Pd/SmMn2O5 catalyst for methane combustion: efficient lattice oxygen and strong metal-support interaction.

Manganese-based mullite-type and perovskite-type mixed oxides were prepared by sol–gel method, and then palladium was loaded onto the mixed oxides by wet impregnation method. The catalytic performance for methane combustion, the influence of the supports, and the interaction between noble metal and the mixed oxides were investigated via experiments and theoretical calculations. The Pd/SmMn2O5 catalyst exhibited superior low-temperature catalytic activity for methane combustion (T50 = 328 °C), which was superior to the Pd/perovskites catalysts and even better than Pd/Al2O3 catalyst. It was ascribed to the abundant labile surface lattice oxygen species with high mobility and the uniformly dispersed Pd species on SmMn2O5, as revealed by TEM, CO-chemisorption, H2-TPR and XPS. DFT calculations verified the significant metal-support interaction via electron transfer between Pd and SmMn2O5, which further activated the lattice oxygen and improved the catalytic performance. It demonstrates the prospect of utilizing SmMn2O5 mullite to optimize the typical noble metal catalysts. [ABSTRACT FROM AUTHOR]