Catalytic Degradation of Toluene over MnO2/LaMnO3: Effect of Phase Type of MnO2 on Activity

Series of alpha, beta, gamma, delta type MnO2 supported on LaMnO3 perovskite was developed by a one-pot synthesis route. Compared with alpha-MnO2, beta-MnO2, gamma-MnO2, delta-MnO2 and LaMnO3 oxides, all MnO2/LaMnO3 showed promotional catalytic performance for toluene degradation. Among them, alpha-MnO2/LaMnO3 holds the best active and mineralization efficiency. By the analysis of N-2 adsorption-desorption, XPS and H-2-TPR, it can be inferred that the improved activity should be ascribed to the higher proportion of lattice oxygen, better low-temperature reducibility and larger specific surface area. Besides, the byproducts from the low-temperature reaction of toluene oxidation were detected by a TD/GC-MS, confirming the presence of the intermediates. Combined with the in-situ DRIFTS, the catalytic degradation path of toluene oxidation has also been discussed in depth.