Selective catalytic reduction (SCR) catalysts comprising complex oxides containing V and Sb, methods for their preparation and their use for the removal of nitrogen oxides

Abstract

The present invention relates to a process for the preparation of a catalyst composition comprising - a support comprising TiO2, - a composite oxide comprising vanadium and antimony, having a rutile structure different from VSbO4 and V 0.92 Sb 0.92 O4 as determined by X-ray diffraction (XRD) analysis using Cu Ka radiation and - optionally, one or more selected from silicon oxide, vanadium oxide and antimony oxide; said process comprising the steps of: (i) mixing vanadium / antimony oxide and optional silicon source with the support comprising TiO2 in a solvent to obtain a suspension; (ii) optionally, applying the suspension onto a substrate; (iii) drying at a temperature in the range of 80 to 250 °C; (iv) calcination at a temperature of 600 °C to 700 °C.

Description

[0001] This application is a divisional application of the invention patent application with application number 201680081959.X, the original application being filed on July 26, 2016, entitled "Selective Catalytic Reduction (SCR) Catalyst Containing Composite Oxides Containing V and Sb, Preparation Method Thereof and Use Thereof for Removal of Nitrogen Oxides". Technical Field

[0002] This invention generally relates to catalysts for the removal of nitrogen oxides (NOx). More specifically, this invention relates to selective catalytic reduction (SCR) catalysts containing vanadium and antimony on a support, methods for their preparation, and their use for NOx removal. Background Technology

[0003] NOx emitted as exhaust gases from mobile pollution sources such as vehicles and stationary pollution sources such as power plants is harmful to the environment and human health. To remove NOx from exhaust gases, catalytic reduction (SCR) methods have been developed to date. SCR is suitable for treating large volumes of exhaust gas, and methods involving the addition of ammonia as a reducing agent to selectively catalytically reduce NOx to N2 have been reported as particularly effective. Catalysts used for such selective catalytic reduction (SCR) need to reduce NOx over a wide temperature range, especially at the lowest possible temperature below 300°C.

[0004] For example, SCR catalysts in the form of supported vanadium (V) / antimony (Sb) binary systems, such as V / Sb / TiO2, have been disclosed in KR 101065242 B1, US 2009 / 143225 A1, and US 4221768. It is believed that incorporating Sb as a co-catalyst into conventional V-containing catalysts can lead to improved SCR performance.

[0005] US 8975206 B2 discloses catalyst compositions comprising vanadates represented by XVO4 / S, wherein XVO4 represents Bi-, Sb-, Ga-, and / or Al-vanadates and S is a TiO2-containing support. VSbO4 supported on TiO2 / WO3 / SiO2 is specifically given as an example, prepared by mixing V and Sb source solutions, drying at 120°C, and calcining at 550°C for 20 hours to obtain VSbO4, which is then supported on TiO2 / WO3 / SiO2. XRD patterns of the structures of vanadates, particularly VSbO4, are not disclosed in this patent.

[0006] WO 2013 / 179129 A2 discloses an SCR filter comprising a substrate in the form of a wall-flow filter and a catalyst supported on the substrate, the catalyst comprising a support and a vanadate component. The vanadate has a composition of formula (A) x (T) y(R) z The patent application defines the structure of FeVO4, where "A" is an alkaline earth metal, "T" is a transition metal, "R" is a rare earth metal, and "x", "y", and "z" are the molar ratios of the respective metals to vanadium, where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and x + y + z = 1. This patent application only discloses FeVO4 as the vanadate component. The application does not discuss the SCR performance of a wall-flow filter containing FeVO4 supported on a substrate.

[0007] Despite the existence of known SCR catalysts, there is still a need for SCR catalysts that exhibit excellent NOx removal activity, especially in applications involving both mobile and stationary exhaust emissions. Summary of the Invention

[0008] One object of the present invention is to provide a novel SCR catalyst with improved NOx removal, particularly for applications involving both mobile and stationary exhaust emissions. This object is achieved by: a catalyst composition, a method for preparing the same, and the use of the catalyst composition for the selective catalytic reduction of nitrogen oxides. The present invention particularly relates to the following aspects.

[0009] 1. Use of a catalyst composition for the selective catalytic reduction of nitrogen oxides, said catalyst composition comprising: - TiO2-containing support, - A composite oxide containing vanadium and antimony, which exhibits properties different from VSbO4 and V 0.92 Sb 0.92 The rutile structure of O4 was determined by X-ray diffraction (XRD) analysis using Cu Kα radiation, and - Optionally, one or more of silicon oxide, vanadium oxide and antimony oxide are selected.

[0010] 2. According to the application of aspect 1 above, the vanadium and antimony-containing composite oxide is characterized by XRD diffraction peaks on the (110) or (101) planes that are higher than those on VSbO4 and V. 0.92 Sb 0.92 O4 level is at least 0.1 o At 2θ.

[0011] 3. According to the application of aspect 2 above, the vanadium and antimony-containing composite oxide is characterized by XRD diffraction peaks on the (101) plane that are higher than those on VSbO4 and V. 0.92 Sb 0.92 O4 level is at least 0.2 ppm higher. o Preferably at least 0.3 o More preferably at least 0.5 o At 2θ.

[0012] 4. According to the use of any one of aspects 1 to 3 above, the vanadium- and antimony-containing composite oxide is characterized in that the XRD diffraction peak of the (110) plane is at 27.25. o Up to 29.00 o The XRD diffraction peak at 2θ within the range and on the (101) plane is at 35.43. o Up to 37.00 o At point 2θ within the range.

[0013] 5. The use according to any one of aspects 1 to 4 above, wherein vanadium is present in the catalyst composition at 0.5 to 6 wt%, preferably 1 to 4.5 wt%, more preferably 2 to 4 wt%, calculated by element V, wherein the vanadium comprises vanadium in a vanadium- and antimony-containing composite oxide and optionally vanadium oxide; and wherein antimony is present in the catalyst composition at 0.8 to 16 wt%, preferably 3.5 to 14 wt%, more preferably 5 to 10 wt%, calculated by element Sb, wherein the antimony comprises antimony in a vanadium- and antimony-containing composite oxide and optionally antimony oxide.

[0014] 6. The use according to any one of aspects 1 to 5 above, wherein the catalyst composition is in a molded form, preferably in an extruded form or supported on a substrate.

[0015] 7. According to the use of aspect 1 above, the nitrogen oxides are present in exhaust gas from an internal combustion engine such as a diesel engine, a power plant or an incinerator.

[0016] 8. A method for preparing a catalyst composition as described in any one of aspects 1 to 6 above, comprising the steps of: (i) A suspension is obtained by mixing vanadium / antimony oxide and an optional silicon source with a TiO2-containing support in a solvent; (ii) Optionally, the suspension is applied to a substrate; (iii) Dry at a temperature ranging from 80 to 250°C; (iv) Calcination at a temperature of at least 500°C.

[0017] 9. The method according to aspect 8 above, wherein the calcination in step (iv) is carried out at a temperature in the range of 500°C to 700°C, more preferably 550°C to 700°C, even more preferably 600°C to 700°C, and most preferably 650°C to 700°C.

[0018] 10. According to the method of aspect 8 or 9 above, wherein the vanadium / antimony oxide used in step (i) is prepared as follows: (a) Provide a suspension containing vanadium oxide and antimony oxide; and (b) The suspension is dried at a temperature of 80°C to 250°C to obtain vanadium / antimony oxide.

[0019] 11. According to the method of aspect 8 or 9 above, wherein the vanadium / antimony oxide used in step (i) is prepared as follows: (a') Provide a suspension or solution containing a vanadium source and an antimony source; (b') Precipitate and separate the vanadium / antimony oxide from the suspension or solution; and (c') Optionally, dry at a temperature of 80°C to 250°C.

[0020] 12. The method according to any one of aspects 8 to 11 above, which excludes step (ii) and optionally includes a molding step to obtain a shaped catalyst composition.

[0021] 13. A catalyst composition obtained / obtainable by any one of the methods described in aspects 8 to 12 above.

[0022] 14. Use of the catalyst composition according to aspect 13 above for the selective catalytic reduction of nitrogen oxides.

[0023] 15. According to the use of aspect 14 above, wherein the nitrogen oxides are present in exhaust gas from an internal combustion engine such as a diesel engine, a power plant or an incinerator. Brief description of the attached diagram

[0024] Figure 1 The XRD pattern of the catalyst composition prepared in Example 1 according to the present invention is shown.

[0025] Figure 2 The XRD pattern of the catalyst composition prepared in Example 2 according to the present invention is shown.

[0026] Figure 3 The XRD pattern of the catalyst composition prepared in Example 3 according to the present invention is shown.

[0027] Figure 4 STEM-EDS diagram of the catalyst composition prepared in Example 2 according to the present invention. Detailed Implementation

[0028] <Catalyst Composition>

[0029] This invention provides a catalyst composition comprising: - TiO2-containing support, - A composite oxide containing vanadium and antimony, which exhibits properties different from VSbO4 and V 0.92 Sb 0.92 The rutile structure of O4 was determined by X-ray diffraction (XRD) analysis using Cu Kα radiation, and - Optionally, one or more of silicon oxide, vanadium oxide and antimony oxide are selected.

[0030] The support that can be used in the catalyst composition according to the invention can be any support containing TiO2. Preferably, the support is composed of TiO2, TiO2 and SiO2, TiO2 and WO3, TiO2 and SiO2 and WO3, TiO2 and Al2O3, or TiO2 and ZrO2. More preferably, the support is composed of TiO2.

[0031] The TiO2 to be used in this invention is commercially available or can be prepared by conventional methods known in the art. In a further embodiment of the invention, the TiO2 to be used is in the anatase form.

[0032] In one embodiment, the vanadium- and antimony-containing composite oxide exhibits superior performance compared to rutile VSbO4 and V. 0.92 Sb 0.92 O4 level is at least 0.1 o Preferably at least 0.2 o The XRD diffraction peaks at the 2θ value of the (110) or (101) plane were determined by XRD analysis using Cu Kα radiation.

[0033] In this invention, VSbO4 and V 0.92 Sb 0.92 Any 2θ value of O4 refers to: those for VSbO4 according to PDF 00-016-0600, and those for the reference V. 0.92 Sb 0.92 For O4, according to those in PDF 04-007-9467, it is available from 2014 PDF4Database, International Center for Diffraction Data, Newtown Square, Pennsylvania, USA.

[0034] Unless otherwise stated, the XRD diffraction analysis used in this invention refers to XRD diffraction using Cu Kα radiation.

[0035] In a preferred embodiment, the vanadium- and antimony-containing composite oxide exhibits a higher performance than VSbO4 and V. 0.92 Sb 0.92 O4 level is at least 0.1 o Preferably at least 0.2 o More preferably at least 0.3 o Even more preferably, at least 0.5 o The optimal value is at least 0.7. o The XRD diffraction peak at 2θ on the (101) plane.

[0036] In a particularly preferred embodiment, the vanadium and antimony-containing composite oxide is characterized by an XRD diffraction peak at 27.25 on the (110) plane. o Up to 29.00 o The XRD diffraction peak at 2θ within the range and on the (101) plane is at 35.43. o Up to 37.00 o At point 2θ within the range.

[0037] Unbound by any theory, it is speculated that vanadium- and antimony-containing composite oxides can be derived from the empirical formula VSb. a Ti b O c This indicates that a is the molar ratio of Sb to V with a value greater than 0 and less than 1, b is the molar ratio of Ti to V with a value less than 1, and c is the molar ratio of O to V, depending on the valence requirements of the present elements. In one particular embodiment, titanium exists together with vanadium and antimony in a composite oxide having a rutile structure, i.e., b > 0. In a further embodiment, the formula VSb a Ti b O c The sum of the exponents a and b in the equation is ≤ 1.

[0038] In another specific embodiment, the vanadium and antimony-containing composite oxide does not contain silicon. In other words, silicon is not present in the rutile structure of the composite oxide.

[0039] The vanadium content in the catalyst composition according to the invention is preferably from 0.5 to 6 wt% (based on elemental V), preferably from 1 to 4.5 wt%, more preferably from 2 to 4 wt%, wherein the vanadium includes vanadium- and antimony-containing composite oxides and optionally vanadium oxides. The antimony content in the catalyst composition according to the invention is preferably from 0.8 to 16 wt% (based on elemental Sb), preferably from 3.5 to 14 wt%, more preferably from 5 to 10 wt%, wherein the antimony includes vanadium- and antimony-containing composite oxides and optionally antimony oxides.

[0040] The silicon content (if present) in the catalyst composition according to the invention is preferably in the range of 0.2 to 9.5% by weight, more preferably 0.4 to 7% by weight, and more preferably 0.9 to 4.6% by weight, calculated by elemental Si.

[0041] The titanium content, calculated as TiO2, including those present in the support and those possibly present in the vanadium and antimony composite oxide, is preferably in the range of 50 to 97.5% by weight, more preferably 61 to 93% by weight, and more preferably 73 to 90% by weight, based on the total weight of the catalyst composition according to the invention.

[0042] The catalyst composition according to the invention can be used in powder form or in molded form. For example, the catalyst composition according to the invention can be molded into beads, spheres, pellets, or pulverized particles, etc., according to various techniques known in the art. It should be understood that any conventional matrix material or auxiliary agent can be introduced as needed during the molding process and may thereby be included in the molded form of the catalyst composition according to the invention.

[0043] Alternatively, the catalyst composition according to the invention can be applied to a substrate. The substrate is not particularly limited and can be, for example, a honeycomb substrate or a wall-flow substrate. The substrate can be any material commonly used in the preparation of catalysts, such as ceramics or metals.

[0044] In a preferred embodiment, the present invention provides a catalyst composition supported on a substrate as a wash coating, wherein the catalyst composition comprises: - TiO2-containing support, - A composite oxide containing vanadium and antimony, which exhibits properties different from VSbO4 and V 0.92 Sb 0.92 The rutile structure of O4 was determined by X-ray diffraction (XRD) analysis using Cu Kα radiation, and - Optionally, one or more of silicon oxide, vanadium oxide and antimony oxide are selected.

[0045] In a preferred embodiment, the substrate comprises a ceramic or metal honeycomb structure. Any suitable substrate can be used, such as a monolithic substrate having fine, parallel gas flow channels extending through the substrate from its inlet or outlet surface. The channels, which are essentially straight paths from their fluid inlets to their fluid outlets, are defined by walls on which the catalyst composition is carried as a wash coat to allow the gas flowing through the channels to contact the catalyst composition. The flow channels of the monolithic substrate are thin-walled channels that can have any suitable cross-sectional shape and size, such as trapezoidal, rectangular, square, sinusoidal, hexagonal, elliptical, circular, etc.

[0046] Such a monolithic substrate can contain up to approximately 900 or more channels (i.e., “chambers”) per square inch of cross-section, although much smaller quantities can be used. For example, the substrate may have approximately 50 to 600, and more typically approximately 200 to 400 chambers per square inch (“cpsi”). The chambers may have rectangular, square, circular, elliptical, triangular, hexagonal, or other polygonal cross-sections.

[0047] Preferably, the catalyst composition can be in the form of 1-10 g / in 3 Preferred concentration: 1-7 g / in 3 More preferably 2-5.5 g / in 3 The amount is loaded onto the substrate.

[0048] As described below, the catalyst composition according to the invention can be used to reduce nitrogen oxides (NOx), particularly in exhaust gases from internal combustion engines or power plants.

[0049] It should be understood that, unless otherwise mentioned, the contents of the support and components are calculated in each case relative to the total weight of the catalyst composition according to the invention, excluding the substrate if present.

[0050] <Methods for preparing catalyst compositions>

[0051] In another aspect of the present invention, a method for preparing a catalyst composition according to the present invention is provided, comprising the steps of: (i) A suspension is obtained by mixing vanadium / antimony oxide and an optional silicon source with a TiO2-containing support in a solvent; (ii) Optionally, the suspension is applied to a substrate; (iii) Dry at a temperature ranging from 80 to 250°C; (iv) Calcination at a temperature of at least 500°C.

[0052] In this invention, vanadium / antimony oxide is intended to mean a mixture of vanadium oxide and antimony oxide, an oxide of vanadium and antimony, or a combination of an oxide of vanadium and antimony and a mixture of vanadium oxide and antimony oxide.

[0053] In the method according to the invention, when a silicon source is used, it is not particularly limited, but is preferably selected from silicic acid, silica sol, quartz, fused or amorphous silica, silicates such as sodium silicate, alkoxysilanes, silicone resins, etc., or any combination of two or more of them.

[0054] The above description of the support for the catalyst composition is applicable to the method according to the present invention.

[0055] In one embodiment of the method according to the invention, the vanadium / antimony oxide used in step (i) is prepared as follows: (a) Provide a suspension containing vanadium oxide and antimony oxide; and (b) The suspension is dried at a temperature ranging from 80°C to 250°C to obtain vanadium / antimony oxide.

[0056] In this embodiment, the vanadium oxide and antimony oxide used in step a) are not particularly limited, for example, V2O5 and Sb2O3 can be used.

[0057] In another embodiment of the method according to the invention, the vanadium / antimony oxide used in step (i) is prepared as follows: (a') Provide a suspension or solution containing a vanadium source and an antimony source; (b') Precipitate and separate the vanadium / antimony oxide from the suspension or solution; and (c') Optionally, dry at a temperature in the range of 80°C to 250°C.

[0058] In this invention, vanadium source and antimony source are intended to represent vanadium-containing compounds and antimony-containing compounds, respectively, which can be converted into vanadium / antimony oxides in this method.

[0059] In this embodiment, the vanadium source is preferably selected from ammonium vanadate, vanadium oxalate, vanadium pentoxide, vanadium monoethanolamine, vanadium chloride, vanadium trichloride, vanadium oxysulfate, vanadium antimonite, vanadium antimonate, and vanadium oxides. The antimony source is preferably selected from antimony acetate, antimony glycolate, antimony sulfate, antimony nitrate, antimony chloride, antimony trisulfide, antimony oxides, and antimony vanadate.

[0060] In the method according to the invention, the solvent used in step (i) and the solvent in the suspension or solution in steps (a) and (a') can be any suitable solvent known in the art, preferably an aqueous solvent, and preferably DI water.

[0061] In step (ii) of the method according to the invention, optionally, the suspension is applied to the substrate by any method known in the art. For example, the lower end of the substrate may be immersed in the suspension and a vacuum may be applied to the upper end of the substrate to draw the suspension into the substrate channels to the desired length. The above description of the substrate supporting the catalyst composition is applicable to the method according to the invention.

[0062] In step (iii) of the method according to the invention, the suspension from step (i) or the substrate obtained from step (ii) is dried at a temperature in the range of 80°C to 250°C, preferably 100°C to 200°C, and more preferably 100°C to 150°C. Drying can be carried out in any manner known in the art, without particular limitation.

[0063] The preferred temperature ranges discussed above also apply to steps (b) and (c') in the corresponding embodiments of the method according to the invention. Drying in these steps can also be carried out in any manner known in the art, without particular limitation, although spray drying is preferred.

[0064] In step (iv) of the method according to the invention, calcination is preferably carried out at a temperature in the range of 500°C to 700°C, more preferably above 500°C to 700°C, more preferably 550°C to 700°C, even more preferably 600°C to 700°C, and most preferably 650°C to 700°C.

[0065] According to one embodiment of the method of the present invention, if appropriate, the precipitation in step (b') is carried out in the presence of a precipitant such as ammonia, ammonium bicarbonate, ammonium carbonate, sodium hydroxide, potassium hydroxide, sodium carbonate, etc.

[0066] If necessary, any other conventional additives, such as dispersants, binders and / or thickeners, may be used in the process according to the method of the present invention.

[0067] In a further embodiment, the method according to the invention does not include applying the suspension from step (i) to a substrate, which optionally includes a molding step to obtain a shaped catalyst composition. If desired, molding is preferably performed before the calcination step (iv) and, preferably, before the drying step (iii). It should be understood that any conventional matrix material or auxiliaries can be incorporated during the molding process as needed.

[0068] <Methods for Selective Catalytic Reduction of Nitrogen Oxides (NOx) in Exhaust Gas>

[0069] In another aspect, the present invention relates to the use of catalyst compositions according to the invention or catalyst compositions obtained / available by the method according to the invention for the selective catalytic reduction of NOx, particularly NOx in exhaust gas.

[0070] Exhaust gas that can be treated with the catalyst composition according to the invention or with a catalyst composition obtained / available by the method according to the invention is any exhaust gas containing NOx to be removed or reduced. The exhaust gas originates from, for example, but not limited to, internal combustion engines, power plants, or incinerators.

[0071] Accordingly, a method for reducing NOx in exhaust gas from an internal combustion engine is provided, comprising contacting the exhaust gas with a catalyst composition according to the invention or a catalyst composition obtained / available by the method according to the invention.

[0072] In one particular embodiment, exhaust gas is contacted with the catalyst composition according to the invention or a catalyst composition obtained / available by the method according to the invention at a temperature ranging from 150°C to 650°C, 180°C to 600°C, or 200°C to 550°C.

[0073] Contact between the exhaust gas and the catalyst composition according to the invention or a catalyst composition obtained / available by the method according to the invention is carried out in the presence of a reducing agent. The reducing agent that can be used in the invention can be any reducing agent known in the art for reducing NOx, such as NH3. NH3 may be derived from urea.

[0074] Other catalysts may be present upstream or downstream of the exhaust flow direction.

[0075] In a preferred embodiment of the invention, the internal combustion engine is a diesel engine.

[0076] The invention is further illustrated by the following examples, which illustrate particularly advantageous embodiments. Although these examples are for illustrative purposes, they are not intended to limit the invention.

[0077] Example

[0078] Preparation of vanadium / antimony oxides—Compound 1

[0079] 40.0 g of V₂O₅ and 64.1 g of Sb₂O₃ were mixed in 300 g of DI water and stirred to form a suspension. The suspension was spray-dried at 200 °C to form an oxide mixture with a V:Sb molar ratio of 1:1.

[0080] Example 1

[0081] 10.4 g of Compound 1 was added to 100.0 g of DI water and stirred for 30 minutes. Then, 84.6 g of TiO2 powder and 16.7 g of colloidal SiO2 aqueous solution (30% SiO2 solids) were added. The resulting suspension was applied to a 400 / 6 honeycomb cordierite substrate (400 refers to the number of chambers per square inch (cpsi) and 6 refers to the wall thickness between channels in millimeters), dried overnight at 120°C, and then calcined in air at 500°C for 3 hours. After cooling to room temperature, catalyst 1 was obtained. The total loading of the wash coating on the substrate was 3.0 g / in. 3 .

[0082] Example 2

[0083] Example 1 was repeated, except that calcination was carried out at 650°C for 3 hours to obtain catalyst 2.

[0084] Example 3

[0085] Example 1 was repeated, except that the calcination was carried out at 700°C for 3 hours to obtain catalyst 3.

[0086] Example 4

[0087] 13.0 g of Compound 1 was added to 100.0 g of DI water and stirred for 30 minutes. Then, 82.0 g of TiO2 powder and 16.7 g of colloidal SiO2 aqueous solution (30% SiO2 solids) were added. The resulting suspension was applied to a 400 / 6 honeycomb cordierite substrate and dried overnight at 120°C, followed by calcination in air at 500°C for 3 hours. After cooling to room temperature, catalyst 4 was obtained. The total loading of the coating on the substrate was 3.0 g / in. 3 .

[0088] Example 5

[0089] Example 4 was repeated, except that the calcination was carried out at 650°C for 3 hours to obtain catalyst 5.

[0090] Example 6

[0091] Example 4 was repeated, except that the calcination was carried out at 700°C for 3 hours to obtain catalyst 6.

[0092] The washed-out coatings of catalysts 1 to 3 obtained in the above embodiments were characterized by XRD analysis using Cu Kα radiation with a step size of 0.02. o D8 Advance Series II, Bruker AXS GmbH. XRD patterns of catalysts 1, 2, and 3 are shown in [the diagram / image / data]. Figure 1 , 2 In section 3, XRD data of the rutile structure are compared with the cell parameters of the washed coatings of catalysts 1 to 3, and V... 0.92 Sb 0.92 The O4 and VSbO4 groups are summarized in Table 1.

[0093] Table 1. VSbO4 and V 0.92 Sb 0.92 XRD data of O4 and the wash coatings of catalysts 1 to 3 2014 PDF4 Database, International Center for Diffraction Data,Newtown Square, Pennsylvania, USA The 2θ values ​​of the TiO2 anatase (101) facet of catalysts 1 to 3 are the same and consistent with the known 2θ values ​​of the TiO2 anatase (101) facet. The XRD patterns and data of the rutile-type structures associated with catalysts 1 to 3 are believed to be reliable.

[0094] from Figures 1 to 3 As can be seen from the XRD pattern shown and the data given in Table 1, the washed coating of catalyst 1 exhibits the same characteristics as the reference V. 0.92 Sb 0.92 O4 exhibits similar XRD diffraction (2θ value) and cell parameters (a, c values). The diffraction peaks of the (101) plane of the washed coatings of catalysts 2 and 3 are similar to those of reference VSbO4 and reference V. 0.92 Sb 0.92 O4 shifts at least 0.5 towards a higher 2θ value. oFurthermore, the rutile-related parameter c values ​​of catalysts 2 and 3 are significantly lower than those of reference VSbO4 and reference V. 0.92 Sb 0.92 O4. This indicates that catalysts 2 and 3 contain substances different from V. 0.92 Sb 0.92 TiO2 anatase structure and complex oxide rutile structure of O4 and VSbO4.

[0095] Catalyst 2 was also analyzed by scanning transmission electron microscopy-energy dispersive spectroscopy (STEM-EDS) using Oxford Instruments' X-Max. N 80 mm 2 An EDS detector was used in conjunction with a FEI Magellan 400 scanning electron microscope from the FEI Company. The sample was ultrasonically dispersed in ethanol, dropped onto a copper grid covered with a carbon film, and then subjected to STEM microstructure analysis at 30 kV. Figure 4 The STEM-EDS images shown depict V and Sb distributed almost identically on TiO2, while the distribution of SiO2 is different or independent. This indicates that Si is not incorporated into the rutile structure.

[0096] SCR activity tests of catalysts 1 to 6

[0097] The SCR activity of catalysts 1 through 6 for NOx removal was tested. All catalysts were placed in a fixed-bed laboratory simulator for testing. 7 grams of cylindrical catalyst with a diameter of 1 inch and a length of 3 inches were used in each test. The feed gas consisted of 500 ppm NH3, 500 ppm NO, 5% H2O, 10% O2, and the balance N2. The space velocity was 60,000 h⁻¹. -1 The results of the activity tests are summarized in Table 2.

[0098] Table 2. SCR activity of catalysts

[0099] Catalysts 1 to 3 were prepared from the same raw material formulation, differing only in the calcination temperature during preparation. It can be seen that catalysts 2 and 3, obtained at higher calcination temperatures (650℃ and 700℃, respectively), exhibited significantly higher NOx conversion rates than catalyst 1. It is speculated that catalysts obtained at calcination temperatures above 500℃ contain substances different from V, as characterized by XRD analysis. 0.92 Sb 0.92 Composite oxides of O4 and VSbO4 with rutile structures. A comparison of catalysts 4 vs. 5 and 6 also shows the positive effect of composite oxides obtained at higher calcination temperatures on the SCR activity of the catalysts.

[0100] Comparative Example

[0101] For comparison, more catalyst compositions were prepared.

[0102] Comparative Example 1

[0103] 10.4 g of Compound 1, pretreated at 550 °C for 20 h, was added to 100.0 g of DI water and stirred for 30 min. Then, 84.6 g of TiO2 powder and 16.7 g of colloidal SiO2 aqueous solution (30% SiO2 solids) were added. The resulting suspension was applied to a 400 / 6 honeycomb cordierite substrate and dried overnight at 120 °C, followed by calcination in air at 650 °C for 3 h. After cooling to room temperature, comparative catalyst 1 was obtained. The total loading of the wash coating on the substrate was 3.0 g / in. 3 .

[0104] Comparative Example 2

[0105] Comparative Example 1 was repeated, except that the calcination was carried out at 700°C for 3 hours to obtain Comparative Catalyst 2.

[0106] Comparative Example 3

[0107] In a typical synthesis, 22.73 g of vanadium oxalate solution (11% V₂O₅ solid) was added to 100.0 g of DI water, and then mixed with 16.7 g of colloidal SiO₂ aqueous solution (30% SiO₂ solid). The mixture was stirred for 30 minutes, followed by the addition of 92.5 g of WO₃ / TiO₂ powder. The resulting paste was diluted with DI water. The resulting slurry was then coated onto a 400 / 6 honeycomb cordierite substrate and dried overnight at 120 °C, followed by calcination in air at 450 °C for 3 hours. After cooling to room temperature, comparative catalyst 3 was obtained.

[0108] SCR activity tests of catalysts 1 to 6

[0109] The catalysts were tested and compared according to the procedure described above, and the results of the activity tests are summarized in Table 3.

[0110] Table 3. SCR activity in comparative examples

[0111] The only difference between the preparation of catalyst 1 and catalyst 2 is that compound 1 was pretreated at 550°C for 20 hours before being mixed with other components. Catalyst 2 exhibited a significantly higher NOx conversion rate than catalyst 1. Similarly, catalyst 3 exhibited a higher NOx conversion rate than catalyst 2. It is speculated that TiO2, as a support, promotes or participates in the formation of vanadium- and antimony-containing composite oxides during high-temperature calcination, which enable the improved SCR activity of the catalyst composition.

[0112] Furthermore, the catalyst compositions according to the invention, or those obtained / available by the method according to the invention, even exhibit superior performance in SCR activity compared to comparative catalyst 3 (which is a typical commercially available SCR catalyst).

[0113] Although the invention has been described with respect to currently regarded exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A method for preparing a catalyst composition, said catalyst composition comprising: - TiO2-containing support, - A composite oxide containing vanadium and antimony, which exhibits properties different from VSbO4 and V 0.92 Sb 0.92 The rutile structure of O4 was determined by X-ray diffraction (XRD) analysis using Cu Kα radiation. The vanadium and antimony-containing composite oxide is characterized by an XRD diffraction peak at 27.25 on the (110) plane. o Up to 29.00 o The XRD diffraction peak at 2θ within the range and on the (101) plane is at 35.

43. o Up to 37.00 o At 2θ within the range, and - Optionally, one or more of silicon oxides, vanadium oxides and antimony oxides are selected; The method includes the following steps: (i) A suspension is obtained by mixing vanadium / antimony oxide and an optional silicon source with a TiO2-containing support in a solvent; (ii) Optionally, the suspension is applied to a substrate; (iii) Dry at a temperature ranging from 80 to 250°C; (iv) Calcination at a temperature of 600°C to 700°C, and The method further includes the preparation of the vanadium / antimony oxide used in step (i) as follows: (a) Provide a suspension containing vanadium oxide and antimony oxide; and (b) The suspension is dried at a temperature ranging from 80°C to 250°C to obtain vanadium / antimony oxide.

2. The method of claim 1, wherein the calcination in step (iv) is carried out at a temperature in the range of 650°C to 700°C.

3. The method according to claim 1 or 2, excluding step (ii) and optionally including a molding step to obtain a shaped catalyst composition.

4. The use according to any one of claims 1 to 3, wherein the vanadium and antimony-containing composite oxide is characterized in that the XRD diffraction peaks of the (110) or (101) plane are higher than those of VSbO4 and V. 0.92 Sb 0.92 O4 level is at least 0.1 o At 2θ.

5. The use according to claim 4, wherein the vanadium and antimony-containing composite oxide is characterized by XRD diffraction peaks on the (101) plane that are higher than those on VSbO4 and V. 0.92 Sb 0.92 O4 level is at least 0.2 ppm higher. o Preferably at least 0.3 o More preferably at least 0.5 o At 2θ.

6. The method according to any one of claims 1 to 5, wherein vanadium is present in the catalyst composition at 0.5 to 6 wt%, preferably 1 to 4.5 wt%, more preferably 2 to 4 wt%, calculated by element V, wherein the vanadium comprises vanadium in a vanadium- and antimony-containing composite oxide and optionally vanadium oxide; and wherein antimony is present in the catalyst composition at 0.8 to 16 wt%, preferably 3.5 to 14 wt%, more preferably 5 to 10 wt%, calculated by element Sb, wherein the antimony comprises antimony in a vanadium- and antimony-containing composite oxide and optionally antimony oxide.

7. A catalyst composition obtained / obtainable by the method according to any one of claims 1 to 6.

8. Use of the catalyst composition according to claim 7 for the selective catalytic reduction of nitrogen oxides.

9. The use according to claim 8, wherein the nitrogen oxides are present in exhaust gas from an internal combustion engine such as a diesel engine, a power plant, or an incinerator.

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