The CO2 reforming of CH4 to synthesis gas is performed in a dielectric barrier discharge (DBD) plasma coupled with g-C3N4, g-C3N4/TiO2, g-C3N4/ZnO and g-C3N4/mixed oxide (2.5 wt% ZnO and 2.5 wt% TiO2) catalysts. For CH4 and CO2 gases, the highest conversion is obtained with 5 wt% TiO2 + g-C3N4 and 5 wt% ZnO + g-C3N4, respectively. The g-C3N4 and 5 wt% TiO2 + g-C3N4 catalysts shows poor selectivity towards H2 and CO formation. Whereas, 5 wt% ZnO + g-C3N4 exhibits the highest H2 and CO selectivity. However, with increasing SIE the CO selectivity decreases over 5 wt% ZnO + g-C3N4. The selectivity towards H2 and CO are found to be optimal over 5 wt% MO (1:1) + g-C3N4 and the combination of TiO2 + ZnO coupled with g-C3N4 significantly improves the carbon balance. This optimum performance by 5 wt% MO (1:1) + g-C3N4 in providing the best carbon balance is due to the combination of electronic and acid-base characteristics of the catalysts. The generation of various active species is evidenced by emission spectroscopic study. © 2019 Elsevier Ltd