Optical Emission Spectroscopy of CO2 Plasma Produced by CCP-Type Discharge

Abstract

This study investigates the decomposition of carbon dioxide (CO₂) using capacitively coupled plasma (CCP) technology. CO_2, a primary greenhouse gas, is decomposed into valuable products like carbon monoxide (CO) through plasma technology, a promising possibility for CO₂ reduction due to its efficiency and low energy consumption. The experiment systematically examines the decomposition of  CO₂ and its interaction with Argon. In-situ optical emission spectroscopy (OES) monitors the reaction while plasma temperature is assessed to understand the decomposition behavior of CO₂. Varying ratios of Ar are introduced into the plasma to explore their effects on CO₂ decomposition. The effects of discharge power and different working pressures on CO₂ decomposition were analyzed to provide insights into the process within CCP plasma. The results indicate that the introduction of a small amount of Ar, which is 20% of Ar and 80% of CO_2, shows that adding a small amount of Ar enhances CO₂ dissociation by 10%. A discharge power of 500W was identified as the most effective discharge power to dissociate the CO_2, and the working pressure of 200mTorr produced the most stable plasma discharge compared with other working pressures. Electron temperature (T_e) confirmed the impact of gas composition on plasma characteristics, as T_e increased steadily and allowing electrons to gain more energy sustained a higher temperature to dissociate CO₂. Hence, these findings contributed to the optimization of CO₂ conversion processes using non-thermal plasma technology for reducing greenhouse gas emissions.