Silver nanoparticles (AgNPs) are novel materials with antibacterial, antifungal, and antiviral activities over a wide range. This study aimed to prepare polyvinylpyrrolidone (PVP) electrospinning composites with uniformly distributed AgNPs. In this study, starch-capped ~2 nm primary AgNPs were first synthesized using Atmospheric pressure Pulsed Discharge Plasma (APDP) at AC 10 kV and 10 kHz. Then, 0.6 wt.% AgNPs were mixed into a 10 wt.% PVP ethanol-based polymer solution and coiled through an Ultrasonic-assisted Electrospinning device (US-ES) with a 50 W and 50 kHz ultrasonic generator. At 12 kV and a distance of 10 cm, this work successfully fabricated AgNPs-PVP electrospun fibers. The electrospun products were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), High-Resolution TEM (HR-TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Thermogravimetric (TG), and X-ray Photoelectron Spectroscopy (XPS) methods.

Cerium dioxide (CeO 2 ) nanoparticles have gained immense attention owing to their use in various applications. Current synthesis methods for CeO 2 nanoparticles including hydrothermal and chemical precipitation are time-consuming and require chemical reagents. In order to shorten the reaction time and avoid the use of organic reagents, a new method for CeO 2 nanoparticles synthesis in a slug flow system by atmospheric-pressure pulsed discharge plasma was proposed, which provided an easy, efficient, and continuous reaction at room temperature. Cerium nitrate was used as a feed solution, and starch was added as a stabilizer to separate the nucleation and growth processes of the nanoparticles to prevent their aggregation. The system was powered by a high voltage of 10.0 kV (peak-to-peak) from an ac power supply. The products were characterized by transmission electron microscopy (TEM), high-resolution TEM, energy-dispersive X-ray spectroscopy, and UV−vis spectroscopy. The results showed that when a circular capillary glass tube coil was used as the slug flow reactor, the amount of the CeO 2 nanoparticles increased compared to the case when a straight glass tube was used. The size also increased from 3.4 to 6.3 nm. The synthesis mechanism of the CeO 2 nanoparticles by gas/liquid plasma was finally elucidated.

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Pulsed discharge plasma produced in a gas/liquid environment has attracted much attention because of its low energy requirement and the generation of various radical species with high reactivity. In our previous work, a slug flow system was developed to produce gas/liquid plasma under atmospheric pressure, generating continuous bubbles and stable gas–liquid interfaces. Currently, meaningful results have also been obtained in the field of plasma under high-pressure conditions. Therefore, in this study, a slug flow system using gas/liquid discharge plasma was implemented under pressurized argon. The system pressure was controlled from 0.1 (atmospheric pressure) to 0.4 MPa, and the effect of pressure on the system was investigated. This system was also applied to the decomposition of methylene blue. The chemical reactivity was studied, and the energy of the system was calculated. The results showed that as the system pressure increased, the decomposition rate of methylene blue decreased, while the concentration of the total oxidation species increased. This can be explained by a decrease in the energy available for methylene blue decomposition owing to the steady input energy and increasing energy loss.

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