Dielectric Barrier Discharge Plasma-Assisted Catalytic CO2 Hydrogenation: Synergy of Catalyst and Plasma

CO2 hydrogenation is an effective way to convert CO2 to value-added chemicals (e.g., CH4 and CH3OH). As a thermal catalytic process, it suffers from dissatisfactory catalytic performances (low conversion/selectivity and poor stability) and high energy input. By utilizing the dielectric barrier discharge (DBD) technology, the catalyst and plasma could generate a synergy, activating the whole process in a mild condition, and enhancing the conversion efficiency of CO2 and selectivity of targeted product. In this review, a comprehensive summary of the applications of DBD plasma in catalytic CO2 hydrogenation is provided in detail. Moreover, the state-of-the-art design of the reactor and optimization of reaction parameters are discussed. Furthermore, several mechanisms based on simulations and experiments are provided. In the end, the existing challenges of this hybrid system and corresponding solutions are proposed.

Atmosphere Non-Thermal Plasma for Seed Treatment

Cold plasma has attracted lots of attention among researchers because it has a wide range of applications, such as the automotive industry, textile industry, microelectronics, packaging, biomedical technology, food preservation, and agricultural sectors. Scientists have shown a great interest in non-thermal plasma because of its advantages such as low temperature, scalable size, low operation cost, flexible operation, and high electron and reactive specie density. Also, non-thermal plasma can be operated at atmospheric pressure, which is an advantage in the agriculture industry rather than operating in a vacuum. Recently atmospheric cold plasma pressure was selected as one of the plasma technologies applied in the agricultural industry for treating the surface of the seed with environmentally friendly technology that produces no hazardous waste. DBD plasma is one of the cold plasma techniques, which can be easily triggered at atmospheric pressure and room temperature.

Biosynthesis of Silver Nanoparticles for Study of Their Antimicrobial Effect on Plasma-Treated Textiles

Dielectric barrier discharges (DBD) are the configurations for the production of electrical discharges using a dielectric medium between the metallic electrodes. Plasma treatment produces negative radicals, which increase the adhesion of fabric for nanoparticles. The plasma treatment made the fabric surface rougher because of the etching effect. UV-vis spectra of the Plasmon resonance band observed at 253-400 nm. X-ray diffraction results showed that AgNPs has a cubical structure and the average crystalline size is 25 nm. SEM results determined that the morphology of the silver nanoparticles are flower shaped. The energy bandgap of AgNPs was observed at 2.59 eV. The silver nanoparticles were found to have enhanced antimicrobial properties and showed better zone of inhibition against isolated bacteria (Escherichia coli). DBD plasma treatment changed the chemical as well as physical properties of the cotton fabric. FTIR spectrum revealed that oxygen-containing groups, such as C-O, C=O, O-C-O, as well as O-C=O, increased on DBD treatment of cotton samples.

Plasma Generator with Dielectric Rim and FSS Electrode for Enhanced RCS Reduction Effect

In this study, a method was experimentally verified for further reducing the radar cross-section (RCS) of a two-dimensional planar target by using a dielectric rim in a dielectric barrier discharge (DBD) plasma generator using a frequency selective surface (FSS) as an electrode. By designing the frequency selective surface such that the passbands of the radar signal match, it is possible to minimize the effect of the conductor electrode, in order to maximize the RCS reduction effect due to the plasma. By designing the FSS to be independent of the polarization, the effect of RCS reduction can be insensitive to the polarization of the incoming wave. Furthermore, by introducing a dielectric rim between the FSS electrode and the target, an additional RCS reduction effect is achieved. By fabricating the proposed plasma generator, an RCS reduction effect of up to 6.4 dB in X-band was experimentally verified.

Dynamic Burst Actuation to Enhance the Flow Control Authority of Plasma Actuators

A computational study was conducted on flows over an NACA0015 airfoil with dielectric barrier discharge (DBD) plasma. The separated flows were controlled by a DBD plasma actuator installed at the 5% chord position from the leading edge, where operated AC voltage was modulated with the duty cycle not given a priori but dynamically changed based on the flow fluctuations over the airfoil surface. A single-point pressure sensor was installed at the 40% chord position of the airfoil surface and the DBD plasma actuator was activated and deactivated based on the strength of the measured pressure fluctuations. The Reynolds number was set to 63,000 and flows at angles of attack of 12 and 16 degrees were considered. The three-dimensional compressible Navier–Stokes equations including the DBD plasma actuator body force were solved using an implicit large-eddy simulation. Good flow control was observed, and the burst frequency proven to be effective in previous fixed burst frequency studies is automatically realized by this approach. The burst frequency is related to the characteristic pressure fluctuation; our approach was improved based on the findings. This improved approach realizes the effective burst frequency with a lower control cost and is robust to changing the angle of attack.

Effect of dielectric barrier discharge on conductive properties for epoxy/copper composite

The plasma treatment efficient method used improving and Surface treatment of epoxy and increasing the surface roughness. In this paper, epoxy and epoxy/copper are modified by dielectric barrier discharge (DBD) Plasma in presence of air. Modification of the properties of epoxy by preparing doping systems with percentage 1% copper with two different frequencies of the plasma f=7 and 8 kHz and exposure time t =10 min. The results showed a decrease in the energy gap when exposed to plasma and an increase in the surface roughness of epoxy, electrical conductivity of composites increased with temperature.