Combustion of a trace amount of CH4 in the presence of water vapor over ZrO2-supported Pd catalysts

Combustion of a trace amount of CH4 over Pd catalysts supported on calcined ZrO2 was examined under nearly exhaust gas conditions where the temperatur e is not so high and water vapor coexists. High catalytic activity was obta ined with ZrO2 support calcined at 1073 and 1273 K. The durability test at 673 K for 100 h revealed that the activity of these catalysts hardly decrea sed, while that of the Pd catalysts supported on calcined Al2O3 were much d ecreased in the course of time. These results demonstrated the advantages o f ZrO2 as a support for Pd catalysts in the present reaction.