This disclosure features an exhaust aftertreatment system that includes a selective catalytic reduction catalyst that includes a metal oxide catalyst and a metal zeolite catalyst, a metal oxide catalyst that is other than a vanadium oxide catalyst and a vanadium oxide catalyst, or a metal oxide catalyst that is other than a vanadium oxide catalyst together with a metal zeolite catalyst and a vanadium oxide catalyst. When used in a selective catalytic reduction system in a diesel engine, the catalyst composition can increase a conversion efficiency of nitrogen oxides (NOx) to nitrogen and water by a minimum of 2 percent compared to the metal zeolite catalyst alone, the metal oxide catalyst alone, or the vanadium oxide catalyst alone, when present.

The present disclosure describes a diesel oxidation catalyst, including a metal oxide including a metal on a metal oxide surface, and less than 10 g/ft.sup.3 by weight of Pt or Pd, wherein the diesel oxidation catalyst oxidizes carbon monoxide and hydrocarbons of a diesel exhaust to carbon dioxide and water.

Catalytic cores for a wall-flow filter include juxtaposed channels extending longitudinally between an inlet side and an outlet side of the core, wherein the inlet channels are plugged at the outlet side and outlet channels are plugged at the inlet side. Longitudinal walls forming the inlet and outlet channels separate the inlet channels from the outlet channels. The walls include pores that create passages extending across a width of the walls from the inlet channels to the outlet channels. Catalysts are distributed across the width and length of the walls within internal surfaces of the pores in a manner such that the loading of each catalyst across the width varies by less than 50% from an average loading across the width.

An oxidation catalyst for treating an exhaust gas from a diesel engine, which oxidation catalyst comprises: a first washcoat region comprising a first platinum group metal (PGM), a first support material and a NO.sub.x storage component; a second washcoat region comprising platinum (Pt), manganese (Mn) and a second support material; and a substrate having an inlet end and an outlet end.

The present invention addresses the problem and purpose of providing a honeycomb structure that has a sufficiently high strength and is excellent in endurance, and a catalyst for cleaning an exhaust gas using the same that is excellent in resistance to sulfur oxide (SOX). The honeycomb structure of the present invention is one consists of a flat inorganic fiber sheet comprising an inorganic fiber sheet having supported thereon an inorganic binder and zeolite, and a corrugated inorganic fiber sheet comprising an inorganic fiber sheet having supported thereon the same inorganic binder and zeolite, which are alternately combined with each other, wherein it is characterized in that the zeolite has a particle diameter (i.e., a median particle diameter, D50) of from 0.5 to 10.0 m.

Provided are a stainless steel foil and a catalyst carrier for an exhaust gas purifying device which uses the foil. Specifically, a stainless steel foil contains, in percent by mass, 0.05% or less of C, 2.0% or less of Si, 1.0% or less of Mn, 0.003% or less of S, 0.05% or less of P, more than 15.0% and less than 25.0% of Cr, 0.30% or less of Ni, 3.0% to 10.0% of Al, 0.03% to 1.0% of Cu, 0.10% or less of N, 0.02% or less of Ti, 0.02% or less of Nb, 0.02% or less of Ta, 0.005% to 0.20% of Zr, 0.03% to 0.20% of REM excluding Ce, 0.02% or less of Ce, 2.0% to 6.0% in total of at least one of Mo and W, and the balance being Fe and incidental impurities.

An exhaust gas purifying catalyst has enhanced NOx purification performance in a lean atmosphere, and a production method for producing an exhaust gas purifying catalyst includes sputtering a target material containing Ta and Rh to form composite fine metal particles respectively containing Ta and Rh.

An exhaust gas controlling catalyst includes zirconia particles; ceria particles which contact the zirconia particles, of which a mean particle size is smaller than a mean particle size of the zirconia particles; and an active metal that is supported on at least the ceria particles in a dispersed manner.

A catalyst for purification of exhaust gas, comprising a first catalyst comprising: a first catalyst support comprising a first composite oxide composed of alumina, zirconia, and titania, and ceria supported on a surface of the first composite oxide in an amount of 0.5 to 10 parts by mass relative to 100 parts by mass of the first composite oxide; and a first noble metal supported on a surface of the first catalyst support in an amount of 0.05 to 5.0 parts by mass in terms of metal relative to 100 parts by mass of the first catalyst support.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, an ammonia source, and a first ammonia injector in fluid communication with the ammonia source. The first ammonia injector is configured to inject ammonia into the exhaust gas pathway at a first rate. The exhaust gas treatment system also includes a first treatment element positioned downstream of the first ammonia injector and a second ammonia injector in fluid communication with the ammonia source and positioned downstream of the first treatment element. The second ammonia injector is configured to inject ammonia into the exhaust gas pathway at a second rate different from the first rate. The exhaust gas treatment system further includes a second treatment element positioned downstream of the second ammonia injector.