing synchrotron X-ray scattering, we systematically determine the absorption near-edge spectra (XANES) of iron in its ferrous (Fe2+) and ferric (Fe3+) states both as ions in aqueous solutions and as they bind to form a single layer to anionic templates that consist of carboxyl or phosphate groups at aqueous/vapor interfaces. While the XANES of bulk iron ions show that the electronic state and coordination of iron complexes in the bulk are isotropic, the interfacial bound ions show a signature of a broken inversion-symmetry environment. The XANES of Fe2+ and Fe3+ in the bulk possess distinct profiles however, upon binding they practically exhibit similar patterns. This indicates that both bound ions settle into a stable electronic and coordination configuration with an effective fractional valence (for example, Fe[2+nu]+, 0 < nu < 1) at charged organic templates. Such two dimensional properties may render interfacial iron, abundant in living organisms, a more efficient and versatile catalytic behavior.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-07CH11358
• OSTI ID: 1157659
• Report Number(s): IS-J 8373
• Journal Information: Physical Chemistry Chemical Physics, Journal Name: Physical Chemistry Chemical Physics Journal Issue: 26 Vol. 16; ISSN 1463-9076; ISSN PPCPFQ
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
fe3+
fluorescence
monolayer
reflectivity