Engineering Ag-O-Mn bridges with enhanced oxygen mobility over Ag substituted LaMnO3 perovskite catalyst for robustly boosting toluene combustion

Abstract

Perovskite oxide, as a promising candidate for volatile organic compounds combustion, is incapable in practical application at present due to its low intrinsic activity resulting from inadequate active oxygen species. However, balancing the concentration of active oxygen species and robust structure for perovskite oxide is still challenging. Herein, an efficient perovskite-based catalyst (denoted as TA-La0.9Ag0.1MnO3) was constructed through Ag substitution and subsequently tartaric acid etching of LaMnO3, which exhibits robustly boosted catalytic performance for toluene combustion compared with pristine LaMnO3, causing a ∼100 °C lower T90. In this study, Ag substitution could weaken the La-O hybridization, which effectively facilitates La cations removal by subsequent acid etching, thus sufficiently exposing active Ag and Mn species and generating more surface lattice oxygen, but also constructs Ag-Mn-O bridges within the matrix of Ag substituted LaMnO3. Acid etching enables the activation of Ag-O-Mn bridges with strong electron transfer ability from O to Ag atom, promoting the mobility of lattice oxygen, and consequently the low-temperature oxidation ability. Additionally, the exposed Ag and Mn as Lewis acid sites can effectively improve the adsorption capacity toward toluene molecules, which synergistically facilitates the toluene abatement. Notably, TA-La0.9Ag0.1MnO3 also exhibits superb long-term stability, water-resistance, and high thermal stability up to 650 °C.