Investigation of silver nanoparticle synthesis with various nonthermal plasma reactor configurations

In this work is investigated the effect of nonthermal plasma reactor configurations on the synthesis of silver nanoparticle (AgNP) comparing three reactor configurations: (i) coaxial dielectric barrier discharge (DBD), (ii) like-free ground DBD, and (iii) corona plasma discharge. To make the AgNP synthesis cost-effective and eco-friendly, no reducing agent was used and to get stable particles, instead inexpensive sucrose was used as capping agent. The formation and stability of AgNP were verified using ultraviolet–visible (UV–Vis) spectroscopy and energy dispersive spectroscopy (EDS). The concentration and stability of AgNP were found to be dependent on various process parameters, with the optimal conditions of applied voltage, gas flow rate, treatment time, nozzle distance, silver nitrate concentration and sucrose concentration determined at 12 kV, 1.5 L/min, 180 s, 1.0 cm, 0.5 mM, and 20 mM, respectively. The surface morphology and particle size distribution (PSD) obtained with transmission electron microscopy (TEM) showed that the nanoparticle (NP) synthesized by coaxial DBD and corona plasma were spherical in shape with a wide PSD, and their average size was 6.2 nm and 9.6 nm, respectively. On the other hand, those NP synthesized by like-free ground DBD were mostly spherical, along with a few hexagon and triangular shapes. With like-free ground DBD, the PSD was found to be significantly narrower, and the average particle size was 20 nm which is bigger compared to NP synthesized by coaxial DBD and corona plasma. Better performance of AgNP synthesis by the like-free ground DBD is most likely due to higher energy delivery capacity