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−(½×WT) and T2≤0.700 mm.

A honeycomb filter includes a honeycomb structure having a porous partition wall disposed to surround a plurality of cells; and a plugging portion provided at one end of the cell, wherein the honeycomb structure has an inflow side region including a range of up to at least 30% with respect to the total length of the honeycomb structure with the inflow end face as the starting point and an outflow side region including a range of up to at least 20% with respect to the total length of the honeycomb structure with the outflow end face as the starting point, in the extending direction of the cell of the honeycomb structure, an average pore diameter of the partition wall in the inflow side region is 9 to 14 μm and an average pore diameter of the partition wall in the outflow side region is 15 to 20 μm.

An oxidation catalyst composite for abatement of exhaust gas emissions from a lean burn engine is provided, the catalyst composite including a carrier substrate having a length, an inlet end and an outlet end, and an oxidation catalyst material coated on the carrier substrate. The oxidation catalyst material can include a first layer and a second layer. The first layer can include a first oxygen storage component that includes ceria and is impregnated with a palladium (Pd) component and a second component including one or more of magnesium (Mg), rhodium (Rh), and platinum (Pt). The second layer can include a refractory metal oxide component impregnated with platinum (Pt) and palladium (Pd), wherein the ratio of Pt to Pd is in the range of about 0:10 to about 10:0.

Described is a selective catalytic reduction material comprising a spherical particle including an agglomeration of crystals of a molecular sieve. The catalyst is a crystalline material that is effective to catalyze the selective catalytic reduction of nitrogen oxides in the presence of a reductant at temperatures between 200° C. and 600° C. A method for selectively reducing nitrogen oxides and an exhaust gas treatment system are also described.

[Problem] Provided is an exhaust gas purification catalyst capable of exhibiting even higher exhaust gas purification performance without impairing Pd catalytic activity, and an exhaust gas purification system using the exhaust gas purification catalyst.

[Solution] Provided is an exhaust gas purification catalyst comprising a substrate and a catalyst layer provided on the substrate, said catalyst having a first section located upstream along a flow direction of the exhaust gas and a second section located downstream from the first section; the catalyst layer in the first section comprises a first catalyst layer comprising palladium and a second catalyst layer comprising rhodium and covering the first catalyst layer, wherein a pore volume proportion is 12% or more and less than 18% wherein the pore volume proportion is a proportion of a total volume of the pores, which have a pore diameter of 0.06 μm to 30.0 μm as measured by mercury press-in method and existing in the substrate and the catalyst layer in the first section to a volume of a entire first section; and a wash coat amount is 100 g/L to 190 g/L, wherein a wash coat amount is a mass per unit volume of the catalyst layer in the first section to the volume of the substrate existing in the first section.

The invention describes a process for the photocatalytic reduction of carbon dioxide carried out in the liquid phase and/or in the gas phase under irradiation employing a photocatalyst of microporous crystalline metal sulfide type, said process being carried out by bringing a charge containing the CO.sub.2 and at least one sacrificial compound into contact with said photocatalyst, then by irradiating the photocatalyst by at least one irradiation source producing at least one wavelength lower than the bandgap width of said photocatalyst, so as to reduce the CO.sub.2 and to oxidize the sacrificial compound, so as to produce an effluent containing, at least in part, C.sub.1 or more carbon-based molecules other than CO.sub.2.

The present invention relates generally to the field of exhaust treatment systems for purifying exhaust gas discharged from a lean burn engine. The exhaust treatment system comprises a Diesel Oxidation Catalyst (DOC), a Catalyzed Soot Filter (CSF), a reductant injector, an AEI zeolite based Selective Catalyzed Reduction (SCR) catalyst and an Ammonia Oxidation Catalyst (AMOX) downstream to the AEI zeolite based SCR catalyst.

It is an object to provide a catalyst that can effectively purify exhaust gas, in particular, carbon monoxide (CO) in exhaust gas, emitted from a diesel engine, a production method therefor, and an exhaust gas purification method using the same. A diesel engine exhaust gas purification catalyst for purifying exhaust gas emitted from a diesel engine of the present invention comprises a precious metal and alumina and/or zeolite supported on a three-dimensional structure, and has peaks for not less than three different pore sizes in a pore size distribution measured by the mercury intrusion method, wherein one of the peaks is a peak 2 at a pore size of not less than 0.3 μm and less than 1.0 μm, and the pore volume of the peak 2 being greater than 3.1% of the total pore volume.

The present invention relates to a process for the preparation of a catalyst for selective catalytic reduction comprising • (i) preparing a mixture comprising a metal-organic framework material comprising an ion of a metal or metalloid selected from groups 2-5, groups 7-9, and groups 11-14 of the Periodic Table of the Elements, and at least one at least monodentate organic compound, a zeolitic material containing a metal as a non-framework element, optionally a solvent system, and optionally a pasting agent, • (ii) calcining of the mixture obtained in (i); and further relates to a catalyst per se comprising a composite material containing an amorphous mesoporous metal and/or metalloid oxide and a zeolitic material, wherein the zeolitic material contains a metal as non-framework element, as well as to the use of said catalyst.

A porous material includes an aggregate, and a binding material that binds the aggregate together in a state where pores are formed. The porous material contains 0.1 to 10.0 mass % of an MgO component, 0.5 to 25.0 mass % of an Al.sub.2O.sub.3 component, and 5.0 to 45.0 mass % of an SiO.sub.2 component with respect to the mass of the whole porous material, and further contains 0.01 to 5.5 mass % of an Sr component in terms of SrO.