Radio-Frequency Non-Thermal Plasma for CO₂ Dissociation and NOx Formation for Ammonia Synthesis

Non-thermal plasma provides a pathway to drive dissociation and synthesis reactions at room temperature and atmospheric pressure, offering a potential for more sustainable and diverse production. Two applications explored in this work are CO₂ conversion to CO and nitrogen oxide formation as a preliminary step towards ammonia synthesis, both investigated in an argon-based radio-frequency (RF) capacitively coupled plasma (CCP). This thesis investigates the effects of the variation in generator power, gas composition and total flow rate, and evaluates their influence on the relevant dissociation pathways of CO₂ dissociation and nitrogen oxide formation. Analysis is conducted using Fourier-transform infrared (FTIR) spectroscopy, with product concentrations calculated from absorption spectra. Findings include that lower flow rates show an increase in the production of CO density and yield, but a trade off with energy efficiency. The maximum NOx density and yield were observed at an O₂/N₂ ratio of approximately 8:4, indicating that this composition provides the most favourable conditions for NOx formation. Ultimately, the primary objective of this thesis is to support more effective design and operation of radio-frequency driven low-temperature plasma systems. This will be accomplished through the controlled variation of experimental parameters to analyse their impact on dissociation and formation mechanisms. This thesis provides actionable insights for both experimental practice and analytical interpretation for targeted goals.