Nanocomposites and nanomaterials

Effect of UV irradiation on magnetization dynamics and surface magnetic properties of nanomagnetite doped with noble metals
Lavrynenko O.M., Zahornyi M.N., Bataiev M.M., Bataiev Yu.M., 
Pavlenko O.Yu., and Kornienko O.A.
Frantsevych Institute for Problems of Materials Science, NAS of Ukraine. 
Krzhyzhanovskii Str., 3, Kyiv-03680142, Ukraine.
E-mail: alena.lavrynenko@gmail.com

Functional nanocomposites based on such metal oxides as TiO2, ZnO, and Fe3O4 doped with noble metals and rare earth elements (REE) can be a perspective material for the new kind of bio active photocatalysts creation. Whereas the presence of REE in the structure of the zinc and titanium oxides enhances their photo catalytically activity [1] the inclusion of noble metal cations in the crystal lattice of iron oxides enhances their optical properties [2]. In addition effect UV irradiation on metal oxide catalysts promotes to appearance their photobactericidal activity [3]. The aim of the resent work is to compare magnetization dynamics and surface magnetic properties of as-prepared and UV irradiated nanomagnetite doped with argentum, aurum, platinum, and palladium cations. EPR spectroscopy was chosen as a main method of the investigation. The EPR experimental measurements were performed using commercial Radiopan 2547 SE/X spectrometer. According to obtained data the irradiated samples show the significant shift of EPR lines to the large-field area. Generally, such shift leads to ferrimagnetic properties reinforcement of the irradiated nanocomposites in comparison with non radiated samples. Shift intensity of EPR lines depends on the nature of noble metal dopants, but the spin quantity of the irradiated samples decreases in all cases, except Ag+-bearing sample. The magnetization intensity under UV irradiation is decreasing and became the same values for all investigated samples. The experimental data well correlate with theoretical Lorenz model fit.

1.	Zahornyi M. Functional nanocomposites based of titanium dioxide // Monograph (LAP), 2018.- 157 p. (ISBN: 978-613-8-27486-5).
2.	Xu Z., Hou Y., Sun Sh. Magnetic Core/Shell Fe3O4/Au and Fe3O4/Au/Ag Nanoparticles with Tunable Plasmonic Properties // J. Am. Chem. Soc.-2007.-129, N 28.- P. 8698-8699.
3.	Kartsonakis I.A., Liatsi P., Danilidis I., Bouzarelou D., Kordas G. Synthesis, characterization and antibacterial action of hollow titania spheres // J. Phys. Chem. Solids.-2008.-69.- P. 214-221.