He/H2 Pulsed-Discharge Plasma as a Tool for Synthesis of Surfactant-Free Colloidal Silver Nanoparticles in Water

Abstract

In this study we investigated the interaction of atmospheric-pressure helium (He) and He/ H 2 pulsed-discharge plasma with different water solutions. We developed a synthetic path to obtain fairly uniform, small (~2 nm), surfactant-free silver (Ag) nanoparticles (NPs) with the treatment of an AgNO 3 solution with He/H 2 bipolar pulsed discharge. The colloidal solutions containing Ag NPs are stable for months negatively charged hydroxide (OH ) ions on the surface of Ag NPs could be responsible for the electrostatic stabilization. The treatment of the air-saturated water by pure He plasma with a negative polarity leads to the creation of HNO 3 and hydrogen peroxide (H 2 O 2 solution by He plasma treatment, He/H 2 discharge with negative and, in particular, with bipolar pulses produces only traces of HNO 3 and no H 2 O 2 . We demonstrate here that He/H 2 discharge with bipolar pulses 3 and KNO 3 solutions.