Temperature-Dependent Kinetics of Plasma-Based CO2 Conversion: Interplay of Electron-Driven and Thermal-Driven Chemistry.

The transformation of CO2 into chemical building blocks for various industries is considered a key technology in a net-zero energy future. To realize this, plasma discharges are one of the most promising approaches thanks to their electron-driven reactions and high operational flexibility. Most studies focused on room-temperature and vibrationally-excited discharges, however, lately, the importance of thermal reactions is considered. Therefore, we developed a temperature-dependent plasma-chemical reaction mechanism to investigate the temperature dependence of plasma-based CO2 conversion. Here, we present the various effects of thermally-driven reactions on the CO2 conversion as a function of the gas temperature and specific energy input. Our analysis pinpointed the key reactions controlling the plasma-based CO2 conversion, shifting from an electron-driven to a thermal-driven regime. Additionally, we used the mechanism to verify the theoretical upper boundary of the process' energy efficiency, and discussed how our findings could lead to the further development and optimization of plasma discharges for efficient CO₂ conversion in the future.