Described is a catalyst composition suitable for use as a selective catalytic reduction catalyst, including small-pore molecular sieve particles having a pore structure and a maximum ring size of eight tetrahedral atoms and impregnated with a promoter metal, and metal oxide particles dispersed within the small-pore molecular sieve particles and external to the pore structure of the small-pore molecular sieve particles, wherein the metal oxide particles include one or more oxides of a transition metal or lanthanide of Group 3 or Group 4 of the Periodic Table. A method for preparing the catalyst, a method for selectively reducing nitrogen oxides, and an exhaust gas treatment system are also described.

An extruded honeycomb catalyst for nitrogen oxide reduction according to the selective catalytic reduction (SCR) method in exhaust gases from motor vehicles includes an extruded active carrier in honeycomb form having a first SCR catalytically active component and with a plurality of channels through which the exhaust gas flows during operation, and a washcoat coating having a second SCR catalytically active component being applied to the extruded body, wherein the first SCR catalytically active component and the second SCR catalytically active component are each independently one of: (i) vanadium catalyst with vanadium as catalytically active component; (ii) mixed-oxide catalyst with one or more oxides, in particular those of transition metals or lanthanides as catalytically active component; and (iii) an Fe- or a Cu-zeolite catalyst.

A catalytically active material is provided. The material includes a mixed oxide having a first metal selected from group 4 of the periodic table of elements and/or a second metal, and at least one further metal selected from group 11 of the periodic table of elements, wherein the macroscopic composition of the material given by the chemical formula corresponds to the composition of the material at a molecular level. A coating made of such a material is also provide, as is an article having such a coating, and a method for producing such a material.

The present disclosure relates to a substrate containing passive NO.sub.x adsorption (PNA) materials for treatment of gases, and washcoats for use in preparing such a substrate. Also provided are methods of preparation of the PNA materials, as well as methods of preparation of the substrate containing the PNA materials. More specifically, the present disclosure relates to a coated substrate containing PNA materials for PNA systems, useful in the treatment of exhaust gases. Also disclosed are exhaust treatment systems, and vehicles, such as diesel or gasoline vehicles, particularly light-duty diesel or gasoline vehicles, using catalytic converters and exhaust treatment systems using the coated substrates.

The exhaust gas purification device includes: a substrate of wall flow structure having inlet cells, outlet cells and a porous partition wall; and a catalyst layer provided in at least part of internal pores of the partition wall and held on the surface of the internal pores. The relationship between an average filling factor A of the catalyst layer held in pores having a pore diameter of 5 m to less than 10 m, an average filling factor B of the catalyst layer held in pores having a pore diameter of 10 m to less than 20 m and an average filling factor C of the catalyst layer held in pores having a pore diameter of 20 m to less than 30 m, among the internal pores of the partition wall 16 in which the catalyst layer is held, satisfies the following expression: A<B<C.

Methods and systems are provided for a diesel oxidation catalyst. In one example, the diesel oxidation catalyst comprises a washcoat with different catalytically active portions for reacting with one or more of carbon containing compounds and NO.sub.x. The diesel oxidation catalyst is located upstream of a particulate filter in an exhaust passage.

Methods and systems are provided for a diesel oxidation catalyst. In one example, the diesel oxidation catalyst comprises a washcoat with different catalytically active portions for reacting with one or more of carbon containing compounds and NO.sub.x. The diesel oxidation catalyst is located upstream of a particulate filter in an exhaust passage.

Disclosed in certain embodiments is a catalytic material comprising: an active precious metal component comprising platinum; a sulfur-tolerant support material comprising silica on zirconia; and a substrate having the catalytic material coated thereon.

Provided is an exhaust purification device which is provided in the exhaust passage of an internal combustion engine and purifies the exhaust gas of the internal combustion engine, the exhaust purification device including: a metal support having a flow path in which the exhaust gas flows; and a catalyst layer formed on a surface of the metal support, in which the catalyst layer includes a noble metal, and a metal having a different crystal structure than the noble metal.

A process for preparing a catalyst material, includes the steps of: (a) providing a support material having surface hydroxyl (OH) groups, wherein the support material is ceria (CeO.sub.2), zirconia (ZrO.sub.2) or a combination of thereof; (b) reacting the support material having surface hydroxyl (OH) groups of step (a) with a precursor containing two transition metal atoms, each chosen independently from the group consisting of: W, Mo, Cr, Ta, Nb, V, Mn; (c) calcining the product obtained in step (b) in order to provide a catalyst material showing dual site surface species containing pairs of transition metal atoms derived from the precursor that are present in oxide form on the support material. Additionally, a catalyst material is obtained by the process set out above, and the catalyst material is used as an ammonia selective catalytic reduction (NH.sub.3-SCR) catalyst for nitrogen oxides (NOx) reduction.