A nitrous oxide (N.sub.2O) removal catalyst composition for treating an exhaust stream of an internal combustion engine is provided, containing a platinum group metal (PGM) component on a metal oxide-based support, wherein the N.sub.2O removal catalyst composition is in a substantially reduced form, such that it has an oxygen deficiency of about 0.05 mmol oxygen atoms/g or greater, and wherein the N.sub.2O removal catalyst composition provides effective removal of at least a portion of N.sub.2O from the exhaust stream under lean conditions at a temperature of about 350 C. or lower. N.sub.2O removal catalytic articles, systems, and methods are also provided for removing at least a portion of N.sub.2O from an exhaust stream under lean, low temperature conditions.

A catalyst article and its use in an exhaust system for internal combustion engines is disclosed. The catalyst article comprises a substrate which is a wall-flow filter, a first catalyst composition, and a second catalyst composition. The first and second catalyst compositions each independently comprise an oxygen storage component (OSC) derived from a CeZr mixed oxide sol having a D90 of less than 1.3 micron and a particulate inorganic oxide having a D90 of from 1 to 20 microns.

A cerium manganese catalyst for ozone decomposition, which is mainly a composite oxide of Mn.sub.2O.sub.3 and CeO.sub.2 with the chemical constitution of CeMn.sub.aO.sub.x, a being a natural number selected from 6 to 15. A method for preparing a catalyst comprises: mixing a solution containing a cerium source and a manganese source with excessive urea, reacting to obtain a precipitate, washing the precipitate to neutral, drying, and roasting to obtain the cerium manganese catalyst.

The present disclosure generally provides low-temperature nitrogen oxides (NO.sub.x) adsorbers used in the treatment of a NO.sub.x-containing exhaust gas stream and to methods of preparing and using the same. In particular, the NO.sub.x adsorber composition includes an active metal and a metal oxide support, wherein the metal oxide support includes greater than 50% by weight ceria based on the total weight of the NO.sub.x adsorber composition, and wherein the active metal includes about 0.01% to about 5% by weight ruthenium based on the total weight of the NO.sub.x adsorber composition.

A gas purification device includes: a converter packed with a catalyst for hydrolyzing both carbonyl sulfide and hydrogen cyanide; an upstream heat exchanger for heat exchange between a gas to be introduced into the converter and a cooling fluid for cooling the gas; a reaction-temperature estimation member for estimating a reaction temperature inside the converter; and a flow-rate adjustment member for adjusting a flow rate of the cooling fluid flowing into the upstream heat exchanger based on an estimated value of the reaction-temperature estimation member to control the reaction temperature.

An after treatment method for a lean-burn engine is disclosed. The after treatment method is configured to control an after treatment system sequentially equipped with an ammonia production catalyst module, a selective catalytic reduction (SCR) catalyst, and a CO clean-up catalyst (CUC) on an exhaust pipe through which an exhaust gas flows and which is connected to a lean-burn engine. In the after treatment method, a rich air/fuel ratio (AFR) is controlled in multiple phases in response to detecting that conversion to the rich AFR is desired.

An apparatus for purifying exhaust gas includes: an engine; an exhaust gas air-fuel ratio adjustor for adjusting an air-fuel ratio of the exhaust gas; a lean NO.sub.x trap (LNT) mounted on the exhaust pipe and generating ammonia or reducing nitrogen oxides or desorbed nitrogen oxides contained in the exhaust gas using a reducing agent including carbon monoxide, hydrocarbon, or hydrogen contained in the exhaust gas; a three way catalyst (TWC) mounted on the exhaust pipe at a rear end of the LNT, and converting noxious gas in the exhaust gas into harmless components through a redox reaction; and a controller controlling the air-fuel ratio of the exhaust gas to a stoichiometric air-fuel ratio when the nitrogen oxide storage or purification performance of the LNT is in the operating period of the engine less than a predetermined level.

The invention discloses a method for simultaneously removing SO.sub.2 and NO.sub.x in flue gas: uniformly mixing a water-soluble ruthenium salt with ammonia water to obtain an aqueous solution of a ruthenium-amine complex; subjecting the flue gas and the aqueous solution of the ruthenium-amine complex to a countercurrent contact reaction under the temperature of 5-60 C., pH of 7.5-12 to obtain a solution A and purified gas; discharging the solution A of the step (2) into a crystallization tank to crystallize and separate an ammonium salt to obtain a solution B, returning the solution B to replace the aqueous solution of the ruthenium-amine complex. The invention utilizes the ruthenium-amine complex having a strong capability of complexing with NO as well as residual oxygen in the flue gas to carry out liquid phase catalytic oxidation to convert the NO.sub.x into ammonium nitrate, and the removal efficiency of the NO.sub.x and the SO.sub.2 is high.

A catalyst article including a substrate with an inlet side and an outlet side, a first zone and a second zone, where the first zone includes an ammonia slip catalyst (ASC) comprising a platinum group metal on a support and a first SCR catalyst; where the second zone includes a catalyst selected from the group consisting of a diesel oxidation catalyst (DOC) and a diesel exotherm catalyst (DEC); and where the first zone is located upstream of the second zone. The first zone may include a bottom layer with a blend of: (1) the platinum group metal on a support and (2) the first SCR catalyst; and a top layer comprising a second SCR catalyst, the top layer located over the bottom layer.

A hydrocarbon burner for an enclosed environment includes a heat exchanger having a first heat exchanger inlet connected to an inlet of the hydrocarbon burner and a first heat exchanger outlet connected to a heater, and a second heat exchanger inlet connected to a reactor outlet and a second heat exchanger outlet connected to an outlet of the hydrocarbon burner. A reactor includes a reactor inlet, the reactor outlet, and a catalyst mixture disposed in a reactor bed between the reactor inlet and the reactor outlet. The heater connects the first heat exchanger outlet to the reactor inlet. The reactor is a low temperature reactor configured to convert at least one hydrocarbon to at least one of H2O and CO2.