Application of Direct Current Atmospheric Pressure Glow Microdischarge Generated in Contact with a Flowing Liquid Solution for Synthesis of Au-Ag Core-Shell Nanoparticles

Abstract

A direct current atmospheric pressure glow microdischarge (dc-μAPGD) generated between an Ar nozzle microjet and a flowing liquid was applied to produce Au-Ag core-shell nanoparticles (Au@AgCSNPs) in a continuous flow system. Firstly, operating dc-μAPGD with the flowing solution of the Au(III) ions as the cathode, the Au nanoparticles (AuNPs) core was produced. Next, to produce the core-shell nanostructures, the collected AuNPs solution was immediately mixed with an AgNO3 solution and passed through the system with the reversed polarity to fabricate the Ag nanoshell on the AuNPs core. The formation of Au@AgCSNPs was confirmed using ultraviolet-visible (UV-Vis) absorbance spectrophotometry, transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Three localized surface plasmon resonance absorption bands with wavelengths centered at 372, 546, and 675 nm were observed in the UV-Vis spectrum of Au@AgCSNPs, confirming the reduction of both the Au(III) and Ag(I) ions. The right configuration of metals in Au@AgCSNPs was evidenced by TEM. The Au core diameter was 10.2 ± 2.0 nm, while the thickness of the Ag nanoshell was 5.8 ± 1.8 nm. The elemental composition of the bimetallic nanoparticles was also confirmed by EDS. It is possible to obtain 90 mL of a solution containing Au@AgCSNPs per hour using the applied microdischarge system.

Production of antimicrobial silver nanoparticles modified by alkanethiol self‐assembled monolayers by direct current atmospheric pressure glow discharge generated in contact with a flowing liquid anode

“…TMA allows to obtain stable nanoparticles, as well as noncytotoxic AgNPs with antimicrobial potential . Previously, dc‐APGD or pulse‐modulated radio‐frequency atmospheric pressure glow discharge (pm‐rf‐APGD), operated between the surface of flowing liquid electrodes and pin‐type W electrodes or a gaseous nozzle jet, was used in our group to synthesize Ag or Ag‐Au core‐shell nanostructures. Until now, operating conditions for production of size‐defined Ag nanostructures have only been optimized for the pm‐rf‐APGD reaction‐discharge system; no dc‐APGD reaction‐discharge system has been previously been optimized for that purpose.…”

Rapid eradication of bacterial phytopathogens by atmospheric pressure glow discharge generated in contact with a flowing liquid cathode

“…Such measures could involve atmospheric pressure plasma (APP) sources of antimicrobial properties due to generated electrons, ions, heat, UV light, electric field, and various active species, and radicals (Ikawa, Kitano, & Hamaguchi, ). APP can be produced with the aid of various sources, including dielectric barrier discharges (DBDs) (Butscher, Van Loon, Waskow, Rudolf von Rohr, & Schuppler, ; Lu, Liu, Song, Zhou, & Niu, ; Miao & Yun, ; Shen et al, ; Tiede, Hirschberg, Viöl, & Emmert, ; Xiong, Roe, Grammer, & Graves, ; Yong et al, ), corona discharges (Kuwahara, Kuroki, Yoshida, Saeki, & Okubo, ; Masaoka, ), radio frequency discharges and plasmas (Akitsu, Ohkawa, Tsuji, Kimura, & Kogoma, ; Laroussi et al, ; Li et al, ; Matan, Puangjinda, Phothisuwan, & Nisoa, ; Ohkawa et al, ), microwave discharges (Gabriel et al, ; Park et al, ), and glow discharges (GD) (Dzimitrowicz et al, ,; Ikawa et al, ). To the best of our knowledge, DBD (Lu et al, ; Tiede et al, ; Xiong et al, ) and radio frequency discharges and plasmas (Laroussi et al, ; Ohkawa et al, ) have been implemented for microbiological and biomedical applications so far.…”

Direct current atmospheric pressure glow discharge generated between a pin‐type solid cathode and a flowing liquid anode as a new tool for silver nanoparticles production

“…Over past few years, a significant interest in new applications of plasma‐liquid interactions (PLIs) has been observed, particularly in relation to their usage in environmental engineering, microbiology, analytical chemistry, and nanotechnology . The use of large quantities of nanomaterials, especially silver (AgNPs) and gold nanoparticles (AuNPs) of well‐defined optical properties and morphology, appears to be necessary nowadays in a broad range of application fields, including medicine, sensing, environmental engineering, and catalysis .…”

“…Their use in nanomaterials synthesis only depends on generation of different reactive species, for example, hydrated electrons , hydrogen ions (H + ), hydrogen radicals (H), hydroxyl radicals (OH • ) and hydrogen peroxide (H 2 O 2 ), and other phenomena occurring at the plasma‐liquid interface and being responsible for suitable reducing conditions for the metallic nanoparticles precursors . Introduction of the additional reducing agents in such plasma‐reaction systems is completely unnecessary, hence, operational costs are highly decreased, while the whole nanomaterials synthesis is simplified …”

“…All of the above‐cited plasma‐reaction systems, used for synthesis of AuNPs and AgNPs through PLIs, unfortunately worked in a non‐flow through mode and hence allowed to produce only limited amounts of the nanomaterials. Due to unsatisfactory yield of the nanomaterials achieved by the methods presented above, our research group developed a flow‐through plasma‐reaction system for effective synthesis of AuNPs and increased total output of the nanomaterials . In the developed system, direct current atmospheric pressure glow discharge (dc‐APGD), sustained between a dc Ar plasma jet and the surface of a solution of a flowing liquid cathode (FLC) or anode (FLA), was used for synthesis of AuNPs and Au‐Ag core‐shell NPs in the presence of gelatin (GEL) as capping agent …”