Nanocomposites and nanomaterials
Iron oxide nanorods, decoratied by gold nanoparticals
Shumskaya A.*, Abakshonok A., Ignatovich Zh., Rogachev A.
Institute of Chemistry of New Materials, National Academy of Science of Belarus, Minsk, 220141, F. Skariny, 36
*E-mail: lunka7@mail.ru
Composite nanomaterials including gold and iron oxides are promising for applications in biotechnology and catalysis. 
Iron oxides nanorods decoratied with gold nanoparticles were synthesis by co-precipitation method from the cooled solution, containing 0.04 N HCl, 15 mM FeSO4, 30 mM FeCl3 and 0,5 (Sample 1) and 20 (Sample 2) mM HAuCl4, and solution 2 including 100 mM N2H42HCl and 2.2 М NH3H2O were prepared. 1 part of solution 1 was added to 9 parts of solution 2 and resulting mixture was treated for 3 hours in the ultrasonic bath Elmasonic S30H (Germany).
The resulting composite is iron oxide nanorods surrounded by gold nanoparticles (Fig. a, TEM, JEOL JEM-100). The demention and concentration of components in composite depends on the synthesis conditions. The chemical and phase composition analisys (by using XRD, DRON) shows characteristics patterns of magnetite nanoparticles with gold nanoparticals. Gold acts as an independent phase with a fcc structure with a dominant growth direction [111] and does not form an alloy with magnetite particles. The magnetic parameters calculated from the hysteresis loops (studied by VSM, Cryogenic LTD in magnetic fields ±2 T at 300 K) for sample Sample 1 have values: the coercivity is about 2 Oe and the squareness of the 0.0075 hysteresis loops is saturation magnetization is 35 emu / g., which is typical for magnetic Fe3O4 nanoparticles mixed with another non-magnetic composite. For sample Sample 2, the coercivity is about 5 Oe and the squareness of the hysteresis loops is 0.005, and the saturation magnetization is 41 emu / g. The hysteresis loops of both composites have the form characteristic of nanoparticles of superparamagnetic materials.