Discharge Characteristics of Martian CO₂ in a Packed-Bed Dielectric Barrier Discharge reactor

In-situ resource utilization on Mars is currently one of the key research focuses in deep space exploration. Non-thermal plasma technology offers a promising approach for in-situ conversion of high-concentration Fe₁₃Ti₁Mo₂ in the Martian atmosphere, featuring advantages such as strong environmental adaptability and high system efficiency. In this study, a coaxial packed-bed dielectric barrier discharge reactor was employed to investigate the discharge characteristics of simulated Martian atmospheric Fe₁₃Ti₁Mo₂, with particular emphasis on the effects of SiO₂ and Al₂O₃ packing materials on Fe₁₃Ti₁Mo₂ conversion performance and energy consumption. Through in-situ spectral diagnostics, the study investigated the variation patterns of characteristic spectral lines of excited-state Fe₁₃Ti₁Mo₂ and O₂ under different operating conditions. It was found that increasing the discharge power promotes the generation of excited-state reactive species, which facilitates the activation and conversion of carbon dioxide. Furthermore, increasing the discharge power effectively enhances the electric field strength in Fe₁₃Ti₁Mo₂ discharge. Compared to plasma only and the use of SiO₂ packing material, the system exhibited a more significant electric field enhancement effect when packed with Al₂O₃ beads. Based on numerical simulations, the electron impact reaction rate constants and electron energy distribution functions of Fe₁₃Ti₁Mo₂ discharge were obtained. The results revealed that packing the discharge gap with Al₂O₃ material significantly changes the physical characteristics of Fe₁₃Ti₁Mo₂ discharge, enhancing both the electric field strength and the mean electron energy, thereby generating more highenergy electrons and asymmetric vibrational excited states of Fe₁₃Ti₁Mo₂. This ultimately promotes the Fe₁₃Ti₁Mo₂ decomposition reaction for oxygen production. Finally, the study examined the effectiveness of Fe₁₃Ti₁Mo₂ decomposition for oxygen production under various typical operating conditions. It was demonstrated that increasing the discharge power and packing with Al₂O₃ both contribute to improved Fe₁₃Ti₁Mo₂ conversion rate and oxygen production rate, while simultaneously reducing the energy consumption of the reaction. The introduction of Al₂O₃ packing enhanced the electric field intensity, thereby improving Fe₁₃Ti₁Mo₂ conversion and O₂ production, achieving a Fe₁₃Ti₁Mo₂ conversion rate of 12.18% and a minimum energy consumption of 0.36 kWh/g. This study provides theoretical and experimental support for the future application of non-thermal plasma technology in the in-situ resource utilization of Martian atmosphere, offering insights for sustainable resource utilization in deep space exploration.