Тип публикации: статья из журнала
Год издания: 2016
Идентификатор DOI: 10.1016/j.apsusc.2016.06.190
Ключевые слова: HAXPES, XANES, Pyrite, Pyrrhotite, Oxidation, Undersurface, Charge transfer, Chlorination, Electronic properties, Iron ores, Photoelectrons, Photons, Polysulfides, Pyrites, Surface defects, X ray absorption spectroscopy, Ferric chloride solution, Hard X-ray photoelectron spectroscopy, Hax-pes, Interfacial charge transfer, Partial fluorescence yields, X ray photoelectron spectroscopy
Аннотация: 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 pyrrhoПоказать полностьюtite 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.
Журнал: APPLIED SURFACE SCIENCE
Выпуск журнала: Vol. 387
Номера страниц: 796-804
ISSN журнала: 01694332
Место издания: AMSTERDAM
Издатель: ELSEVIER SCIENCE BV