(12) United States Patent
`Bull et a1.
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 7,601,662 B2
`Oct. 13, 2009
`
`US007601662B2
`
`(54)
`
`(75)
`
`COPPER CHA ZEOLITE CATALYSTS
`
`Inventors: Ivor Bull, LudWigshafen (DE);
`Wen-Mei Xue, Dayton, NJ (US);
`Patrick Burk, Freehold, NJ (US); R.
`Samuel Boorse, Skillman, NJ (US);
`William M. JagloWski, West Orange, NJ
`(US); Gerald S. Koermer, Basking
`Ridge, NJ (US); Ahmad Moini,
`Princeton, NJ (US); Joseph A. Patchett,
`Basking Ridge, NJ (US); Joseph C.
`Dettling, Howell, NJ (US); Matthew T.
`Caudle, Hamilton, NJ (US)
`
`(73)
`
`Assignee: BASF Catalysts LLC, Florham Park, NJ
`(Us)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21)
`
`(22)
`
`(65)
`
`(60)
`
`(51)
`
`(52)
`
`(58)
`
`(56)
`
`Appl. No.: 12/038,423
`
`Filed:
`
`Feb. 27, 2008
`
`Prior Publication Data
`
`US 2008/0226545 A1
`
`Sep. 18, 2008
`
`Related U.S. Application Data
`
`Provisional application No. 60/891,835, ?led on Feb.
`27, 2007.
`
`Int. Cl.
`(2006.01)
`B01J 29/06
`U.S. Cl. ....................... .. 502/60; 502/208; 502/214;
`423/700
`Field of Classi?cation Search ................. .. 502/ 60,
`502/208, 214; 423/700
`See application ?le for complete search history.
`
`References Cited
`
`U.S. PATENT DOCUMENTS
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`2002/0016252 A1* 2/2002 Takahashi et a1. ........... .. 502/71
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`2004/ 0209760 A1 10/2004 Yoshikawa
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`2/2005 Patchett et al.
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`6/2006 Yuen
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`6/2007 Liu et al.
`2007/0286798 A1 12/2007 Cao et al.
`2008/0241060 A1 10/2008 Li et al.
`
`FOREIGN PATENT DOCUMENTS
`
`6/1990
`3941541 A1
`DE
`5/2001
`10059520
`DE
`11/1990
`0396085
`EP
`0624393 A1 11/1994
`EP
`0773057 A1
`5/1997
`EP
`0950800 A2 10/1999
`EP
`1837489 A1
`9/2007
`EP
`05-057194
`12/1992
`JP
`6-48725
`2/1994
`JP
`WO-99/56859
`11/1999
`WO
`WO-03/035549 A1
`5/2003
`WO
`WO WO-2007/004774 A1
`1/2007
`
`(Continued)
`OTHER PUBLICATIONS
`
`Li, Yuejin et al., “Selective NH3 Oxidation to N2 in a Wet Stream”,
`Applied Catalysis B.‘ Environmental 13, (1997), p. 131-139.
`
`(Continued)
`Primary ExamineriEliZabeth D Wood
`(74) Attorney, Agent, or FirmiScott S. Servilla; Diehl
`Servilla LLC; Melanie L. BroWn
`
`(57)
`
`ABSTRACT
`
`Zeolite catalysts and systems and methods for preparing and
`using Zeolite catalysts having the CHA crystal structure are
`disclosed. The catalysts can be used to remove nitrogen
`oxides from a gaseous medium across a broad temperature
`range and exhibit hydrothermal stable at high reaction tem
`peratures. The Zeolite catalysts include a Zeolite carrier hav
`ing a silica to alumina ratio from about 15:1 to about 256:1
`and a copper to alumina ratio from about 0.25:1 to about 1:1.
`
`38 Claims, 11 Drawing Sheets
`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 1 of 28
`
`

`
`US 7,601,662 B2
`Page 2
`
`FOREIGN PATENT DOCUMENTS
`
`1/2007
`WO WO-2007/005308 A2
`2/2008
`WO WO-2008/019585 A1
`10/2008
`WO WO-2008/118434 A1
`WO WO-2008/132452 A2 11/2008
`
`OTHER PUBLICATIONS
`
`Rebrov, E. V., et al., “Development of the Kinetic Model of Platinum
`Catalyzed Ammonia Oxidation in a Microreactor”, Chemical Engi
`neering Journal 90, (2002), p. 61-76.
`Baerlocher, CH. et al., “Atlas of Zeolite Framework Types”,
`ElsevieriFifth Revised Edition, (2001), 5 pages.
`Medros, F. G., et al., “Dual-Catalyst System to Broaden the Window
`of Operability in the Reduction of NOx with Ammonia”, Ind. Eng.
`Chem. Res. 28, (1989), p. 1171-1177.
`Akolekar, Deepak B., et al., “FTIR Investigations of the Absorption
`and
`Disproportionation
`of NO on
`Cu-Exchanged
`Silicoaluminophosphate of Type 34”, J'. Chem. Soc. , Faraday Trans.,
`94(1), (1998), p. 155-160.
`Torre-Abreau, C. et al., “Selective Catalytic Reduction of NO on
`Copper-Exchanged Zeolites: The Role of The Structure of the Zeolite
`in the Nature of Copper-Active Sites”, Catalysis Today 54, (1999), p.
`407-418.
`Prakash, A. M., et al., “Synthesis of SAPO-34: High Silicon Incor
`poration in the Presence of Morpholine as Template”, .1. Chem. Soc.
`Faraday Trans. 90(15), (1994), 2291-2296.
`UZunova, Ellie L., et al., “Adsorption of NO on Cu-SAPO-34 and
`Co-SAPO-34; A Periodic DFT Study”, J'. Phys. Chem C2008, 2632
`2639.
`Ishihara, Tatsumi et al., “Thermostable Molecular Sieves,
`Silicoaluminophosphate (SAPO)-34, for the Removal of NOx with
`C3H6 in the Coexistence of O2, H20, and S02”, Ind. Eng. Chem.
`Res, 36, (1997), 17-22.
`Palella, B. I., et al., “On the hydrothermal stability of CuAPSO-34
`microporous catalysts for N20 decomposition: a comparison with
`CuZSM-5”, Journal ofCatalysts 21 7*Academic Press, (2003), 100
`106.
`Frache, A. et al., “Spectroscopic characterisation of microporous
`aluminophosphate materials with potential application in environ
`mental catalysis”, Catalysis Today 77, (2003), 371-384.
`Frache, A. et al., “Synthesis, Spectroscopic and Catalytic Properties
`of Cobalt and Copper Ions in Aluminophosphates with Chabasite
`Like Structure, Studies of the NO Reactivity”, Studies in Surface
`Science and Catalysis 140, (2001), 269-277.
`Frache, A. et al., “Catalytic DeNOx activity of cobalt and copper ions
`in microporous MeALPO-34 and MeAPSO-34”, Catalysis Today
`75(2002), 359-365.
`Treacy, M.M. J ., et al., “Proceedings of the 12th International Zeolite
`Conference”, Materials Research Society Conference Proceedings
`IV, (Jul. 5-10, 1998), 6 pp.
`Akolekar, Deepak B., et al., “FTIR investigations of the adsorption
`and
`disproportionation
`of NO on
`Cu-exchanged
`silicoaluminophosphate of type 34”, J'. Chem. Soc., Faraday Trans.,
`94(1), (1998), 155-160.
`
`Barger, Paul T., et al., “Hydrothermal Stability of SAPO-34 in the
`Methanol-to-Ole?ns Process”, T ha Arabian Journal for Science and
`Engineering, vol. 21, No. 2, (Apr. 1996), 10 pp.
`Marchese, L. et al., “ALPO-34 and SAPO-34 synthesized by using
`morpholine as templating agent. FTIR and FT-Raman studies of the
`host-guest and guest-guest interactions within the Zeolitic frame
`work”, Microporous and Mesoporous Materials 30, (1999), 145-153.
`Ishihara, Tatsumi et al., “Copper Ion-Exchanged SAPO-34 as a
`Thermostable Catalyst for Selective Reduction of NO with C3H6”,
`Journal ofCatalysis 169, Article No. CA971681, (1997), 93-102.
`“Fourth International Congress on Catalysis and Automotive Pollu
`tion Control”, (Apr. 1997), 7 pp.
`Palella, B. I., et al., “On the hydrothermal stability of CuAPSO-34
`microporous catalysts for N20 decomposition: a comparison with
`CuZSM-5”, Journal ofCatalysis 217, (2003), 100-106.
`Chen, Jiesheng et al., “Silicoaluminophosphate number eighteen
`(SAPO-18): a new microporous solid acid catalyst”, Catalysis Let
`ters 28, (1994), 241-248.
`Exchanged
`Ion
`“Copper
`al.,
`Ishihara,
`Tatsumi
`et
`Silicoaluminophosphate (SAPO) as a Thermostable Catalyst for
`Selective Reduction of NOx with Hydrocarbons”, Studies in Surface
`Science andDatalysis, vol. 84, (1994), 1493-1500.
`Frache, A. et al., “CuAPSO-34 catalysts for N20 decomposition in
`the presence of H20. A study of Zeolite structure stability in com
`parison to Cu-SAPO-34 and Cu-ZSM-5”, Topics in Catalysis vol. 22,
`Nos. 1/2, (2003), 5 pp.
`Zelenka, P. et al., “Exhaust gas aftetreatment systems for diesel
`engines with respect to future emission legislation”, 1993, 13 pp.
`PCT International Search Report & Written Opinion for PCT/
`US2008/055140 dated Aug. 11, 2008, 11 pp.
`Barthomeuf, Denise “Journal: NATO ASI Series, Series C: Math
`ematical and Physical Sciences Issue 444”, Generation of acidicity
`(amount and strength) in siliconaluminophosphates (SAPO zeolites),
`Examples ofSAPO-S; pp. 375-390, (1994), 17 pgs.
`Ashtekar, Sunil et al., “Small-Pore Molecular Sieves SAPO-34 and
`SAPO-44 with ChabaZite Structure: A Study of Silicon Incorpora
`tion”, .1. Phys. Chem. 1994, 98, (1994),4878-4883.
`Ishihara, Tatsumi et al., “Selective Reduction of Nitrogen Monoxide
`with Propene over Cu-Silico-aluminophosphate (SAPO) under Oxi
`diZing Atmosphere”, The Chemical Society of Japan (1992), 2119
`2122.
`“PCT International Search Report for PCT/US2008/055148”, 7 pgs,
`Oct. 2008.
`“PCT Written Opinion for PCT/US2008/055148”, 6 pgs, Feb. 2007.
`Hartmann,
`Martin
`et
`al.,
`“Transition-Metal
`Ions
`in
`Aluminophosphate and Silicoaluminophosphate Molecular Sieves:
`Location, Interaction with Adsorbates and Catalytic Properties”,
`Chem. Rev. 99 (3), (1999), 635-663.
`“Chinese Journal of Catalysis”, Thermal and Hydrothermal Stability
`ofSAPO-34 Molecular Sieve, vol. 17, No. 6, (Nov. 1996), 9 pgs.
`PCT International Search Report and Written Opinion in PCT/
`US2009/032610, (Jul. 16, 2009), 20 pgs.
`Machine Translation from EPO for DE 3941541 A1, 8 pgs.
`
`* cited by examiner
`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 2 of 28
`
`

`
`US. Patent
`
`0a. 13, 2009
`
`Sheet 1 0f 11
`
`US 7,601,662 B2
`
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`
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`Umicore AG & Co. KG
`Exhibit 1001
`Page 3 of 28
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`Umicore AG & Co. KG
`Exhibit 1001
`Page 4 of 28
`
`

`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 5 of 28
`
`

`
`US. Patent
`
`0a. 13, 2009
`
`Sheet 4 0f 11
`
`US 7,601,662 B2
`
`25%
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`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 6 of 28
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`

`
`US. Patent
`
`0a. 13, 2009
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`Sheet 5 0f 11
`
`US 7,601,662 B2
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`Page 7 of 28
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`

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`US. Patent
`
`Oct. 13, 2009
`
`Sheet 6 0f 11
`
`US 7,601,662 B2
`
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`$TGRAGE RELEASE
`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 8 of 28
`
`

`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 9 of 28
`
`

`
`US. Patent
`
`0a. 13, 2009
`
`Sheet 8 0f 11
`
`US 7,601,662 B2
`
`"Q" ()uGHAz 3.66 000% Gui), iresh, NQX
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`Umicore AG & Co. KG
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`Page 10 of 28
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`

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`US. Patent
`
`Oct. 13, 2009
`
`Sheet 9 0f 11
`
`US 7,601,662 B2
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`Page 11 of 28
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`U.S. Patent
`
`Oct. 13, 2009
`
`Sheet 10 0f 11
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`US 7,601,662 B2
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`US. Patent
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`0a. 13, 2009
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`US 7,601,662 B2
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`Umicore AG & Co. KG
`Exhibit 1001
`Page 13 of 28
`
`

`
`US 7,601,662 B2
`
`1
`COPPER CHA ZEOLITE CATALYSTS
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`This application claims the bene?t of priority under 35
`U.S.C. § 119(e) to Us. Patent Application No. 60/891,835,
`?led Feb. 27, 2007, Which is hereby incorporated by reference
`in its entirety.
`
`TECHNICAL FIELD
`
`Embodiments of the invention relate to Zeolites that have
`the CHA crystal structure, methods for their manufacture,
`and catalysts comprising such Zeolites. More particularly,
`embodiments of the invention pertain to copper CHA Zeolite
`catalysts and methods for their manufacture and use in
`exhaust gas treatment systems.
`
`BACKGROUND ART
`
`5
`
`20
`
`2
`more embodiments of the present invention provide a catalyst
`material Which exhibits excellent hydrothermal stability and
`high catalytic activity over a Wide temperature range. When
`compared With other Zeolitic catalysts that ?nd application in
`this ?eld, such as Fe Beta Zeolites, copper CHA catalyst
`materials according to embodiments of the present invention
`offer improved loW temperature activity and hydrothermal
`stability.
`One embodiment of the invention relates to a catalyst com
`prising a Zeolite having the CHA crystal structure and a mole
`ratio of silica to alumina greater than about 15 and an atomic
`ratio of copper to aluminum exceeding about 0.25. In a spe
`ci?c embodiment, the mole ratio of silica to alumina is from
`about 15 to about 256 and the atomic ratio of copper to
`aluminum is from about 0.25 to about 0.50. In a more speci?c
`embodiment, the mole ratio of silica to alumina is from about
`25 to about 40. In an even more speci?c embodiment, the
`mole ratio of silica to alumina is about 30. In one particular
`embodiment, the atomic ratio of copper to aluminum is from
`about 0.30 to about 0.50. In a speci?c embodiment, the atomic
`ratio of copper to aluminum is about 0.40. In a speci?c
`embodiment, the mole ratio of silica to alumina is from about
`25 to about 40 and the atomic ratio of copper to aluminum is
`from about 0.30 to about 0.50. In another speci?c embodi
`ment, the silica to alumina is about 30 and the atomic ratio of
`copper to alumina is about 0.40.
`In a particular embodiment, the catalyst contains ion-ex
`changed copper and an amount of non-exchanged copper
`suf?cient to maintain NOx conversion performance of the
`catalyst in an exhaust gas stream containing nitrogen oxides
`after hydrothermal aging of the catalyst. In one embodiment,
`the NOx conversion performance of the catalyst at about 200°
`C. after aging is at least 90% of the NOx conversion perfor
`mance of the catalyst at about 200° C. prior to aging. In a
`particular embodiment, the catalyst contains at least about
`2.00 Weight percent copper oxide.
`In at least one embodiment, the catalyst is deposited on a
`honeycomb substrate. In one or more embodiments, the hon
`eycomb substrate comprises a Wall ?oW substrate. In other
`embodiments, the honeycomb substrate comprises a How
`through substrate. In certain embodiments, at least a portion
`of the How through substrate is coated With CuCHA adapted
`to reduce oxides of nitrogen contained in a gas stream ?oWing
`through the substrate. In a speci?c embodiment, at least a
`portion of the How through substrate is coated With Pt and
`CuCHA adapted to oxidiZe ammonia in the exhaust gas
`stream.
`In embodiments that utiliZe a Wall ?oW substrate, at least a
`portion of the Wall ?oW substrate is coated With CuCHA
`adapted to reduce oxides of nitrogen contained in a gas stream
`?oWing through the substrate. In other embodiments, at least
`a portion of the Wall ?oW substrate is coated With Pt and
`CuCHA adapted to oxidiZe ammonia in the exhaust gas
`stream.
`In a speci?c embodiment, a catalyst article comprises a
`honeycomb substrate having a Zeolite having the CHA crystal
`structure deposited on the substrate, the Zeolite having a mole
`ratio of silica to alumina greater than about 15 and an atomic
`ratio of copper to aluminum exceeding about 0.25 and con
`taining an amount of free copper exceeding ion-exchanged
`copper. In one embodiment, the free copper is present in an
`amount suf?cient to prevent hydrothermal degradation of the
`nitrogen oxide conversion of the catalyst. In one or more
`embodiments, the free copper prevents hydrothermal degra
`dation of the nitrogen oxide conversion of the catalyst upon
`hydrothermal aging. The catalyst may further comprise a
`
`25
`
`30
`
`35
`
`40
`
`Zeolites are aluminosilicate crystalline materials having
`rather uniform pore siZes Which, depending upon the type of
`Zeolite and the type and amount of cations included in the
`Zeolite lattice, typically range from about 3 to 10 Angstroms
`in diameter. Both synthetic and natural Zeolites and their use
`in promoting certain reactions, including the selective reduc
`tion of nitrogen oxides With ammonia in the presence of
`oxygen, are Well knoWn in the art.
`Metal-promoted Zeolite catalysts including, among others,
`iron-promoted and copper-promoted Zeolite catalysts, for the
`selective catalytic reduction of nitro gen oxides With ammonia
`are knoWn. Iron-promoted Zeolite beta has been an effective
`catalyst for the selective reduction of nitrogen oxides With
`ammonia. Unfortunately, it has been found that under harsh
`hydrothermal conditions, such as reduction of NOx from gas
`exhaust at temperatures exceeding 5000 C., the activity of
`many metal-promoted Zeolites begins to decline. This decline
`in activity is believed to be due to destabiliZation of the Zeolite
`such as by dealumination and consequent reduction of metal
`containing catalytic sites Within the Zeolite. To maintain the
`overall activity of NOx reduction, increased levels of the
`iron-promoted Zeolite catalyst must be provided. As the levels
`of the Zeolite catalyst are increased to provide adequate NOx
`removal, there is an obvious reduction in the cost ef?ciency of
`45
`the process for NOx removal as the costs of the catalyst rise.
`There is a desire to prepare materials Which offer loW
`temperature SCR activity and/ or improved hydrothermal
`durability over existing Zeolites, for example, catalyst mate
`rials Which are stable at temperatures up to at least about 650°
`C. and higher.
`
`50
`
`SUMMARY
`
`Aspects of the invention are directed to Zeolites that have
`the CHA crystal structure (as de?ned by the International
`Zeolite Association), catalysts comprising such Zeolites, and
`exhaust gas treatments incorporating such catalysts. The cata
`lyst may be part of an exhaust gas treatment system used to
`treat exhaust gas streams, especially those emanating from
`gasoline or diesel engines.
`One embodiment of the present invention pertains to cop
`per CHA catalysts and their application in exhaust gas sys
`tems such as those designed to reduce nitrogen oxides. In
`speci?c embodiments, novel copper chabaZite catalysts are
`provided Which exhibit improved NH3 SCR of NOx. The
`copper chabaZite catalysts made in accordance With one or
`
`55
`
`60
`
`65
`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 14 of 28
`
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`US 7,601,662 B2
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`binder. In particular embodiments, the ion-exchanged copper
`is exchanged using copper acetate.
`Other aspects of the invention relate to exhaust gas treat
`ment systems incorporating catalysts of the type described
`above. Still other aspects relate to a process for the reduction
`of oxides of nitrogen contained in a gas stream in the presence
`of oxygen Wherein said process comprises contacting the gas
`stream With the catalyst described above.
`Another aspect pertains to an exhaust gas treatment system
`comprising an exhaust gas stream containing NOx, and a
`catalyst described above effective for selective catalytic
`reduction of at least one component of NOx in the exhaust gas
`stream. Still another aspect pertains to an exhaust gas treat
`ment system comprising an exhaust gas stream containing
`ammonia and a catalyst as described above effective for
`destroying at least a portion of the ammonia in the exhaust gas
`stream.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N2O generated
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures for CuCHA prepared according to the methods of
`Example 1;
`FIG. 1A is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N2O generated
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures for CuCHA prepared according to the methods of
`Examples 1 and 1A;
`FIG. 2 is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N2O generated
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures, for CuCHA prepared according to the methods of
`Example 2;
`FIG. 3 is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N2O generated
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures for CuCHA prepared according to the methods of
`Example 3;
`FIG. 4 is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N2O generated
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures for CuCHA prepared according to the methods of
`Example 4;
`FIG. 5 is a graph depicting effects of CO, propene, n-octane
`and Water on the CuCHA SCR activity at various tempera
`tures;
`FIG. 5A is a graph shoWing the amount of HCs that are
`stored, released, deposited as coke and bumt-off coke for a
`sample tested in accordance With Example 12A;
`FIG. 5B is a bar chart shoWing hydrocarbon performance
`of CuCHA compared With CuY and Fe beta Zeolites in accor
`dance With Example 12A;
`FIG. 6 is a graph depicting emissions of NH3, NOx (:NO+
`NO2), N20, and N2 from the AMOX catalyst outlet, given as
`ppm on a nitrogen atom basis prepared and aged according to
`the method of Examples 13 and 14;
`FIG. 7 is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N2O generated
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures, for CuCHA prepared according to the methods of
`Example 16;
`FIG. 8 is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N2O generated
`
`4
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures, for CuCHA prepared according to the methods of
`Example 17;
`FIG. 9 is a graph depicting nitrogen oxides removal e?i
`ciency (%), ammonia consumption (%) and N20 generated
`(ppm) of CuCHA catalyst as a function of reaction tempera
`tures for CuCHA prepared according to the methods of
`Example 18;
`FIGS. 10A, 10B, and 10C are schematic depictions of three
`exemplary embodiments of the emissions treatment system
`of the invention;
`FIG. 11 is UV/VIS of Example 22 and 22A; and
`FIG. 12 is 27Al MAS NMR spectra of Example 22 and
`22A, compared With CHA and aged CHA samples.
`
`DETAILED DESCRIPTION
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`Before describing several exemplary embodiments of the
`invention, it is to be understood that the invention is not
`limited to the details of construction or process steps set forth
`in the folloWing description. The invention is capable of other
`embodiments and of being practiced or being carried out in
`various Ways.
`In one embodiment of the invention, Zeolites having the
`CHA structure such as chabaZite are provided. In one or more
`embodiments, a Zeolite having the CHA crystal structure and
`a mole ratio of silica to alumina greater than about 15 and an
`atomic ratio of copper to aluminum exceeding about 0.25 is
`provided. In speci?c embodiments, the mole ratio of silica to
`alumina is about 30 and the atomic ratio of copper to alumi
`num is about 0.40. Other Zeolites having the CHA structure,
`include, but are not limited to SSZ-13, LZ-218, Linde D,
`Linde R, Phi, ZK-14, and ZYT-6.
`Synthesis of the Zeolites having the CHA structure can be
`carried out according to various techniques knoWn in the art.
`For example, in a typical SSZ-13 synthesis, a source of silica,
`a source of alumina, and an organic directing agent are mixed
`under alkaline aqueous conditions. Typical silica sources
`include various types of fumed silica, precipitated silica, and
`colloidal silica, as Well as silicon alkoxides. Typical alumina
`sources include boehmites, pseudo-boehmites, aluminum
`hydroxides, aluminum salts such as aluminum sulfate, and
`aluminum alkoxides. Sodium hydroxide is typically added to
`the reaction mixture, but is not required. A typical directing
`agent for this synthesis is adamantyltrimethylammonium
`hydroxide, although other amines and/or quaternary ammo
`nium salts may be substituted or added to the latter directing
`agent. The reaction mixture is heated in a pres sure vessel With
`stirring to yield the crystalline SSZ-13 product. Typical reac
`tion temperatures are in the range of 150 and 180° C. Typical
`reaction times are betWeen 1 and 5 days.
`At the conclusion of the reaction, the product is ?ltered and
`Washed With Water. Alternatively, the product may be centri
`fuged. Organic additives may be used to help With the han
`dling and isolation of the solid product. Spray-drying is an
`optional step in the processing of the product. The solid
`product is thermally treated in air or nitrogen. Alternatively,
`each gas treatment can be applied in various sequences, or
`mixtures of gases can be applied. Typical calcination tem
`peratures are in the 4000 C. to 700° C. range.
`CuCHA Zeolite catalysts in accordance With one or more
`embodiments of the invention can be utiliZed in catalytic
`processes Which involve oxidiZing and/ or hydrothermal con
`ditions, for example in temperatures in excess of about 600°
`C., for example, above about 800° C. and in the presence of
`about 10% Water vapor. More speci?cally, it has been found
`that CuCHA Zeolite catalysts Which have been prepared in
`
`Umicore AG & Co. KG
`Exhibit 1001
`Page 15 of 28
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`US 7,601,662 B2
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`5
`accordance With embodiments of the invention have
`increased hydrothermal stability compared to CuY and
`CuBeta Zeolites. CuCHA Zeolite catalysts prepared in accor
`dance With embodiments of the invention yield improved
`activity in the selective catalytic reduction of NOx With
`ammonia, especially When operated under high temperatures
`of at least about 600° C., for example, about 800° C. and
`higher, and high Water vapor environments of about 10% or
`more. CuCHA has high intrinsic activity that enables use of
`loWer amounts of catalyst material, Which in turn should
`reduce backpressure of honeycomb substrates coated With
`Washcoats of CuCHA catalysts. In one or more embodiments,
`hydrothermal aging refers to exposure of catalyst to a tem
`perature of about 800° C. in a high Water vapor environments
`of about 10% or more, for at least about 5 to about 25 hours,
`and in speci?c embodiments, up to about 50 hours.
`Embodiments of this invention also pertain to a process for
`abatement of NO,C in an exhaust gas stream generated by an
`internal combustion engine utiliZing CuCHA Zeolite catalysts
`having a mole ratio of silica to alumina greater than about 15
`and an atomic ratio of copper to aluminum exceeding about
`0.25. Other embodiments pertain to SCR catalysts compris
`ing a CuCHA Zeolite catalyst having a mole ratio of silica to
`alumina greater than about 1 5 and an atomic ratio of copper to
`aluminum exceeding about 0.25, and exhaust gas treatment
`systems incorporating CuCHA Zeolite catalysts. Still other
`embodiments pertain to ammonia oxidation (AMOX) cata
`lysts and exhaust gas treatment systems incorporating AMOX
`catalyst comprising a CuCHA Zeolite catalyst having a mole
`ratio of silica to alumina greater than about 15 and an atomic
`ratio of copper to aluminum exceeding about 0.25 . According
`to one or more embodiments, catalysts and systems utilize
`CuCHA catalysts having ion-exchanged copper and su?i
`cient excess free copper to prevent thermal degradation of the
`catalysts When operated under high temperatures of at least
`about 600° C., for example, about 800° C. and higher, and
`high Water vapor environments of about 10% or more.
`Experimentation has indicated that improved performance
`of catalysts in accordance With embodiments of the invention
`is associated With Cu loading. While Cu can be exchanged to
`increase the level of Cu associated With the exchange sites in
`the structure of the Zeolite, it has been found that it is bene?
`cial to leave non-exchanged Cu in salt form, for example, as
`CuSO4 Within the Zeolite catalyst. Upon calcination, the cop
`per salt decomposes to CuO, Which may be referred to herein
`as “free copper” or “soluble copper.” According to one or
`more embodiments, this free Cu is both active and selective,
`resulting in loW N2O formation When used in the treatment of
`a gas stream containing nitrogen oxides. Unexpectedly, this
`“free” Cu has been found to impart greater stability in cata
`lysts subjected to thermal aging at temperatures up to about
`800° C.
`While embodiments of the invention are not intended to be
`bound by a particular principle, it is believed that the rela
`tively small channel openings of CHA do not permit large
`molecular Weight hydrocarbons (HCs) typical of diesel fuel
`to enter and adsorb Within the CuCHA structure. Unlike other
`Zeolites like Beta or ZSM5, CHA catalysts prepared accord
`ing to embodiments of the invention have a relatively loW
`a?inity for adsorbing these large molecular Weight HC spe
`cies. This is a bene?cial property for use in selective catalytic
`reduction (SCR) catalysts.
`In systems that utiliZe an SCR doWnstream from a diesel
`oxidation catalyst (DOC), the properties of the CuCHA cata
`lysts provide one or more bene?cial results according to
`embodiments of the invention. During start-up and prolonged
`loW temperature operation, the SCR only or a diesel oxidation
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`catalyst (DOC) or DOC and catalyZed soot ?lter (CSF)
`upstream of the CuCHA SCR are not fully activated to oxi
`diZe the HCs. In accordance With one or more embodiments,
`because the CuCHA SCR catalyst is not in?uenced by HCs at
`loW temperature, it remains active over a Wider range of the
`loW temperature operation WindoW. According to one or more
`embodiments, loW temperature refers to temperatures about
`250° C. and loWer.
`According to one or more embodiments, the CuCHA cata
`lysts operate Within a loW temperature WindoW. Over time in
`an exhaust gas treatment system having a DOC pre-catalyst
`doWnstream from the engine folloWed by an SCR catalyst and
`a CSF, or a DOC pre-catalyst upstream from a CSF and SCR,
`the DOC Will tend to activate for both loW temperature light
`off and HC fuel burning. In such systems, it is bene?cial if the
`SCR catalyst can maintain its ability to operate at loW tem
`peratures. Since the oxidation catalysts Will lose their ability
`to oxidiZe NO to NO2, it is useful to provide an SCR catalyst
`that can treat NO as effectively as NO2. CuCHA catalysts
`produced in accordance With embodiments of the invention
`have the ability to reduce NO With NH3 at loW temperatures.
`This attribute can be enhanced by the addition of non-ex
`changed Cu to the Zeolite catalyst.
`According to embodiments of the invention, the SCR cata
`lyst can be in the form of self supporting catalyst particles or
`as a honeycomb monolith formed of the SCR catalyst com
`position. In one or more embodiments of the invention hoW
`ever, the SCR catalyst composition is disposed as a Washcoat
`or as a combination of Washcoats on a ceramic or metallic
`substrate, for example a honeycomb ?oW through substrate.
`In a speci?c embodiment of an emissions treatment system
`the SCR catalyst is formed from a Cu exchanged CHA Zeolite
`material having free copper in addition to ion-exchanged
`copper.
`When deposited on the honeycomb monolith substrates,
`such SCR catalyst compositions are deposited at a concen
`tration of at least about 0.5 g/in3 , for example, about 1.3 g/in3
`about 2.4 g/in3 or higher to ensure that the desired NOx
`reduction is achieved and to secure adequate durability of the
`catalyst over extended use.
`The term “SCR” catalyst is used herein in a broader sense
`to mean a select