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⁺−O_v−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⁺−O_v−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 (E_CeO2,SO2= –3.48 eV) than Mn₂O₃ core (E_Mn2O3,SO2= –0.87 eV), thus avoiding its toxic effects on the interior active sites and endowing Mn₂O₃ @CeO₂ a superior SO₂-resistance.