JP-2021517508-A5 -

Dates

Publication Date

20230526

Application Date

20190322

Description

In a further embodiment, a method for producing a catalyst article using the catalyst article of the present invention is provided, the method comprising : impregnating the first surface of one or more channels of a catalytically active substrate formed of an extruded vanadium-containing SCR catalyst material with an aqueous salt solution of copper, iron, cerium, magnesium, or zirconium, or a mixture of two or more of these; drying the impregnated substrate; and applying a wash coat of an ammonia slip catalyst composition containing one or more platinum group metals supported on a particulate metal oxide carrier material to the first surface, thereby arranging a first layer including the wash coat of an ammonia slip catalyst composition containing one or more platinum group metals supported on a particulate metal oxide carrier material to the first surface. To avoid any ambiguity, the entire contents of all documents found herein are incorporated herein by reference. The disclosures in this specification may include the following aspects: (Aspect 1) A catalytic article for treating the flow of combustion exhaust gas, wherein the article is A catalytically active substrate comprising one or more channels extending along its axial length, wherein combustion exhaust gas flows through the channels during use, and the one or more channels have a first surface for contact with the flow of combustion exhaust gas, The substrate is formed from an extruded vanadium-containing SCR catalyst material. The first layer is disposed on at least a portion of the first surface, and the first layer comprises a wash coat of an ammonia slip catalyst composition containing one or more platinum group metals supported on a particulate metal oxide carrier material. A layer comprising a wash coat of the SCR catalyst composition is disposed on the surface of one or more channels. A catalyst article wherein at least a portion of the first surface on which the first layer is disposed contains a compound of copper, iron, cerium, or zirconium, or a mixture of two or more of these. (Aspect 2) The catalyst article according to embodiment 1, wherein the compound is an iron compound. (Aspect 3) The catalyst article according to embodiment 1 or 2, wherein the layer including the wash coat of the SCR catalyst composition is the first layer disposed on at least a portion of the first surface, and the first layer is a mixture of the SCR catalyst composition and the ammonia slip catalyst composition. (Aspect 4) The catalyst article according to embodiment 1 or 2, wherein the layer containing the wash coat of the SCR catalyst composition is a second layer disposed on at least a portion of the first layer. (Aspect 5) The catalyst article according to embodiment 1, 2, 3, or 4, wherein the substrate is a honeycomb flow-through monolith substrate. (Aspect 6) The catalyst article according to any one of embodiments 1 to 5, wherein the particulate metal oxide support material is selected from the group consisting of alumina, silica-titania mixed oxide, Ce-Zr mixed oxide, ceria, titania, silica, zirconia, and zeolite, or a mixture of two or more of these. (Aspect 7) The catalyst article according to any one of embodiments 1 to 6, wherein the substrate contains 1 to 3% by weight, preferably 1.5 to 2.5% by weight, of vanadium oxide. (Appendix 8) The catalyst article according to any one of embodiments 1 to 7, wherein the first layer contains 0.05 to 0.5% by weight of the platinum group metal. (Aspect 9) The catalyst article according to any one of embodiments 1 to 8, wherein the platinum group metal is Pt or a combination of Pt and Pd. (Aspect 10) The catalyst article according to any one of embodiments 1 to 9, wherein the first layer covers up to 50% of the axial length of the substrate, preferably 10 to 40% of the axial length, and preferably extends from the end of the article. (Aspect 11) The catalyst article according to embodiment 10, as an accessory to embodiment 4, wherein the second layer covers at least 50%, preferably 100%, of the axial length of the substrate. (Aspect 12) The catalyst article according to any one of embodiments 1 to 9, wherein the first layer covers at least 50%, preferably 100%, of the axial length of the substrate. (Aspect 13) The catalyst article according to any one of embodiments 1 to 12, wherein the SCR catalyst composition of the second layer comprises a copper-promoting zeolite, an iron-promoting zeolite, or a combination thereof. (Aspect 14) The catalyst article according to embodiment 13, wherein the SCR catalyst is a copper or iron-enhanced microporous zeolite having a skeletal structure of AEI, AFX, CHA, DDR, ERI, ITE, LEV, LTA, STI, or SFW. (Phenomenon 15) The catalyst article according to any one of embodiments 1 to 14, wherein the second layer has a maximum ammonia storage capacity of 0.1 g per gram of the second layer when measured at 200°C. (Aspect 16) The catalyst article according to Embodiment 4, and any one