This paper reports on the study of repetitive nanosecond-pulsed discharge splitting of carbon dioxide (CO ₂ ) for the production of CO. Gas chromatography is used to analyze the composition of the reformed gas when CO ₂ is exposed to high-voltage (15 kV) very short (10 ns) electrical discharges that deposit as much as 0.4 mJ of energy at a rate of 30 kHz. Conversion rate and energy efficiency are obtained while the discharge pressure is varied between 2.4 and 5.1 atm. At the tested conditions, the maximum conversion rate and energy efficiency are found to be 7.3% and 11.5%, respectively. The energy efficiency drops slightly with increased pressure because of the decreased electric field and electron energy per molecule. An energy balance analysis of a set of CO ₂ plasma reactions reveals that the dominant dissociation pathway under these conditions passes through the excitation of CO ₂ (10.5 eV) followed by autodissociation into CO and O, which are often in excited states.

Emission measurements are carried out to study the quenching of excited electronic states of nitrogen, $\text{N}_2{}^{\ast }$ , in nanosecond pulsed discharges in atmospheric pressure air and nitrogen. The results reveal that ground state ${\text{N}}_2$ quenches ${\text{N}}_2\left(\text{C}\right)$ and ${\text{N}}_2\left(\text{B}\right)$ at rates less than dissociative quenching by ground state ${\text{O}}_2$ by a factor of 4 and 2.5, respectively. Kinetic simulations with the inferred quench rates indicate that the dissociative quenching of $\text{N}_2{}^{\ast }$ by ${\text{O}}_2$ is responsible for 82% of atomic oxygen production while electron-impact dissociation of ${\text{O}}_2$ is for 5% under these discharge conditions.