# US 2019/0168199 A1 · Selective catalytic reduction articles and systems

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- Number: US 2019/0168199 A1
- Document ID: US20190168199A1
- Status: Published application
- Kind: A1
- Application number: 16/323,154
- Filed: 2017-08-04
- Published: 2019-06-06
- Earliest claimed: 2016-08-05
- Assignees: BASF SE
- Applicants: BASF Corporation
- Inventors: Jeff H. Yang; Wen-Mei Xue; Stanley A. Roth; Kenneth E. Voss; Qi Fu; Subramanian Prasad; Barbara K. Slawski; Jaya L. Mohanan; Sandip D. Shah
- Web page: https://patentgrep.com/patent/US20190168199A1

## CPC

- B01J 29/763: {CHA-type, e.g. Chabazite, LZ-218}
- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01D 53/9468: {in different layers}
- B01D 53/9472: {in different zones}
- B01J 29/072: Iron group metals or copper
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths
- B01J 37/0045: {Drying a slurry, e.g. spray drying}
- B01J 37/009: {Preparation by separation, e.g. by filtration, decantation, screening}
- B01J 37/0236: {Drying, e.g. preparing a suspension, adding a soluble salt and drying}
- B01J 37/0244: {Coatings comprising several layers}
- B01J 37/0246: {Coatings comprising a zeolite}
- B01J 37/06: Washing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/10: in the presence of water, e.g. steam
- B01J 37/30: Ion-exchange
- C01B 39/02: Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
- F01N 3/035: with catalytic reactors
- F01N 3/106: {Auxiliary oxidation catalysts}
- F01N 3/20: specially adapted for catalytic conversion (F01N3/22 takes precedence)
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- B01D 2255/20738: Iron
- B01D 2255/20761: Copper
- B01D 2255/50: Zeolites
- B01D 2255/9022: Two layers
- B01D 2255/9025: Three layers
- B01D 2255/9032: Two zones
- B01D 2255/9155: Wall flow filters
- B01D 2258/012: Diesel engines and lean burn gasoline engines
- B01J 2229/186: not in framework positions
- B01J 2229/36: Steaming
- F01N 2250/02: filtering and catalytic conversion
- F01N 2570/14: Nitrogen oxides
- F01N 2570/18: Ammonia
- Y02C 20/10: of nitrous oxide (N2O)
- Y02T 10/12: Improving ICE efficiencies
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Certain selective catalytic reduction (SCR) articles, systems and methods provide for high NOx conversion while at the same time low N2O formation. The articles, systems and methods are suitable for instance for the treatment of exhaust gas of diesel engines. Certain articles have zoned coatings disposed thereon, for example, a zoned coating comprising an upstream zone comprising a coating layer comprising a steam-activated iron-containing molecular sieve and a downstream zone comprising a coating layer comprising a high copper-containing molecular sieve.

## Claims

### Claim 1

A method for activating an iron-containing molecular sieve powder, the method comprising:
adding iron into a molecular sieve to form an iron-containing molecular sieve; and
carrying out steam-calcination of the iron-containing molecular sieve powder at a temperature of about 650° C. to about 750° C. for a period of about 20 minutes to about 2 hours in the presence of water vapor.

### Claim 2 (depends on 1)

The method of claim 1, wherein adding the iron into the molecular sieve comprises a process selected from the group consisting of ion-exchange, impregnation of an iron salt, and mixing a molecular sieve with iron oxide.

### Claim 3 (depends on 1)

A method of preparing a catalytic article, the method comprising applying to a substrate a catalytic coating comprising a steam-activated iron-containing molecular sieve powder prepared according to claim 1.

### Claim 4 (depends on 3)

The method of claim 3, wherein the coated substrate is adapted to achieve greater than 90% NOx conversion at 250° C. under fast SCR conditions without further steam-treatment.

### Claim 5

A selective catalytic reduction article comprising a substrate having a front upstream end and a rear downstream end defining an axial length and having a catalytic coating thereon, where the catalytic coating comprises:
a first coating layer comprising a steam-activated iron-containing molecular sieve; and
a second coating layer comprising a copper-containing molecular sieve.

### Claim 6 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the catalytic coating is zoned and comprises:
a first, upstream zone comprising the first coating layer comprising the steam-activated iron-containing molecular sieve; and
a second, downstream zone comprising the second coating layer comprising the copper-containing molecular sieve.

### Claim 7 (depends on 5)

The selective catalytic reduction article of claim 5,
wherein the substrate is a porous wall-flow filter or a flow-through monolith.

### Claim 8 (depends on 5)

The selective catalytic reduction article of claim 5, wherein one or both of the following conditions apply:
a weight ratio of the steam-activated iron-containing molecular sieve to the copper-containing molecular sieve is about 1:10 to about 10:1;
a weight ratio of iron oxide in the steam-activated iron-containing molecular sieve to copper oxide in the copper-containing molecular sieve is about 1:15 to about 15:1.

### Claim 9 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the steam-activated iron-containing molecular sieve includes iron oxide in an amount of about 1 wt % to about 15 wt %, based on the total weight of the iron-containing molecular sieve, and the copper-containing molecular sieve includes copper oxide in an amount of about 1 wt % to about 10 wt %, based on the total weight of the copper-containing molecular sieve.

### Claim 10 (depends on 5)

The selective catalytic reduction article of claim 5, wherein one or both of the following conditions apply:
the copper-containing molecular sieve has a Cu/Al atomic ratio of about 0.05 to about 0.55;
the steam-activated iron-containing molecular sieve has a Fe/Al atomic ratio of about 0.05 to about 2.0.

### Claim 11 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the first coating layer extends a distance from the front, upstream end of the substrate towards the rear, downstream end of the substrate and overlays a portion of the second coating layer, which extends from the rear, downstream end of the substrate a distance towards the front, upstream end of the substrate.

### Claim 12 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the first coating layer extends from the front, upstream end of the substrate to the rear, downstream end of the substrate and overlays an entirety of the second coating layer, which extends from the rear, downstream end of the substrate to the front, upstream end of the substrate.

### Claim 13 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the second coating layer extends a distance from the front, upstream end of the substrate towards the rear, downstream end of the substrate and overlays a portion of the first coating layer, which extends a distance from the rear, downstream end of the substrate towards the front, upstream end of the substrate.

### Claim 14 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the second coating layer extends from the front, upstream end of the substrate to the rear, downstream end of the substrate and overlays an entirety of the first coating layer, which extends from the rear, downstream end of the substrate to the front, upstream end of the substrate.

### Claim 15 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the first coating layer and the second coating layer are adjacent and do not overlay each other.

### Claim 16 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the first coating layer and the second coating layer are in direct contact with each other.

### Claim 17 (depends on 5)

The selective catalytic reduction article of claim 5, wherein the steam-activated iron-containing molecular sieve and the copper-containing molecular sieve are each 8-ring small pore molecular sieves.

### Claim 18 (depends on 17)

The selective catalytic reduction article of claim 17, wherein the steam-activated iron-containing molecular sieve and the copper-containing molecular sieve are both independently zeolites having a structure selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, SAS, SAT and SAV.

### Claim 19 (depends on 17)

The selective catalytic reduction article of claim 17, wherein each of the steam-activated iron-containing molecular sieve and the copper-containing molecular sieve are aluminosilicate zeolites having a CHA crystal structure and a silica to alumina ratio (SAR) of about 5 to about 40.

### Claim 20 (depends on 6)

The selective catalytic reduction article of claim 6, wherein the substrate includes an undercoat comprising an AMOx catalyst in the downstream zone.

### Claim 21

A selective catalytic reduction system comprising:
a first selective catalytic reduction article formed of a first substrate including a first catalytic coating layer comprising a steam-activated iron-containing molecular sieve; and
a second selective catalytic reduction article formed of a second substrate including a second catalytic coating layer comprising a copper-containing molecular sieve:
wherein the first selective catalytic reduction article and the second selective catalytic reduction article are in fluid communication.

### Claim 22 (depends on 21)

The selective catalytic reduction system of claim 21, wherein:
the first substrate of the first selective catalytic reduction article is zoned according to one of the claims of 5-20; and
the second selective catalytic reduction article formed of a second substrate includes a second catalytic coating layer comprising a cooper-containing molecular sieve,
wherein the first selective catalytic reduction article and the second selective catalytic reduction article are in fluid communication.

### Claim 23 (depends on 21)

The selective catalytic reduction system of claim 21, wherein the first substrate and the second substrate are each independently selected from the group consisting of a porous wall-flow filter and a flow-through monolith.

### Claim 24 (depends on 21)

The selective catalytic reduction system of claim 21, wherein the second substrate includes an undercoat comprising an AMOx catalyst.

### Claim 25 (depends on 5)

An exhaust gas treatment system comprising:
a selective catalytic reduction article according to claim 5;
a reductant injector in fluid communication with and upstream of the selective catalytic reduction article; and
optionally one or more of a diesel oxidation catalyst, a soot filter, an ammonia oxidation catalyst, and an internal combustion engine.

### Claim at position 26

26-27. (canceled)

### Claim 28 (depends on 5)

A method for treating an exhaust stream containing NOx,
comprising passing the exhaust stream through a selective catalytic reduction article of claim 5.

### Claim 29 (depends on 21)

An exhaust gas treatment system comprising:
a selective catalytic reduction system according to claim 21;
a reductant injector in fluid communication with and upstream of the selective catalytic reduction system; and
optionally one or more of a diesel oxidation catalyst, a soot filter, an ammonia oxidation catalyst, and in internal combustion engine.

### Claim 30 (depends on 21)

A method for treating an exhaust stream containing NOx, comprising passing the exhaust stream through a selective catalytic reduction system of claim 21.

### Claim 31 (depends on 25)

A method for treating an exhaust stream containing NOx, comprising passing the exhaust stream through an exhaust gas treatment system of claim 25.

### Claim 32 (depends on 29)

A method for treating an exhaust stream containing NOx, comprising passing the exhaust stream through an exhaust gas treatment system of claim 29.