Pseudo core-shell LaCoO3@MgO perovskite oxides for high performance methane catalytic oxidation

Abstract

Magnesia modified LaCoO3 was prepared by a facile one-step sol-gel method and used for removal of dilute methane. Compared with the conventional doping technique, the obtained LaCoO3@MgO-x exhibits pseudo core-shell structure and shows superior catalytic activity. The methane conversion exceeds 90% at 532 °C on LaCoO3@MgO-0.1, while only 60% of methane is conversed using the doped perovskite LaCo0.9Mg0.1O3. The high catalytic performance of LaCoO3@MgO-0.1 is mainly attributed to the adjustment of surface acid-base properties by the MgO shell structure. According to density functional theory (DFT) calculation, the methane is more likely to be adsorbed and cracked on LaCoO3@MgO-0.1. The in situ DRIFTS shows that CH3–O–CH3 intermediate specie is formed. The pseudo core-shell structure also enhances the stability and the LaCoO3@MgO-0.1 maintains high activity after working for 100 h. The above results demonstrate that surface modification by magnesia is an effective strategy for improving LaCoO3 catalytic performance.