Effect of Argon on CO2 Decomposition in Micro-Slit Sustained Glow Discharge Reactor

The microdischarge CO2 decomposition devices have the advantages of a simple structure and low energy consumption and thus have a very promising future in in-situ resource utilization technology for Mars missions. It was found that the addition of Ar increased the conversion rate of CO2 in a micro-slit sustained glow discharge reactor. The experimental results showed that the breakdown voltage of Ar was significantly lower than that of CO2 in the micro-slit discharge, which indicated that the discharge breakdown channel was more likely to be generated. Thus, the addition of Ar to CO2 resulted in a lower breakdown voltage, and the discharge energy could be more distributed for CO2 decomposition. Spectral intensity analyses showed that, for CO2/Ar mixture discharges, the presence of high-energy Ar excited states was clearly observed. With increasing discharge voltage, an increase in the light intensity of active components such as CO2+, O, and CO was observed. Combined with the discharge parameters and spectral characterization, it can be concluded that the metastable species of Ar exist and accumulate during the discharge, which contributes to the conversion of CO2.