Direct Conversion of Carbon Dioxide to Methane over Ceria‐ and Alumina‐Supported Nickel Catalysts for Biogas Valorization

Abstract Direct methanation of CO 2 over ceria‐ and alumina‐supported nickel catalysts in the feed stream containing methane and traces of H 2 S is reported. Stability tests for 20 h at 350 and 600 °C with a packed‐bed reactor showed high resistance of the catalysts to sintering processes. Higher conversion at 350 °C was observed for ceria supported nickel catalyst. Thermodynamic analysis indicated that CO 2 contained in biogas can be converted to methane without carbon formation under specific reaction conditions. An introduction of CH 4 to CO 2 −H 2 feed stream led to the decrease in CO 2 conversion and CH 4 selectivity. An introduction of the trace amounts of H 2 S into the feed stream led to the fast drop of CO 2 conversion and CH 4 selectivity; higher durability (20 %) was observed for Al 2 O 3 than CeO 2 supported catalysts. An improved performance of catalysts coated onto high‐pressure microchannel microreactors for the direct CO 2 methanation reaction applying model biogas mixture was demonstrated.