Stability of kinetic parameters of Co3O4/CeO2 catalyzed methane combustion

The work assesses the effect of hydrothermal ageing on the kinetic parameters of lean methane combustion catalyzed by cobalt oxide supported on ceria. The reactions are performed at model conditions relevant to the exhaust of natural gas vehicles, that is, at temperatures between 200°C‐550°C with 0.05 mL/mL (5 vol%) and 0.10 mL/mL (10 vol%) of water in the feed, as well as in the dry feed. The addition of 0.05 mL/mL (5 vol%) of water results in a double decrease of the rate constant, which is not affected by further water increase to 0.10 mL/mL (10 vol%). The reactions in the dry and wet feeds show zero order to water and first order to methane; the activation energy of 73 kJ/mol is the same for all conditions for the supported and unsupported cobalt oxide catalysts. After 100 hours on stream, the supported catalyst shows the same methane conversion as the fresh catalyst. Fresh and aged supported cobalt oxide catalyst shows identical methane conversion in lean combustion.