Zeolite composites and their use

Abstract

A composite material for treating NOx-containing exhaust gas, the composite material comprising a copper-substituted zeolite and one or more of Ti, Zr, Y, Ce, Er and Nd. In particular a copper-substituted CHA zeolite comprising 1 to 12 wt% Ti.

Description

Technical Field

[0001] This invention relates to zeolite composite materials, such as titanium chalcogenide (CHA) or titanium AEI. The invention also relates to a catalyst article comprising the composite material and a method for treating waste gas, the method comprising contacting the waste gas with the catalyst article comprising the composite material. Background Technology

[0002] Zeolites are crystalline or quasi-crystalline aluminosilicates composed of repeating TO4 tetrahedral units (or combinations of tetrahedral units), where T is most commonly Si, Al, or P. These units link together to form a framework within the crystal with regular cavities and / or molecular-sized channels. Many types of synthetic zeolites have been synthesized, and each zeolite possesses a unique framework based on a specific arrangement of its tetrahedral units. By convention, the International Zeolite Association (IZA) assigns a unique three-letter code (e.g., "CHA" or "AEI") to each topological type.

[0003] NH3-SCR is the most effective technology for reducing NOx in the aftertreatment of lean-burn engine exhaust gases. In this regard, Cu-SSZ-13 has been commercialized as an NH3-SCR catalyst due to its excellent catalytic performance and significant advantages in hydrothermal stability. SSZ-13 (skeleton type code CHA) is a high silica aluminosilicate zeolite, and Cu-SSZ-13 refers to a copper-supported zeolite, typically prepared by initial wet impregnation or ion exchange.

[0004] Wang et al. (Ind. Eng. Chem. Res. 2022, 61, 15066−15075) described the doping effects of transition metals (Fe, Ti, Mn, and Ce) on the structure and catalytic performance of Cu-SSZ-13 zeolite catalysts used in the NH3-SCR reaction. They found that transition metal doping via ion exchange leads to the substitution of Cu material at ion exchange sites by the dopant, increasing the likelihood of zeolite framework collapse. This results in relatively poor hydrothermal stability, lower low-temperature performance, and poor resistance to sulfur poisoning.

[0005] Zhang et al. (Microporous and Mesoporous Materials 255 (2018) 61-68) described the enhanced photocatalytic activity of TiO2 / zeolite composites for reducing contaminants. Characterization results illustrate the stabilization of anatase TiO2 nanoparticles on the surface of a zeolite support.

[0006] Yue Ma et al. (React.Chem.Eng., 2022, 7, 2121) described the combination of Cu-SSZ-13 and TiO2 nanoparticles by a simple impregnation method.

[0007] Wan, J., Chen, J., Shi, Y., et al. (Catal Surv Asia 26, 346-357 (2022)) describe a series of Ti / Cu-SSZ-13 zeolite catalysts. These catalysts exhibit variable Ti content and are prepared via an in-situ one-pot synthesis strategy.

[0008] US9,889,437 describes an SCR catalyst comprising a zeolite with a framework of silicon and aluminum atoms, wherein some of the silicon atoms are isomorphously replaced by Ti.

[0009] There is still a need in the art for alternative methods and new catalysts for treating waste gases, especially those exhibiting improved NO reduction. x Conversion rate and selectivity (e.g., fresh or aged at low temperatures) for NO x Selective catalytic reduction of NO x Those that reduce the amount of catalyst. Summary of the Invention

[0010] One aspect of the present invention relates to a composite material for treating NOx-containing waste gas, the composite material comprising copper-substituted zeolite and one or more of Ti, Zr, Y, Ce, Er and Nd.

[0011] Another aspect of the present invention is a catalyst article for treating waste gas, the catalyst article comprising a composite material as described herein.

[0012] Another aspect of the invention relates to a method for treating waste gas, the method comprising contacting the waste gas with a catalyst article described herein.

[0013] Another aspect of the present invention relates to a method for manufacturing a composite material comprising zeolite and one or more of Ti, Zr, Y, Ce, Er, and Nd, the method comprising:

[0014] (i) providing a composition comprising zeolite and one or more inorganic compounds selected from Ti, Zr, Y, Ce, Er, and Nd, the composition having a pH of less than 7; and

[0015] (ii) Adding an alkali to the composition to increase the pH of the composition and produce a composite material;

[0016] Zeolites have a CHA or AEI framework.

[0017] Another aspect of the invention relates to a composite material that can be produced by the above method, the composite material comprising (bare) zeolite and one or more of Ti, Zr, Y, Ce, Er and Nd (preferably titanium), wherein the zeolite has a CHA or AEI framework.

[0018] Another aspect of the invention relates to intermediates produced during the method of the invention.

[0019] Another aspect of the invention relates to the use of titanium for improving the selectivity (lower N2O production) of copper chalcogenide SCR catalysts. Attached Figure Description

[0020] Figure 1 The NOx conversion and N2O selectivity of Ti Cu zeolite according to an embodiment of the present invention, as well as that of Ti-free comparative Cu zeolite, are shown.

[0021] Figure 2 The changes in NH3, NO, and N2O over time are shown for Ti Cu zeolite according to an embodiment of the present invention, as well as for Ti-free comparative Cu zeolite.

[0022] Figure 3 Ti-Cu zeolite according to an embodiment of the invention is shown, as well as H2-TPR (hydrogen temperature programmed reduction) of a Ti-free comparative Cu zeolite.

[0023] Figure 4 shows a TEM image of Ti zeolite (Cu-free) (Ti content approximately 1.5% according to ICP) according to an embodiment of the present invention. The scale is 50 nm.

[0024] Figure 5 shows a TEM image of Ti-Cu zeolite (Ti content approximately 1.5% and Cu content approximately 3.5% according to ICP) according to an embodiment of the present invention. The scale is 50 nm.

[0025] Figure 6 shows the NOx conversion (A) and N2O production (B) of Ti Cu zeolite and Ti-free comparative Cu zeolite according to an embodiment of the present invention at 200 °C. Detailed Implementation

[0026] One aspect of the invention relates to a composite material for treating NOx-containing waste gas, the composite material comprising copper-substituted zeolite and one or more of Ti, Zr, Y, Ce, Er and Nd (e.g., substantially composed of or composed of them).

[0027] N2O is an SCR process used to remove NOx (also known as NO removal). xUndesirable byproducts of the process. High NOx removal performance is required at high temperatures (T > 450°C) without undesirable ammonia oxidation reactions. Compared to reference copper zeolites that do not contain one or more of Ti, Zr, T, Ce, or Nd, the composites of the present invention exhibit improved selectivity and NOx performance.

[0028] The composite material of the present invention exhibits improved selectivity for both fresh and hydrothermally aged catalysts over a wide temperature range (150°C to 550°C) and improved high-temperature NO removal. x performance.

[0029] Preferably, the composite material exhibits low N2O selectivity. N2O selectivity is defined as the number of moles of N2O formed divided by the number of NO converted. x The number of moles of NOx (NOx is defined as NO and NO2). Lower N2O selectivity is an improved N2O selectivity and is desirable because it is necessary to reduce N2O formation, i.e., greenhouse gas. Figure 1 The improved N2O selectivity (lower N2O generation) of titanium copper zeolite compared to a titanium-free reference copper zeolite is shown.

[0030] This invention covers the manufacture of composites comprising copper-substituted zeolites and one or more of Ti, Zr, Y, Ce, Er, and Nd (e.g., substantially composed of or composed of them). This invention does not relate to copper-substituted zeolites having a framework of Ti, Zr, Y, Ce, Er, and / or Nd. Specifically, the composites of this invention do not contain framework titanium (also known as titanate zeolites), i.e., where Ti is part of the zeolite framework structure. The copper-substituted zeolites of this invention have repeating TO4 tetrahedral units, where T is Si and Al, i.e., aluminosilicate zeolites. The inventors propose that Ti, Zr, Y, Ce, Er, and / or Nd (preferably titanium) are present on the surface of the zeolite (e.g., as TiO2 nanoparticles) and / or in ion exchange sites within the zeolite. The composites may comprise aluminosilicate particles with a porous TiO2 coating, e.g., zeolite particles encapsulated in titanium dioxide, as illustrated in Figures 4 and 5. The TiO2 coating is understood to be porous because it does not prevent copper loading. This disclosure will now be described further. In the following paragraphs, different aspects / implementations of this disclosure are defined in more detail. Unless expressly stated to the contrary, each aspect / implementation so defined may be combined with any other aspect / implementation or multiple aspects / implementations. In particular, any feature indicated as preferred or advantageous may be combined with one or more other features indicated as preferred or advantageous.

[0031] One aspect of the invention relates to a method for manufacturing a composite material comprising (bare) zeolite and one or more of Ti, Zr, Y, Ce, Er, and Nd (preferably titanium) (e.g., substantially composed of or composed of these), the method comprising:

[0032] (ii) A composition comprising one or more inorganic compounds (preferably inorganic titanium compounds) selected from Ti, Zr, Y, Ce, Er, and Nd, zeolite, and water, the composition having a pH of less than 7; and

[0033] (ii) Adding an alkali to the composition to increase the pH of the composition and produce a composite material;

[0034] Zeolites have a CHA or AEI framework.

[0035] It should be understood that copper can be added to the direct product of this method to produce the composite material of the first aspect of the invention. This can be done, for example, by initial wet impregnation or ion exchange.

[0036] One or more inorganic compounds selected from Ti, Zr, Y, Ce, Er, and Nd are preferably not oxides. The inorganic compounds can be sulfates, acetates, or nitrates, and can form oxides within the composition. Unbound by theory, the inventors propose that in-situ formation of oxides provides a more catalytically active composite material.

[0037] In this embodiment, the composite material is prepared by first combining a (bare, i.e., Cu-free) zeolite with an inorganic compound under acidic conditions. Preferably, the zeolite is an H-type zeolite, wherein H+ (protons) occupy ion exchange sites within the zeolite, rather than, for example, a copper-loaded zeolite. The copper-loaded composite material can be obtained through subsequent processing of the Ti zeolite composite material, for example, via an ion exchange step. We believe that the order in which copper is added affects the structure of the resulting composite material (e.g., Cu morphology formation). Therefore, the copper-loaded composite material of the present invention can be distinguished from prior art composite materials that use titanium after copper.

[0038] In one embodiment, the starting composition (before the addition of a base) comprises an inorganic titanium compound (e.g., titanium oxysulfate), a zeolite (e.g., CHA or AEI zeolite), an optional acid (e.g., sulfuric acid), and water, and has a pH less than 7. The pH can be adjusted by changing the concentration of the acid. The pH can be 6 or less, 5.5 or less, 5 or less, 4 or less, 3 or less, or 2 or less.

[0039] In one embodiment, the starting composition (before the addition of a base) comprises an inorganic zirconium compound (e.g., zirconium acetate (IV)), a zeolite (e.g., CHA or AEI zeolite), an optional acid (e.g., acetic acid), and water, and has a pH less than 7. The pH can be adjusted by changing the concentration of the acid. The pH can be 6 or less, 5.5 or less, 5 or less, 4 or less, 3 or less, or 2 or less.

[0040] In one embodiment, the starting composition (before the addition of a base) comprises an inorganic yttrium compound (e.g., yttrium acetate), a zeolite (e.g., CHA or AEI zeolite), an optional acid (e.g., acetic acid), and water, and has a pH less than 7. The pH can be adjusted by changing the concentration of the acid. The pH can be 6 or less, 5.5 or less, 5 or less, 4 or less, 3 or less, or 2 or less.

[0041] In one embodiment, the starting composition (before the addition of a base) comprises an inorganic cerium compound (e.g., cerium nitrate), a zeolite (e.g., CHA or AEI zeolite), an optional acid (e.g., nitric acid), and water, and has a pH less than 7. The pH can be adjusted by changing the concentration of the acid. The pH can be 6 or less, 5.5 or less, 5 or less, 4 or less, 3 or less, or 2 or less.

[0042] In one embodiment, the starting composition (before the addition of a base) comprises an inorganic erbium compound (e.g., erbium acetate), a zeolite (e.g., CHA or AEI zeolite), an optional acid (e.g., acetic acid), and water, and has a pH less than 7. The pH can be adjusted by changing the concentration of the acid. The pH can be 6 or less, 5.5 or less, 5 or less, 4 or less, 3 or less, or 2 or less.

[0043] In one embodiment, the starting composition (before the addition of a base) comprises an inorganic neodymium compound (e.g., neodymium acetate or neodymium nitrate), a zeolite (e.g., CHA or AEI zeolite), an optional acid (e.g., acetic acid or nitric acid), and water, and has a pH less than 7. The pH can be adjusted by changing the concentration of the acid. The pH can be 6 or less, 5.5 or less, 5 or less, 4 or less, 3 or less, or 2 or less.

[0044] The acid can be an inorganic acid, such as sulfuric acid (H₂SO₄), hydrochloric acid (HCl), or nitric acid (HNO₃). Since the composition contains water, the acid is an aqueous acid.

[0045] Zeolites are typically aluminosilicate zeolites, which have a framework composed essentially of aluminum, silicon, and oxygen. Zeolites may have a silica-to-alumina molar ratio (SAR) of 5 or greater, 10 or greater, or 15 or greater, and / or a silica-to-alumina molar ratio (SAR) of 40 or less, 30 or less, or 20 or less. Zeolites may have SARs of 15 to 25, such as 18 to 23, such as 19, 20, 21, or 22. Zeolites may include chabazite (CHA) and / or AEI zeolite.

[0046] In a preferred embodiment, the zeolite has a silica to alumina molar ratio (SAR) of 10 to 30, preferably 12 to 28, more preferably 14 to 25. In another embodiment, the SAR is 12 to 16 (e.g., 14), 18 to 22 (e.g., 20), or 22 to 27 (e.g., 25). In a particularly preferred embodiment, the SAR is 10 to 25, preferably 12 to 22, and even more preferably 13 to 21.

[0047] Inorganic titanium compounds can be titanium oxysulfate (TiOSO4). Titanium oxysulfate hydrolyzes to form a gel of hydrated titanium dioxide. The method may include an initial step of forming a composition by combining titanium oxysulfate with zeolite, optionally an acid, and water.

[0048] The starting composition may be described with reference to the total dry weight of the inorganic titanium compound and the zeolite. The inorganic titanium compound may comprise at least 3% by weight, at least 5% by weight, at least 7% by weight, or at least 10% by weight of the total dry weight of the inorganic titanium compound and the zeolite. The inorganic titanium compound may comprise 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, or 10% by weight or less of the total dry weight of the inorganic titanium compound and the zeolite.

[0049] Similarly, the composition can be described by referring to the ratio of the dry weight of the inorganic titanium compound to the dry weight of the zeolite, for example, 1:20 to 1:1, such as 1:15 to 1:5, such as 1:10.

[0050] The addition of an alkali increases the pH of the composition, thereby producing a composite material, such as a white residue of zeolite and titanium. The alkali may include ammonia, for example, ammonia solution. The addition of an alkali can increase the pH of the composition to pH 3.5 or higher, pH 4 or higher, or pH 4.5 or higher, such as pH 3 to 7 or pH 4 to 6.

[0051] The composite material can be separated from the rest of the composition, for example, by filtration. The composite material can be dried, for example, at a temperature of 100°C to 200°C for a period of 1 to 10 hours. The composite material can be calcined, for example, at a temperature of 500°C to 1000°C for a period of 1 to 5 hours.

[0052] In one implementation, the method includes:

[0053] (i) Provides a composition comprising aqueous sulfuric acid (H2SO4) and zeolite, the composition having a pH less than 7, and the zeolite comprising zeolite particles having an outer surface; and

[0054] (ii) Adding titanium oxysulfate (TiOSO4) and a base to the composition increases the pH of the composition and deposits titanium dioxide (TiO2) on the outer surface of the zeolite particles.

[0055] Zeolites have a CHA or AEI framework.

[0056] In some preferred embodiments, the method further includes the step of adding iron and / or copper to the composite material via ion exchange. As described herein, iron and / or copper-exchanged zeolites are particularly preferred as NH3-SCR catalysts.

[0057] In another embodiment, the present invention relates to a method for preparing a composite material (e.g., a composite material as described herein), the method comprising:

[0058] (i) First, one or more of Ti, Zr, Y, Ce, Er and Nd (preferably Ti) are exchanged into the molecular sieve, and then...

[0059] (ii) Secondly, copper is incorporated into the molecular sieve.

[0060] The exchange of one or more of Ti, Zr, Y, Ce, Er and Nd (preferably Ti) can be carried out by any known technique (such as ion exchange, impregnation, isomorphous substitution, etc.). Preferably, the exchange of one or more of Ti, Zr, Y, Ce, Er and Nd, preferably Ti, is performed by ion exchange.

[0061] The present invention also relates to a composite material that can be produced by the above method. The composite material is an intermediate for the preparation of copper-substituted products and comprises (bare) zeolite and one or more of titanium, zirconium, yttrium, cerium, erbium, and neodymium, wherein the zeolite has a CHA or AEI framework.

[0062] In some embodiments, the composite material comprises CHA zeolite having a SAR of 10 to 30, 15 to 25, 18 to 20, preferably 12 to 28, and more preferably 14 to 25. In another embodiment, the SAR is 12 to 16 (e.g., 14), 18 to 22 (e.g., 20), or 22 to 27 (e.g., 25). In a particularly preferred embodiment, the SAR is 10 to 25, preferably 12 to 22, and even more preferably 13 to 21. In other embodiments described herein, the composite material comprises AEI zeolite having a SAR of 10 to 30, 15 to 25, 18 to 20, preferably 12 to 28, and more preferably 14 to 25. In another embodiment, the SAR is 12 to 16 (e.g., 14), 18 to 22 (e.g., 20), or 22 to 27 (e.g., 25). In a particularly preferred embodiment, the SAR is 10 to 25, preferably 12 to 22, and even more preferably 13 to 21.

[0063] The composite material may contain one or more of Ti, Zr, Y, Ce, Er, and Nd, with a total loading of at least 0.5 wt% based on oxides, preferably at least 1 wt% based on oxides, such as from 0.5 wt% to 10 wt% based on oxides. In one embodiment, the composite material contains one or more of Ti, Zr, Y, Ce, Er, and Nd, with a total loading of from 0.5 wt% to 15 wt% based on oxides, preferably from 1 wt% to 10 wt% based on oxides, and most preferably from 2 wt% to 7 wt% based on oxides.

[0064] Preferably, the composite material comprises titanium, with a loading of at least 0.5 wt% based on oxides, preferably at least 1 wt% based on oxides, such as from 1 wt% to 10 wt% based on oxides. The Ti composite material may contain at least 0.5 wt% TiO2, preferably at least 1 wt% TiO2, such as from 1 wt% to 10 wt% TiO2. The Ti composite material may contain 10 wt% or less TiO2, such as 5 wt% or less TiO2, such as 3 wt% or less TiO2. Examples illustrate composite materials with 1.3 wt% TiO2 and composite materials with 2.6 wt% TiO2.

[0065] The composite material of the present invention may contain copper in a loading of 2 wt% or more, 3 wt% or more, 4 wt% or more, or 5 wt% or more, such as 2 wt% to 5 wt% Cu. In particular, the composite material may contain CHA zeolite (e.g., SAR 10-30, 12-28, 14-25, or 18-20) having a titanium loading of 1 wt% to 3 wt% and a copper loading of 3 wt% to 5 wt%.

[0066] In one aspect, the composite material of the present invention as described herein does not contain Mn, preferably does not contain Mn or Fe, more preferably does not contain Mn, Fe or Si, even more preferably does not contain Mn, Fe, Si, Ce or Sn, and most preferably does not contain Mn, Zr, Fe, Si, Ce or Sn.

[0067] In another aspect of the invention, a catalyst article for treating waste gas is provided, the catalyst article comprising a composite material as described herein.

[0068] In another aspect, a method for treating waste gas is provided, the method comprising contacting the waste gas with a catalyst article described herein.

[0069] In another aspect of the invention, a method for reducing exhaust gases (e.g., those containing NO) is provided. x A method for N2O formation in the catalytic treatment of ammonia waste gas, wherein the waste gas is contacted with the composite material described herein, the catalyst article described herein (e.g., a catalyst article containing the composite material as described herein), or the composite material produced by the method described herein.

[0070] The method may also include making NO-containing x The waste gas, including optional NH3, is contacted with the catalyst described herein to remove NO. x At least a portion of the nitrogen oxides are selectively reduced to N2 and H2O and at least a portion of NH3 (if present) is oxidized. Therefore, in one embodiment, the catalyst article can be formulated to facilitate the reduction of nitrogen oxides with a reducing agent (i.e., an SCR catalyst). Examples of such reducing agents include hydrocarbons (e.g., C3-C6 hydrocarbons) and nitrogen-containing reducing agents such as ammonia and hydrazine ammonia or any suitable ammonia precursor such as urea ((NH2)2CO), ammonium carbonate, ammonium carbamate, ammonium bicarbonate, or ammonium formate.

[0071] In another embodiment of the invention, the exhaust gas may be generated by an internal combustion engine powered by a fuel mixture comprising: an air-containing fuel mixture; and hydrogen and / or ammonia, also known as a hydrogen internal combustion engine or an ammonia internal combustion engine.

[0072] This invention also applies to the removal of NO from exhaust gases produced by internal combustion engines powered by hydrogen and / or ammonia fuels. x reduce.

[0073] Hydrogen internal combustion engines are well known to those skilled in the art and can be considered improved versions of conventional gasoline (petroleum) or diesel-powered internal combustion engines. The fuel in the air-fuel mixture is a gaseous fuel containing hydrogen (H2) as the majority of its mass. Preferably, internal combustion engines configured to operate with hydrogen (H2) as the primary fuel mass are configured to operate with fuels containing >70% by volume of H2, such as >90% by volume, >95% by volume, >99% by volume of H2, and more preferably fuels consisting essentially of H2. The balance of the fuel mass may consist of hydrocarbons such as methane, diesel, and / or gasoline.

[0074] Although hydrogen internal combustion engines can operate with virtually no carbon-based emissions (e.g., CO or CO2) or unburned hydrocarbons (HC) in their exhaust, some trace emissions may still be present due to the combustion of engine additives such as lubricating oil. However, unburned hydrogen in the exhaust remains a concern for hydrogen internal combustion engines, as does NO produced by the combustion of fuel in air (which is approximately 78% nitrogen by volume). x This is also true, as is known in conventional internal combustion engines. Additionally, the exhaust gases from hydrogen internal combustion engines are typically colder than those from gasoline or diesel engines. This can affect the efficiency of catalytic aftertreatment of H2 and NOx in the exhaust gases, and also impacts remedial processes such as the selective catalytic reduction (SCR) desulfurization process used in diesel exhaust systems, which requires relatively high temperatures and sometimes a reducing atmosphere for desulfurization. Furthermore, hydrogen internal combustion engines produce a relatively large amount of water as a combustion byproduct. Typically, hydrogen internal combustion engine exhaust gases can contain approximately 20% to 30% water by volume as vapor.

[0075] Similarly, ammonia (NH3) is also considered for direct use as a fuel in combustion systems, or as a highly efficient hydrogen carrier. Emissions from ammonia combustion may contain N2O and NO. X And unburned ammonia. In addition, the water content in the exhaust gas produced by the combustion of ammonia will be significantly higher than that emitted by conventional gasoline (petroleum) or diesel-powered internal combustion engines.

[0076] Known SCR catalysts can be used to remove NO from the exhaust gases of hydrogen internal combustion engines and / or ammonia internal combustion engines. x However, the relatively high water content in the exhaust gases of hydrogen or ammonia internal combustion engines adversely affects the activity of conventional SCR catalysts, leading to reduced catalyst activity and performance. The presence of water inhibits NO production due to adsorption at the active sites of the catalyst. xConversion rate. Water adsorbed on the catalyst surface hinders the adsorption of reactants, and the separated adsorbed hydroxyl (OH) groups derived from water may reduce the reactivity of active sites, thereby reducing catalytic activity. Surprisingly, the inventors of this invention have discovered that the catalyst article according to the invention exhibits improved catalytic activity when treating exhaust gases with relatively high water content, and therefore exhibits improved NO conversion. x Conversion rate. Without being bound by any theory, it is believed that when treating exhaust gases in the presence of water, the presence of one or more of Ti, Zr, Y, Ce, Er, and Nd (preferably titanium) reduces catalyst deactivation, thereby leading to improved NO conversion. x Conversion rate and improved selectivity (lower N2O generation).

[0077] Therefore, in another aspect of the invention, a system for treating exhaust gas generated by a hydrogen internal combustion engine or an ammonia internal combustion engine is provided, wherein the exhaust gas contains NOx, and wherein the system comprises:

[0078] Hydrogen internal combustion engine or ammonia internal combustion engine;

[0079] The catalyst products described herein; and

[0080] The reducing agent source is located upstream of the catalyst product.

[0081] Another advantage of the catalyst articles in this aspect of the invention is that copper-substituted zeolite SCR catalysts are more resistant to sulfur, i.e., they are less prone to sulfation, or if sulfation occurs, they retain relatively higher activity than alternative SCR catalysts. Therefore, the catalyst articles may require less frequent desulfurization events to maintain their activity, thereby improving the overall fuel economy of the system; that is, less frequent energy is required to raise the catalyst temperature, and optionally, less frequent enrichment of hydrogen reductant in the exhaust gas is required to desulfurize the catalyst.

[0082] In another aspect of the invention, a method for reducing N2O formation in the catalytic treatment of exhaust gases from hydrogen or ammonia internal combustion engines is provided, wherein the exhaust gases are contacted with a composite material described herein, a catalyst article described herein (e.g., a catalyst article comprising a composite material as described herein), or a composite material produced by a method as described herein.

[0083] As illustrated in the examples, the inventors have found that the method described above is unexpectedly effective in reducing the formation of nitrous oxide (N2O) during the treatment of exhaust gases from hydrogen engines.

[0084] Examples

[0085] General procedure

[0086] Bare composite materials (copper-free) were prepared according to a method adapted by Zhang et al. (Microporous and Mesoporous Materials 255(2018)61-68). Zeolite (AZM16 = CHA with SAR 19) was mixed with a solution of titanium oxysulfate (IV) (equivalent to deionized water and sulfuric acid), and then ammonia solution was added to adjust the pH to 4.5. A white residue formed, which was washed with distilled water, dried at 105 °C for 8 hours, and calcined at 650 °C for 2 hours. In-situ, 5 wt% or 10 wt% TiO2 equivalents were generated using titanium oxysulfate (IV). TiO2-based ICP (inductively coupled plasma) spectroscopy imparted 1.3% and 2.6% Ti to the resulting composite materials, respectively.

[0087] The calcined composite material is loaded with copper (3% or 4% by weight) through ion exchange.

[0088] The composite material was tested in fresh (F500C / 2h) powder and in powder form after HDD aging conditions (LHA650C / 50h) under the following conditions: i) NO and NH3 in O2 (10%) + H2O (8%) (ANR 1.1), T = 150°C to 500°C, heating rate = 5°C / min, SV 60 kh-1; ii) NO (500 ppm, CO (350 ppm), CO2 (8%), O2 (10%), H2O (8%), at 175°C, NH3 (700 ppm) injected after 5 min, with a total SV of 60 kh-1.

[0089] refer to Figure 1 and Figure 2 For copper-substituted chabazite (3 wt% Cu) with and without Ti, NO0 is produced before approximately 400°C. x The conversion rates are similar. The composite material of the present invention maintains a high NOx conversion rate above approximately 400°C. Furthermore, the titanium-containing composite material exhibits lower N2O throughout the entire temperature range. Therefore, the composite material of the present invention shows a significant improvement in selectivity (lower N2O formation) across the entire experimental temperature range (150°C to 500°C). This surprising benefit is not due to, as... Figure 3 The small differences in Cu loading are shown. H2-TPR confirmed the minimal differences in Cu loading and morphology. In fact, the Cu loading was estimated by reduction with NO and NH3, and Ti-containing products were found to be 2.9% by weight, compared to 3.1% by weight in the reference sample (without titanium).

[0090] The same Ti-doped CHA SAR 19 material was exchanged with 4% Cu and formulated into a carrier coating, and then coated (2.4 g / in). 3 It was incorporated into a honeycomb cordierite substrate for activity testing in monolithic form. The same benefits in selectivity and high-temperature NOx removal performance were observed after LHA650C / 50h. Beneficial effects were retained after hydrothermal aging.

[0091] TEM images of Ti-containing zeolite (Cu-free) show the presence of Ti (Ti) on the surface of the zeolite particles. Figures 4A to 4C TEM images of Ti-containing copper-substituted zeolites show the presence of Ti on the surface of the zeolite particles and the presence of copper within the particles. Figure 5A (See Figure 4D).

[0092] H2-ICE test

[0093] The composite material was also tested under H2-ICE conditions. For this type of application, exhaust gas treatment must be carried out under more demanding conditions, namely, higher moisture content in the exhaust gas feed, which may affect NOx reduction performance and selectivity. Therefore, improved NOx conversion and selectivity remain desirable characteristics for alternative methods of exhaust gas treatment and new catalysts.

[0094] The composite material in fresh (F500C / 2h) powder form was tested under the following conditions: i) NO and NH3 (ANR 1.1) in O2 (10%) + H2O (20 vol% H2O). T = 150 °C to 500 °C, heating rate = 5 °C / min, SV = 60 kh⁻¹. The results of this test were compared with those obtained in the presence of 10 vol% H2O.

[0095] refer to Figure 6A and Figure 6B For two sets of conditions (10 vol% H2O and 20 vol% H2O), for copper-substituted chabazite (3 wt% Cu) with and without Ti, NO x The conversion rates were similar at 200°C. For both catalysts, the NOx conversion rate was slightly affected by the increased water content in the feed. However, the titanium-containing composite exhibited lower N2O production. Therefore, the composite of the present invention maintains a significant improvement in selectivity (lower N2O production) even under more demanding conditions, such as those anticipated for H2-ICE applications.

[0096] As used herein, unless the context clearly indicates otherwise, the singular forms “an,” “a,” and “the / described” include plural references. The term “comprising” is intended to be interpreted as including such features but not excluding others, and also as including feature options that must be limited to those features described. In other words, the term also includes the limitations “consistently made of” (intended to indicate the presence of specific additional components provided they do not substantially affect the essential characteristics of the described feature) and “composed of” (intended to indicate that other features may be excluded such that, if these components were expressed as percentages of their proportions, they would total 100%, taking into account any unavoidable impurities), unless the context clearly indicates otherwise.

[0097] The phrase "consisting essentially of..." refers to the fundamental and novel feature of this invention: a composite material comprising copper-substituted zeolite and one or more of Ti, Zr, Y, Ce, Er, and Nd. Adding other metals to the copper-substituted zeolite can affect the NO content of the resulting catalyst. x Conversion rate and selectivity, and thus do not constitute part of the essential and novel features of the invention. For example, in one aspect, the composite material of the invention as described herein does not contain Mn, preferably does not contain Mn or Fe, more preferably does not contain Mn, Fe or Si, even more preferably does not contain Mn, Fe, Si, Ce or Sn, and most preferably does not contain Mn, Zr, Fe, Si, Ce or Sn.

[0098] The detailed description above has been provided by way of explanation and illustration and is not intended to limit the scope of the appended claims. Many variations of the presently preferred embodiments shown herein will be apparent to those skilled in the art and remain within the scope of the appended claims and their equivalents.

Claims

1. A composite material for treating NOx-containing waste gas, said composite material comprising copper-substituted zeolite and one or more of Ti, Zr, Y, Ce, Er and Nd.

2. The composite material according to claim 1, wherein the composite material comprises titanium.

3. The composite material according to claim 2, wherein the composite material comprises Ti based on an oxide of at least 0.5 wt%, preferably Ti based on an oxide of 1 wt% to 5 wt%.

4. The composite material according to any one of the preceding claims, wherein the copper-substituted zeolite has a CHA or AEI framework.

5. The composite material according to any one of the preceding claims, wherein the copper-substituted zeolite has a CHA framework and 10 to 30 or 15 to 20, preferably 12 to 28, more preferably 14 to 25 SAR.

6. The composite material according to any one of the preceding claims, wherein the composite material comprises 1 wt% to 6 wt% Ti and 2 wt% to 4 wt% Cu.

7. A catalyst article for treating waste gas, said catalyst article comprising a composite material according to any one of the preceding claims.

8. A method for treating waste gas, the method comprising contacting the waste gas with a composite material according to any one of claims 1 to 6 or a catalyst article according to claim 7.

9. A system for treating NOx-containing waste gas, the system comprising a catalyst article according to claim 7 and a reducing agent source, wherein the reducing agent source is upstream of the catalyst article.

10. A method for manufacturing a composite material comprising zeolite and titanium, the method comprising: (i) Provides a composition comprising zeolite and one or more inorganic compounds selected from Ti, Zr, Y, Ce, Er and Nd, said composition having a pH of less than 7; as well as (ii) Adding an alkali to the composition to increase the pH of the composition and produce the composite material; The zeolite described therein has a CHA or AEI framework.

11. The method of claim 10, further comprising the step of loading Cu into the zeolite, preferably by ion exchange.

12. The method according to claim 10 or 11, wherein the composition comprises an inorganic compound of titanium, preferably titanium oxysulfate.

13. The method according to claim 10 or 11, wherein the composition comprises (i) Inorganic compounds of zirconium, preferably zirconium sulfate; (ii) Inorganic compounds of yttrium, preferably yttrium acetate; (iii) Inorganic compounds of cerium, preferably cerium nitrate; (iv) Inorganic compounds of erbium, preferably erbium acetate; and / or (v) Inorganic compounds of neodymium, preferably neodymium nitrate.

14. A composite material that can be produced by the method according to any one of claims 10 to 13, wherein the zeolite has a CHA or AEI skeleton.

15. Use of titanium to reduce the N2O selectivity of copper chalcogenide zeolite catalysts, whereby N2O selectivity is defined as the number of moles of N2O formed divided by the amount of NO converted. x The number of moles.

16. A method for reducing N2O formation in the catalytic treatment of exhaust gas, the method comprising contacting the exhaust gas with a catalyst article according to claim 7, a composite material according to any one of claims 1 to 6, or a composite material produced by the method according to any one of claims 10 to 14.

17. The method of claim 16, wherein the exhaust gas is generated by a hydrogen internal combustion engine or an ammonia internal combustion engine.

18. A method for preparing a composite material (e.g., a composite material according to any one of claims 1 to 6), the method comprising: (i) First, one or more of Ti, Zr, Y, Ce, Er and Nd (preferably Ti) are exchanged into the molecular sieve, and then... (ii) Next, copper is incorporated into the molecular sieve.

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