Asymmetric oxygen vacancy-enriched Mn2O3@CeO2 for NO oxidation with excellent low-temperature activity and boosted SO2-resistance

The development of highly active and SO2-resistant catalysts is a major hurdle in the catalytic oxidation of NO to NO2. Herein, we fabricate a core–shell Mn2O3 @CeO2 catalyst using a two-step method for NO oxidation. Benefiting from the generation of abundant Mn4+−Ov−Ce3+ interfacial sites and plentiful oxygen vacancies, the resulting Mn2O3 @CeO2 exhibits a superior low-temperature NO-to-NO2 capacity (T50 at 183 °C and T86 at 275 °C), obtaining a remarkable temperature reduction compared to commercial Pt/γ-Al2O3 catalyst (T50 at 262 °C). Meanwhile, In-situ Raman and In-situ Drifts reveal that Mn4+−Ov−Ce3+ interfacial site is the main adsorption site for the formation of N-containing intermediates, which plays a decisive role in the NO oxidation reaction. More encouragingly, SO2 shows a much higher affinity for CeO2 sheath (ECeO2,SO2= –3.48 eV) than Mn2O3 core (EMn2O3,SO2= –0.87 eV), thus avoiding its toxic effects on the interior active sites and endowing Mn2O3 @CeO2 a superior SO2-resistance.