Nonthermal plasma-assisted catalytic methanation of CO and CO2 over nickel-loaded alumina

Abstract

Nonthermal dielectric barrier discharge plasma was applied for the heterogeneously catalyzed methanation of CO and CO2 over alumina-supported catalysts at 180-320oC and atmospheric pressure. The characteristics of methane synthesis under plasma discharge conditions were investigated with several catalysts, including Al2O3, TiO2/Al2O3, Ni/Al2O3 and Ni-TiO2/Al2O3. The results obtained with Al2O3 or TiO2/Al2O3 catalysts indicated that either gas-phase reactions or photocatalysis induced by the plasma as well as the adsorption of carbon oxides on Al2O 3 hardly contribute to the methanation of CO and CO2. On the other hand, nickel-loaded catalysts like Ni/Al2O3 and Ni-TiO2/Al2O3 were found to be considerably affected by the plasma, resulting in enhanced methanation rate. It is believed that the nonthermal plasma created in the catalytic reactor can accelerate the rate-determining step by dissociating carbonoxygen bonds of carbon oxides adsorbed on the active sites of the catalysts. © 2011 WIT Press.