Dielectric barrier discharge plasma-assisted CO₂ reduction with waste plastic pyrolysis gas

Converting CO₂ into valuable chemicals with low cost is significantly attractive for building a carbon-neutral society. Compared to the high energy-consuming CO₂ chemical reduction methods, this study proposed a plasma-assisted waste conversion process at room temperature and atmospheric pressure. A coaxial dielectric barrier discharge (DBD) reactor was utilized for plasma-assisted CO₂ reduction. Ethylene (C₂H₄), simulating waste plastic pyrolysis gas, was introduced into the reactor under ambient conditions. The effects of key parameters - CO₂/C₂H₄ molar ratio (4:1-1:4), plasma voltage (20-50 V), and feed flow rate (50-500 mL/min) - were systematically investigated to optimize the production of oxygen-containing liquid hydrocarbons. Product composition was analyzed through GC-MS, revealing dominant alcohols (e.g. 1-butanol, 26.81%) and acids (e.g. acetic acid, 23.92%). Results show CO₂ can be successfully reduced to liquid hydrocarbon products, and the main effect on product distributions is the CO₂/C₂H₄ molar ratio. The selectivity of typical products (1-butanol l and acetic acid) were theoretically discussed through DFT analysis, enhancing the understanding of the reaction process involved in the hydrogenation reduction of aldehydes to alcohols and the oxidation of aldehydes to acids. This study represents a novel approach for CO₂ reduction by utilizing waste plastic pyrolysis.