This honeycomb catalyst is provided with a honeycomb unit in which a plurality of through holes are arranged in parallel in a longitudinal direction with being separated by partition walls, wherein the honeycomb unit contains a zeolite and an inorganic binder, the zeolite satisfies all of conditions (A) to (D): (A) having a CHA structure in which the composition ratio of SIO.sub.2/Al.sub.2O.sub.3 is less than 15; (B) having Cu being carried by 3.5 to 6.0 wt % with respect to zeolite; (C) having an average particle diameter of 0.05 to 1 μm; and (D) being contained by 150 to 350 g/L with respect to the whole of the honeycomb unit, and excellent NOx purifying performance, reduction of water absorption and displacement, and inhibition of crack occurrence can be exerted.

The honeycomb structure includes a honeycomb structure body made of a zeolite material containing at least a coarse particle zeolite having a large average particle diameter (coarse zeolite particles). A fine particle zeolite having an average particle diameter smaller than that of the coarse particle zeolite (fine zeolite particles), and an inorganic bonding material, the coarse particle zeolite (the coarse zeolite particles) is a chabazite type zeolite in which an average particle diameter of primary particles is 2 μm or more and 6 μm or less, and in the fine particle zeolite (the fine zeolite particles), an average particle diameter of primary particles is 0.02 μm or more and smaller than 2 μm, and in the zeolite material which is comprised the honeycomb structure body, a ratio of a volume of pores having pore diameters of 0.02 to 0.15 μm to a volume of all pores is 42% or less.

The manufacturing method includes a step of mixing a coarse particle zeolite, a fine particle zeolite, and a raw material of an inorganic bonding material to prepare a zeolite raw material; a step of forming the prepared zeolite raw material into a honeycomb shape to prepare a honeycomb formed body; and a step of firing the prepared honeycomb formed body to prepare the honeycomb structure. In the step of preparing the zeolite raw material, as the coarse particle zeolite, a chabazite type zeolite having a specific average particle diameter, the fine particle zeolite having a specific average particle diameter, the raw material of the inorganic bonding material which includes at least basic aluminum lactate is used.

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.

A method is disclosed for the preparation of a metal exchanged microporous materials, e.g. metal exchanged silicoaluminophosphates or metal exchanged zeolites, or mixtures of metal exchanged microporous materials, comprising the steps of providing a dry mixture of a) one or more microporous materials that exhibit ion exchange capacity and b) one or more metal compounds; heating the mixture in a gaseous atmosphere containing ammonia and one or more oxides of nitrogen to a temperature and for a time sufficient to initiate and perform a solid state ion exchange of ions of the metal compound and ions of the microporous material; and obtaining the metal-exchanged microporous material.

A process for producing a ceramic catalyst involves the steps of: a) providing functional particles having a catalytically inactive pore former as a support surrounded by a layer of a catalytically active material, b) processing the functional particles with inorganic particles to form a catalytic composition, c) treating the catalytic composition thermally to form a ceramic catalyst, wherein the ceramic catalyst comprises at least porous catalytically inactive cells which are formed by the pore formers in the functional particles, which are embedded in a matrix comprising the inorganic particles, which form a porous structure and which are at least partly surrounded by an active interface layer comprising the catalytically active material of the layer of the functional particles.

An SCR catalyst produced in by this method has an improved NO.sub.x conversion rate compared to a conventionally produced SCR catalyst.

An AFI-CHA hybrid crystal molecular sieve and an NH.sub.3-SCR catalyst using the AFI-CHA hybrid crystal molecular sieve as a carrier, and preparation methods thereof are disclosed. The AFI-CHA hybrid crystal molecular sieve includes an AFI-type SAPO-5 molecular sieve and a CHA-type SAPO-34 molecular sieve, with hybrid crystal grains of AFI and CHA. The hybrid crystal molecular sieve is synthesized by a hydrothermal synthesis method and can be obtained by changing the structure directing agent, the heating rate and the calcinating temperature in the preparation process. Further, copper is loaded on the basis of the hybrid crystal molecular sieve to prepare copper-based NH.sub.3-SCR catalyst and corresponding monolithic catalyst. The catalytic activity and hydrothermal stability of the catalyst are significantly improved by the hybrid crystal molecular sieve.

A catalyst includes LTA zeolite including copper ions, wherein a Si/Al ratio of the LTA zeolite is 2 to 50. The catalyst is coated on a honeycomb carrier or a filter. The catalyst removes NOx from a reaction gas at 100° C. or above. The catalyst has an NOx conversion rate of 80% at 450° C. or above.

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 synthetic aluminosilicate zeolite catalyst containing at least one catalytically active transition metal selected from the group consisting of Cu, Fe, Hf, La, Au, In, V, lanthanides and Group VIII transition metals, which aluminosilicate zeolite is a small pore aluminosilicate zeolite having a maximum ring size of eight tetrahedral atoms, wherein the mean crystallite size of the aluminosilicate zeolite determined by scanning electron microscope is >0.50 micrometer.