摘要:
One embodiment of the invention may include a method comprising providing a product comprising a substrate comprising a perovskite catalyst, NOx stored in or on the substrate and particulate matter in or on the substrate; releasing at least some of the stored NOx and oxidizing the released NOx to form NO2, and reacting the NO2 with carbon in the particulate matter to form at least one of CO or CO2.
摘要:
A non-stoichiometric perovskite oxide having the general chemical formula LaXMnOY, in which the molar ratio of lanthanum to manganese (“X”) ranges from 0.85 to 0.95, can be used in particle form as an oxidation catalyst to oxidize NO to NO2 in an exhaust aftertreatment system for a hydrocarbon-fueled engine. The oxygen content (“Y”) fluctuates with variations in the molar ratio of lanthanum to manganese but generally falls somewhere in the range of 3.0 to 3.30. The crystal lattice adjustments spurred by the non-stoichiometric molar ratio of lanthanum to manganese are believed responsible for an enhanced NO oxidative activity relative to similar perovskite oxides with a higher molar ratio of lanthanum and manganese.
摘要:
A bi-functional catalyst material, a SCR converter that includes the bi-functional catalyst material, an exhaust aftertreatment system that includes the SCR converter, and a method for removing NOX contained in an exhaust flow produced by a lean-burn engine are disclosed. The bi-functional catalyst material can (1) oxidize NO to NO2 and (2) selectively reduce NOX to N2 when exposed to an exhaust mixture that comprises the exhaust flow from the lean-burn engine and a suitable reductant. The bi-functional catalyst material comprises metal oxide particles selected from the group consisting of perovskite oxide particles and manganese-based mixed metal oxide particles dispersed on a selective catalytic reduction (SCR) catalyst.
摘要:
One embodiment of the invention may include a product comprising a catalyst combination comprising a perovskite catalyst and a second catalyst that is not a perovskite catalyst.
摘要:
Ammonia in a gas stream comprising oxygen and nitrogen may be effectively completely oxidized to a mixture of NO and NO2 for further processing to nitric acid. The gas stream is flowed over fine particles of La1-xSrxCoO3 and/or La1-xSrxMnO3, and/or La1-xSrxFeO3 where x=about 0.1, 0.2, or 0.3. The particles are supported as catalyst layers on gas stream-contacting surfaces of a flow-through catalyzed oxidation reactor. These relatively inexpensive perovskite-type materials may be used to promote oxidation of ammonia at temperatures below about 450° C. to about 500° C. to selectively produce a mixture of NO and NO2. This mixture is suitable for further oxidation to NO2 for adsorption into water to make nitric acid.
摘要:
A method for removing NOX from an oxygen-rich exhaust flow produced by a combustion source that is combusting a lean mixture of air and fuel may include passing the oxygen-rich exhaust flow through an exhaust aftertreatment system that includes a NOX oxidation catalyst that includes perovskite oxide particles, a NOX storage catalyst, and a NOX reduction catalyst.
摘要:
A method of replacing or exchanging non-metal charge balancing cations located at ion-exchanges sites within SAPO frameworks with cations of a transition metal using a solid state ion-exchange process. Transition metal-containing particles are formed on surfaces of SAPO particles, and thereafter the particles are heated in air to initiate the solid-state ion-exchange process. The transition metal-containing particles and the SAPO particles are heated to a temperature and for an amount of time to produce transition metal cations, and for the transition metal cations to replace at least a portion of the non-metal cations located within the SAPO frameworks.
摘要:
An exhaust aftertreatment system for a lean-burn engine may include a lean NOX trap that comprises a catalyst material. The catalyst material may remove NOX gases from the engine-out exhaust emitted from the lean-burn engine. The catalyst material may include a NOX oxidation catalyst that comprises a perovskite compound.
摘要:
An exhaust aftertreatment system that includes a suitable combination of particulate catalyst materials is used to effectively reduce an amount of NOX to N2 and water in a high-oxygen content exhaust flow from an engine that is controlled to operate by cyclically burning lean and rich mixtures of air and fuel. The catalyst materials of the exhaust aftertreatment system comprise (1) lanthanum-based perovskite oxide particles to oxidize NO to NO2, (2) barium oxide particles to temporarily store NO2, (3) copper oxide nanoparticles chemically deposited onto particles of cerium oxides to reduce NOX to N2 and to generate NH3, and (4) particles of a selective reduction catalyst to temporarily store NH3 and to reduce any residual NOX to N2 and water before the exhaust flow from the engine is discharged to the atmosphere.
摘要:
One embodiment of the invention may include a product comprising a catalyst combination comprising a perovskite catalyst and a second catalyst that is not a perovskite catalyst.