Nanocomposites and nanomaterials

Silica-supported holmium–ytterbium nanocomposites:
electrophoretic and morphological studies
I.Ya. Sulym1, M.V. Borysenko1, D. Sternik2,
K. Terpilowski2, M. Wiśniewska2, A. Deryło-Marczewska2
1Chuiko Institute of Surface Chemistry, NASU, 17 General Naumov Str., 03164 Kyiv, Ukraine. E-mail: irynasulym@ukr.net.
2Institute of Chemical Sciences,  Faculty of Chemistry, Maria Curie-Skłodowska University, 3 Maria Curie-Skłodowska Sq., 20-031 Lublin, Poland.

In recent years, the production of nanostructured materials doped with trivalent lanthanide ions has drawn tremendous attention owing to their wide range of significant and unique properties as well as potential applications in solid state lasers, color displays, wavelength-calibration tools, catalysts and biolabels [1, 2].
In this work, we focused on studies of electrophoretic and morphological properties of Ho2O3–Yb2O3/SiO2 nanocomposites. The ternary oxides were prepared by a liquid-phase method at room temperature using the water salt solutions of Ho(NO3)3 and Yb(NO3)3 and fumed silica (SBET = 265 m2/g) powder. The mixtures were stirred in the beaker using propeller stirrer for 0.5 hour. Water was removed from the mixtures in rotary evaporator. Then the solid product was dried and calcined at 550 °С for 1 h. The samples were marked as HoYbSi1, HoYbSi2 and HoYbSi3 with molar ratio of Ho2O3:Yb2O3 like 0.1:0.8, 0.2:0.8, and 0.4:0.8, respectively. The stability and aggregation kinetic studies of the initial silica and mixed oxides suspensions without and with the polymer were performed using turbidimeter Turbiscan LabExpert (Formulaction). Additionally, the particle size distribution and zeta potential of examined systems were determined applying a Zetasizer 3000 (Malvern Instruments) apparatus based on photon correlation spectroscopy. The obtained results enabled explanation of stability mechanism of solid particles (bare or covered with polymeric layers) dispersed in liquid medium. The SEM results reveal the preparation of the agglomerated sphere-like Ho2O3–Yb2O3/SiO2 nanostructures with fine size.
Acknowledgement: The authors acknowledge financial support by the Visegrad Fund supporting the study stay of Dr. I. Sulym (Contract number 51910525) at the UMCS.
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