Solvothermal hot injection AgNi nanoalloy preparation


                  Vít Vykoukal^1, Jiří Buršík^2, Pavla Roupcová^2, Jiří Pinkas^1*

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^1 Masaryk University, Faculty of Science, Department of Chemistry, Kotlářská 2, 611 37 Brno, Czech
                                             Republic

        ^2 Institute of Physics of Materials, ASCR, Žižkova 22,616 62 Brno, Czech Republic

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                                       jpinkas@chemi.muni.cz


Chemical synthesis of nanomaterials is a very progressive field of study. Preparation of nanoalloys
is a challenging task due to their chemical, phase, and morphological variability. Nanoparticles of
metal alloys exhibit many interesting properties, such as depression of melting point,^1,2,3
plasmon resonance^4,5, magnetism, and catalytic activity. For nanoalloys preparation, the
solvothermal synthesis, specifically in oleylamine is highly advantageous.^6,7 Hot injection
technique should ensure homogeneous conditions for nanoparticles nucleation and growth.


AgNi nanoparticles were prepared by injection of an oleylamine solution (4 cm^3) of AgNO[3] and
Ni(acac)[2] (different ratios, 4 mmol total amount) to a mixture of oleylamine (16 cm^3) and
octadecene (20 cm^3) at 230 °C. After 10 minutes, the reaction mixture was cooled down to room
temperature in a water bath. Then 20 cm^3of acetone was added and the mixture was centrifuged.
Acetone was added to increase the yield. The precipitate was washed by a mixture of hexane and
acetone (1:3 volume ratio). This procedure was repeated twice and finally the precipitate was
dispersed in hexane and characterized.


Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Small-Angle X-ray
Scattering (SAXS) analyses were carried out for determination of average size, size distribution,
and shape of prepared nanoparticles. Obtained results were mutually compared. Thermal behavior was
characterized by Differential Scanning Calorimetry (DSC). Plasmon resonances were observed and we
found out that the intensity of plasmon resonance was dependent on the molar ratio of AgNi in the
particles.


References

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[7] Sopoušek, J.; Pinkas, J.; Brož, P.; Buršík, J.; Vykoukal, V.; Škoda, D.; Stýskalík, A.; Zobač,
O.; Vřešťál, J.; Hrdlička, A.; Šimbera, J. J. Nanomater. 2014, 2014, 1–13.