A passive NO.sub.x adsorber is disclosed. The passive NO.sub.x adsorber is effective to adsorb NO.sub.x at or below a low temperature and release the adsorbed NO.sub.x at temperatures above the low temperature. The passive NO.sub.x adsorber comprises a noble metal and a molecular sieve having an LTL Framework Type. The invention also includes an exhaust system comprising the passive NO.sub.x adsorber, and a method for treating exhaust gas from an internal combustion engine utilizing the passive NO.sub.x adsorber.

A passive NOx absorber for treating an exhaust gas from a diesel engine is described. The passive NOx absorber comprises a first washcoat region comprising a zeolite catalyst, the zeolite catalyst comprising a noble metal and a zeolite having a SAR of 2-15.

The present disclosure is directed to an emission treatment system for NO.sub.x abatement in an exhaust stream of an ammonia-fueled engine, the emission treatment system including a selective catalytic reduction (SCR) catalyst disposed on a substrate in fluid communication with the exhaust stream, an oxidation catalyst disposed on a substrate positioned either upstream or downstream of the SCR catalyst and in fluid communication with the exhaust stream and the SCR catalyst, and optionally, one or more adsorption components disposed on a substrate positioned upstream and/or downstream of the SCR catalyst and in fluid communication with the exhaust stream and the SCR catalyst, the adsorption component chosen from low temperature NO.sub.x adsorbers (LT-NA), low temperature ammonia adsorbers (LT-AA), low temperature water vapor adsorbers (LT-WA), and combinations thereof. The disclosure further provides a related method of treatment of an exhaust gas.

An exhaust gas purifying system for an engine includes a three-way catalyst, a particulate filter, an ammonia sorbent unit, an exhaust gas purifying catalyst unit, and a gas injection component including an oxygen-containing gas, all coupled to an exhaust line. Methods for purifying exhaust gas from an engine include exposing the exhaust gas to a three-way catalyst and a particulate filter, thus generating ammonia. The ammonia may be stored in an ammonia sorbent unit during a cold start condition. An oxygen-containing gas may be injected into the exhaust line. Once the ammonia sorbent has reached a desorption temperature, the ammonia may be released into the exhaust line and exposed to an exhaust gas purifying catalyst unit. The exhaust gas purifying catalyst partially oxidizes the ammonia to nitrous oxides (NOx) and subsequently catalyzes a reaction between the remaining ammonia and the nitrous oxides to give nitrogen gas and water.

A Nitrogen Oxide (NOx) sorbent material of the present invention includes a multi-metallic oxide that includes one or more alkali or alkaline earth metal, one or more 3d transition metal, and one or more rare earth element. The NOx sorbent material is configured to adsorb and absorb NOx below a low temperature and to release the adsorbed or absorbed NOx at temperature at or above the low temperature. In some embodiments, a manganese catalyst is deposited on a high surface area carrier. The manganese catalyst takes the form of an alkali/metal promotor and an Mn-based compound. In general, the NOx sorbent material contains about one percent to about fifty percent by weight of alkali/alkaline earth metal manganese catalyst based on the total weight of the catalyst.

An exhaust system for an internal combustion engine, the exhaust system comprising, a lean NO.sub.x trap (LNT), a wall flow monolithic substrate having a NO.sub.x storage and reduction zone thereon, the wall flow monolithic substrate having a pre-coated porosity of 40% or greater, the NO.sub.x storage and reduction zone comprising a platinum group metal loaded on a first support, the first support comprising one or more alkaline earth metal compounds, a mixed magnesium/aluminium oxide, cerium oxide, and at least one base metal oxide selected the group consisting of copper oxide, manganese oxide, iron oxide and zinc oxide.

Provided is a system for treating a flowing exhaust gas comprising a lean NOx trap, a catalyzed soot filter, an ammonia or an ammonia precursor metering system for metering ammonia or an ammonia precursor into the flowing exhaust gas; and an SCR catalyst, wherein the SCR catalyst is disposed downstream of the lean NOx trap and comprises copper and/or iron supported on a small pore molecular sieve.

An exhaust-gas aftertreatment device for an internal combustion engine, for use in a motor vehicle, includes an exhaust tract with at least one exhaust pipe and at least one exhaust-gas aftertreatment element. The exhaust-pipe internal wall and/or the at least one exhaust-gas aftertreatment element have/has a vapor-sorbing material forming at least one exhaust-tract-side sorption element.

An after-treatment system includes, in series along an exhaust gas flow direction through the after-treatment system: a diesel oxidation catalyst (DOC) or a passive NOx adsorber (PNA), a diesel exhaust fluid (DEF) delivery device, a soot-reducing device and a selective catalytic reduction (SCR) catalyst, which may also include an additional PNA.

The present invention relates to a VOC reduction system and a VOC reduction method that applies pulse type thermal energy to a catalyst to activate the catalyst and oxidizes and removes the VOC.