Probing the impact of material properties of core-shell SiO2@TiO2 spheres on the plasma-catalytic CO2 dissociation using a packed bed DBD plasma reactor

Characterizing the stability of ultra-thin metal oxide catalyst films in non-thermal plasma CO2 reduction reactions

The use of metal oxide catalysts to enhance plasma CO2 reduction has seen significant recent development towards processes to reduce greenhouse gas emissions and produce renewable chemical feedstocks. While plasma reactors are effective at producing the intended chemical transformations, the conditions can result in catalyst degradation. Atomic layer deposition (ALD) can be used to synthesize complex, hierarchically structured metal oxide plasma catalysts that, while active for plasma CO2 reduction, are potentially vulnerable to degradation due to their high surface area and nanoscopic thickness. In this work, we characterized the effects of extended non-thermal, glow discharge plasma exposure on ALD synthesized, ultra-thin film (<30 nm) TiO2 and ZnO catalysts. We used X-ray diffraction, reflectivity, and spectroscopy to compare films exposed to a CO2 plasma to ones exposed to an Ar plasma and to ones annealed in air. We found that the CO2 plasma exposure generated some surface reduction in TiO2 and increased surface roughening by a small amount, but did not initiate any phase changes or crystallite growth. The results suggest that ALD-deposited metal oxide films are robust to low pressure CO2 plasma exposure and are suitable as catalysts or catalyst supports in extended reactions.

Recent advances in energy efficiency optimization methods for plasma CO2 conversion

Efforts to develop efficient methods for converting carbon dioxide (CO2) have drawn mounting interest due to incremental concerns over carbon emissions. Non-thermal plasma (NTP) technology has shown promise in this regard by producing numerous reactive substances at relatively low temperatures. However, an analysis of relevant literature reveals an underwhelming level of overall energy efficiency for this technology and an insufficient level of attention being paid to it. It is crucial to put forward more effective energy-saving schemes based on a comprehensive analysis of past research results to promote sustained development. This review highlights the latest advances in pertinent energy efficiency optimization studies and outlines state-of-the-art methods. In terms of energy efficiency optimization for plasma CO2 conversion, a comparison is made among different research results in four aspects as follows. Specifically, this study analyzes reactor structure optimization in terms of discharge characteristic, flow field, and plasma contact area; discusses pathways of heat transfer optimization to suppress the competing reaction; and explores catalyst optimization in terms of active sites, calcination temperature, and product selectivity; examines the potential of utilizing solar energy for clean energy applications. The analysis of energy efficiency data indicates an overall improvement when the aforementioned optimization measures are applied, which is essential to validate the effectiveness of each method. Finally, this paper discusses the potential difficulties and future research areas of NTP technology. Urgent further research is imperative on energy efficiency optimization methods for potential large-scale industrial applications in the future.

Carbon Dioxide Conversion Synergistically Activated by Dielectric Barrier Discharge Plasma and the CsPbBr3@TiO2 Photocatalyst

Carbon dioxide utilization activated by the integration of plasma and photocatalyst is a promising approach to achieve the mitigation of the greenhouse effect. In this paper, for the first time, the dielectric barrier discharge (DBD) plasma and halide perovskite photocatalysts were synergistically used to facilitate the carbon dioxide conversion. After introducing the photocatalyst into the plasma reactor, the plasma discharge characteristics were improved by the photocatalyst while the active photons, electrons, and vibrationally excited molecules in plasma also enhanced the photocatalytic activity of the photocatalyst. Compared with pure CsPbBr₃ and Al₂O₃, the CsPbBr₃@TiO₂ with the best photocatalytic activity also exhibited the best performance in plasma. The carbon dioxide conversion rate of the DBD plasma filled with CsPbBr₃@TiO₂ was found to be 29.6% higher than the sum of sole plasma and photocatalysis, illustrating the achievement of the synergistic effect between the plasma and photocatalyst. This work brings up new opportunities for efficient large-scale conversion and utilization of carbon dioxide by the coupling of nonthermal plasma and photocatalysis.