NDLI: Layered structure of the near-surface region of oxidized chalcopyrite (CuFeS<sub>2</sub>): hard X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and DFT+U studies

Content Provider	Royal Society of Chemistry (RSC)
Author	Nasluzov, Vladimir Tomashevich, Yevgeny Mikhlin, Yuri Shor, Alexey Romanchenko, Alexander Félix, Roberto
Copyright Year	2017
Abstract	The depletion of oxidized metal sulfide surfaces in metals due to the preferential release of cations is a common, but as yet poorly understood phenomenon. Herein, X-ray photoelectron spectroscopy using excitation energies from 1.25 keV to 6 keV, and Fe K- and S K-edge X-ray absorption near-edge spectra in total electron and partial fluorescence yield modes was employed to study natural chalcopyrite oxidized in air and etched in an acidic ferric sulfate solution. The metal-depleted undersurface formed was found to consist of a thin, 1–4 nm, outer layer containing polysulfide species, a layer with a pronounced deficiency of metals, mainly iron, and an abundant disulfide content but negligible polysulfide content (about 20 nm thick after the chemical etching), and a defective underlayer which extended down to about a hundred nm. DFT+U was used to simulate chalcopyrite with increasing numbers of removed Fe atoms. It was found that the structure with disulfide anion near double Fe vacancies, and the ‘defective’ structure comprising Cu in the position of Fe and Cu vacancy are most energetically favorable, especially when using a higher Hubbard-type parameter U, and have a large density of states at the Fermi level, whereas polysulfide anions are stable only near the surface. We propose a mechanism explaining the formation of the layered undersurface and ‘passivation’ of metal sulfides by (i) arrested decomposition of a nearly stoichiometric sulfide surface, and (ii) faster interfacial transfer and solid diffusion of cations towards the surface; (iii) stability limits for specific defect structures, promoting their expansion in depth rather than through compositional changes, excluding surface layers; (iv) decay of surface polysulfide layer yielding elemental sulfur.
Starting Page	2749
Ending Page	2759
Page Count	11
File Format	HTM / HTML PDF
ISSN	14639076
Volume Number	19
Issue Number	4
Journal	Physical Chemistry Chemical Physics
DOI	10.1039/c6cp07598c
Language	English
Publisher	Royal Society of Chemistry
Access Restriction	Open
Subject Keyword	Sulfide Spectroscopy Stoichiometry Electronvolt Ion Photoemission spectroscopy Polysulfide Chalcopyrite Fermi level Disulfide Iron(III) sulfate Weathering K-edge X-ray absorption spectroscopy Diffusion Sulfur X-ray photoelectron spectroscopy Passivation (chemistry)
Content Type	Text
Resource Type	Article
Subject	Physics and Astronomy Physical and Theoretical Chemistry

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Preparation, characterization and thermal evolution of oxygen passivated nanocrystalline cobalt

In situ study of oxidation states of platinum nanoparticles on a polymer electrolyte fuel cell electrode by near ambient pressure hard X-ray photoelectron spectroscopy

UV-Photochemistry of the Disulfide Bond: Evolution of Early Photoproducts from Picosecond X-ray Absorption Spectroscopy at the Sulfur K-Edge

Studies of the thermal decomposition of βNiO(OH) and nickel peroxide by X-ray photoelectron spectroscopy

Profiling the nanoscale gradient in stoichiometric layered cathode particles for lithium-ion batteries

A facile and low cost strategy to synthesize Cd_1−xZn_xSe thin films for photoelectrochemical performance: effect of zinc content

Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

Identifying reaction intermediates and catalytic active sites through in situ characterization techniques

Controlled synthesis of thorny anatase TiO₂ tubes for construction of Ag–AgBr/TiO₂ composites as highly efficient simulated solar-light photocatalyst

Layered structure of the near-surface region of oxidized chalcopyrite (CuFeS₂): hard X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and DFT+U studies

Similar Documents

Preparation, characterization and thermal evolution of oxygen passivated nanocrystalline cobalt

In situ study of oxidation states of platinum nanoparticles on a polymer electrolyte fuel cell electrode by near ambient pressure hard X-ray photoelectron spectroscopy

UV-Photochemistry of the Disulfide Bond: Evolution of Early Photoproducts from Picosecond X-ray Absorption Spectroscopy at the Sulfur K-Edge

Studies of the thermal decomposition of βNiO(OH) and nickel peroxide by X-ray photoelectron spectroscopy

Profiling the nanoscale gradient in stoichiometric layered cathode particles for lithium-ion batteries

A facile and low cost strategy to synthesize Cd1−xZnxSe thin films for photoelectrochemical performance: effect of zinc content

Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

Identifying reaction intermediates and catalytic active sites through in situ characterization techniques

Controlled synthesis of thorny anatase TiO2 tubes for construction of Ag–AgBr/TiO2 composites as highly efficient simulated solar-light photocatalyst

Layered structure of the near-surface region of oxidized chalcopyrite (CuFeS2): hard X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and DFT+U studies

A facile and low cost strategy to synthesize Cd_1−xZn_xSe thin films for photoelectrochemical performance: effect of zinc content

Controlled synthesis of thorny anatase TiO₂ tubes for construction of Ag–AgBr/TiO₂ composites as highly efficient simulated solar-light photocatalyst

Layered structure of the near-surface region of oxidized chalcopyrite (CuFeS₂): hard X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and DFT+U studies