CeO₂ had a lower activity for hydrocarbon oxidation according to the correlation between the rate of hydrocarbon oxidation and metal oxygen bond strength (volcano plot). However, the CH₄ combustion activity of the nanosized CeO₂ supported on barium hexaaluminates was so high that the temperature for 10% conversion was comparable with that of noble metal oxide catalysts. Such a result has attracted considerable attention due to effect of preparation on the structure and combustion activity of CeO₂^- containing catalysts. In present work, BaMAl₁₁O_19-α (M=Mn, Co, Ce) catalysts were prepared by reverse microemulsion. Effect of M on phase composition, specific surface area and CH₄ combustion activity was investigated. β-Al₂O₃ and CeO₂ are the major phase in the BaMnAl₁₁O_19-α and BaCeAl₁₁O_19-α catalysts, respectively, while BaCoAl₁₁O_19-α catalyst consists of γ-Al₂O₃ and α-Al₂O₃ phase. The BaCeAl₁₁O_19-α has the highest surface area among the three catalysts, but its combustion activity is lower than that of the BaMAl₁₁O_19-α catalyst. On the basis of the results from BaMAl₁₁O_19-α (M=Mn, Co, Ce) catalysts, CeO₂/BaMAl₁₁O_19-α catalysts were prepared. It not only has a higher specific area but also has a higher activity for methane combustion. The results from the 100 h activity test showed that CeO₂/BaMAl₁₁O_19-α might be a candidate for catalytic gas turbine combustor.

Key words: methane, catalytic combustion, reverse microemulsion, CeO₂