LEV zeolite compositions for selective catalytic reduction

Abstract

LEV zeolites having low silica-to-alumina ratios and high Cu loadings. The LEV zeolites are configured for use as selective catalytic reduction catalysts. The LEV zeolites may include a silica-to-alumina ratio (SAR) between about (8) and about (20) and a Cu component present in an amount of about 4.0 wt. % to about 8.0 wt. %.

Description

230013 WOO 1 ZECM-23 - 1370WOLEV ZEOLITE COMPOSITIONS FOR SELECTIVE CATALYTIC REDUCTIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. provisional patent application No. 63 / 767,035, filed March 5, 2025, and to U.S. provisional patent application No. 63 / 699,997, filed September 27, 2024, the disclosures of which are hereby incorporated by reference in their entirety.BACKGROUND

[0002] There is an urgent and unaddressed societal imperative of fostering a cleaner environment conducive to a more sustainable society. The detrimental environmental effects of fossil fuel combustion, such as the emissions of carbon dioxide (CO2) and nitrogen oxide (NO.V: N2O, NO and NO2), are significant. CO2 emissions are the primary culprits of anthropogenic global warming, which is responsible for the substantial financial obligation of industrial carbon taxes. In addition, NO.V, another influential greenhouse gas, serves as a key precursor to the production of the fine particulate matter (PM2.5; size of 2.5 pm or below) and ozone.

[0003] For NH3 selective catalytic reduction (SCR) catalysts, in addition to having high NOXreduction (deNOx) capability, reduced N2O byproduct formation and higher stability against sulfur species formed during fuel combustion are some of the desired aspects for fulfilling environmental regulations and to mitigate pollution for a sustainable society. There is a need for improvements in the synthesis of zeolite compositions with improved deNOx and N2O formulation capabilities.

[0004] The need for more sustainable energy sources is leading to internal combustion engine (ICE) platforms that utilize unconventional fuels, such as flexible fuel engines. Key examples include engines that utilize NH3, H2, compressed natural gas (CNG), or oxygenated hydrocarbons as the fuel source. Methanol and ethanol are examples of oxygenated hydrocarbon of interest.

[0005] In diesel emission systems, it is also desirable to eliminate the ammonia before it can pass into the tailpipe. A selective ammonia oxidation (AMOx) catalyst is employed for this purpose, with the objective to convert the excess ammonia to N2. It would be desirable that the AMOx catalyst should also produce minimal N2O, which is a potent greenhouse gas. Ideally, an AMOx catalyst should exhibit both high NH3 oxidation activity and high selectivity to N2. However, most of the known AMOx catalysts display a trade-off relationship for activity and1ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO selectivity, i.e., higher NH3 oxidation activity is accompanied by a lower N2 selectivity (higher level of undesirable byproduct, such as N2O and NO).

[0006] Generally, the AMOx catalyst comprises an SCR catalyst such as metal supported zeolites in addition to other components. The function of this zeolite component is to store ammonia by adsorption and to carry out SCR for the nitrogen oxides generated upon oxidation of ammonia in the AMOx catalyst.SUMMARY

[0007] In one embodiment, a selective catalytic reduction (SCR) catalyst for the abatement of nitrogen oxides (NOx) in an exhaust gas stream includes an LEV zeolite having a silica-to- alumina ratio (SAR) between about 8 and about 20 and a Cu component, wherein the Cu component is present in an amount of about 2.0 wt. % to about 8.0 wt. % calculated as CuO.

[0008] In one embodiment, the LEV zeolite has an SAR of about 10 to about 18.

[0009] In one embodiment, the LEV zeolite has an SAR of about 10 to about 15.

[0010] In one embodiment, the Cu component is present in an amount greater than about 5 wt. % calculated as CuO.

[0011] In one embodiment, the Cu component is present in an amount of about 4.0 wt. % to about 8.0 wt. % calculated as CuO.

[0012] In one embodiment, the LEV zeolite includes a Cu to Al ratio of about 0.30 to about 0.60.

[0013] In one embodiment, the LEV zeolite includes a Cu to Al ratio of about 0.35 to about 0.50.

[0014] In one embodiment, the LEV zeolite includes a Cu to Al ratio greater than about 0.40.

[0015] In one embodiment, the LEV zeolite comprises a secondary component including one or more of Fe, Ce, Mn, and Zn.

[0016] In one embodiment, a method of removing nitrogen oxides (NOx) from an exhaust stream includes providing the SCR catalyst of any one of the above embodiments; and contacting the SCR catalyst with an exhaust stream wherein the exhaust stream comprises NOx.

[0017] In one embodiment, the exhaust stream is from an internal combustion engine.

[0018] In one embodiment, a fuel used in the internal combustion engine includes liquid hydrocarbon, oxygenated hydrocarbon, compressed natural gas, NH3 or H2.

[0019] In one embodiment, the exhaust stream has a NO2 to NOx ratio of 0 to less than 0.99.

[0020] In one embodiment, a method for reducing NOx emissions in an exhaust gas includes providing the SCR catalyst of any one of the above embodiments; contacting an exhaust gas 2ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO including NH3 and an inlet NO concentration with the SCR catalyst; and producing a purified gas containing an outlet NO concentration and an outlet N2O concentration, wherein the ratio of the inlet NO concentration to the outlet N2O concentration is greater than about 60.

[0021] In one embodiment, the ratio of the inlet NO concentration to the outlet N2O concentration is greater than about 90.

[0022] In one embodiment, the ratio of the inlet NO concentration to the outlet N2O concentration is greater than about 120.

[0023] In one embodiment, an ammonia oxidation (AMOx) catalyst includes an LEV zeolite including a silica-to-alumina ratio (SAR) between about 8 and about 20 and a Cu component, wherein the Cu component is present in an amount of about 2.0 wt. % to about 8.0 wt. % calculated as CuO.

[0024] In one embodiment, the LEV zeolite has an SAR of about 10 to about 18.

[0025] In one embodiment, the LEV zeolite has an SAR of about 10 to about 15.

[0026] In one embodiment, the Cu component is present in an amount greater than about 5 wt. % calculated as CuO.

[0027] In one embodiment, the Cu component is present in an amount of about 4.0 wt. % to about 8.0 wt. % calculated as CuO.

[0028] In one embodiment, the LEV zeolite includes a Cu to Al ratio of about 0.30 to about 0.60.

[0029] In one embodiment, the LEV zeolite includes a Cu to Al ratio of about 0.35 to about 0.50.

[0030] In one embodiment, the LEV zeolite includes a Cu to Al ratio greater than about 0.40.

[0031] In one embodiment, an exhaust stream treatment system includes the SCR catalyst of any one of the above embodiments, wherein the selective catalytic reduction catalyst is in one or more of a close-coupled component or an underfloor component.

[0032] In one embodiment, an integrated catalyst system includes the AMOx catalyst of any one of the above embodiments; and, a selective catalytic reduction (SCR) catalyst, wherein the SCR catalyst is located in a zone upstream of the AMOx catalyst, located in a layer above the AMOx catalyst, homogeneously blended with the AMOx catalyst, or any combination thereof.

[0033] In one embodiment, an exhaust treatment system includes the integrated catalyst system of any one of the above embodiments; and, one or more of an oxidation catalyst, a second selective catalytic reduction (SCR) catalyst, and a lean NOx trap (LNT).3ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WOBRIEF DESCRIPTION OF DRAWINGS

[0034] FIG. 1 depicts a diagram of an illustrative exhaust stream treatment system in accordance with an embodiment.

[0035] FIG. 2 depicts a flow diagram of a method of removing nitrogen oxides from an exhaust stream in accordance with an embodiment.

[0036] FIGS. 3-8D each depict a graphical representation of the NOx conversion results of SCR catalysts in accordance with several embodiments.DEFINITIONS

[0037] As used herein, the term “about” when immediately preceding a numerical value means a range of plus or minus 10% of that value, for example, “about 50” means 45 to 55, “about 25,000” means 22,500 to 27,500, etc., unless the context of the disclosure indicates otherwise, or is inconsistent with such an interpretation.

[0038] The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0039] As used in this document, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Nothing in this disclosure is to be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention. As used in this document, the term “comprising” means “including, but not limited to.”

[0040] As used herein, the term “deNOx capability” means the ability of a catalyst to remove NOx from an exhaust stream. For example, a measurement of deNOx capability may comprise the NOx conversion percentage of a catalyst.4ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO

[0041] As used herein, the term “calculated as CuO” means that the weight percent of a Cu component is calculated using the weight of CuO having the same amount of Cu. For example, the weight percent of a 10g Cu component calculated as CuO is calculated using a theoretical CuO weight of 12.518g.

[0042] As used herein, the term “calculated as Fe2O3” means that the weight percent of a Fe component is calculated using the weight of Fe20s having the same amount of Fe. For example, the weight percent of a 10g Fe component calculated as Fe20s is calculated using a theoretical Fe20s weight of 14.298g.

[0043] While various compositions, methods, and devices are described in terms of "comprising" various components or steps (interpreted as meaning "including, but not limited to"), the compositions, methods, and devices can also "consist essentially of' or "consist of' the various components and steps, and such terminology should be interpreted as defining essentially closed-member groups.

[0044] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity.

[0045] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (for example, bodies of the appended claims) are generally intended as “open” terms (for example, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those skilled in the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (for example, “a” and / or “an” should be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that5ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO such recitation should be interpreted to mean at least the recited number (for example, the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “ a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “ a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

[0046] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0047] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 compounds. Similarly, a group having 1-5 compounds refers to groups having 1, 2, 3, 4, or 5 compounds, and so forth.6ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WODETAILED DESCRIPTION

[0048] This disclosure is not limited to the particular systems, devices and methods described, as these may vary. The terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope.

[0049] Catalysts

[0050] Catalysts may be assembled for selective catalytic reduction. The catalysts may comprise zeolite compositions comprising a silica-to-alumina ratio (SAR) between about 8 and about 20. In some embodiments, the zeolite compositions comprise an LEV zeolite. In some embodiments, the zeolite compositions comprise a Cu component. In some embodiments, the zeolite composition has a Cu component of about 4.0 wt. % to about 8.0 wt. % calculated as CuO. The LEV zeolites provide reduced N2O formation, sulfur recovery, and increased deNOx capacity as compared to some of the preferred zeolite frameworks with higher SARs and lower Cu components.

[0051] The zeolite composition may comprise an LEV zeolite. The LEV zeolite may comprise any SAR value effective for the removal of nitrogen oxide from a gaseous stream. In some embodiments, the LEV zeolite has a SAR ratio of about 8.0, about 8.1, about 8.2, about 8.3, about 8.4, about 8.5, about 8.6, about 8.7, about 8.8, about 8.9, about 9.0, about 9.1, about 9.2, about 9.3, about 9.4, about 9.5, about 9.6, about 9.7, about 9.8, about 9.9, about 10.0, about10.1, about 10.2, about 10.3, about 10.4, about 10.5, about 10.6, about 10.7, about 10.8, about10.9, about 11.0, about 11.1, about 11.2, about 11.3, about 11.4, about 11.5, about 11.6, about11.7, about 11.8, about 11.9, about 12.0, about 12.1, about 12.2, about 12.3, about 12.4, about12.5, about 12.6, about 12.7, about 12.8, about 12.9, about 13.0, about 13.1 about 13.2, about13.3 about 13.4, about 13.5, about 13.6, about 13.7, about 13.8, about 13.9, about 14.0, about14.1, about 14.2, about 14.3, about 14.4, about 14.5, about 14.6, about 14.7, about 14.8, about14.9, about 15.0, about 15.1, about 15.2, about 15.3, about 15.4, about 15.5, about 15.6, about15.7, about 15.8, about 15.9, about 16.0, about 16.1, about 16.2, about 16.3, about 16.4, about16.5, about 16.6, about 16.7, about 16.8, about 16.9, about 17.0, about 17.1, about 17.2, about17.3, about 17.4, about 17.5, about 17.6, about 17.7, about 17.8, about 17.9, about 18.0, about18.1, about 18.2, about 18.3, about 18.4, about 18.5, about 18.6, about 18.7, about 18.8, about18.9, about 19.0, about 19.1, about 19.2, about 19.3, about 19.4, about 19.5, about 19.6, about19.7, about 19.8, about 19.9, about 20.0, or any value range of values between any two of these values. In some embodiments, the LEV zeolite has an SAR ratio of about 8.0 to about 20.0, about 10.0 to about 18.0, about 10.0 to about 15.0, or about 12.0 to about 16.0.7ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO

[0052] In some embodiments, the LEV zeolite comprises a Cu component. The Cu component may be present in the LEV zeolite in any amount effective for the removal of nitrogen oxide from a gaseous stream. In some embodiments, the Cu component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of about 2.0 wt. %, about 2.1 wt. %, about 2.2 wt. %, about 2.3 wt. %, about 2.4 wt. %, about 2.5 wt. %, about 2.6 wt. %, about 2.7 wt. %, about 2.8 wt. %, about 2.9 wt. %, about 3.0 wt. %, about 3.1 wt. %, about 3.2 wt. %, about 3.3 wt. %, about 3.4 wt. %, about 3.5 wt. %, about 3.6 wt. %, about 3.7 wt. %, about 3.8 wt. %, about 3.9 wt. %, about 4.0 wt. %, about 4.1 wt. %, about 4.2 wt. %, about 4.3 wt. %, about 4.4 wt. %, about 4.5 wt. %, about 4.6 wt. %, about 4.7 wt. %, about 4.8 wt. %, about 4.9 wt. %, about 5.0 wt. %, about 5.1 wt. %, about 5.2 wt. %, about 5.3 wt. %, about 5.4 wt. %, about 5.5 wt. %, about 5.6 wt. %, about 5.7 wt. %, about 5.8 wt. %, about 5.9 wt. %, about 6.0 wt. %, about 6.1 wt. %, about 6.2 wt. %, about 6.3 wt. %, about 6.4 wt. %, about 6.5 wt. %, about 6.6 wt. %, about 6.7 wt. %, about 6.8 wt. %, about 6.9 wt. %, about 7.0 wt. %, about 7.1 wt. %, about 7.2 wt. %, about 7.3 wt. %, about 7.4 wt. %, about 7.5 wt. %, about 7.6 wt. %, about 7.7 wt. %, about 7.8 wt. %, about 7.9 wt. %, about 8.0 wt. % calculated as CuO, or any value range of values between any two of these values. In some embodiments, the Cu component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of about 2.0 wt. % to about 8.0 wt. %, about 4.0 wt. % to about 8.0 wt. %, or about 5.0 wt. % to about 7.0 wt. % calculated as CuO. In some embodiments, the Cu component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of greater than about 4.0 wt. %, greater than about 5.0 wt. %, greater than about 6.0 wt. %, greater than about 6.25 wt. %, or greater than about 7.0 wt. % calculated as CuO.

[0053] The LEV zeolite may comprise any Cu to Al ratio effective for the removal of nitrogen oxide from a gaseous stream. In some embodiments, the LEV zeolite comprises a Cu to Al ratio of about 0.25, about 0.26, about 0.27, about 0.28, about 0.29, about 0.30, about 0.31, about 0.32, about 0.33, about 0.34, about 0.35, about 0.36, about 0.37, about 0.38, about 0.39, about0.40, about 0.41, about 0.42, about 0.43, about 0.44, about 0.45, about 0.46, about 0.47, about0.48, about 0.49, about 0.50, about 0.51, about 0.52, about 0.53, about 0.54, about 0.55, about0.56, about 0.57, about 0.58, about 0.59, about 0.60, or any value range of values between any two of these values. In some embodiments, the LEV zeolite comprises a Cu to Al ratio of about 0.30 to about 0.60 or about 0.35 to about 0.50.

[0054] In some embodiments, the LEV zeolite further comprises a secondary component. In some embodiments, the secondary component comprises one or more of Fe, Ce, Mn, and Zn.8ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WOThe secondary component may be present in the LEV zeolite in any amount effective for the removal of nitrogen oxide from a gaseous stream. In some embodiments, the secondary component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of about 2.0 wt. %, about 2.1 wt. %, about 2.2 wt. %, about 2.3 wt. %, about 2.4 wt. %, about 2.5 wt. %, about 2.6 wt. %, about 2.7 wt. %, about 2.8 wt. %, about 2.9 wt. %, about 3.0 wt. %, about 3.1 wt. %, about 3.2 wt. %, about 3.3 wt. %, about 3.4 wt. %, about 3.5 wt. %, about 3.6 wt. %, about 3.7 wt. %, about 3.8 wt. %, about 3.9 wt. %, about 4.0 wt. %, about 4.1 wt. %, about 4.2 wt. %, about 4.3 wt. %, about 4.4 wt. %, about 4.5 wt. %, about 4.6 wt. %, about 4.7 wt. %, about 4.8 wt. %, about 4.9 wt. %, about 5.0 wt. %, about 5.1 wt. %, about 5.2 wt. %, about 5.3 wt. %, about 5.4 wt. %, about 5.5 wt. %, about 5.6 wt. %, about 5.7 wt. %, about 5.8 wt. %, about 5.9 wt. %, about 6.0 wt. %, about 6.1 wt. %, about 6.2 wt. %, about 6.3 wt. %, about 6.4 wt. %, about 6.5 wt. %, about 6.6 wt. %, about 6.7 wt. %, about 6.8 wt. %, about 6.9 wt. %, about 7.0 wt. %, about 7.1 wt. %, about 7.2 wt. %, about 7.3 wt. %, about 7.4 wt. %, about 7.5 wt. %, about 7.6 wt. %, about 7.7 wt. %, about 7.8 wt. %, about 7.9 wt. %, about 8.0 wt. % calculated as an oxide of the secondary component, or any value range of values between any two of these values. In some embodiments, the secondary component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of about 2.0 wt. % to about 8.0 wt. %, about 4.0 wt. % to about 8.0 wt. %, or about 5.0 wt. % to about 7.0 wt. % calculated as an oxide of the secondary component. In some embodiments, the secondary component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of greater than about 4.0 wt. %, greater than about 5.0 wt. %, greater than about 6.0 wt. %, greater than about 6.25 wt. %, or greater than about 7.0 wt. % calculated as an oxide of the secondary component.

[0055] In some embodiments, the LEV zeolite further comprises an Fe component. The Fe component may be present in the LEV zeolite in any amount effective for the removal of nitrogen oxide from a gaseous stream. In some embodiments, the Fe component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of about 2.0 wt. %, about 2.1 wt. %, about 2.2 wt. %, about 2.3 wt. %, about 2.4 wt. %, about 2.5 wt. %, about 2.6 wt. %, about 2.7 wt. %, about 2.8 wt. %, about 2.9 wt. %, about 3.0 wt. %, about 3.1 wt. %, about 3.2 wt. %, about 3.3 wt. %, about 3.4 wt. %, about 3.5 wt. %, about 3.6 wt. %, about 3.7 wt. %, about 3.8 wt. %, about 3.9 wt. %, about 4.0 wt. %, about 4.1 wt. %, about 4.2 wt. %, about 4.3 wt. %, about 4.4 wt. %, about 4.5 wt. %, about 4.6 wt. %, about 4.7 wt. %, about 4.8 wt. %, about 4.9 wt. %, about 5.0 wt. %, about 5.1 wt. %, about 5.2 wt. %, about 5.3 wt. %, about 5.4 wt. %, about 5.5 wt. %, about 5.6 wt. %, about 5.7 wt. %, about9ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO5.8 wt. %, about 5.9 wt. %, about 6.0 wt. %, about 6.1 wt. %, about 6.2 wt. %, about 6.3 wt. %, about 6.4 wt. %, about 6.5 wt. %, about 6.6 wt. %, about 6.7 wt. %, about 6.8 wt. %, about6.9 wt. %, about 7.0 wt. %, about 7.1 wt. %, about 7.2 wt. %, about 7.3 wt. %, about 7.4 wt. %, about 7.5 wt. %, about 7.6 wt. %, about 7.7 wt. %, about 7.8 wt. %, about 7.9 wt. %, about 8.0 wt. % calculated as Fe2Os, or any value range of values between any two of these values. In some embodiments, the Fe component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of about 2.0 wt. % to about 8.0 wt. %, about 4.0 wt. % to about 8.0 wt. %, or about 5.0 wt. % to about 7.0 wt. % calculated as Fe2Os. In some embodiments, the Fe component is present in the LEV zeolite in an amount with respect to the total mass of the LEV zeolite composition of greater than about 4.0 wt. %, greater than about 5.0 wt. %, greater than about 6.0 wt. %, greater than about 6.25 wt. %, or greater than about 7.0 wt. % calculated as Fe20s.

[0056] Exhaust Treatment Systems

[0057] Exhaust treatment systems may be assembled using the above-described catalysts. FIG. 1 depicts a diagram of an illustrative exhaust stream treatment system. In some embodiments, the system comprises a diesel oxidation catalyst 101 configured to remove hydrocarbons and carbon monoxide from an exhaust stream and a catalyzed soot filter 102 configured to trap solid soot particles. The diesel oxidation catalyst 101 may comprise any diesel oxidation catalyst known to one of ordinary skill in the art. The catalyzed soot filter 102 may comprise any catalyzed soot filter known to one of ordinary skill in the art.

[0058] In some embodiments, the system comprises an SCR catalyst. The SCR catalyst may comprise an LEV zeolite with a composition as-described above. In some embodiments, the system comprises an SCR catalyst in an underfloor position 103. In some embodiments, the SCR catalyst in an underfloor position 103 is positioned downstream from the diesel oxidation catalyst 101 and the catalyzed soot filter 102. In some embodiments, the underfloor position 103 is underneath the main body of a vehicle.

[0059] In some embodiments, the system comprises an SCR catalyst in a close-couple position 104. In some embodiments, the SCR catalyst in a close-couple position 104 is positioned upstream from the diesel oxidation catalyst 101 and the catalyzed soot filter 102. In some embodiments, the close-couple position 104 is positioned adjacent to an engine of a vehicle and is configured to receive an exhaust stream directly from the engine.

[0060] In some embodiments, the system comprises an SCR catalyst coated on a substrate. In some embodiments, the system comprises an SCR catalyst with compositions as-described above coated on one of a ceramic substrate, ceramic filter substrate, or a metallic substrate. In 10ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO some embodiments, the system comprises an SCR catalyst with compositions as-described above formulated as extrudates with binders including, but not limited to, alumina, titania, zirconia, and silica.

[0061] In some embodiments, the engine may comprise an internal combustion engine. The internal combustion engine may use any fuel source effective for a vehicle. In some embodiments, the internal combustion engine may be a flexible fuel engine. In some embodiments, the internal combustion engine may use NH3, H2, compressed natural gas (CNG), liquid hydrocarbon, or oxygenated hydrocarbons as the fuel source. In some embodiments, the oxygenated hydrocarbons may comprise methanol or ethanol.

[0062] In some embodiments, the system comprises an ammonia oxidation (AMOx) catalyst. The AMOx catalyst may comprise an LEV zeolite with a composition as-described above. The AMOx catalyst may be located in any location in the exhaust stream effective for the removal of ammonia from the exhaust stream. For example, the AMOx catalyst may be in a close- coupled position, near the engine’s exhaust manifold. Alternatively, the AMOx catalyst may be located downstream of the selective catalytic reduction (SCR) catalyst in the underfloor position.

[0063] In some embodiments, the system comprises an integrated catalyst system. The integrated catalyst system may comprise an AMOx catalyst and an SCR catalyst. One or more of the SCR catalyst and the AMOx catalyst may comprise an LEV zeolite with a composition as-described above. The SCR catalyst may be located in any position relative to the AMOx catalyst effective for the removal of nitrogen oxides from the exhaust stream. In some embodiments, the SCR catalyst is located in a zone upstream of the AMOx catalyst, located in a layer above the AMOx catalyst, homogeneously blended with the AMOx catalyst, or any combination thereof. In some embodiments, the integrated catalyst system may comprise an oxidation catalyst, a second selective catalytic reduction (SCR) catalyst, and a lean NOx trap (LNT).

[0064] Methods of Use

[0065] Methods can be assembled to remove nitrogen oxide from an exhaust stream using the above-described SCR catalysts.

[0066] FIG. 2 depicts a diagram of a method of removing nitrogen oxide from an exhaust stream comprises providing 201 a catalyst product comprising an LEV zeolite. The LEV zeolite may comprise any composition as described above. In some embodiments, the LEV zeolite comprises a SAR between about 8.0 to about 20.0. In some embodiments, the LEV zeolite11ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO comprises a Cu component. In some embodiments, the Cu component is present as compared to the LEV zeolite in an amount of about 4.0 wt. % to about 8.0 wt. % calculated as CuO.

[0067] The method further comprises contacting 202 the catalyst product with an exhaust stream wherein the exhaust stream comprises nitrogen oxide. This allows the catalyst product to remove the nitrogen oxide from the exhaust stream. The exhaust stream may be from any source. In some embodiments, the exhaust stream is from an internal combustion engine.

[0068] In some embodiments, the exhaust stream has a temperature of about 100 °C, about 110 °C, about 120 °C, about 130 °C, about 140 °C, about 150 °C, about 160 °C, about 170 °C, about 180 °C, about 190 °C, about 200 °C, about 210 °C, about 220 °C, about 230 °C, about 240 °C, about 250 °C, about 260 °C, about 270 °C, about 280 °C, about 290 °C, about 300 °C, about 310 °C, about 320 °C, about 330 °C, about 340 °C, about 350 °C, about 360 °C, about 370 °C, about 380 °C, about 390 °C, about 400 °C, about 410 °C, about 420 °C, about 430 °C, about 440 °C, about 450 °C, about 460 °C, about 470 °C, about 480 °C, about 490 °C, about 500 °C, or any value or range of values between any two of these values. In some embodiments, the combustion exhaust stream has a temperature of about 200 °C to about 600 °C, about 250 °C to about 400 °C, or about 300°C to about 350 °C.

[0069] In some embodiments, the exhaust stream further comprises NO2. In some embodiments, the exhaust stream has an NO2 to NOXratio of about 0, about 0.05, about 0.10, about 0.15, about 0.20, about 0.25, about 0.30, about 0.35, about 0.40, about 0.45, about 0.50, about 0.55, about 0.60, about 0.65, about 0.70, about 0.75, about 0.80, about 0.85, about 0.90, about 0.95, about 0.99, about 1.00, or any value or range of values between any two of these values. In some embodiments, the exhaust stream has an NO2 to NOXratio of 0 to less than about 0.99.

[0070] In some embodiments, the SCR catalyst is configured to limit the formation of N2O during the removal of nitrogen oxides from the exhaust stream. In some embodiments, the SCR catalyst is configured to form N2O during the removal of nitrous oxides from the exhaust stream in an amount of less than about 10 ppm, less than about 9 ppm, less than about 8 ppm, less than about 7 ppm, less than about 6 ppm, less than about 5 ppm, less than about 4 ppm, less than about 3 ppm, less than about 2 ppm, less than about 1 ppm, or less than about 0.5 ppm.

[0071] In some embodiments, the exhaust stream comprises NH3 and an inlet NOx concentration. In such an embodiment, contacting 202 the exhaust stream with the SCR catalyst may result in producing a purified gas comprising an outlet NO concentration and an outlet N2O concentration. In such an embodiment, the ratio of the inlet NO concentration to the outlet N2O concentration may be greater than about 60, greater than about 65, greater than about 70, 12ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO greater than about 75, greater than about 80, greater than about 85, greater than about 90, greater than about 95, greater than about 100, greater than about 105, greater than about 110, greater than about 115, greater than about 120, or any value or range of values between any two of these values.EXAMPLES

[0072] Example 1 : LEV Zeolite Synthesis

[0073] LEV zeolites with SAR values of 12, 15, 16, and 20 as measured by inductively coupled plasma optical emission spectroscopy (ICP-OES) were procured from China Catalyst Holding Group, Dalian, China. The H-form zeolite powder as obtained was impregnated with an aqueous copper (II) nitrate solution by incipient wetness impregnation and maintained at 50 °C for 20 hours in a sealed container. The obtained solid was dried and calcined in air in a furnace at 450 °C for 5 hours, to obtain a Cu-loaded zeolite. Three Cu loadings were added to samples of each SAR value resulting in Cu to Al ratios of 0.32, 0.37, and 0.42 for each sample. For the LEV zeolite samples with an SAR of 12, this corresponded to a Cu component of 5.9 wt. %, 6.8 wt. %, and 7.7 wt. % calculated as CuO. For the LEV zeolite samples with an SAR of 15, this corresponded to a Cu component of 5.1 wt. %, 5.9 wt. %, and 6.7 wt. % calculated as CuO. For the LEV zeolite samples with an SAR of 16, this corresponded to a Cu component of 4.0 wt. %, 5.4 wt. %, and 6.1 wt. % calculated as CuO. For the LEV zeolite samples with an SAR of 20, this corresponded to a Cu component of 3.9 wt. %, 4.5 wt. %, and 5.5 wt. calculated as CuO.

[0074] The deNOx performances of the Cu-LEV zeolites were compared against reference Cu- CHA (3.5 wt. % calculated as CuO) and Fe-CHA (2.3 wt. % calculated as Fe20s) obtained using procedures described in WIPO Patent Application Number WO2013182974A1 and U.S. Patent No. US9011807B2, respectively.

[0075] Example 2: Standard SCR deNOx Performance against Cu-CHA zeolites

[0076] To test the SCR performance of the zeolite materials, the Cu-or Fe-loaded zeolite materials were prepared in a slurry with an aqueous solution of Zr-acetate. The slurry was dried at ambient temperature in air under stirring and calcined at 550 °C for 1 hour. This produced a product with a binder component of 5 wt. % ZrO? based on the total amount of the product. The product was crushed and the particles with a diameter of 250 microns to 500 microns were used as samples for the test. A portion of the obtained powder was aged at one of 550 °C or 650 °C for 50 hours in a flow of 10 vol. % steam in air to provide aged samples.13ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO

[0077] The selective catalytic reduction (SCR) test was carried out in a fixed-bed reactor with loading of 120 mg of the test sample and corundum of the same sieve fraction as a diluent to about a 1 mL bed volume, in accordance with following conditions:

[0078] Gas feed: 500 vppm NOX(NOX= NO + NO2), 500 vppm NH3, 5 vol. % H2O, 10 vol. % O2and a balance of N2, with a gas hourly space velocity (GHSV) of 80,000 h’1;

[0079] Temperature: RUN1 : 200 °C, 400 °C, 575 °C (first run for degreening) RUN2: 175 °C, 200 °C, 225 °C, 250 °C, 350 °C, 450 °C, 550 °C, 575 °C.

[0080] Gas feed with various N02 / N0xratios were used (=0, 0.25, 0.5).

[0081] NOx conversions as measured from RUN 2 at 200 °C and 550 °C are reported as the test results. Results of the NOx conversion testing at 200 °C are provided in FIG. 3 and results of the N2O formation testing are provided in FIG. 4 for samples aged after 650°C for 50h. It was confirmed that the LEV zeolite with an SAR of 15 and a Cu loading of 6.7 wt. % had a comparable low temperature deNOx performance with the reference Cu-CHA. Despite having lower pore dimensionality (LEV: 2D; CHA: 3D), the use of the low SAR framework with sufficient Cu provided comparable activities to the reference Cu-CHA sample. Furthermore, it was identified that the N2O formation in the LEV zeolite samples were lower compared to the reference Cu-CHA sample tested under the same conditions. The data shows that low N2O formation can be accomplished simultaneously with high NOx conversions when using a sufficiently low SAR LEV.

[0082] Additional testing was performed on the NOx conversion percentage of the zeolites at 550 °C. The results of the high temperature deNOx performances of the zeolites aged at 650°C for 50 h are shown in FIG. 5. The results show that Cu-containing LEV zeolite samples have high temperature deNOx performances that are at least comparable to the reference Cu-CHA zeolites.

[0083] Example 3: Sulfurization-desulfurization (SOx-deSOx) Treatments

[0084] The deNOx performances of the Cu-LEV zeolites after sulfurization and desulfurization (SOx-deSOx) treatments were compared against the reference Cu-CHA zeolite. For SOx treatment, catalyst after aging at 650 °C / 50h was exposed to gas feed with the following composition at 400°C for 96 h. The net exposure of S corresponded to 23.6 wt. / wt.% relative to the weight of the catalyst.

[0085] Gas feed for SOx treatment comprised GHSV 10000 h’1, 35ppm SO2, 8% H2O, 7%CO2, 10% O2, balance N2

[0086] For deSOx treatment, catalyst after SOx treatment was exposed to gas feed with the following composition at 550°C for 0.5 hours.14ACTIVE\1624169278.1230013 WOO 1 ZECM-23 - 1370WO

[0087] Gas feed for deSOx treatment comprised GHSV 20000 h’1, 8% H2O, 7%CO2, 10% O2, balance N2.

[0088] NOx conversion results at 200°C are provided in FIG. 6. With the LEV zeolites after the aging in Example 2, the absolute NOx conversion after SOx-deSOx treatment was around 55%, thus about 75% of the original conversion was retained. The red line 601 indicates the low temperature deNOx performance of Cu-LEV with SAR 15 and 6.7 wt. % Cu after SOx- deSOx treatment, with this LEV material having the best performance among the LEV samples tested. From comparison, the reference Cu-CHA after the aging in Example 2 had a significantly lower NOx conversion percentage of 25% after SOx-deSOx treatment. The current results show the high sulfur stability of LEV zeolites against SOx-deSOx treatment.

[0089] Example 4: Comparison with Fe containing zeolites for SCR in the presence and absence of NO2 species

[0090] The deNOx performances of Cu-LEV zeolites in the presence and absence of NO2 species was compared against reference Cu-CHA and Fe-CHA zeolites. The catalysts were either tested both in a fresh state and after aging at 550°C for 50 hours. Three testing conditions were used: standard SCR (NO2 / NOX = 0), fast SCR (NO2 / NOX = 0.5) and intermediate (NO2 / NOX = 0.25) conditions. Testing was performed on the NOx conversion percentage of the zeolites at 200 °C on the fresh samples and the aged samples, with results provided in FIGS. 7A and 7C, respectively. Comparison was performed on the N2O formation of the zeolites in ppm at 200 °C on the fresh samples and the aged samples, with results provided in FIGS. 7B and 7D, respectively. Testing was performed on the NOx conversion percentage of the zeolites at 300 °C on the fresh samples and the aged samples, with results provided in FIGS. 8 A and 8C, respectively. Testing was performed on the N2O formation of the zeolites in ppm at 300 °C on the fresh samples and the aged samples, with results provided in FIGS. 8B and 8D, respectively.

[0091] The reference Cu-CHA catalyst showed higher NOx conversion under standard SCR conditions, however the N2O make was significantly higher than that of the reference Fe-CHA, especially when more NO2 was present in the feed. Cu-LEV showed improved NOx conversion performance under conditions with NO2 / NOX = 0 and 0.5 as compared to the Fe-CHA references while making similarly low levels of N2O. For NO2 / NOX = 0.25, Cu-LEV and Fe- CHA reference show similar NOx conversion while Cu-LEV has the lowest N2O formation. This shows the Cu-LEV zeolites have both high deNOx performances and low N2O yields as compared to Fe zeolites.15ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO

[0092] Various of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.16ACTIVEU624169278.1

Claims

230013 WOO 1 ZECM-23 - 1370WOClaims1. A selective catalytic reduction (SCR) catalyst for the abatement of nitrogen oxides (NOx) in an exhaust gas stream comprising: an LEV zeolite comprising a silica-to-alumina ratio (SAR) between about 8 and about 20 and a Cu component, wherein the Cu component is present in an amount of about 2.0 wt. % to about 8.0 wt. % calculated as CuO.

2. The SCR catalyst of claim 1, wherein the LEV zeolite has an SAR of about 10 to about 18.

3. The SCR catalyst of claim 1, wherein the LEV zeolite has an SAR of about 10 to about 15.

4. The SCR catalyst of claim 1, wherein the Cu component is present in an amount of about 4.0 wt. % to about 8.0 wt. % calculated as CuO.

5. The SCR catalyst of claim 1, wherein the LEV zeolite comprises a Cu to Al ratio of about 0.30 to about 0.60.

6. The SCR catalyst of claim 1, wherein the LEV zeolite comprises a secondary component including one or more of Fe, Ce, Mn, and Zn.

7. A method of removing nitrogen oxides (NOx) from an exhaust stream, the method comprising: providing the SCR catalyst of any one of claims 1 to 6; and contacting the SCR catalyst with an exhaust stream wherein the exhaust stream comprises NOx.

8. The method of claim 7, wherein the exhaust stream is from an internal combustion engine.

9. The method of claim 8, wherein a fuel used in the internal combustion engine comprises liquid hydrocarbon, oxygenated hydrocarbon, compressed natural gas, NH3 or H2.

10. A method for reducing NOx emissions in an exhaust gas comprising: providing the SCR catalyst of any one of claims 1 to 6; contacting an exhaust gas comprising NH3 and an inlet NO concentration with the SCR catalyst; and17ACTIVEU624169278.1230013 WOO 1 ZECM-23 - 1370WO producing a purified gas containing an outlet NO concentration and an outlet N2O concentration, wherein the ratio of the inlet NO concentration to the outlet N2O concentration is greater than about 60.

11. The method of claim 10, wherein the ratio of the inlet NO concentration to the outlet N2O concentration is greater than about 90.

12. The method of claim 10, wherein the ratio of the inlet NO concentration to the outlet N2O concentration is greater than about 120.

13. An ammonia oxidation (AMOx) catalyst comprising: an LEV zeolite comprising a silica-to-alumina ratio (SAR) between about 8 and about 20 and a Cu component, wherein the Cu component is present in an amount of about 2.0 wt. % to about 8.0 wt. % calculated as CuO.

14. The AMOx catalyst of claim 13, wherein the LEV zeolite has an SAR of about 10 to about 18.

15. The AMOx catalyst of claim 13, wherein the Cu component is present in an amount greater than about 5 wt. % calculated as CuO.

16. An exhaust stream treatment system comprising: the SCR catalyst of any one of claims 1 to 6, wherein the selective catalytic reduction catalyst is in one or more of a close- coupled component or an underfloor component.

17. An integrated catalyst system comprising: the AMOx catalyst of any one of claims 13 to 15; and, a selective catalytic reduction (SCR) catalyst, wherein the SCR catalyst is located in a zone upstream of the AMOx catalyst, located in a layer above the AMOx catalyst, homogeneously blended with the AMOx catalyst, or any combination thereof.

18. An exhaust treatment system comprising: the integrated catalyst system of claim 17; and, one or more of an oxidation catalyst, a second selective catalytic reduction (SCR) catalyst, and a lean NOx trap (LNT).18ACTIVEU624169278.1

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