Ordered Mesoporous Pd-La/Al2o3 Catalysts for Enhanced Methane Combustion

A series of ordered mesoporous Pd-M-Al (M = Mg, Ni, Y, La, and Ce) oxide catalysts with a fixed Pd content were prepared, and the effect of the promoters, viz., Mg, Ni, Y, La, and Ce on the catalytic performances was investigated for the catalytic combustion of methane. The fresh and used samples were characterized using multiple techniques, including high-angle annular dark field scanning transmission electron microscopy and 27Al magic angle spinning nuclear magnetic resonance spectroscopy. The results revealed that the addition of promoters has little effect on the morphology of the ordered mesoporous Al2O3 framework and Al3+ coordination environments. Among the catalysts, the ordered mesoporous 1%Pd-La/Al2O3 catalyst showed an excellent activity with a T90 of 420 °C and catalytic stability without notable deactivation for 2000 min, as compared with the 1%Pd/Al2O3 catalyst without the promoter. The improved catalytic performance is mainly related to the stabilization of PdO by La2O3 in the confined mesoporous skeleton of the catalyst