Low-temperature combustion of methane using PdO/Al2O3 catalyst: Influence of crystalline phase of Al2O3 support

Palladium oxide (PdO) catalysts supported on various alumina supports (θ-, δ-, κ-, η-, and γ-Al2O3) were prepared and the effect of the crystalline phases of the supports on the catalytic performance in methane combustion was investigated. Among the catalysts examined, the PdO/θ-Al2O3 catalyst, which showed the lowest reduction temperature in the temperature-programmed reduction of methane and the highest oxygen capacity in methane pulse experiments, exhibited the highest CH4 conversion and stability for methane combustion. However, all the catalysts were deactivated because of the growth of PdO particles and strong adsorption of water vapor.