Generation of dielectric barrier discharge in high-pressure N₂ and CO₂ environments up to supercritical conditions

The generations of dielectric barrier discharge (DBD) in high-pressure nitrogen and carbon dioxide environments up to supercritical conditions with or without flow fields were performed. From the second positive system of nitrogen, the rotational temperature of N₂ was estimated to be approximately 400 K under a supercritical N₂ condition (4 MPa and 313 K). On the other hand, from emission spectra of DBD in a high-pressure CO₂ environment (1-8 MPa), C₂ and O spectra were remarkable in intensity instead of CO, CO⁺, CO₂ and CO₂⁺ spectra that were remarkable at atmospheric pressure. Furthermore, porous carbon film synthesis by DBD under a supercritical CO₂ condition (7. 5 MPa and 305 K) was also identified by scanning electron microscopy observation.