Studies of electric and spectral characteristics of surface spark discharge in atmosphere of carbon dioxide. Conversion of CO2 and CO2:H2 to CO

Abstract

The results are presented from studies of the high-voltage pulse-periodic surface spark discharge propagating along the water-gas interface. In the case of CO2 or CO2:H2 mixture used as gaseous medium, the plasma-chemical conversion of CO2 to carbon monoxide CO was also studied. In the experiments, we used the generator with reservoir capacitor energy of 1.6 J, a voltage of 20 kV, and pulse duration of 2–3 μs. The average velocity was determined of the discharge propagation along the water surface in the CO2, CH4 and Ar atmospheres. It was shown that the leader velocities in the CO2 and CH4 atmospheres coincide, and they turned out to be 3–4 times lower than that in the Ar atmosphere. The integrated emission spectra are presented of the discharge in the CO2 atmosphere, in which the lines corresponding to CO2, CO, Hα, Hβ, and OI are distinguished. The electron concentration in the discharge channel was Ne = 1017 cm-1. The dynamics of conversion of CO2 to CO was traced at different energies inputted into the discharge. For the discharges in the atmospheres of CO2 and CO2:3H2 mixture, the degrees of conversion were 24 and 61%, respectively. And in the quasi-linear stage, the energy efficiencies of conversion were ∽13 and ∽6 eV per molecule for the CO2 and CO2:3H2 atmospheres, respectively.