Patent ID: 8765092

Claim:
A method of oxidizing NO to NO 2 in an exhaust aftertreatment system for a hydrocarbon-fueled engine, the method comprising: (a) supplying a mixture of air and fuel to a hydrocarbon-fueled engine, the mixture of air and fuel being defined by an air to fuel mass ratio that is lean of stoichiometry; (b) combusting the mixture of air and fuel in the hydrocarbon-fueled engine to produce an exhaust flow that contains a NO X content, the NO X content including NO and NO 2 at a NO:NO 2 molar ratio; and (c) exposing the exhaust flow to an oxidation catalyst with a NO to NO 2 oxidative activity sufficient to reduce the NO:NO 2 molar ratio of the NO X content of the exhaust flow, the oxidation catalyst being particles of a non-stoichiometric perovskite oxide having the formula La X MnO Y in which X ranges from 0.85 to 0.95 and Y ranges from 3.0 to 3.30, the non-stoichiometric La X MnO Y perovskite oxide particles having a diameter that ranges from 10 nm to 100 μm and being present at a loading of 5 grams to 200 grams per liter of flow volume over to the non-stiochiometric perovskite oxide particles.