Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides
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http://www.sciencedirect.com/science/journal/01694332/387?sdc=1https://elib.sfu-kras.ru/handle/2311/70113
Автор:
Mikhlin, Yuri
Tomashevich, Yevgeny
Vorobyev, Sergey
Saikova, Svetlana
Romanchenko, Alexander
Felix, Roberto
Коллективный автор:
Институт цветных металлов и материаловедения
Кафедра физической и неорганической химии
Дата:
2016-11Журнал:
Applied Surface ScienceКвартиль журнала в Scopus:
Q1Квартиль журнала в Web of Science:
Q1Библиографическое описание:
Mikhlin, Yuri. Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides [Текст] / Yuri Mikhlin, Yevgeny Tomashevich, Sergey Vorobyev, Svetlana Saikova, Alexander Romanchenko, Roberto Felix // Applied Surface Science. — 2016. — Т. 387. — С. 796-804Аннотация:
Hard X-ray photoelectron spectroscopy (HAXPES) using an excitation energy range of 2 keV to 6 keV in combination with Fe K- and S K-edge XANES, measured simultaneously in total electron (TEY) and partial fluorescence yield (PFY) modes, have been applied to study near-surface regions of natural polycrystalline pyrite FeS2 and pyrrhotite Fe1-xS before and after etching treatments in an acidic ferric chloride solution. It was found that the following near-surface regions are formed owing to the preferential release of iron from oxidized metal sulfide lattices: (i) a thin, no more than 1-4 nm in depth, outer layer containing polysulfide species, (ii) a layer exhibiting less pronounced stoichiometry deviations and low, if any, concentrations of polysulfide, the composition and dimensions of which vary for pyrite and pyrrhotite and depend on the chemical treatment, and (iii) an extended almost stoichiometric underlayer yielding modified TEY XANES spectra, probably, due to a higher content of defects. We suggest that the extended layered structure should heavily affect the near-surface electronic properties, and processes involving the surface and interfacial charge transfer. (C) 2016 Elsevier B.V. All rights reserved.