Selective catalytic reduction catalyst and catalyst article containing the same

Abstract

The present invention relates to a selective catalytic reduction (SCR) catalyst comprising a support, vanadium, and antimony, a catalyst article comprising the SCR catalyst, and an exhaust treatment system for an internal combustion engine comprising the SCR catalyst. In one embodiment, the present invention provides an SCR catalyst for reducing nitrogen oxides, comprising a support and an active material on the support, wherein the support is present in the SCR catalyst in an amount of 40 to 99 mass % calculated as its oxide, based on the total mass of the SCR catalyst, the active material comprises vanadium and antimony, the vanadium is present in the SCR catalyst in an amount of 1 to 15 mass % calculated as V2O5, based on the total mass of the SCR catalyst, and the antimony is present in the SCR catalyst in an amount of 0.5 to 20 mass % calculated as Sb2O3, based on the total mass of the SCR catalyst, and the SCR catalyst is maintained at a temperature of 60,000 h. -1 It has a denitration efficiency at 200-300°C of at least 60% after hydrothermal aging at 550°C for 100 hours with 10% water at a space velocity of 0.15 and a 1:1 ammonia to NOx molar ratio.

Description

[Technical Field]

[0001] The present invention relates to a selective catalytic reduction (SCR) catalyst comprising a carrier, vanadium, and antimony, a catalytic article comprising this SCR catalyst, and an exhaust gas treatment system for an internal combustion engine comprising this SCR catalyst. [Background technology]

[0002] Nitrogen oxides, also known as NOx, released as exhaust gases from mobile sources such as automobiles and stationary sources such as power plants, are harmful to the environment and human health. To remove NOx from exhaust gases, catalytic reduction methods have been developed. Catalytic reduction methods are suitable for processing large volumes of exhaust gases, and selective catalytic reduction (SCR) is a method of converting NOx to nitrogen (N2) and water (H2O) with the help of an SCR catalyst in the presence of a reducing agent source. The reducing agent source can be hydrocarbons, ammonia, or urea, which are present in the exhaust gases of diesel engines or added to the exhaust gas flow of diesel engines. Of these, the reducing agent source is usually automotive-grade urea, also known as diesel exhaust fluid (DEF). Urea undergoes a hydrolysis reaction (urea + water produces ammonia and carbon dioxide), supplying ammonia to the exhaust flow. Processes involving the selective catalytic reduction of NOx to N2 by adding ammonia (or urea) as a reducing agent have been reported to be superior. Various catalysts useful for selective catalytic reduction, also known as SCR catalysts, have been developed to reduce NOx from both stationary and mobile sources. SCR catalysts need to reduce NOx over a wide temperature range, especially at the lowest possible temperatures below 300°C.

[0003] Among the various SCR catalysts, catalysts containing vanadium oxide as an active species (V SCR catalysts) have attracted particular attention due to their low cost and sulfur resistance during NOx reduction processes. Generally, V SCR catalysts contain one or more accelerators to improve catalytic performance. For example, V SCR catalysts containing tungsten or molybdenum oxide as accelerators have been widely studied for several decades, as described in US3279884A, EP0272620A2, EP0348768A2, CA289929A, CN103736497A, US7507684B2, US2014 / 0157763A1, WO2010 / 099395A1, WO2013 / 179129A2, and WO2013 / 017873A1.

[0004] To further reduce costs and improve catalytic performance for NOx reduction, V SCR catalysts with alternative accelerators are being developed. One alternative accelerator that is attracting attention is antimony. Such V SCR catalysts containing antimony as an accelerator are described, for example, in KR101065242B1, US2009 / 143225A1, and WO2017101449A1.

[0005] KR101065242B1 discloses a V SCR catalyst prepared by a method comprising mixing a vanadium precursor and an antimony precursor in a slurry containing a TiO2 sol, and calcining the resulting slurry at a temperature of 500°C or lower. It is stated that the V SCR catalyst having antimony as an accelerator has good NOx reduction efficiency and resistance to sulfur toxicity at low temperatures.

[0006] US2009 / 143225A1 discloses a V SCR catalyst comprising a metal oxide support, vanadium as an active substance, and antimony as an accelerator. This V SCR catalyst is prepared by impregnating TiO2 with a precursor containing vanadium and antimony, or by conventional catalyst synthesis methods such as the sol-gel method. This V SCR catalyst is described as being able to promote the reduction of NOx at low temperatures and enhance resistance to sulfur toxicity.

[0007] WO2017101449A1 discloses an SCR catalyst prepared from a process that includes mixing vanadium / antimony oxide and optionally a silicon source with a carrier containing TiO2 in a solvent to obtain a suspension, drying it, and calcining it. The vanadium / antimony oxide is prepared by providing a suspension containing vanadium oxide(s) and antimony oxide(s) and drying it.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Patent Document 10

Patent Document 11

Patent Document 12

Patent Document 13

Summary of the Invention

Means for Solving the Problems

[0009] The present invention relates to a selective catalytic reduction (SCR) catalyst containing a carrier, vanadium, and antimony.

[0010] Aspects include an SCR catalyst for reducing nitrogen oxides, including a carrier and an active substance on the carrier.

[0011] Other aspects include a method for preparing an SCR catalyst, a method for treating exhaust gas from an internal combustion engine, and a method for testing NOx.

[0012] Other aspects include an SCR catalyst article containing an SCR catalyst and an exhaust gas treatment system for an internal combustion engine.

Mode for Carrying Out the Invention

[0013] Before explaining some exemplary embodiments of the present invention, it should be understood that the present invention is not limited to the details of the configurations or method steps shown in the following description. The present invention can have other embodiments and can be implemented or executed in various ways.

[0014] Regarding the terms used in this disclosure, the following definitions are provided.

[0015] Throughout this specification, including the claims, the term "comprising" or "including" should be understood to be synonymous with the term "comprising at least one" unless otherwise specified, and "between" or "~" should be understood to include the limiting values.

[0016] The terms "a", "an", and "the" are used to refer to one or more (i.e., at least one) of the grammatical objects of the article.

[0017] The term "and / or" includes the meanings of "and", "or", and all other possible combinations of the elements connected to this term.

[0018] <00001All percentages and ratios are in terms of mass unless otherwise specified.

[0019] SCR catalyst The present invention relates to an SCR catalyst for reducing nitrogen oxides (NOx), comprising a carrier and an active substance on the carrier, wherein - The support material, calculated as its oxide, is present in the SCR catalyst in an amount of 40-99% by mass relative to the total mass of the SCR catalyst. - The active substance contains vanadium and antimony, with vanadium present in the SCR catalyst in an amount of 1 to 15% by mass relative to the total mass of the SCR catalyst, calculated as V2O5, and antimony present in the SCR catalyst in an amount of 0.5 to 20% by mass relative to the total mass of the SCR catalyst, calculated as Sb2O3. - SCR catalyst, 60,000h -1 With a space velocity and a molar ratio of ammonia to NOx of 1:1, hydrothermal aging at 550°C for 100 hours using 10% water results in a denitrification efficiency of at least 60% at 200-300°C.

[0020] In one or more embodiments, the SCR catalyst lasts for 60,000 hours. -1 After thermal aging at 600°C for 50 hours with a space velocity and a molar ratio of ammonia to NOx of 1:1, it has a denitrification efficiency of at least 50% at 200-300°C.

[0021] In one or more embodiments, the support may be a metal oxide of Ti, Si, W, Al, Ce, Zr, Mg, Ca, Ba, Y, La, Pr, Nb, Mo, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sn, Bi, or any mixture of two or more of these oxides. Alternatively, the support may further include a molecular sieve. The molecular sieve may be a silicate zeolite, an aluminosilicate zeolite, a metal-substituted aluminosilicate zeolite, or a non-zeolite molecular sieve.

[0022] In some embodiments, at least a portion of the above-mentioned metal oxides in the carrier can also function as additives such as binders, dispersants, fillers, stabilizers, and accelerators.

[0023] The amount of additives depends on the form of the finished catalyst. The amount of additives is expressed as the sum of each type of oxide incorporated into the SCR catalyst, and is generally in the range of 1 to 30% by mass, preferably 1 to 15% by mass, when the finished SCR catalyst is in the form of a coated substrate as described later, and generally in the range of 1 to 90% by mass, preferably 5 to 60% by mass, and more preferably 10 to 50% by mass, when the finished catalyst is in the form of a molded body. When two or more additives are used, the amount of each additive is not important for the purpose of the present invention.

[0024] In some embodiments, the support comprises at least one of TiO2, SiO2, WO3, CeO2, Al2O3, and ZrO2. In certain embodiments, the support comprises TiO2 and / or SiO2. In even more certain embodiments, the support comprises TiO2 and SiO2, wherein SiO2 is present in an amount of 1 to 20% by mass, preferably 2.5 to 15% by mass, and more preferably 3 to 10% by mass, relative to the total mass of the support.

[0025] In some embodiments, the support consists of TiO2, TiO2 and SiO2, TiO2 and WO3, TiO2, SiO2 and WO3, TiO2 and CeO2, TiO2, WO3 and CeO2, TiO2 and Al2O3, or TiO2 and ZrO2. The TiO2 used in the present invention may be commercially available or prepared by conventional methods known in the art. In certain embodiments, the TiO2 used in the present invention is in the form of anatase.

[0026] In a more specific embodiment, where SiO2 is used as the support and the completed catalyst is coated onto a substrate, the amount of SiO2 is in the range of 1 to 20% by mass, preferably 2.5 to 15% by mass, and more preferably 3 to 10% by mass, relative to the total mass of the support.

[0027] In some embodiments, the molecular sieve has the structural type AFG, AST, DOH, FAR, FRA, GIU, LIO, LOS, MAR, MEP, MSO, MTN, NON, RUT, SGT, SOD, SVV, TOL, UOZ, ABW, ACO, AEI, AEN, AFN, AFT, AFV, AFX, ANA, APC, APD, ATN, ATT, AT V, AVL, AWO, AWW, BCT, BIK, BRE, CAS, CDO, CHA, DDR, DFT, EAB, EDI, EEI, EPI, ERI, ESV, ETL, GIS, GOO, IFY, IHW, IRN, ITE, ITW, JBW, JNT, JOZ, JSN, KFI, LEV, -LIT, LTA, LTJ, LTN, MER, MON, MTF, MWF , NPT, NSI, NSOWE, PAU, TSC, RHO, RTH, PHR, SAS, SBV, SAUFN, SAVE, SUI, UGI, ZOI, CHI, LOV, NAB, N AT, RSN, STT, VSV, FER, MEL, MFI, MTT, MWW, SZR, AFI, AFR, AFS, AFY, ASV, ATO, ATS, BEA, BEC, BOG, BPH, CAN, CON, CZP, DFO, EMT, EON, EZT, FAU, GME, GON, IFR, ISV, IWR, IWV, IWW, LTL, MAZ, MEI, MOR , MOZ, MSE, MTW, NPO, OFF, OSI, -RON, RWY, SAO, SBE, SBS, SBT, SFE, SFO, SOS, SSY, USI or VET.

[0028] In one or more embodiments, the support, calculated as a metal oxide or molecular sieve, is present in the SCR catalyst in an amount of 50 to 90% by mass, preferably 60 to 85% by mass, including 65% by mass, 70% by mass, 75% by mass, and 80% by mass, relative to the total mass of the SCR catalyst.

[0029] In one or more embodiments, vanadium is present in the SCR catalyst in an amount of 4 to 12 mass%, preferably 5 to 10 mass%, calculated as V2O5, including 6 mass%, 7 mass%, 8 mass%, and 9 mass%, relative to the total mass of the SCR catalyst.

[0030] In one or more embodiments, antimony is present in the SCR catalyst in an amount of 3 to 16 mass%, preferably 4 to 14 mass%, calculated as Sb2O3, including 5 mass%, 6 mass%, 7 mass%, 8 mass%, 9 mass%, 10 mass%, 11 mass%, 12 mass%, and 13 mass%, relative to the total mass of the SCR catalyst.

[0031] In one or more embodiments, vanadium and antimony are present in molar ratios V / Sb in the range of 8:1 to 1:8, preferably 4:1 to 1:4, and more preferably 2:1 to 1:2, calculated as individual elements.

[0032] In one or more embodiments, the SCR catalyst further comprises a platinum group metal (PGM). In some embodiments, the PGM is selected from the group consisting of platinum (Pt), palladium (Pd), rhodium (Rh), and mixtures thereof. It should be understood that these terms encompass not only the metallic form of these PGMs but also any metal oxide form that is catalytically active for reducing exhaust gases. Combinations of metallic and catalytically active metal oxide forms are also contemplated by the present invention.

[0033] Method for preparing an SCR catalyst The present invention also involves the following steps: 1) Adding an antimony precursor to DI water and stirring at a temperature in the range of 50 to 150°C to obtain an antimony suspension, 2) Adding a vanadium precursor to the antimony suspension obtained in step 1), stirring at a temperature in the range of 50 to 150°C to obtain an active substance suspension, 3) A step of drying the suspension of active substances at a temperature in the range of 80 to 300°C to obtain an active substance containing vanadium and antimony, 4) A step of mixing the active substance with the support in a solvent. This invention provides a method for preparing an SCR catalyst, including [a specific component].

[0034] In the context of the present invention, vanadium precursors and antimony precursors are intended to mean vanadium-containing compounds and antimony-containing compounds that are converted to vanadium species and antimony species, respectively, such as metal oxides, complex oxides, salts, sulfates, phosphates, vanadates, and antimonates.

[0035] Typical vanadium precursors can be at least one of ammonium vanadate, vanadium oxalate, vanadyl oxalate, vanadium oxide (e.g., vanadium pentoxide), vanadium monoethanolamine, vanadium chloride, vanadium trichloride oxide, vanadyl sulfate, vanadium sulfate, vanadium antimonite, vanadium antimonate, and vanadium oxide.

[0036] Typical antimony precursors can be at least one of the following: antimony acetate, antimony glycol (antimony ethylene glycoside), antimony sulfate, antimony nitrate, antimony chloride, antimony trisulfide, antimony oxide (e.g., Sb2O3), and antimony vanadate.

[0037] In one or more embodiments, the drying in step 3) is preferably carried out at a temperature in the range of 100°C to 250°C, more preferably 110°C to 180°C. This drying can be carried out by any method known in the art, without particular limitations.

[0038] In one or more embodiments, the mixture from step 4), which may be dry or wet, may be prepared by various methods known in the art, depending on the precursor used in this step. For example, a wet mixture may be prepared by an incipient wetness impregnation technique, also known as capillary impregnation or dry impregnation. In a particular embodiment, a wet mixture is prepared by a method comprising preparing a mixture of a carrier and Sb2O3, and then incorporating a solution of a vanadium precursor by incipient wetness impregnation.

[0039] SCR catalyst articles The present invention also provides an SCR catalyst article comprising the above-mentioned SCR catalyst, wherein the SCR catalyst is applied on a substrate having a monolithic structure.

[0040] The substrate is not particularly limited and includes, for example, flow-through substrates or wall-flow substrates. The substrate may be any material commonly used in the preparation of such catalysts, such as ceramics or metals, and preferably has a ceramic honeycomb structure. Any suitable substrate can be employed, for example, a monolithic substrate (i.e., a flow-through substrate) of the type having fine parallel gas flow channels extending from the inlet or outlet surface of the substrate so that the channels are open to the fluid flowing through it. The channels, which are essentially straight paths from the fluid inlet to the fluid outlet, are defined by walls to which the catalyst material is applied as a wash coat so that the gas flowing through the channels comes into contact with the catalyst material. The flow channels of the monolithic substrate are thin-walled channels and can have any suitable cross-sectional shape and size, such as trapezoidal, rectangular, square, sinusoidal, hexagonal, elliptical, or circular.

[0041] Such monolithic substrates may contain up to approximately 900 or more channels (or "cells") per square inch of cross-section, but a much smaller number may be used. For example, a substrate may have approximately 50 to 600 cells ("cpsi") per square inch, more typically approximately 200 to 600, and most typically approximately 300 to 600.

[0042] In some embodiments, the amount of SCR catalyst supported on the substrate is generally 0.5 to 10 g / in. 3 Preferably 1-7 g / in 3 More preferably 2-5.5 g / in 3 It is within the range of [the specified range].

[0043] Alternatively, the SCR catalyst may be molded into beads, spheres, pellets, or honeycomb structures, etc., according to various techniques known in the art. Any conventional additives, such as binders, fillers, and / or plasticizers, may be incorporated into the molding process as desired. It should be understood that the molded bodies are dried and calcined for use.

[0044] In one or more embodiments, the SCR catalyst is formed into a honeycomb by extrusion, dried, and calcined to provide a finished catalyst in the form of an extruded honeycomb. Such a catalyst in the form of an extruded honeycomb contains the catalyst material itself as a framework without the need for an additional inert substrate. By not using an inert substrate, the amount of catalyst material per unit volume of the catalyst is significantly increased, and therefore, compared to a finished catalyst in the form of a coated substrate, it is possible to provide better NOx reduction performance, especially at low temperatures.

[0045] In some embodiments, the extruded SCR catalyst article further comprises at least one binder and / or matrix material and / or its precursor. The binder and / or matrix component can improve the mechanical strength of the final extruded product. The binder and / or matrix material can be selected from, but is not limited to, cordierite, nitrides, carbides, borides, intermetallic compounds, aluminosilicates, spinel, alumina and / or doped alumina, silica, titania, zirconia, titania-zirconia, glass fibers and any two or more mixtures thereof.

[0046] In some embodiments, the extruded SCR catalyst article may be prepared by a process that allows for the addition of additives such as plasticizers and / or dispersants and / or acids and / or pore-forming agents.

[0047] In a particular embodiment of an extruded SCR catalyst article having a matrix material, vanadium is present in the extruded SCR catalyst article in an amount of 0.5 to 15% by mass relative to the total mass of the extruded SCR catalyst article, calculated as V2O5.

[0048] In a particular embodiment of an extruded SCR catalyst article having a matrix material, antimony is present in the extruded SCR catalyst article in an amount of 0.25 to 20% by mass relative to the total mass of the extruded SCR catalyst article, calculated as Sb2O3.

[0049] In some embodiments, the SCR catalyst on a substrate, or the extruded SCR catalyst, is then dried at a temperature in the range of -20°C to 300°C, preferably 20°C to 250°C, more preferably 20°C to 200°C. Drying can be carried out by any method known in the art, without particular limitations.

[0050] In some embodiments, the SCR catalyst on a substrate or the extruded SCR catalyst is further calcined after drying at a temperature in the range of 350°C to 700°C, preferably 400°C to 700°C, and more preferably 450°C to 600°C, including 500°C and 550°C.

[0051] Generally, firing is carried out for 5 hours or less, particularly 3 hours or less, for example 0.5, 1, or 2 hours, when the finished catalyst is in the form of a coated substrate, and for 20 hours or less, particularly 10 hours or less, for example 1, 2, 3, 4, 5, 6, 7, 8, or 9 hours, when the finished catalyst is in the form of a molded body.

[0052] Methods for treating exhaust gases from internal combustion engines In a further embodiment, the present invention is (1) Using the above SCR catalyst, (2) Exhaust gas from the engine is passed through this SCR catalyst, (3) The above is carried out in the presence of a reducing agent. Regarding methods for treating exhaust gases from internal combustion engines.

[0053] The exhaust gas that can be treated by the SCR catalyst according to the present invention is any exhaust gas containing NOx to be removed or reduced. The exhaust gas may be, but is not limited to, an internal combustion engine such as a lean-burn engine, diesel engine, natural gas engine, power plant, incinerator, generator set, or gasoline engine.

[0054] In one or more embodiments, the exhaust gas is brought into contact with the SCR catalyst according to the present invention at temperatures in the range of 150°C to 650°C, or 170°C to 625°C, or 180°C to 600°C, or 200°C to 550°C, including 250°C, 300°C, 350°C, 400°C, 450°C, and 500°C.

[0055] The contact between the exhaust gas and the SCR catalyst according to the present invention is carried out in the presence of a reducing agent. The reducing agent that can be used in the present invention may be any reducing agent known in the art for reducing NOx, such as NH3. The NH3 may be derived from urea.

[0056] NOx conversion rate testing method In a further embodiment, the present invention relates to a method for testing the NOx conversion rate, comprising contacting an exhaust gas containing NOx with a reducing agent in the presence of the above-mentioned SCR catalyst, wherein the method selectively reduces at least a portion of the NOx to N2 and H2O.

[0057] Exhaust treatment system In a further embodiment, the present invention relates to an exhaust treatment system for an internal combustion engine comprising a reducing agent injector and the above-mentioned SCR catalyst.

[0058] In one or more embodiments, the exhaust treatment system further includes at least one catalyst selected from diesel oxidation catalysts (DOCs), catalytic soot filters (CSFs), and ammonia oxidation catalysts (AMOx).

[0059] Oxidation catalysts containing one or more precious metals, such as platinum group metals (PGMs), dispersed on refractory metal oxide supports such as alumina are known to be used in the exhaust treatment of diesel engines to convert gaseous pollutants, both hydrocarbons and carbon monoxide, into carbon dioxide and water by catalyzing their oxidation. Such catalysts are generally contained in a unit called a diesel oxidation catalyst (DOC), which is placed in the exhaust flow path from the diesel engine to treat the exhaust before it is released into the atmosphere. Typically, diesel oxidation catalysts are formed on a ceramic or metal substrate on which one or more catalytic coating compositions are deposited. In addition to converting gaseous HC and CO emissions and particulate matter (SOF portion), oxidation catalysts containing one or more PGMs promote the oxidation of NO to NO2.

[0060] As used herein, the term "DOC" refers to a diesel oxidation catalyst that controls HC and CO emissions from diesel vehicles. A DOC catalyst mainly contains PGM, alumina, zeolite, and titania on a ceramic or metal substrate, preferably Pt and / or Pd, alumina and / or titania, and optionally silica as an additive on a ceramic or metal substrate.

[0061] In addition to the use of DOC catalysts, particulate filters are used in exhaust gas treatment systems to achieve a high reduction in particulate matter. Known filter structures for removing particulate matter from exhaust gases include honeycomb wall flow filters, wound or packed fiber filters, open-cell foam filters, and sintered metal filters. These filters can remove more than 90% of particulate matter from exhaust gases.

[0062] In some embodiments, the soot filter is coated with a catalyst to promote soot combustion and thereby promote filter regeneration. In one or more embodiments, the soot filter is coated with a catalyst to promote NOx conversion. In one or more embodiments, the soot filter is coated with a catalyst to have at least one of the following functions: CO oxidation, hydrocarbon storage, hydrocarbon oxidation, NOx storage, NO oxidation, and fuel light off.

[0063] Ammonia slip from ammonia-SCR catalysts presents numerous problems. The odor threshold for NH3 is 20 ppm in air. Eye and throat irritation becomes significant above 100 ppm, and skin irritation occurs above 400 ppm. IDLH is 500 ppm in air. NH3 is caustic, especially in its aqueous solution form. When NH3 and water condense in the low-temperature region of the exhaust line downstream of the exhaust catalyst, a corrosive mixture is formed. Therefore, it is desirable to remove ammonia before it escapes from the tailpipe.

[0064] For this purpose, selective ammonia oxidation catalysts (AMOx) are used to convert excess ammonia into N2. It is desirable to provide a selective ammonia oxidation catalyst that can convert ammonia over a wide temperature range where ammonia slip occurs during an automobile's driving cycle, and that produces few nitrogen oxide byproducts. The AMOx catalyst should also minimize the generation of N2O, a powerful greenhouse gas. Ammonia oxidation catalysts or AMOx refer to catalysts that promote the oxidation of NH3. Preferably, ammonia oxidation catalysts (AMOx) are used to convert ammonia into N2, the main product, while minimizing nitrogen oxide byproducts.

[0065] In some embodiments, the SCR catalyst can optionally be integrated with other functions such as DOC, CSF, AMOx, CO oxidation, hydrocarbon storage, hydrocarbon oxidation, NOx storage, and NO oxidation, either as a single catalyst or in a single "brick".

[0066] In some embodiments, the SCR catalyst can optionally be integrated with other functions as a single catalyst or in a single "brick" through different layouts (zoning, stacking, homogeneity, etc.).

[0067] As used herein, the term "brick" refers to a single article, such as a monolith, e.g., a flow-through monolith, or a filter, e.g., a wall-flow filter.

[0068] Embodiment The present invention is further described by the following embodiments, which illustrate particularly advantageous embodiments. These embodiments are provided for illustrative purposes only and are not intended to limit the present invention.

[0069] 1. An SCR catalyst for reducing nitrogen oxides, comprising a carrier and an active substance on the carrier, The support, calculated as its oxide, is present in the SCR catalyst in an amount of 40 to 99% by mass relative to the total mass of the SCR catalyst. The active substance comprises vanadium and antimony, wherein vanadium is present in the SCR catalyst in an amount of 1 to 15% by mass relative to the total mass of the SCR catalyst, calculated as V2O5, and antimony is present in the SCR catalyst in an amount of 0.5 to 20% by mass relative to the total mass of the SCR catalyst, calculated as Sb2O3. The aforementioned SCR catalyst lasts for 60,000 hours. -1 An SCR catalyst having a space velocity and a molar ratio of 1:1 ammonia to NOx, hydrothermally aged at 550°C for 100 hours using 10% water, and exhibiting a denitrification efficiency of at least 60% at 200-300°C.

[0070] 2. The SCR catalyst according to Embodiment 1, wherein the support comprises a metal oxide of Ti, Si, W, Al, Ce, Zr, Mg, Ca, Ba, Y, La, Pr, Nb, Mo, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sn, Bi, or any mixture of two or more of the above metal oxides, or a molecular sieve.

[0071] 3. The SCR catalyst according to Embodiment 2, wherein the support comprises TiO2 and / or SiO2.

[0072] 4. The SCR catalyst according to Embodiment 3, wherein the support comprises TiO2 and SiO2, and SiO2 is present in an amount of 1 to 20% by mass, preferably 2.5 to 15% by mass, and more preferably 3 to 10% by mass, relative to the total mass of the support.

[0073] 5. The SCR catalyst according to any one of Embodiments 1 to 4, wherein the support is present in the SCR catalyst in an amount of 50 to 90% by mass relative to the total mass of the SCR catalyst, calculated as its oxide.

[0074] 6. The SCR catalyst according to Embodiment 5, wherein the support is present in the SCR catalyst in an amount of 60 to 85% by mass relative to the total mass of the SCR catalyst, calculated as a metal oxide or molecular sieve.

[0075] 7. The SCR catalyst according to any one of Embodiments 1 to 6, wherein vanadium is present in the SCR catalyst in an amount of 4 to 12% by mass relative to the total mass of the SCR catalyst, calculated as V2O5.

[0076] 8. The SCR catalyst according to Embodiment 7, wherein vanadium is present in the SCR catalyst in an amount of 5 to 10% by mass relative to the total mass of the SCR catalyst, calculated as V2O5.

[0077] 9. The SCR catalyst according to any one of Embodiments 1 to 8, wherein antimony is present in the SCR catalyst in an amount of 3 to 16% by mass relative to the total mass of the SCR catalyst, calculated as Sb2O3.

[0078] 10. The SCR catalyst according to Embodiment 9, wherein antimony is present in the SCR catalyst in an amount of 4 to 14% by mass relative to the total mass of the SCR catalyst, calculated as Sb2O3.

[0079] 11. The SCR catalyst according to any one of Embodiments 1 to 10, wherein the active substance has a V / Sb molar ratio in the range of 8:1 to 1:8, preferably 4:1 to 1:4, more preferably 2:1 to 1:2, calculated as each element.

[0080] 12. The following steps: 1) A step of adding an antimony precursor to DI water and stirring at a temperature in the range of 50 to 150 °C to obtain an antimony suspension; 2) A step of adding a vanadium precursor to the antimony suspension obtained in Step 1) and stirring at a temperature in the range of 50 to 150 °C to obtain an active substance suspension; 3) A step of drying the active substance suspension at a temperature in the range of 80 to 300 °C to obtain an active substance containing vanadium and antimony; 4) A step of mixing the active substance with a carrier in a solvent A method for preparing an SCR catalyst according to any one of Embodiments 1 to 11, comprising the above steps.

[0081] 13. An SCR catalyst article comprising the SCR catalyst according to any one of Embodiments 1 to 11, wherein the SCR catalyst is applied on a substrate having a monolithic structure.

[0082] 14. The SCR catalyst article according to Embodiment 13, wherein the loading amount of the SCR catalyst on the substrate is in the range of 0.5 to 10 g / in 3 Preferably 1 to 7 g / in 3 More preferably 2 to 5.5 g / in 3 of the range.

[0083] 15. An SCR catalyst article comprising the SCR catalyst according to any one of Embodiments 1 to 11, wherein the SCR catalyst further comprises a matrix material, and the SCR catalyst is formed into a honeycomb body by extrusion molding.

[0084] 16. (1) Using the SCR catalyst according to any one of Embodiments 1 to 11, (2) Exhaust gas from the engine is flowed through the SCR catalyst, (3) The above is carried out in the presence of a reducing agent. Methods for treating exhaust gases from internal combustion engines.

[0085] 17. A method for testing the NOx conversion rate, comprising contacting exhaust gas containing NOx with a reducing agent in the presence of an SCR catalyst according to any one of Embodiments 1 to 11, wherein at least a portion of the NOx is selectively reduced to N2 and H2O.

[0086] 18. An exhaust treatment system for an internal combustion engine, comprising a reducing agent injector and an SCR catalyst according to any one of embodiments 1 to 11.

[0087] 19. An exhaust treatment system for an internal combustion engine according to Embodiment 18, further comprising at least one catalyst selected from a diesel oxidation catalyst (DOC), a catalytic soot filter (CSF), and an ammonia oxidation catalyst (AMOx). [Examples]

[0088] The present invention is further illustrated by the following embodiments, which illustrate particularly advantageous embodiments. These embodiments are provided for illustrative purposes only and are not intended to limit the present invention.

[0089] Example 1 177.14 g of Sb2O3 was added to 800 g of DI water and stirred at 120°C for 2 hours to obtain an antimony suspension. Then, 110.51 g of V2O5 was added and stirred for a further 12 hours to obtain an active substance suspension. This active substance suspension was dried at 250°C to obtain active substance 1 containing vanadium and antimony. 6.8 g of active substance 1 and 88.5 g of SiO2 / TiO2 support (5% SiO2) were mixed and a slurry was formed with DI water and stirred for 30 minutes. A 30% aqueous ammonia solution was added dropwise to this suspension to obtain a pH of 7.0, and then 11.5 g of colloidal aqueous SiO2 solution (40% solid SiO2) was added. After stirring for 1 hour, a homogeneous slurry was obtained. Next, a 300 cpsi flow-through honeycomb cordierite substrate with a wall thickness of 5 mil was immersed in the obtained slurry to allow sufficient slurry to be supported. The material was hot-air dried at 150°C for 15 minutes, and then calcined in air at 550°C for 1 hour. After cooling to room temperature, the SCR catalyst article was further treated in 10% water vapor / air at 550°C for 100 hours. After cooling to room temperature, SCR catalyst article 1 was obtained containing 2.5% V2O5 SCR catalyst. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0090] Example 2 The synthesis procedure for SCR catalyst article 2 was the same as that for SCR catalyst article 1, except that the amounts of SiO2 / TiO2 powder and active substance 1 were adjusted to 79.5 g and 10.8 g, respectively. After cooling to room temperature, SCR catalyst article 2 was obtained having an SCR catalyst containing 4.0% V2O5. The total load of the wash coat on the substrate was 4.5 g / in. 3 That was the case.

[0091] Example 3 The synthesis procedure for SCR catalyst article 3 was the same as that for SCR catalyst article in Example 1, except that the amounts of SiO2 / TiO2 powder and active substance 1 were adjusted to 76.8 g and 13.5 g, respectively. After cooling to room temperature, SCR catalyst article 3 containing 5.0% V2O5 was obtained. The total load of the wash coat on the substrate was 4.5 g / in. 3 That was the case.

[0092] Example 4 The synthesis procedure for SCR catalyst article 4 was the same as that for SCR catalyst article in Example 1, except that the amounts of SiO2 / TiO2 powder and active substance 1 were adjusted to 74.1 g and 16.2 g, respectively. After cooling to room temperature, SCR catalyst article 4 containing 6.0% V2O5 was obtained. The total load of the wash coat on the substrate was 4.5 g / in. 3 That was the case.

[0093] Example 5 The synthesis procedure for SCR catalyst article 5 was the same as that for SCR catalyst article in Example 1, except that the amounts of SiO2 / TiO2 powder and active substance 1 were adjusted to 76.4 g and 19.0 g, respectively. Further treatment at 550°C for 100 hours in 10% water vapor / air was omitted. After cooling to room temperature, SCR catalyst article 5 was obtained having an SCR catalyst containing 7.0% V2O5. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0094] Example 6 SCR catalyst article 5 was further treated in 10% water vapor / air at 550°C for 100 hours. After cooling to room temperature, SCR catalyst article 6 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0095] Example 7 SCR catalyst article 5 was further treated in air at 600°C for 50 hours. After cooling to room temperature, SCR catalyst article 7 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0096] Example 8 The synthesis procedure for SCR catalyst article 8 was the same as that for the SCR catalyst article in Example 5, except that the amounts of SiO2 / TiO2 powder and active substance 1 were adjusted to 63.3 g and 27.0 g, respectively. After cooling to room temperature, SCR catalyst article 8 containing 10.0% V2O5 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0097] Example 9 SCR catalyst article 8 was further treated in 10% water vapor / air at 550°C for 100 hours. After cooling to room temperature, SCR catalyst article 9 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0098] Example 10 (Comparative Example 1) 86.8 g of SiO2 / TiO2 support, 23.8 g of vanadyl oxalate solution with a 10.5% V2O5 content, and 3.8 g of Sb2O3 were mixed in 100 g of DI water at room temperature. After stirring the suspension for 30 minutes, a 30% aqueous ammonia solution was added to raise the pH of the suspension system to 6.0-7.0. Then, 23.2 g of SiO2 sol with a 30% SiO2 content was added last. After stirring for 1 hour, a homogeneous slurry was obtained. Next, a 300 cpsi flow-through honeycomb cordierite substrate with a wall thickness of 5 mil was immersed in the obtained slurry to allow sufficient slurry to be supported. It was hot-air dried at 150°C for 15 minutes, and then calcined in air at 550°C for 1 hour. After cooling to room temperature, the SCR catalyst article was further treated in 10% water vapor / air at 550°C for 100 hours. After cooling to room temperature, a comparative SCR catalyst article containing 2.5% V2O5 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0099] Example 11 (Comparative Example 2) The synthesis procedure for comparative SCR catalyst article 2 was the same as that for comparative example 1, except that the amounts of SiO2 / TiO2 powder, vanadyl oxalate solution, and Sb2O3 were adjusted to 83.1 g, 38.1 g, and 6.0 g, respectively. After cooling to room temperature, comparative SCR catalyst article 2 was obtained, containing an SCR catalyst with 4.0% V2O5. The total load of the wash coat on the substrate was 4.5 g / in. 3 That was the case.

[0100] Example 12 (Comparative Example 3) The synthesis procedure for comparative SCR catalyst article 3 was the same as that for comparative example 1, except that the amounts of SiO2 / TiO2 powder, vanadyl oxalate solution, and Sb2O3 were adjusted to 80.5 g, 47.6 g, and 7.5 g, respectively. After cooling to room temperature, comparative SCR catalyst article 3 was obtained, containing an SCR catalyst with 5.0% V2O5. The total load of the wash coat on the substrate was 4.5 g / in. 3 That was the case.

[0101] Example 13 (Comparative Example 4) The synthesis procedure for comparative SCR catalyst article 4 was the same as that for comparative example 1, except that the amounts of SiO2 / TiO2 powder, vanadyl oxalate solution, and Sb2O3 were adjusted to 78.1 g, 57.1 g, and 9.0 g, respectively. After cooling to room temperature, comparative SCR catalyst article 4 was obtained, containing 6.0% V2O5 as an SCR catalyst. The total load of the wash coat on the substrate was 4.5 g / in. 3 That was the case.

[0102] Example 14 (Comparative Example 5) The synthesis procedure for comparative SCR catalyst article 5 was the same as that for comparative example 1, except that the amounts of SiO2 / TiO2 powder, vanadyl oxalate solution, and Sb2O3 were adjusted to 75.5 g, 66.7 g, and 10.5 g, respectively. Further treatment at 550°C for 100 hours in 10% water vapor / air was omitted. After cooling to room temperature, comparative SCR catalyst article 5 containing 7.0% V2O5 was obtained. The total load of the wash coat on the substrate was 3.0 g / in.3 That was the case.

[0103] Example 15 (Comparative Example 6) Comparative SCR catalyst article 5 was further treated in 10% water vapor / air at 550°C for 100 hours. After cooling to room temperature, comparative SCR catalyst article 6 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0104] Example 16 (Comparative Example 7) Comparative SCR catalyst article 5 was further treated in air at 600°C for 50 hours. After cooling to room temperature, comparative SCR catalyst article 7 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0105] Example 17 (Comparative Example 8) The synthesis procedure for comparative SCR catalyst article 8 was the same as that for the SCR catalyst article of Comparative Example 5, except that the amounts of SiO2 / TiO2 powder, vanadyl oxalate solution, and Sb2O3 were adjusted to 68.1 g, 95.2 g, and 15.5 g, respectively. After cooling to room temperature, comparative SCR catalyst article 8 containing 10.0% V2O5 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0106] Example 18 (Comparative Example 9) Comparative SCR catalyst article 8 was further treated in 10% water vapor / air at 550°C for 100 hours. After cooling to room temperature, comparative SCR catalyst article 9 was obtained. The total load of the wash coat on the substrate was 3.0 g / in. 3 That was the case.

[0107] SCR performance testing of SCR catalyst articles from Examples 1-9 and Comparative Examples 1-9 Samples measuring 1 inch in diameter and 4 inches in length were cut from the core of each SCR catalyst article prepared in Examples 1-9 and Comparative Examples 1-9. Each sample was placed in a fixed-bed simulator in the laboratory. The supply gas consisted of 10 vol% H2O, 5 vol% O2, 500 ppm NO, 500 ppm NH3, and the remainder N2, in volume ratios, for 60,000 h -1 The fluid was supplied at the given spatial velocity. The results of the SCR performance test are summarized in Table 1 below.

[0108] SCR performance was characterized by the NOx conversion rate calculated according to the following equation.

[0109] NOx conversion rate = (NOx 入口 -NOx 出口 ) / NOx 入口 ×100%

[0110] [Table 1]

[0111] As can be seen from the results shown in Table 1, the catalysts of Examples 2 to 9, which contain 4% or more V2O5, achieved a significantly higher NOx conversion rate at 200°C compared to the catalysts of Comparative Examples 2 to 9.

Claims

1. An SCR catalyst for reducing nitrogen oxides, comprising a carrier and an active substance on the carrier, The support is calculated as a metal oxide or molecular sieve and is present in the SCR catalyst in an amount of 60 to 85% by mass relative to the total mass of the SCR catalyst. The active substance comprises vanadium and antimony, and vanadium is V ２ O ５ Calculated as follows, the antimony is present in the SCR catalyst in an amount of 7 to 12% by mass relative to the total mass of the SCR catalyst, and Sb ２ O ３ Calculated as follows, the amount present in the SCR catalyst is 8 to 16% by mass relative to the total mass of the SCR catalyst. The aforementioned SCR catalyst lasts for 60,000 hours. －１ An SCR catalyst having a space velocity and a molar ratio of 1:1 ammonia to NOx, hydrothermally aged at 550°C for 100 hours using 10% water, and exhibiting a denitrification efficiency of at least 60% at 200-300°C.

2. The SCR catalyst according to claim 1, wherein the carrier comprises a metal oxide of Ti, Si, W, Al, Ce, Zr, Mg, Ca, Ba, Y, La, Pr, Nb, Mo, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sn, Bi, or any mixture of two or more of the metal oxides, or a molecular sieve.

3. The carrier is TiO ２ and / or SiO ２ The SCR catalyst according to claim 2, comprising:

4. The carrier is TiO ２ and SiO ２ and contains SiO ２ is present in an amount of 1 to 20% by mass, preferably 2.5 to 15% by mass, more preferably 3 to 10% by mass based on the total mass of the carrier, and the SCR catalyst according to claim 3.

5. The following steps: 1) Adding an antimony precursor to DI water and stirring at a temperature in the range of 50 to 150°C to obtain an antimony suspension; 2) Adding a vanadium precursor to the antimony suspension obtained in step 1), stirring at a temperature in the range of 50 to 150°C to obtain an active substance suspension, 3) A step of drying the suspension of the active substance at a temperature in the range of 80 to 300°C to obtain an active substance containing vanadium and antimony, 4) A step of mixing the active substance with the support in a solvent. A method for preparing an SCR catalyst according to any one of claims 1 to 4, comprising:

6. An SCR catalyst article comprising the SCR catalyst described in any one of claims 1 to 4, wherein the SCR catalyst is applied on a substrate having a monolithic structure.

7. The amount of the SCR catalyst supported on the substrate is 0.5 to 10 g / in. ３ Preferably 1 to 7 g / in ３ More preferably 2 to 5.5 g / in ３ The SCR catalyst article according to claim 6, which is within the range of [specify range].

8. An SCR catalyst article comprising the SCR catalyst according to any one of claims 1 to 4, wherein the SCR catalyst further comprises a matrix material, and the SCR catalyst is formed into a honeycomb structure by extrusion molding.

9. (1) Using the SCR catalyst described in any one of claims 1 to 4, (2) Exhaust gas from the engine is passed through the SCR catalyst, (3) The above is carried out in the presence of a reducing agent. Methods for treating exhaust gases from internal combustion engines.

10. A method for testing the NOx conversion rate, comprising contacting exhaust gas containing NOx with a reducing agent in the presence of an SCR catalyst according to any one of claims 1 to 4, wherein at least a portion of the NOx is N ２ and H ２ A method for selectively reducing to O.

11. An exhaust treatment system for an internal combustion engine, comprising a reducing agent injector and an SCR catalyst according to any one of claims 1 to 4.

12. The exhaust treatment system for an internal combustion engine according to claim 11, further comprising at least one catalyst selected from a diesel oxidation catalyst (DOC), a catalytic soot filter (CSF), and an ammonia oxidation catalyst (AMOX).

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