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.

A catalyst includes a zeolite, wherein the zeolite has: a CHA framework; a particle size less than or equal to 100 nanometers; and a silica to alumina mole ratio in the range of about 50:1 to about 150:1. The catalyst can include a metal dopant. The catalyst can be used for purifying a product by flowing a reactant across the catalyst to form the product; and condensing or separating the product. The product can be an olefin or alkenes with an increased carbon chain. The catalyst can be used for selective catalytic reduction of nitrogen oxide or a gas to liquid reaction. A method of producing the catalyst can include selecting the concentration of a crystal growth inhibitor based on the ratio of the silica precursor and an alumina precursor such that the zeolite crystals have a mean particle size less than or equal to 100 nanometers.

Described are a catalyst capable of effectively oxidizing an exhaust gas, a method for preparing the catalyst, and a method for oxidizing an exhaust gas using the catalyst. The exhaust gas oxidation catalyst includes at least two layers, a lower catalyst layer and an upper catalyst layer, laminated on a three-dimensional structure, wherein the lower catalyst layer and the upper catalyst layer independently contain precious metal and alumina and/or zeolite, and at least a part of the upper catalyst layer contains pores derived from a pore connecting agent with a combustion decomposition temperature of 300° C. or more to less than 450° C.

An aftertreatment system (100) includes a decomposition chamber (108), a reductant pump (120), a first dosing module (110), a second dosing module (112), and a controller (133). The first dosing module (110) is coupled to the decomposition chamber (108) and configured to receive reductant from the reductant pump (120). The second dosing module (112) is coupled to the decomposition chamber (108) and configured to receive reductant from the reductant pump (120) independent of the first dosing module (110). The controller (133) is communicatively coupled to the first dosing module (110) and the second dosing module (112). The controller (133) is configured to independently control a first volumetric flow rate of reductant provided from the first dosing module (110) into the decomposition chamber (108) and a second volumetric flow rate of reductant provided from the second dosing module (112) into the decomposition chamber (108).

The present invention relates to a selective catalytic reduction catalyst for the treatment of an exhaust gas of a diesel engine comprising (i) a flow-through substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the flow-through substrate extending therethrough; (II) a coating disposed on the surface of the internal walls of the substrate, where-in the surface defines the interface between the passages and the internal walls, wherein the coating comprises a vanadium oxide supported on an oxidic material comprising titania, and further comprises a mixed oxide of vanadium and one or more of iron, erbium, bismuth, cerium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium, yttrium, molybdenum, tungsten, manganese, cobalt, nickel, copper, aluminum and antimony.

An exhaust gas purification catalyst (C), including a three-dimensional structure (10) and a catalyst component layer (20) supported on the three-dimensional structure (10), where the average thickness of the catalyst component layer (20) is 15 μm or more to 200 μm or less, the average particle size of the catalyst component is 2 μm or more to 10 μm or less, and the catalyst component particle size variation coefficient is 10 or more and less than 50. The particle distribution of the catalyst component can be 90% or more to 99.9% or less.

The present disclosure provides perovskite catalytic materials and catalysts comprising platinum-group metals and perovskites. These catalysts may be used as oxygen storage materials with automotive applications, such as three-way catalysts. They are also useful for water or CO.sub.2 reduction, or thermochemical energy storage.

A lean NO.sub.x trap catalyst and its use in an emission treatment system for internal combustion engines is disclosed. The lean NO.sub.x trap catalyst comprises a first layer for storing nitrogen oxides (NOx) under lean exhaust gas conditions and releasing and/or reducing stored NOx during rich exhaust gas conditions, and a second layer, said second layer comprising a first zone for oxidizing carbon monoxide (CO) and/or hydrocarbons (HC), and a second zone for oxidizing nitric oxide (NO), and a substrate having an inlet end and an outlet end.

One object is to provide a useful aldehyde decomposition catalyst, and an exhaust gas treatment apparatus and an exhaust gas treatment method using the aldehyde decomposition catalyst that achieve low cost and sufficient aldehyde decomposition performance with a small amount of the catalyst. An aldehyde decomposition catalyst of the present invention is made of a zeolite in a cation form NH.sub.4 having a structure of CHA or MOR and carrying Cu.

A process for preparing a zeolitic material having framework type AEI and having a framework structure which comprises a tetravalent element Y, a trivalent element X, and oxygen, said process comprising (i) providing a zeolitic material having framework type CHA and having a framework structure comprising the tetravalent element Y, the trivalent element X, and oxygen; (ii) preparing a synthesis mixture comprising the zeolitic material provided in (i), water, a source of the tetravalent element Y other than the zeolitic material provided in (i), and an AEI framework structure directing agent; (ili) subjecting the synthesis mixture prepared in (ii) to hydrothermal synthesis conditions comprising heating the synthesis mixture to a temperature in the range of from 100 to 200° C. and keeping the synthesis mixture at a temperature in this range under autogenous pressure, obtaining the zeolitic material having framework type AEI; wherein Y is one or more of Si, Ge, Sn, Ti, Zr; wherein X is one or more of Al, B, Ga, In; wherein in the framework structure of the zeolitic material provided in (i), the molar ratio Y:X, calculated as YO2: X2O3, is at most 20:1 and, wherein; the process further comprises supporting a metal M selected from the transition metals of groups 7 to 12 of the periodic system of elements.