Easing of frequency gaps in carbon monoxide formation with argon diluents in carbon dioxide dielectric barrier discharge

The transformation of carbon dioxide (CO2) to carbon monoxide (CO) employing atmospheric pressure dielectric barrier discharge (DBD) cold plasma in Ar mixed CO2 systems is reported. This work is aimed to re-utilize CO2 in the form of CO, which is well accepted as industrial gas and also has many manufacturing applications. Under the study, Ar mixed CO2 gas stream is used to investigate the effective conditions for achieving low to high CO yields using a coaxial cylindrical single dielectric (SD) (consisting of one Pyrex and one bare copper surfaces) DBD reactor. The CO as DBD outlet product and leftover CO2 are analyzed online with gas chromatograph-flame ionization detector after their successive separation with a suitable GC column and methanation using Ni-catalyzed methaniser. The experiments are carried out at a fixed gas flow of 110 ml/min (translating gas residence time (GRT) = 3.2 s) with applied electric field and working frequency variations. The resulting contour plots (generated using electric fields, frequency and CO yields) indicate that the mixing of 90% Ar in CO2 system exhibits substantial reduction of frequency gaps in CO formation. Nevertheless, the frequency gaps are more prominent in low/negligible Ar mixed CO2 systems. It is also noticed that the lower electric fields are adequate to generate CO in Ar mixed CO2 systems in contrast to pristine CO2 system. Both Ar mixing as well as electric field inputs are responsible to easy/lessen the frequency gaps.