Mössbauer spectroscopy analysis of iron compounds in carboxylated multiwall carbon nanotubes and their ammonium salt

Agnieszka Jamrozik , Marta Mazurkiewicz , Artur Małolepszy , Leszek Stobiński , Krzysztof Matlak , Józef Korecki , Krzysztof Kurzydłowski , Kvĕtoslava Burda

Abstract

Different forms of iron compounds embedded in non-functionalized (as prepared) and functionalized multiwall carbon nanotubes (MWCNTs) were studied. Iron used to catalyze MWCNT synthesis can be found inside nanotubes and built-in within their walls. Mössbauer spectroscopy was applied to study valence and spin states as well as magnetic ordering of the iron compounds. In the Mössbauer spectra of as prepared MWCNTs the Fe3C carbide provides the main contribution. The content of Fe3C decreases by about 20 and 40\% in carboxylated carbon nanotubes (MWCNTs-COOH) and ammonium salt of carboxylated carbon nanotubes (MWCNTs-COONH4), respectively. A small amount of α-Fe and FexCx iron forms are always observed in all studied carbon nanotubes. In MWCNTs-COOH, additionally, ferrihydrates and/or FexCy with oxygen in the second coordination sphere of iron are present (at a level of about 17\%). In MWCNTs-COONH4 their content increases by a factor of 3. The experimental data shows that the purification and functionalization of as prepared MWCNTs result in removal of about 90\% of iron contaminations. Additionally, we observe the modification of iron compounds inside MWCNTs. All these results are important in optimizing the as prepared MWCNT purification process and in finding a new way to produce different Fe phases inside MWCNTs.
Author Agnieszka Jamrozik - [AGH University of Science and Technology (AGH)]
Agnieszka Jamrozik,,
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- Akademia Górniczo-Hutnicza
, Marta Mazurkiewicz - [Politechnika Warszawska]
Marta Mazurkiewicz,,
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, Artur Małolepszy - [Warsaw University of Technology (PW), MNiSW [80]]
Artur Małolepszy,,
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- Politechnika Warszawska
, Leszek Stobiński - [Politechnika Warszawska]
Leszek Stobiński,,
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, Krzysztof Matlak - [AGH University of Science and Technology (AGH)]
Krzysztof Matlak,,
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- Akademia Górniczo-Hutnicza
, Józef Korecki - [AGH University of Science and Technology (AGH)]
Józef Korecki,,
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- Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
, Krzysztof Kurzydłowski (FMSE / DMD)
Krzysztof Kurzydłowski,,
- Division of Materials Design
, Kvĕtoslava Burda - [AGH University of Science and Technology (AGH)]
Kvĕtoslava Burda,,
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- Akademia Górniczo-Hutnicza
Journal seriesphysica status solidi (a), ISSN 1862-6319, (0 pkt)
Issue year2011
Vol208
No8
Pages1783–1786
Keywords in EnglishCarbon nanotubes, functionalization, iron states, Mössbauer spectroscopy
DOIDOI:10.1002/pssa.201001210
URL http://onlinelibrary.wiley.com/doi/10.1002/pssa.201001210/abstract
Score (nominal)0
Score sourcejournalList
Publication indicators Scopus Citations = 9; WoS Citations = 9
Citation count*6 (2015-04-27)
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