Fig. 2: Oxidation activity of diesel exhaust gas.

a NO oxidation activity of Pt/Al2O3, SmMn2O5 (SMO), Mn2O3, Mn2O3/SmMn2O5 (Mn2O3/SMO), and Mn2O3-SmMn2O5 (Mn2O3-SMO). b Plot of maximum conversion for NO oxidation vs. temperature for Mn2O3/SMO, mullite-based catalysts, perovskite-based catalysts, and noble metal catalysts. c Diesel oxidation catalyst (DOC) performance of SMO, Mn2O3/SMO, and Pt/Al2O3. d DOC stability of Mn2O3/SMO for long-term oxidation reaction at 300 °C. Reaction conditions: 500 ppm NO, 1% CO, 2000 ppm C3H6, 10% O2, 5 ± 1% H2O, and balance N2.