A citric acid-assisted deposition strategy to synthesize mesoporous SiO2-confined highly dispersed LaMnO3 perovskite nanoparticles for n-butylamine catalytic oxidation

Catalytic oxidation can efficiently eliminate nitrogen-containing volatile organic compounds (NVOCs) and suppress the generation of toxic NOx in order to avoid secondary pollution. In this study, mesoporous SiO2-confined LaMnO3 perovskite nanoparticles with high dispersion were successfully prepared by a citric acid-assisted deposition method (LMO/SiO2-SD) and tested for the oxidation of n-butylamine. The method utilized the synergistic effect of abundant active hydroxyl groups existing on the SiO2 gel surface and citric acid, rendering the metal ions more uniformly scattered on the SiO2 surface. Strikingly, the LMO/SiO2-SD sample exhibited the optimum catalytic performance (T90 at 246 °C) and the highest N2 selectivity, which was mainly ascribed to its abundant surface acid sites, superior low-temperature reducibility and higher ratio of surface Mn4+ species. The apparent activation energy (Ea) for n-butylamine oxidation over LMO/SiO2-SD sample was 29.0 kJ mol−1. Furthermore, the reaction mechanism of n-butylamine oxidation was investigated by in situ FITR and a reasonable reaction route for n-butylamine oxidation over the LMO/SiO2-SD sample was proposed.