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.

Disclosed are zeolite catalysts having the CHA crystal structure with a low silica to alumina ratio, as well as articles and systems incorporating the catalysts and methods for their preparation and use. The catalysts can be used to reduce NOx from exhaust gas streams, particularly those emanating from gasoline or diesel engines.

A process for preparing a catalyst comprising a zeolitic material comprising copper, the process comprising (i) preparing an aqueous mixture comprising water, a zeolitic material comprising copper, a source of copper other than the zeolitic material comprising copper, and a non-zeolitic oxidic material selected from the group consisting of alumina, silica, titania, zirconia, ceria, a mixed oxide comprising one or more of Al, Si, Ti, Zr, and Ce and a mixture of two or more thereof; (ii) disposing the mixture obtained in (i) on the surface of the internal walls of a 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 substrate extending therethrough; and optionally drying the substrate comprising the mixture disposed thereon; (iii) calcining the substrate obtained in (ii).

A three-way catalyst article, and its use in an exhaust system for compressed natural gas engines, is disclosed. The catalyst article for treating exhaust gas from compressed natural gas (CNG) engine comprising: a substrate comprising an inlet end, an outlet end with an axial length L; a first catalytic region beginning at the outlet end and extending for less than the axial length L, wherein the first catalytic region comprises a first zeolite; and a second catalytic region beginning at the inlet end, wherein the second catalytic region comprises a second platinum group metal (PGM) component, a second oxygen storage capacity (OSC) material, and a second inorganic oxide; wherein the second PGM component is selected from the group consisting of palladium, platinum, rhodium or a combination thereof.

Disclosed herein is a continuous process for preparing zeolitic material with a CHA-type framework structure comprising SiO.sub.2 and X.sub.2O.sub.3 and the zeolitic material so-obtained. The processes comprises (i) preparing a mixture comprising one or more sources of SiO.sub.2, one or more sources of X.sub.2O.sub.3, seed crystals, one or more tetraalkylammonium cation R.sup.5R.sup.6R.sup.7R.sup.8N.sub.+-containing compounds as structure directing agent, and a liquid solvent system; (ii) continuously feeding the mixture prepared in (i) into a continuous flow reactor at a liquid hourly space velocity; and (iii) crystallizing the zeolitic material with a CHA-type framework structure from the mixture in the continuous flow reactor.

The present disclosure provides catalyst compositions capable of reducing nitrogen oxide (NO.sub.x) emissions in engine exhaust. The catalyst compositions include metal ion-exchanged zeolites having a domain size of less than about 1500 Ångstroms (Å), a crystallographic strain of less than about 0.7%, or both. Further provided are catalyst articles coated with such compositions, processes for preparing such catalyst compositions and articles, an exhaust gas treatment system including such catalytic articles, and methods for reducing NO.sub.x in an exhaust gas stream using such catalytic articles and systems.

A method of coating a substrate with a foam is described. The method comprises: (a) introducing a foam into a substrate comprising a plurality of channels through open ends of the channels at a first end of the substrate; and (b) applying at least one of (i) a vacuum to open ends of the channels at a second end of the substrate and (ii) a pressure to the open ends of the channels at the first end of the substrate; wherein the foam comprises a particulate material, and wherein the foam is particle stabilized.

Catalytic compositions and sequential catalytic methods are generally described. in some embodiments, a composition comprises a first catalyst comprising a Cu-modified zeolite, and a second catalyst capable of a coupling reaction between (a) an intermediate resulting from a reaction of a reactant at the first catalyst, and (b) a co-reagent, wherein a rate of diffusion of the co-reagent within one or more cages and/or pores of the first catalyst is lower than a rate of diffusion of the intermediate within the one or more cages and/or pores of the first catalyst.

A gas purification catalyst device comprises: a substrate; and one or more catalyst layers on the substrate. Among the one or more catalyst layers, at least one catalyst layer contains both Cu-CHA-type zeolite particles and iron-supporting metal oxide particles in which iron is supported on metal oxide particles.

The present invention relates to a catalyst for the oxidation of NO, for the oxidation of ammonia and for the selective catalytic reduction of NOx, comprising a substrate, a first coating comprising one or more of a vanadium oxide and a zeolitic material comprising one or more of copper and iron; and a second coating comprising a platinum group metal component supported on a non-zeolitic oxidic material, wherein the second coating further comprises a zeolitic material comprising one or more of copper and iron.