Atmospheric pressure plasma in contact with liquid and its application for nanoparticles synthesis

The capabilities of atmospheric pressure gas-liquid interfacial discharge plasma for synthesis of metallic (Ag), oxide (ZnO) and composite (ZnO/Ag) nanoparticles are discussed. The gas-liquid boundary microplasma was generated between a capillary (hollow needle) with flowing argon and liquid surface in ambient air under the normal pressure. To optimize the synthesis process the main characteristics of the discharge plasma were studied using emission spectroscopy by varying the discharge current, gas flow rate and solution composition. The morphology and composition of the generated particles were found to be dependent on both plasma parameters and plasma induced processes in solution. The studies performed suggest that particle nucleation and growth can be attributed to the reduction reactions of the aqueous metal cations by electrons from the microplasma.