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As carbon monoxide has a broad spectrum of biological activities, its production by plasma is a significant advantage in medicine. This paper presents a comparative study of the CO production of two plasma jets: a MHz‐jet and a kHz‐jet. Both were fed with a helium gas with CO2 ${\text{CO}}_{2}$ admixture (0%–1%). CO was produced by CO2 ${\text{CO}}_{2}$ dissociation and its maximal concentration was hundreds of parts per million, which is safe for clinical applications. For the same specific energy input, the CO production was more efficient for the kHz‐jet than the MHz‐jet. Both had antibacterial properties on Escherichia coli, and the addition of CO2 ${\text{CO}}_{2}$ improved them for the MHz‐jet, while it reduced them for the kHz‐jet. [ABSTRACT FROM AUTHOR]

Solution‐based amine absorption technologies have been widely applied for CO2 capture, but they have several drawbacks. This paper reports on the synthesis of the first solid‐state amine adsorbent prepared through a simple plasma polymerization and deposition on physicochemically modified natural mordenite–clinoptilolite zeolite. The plasma deposition of amine polymer under certain conditions resulted in a significant increase in surface area‐weighted CO2 adsorption capacity as the natural zeolite. The strength of the interaction between CO2 and the adsorbent was weaker for the plasma polymer‐modified zeolite than without the plasma coating, which may facilitate regeneration. Both indications make the amine plasma polymer‐based zeolite adsorbent a good candidate for CO2 adsorption and separation. [ABSTRACT FROM AUTHOR]

Mars has a special carbon dioxide environment. The surface and atmosphere of Mars contain a large amount of solid and gaseous carbon dioxide, which makes the in‐situ resource utilization of Martian carbon dioxide attract widespread attention. The conversion of carbon dioxide into fuel or high value‐added products through electrical discharge has become a research focus, in which numerical simulation is one of the important means to explain the experimental phenomenon and the mechanism. Therefore, a one‐dimensional fluid model was established in this paper to simulate the discharge and conversion of carbon dioxide under simulated Martian atmospheric pressure. The discharge mode, particle distribution, and discharge mechanism were studied by considering CO2 vibrational states and vibration relaxation reaction in the model. The results show that the discharge mode is glow discharge with an obvious cathode fall region, negative glow space, and positive column. The density of the four discharge products, C, O2, CO, and O, shows a step‐up trend, showing a significant cumulative effect, and the peak values appear near both electrodes. The density of vibrational states of CO2 molecule, which is highest in the neutral products, increases during the discharge stage and decreases after the discharge is extinguished. The temporal and spatial distribution of reaction rates shows that vibrational excitation, electronic excitation, and vibrational relaxation reactions dominate the loss and formation of CO2. The density of ground‐state CO2 decreases obviously in the discharge stage, and the minimum density appears near the instantaneous cathode. After the discharge is extinguished, the CO2 near the instantaneous cathode increases gradually. [ABSTRACT FROM AUTHOR]

This paper gives an overview of our plasma chemistry modeling for CO2 and CH4 conversion in a dielectric barrier discharge (DBD) and microwave (MW) plasma. We focus on pure CO2 splitting and pure CH4 reforming, as well as mixtures of CO2/CH4, CH4/O2, and CO2/H2O. We show calculation results for the conversion, energy efficiency, and product formation, in comparison with experiments where possible. We also present the underlying chemical reaction pathways, to explain the observed trends. For pure CO2, a comparison is made between a DBD and MW plasma, illustrating that the higher energy efficiency of the latter is attributed to the more important role of the vibrational levels. [ABSTRACT FROM AUTHOR]

This paper demonstrates that the CO2 conversion in a dielectric barrier discharge rises drastically upon addition of Ar or He, and the effect is more pronounced for Ar than for He. The effective CO2 conversion, on the other hand, drops upon addition of Ar or He, which is logical due to the lower CO2 content in the gas mixture, and the same is true for the energy efficiency, because a considerable fraction of the energy is then consumed into ionization/excitation of Ar or He atoms. The higher absolute CO2 conversion upon addition of Ar or He can be explained by studying in detail the Lissajous plots and the current profiles. The breakdown voltage is lower in the CO2/Ar and CO2/He mixtures, and the discharge gap is more filled with plasma, which enhances the possibility for CO2 conversion. The rates of electron impact excitation-dissociation of CO2, estimated from the electron densities and mean electron energies, are indeed higher in the CO2/Ar and (to a lower extent) in the CO2/He mixtures, compared to the pure CO2 plasma. Moreover, charge transfer between Ar+ or Ar2+ ions and CO2, followed by electron-ion dissociative recombination of the CO2+ ions, might also contribute to, or even be dominant for the CO2 dissociation. All these effects can explain the higher CO2 conversion, especially upon addition of Ar, but also upon addition of He. [ABSTRACT FROM AUTHOR]