7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Synthesis of metal nanoparticles from DC discharge plasmas insider a solution
Qiang Chen, Binhong Wu
Institute of Electromagnetics and Acoustics, Fujian Provincial Key Laboratory of Plasma andMagnetic Resonance, Key Laboratory of Electromagnetic Wave Science and Detection Technology,Xiamen University, Xiamen 361005, Chinae-mail (speaker): chenqiang@xmu.edu.cn

Plasmas in contact with liquids provide a novel reaction
zone for synthesizing many chemicals and materials[1-3]. When plasma is operated inside liquid, the gaseous
reactive species generated via the plasma-liquidinteractions can efficiently transport into the liquid phase,
which makes the plasma insider water is more suitable
for materials synthesis, compare with the plasma
generated over a liquid surface. This work designs a DC
liquid discharge plasma device, which overcomes thedisadvantage that liquid discharge usually requires
expensive high-voltage alternating current power supply.
The device is mainly composed of a pair of tungsten wire
electrodes, respectively, wrapped in a capillary quartz
tube, one electrode tip is insider the capillary tube, andthe other electrode extends out of the capillary tube.
When the two capillary quartz tubes are immersed in theliquid, there will be a small gas gap between the tungsten
wire electrodes that do not protrude from the capillarytubes and the liquid. A discharge plasma can be ignitedand sustained between the gas gap by applied a DC
voltage. The reactivity of the plasma can be converted
into the reactivity of the liquid through the plasma-liquidinterface, so the device can be used in various fields,such as plasma activated water, pollution control,
nanomaterial synthesis, nitrogen fixation and hydrogen
peroxide synthesis, etc.
Based on the anodic dissolution, we used this plasma
source to synthesize several metal nanoparticles,
including gold, silver, copper nanoparticle by using
respective metallic anode material, and the properties ofnanoparticles can be tuned by the discharge parameterssuch as electrode configuration, solution composition,discharge current etc. Figure 1 presents the case ofsynthesis of gold nanoparticles. Obviously, the typical
localized surface plasmon resonance appears at theabsorbance of the plasma treated solutions. We also
discussed the formation processes of the gold, silver, andcopper nanoparticles at different solution and plasma
parameters.

References[1] P. Bruggeman, M.J. Kushner, B.R. Locke, J.G.
Gardeniers, W. Graham, D.B. Graves, R. Hofman-Caris,
D. Maric, J.P. Reid, E. Ceriani, Plasma–liquidinteractions: a review and roadmap, Plasma sourcesscience and technology, 25 (2016) 053002.
[2] Q. Chen, J. Li, Y. Li, A review of plasma–liquidinteractions for nanomaterial synthesis, Journal ofPhysics D: Applied Physics, 48 (2015) 424005.
[3] F. Rezaei, P. Vanraes, A. Nikiforov, R. Morent, N. DeGeyter, Applications of plasma-liquid systems: A review,Materials, 12 (2019) 2751.
Acknowledgments
We thank the National Natural Science Foundation ofChina (No. 52077185).

Figure 1．Absorbance of plasma treated aqueous solutions with different surfactant componenets of (a) SDS/CTAB, (b)PVP/CTAB. Gold wire acts as the gold precursor released by anodic dissolution.