Hydrogen-driven enhancement of CO2 splitting in a non-thermal plasma reactor for sustainable carbon utilization

As the global carbon crisis worsens, we need the technology which can evolve from capturing carbon to efficiently using it. Dielectric barrier discharge (DBD) systems under mild conditions, a type of non-thermal plasma (NTP) reactor, provide a promising electrified route to CO 2 splitting. However, their large-scale application is curtailed due to their low energy efficiency and modest CO 2 conversion. The study reveals that the radical-assisted dissociation channels are activated by the controlled addition of H 2 (4-15 vol%) to CO 2 feed. By intentionally adjusting discharge power (10-40 W) and residence time (6-26 s), our study revealed that H 2 co-feeding helps in the formation of H ⋅ and OH ⋅ . This, in turn reduces the activation barrier of CO 2 cleavage and influences the distribution of vibrational excitation and electron energy. Energy efficiency has improved by around 38%. A rise in H 2 concentration lowers total conversion of CO 2 due to rise in radical recombination. Results of the BOLSIG + simulation indicate that the values of the electron temperature and the reduced electric field (E/N) experience distinct shifts which help rationalize the dual behavior of Hydrogen as a reaction enhancer and quencher. These results provide design principles for next-generation electrified reactors with optimised co-feeding and power-modulation strategies, establishing hydrogen-assisted plasma catalysis as a strategic path towards energy-efficient CO2 utilisation.