Nonthermal Plasma-Assisted Enhanced CO₂ Conversion over NiO_x/γ-Al₂O₃ Catalyst

Abstract

The utilization of the dielectric barrier discharge (DBD) plasma process presents a promising avenue for transforming carbon dioxide (CO 2 ) into valuable compounds. In this research, we explore the integration of DBD plasma with a NiO x /γ-Al 2 O 3 catalyst to amplify the efficiency and selectivity of the conversion of CO 2 into carbon monoxide (CO). A series of NiO xloaded on γ-Al 2 O 3 catalysts were synthesized through wet impregnation and employed in the DBD plasma reactor. The synergy between nonthermal plasma and NiO x /γ-Al 2 O 3 resulted in a significant enhancement in CO 2 conversion, particularly demonstrating a notable increase in the energy content of produced carbon monoxide (CO). Enhanced conversion rates and selectivities were observed. Notably, the NiO x /γ-Al 2 O 3 catalyst with a 15 wt % loading exhibited the highest CO 2 conversion of approximately ∼9% at an applied voltage of 22 kV, accompanied by an energy efficiency of 1.13 mmol kJ −1 . This study provides a comprehensive analysis of the impact of plasma catalyst coupling on CO 2 conversion into CO, showcasing the potential of hybrid DBD reactor systems for large-scale CO 2 conversion and contributing to sustainable and value-added fuel production. The superior performance of the hybridized system is attributed to enhanced charge deposition and modified gas-phase chemistry resulting from the integration of the catalyst. Furthermore, we employed BOLSIG+ software to calculate the mean electron energy and electron energy distribution function for different packing conditions, enhancing our understanding of the system's behavior and contributing valuable insights to the overall study.