A zero-dimensional model for atmospheric non-thermal plasma CO 2 hydrogenation: insights into the reaction mechanism

• Published in: Japanese Journal of Applied Physics 2022-08, Vol.61 (8), p.86001
• Main Authors: Chen, Yeli, Peng, Yi, Qian, Muyang, Liu, Sanqiu, Zhang, Jialiang, Wang, Dezhen
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/ac79eb

Recently, plasma CO 2 hydrogenation to generate valuable products (e.g. CO and CH 4 , hydrocarbons and oxygenates) has attracted more and more attention. The conversion of carbon dioxide (CO 2 ) and hydrogen (H 2 ) in an atmospheric non-thermal plasma was investigated by a zero-dimensional plasma kinetic model. This paper focuses on the effect of different feed gas composition ratios (H 2 /CO 2 volume ratio) on the plasma CO 2 hydrogenation reaction mechanisms. It is found that H 2 addition in plasma not only promotes CO 2 dissociation but also changes the plasma chemistry, which seems to significantly enhance the electron density and temperature. Besides, larger H 2 content in the H 2 /CO 2 mixture is beneficial to obtaining a higher number density of methanol, which is in good agreement with published experimental data. The temporal distributions of abundant radicals, ions and molecule densities are determined under a series of initial hydrogen content. Conversions of inlet H 2 /CO 2 and selections toward CO and CH 4 are calculated and presented. The primary reaction channels related to the production and destruction of CO, H, CH 2 O, CH 3 OH, CH 4 and H 2 O are determined. Finally, the underlying overall reaction mechanisms regarding the plasma CO 2 hydrogenation are analyzed in detail by the chemical reaction flow chart.