The present invention provides an exhaust gas purification catalyst provided with: a substrate of wall flow structure in which inlet cells and outlet cells are partitioned by porous partition walls; and a catalyst layer disposed at least inside the partition wall and including a catalyst body. The catalyst layer satisfies the following conditions: (1) the pore volume of pores no larger than 5 m, as measured in accordance with a mercury intrusion technique, is 24000 mm.sup.3 or greater per L of volume of the substrate; and (2) a permeability coefficient measured by a Perm porometer is 0.6 m.sup.2 to 4.4 m.sup.2.

The present disclosure generally provides catalysts, catalyst articles and catalyst systems including such catalyst articles. In particular, the catalyst composition includes a metal ion-exchanged molecular sieve ion-exchanged with at least one additional metal, which reduces the number of metal centers often present in metal promoted zeolite catalysts. Methods of making and using the catalyst composition are also provided, as well as emission treatment systems including a catalyst article coated with the catalyst composition. The catalyst article present in such emission treatment systems is useful to catalyze the reduction of nitrogen oxides in gas exhaust in the presence of a reductant while minimizing the amount of dinitrogen oxide emission.

A method for treating exhaust gas from an internal combustion engine including, determining if a steady state condition exist and perturbing a reductant injection corresponding the steady state. Measuring a first and a second NOx values corresponding to the steady state and resulting from the perturbation, and computing a gradient of the NO.sub.x values relative to the steady state respectively. The method also includes comparing the gradient of the second NO.sub.x value with one of the first NO.sub.x value, if the gradient of the first NOx value is within a selected range of the gradient of the second NOx value, identifying poor efficiency operation for the engine and setting an estimated reductant storage at zero. Otherwise if the gradient of the second NOx value exceeds a selected threshold, identifying a reductant slip condition and setting the estimated storage at maximum, if not, making no corrections in estimated storage.

Method for the preparation of a catalyst comprising vanadium pentoxide supported on a metal oxide catalyst carrier comprising the steps of a) providing particles of crystalline vanadium pentoxide and particles of a metal oxide catalyst carrier; b) solid state mixing the particles and dispersing the vanadium pentoxide particles on surface of the metal oxide carrier particles; and c) anchoring the dispersed vanadium pentoxide particles on surface of the metal oxide carrier particles by calcination at a temperature above 500? C., characterized in that sintering of the vanadium pentoxide particles is suppressed by addition of an anti-sintering metal oxide component, such as tungsten trioxide, during the anchoring in step c).

Filter bag assembly for use in cleaning of process gas comprising an outer filter bag and one or more inner filter bags separately arranged within the outer filter bag, and said one or more inner filter bags also separately arranged within each other, the one or more inner filter bags and the outer filter bags are provided with catalytically active material.

The present disclosure relates to a method for photocatalytic ozonation reaction, in which the silicon carbide material is used. By using the silicon carbide material for photocatalytic ozonation reaction, the present disclosure overcomes the problem of low photocatalytic efficiency of silicon carbide, utilizes photogenerated electrons therefrom with strong reducibility to reduce ozone molecules to efficiently produce hydroxyl radicals, so as to improve the oxidation capacity in the process. Whether visible light or ultraviolet light is coupled with ozone, the group has strong catalytic activity, moreover, the silicon carbide has low cost and good stability, which prolongs the life of catalyst for photocatalytic ozonation or device.

A porous ceramic substrate for use as a particle filter, with a porosity of at least 50%, which includes a non-uniform coating layer of an oxide component in contact with a surface of the ceramic substrate, which oxide component is distributed on the surface and in dead-end pores of the ceramic substrate and creates the non-uniform coating layer on the substrate support, wherein the coating layer has a substantially smooth surface. Such substrate is typically a particle filter or part of a particle filter, e.g. a DPF.

A system for use in selective catalytic reduction reactor is disclosed. The system may include a catalyst bed and a screen located close to the catalyst bed in a manner so that flow of flue gas to the catalyst bed contacts the screen before it contacts the catalyst bed. The screen may be adapted to support a weight of at least 400 pounds above the catalyst bed so that the weight is not imposed on the catalyst. The screen may have a plurality of holes across its surface in a manner so that the screen is adapted to change the velocity distribution of the flue gas as it flows through the screen.

Provided is a catalyst composition for treating exhaust gas comprising a blend of a first component and second component, wherein the first component is an aluminosilicate or ferrosilicate molecular sieve component wherein the molecular sieve is either in H+ form or is ion exchanged with one or more transition metals, and the second component is a vanadium oxide supported on a metal oxide support selected from alumina, titania, zirconia, cella, silica, and combinations thereof. Also provided are methods, systems, and catalytic articles incorporating or utilizing such catalyst blends.

Method for the preparation of a honeycomb catalyst including the steps of pre-coating a non-woven fibrous sheet, corrugating the fibrous sheet and rolling-up or stacking-up the corrugated sheet to form a honeycomb body. The honeycomb body is subsequently washcoated, including the addition of at least one catalytically active compound.