Interaction and transfer of charged particles from an alternating current glow discharge in liquids: Application to silver nanoparticle synthesis

Abstract

In this study, we experimentally investigated the effect of charged particles generated from an alternating current glow discharge in liquids and the ability of these particles to synthesize silver nanoparticles. The measurement of the pH and electrical conductivity in liquids was performed to study the interface reactions and transfer of species from plasmas to liquids. Solutions of sodium hydroxide, de-ionized water, sodium nitrate, and silver nitrate were used in this study. We determined that the pH of de-ionized water and sodium hydroxide solutions was reduced to 4.0 during the discharge. However, the pH of nitrate salts evolved in two opposite stages, with an initial reduction within 3 min from the start of the discharge and a subsequent increase to alkaline values. The results also showed that spherical silver nanoparticles were generated in the silver nitrate solutions under the discharge. These results indicate that alternating current glow discharge generates both positive ions and free electrons when in contact with a liquid, leading to complex chemical transformations. This suggests that the proposed approach can be used for noble nanoparticle synthesis.

Preparation of silver nanoparticles using atmospheric discharge plasma for catalytic reduction of p-nitrophenol: the influence of pressure in the reactor

“…This leads to a large amount of generated solvated electrons that quickly react with water molecules as reaction R3 (Table 2) or NO 3 − ions below the plasma–liquid interface as reaction R8 (Table 2) (Bard et al , 1985). Next, NO 3 2− ions also react with water to generate OH − ions as reaction R9 (Table 2) (Thai et al , 2019). The total number of H + ions generated is larger than the total number of solvated electrons generated during a period influence of the discharge.…”

Bactericidal Silver Nanoparticles by Atmospheric Pressure Solution Plasma Processing

“…Thai et al used Alternative Current (AC) glow discharge plasma to produce spherical nanoparticles. They were able to synthesise nanoparticle sizes varying from three to a few hundred nanometres in a spherical shape [3].…”

“…The redox potential of Ag + /Ag is (+0.799 V), which makes the instant capture of the solvated electrons and synthesis of the reduced silver atoms. The atmospheric pressure plasma may have electrons with an energy level up to 20.2 eV and it is possible for the positive ions to also have energy levels above 10 eV [3]. The following reaction is possible within the few nanometres of the liquid surface.…”

“…Silver (Ag) nanoparticles have been widely studied due to their applications in a broad area of industries, such as biomedical engineering, textiles, healthcare, electronics, optics, and chemical engineering [1][2][3][4]. A number of synthesis techniques have been developed for the generation of silver nanoparticles [5].…”

“…Nanoparticle agglomeration occurs due to the high active surface area and capping agents, such as Poly (Viny Pyrrolidone) (PVP) or Poly (Vinyl Alcohol) (PVA), which are used to prevent the agglomeration of the formed nanoparticles [4]. A number of other methods are also used for the silver nanoparticle synthesis such as biosynthesis, photochemical and sonochemical pathways [3,4]. These techniques still require either several processing steps or time to obtain pure yield of the synthesised product.…”