Precise fabrication of surface-reconstructed LaMnO3 perovskite with enhanced catalytic performance in CH4 oxidation

In this study, MnOx/LaMnO3 catalyst (LMO) was successfully synthesized through a selectively etched method, wherein MnOx was in-situ formed on the surface of LaMnO3. The modified LMO catalysts possessed the large specific surface area, high molar ratios of Mn4+ /(Mn-4 + Mn3+), and outstanding low-temperature reducibility. Moreover, the more efficient electron transfer from Mn3+/Mn4+ redox cycles and O-2 double left right arrow O-L due to the generation of oxygen defects contributed to the strong interaction between MnOx and LaMnO3. Among all LMO catalysts, the LMO-4 (etched 40 min) catalyst exhibited the excellent activity (T-90 at 448 degrees C), stability and optimum endurability in methane catalytic combustion (5 vol% water) during the steady state of 100 h, which could be greatly assigned to its larger specific surface area, superior low temperature reducibility, the highest molar ratio Mn4+ and better oxygen mobility. The lowest apparent activation energy (E-a) of LMO-4 catalyst (61.8 kJ/mol) was in good accordance with its optimum catalytic activity for methane combustion.