Generation and migration of CO in CO₂ DBD glow plasma under Martian pressure

Abstract

Dielectric barrier discharge (DBD) plasma is a potential tool in the field of in situ CO2 conversion with the low‐pressure environment of Mars. CO is an important intermediate product in the conversion process of CO2. Understanding the pathways and dynamics that govern the generation of CO in CO2 plasmas establishes the foundation for effective regulation. In this work, parallel‐plate DBD structure was employed in our experiment and one‐dimensional fluid simulation model. The findings indicate that CO primarily originates at the boundary of the cathode potential fall region, and it subsequently migrates toward the surface of instantaneous cathode where it accumulates. The thickness of CO‐enriched region is approximately 0.8 mm. During this process, CO migration speed reaches about 2000 m/s. It is worth noting that surface reactions at the instantaneous cathode and anode surfaces contribute only 0.24% to CO generation, in contrast to the predominant influence of impact dissociation reaction between CO2 and electrons (e + CO2 → 2e + CO + O+) at 53.21%, and two‐body decomposition reaction between O+ and CO2 (O+ + CO2 → O +2 + CO) at 35.88%. Finally, the primary factors influencing the migration of CO from production sites to enrichment regions are determined to be particle collisions and momentum exchange between ions and CO, followed by electro‐hydro dynamics force, while dielectrophoresis forces have minimal effect.