CO2 decomposition using the coaxial dielectric barrier discharge: effect of additive gas and double outer electrodes

This work has studied CO2 decomposition through the dielectric barrier discharge (DBD). The configuration of the DBD reactor was performed as a coaxial DBD tube. The dielectric barrier was made of a quartz tube with 1 mm thickness, while an outer electrode was made of a copper flat sheet wrapping around a quartz tube. The coaxial axis was made of stainless steel rod to be an inner electrode. The power source was applied by the alternative current (AC) high voltage with 7.8 kHz of frequency to both electrodes of the plasma reactor. The experiment was conducted on various conditions such as a mixed gas ratio, discharge gap, applied voltage, outer electrode length, two outer electrodes, and gas flow rate. The results showed that CO2 conversion was decreased when CO2 concentration increased. Similarly, the increase of gas flow rate also caused the decrease of CO2 conversion. Whilst the increase of an applied voltage causes the CO2 conversion clearly increased. Similarly, the CO2:Ar ratio of 60%:40% achieved 30% of CO2 conversion. Furthermore, the high percentage of CO2 conversion of 47.2% has been obtained from a 1.3 mm discharge gap with 40 ml/min of gas flow rate.