Synthesis of ethane and ethylene from methane and carbon dioxide over praseodymium oxide catalysts

Catalytic effectiveness for the synthesis of ethane and ethylene from methane and carbon dioxide has been examined mainly at 1123 K over 14 lanthanide oxides. Praseodymium (Pr) and terbium oxides show high yield and high selectivity of C-2 hydrocarbons among lanthanide oxides. The catalytic performances of Pr oxides are influenced by the preparation method; a commercial Pr oxide prepared from the oxalate shows the highest C-2 selectivity of about 50%, and the stable performance for 20 h. Higher partial pressures of CO2 and CH4 are favorable for C-2 formation over the oxide catalyst. Reaction mechanisms over Pr oxides are discussed in terms of a redox mechanism involving the unstable lattice oxygen.