Plasma-Catalytic CO2Hydrogenation at Low Temperatures

Abstract

A coaxial packed-bed dielectric barrier discharge (DBD) reactor has been developed for plasma-catalytic CO2 hydrogenation at low temperatures and atmospheric pressure. Reverse water-gas shift reaction and carbon dioxide methanation have been found dominant in the plasma CO2 hydrogenation process. The results show that the H2/CO2 molar ratio significantly affects the CO2 conversion and the yield of CO and CH4. The effect of different $\gamma $ -Al2O3 supported metal catalysts (Cu/ $\gamma $ -Al2O3, Mn/ $\gamma $ -Al2O3, and Cu–Mn/ $\gamma $ -Al2O3) on the performance of the CO2 hydrogenation has been investigated. Compared with the plasma CO2 hydrogenation without a catalyst, the combination of plasma with these catalysts enhances the conversion of CO2 by 6.7%–36%. The Mn/ $\gamma $ -Al2O3 catalyst shows the best catalytic activity for CO production, followed by the Cu–Mn/ $\gamma $ -Al2O3 and Cu/ $\gamma $ -Al2O3 catalysts. The presence of the Mn/ $\gamma $ -Al2O3 catalyst in the plasma process significantly increases the yield of CO by 114%, compared with the plasma reaction in the absence of a catalyst. In addition, we find that combining plasma with the Mn/ $\gamma $ -Al2O3 catalyst significantly enhances the energy efficiency of CO production by 116%, whereas packing the Cu/ $\gamma $ -Al2O3 catalyst into the DBD reactor only increases the energy efficiency of CO production by 52%.