An exhaust gas purifier is disposed in an exhaust gas passage of an engine, and includes: a DPF for capturing PM contained in exhaust gas; an SCR catalyst provided downstream of the DPF in a direction of flow of the exhaust gas, and for reducing NO.sub.x contained in the exhaust gas for purification in the presence of NH.sub.3; an inj ection unit provided between the DPF and the SCR catalyst, and for supplying urea to the SCR catalyst so as to supply NH.sub.3 to the SCR catalyst; and an AMOX provided downstream of the SCR catalyst in the direction of flow of the exhaust gas, and for removing NH.sub.3 having passed through the SCR catalyst. The DPF does not contain Pt or Pd, and contains Rh. The AMOX contains Pt.

Provided is a method of producing a zeolite film continuously and efficiently. The method of forming zeolite on a surface of a support is characterized in that the method includes: a first step of attaching zeolite fine crystals to a surface of a support; a second step of preparing synthetic gel for growing the fine crystals; a third step of putting the support and the synthetic gel into a continuous reactor and performing hydrothermal synthesis; and a fourth step of cleaning the support on which zeolite has been hydrothermally synthesized, and in the third step, the temperature, pressure, and flow of the synthetic gel in the continuous reactor is adjusted, the support is moved being immersed in the synthetic gel, the reaction time of the hydrothermal synthesis is adjusted by adjusting the time from when the support enters the continuous reactor to when the support exits the continuous reactor.

Described are catalytic articles comprising a substrate having a washcoat on the substrate, the washcoat containing a catalytic component having a first average (D50) particle size and a functional binder component having a second average (D50) particle size in the range of about 10 nm to about 1000 nm, wherein the ratio of the first average (D50) particle size to the second average (D50) particle size is greater than about 10:1. The catalytic articles are useful in methods and systems to purify exhaust gas streams from an engine.

A catalyst pellet has the shape of a column and has a cross-section having the shape of an ellipse in a direction perpendicular to an axis.

Provided herein is a catalytic article including a catalytic coating disposed on a substrate, wherein the catalytic coating comprises a bottom coating on the substrate and a top coating layer on the bottom coating layer, one such coating layer containing a platinum group metal on a refractory metal oxide support and the other such coating layer containing a ceria-containing molecular sieve. Such catalytic articles are effective toward treating exhaust gas streams of internal combustion engines and exhibit outstanding resistance to sulfur.

A phosphorus compound-containing exhaust gas purifying catalyst includes: a refractory three-dimensional structure extending from a gas inflow side end surface to a gas outflow side end surface, the refractory three-dimensional structure having cell walls that define and form multiple gas flow paths, the gas flow paths running from the gas inflow side end surface to the gas outflow side end surface; a lower catalyst layer that contains Pd and is formed continuously from the gas inflow side end surface on the cell walls; a gas inflow side upper catalyst layer that contains Rh and is located as an uppermost layer on the cell walls; and a gas outflow side upper catalyst layer that contains Rh and is located as an uppermost layer on the cell walls.

A plugged honeycomb segment includes a honeycomb segment having a quadrangular prism shape which includes porous partition walls arranged to surround a plurality of cells and an outermost circumferential wall, and a plugging portion, wherein a porosity of the partition walls is 30 to 70%, in a cross section orthogonal to the cell extending direction, an inflow cell surrounded by the partition walls is a hexagon, and an outflow cell is a square, one outflow cell is surrounded by four inflow cells, the cell located at the outermost circumference includes a complete cell and an incomplete cell, and a thickness of the outermost circumferential wall in contact with the incomplete cell (T1), a thickness of the outermost circumferential wall in contact with the complete cell (T2), and a thickness of the partition walls (WT), satisfy 0.200 mm<T1<T2(WT) and T20.700 mm.

Provided is a catalyst article for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The catalyst article has a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia.

An oxidation catalyst composite, methods, and systems for the treatment of exhaust gas emissions from a diesel engine are described. More particularly, described is an oxidation catalyst composite including a first oxidation component comprising a first refractory metal oxide support, palladium (Pd) and platinum (Pt); a NO.sub.x storage component comprising one or more of alumina, silica, titania, ceria, or manganese; and a second oxidation component comprising a second refractory metal oxide, a zeolite, and Pt. The oxidation catalyst composite is sulfur tolerant, adsorbs NOx and thermally releases the stored NO.sub.x at temperature less than 350 C.

A honeycomb structure includes a porous partition wall defining a plurality of cells, wherein the plurality of cells include a first cell and a second cell, on the partition wall disposed to surround the at least one first cell, a protrusion is each provided with, the first protrusion and the second protrusion are each disposed to at least partially overlap with each other on extended lines in extending directions of the respective protrusions, and an inter-protrusion length (X) of a distal end of the first protrusion and a distal end of the second protrusion is equal to or more than 10% and equal to or less than 70% with respect to a mutual distance (W) from the one part to the other part on the partition walls facing each other.