Improved durability of Co3O4 particles supported on SmMn2O5 for methane combustion†
To eliminate the aggregation of Co3O4 in the methane combustion process at high temperature, a thermally stable mullite structure, SmMn2O5 (SMO), was utilized as a support to improve the catalytic durability of Co3O4 particles. In detail, Co/SMO composite catalysts were prepared using the deposition–precipitation method with distinct Co/SMO nominal weight ratios of 5%, 30% and 50%. Later, their methane combustion performances under an oxygen-rich atmosphere were evaluated and compared. Meanwhile, their physical and chemical properties were characterized by XRD, Raman spectroscopy, the BET method, SEM, HRTEM, XPS, H2-TPR and O2-TPD. H2-TPR and O2-TPD results illustrated that the Co/SMO-50% catalyst showed the highest reducibility and it enhanced the mobility of oxygen species. As a result, the Co/SMO-50% sample exhibited the highest CH4 combustion catalytic activity among all the composite catalysts. Specifically, the T10, T50, and T90 for methane combustion were measured to be 334 °C, 390 °C, and 437 °C, very similar to those of Co3O4 catalyst. At the same time, the Co/SMO-50% catalyst showed improved durability, better performance after recycling, thermal aging and long-term experiments when compared to the Co3O4 catalyst.