The influence of power and frequency on the filamentary behavior of a flowing DBD-application to the splitting of CO2

TL;DR

This study investigates how power and frequency affect filamentary microdischarges in a flowing DBD used for CO2 splitting, revealing that charge delivery and filament regime influence conversion efficiency.

Contribution

It provides new insights into the role of frequency and power in filamentary behavior and CO2 conversion in flowing dielectric barrier discharges.

Findings

Conversion depends mainly on charge delivered, not plasma voltage.

Lower frequencies yield better CO2 conversion with less filamentary discharges.

Filamentary regime and effective plasma voltage are key factors in efficiency.

Abstract

In this experimental study, a flowing dielectric barrier discharge operating at atmospheric pressure is used for the splitting of CO2 into O2 and CO. The influence of the applied frequency and plasma power on the microdischarge properties is investigated to understand their role on the CO2 conversion. Electrical measurements are carried out to explain the conversion trends and to characterize the microdischarges through their number, their lifetime, their intensity and the induced electrical charge. Their influence on the gas and electrode temperatures is also evidenced through optical emission spectroscopy and infrared imaging. It is shown that, in our configuration, the conversion depends mostly on the charge delivered in the plasma and not on the effective plasma voltage when the applied power is modified. Similarly, at constant total current, a better conversion is observed at low frequencies, where a less filamentary discharge regime with a higher effective plasma voltage than that at a higher frequency is obtained.