A selective catalytic reduction (SCR) catalyst includes a support layer. A copper-loaded chabazite (Cu/CHA) layer is supported on the support layer. A copper-loaded beta zeolite (Cu/beta) is supported on the Cu/CHA layer. The Cu/beta may be hydrothermally pre-aged prior to use of the SCR catalyst in a vehicle. The pre-aged Cu/beta is essentially free of phosphorous (P), calcium (Ca), zinc (Zn), sodium (Na), potassium (K), magnesium (Mg), iron (Fe), CaSO.sub.4, Ca.sub.19Zn.sub.2(PO.sub.4).sub.14, CaZn.sub.2(PO.sub.4).sub.2, ash, and/or soot.

Hydrocarbon (HC) traps are disclosed. The HC trap may include a first zeolite material having an average pore diameter of at least 5.0 angstroms and configured to trap hydrocarbons from an exhaust stream and to release at least a portion of the trapped hydrocarbons at a temperature of at least 225° C. The HC trap may also include a second zeolite material having an average pore diameter of less than 5.0 angstroms or larger than 7.0 angstroms. One or both of the zeolite materials may include metal ions, such as transition, Group 1A, or platinum group metals. The HC trap may include two or more discrete layers of zeolite materials or the two or more zeolite materials may be mixed. The multiple zeolite HC trap may form coke molecules having a relatively low combustion temperature, such as below 500° C.

An emissions treatment system for an exhaust stream of an internal combustion engine including hydrocarbons, carbon monoxide, and nitrogen oxides is provided. The disclosed system can include an exhaust conduit in fluid communication with the internal combustion engine via an exhaust manifold; a first three-way conversion catalyst (TWC-1) located downstream of the internal combustion engine in the exhaust conduit; an SCR-HCT catalyst comprising a selective catalytic reduction catalyst and a hydrocarbon trap downstream of the TWC-1 in the exhaust conduit; and a third catalyst downstream of the SCR-HCT combination in the exhaust conduit, the third catalyst comprising a platinum group metal (PGM) e.g., in an amount effective to oxidize hydrocarbons. Methods of making and using such systems and components thereof are also provided.

An after-treatment system includes, in series along an exhaust gas flow direction through the after-treatment system: a diesel oxidation catalyst (DOC), a diesel exhaust fluid (DEF) delivery device, a soot-reducing device and a selective catalytic reduction (SCR) catalyst.

A layered catalyst composite for the treatment of exhaust gas emissions, effective to provide lean NO.sub.x trap functionality and three-way conversion functionality is described. Layered catalyst composites can comprise catalytic material on a substrate, the catalytic material comprising at least two layers. The first layer comprising rare earth oxide-high surface area refractory metal oxide particles, an alkaline earth metal supported on the rare earth oxide-high surface area refractory metal oxide particles, and at least one first platinum group metal component supported on the rare earth oxide-high surface area refractory metal oxide particles. The second layer comprising a second platinum group metal component supported on a first oxygen storage component (OSC) and/or a first refractory metal oxide support and, optionally, a third platinum group metal supported on a second refractory metal oxide support or a second oxygen storage component.

To reduce an OSC material, while maintaining necessary OSC capacity; and to improve heat resistance and reactivity of a precious metal. Proposed is an exhaust gas purifying catalyst which comprises a first catalyst layer that is formed on the surface of a substrate that is formed of a ceramic or a metal, and a second catalyst layer that is formed on the upper side of the first catalyst layer. The first catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:7 to 1:3. The second catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:1 to 10:0.

Provided is a catalytic converter in which the entire catalyst constituting the catalytic converter can be efficiently utilized to purify exhaust gas, and the emission of hydrogen sulfide can be suppressed. A catalytic converter 10 includes catalyst layers 2A, 2B formed of a noble metal catalyst that are formed on cell wall surfaces of a substrate 1 having a cell structure in a longitudinal direction of the substrate 1 in which gas flows, in which the substrate 1 has a center region 1A having a relatively high cell density and a peripheral region 1B having a relatively low cell density, and lengths of the catalyst layers 2A, 2B of the center region 1A and the peripheral region 1B in the longitudinal direction are the same as each other, or the length of the catalyst layer 2B in the longitudinal direction is shorter than that of the catalyst layer 2A.

An exhaust gas purification catalytic device 1 contains Pt, Pd, and Rh as catalytic metals. The catalytic metal Pt is loaded on silica-alumina which serves as a support, and Pt-loaded silica-alumina obtained by loading the Pt on the silica-alumina is contained in a catalytic layer with which an exhaust gas contacts first.

The present application discloses a monolithic catalyst with the function of selective adsorption-catalytic oxidation of organic waste gas and a preparation method and application thereof. The present application adopts a double coating design. A first coating is a molecular sieve primer coating. A second coating is an active component coating, which uses a neutral silica sol, so as to protect the activity and effectiveness of a noble metal and a catalytic promoter on the molecular sieve.

The invention relates to a catalyst system for reducing nitrogen oxides, which comprises a nitrogen oxide storage catalyst and an SCR catalyst, wherein the nitrogen oxide storage catalyst consists of at least two catalytically active washcoat layers on a supporting body, wherein a lower washcoat layer A contains cerium oxide, an alkaline earth compound and/or alkali compound, as well as platinum and palladium, and an upper washcoat layer B, which is arranged over the washcoat layer A, contains cerium oxide, platinum and palladium, and no alkali compound and no alkaline earth compound. The invention also relates to a method for converting NOx in exhaust gases of motor vehicles that are operated by means of engines that are operated in a lean manner.