Advancing CO₂ to CO conversion: Detailed impact analysis of atmospheric molecules in an ultrashort pulse laser filament plasma reactor

Capturing carbon dioxide (CO 2 ) and transforming it into valuable fuels offers a dual benefit: the potential to reduce atmospheric CO 2 levels and decrease our dependency on fossil fuels. Plasma‐assisted CO 2 to carbon monoxide (CO) conversion stands out within the various CO 2 recycling methods, with research primarily emphasizing its energy efficiency and conversion efficacy. However, investigations of CO 2 conversion under real air conditions are relatively scarce, and the effects of the other atmospheric molecules on the CO 2 conversion process require further exploration. We have induced plasma chemical reactions by generating ultrashort pulse laser filaments inside a sealed‐off cavity with variable air pressures. Simultaneously, we applied mid‐infrared laser absorption spectroscopy to monitor the time evolution of the reaction products. The peak CO 2 ‐to‐CO conversion ratio was achieved at an air pressure of 8000 Pa, which resulted in a CO concentration of 82 ppm. The experimental results suggested that nitrogen (N 2 ) plays a promoting role in CO 2 ‐to‐CO conversion, while the presence of oxygen (O 2 ) seems to hinder the process. The hydroxyl radical (OH) arising from water molecules (H 2 O) limits the accumulation of CO at lower air pressures. However, at higher air pressures, the reduced OH radical concentration shows negligible impact on the CO 2 ‐to‐CO conversion ratios. In addition, the study revealed that atmospheric plasmas produce a high concentration of hydrogen cyanide (HCN), which is directly proportional to the levels of ambient humidity. This research contributes to the development of strategies to mitigate the production of harmful gases like HCN in CO 2 conversion, thereby promoting the ecofriendly conversion of atmospheric CO 2 .