Glow Discharge With Hollow Electrodes for High‐Efficiency CO ₂ Decomposition

ABSTRACT Plasma technology can convert the greenhouse gas CO 2 into usable resources (CO, O 2 , methanol, ethanol) by directly decomposing it or converting it together with CH 4 , H 2 O, which is promising for a wide range of applications. In this study, a hollow cathode structure was designed to facilitate CO 2 passage and sustain a glow discharge mode. The plasma generated by direct current glow discharge at low pressure effectively decomposes CO 2 into CO and O 2 . The influence of parameters such as electrode spacing, electrode material, and discharge power on the efficiency of CO 2 decomposition was examined in the pressure range of 1‐12 kPa. The results demonstrated a CO 2 conversion rate of up to 31% and an energy efficiency exceeding 3.5% at an operating pressure of 1 kPa and a current of 80 mA. Electrode gap and gas flow direction have little effect on the CO 2 conversion. CO 2 conversion takes place mainly in the cathode layer. The CO 2 decomposition process under various conditions was analyzed by assessing electrical and spectral properties. Additionally, the impact of intermediate products on the formation of carbon deposition were investigated through SEM and EDS results, providing insights into the CO 2 reaction mechanism. This study also provides some ideas for the optimization of reactor design for CO 2 conversion.