Plasma-Catalytic CO2Hydrogenation at Low Temperatures

A coaxial packed-bed dielectric barrier discharge (DBD) reactor has been developed for plasma-catalytic CO2hydrogenation at low temperatures and atmospheric pressure. Reverse water-gas shift reaction and carbon dioxide methanation have been found dominant in the plasma CO2hydrogenation process. The results show that the H2/CO2molar ratio significantly affects the CO2conversion and the yield of CO and CH4. The effect of different γ-Al2O3supported metal catalysts (Cu/γ-Al2O3, Mn/γ-Al2O3, and Cu-Mn/γ-Al2O3) on the performance of the CO2hydrogenation has been investigated. Compared with the plasma CO2hydrogenation without a catalyst, the combination of plasma with these catalysts enhances the conversion of CO2by 6.7%-36%. The Mn/γ-Al2O3catalyst shows the best catalytic activity for CO production, followed by the Cu-Mn/γ-Al2O3and Cu/γ-Al2O3catalysts. The presence of the Mn/γ-Al2O3catalyst 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/γ-Al2O3catalyst significantly enhances the energy efficiency of CO production by 116%, whereas packing the Cu/γ-Al2O3catalyst into the DBD reactor only increases the energy efficiency of CO production by 52%.