Mössbauer and Raman spectroscopic study of oxidation and reduction of iron oxide nanoparticles...

[Z. Klencsar]

S.W. da Silva, L.R. Guilherme, A.C. de Oliveira, V.K. Garg, P.A.M. Rodrigues, J.A.H. Coaquira, Q. da Silva Ferreira, G.H.F. de Melo, A. Lengyel, R. Szalay, Z. Homonnay, Z. Klencsár, Gy. Tolnai, E. Kuzmann:
Mössbauer and Raman spectroscopic study of oxidation and reduction of iron oxide nanoparticles promoted by various carboxylic acid layers
J. Radioanal. Nucl. Chem. 312 (2017) 111–119. ( http://dx.doi.org/10.1007/s10967-017-5195-0 )

In our project the preparation of suitable nanoparticles is a prerequisite for progress. Two of the iron-bearing nanoparticle types interesting to us are magnetite and maghemite. When prepared with a size in or below the order of a few times of 10 nm, corresponding nanoparticles may display properties that makes it ambiguous whether they are magnetite, maghemite, a mixture of them (e.g. core-shell particles), or an intermediate form that may also be called as non-stoichiometric magnetite. In order to find suitable means by which one can ascertain the nature of the magnetite/maghemite nanoparticles prepared, one may proceed by preparing a series of magnetite nanoparticle samples subjected to different levels of oxidation, and investigating the physical and chemical properties of the nanoparticles as a function of non-stoichiometry associated with these levels. In the present work a similar situation is realized, by applying nine different carboxylic (glycolic, propionic, lactic, malic, tartaric, citric, mandelic, caproic and caprylic) acids to coat magnetite nanoparticles, which turns out to result in different levels of oxidation of the coated nanoparticles depending on the type of carboxylic acid used in the experiments.

The final publication can be accessed via the link http://dx.doi.org/10.1007/s10967-017-5195-0 .
The authors' version of the work can be downloaded directly from here: http://www.esr.hu/aam/aam_jrnc_2017.pdf