SCR Zeolite Catalysts for Improved NOx Reduction

Abstract

The present invention discloses a crystalline aluminosilicate small-pore zeolite having a maximum ring size of eight tetrahedral atoms, wherein the zeolite comprises copper, wherein the Cu: Al atomic ratio is between 0.12 and 0.55; and manganese, wherein the Mn: Cu atomic ratio is between 0.05 and 0.95; and a metal M, wherein M is selected from magnesium, calcium, barium, strontium, yttrium, titanium, zirconium, niobium, iron, zinc, silver, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and mixtures thereof, and wherein the M: Cu atomic ratio is between 0.05 and 0.80; and wherein the sum of the atomic ratios of copper, manganese and the metal M to aluminum, (Cu+Mn+M): Al, is between 0.20 and 0.80; and wherein the zeolite comprises at least 2.5 wt.-% of copper, calculated as CuO and based on the total weight of the zeolite. Catalyst substrate monoliths comprising the crystalline aluminosilicate zeolite are also disclosed. These catalyst substrate monoliths can be used in a process for the removal of nitrogen oxides from combustion exhaust gases, and they can be part of emissions treatment systems.

Claims

1. A crystalline aluminosilicate small-pore zeolite having a maximum ring size of eight tetrahedral atoms, wherein the zeolite comprises copper, wherein the Cu: Al atomic ratio is between 0.12 and 0.55; and manganese, wherein the Mn: Cu atomic ratio is between 0.05 and 0.95; and a metal M, wherein M is selected from magnesium, calcium, barium, strontium, yttrium, titanium, zirconium, niobium, iron, zinc, silver, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and mixtures thereof, and wherein the M: Cu atomic ratio is between 0.05 and 0.80; and wherein the sum of the atomic ratios of copper, manganese and the metal M to aluminum, (Cu+Mn+M): Al, is between 0.20 and 0.80; and wherein the zeolite comprises at least 2.5 wt.-% of copper, calculated as CuO and based on the total weight of the zeolite.

2. The crystalline aluminosilicate small-pore zeolite having a maximum ring size of eight tetrahedral atoms according to claim 1, wherein the zeolite is selected from ACO, AEI, AEN, AFN, AFT, AFX, ANA, APC, APD, ATT, BIK, CDO, CHA, DDR, DFT, EAB, EDI, EPI, ERI, ESV, ETL, GIS, GOO, IHW, ITE, ITW, LEV, KFI, MER, MON, NSI, OWE, PAU, PHI, RHO, RTH, SAT, SAV, SIV, THO, TSC, UEI, UFI, VNI, YUG, ZON, and mixtures and intergrowths thereof.

3. The crystalline aluminosilicate small-pore zeolite having a maximum ring size of eight tetrahedral atoms according to claim 1, wherein the zeolite is selected from AEI, CHA, AFX, and LEV.

4. The crystalline aluminosilicate small-pore zeolite according to claim 1, wherein the zeolite has a SAR value of 5 to 50.

5. The crystalline aluminosilicate small-pore zeolite according to claim 1, wherein the metal M is selected from magnesium, calcium, strontium, barium, iron, yttrium, zirconium, cerium, praseodymium, samarium and mixtures thereof.

6. A process for the removal of NO.sub.x from combustion exhaust gases, wherein a crystalline aluminosilicate zeolite according to claim 1 is used as the SCR catalytically active composition for the conversion of NO.sub.x.

7. A catalysed substrate monolith comprising an SCR catalytically active composition for the conversion of NO.sub.x for use in treating automotive combustion exhaust gases, wherein said SCR catalytically active composition for the conversion of NO.sub.x is a crystalline aluminosilicate zeolite according to claim 1.

8. The catalysed substrate monolith according to claim 7, wherein the crystalline aluminosilicate zeolite according to is present in the form of a washcoat on a carrier substrate.

9. The catalysed substrate monolith according to claim 8, wherein the carrier substrate is a honeycomb flow-through substrate, a honeycomb wall-flow filter, a corrugated substrate, a wound or packed fiber filter, an open cell foam, or a sintered metal filter.

10. The catalysed substrate monolith according to claim 7, wherein the catalysed substrate monolith is an extruded catalysed substrate monolith.

11. The catalysed substrate monolith according to claim 9, wherein the monolith is a flow-through monolith coated with a bottom layer comprising an oxidation catalyst and a top layer comprising the crystalline aluminosilicate zeolite.

12. An emissions treatment system for the removal of NO.sub.x emissions from exhaust gases of internal combustion engines, and optionally also for the removal of particulate matter, the system comprising, in the following order, from upstream to downstream: a) means for injecting ammonia or an ammonia precursor solution into the exhaust gas stream, b) a catalysed substrate monolith comprising an SCR-catalytically active composition for the conversion of NO.sub.x in automotive combustion exhaust gases, wherein said SCR catalytically active compositions for the conversion of NO.sub.x is a crystalline aluminosilicate zeolite according to claim 1, and wherein the substrate monolith is selected from honeycomb flow-through substrates, honeycomb wall-flow filters, corrugated substrates, wound or packed fiber filters, open cell foams, sintered metal filters, and extruded catalysed substrate monoliths.

13. The emissions treatment system according to claim 12, wherein said emissions treatment system is arranged in a close-coupled position.

14. The emissions treatment system according to claim 12, wherein said emissions treatment system is arranged in an underfloor position.

15. A method for the removal of NOx emissions from exhaust gases of internal combustion engines, and optionally also for the removal of particulate matter, the method comprising, in the following order, from upstream to downstream: a) injecting ammonia or an ammonia precursor solution into the exhaust gas stream, b) introducing the exhaust gas from step a) into a catalysed substrate monolith comprising an SCR-catalytically active composition for the conversion of NOx in automotive combustion exhaust gases, wherein said SCR catalytically active compositions for the conversion of NO.sub.x is a crystalline aluminosilicate zeolite according to claim 1, and wherein the substrate monolith is selected from honeycomb flow-through substrates, honeycomb wall-flow filters, corrugated substrates, wound or packed fiber filters, open cell foams, sintered metal filters, and extruded catalysed substrate monoliths.

16. The method according to claim 15, wherein the internal combustion engine is selected from gasoline, diesel, and hydrogen internal combustion engines (H.sub.2 ICE).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0147] FIG. 1 shows the NO.sub.x conversion and the N.sub.2O reduction, each in percent, for CE1, CE6, CE9, Ex1, Ex2, Ex3 and Ex4 in the fresh and aged state at 175 C. and 300 C. under NO only conditions.

[0148] FIG. 2 shows the NO.sub.x conversion and the N.sub.2O reduction, each in percent, for CE1, Ex1, Ex2, Ex3, and Ex4 in the fresh and aged state at 175 C. and 300 C. under 25% NO.sub.2 conditions.

[0149] FIG. 3 shows the NO.sub.x conversion and the N.sub.2O reduction, each in percent, for CE11, CE12, Ex17, Ex18, Ex19 and Ex20 at 175% under NO only and 25% NO.sub.2 conditions.

EMBODIMENTS

Comparative Example 1 (CE1): CuCHA

[0150] 11.5 g of copper (II) acetylacetonate (24.4% by weight Cu, ex Aldrich) was coarsely mixed with 96.5 g of CHA (SAR 13.4) in a sealable plastic bottle of 250 ml capacity. Next 10 g Y-stabilised ZrO.sub.2 beads, (5 mm diameter), were added. The bottle was sealed and locked into a paint shaker (Olbrich Model RM 500, 0.55 KW) and homogenised by vibration for 5 minutes. The bottle was then unlocked from the paint shaker and the mixture passed through a coarse sieve to remove the beads. Finally the mixed powders were transferred to a calcination vessel and heated in static air to 600 C. (at a ramp rate of 5 C./min) and for a period of 2 hours.

[0151] The CHA thus obtained had a Cu: Al molar ratio of 0.21 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 2 (CE2): CuCHA

[0152] 16.1 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O crystals were dissolved under stirring in 40 g of de-ionised water. The solution thus produced was added dropwise to 94.5 g of CHA (SAR 13.4) with constant stirring over 15 minutes. The powder obtained was further dried in air at 80 C. for 4 h following by calcination for 2 hours at 600 C. in air.

[0153] The CHA thus obtained had a Cu: Al molar ratio of 0.33 and a Cu content of 5.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 3 (CE3): CuCHA

[0154] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 23.1 g of copper (II) acetylacetonate and 93.0 g of CHA (SAR 13.4).

[0155] The CHA thus obtained had a Cu: Al molar ratio of 0.43 and a Cu content of 7.0 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 4 (CE4): CuCHA

[0156] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 9.1 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O and 80.0 g of CHA (SAR 21.4).

[0157] The CHA thus obtained had a Cu: Al molar ratio of 0.36 and a Cu content of 4.0 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 5 (CE5): CuAFX

[0158] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate and 96.5 g of AFX (SAR 8.6).

[0159] The AFX thus obtained had a Cu: Al molar ratio of 0.14 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 6 (CE6): CuFeCHA

[0160] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of Copper (II) Acetylacetonate, 15.5 g of Iron (III) Acetylacetonate and 93.0 g of CHA (SAR 13.4).

[0161] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Cu: Fe molar ratio of 1.0, a (Cu+Fe): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 7 (CE7): CuBaCHA

[0162] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 15.5 g of Ba (II) acetylacetonate hydrate and 89.7 g of CHA (SAR 13.4).

[0163] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Cu: Ba molar ratio of 1.0, a (Cu+Ba): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 8 (CE8): CuSmCHA

[0164] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 20.5 g of Sm(II) acetylacetonate and 88.8 g of CHA (SAR 13.4).

[0165] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Cu: Sm molar ratio of 1.0, a (Cu+Sm): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 9 (CE9): CuMnCHA

[0166] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 15.5 g of Mn(III) acetylacetonate and 93.0 g of CHA (SAR 13.4).

[0167] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Cu: Mn molar ratio of 1.0, a (Cu+Mn): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 10 (CE10): CuAEI

[0168] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate and 96.5 g of AEI (SAR 16).

[0169] The AEI thus obtained had a Cu: Al molar ratio of 0.24 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 11 (CE11): CuMnKCHA

[0170] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 9.1 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 2.3 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %), 0.6 g of KNO.sub.3 and 96.2 g of CHA (SAR 13.4).

[0171] The CHA thus obtained had a Cu: Al molar ratio of 0.18, a Mn: Al molar ratio of 0.03, a (Cu+Mn): K molar ratio of 7, and a Cu content of 3.0 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Comparative Example 12 (CE1): CuMnNaCHA

[0172] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 9.1 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 2.3 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %), 0.5 g of NaNO.sub.3 and 96.2 g of CHA (SAR 13.4).

[0173] The CHA thus obtained had a Cu: Al molar ratio of 0.18, a Mn: Al molar ratio of 0.03, a (Cu+Mn): Na molar ratio of 7, and a Cu content of 3.0 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 1 (Ex1): CuMnFeCHA

[0174] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 10.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 5.3 g of Fe(NO.sub.3).sub.3.Math.9H.sub.2O, 6.3 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 94.3 g of CHA (SAR 13.4).

[0175] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.38, a Fe: Cu molar ratio of 0.38, a (Cu+Mn+Fe): Al molar ratio of 0.35 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 2 (Ex2): CuMnFeCHA

[0176] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 10.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 8.8 g of Fe(NO.sub.3).sub.3.Math.9H.sub.2O, 10.5 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 93.2 g of CHA (SAR 13.4).

[0177] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.65, a Fe: Cu molar ratio of 0.50, a (Cu+Mn+Fe): Al molar ratio of 0.45 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 3 (Ex3): CuMnFeCHA

[0178] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 7.7 g of Mn(III) acetylacetonate, 7.7 g of iron (III) acetylacetonate, and 93.0 g of CHA (SAR 13.4).

[0179] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.50, a Fe: Cu molar ratio of 0.50, a (Cu+Mn+Fe): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 4 (Ex4): CuMnFeCHA

[0180] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 10.8 g of Mn(III) acetylacetonate, 4.6 g of iron (III) acetylacetonate, and 93.0 g of CHA (SAR 13.4).

[0181] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Fe: Cu molar ratio of 0.30, a (Cu+Mn+Fe): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 5 (Ex5): CuMnFeCHA

[0182] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 4.6 g of Mn(III) acetylacetonate, 10.8 g of Iron (III) acetylacetonate, and 93.0 g of CHA (SAR 13.4).

[0183] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.30, a Fe: Cu molar ratio of 0.70, a (Cu+Mn+Fe): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 6 (Ex6): CuMnFeCHA

[0184] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 19.2 g of copper (II) acetylacetonate, 7.7 g of Mn(III) acetylacetonate, 7.7 g of iron (III) acetylacetonate, and 94.8 g of CHA (SAR 13.4).

[0185] The CHA thus obtained had a Cu: Al molar ratio of 0.33, a Mn: Cu molar ratio of 0.30, a Fe: Cu molar ratio of 0.30, a (Cu+Mn+Fe): Al molar ratio of 0.53 and a Cu content of 5.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 7 (Ex7): CuMnFeCHA

[0186] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 19.2 g of copper (II) acetylacetonate, 4.6 g of Mn(III) acetylacetonate, 4.6 g of iron (III) acetylacetonate, and 96.1 g of CHA (SAR 13.4).

[0187] The CHA thus obtained had a Cu: Al molar ratio of 0.33, a Mn: Cu molar ratio of 0.18, a Fe: Cu molar ratio of 0.18, a (Cu+Mn+Fe): Al molar ratio of 0.45 and a Cu content of 5.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 8 (Ex8): CuMnFeCHA

[0188] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 4.6 g of Mn(III) acetylacetonate, 4.6 g of iron (III) acetylacetonate, and 94.4 g of CHA (SAR 21.4).

[0189] The CHA thus obtained had a Cu: Al molar ratio of 0.32, a Mn: Cu molar ratio of 0.30, a Fe: Cu molar ratio of 0.30, a (Cu+Mn+Fe): Al molar ratio of 0.51 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 9 (Ex9): CuMnFeAFX

[0190] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 4.6 g of Mn(III) acetylacetonate, 4.6 g of iron (III) acetylacetonate, and 94.4 g of AFX (SAR 8.6).

[0191] The AFX thus obtained had a Cu: Al molar ratio of 0.14, a Mn: Cu molar ratio of 0.30, a Fe: Cu molar ratio of 0.30, a (Cu+Mn+Fe): Al molar ratio of 0.22 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 10 (Ex10): CuMnSmCHA

[0192] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 10.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 5.8 g of Sm(NO.sub.3).sub.3.Math.6H.sub.2O, 6.3 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 93.2 g of CHA (SAR 13.4).

[0193] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.38, a Sm: Cu molar ratio of 0.30, a (Cu+Mn+Sm): Al molar ratio of 0.35 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 11 (Ex11): CuMnSmCHA

[0194] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 10.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 9.8 g of Sm(NO.sub.3).sub.3.Math.6H.sub.2O, 10.5 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 91.1 g of CHA (SAR 13.4).

[0195] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.65, a Sm: Cu molar ratio of 0.50, a (Cu+Mn+Sm): Al molar ratio of 0.45 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 12 (Ex12): CuMnSmCHA

[0196] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 7.7 g of Mn(III) acetylacetonate, 10.2 g of Sm(III) acetylacetonate, and 90.9 g of CHA (SAR 13.4).

[0197] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.50, a Sm: Cu molar ratio of 0.50, a (Cu+Mn+Sm): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 13 (Ex13): CuMnSmCHA

[0198] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 10.8 g of Mn(III) acetylacetonate, 6.1 g of Sm(III) acetylacetonate, and 91.8 g of CHA (SAR 13.4).

[0199] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Sm: Cu molar ratio of 0.30, a (Cu+Mn+Sm): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 14 (Ex14): CuMnSmCHA

[0200] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 2.3 g of Mn(III) acetylacetonate, 14.3 g of Sm(III) acetylacetonate, and 90.6 g of CHA (SAR 13.4).

[0201] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.15, a Sm: Cu molar ratio of 0.73, a (Cu+Mn+Sm): Al molar ratio of 0.39 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 15 (Ex15): CuMnSmCHA

[0202] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 19.2 g of copper (II) acetylacetonate, 7.7 g of Mn(III) acetylacetonate, 10.2 g of Sm(III) acetylacetonate, and 90.9 g of CHA (SAR 13.4).

[0203] The CHA thus obtained had a Cu: Al molar ratio of 0.33, a Mn: Cu molar ratio of 0.30, a Sm: Cu molar ratio of 0.30, a (Cu+Mn+Sm): Al molar ratio of 0.53 and a Cu content of 5.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 16 (Ex16): CuMnSmCHA

[0204] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 19.2 g of copper (II) acetylacetonate, 4.6 g of Mn(III) acetylacetonate, 6.2 g of Sm(III) acetylacetonate, and 94.9 g of CHA (SAR 13.4).

[0205] The CHA thus obtained had a Cu: Al molar ratio of 0.33, a Mn: Cu molar ratio of 0.18, a Sm: Cu molar ratio of 0.18, a (Cu+Mn+Sm): Al molar ratio of 0.45 and a Cu content of 5.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 17 (Ex17): CuMnBaCHA

[0206] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 4.6 g of Mn(III) acetylacetonate, 4.6 g Ba (II) acetylacetonate hydrate, and 95.2 g of CHA (SAR 13.4).

[0207] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.30, a Ba: Cu molar ratio of 0.30, a (Cu+Mn+Ba): Al molar ratio of 0.34 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 18 (Ex18): CuMnBaCHA

[0208] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 7.7 g of Mn(III) acetylacetonate, 7.7 g Ba (II) acetylacetonate hydrate, and 91.4 g of CHA (SAR 13.4).

[0209] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.50, a Ba: Cu molar ratio of 0.50, a (Cu+Mn+Ba): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 19 (Ex19): CuMnCaCHA

[0210] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 21.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 5.2 g of Ca (NO.sub.3) 2.4H.sub.2O, 5.5 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 93.7 g of CHA (SAR 13.4).

[0211] The CHA thus obtained had a Cu: Al molar ratio of 0.43, a Mn: Cu molar ratio of 0.25, a Ca: Cu molar ratio of 0.25, a (Cu+Mn+Ca): Al molar ratio of 0.65 and a Cu content of 7.0 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 20 (Ex20): CuMnCaCHA

[0212] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 21.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 3.1 g of Ca (NO.sub.3) 2.4H.sub.2O, 3.3 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 94.8 g of CHA (SAR 13.4).

[0213] The CHA thus obtained had a Cu: Al molar ratio of 0.43, a Mn: Cu molar ratio of 0.15, a Ca: Cu molar ratio of 0.15, a (Cu+Mn+Ca): Al molar ratio of 0.56 and a Cu content of 7.0 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 21 (Ex21): CuMnZnCHA

[0214] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.6 g of copper (II) acetylacetonate, 10.8 g of Mn(III) acetylacetonate, 3.5 g of Zn (II) acetylacetonate, and 93.0 g of CHA (SAR 13.4).

[0215] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Zn: Cu molar ratio of 0.30, a (Cu+Mn+Zn): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 22 (Ex22): CuMnYCHA

[0216] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.6 g of copper (II) acetylacetonate, 10.8 g of Mn(III) acetylacetonate, 5.3 g of Y (III) acetylacetonate, and 92.6 g of CHA (SAR 13.4).

[0217] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Y: Cu molar ratio of 0.30, a (Cu+Mn+Y): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 23 (Ex23): CuMnZrCHA

[0218] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.6 g of copper (II) acetylacetonate, 10.8 g of Mn(III) acetylacetonate, 6.4 g of Zr (IV) acetylacetonate, and 92.4 g of CHA (SAR 13.4).

[0219] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Zr: Cu molar ratio of 0.30, a (Cu+Mn+Zr): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 24 (Ex24): CuMnCeCHA

[0220] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.6 g of copper (II) acetylacetonate, 4.6 g of Mn(III) acetylacetonate, 10.0 g of Ce (III) acetylacetonate, and 91.7 g of CHA (SAR 13.4).

[0221] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.30, a Ce: Cu molar ratio of 0.52, a (Cu+Mn+Ce): Al molar ratio of 0.38 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 25 (Ex25): CuMnPrCHA

[0222] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.6 g of copper (II) acetylacetonate, 10.8 g of Mn(III) acetylacetonate, 5.8 g of Pr (III) acetylacetonate, and 91.9 g of CHA (SAR 13.4).

[0223] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Pr: Cu molar ratio of 0.30, a (Cu+Mn+Pr): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 26 (Ex26): CuMnFeAEI

[0224] This material was prepared following the method described in Comparative Example 1, with the exception that the mixture comprised 11.5 g of copper (II) acetylacetonate, 10.8 g of Mn(III) acetylacetonate, 4.7 g of Fe(III) acetylacetonate and 93.0 g of AEI (SAR 16).

[0225] The AEI thus obtained had a Cu: Al molar ratio of 0.24, a Mn: Cu molar ratio of 0.70, a Fe: Cu molar ratio of 0.30, a (Cu+Mn+Fe): Al molar ratio of 0.48 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 27 (Ex27): CuMnSrCHA

[0226] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 10.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 2.8 g of Sr (NO.sub.3) 2, 11.4 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 92.7 g of CHA (SAR 13.4).

[0227] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Sr: Cu molar ratio of 0.30, a (Cu+Mn+Sr): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Example 28 (Ex28): CuMnMgCHA

[0228] This material was prepared following the method described in Comparative Example 2, with the exception that the mixture comprised 10.2 g of Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O, 3.4 g of Mg (NO.sub.3) 2.6H.sub.2O, 11.4 g of Mn(NO.sub.3).sub.2 aqueous solution (Mn content 14.8 wt %) and 92.7 g of CHA (SAR 13.4).

[0229] The CHA thus obtained had a Cu: Al molar ratio of 0.21, a Mn: Cu molar ratio of 0.70, a Mg: Cu molar ratio of 0.30, a (Cu+Mn+Mg): Al molar ratio of 0.42 and a Cu content of 3.5 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Measurement of NO.sub.x Conversion and N.sub.2O Reduction

[0230] The Comparative Examples and Examples according to the present invention, as listed above, were tested for their reaction behavior in NO.sub.x conversion and N.sub.2O reduction. The Examples according to the present invention were compared with zeolites comprising copper only, or only copper and manganese, but no metal M. These comparative tests illustrate the low temperature performance and durability benefits of the present invention for SCR application. The measurements were performed using a conventional plug flow model. In these measurements gas streams, simulating lean burn exhaust gas from the engine, were passed over and through meshed particles of test samples under conditions of varying temperature and the effectiveness of the sample in NO.sub.x reduction was determined by means of on-line FTIR (Fourier Transform Infra-Red) spectrometer. Two different testing conditions were carried out with NO only and NO.sub.2/NO.sub.x=25% to simulate the close-coupled and underfloor SCR catalyst position, respectively.

[0231] Table 1 below details the full experimental parameters employed in the generation of the data included herein.

TABLE-US-00001 TABLE 1 Model Gas testing conditions Concentration/Setting Concentration/Setting Component/Parameter (NO only) (25% NO.sub.2) NH.sub.3 750 ppm 750 ppm NO 500 ppm 375 ppm NO.sub.2 125 ppm H.sub.2O 4% 4% O.sub.2 5% 5% Temperature Ramp 600 to 100 C. @ 2 C./min Sample mass 180 mg Particle size of sample 300-500 m GHSV 250,000 h.sup.1

[0232] Table 2 shows the low temperature NO.sub.x conversion and N.sub.2O formation after 100 h of hydrothermal ageing at 650 C.

TABLE-US-00002 TABLE 2 NO.sub.x conversion for NO only and 25% NO.sub.2 at 175 C. and N.sub.2O selectivity at 300 C. in % for samples that were aged for 100 h at 650 C. 650 C., 100 h, hydrothermally aged NO only 25% NO.sub.2 NO.sub.x [%], N.sub.2O [%], NOx [%], N.sub.2O [%], Name 175 C. 300 C. 175 C. 300 C. CE1 25.91 1.74 57.71 3.65 CE2 58.46 2.55 74.78 3.88 CE3 62.17 2.79 73.34 3.59 CE4 44.28 2.30 65.74 3.58 CE5 23.97 1.35 55.32 2.43 CE6 31.41 2.02 CE7 37.10 1.17 CE8 45.80 1.88 CE9 52.68 0.82 68.15 1.32 CE10 20.98 2.06 53.72 3.74 CE11 37.6 1.18 65.52 2.47 CE12 33.81 1.48 59.75 2.71 Ex1 53.51 0.95 73.60 1.93 Ex2 56.60 0.90 74.88 1.74 Ex3 60.19 0.81 76.03 1.58 Ex4 69.20 0.85 81.87 1.51 Ex5 50.82 1.19 71.82 2.21 Ex6 67.15 1.66 78.54 2.38 Ex7 67.18 1.84 78.76 2.64 Ex8 52.79 1.11 71.33 1.90 Ex9 27.94 1.33 55.85 1.92 Ex10 54.70 0.78 73.38 1.48 Ex11 55.27 0.63 73.37 1.13 Ex12 54.64 0.89 73.58 1.55 Ex13 55.49 0.75 74.2 1.36 Ex14 39.31 1.43 64.57 2.50 Ex15 70.05 1.64 80.77 2.25 Ex16 66.26 1.76 78.35 2.48 Ex17 43.84 1.21 65.62 2.15 Ex18 47.92 1.03 67.30 1.65 Ex19 63.67 1.57 74.62 2.17 Ex20 67.17 1.89 77.49 2.54 Ex21 51.37 0.78 71.46 1.40 Ex22 55.78 0.78 74.43 1.38 Ex23 54.89 0.79 73.44 1.54 Ex24 53.51 1.17 73.02 2.08 Ex25 57.98 0.76 78.47 1.34 Ex26 51.45 0.83 70.25 1.61 Ex27 51.79 0.80 1.45 Ex28 52.48 0.77 1.41

[0233] The data above show the excellent low temperature NO.sub.x conversion after hydrothermal ageing when combining Cu, Mn and a further element M.

[0234] For example, Ex4 (CuMnFeCHA) had a NO.sub.x conversion of 69.2% at 175 C. after hydrothermal ageing, compared to 25.91% of CE1 (CuCHA) and 52.82% of CE9 (CuMnCHA) under NO only SCR condition, whereas the N.sub.2O selectivity of Ex4 is much lower than CE1. Similar benefit was also shown under 25% NO.sub.2 SCR condition. Further examples are the NO.sub.x conversion of 55.78% of Ex22 (CuMnYCHA), 57.98% of Ex25 (CuMnPrCHA), 55.27% of Ex11 (CuMnSmCHA).

[0235] FIG. 3 shows the NO.sub.x conversion and the N.sub.2O reduction, each in percent, for CE11, CE12, Ex17, Ex18, Ex19 and Ex20 at 175% under NO only and 25% NO.sub.2 conditions. CE11 and CE12 represent chabazites promoted with Cu, Mn and an alkali metal, which is either K (CE11) or Na (CE12). Examples 17 to 20, 27 and 28 represent chabazites promoted with Cu, Mn and an alkaline earth metal selected from Mg, Ca, Sr or Ba. The examples comprising an alkaline earth metal show a better NO.sub.x conversion at 175 C. under both NO only and 25% NO.sub.2 conditions, and the N.sub.2O reduction is comparable for all samples at both conditions.

[0236] The testing data of certain examples are shown in FIG. 1-FIG. 3. The ageing was carried out at 650 C. for 100 h under hydrothermal conditions (10% H.sub.2O, 10% O.sub.2).