The CO2 Conversion in a DBD Plasma: A 1D Synergistic Catalysis Model

Abstract

Objective: Plasma catalysis is regarded as a promising technology in mitigating atmospheric CO2, but there is still a gap between industrial demand and current efficiency. This paper aimed to investigate the synergistic effect between vibrational states and catalyst surfaces in plasma catalysis, and to offer a theoretical guide on how to maximize the effectiveness of the synergistic effect in a more energy-efficient way. Methods: A novel 1D dielectric barrier discharge plasma catalysis model has been developed. The Arrhenius equations were used to solve the surface catalytic chemistry. The influence of CO2 vibrational excitation on surface reaction rates were expressed in the framework of the theoretical-informational approach. Results: The simulation suggested that a lower electron temperature fosters vibrational excitation, while a higher electron temperature promotes electronic excitation, therefore, the CO2 conversion rate and energy efficiency were difficult to be improved simultaneously. Furthermore, our model elucidates the pivotal role of catalysts in achieving efficient decomposition of vibrationally excited CO2 (CO2v). However, under conditions of low vibrational density, this synergistic effect fails to yield substantial improvements in catalytic efficiency under low vibrational density conditions. Conclusion: By increasing the pulse voltage, using narrow pulses with rapid rise times, implementing rapid cooling techniques and enlarging the surface catalytic area, the concentrations of CO2v can be augmented. Consequently, the dissociation rate via the V-V process and surface processes can both be enhanced, thereby potentially enabling simultaneous improvements in the CO2 conversion rate and energy efficiency.