# US 11,305,260 B2 · Catalyst for gasoline engine exhaust gas aftertreatment

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- Number: US 11,305,260 B2
- Document ID: US11305260B2
- Status: Granted
- Kind: B2
- Application number: 16/975,611
- Filed: 2019-02-22
- Published: 2020-12-31
- Granted: 2022-04-19
- Earliest claimed: 2018-02-26
- Assignees: BASF SE
- Applicants: BASF Corporation
- Inventors: Yun Fei Qi; Jun Cong Jiang; Shau Lin Chen; Weiyong Tang; Yu Lin Qiu; Liang Fang Lv; Yan Zhu Lei
- Web page: https://patentgrep.com/patent/US11305260B2

## CPC

- B01J 23/464: {Rhodium}
- B01D 53/945: {characterised by a specific catalyst}
- B01J 35/45: Nanoparticles
- B01J 35/57: Honeycombs
- B01J 35/613: {10-100 m2/g}
- B01J 35/615: {100-500 m2/g}
- B01J 35/657: {larger than 1000 nm}
- B01J 37/0201: {Impregnation}
- B01J 37/024: {Multiple impregnation or coating}
- B01J 37/088: {Decomposition of a metal salt}
- F01N 3/0222: {the structure being monolithic, e.g. honeycombs}
- F01N 3/035: with catalytic reactors
- F01N 3/101: {Three-way catalysts}
- F01N 3/2825: {Ceramics (F01N3/2832, F01N3/2835 take precedence)}
- F01N 13/16: Selection of particular materials
- B01D 2255/1021: Platinum
- B01D 2255/1023: Palladium
- B01D 2255/1025: Rhodium
- B01D 2255/2042: Barium
- B01D 2255/2061: Yttrium
- B01D 2255/2063: Lanthanum
- B01D 2255/2065: Cerium
- B01D 2255/2068: Neodymium
- B01D 2255/20715: Zirconium
- B01D 2255/9155: Wall flow filters
- B01D 2255/9202: Linear dimensions
- B01D 2255/9205: Porosity
- B01J 23/42: Platinum
- B01J 23/44: Palladium
- B01J 2523/00: Constitutive chemical elements of heterogeneous catalysts
- F01N 2330/06: Ceramic, e.g. monoliths
- F01N 2330/32: characterised by the shape, form or number of corrugations of plates, sheets or foils
- F01N 2370/02: used in catalytic reactors
- 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)
- 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)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A catalyst for gasoline engine exhaust gas after-treatment, comprising Pt and optionally at least one other platinum group metal on a hydrothermal stable support material which is coated onto a gasoline particulate filter. The catalyst oxidizes particulate matter trapped in the gasoline particulate filter under low temperature and abates NOx, CO and HC. Also a process for preparing the catalyst is disclosed, and a method for after-treatment of gasoline engine exhaust gas using the catalyst is disclosed.

## Claims

### Claim 1

A catalyst, comprising:
Pt, a hydrothermally stable support material, and
at least one functional additive chosen from magnesium oxide, calcium oxide, strontium oxide, barium oxide, gallium oxide, indium oxide, germanium oxide, antimony oxide, and mixtures thereof,
wherein the Pt and the hydrothermally stable support material are disposed on a gasoline particulate filter, and
the Pt is present in a catalytically effective amount to convert NOx, CO, and hydrocarbons in an exhaust gas to N2, CO2, and H2O and to cause oxidation of particulate matter trapped on the gasoline particulate filter.

### Claim 2

A catalyst coated onto a gasoline particulate filter, said catalyst comprising:
Pt;
at least one functional additive chosen from magnesium oxide, calcium oxide, strontium oxide, barium oxide, gallium oxide, indium oxide, germanium oxide, antimony oxide, and mixtures thereof;
a hydrothermally stable support material chosen from alumina, zirconia, ceria, silica, titania, a rare earth metal oxide other than ceria, and mixtures thereof;
optionally a platinum group metal chosen from Rh, Pd, Ru, Ir, and mixtures thereof; and
optionally a transition group metal chosen from Mn, Fe, Co, Ni, Cu, and mixtures thereof.

### Claim 3 (depends on 2)

The catalyst of claim 2, further comprising:
Rh; and
optionally a platinum group metal chosen from Pd, Ru, Ir, and mixtures thereof.

### Claim 4 (depends on 3)

The catalyst of claim 3, wherein the catalyst comprises:
from 0.01 wt. % to 3 wt % Pt, based on a calcined weight of the catalyst;
from 0.02 wt. % to 3 wt. % Rh, based on the calcined weight of the catalyst;
from 70 wt. % to 99 wt. % of the hydrothermally stable support material chosen from alumina, zirconia, ceria, silica, titania, a rare earth metal oxide other than ceria, and mixtures thereof, based on the calcined weight of the catalyst.

### Claim 5 (depends on 4)

The catalyst of claim 4, wherein the catalyst comprises:
from 0.02 wt. % to 1 wt. % Pt, based on the calcined weight of the catalyst;
from 0.04 wt. % to 1 wt. % Rh, based on the calcined weight of the catalyst;
from 80 wt. % to 99 wt. % of the hydrothermal stable support material chosen from alumina, zirconia, ceria, silica, titania, a rare earth metal oxide other than ceria, and mixtures thereof, based on the calcined weight of the catalyst.

### Claim 6 (depends on 2)

The catalyst of claim 2, wherein the catalyst comprises from 0.01 wt. % to 4 wt. % Pd, based on a calcined weight of the catalyst.

### Claim 7 (depends on 2)

The catalyst of claim 2, wherein a weight ratio of Pt:Rh ranges from 0.1 to 10, inclusive.

### Claim 8 (depends on 2)

The catalyst of claim 2, wherein a weight ratio of Pt:Pd is greater than or equal to 0.1.

### Claim 9 (depends on 2)

The catalyst of claim 2, wherein the catalyst is coated onto the gasoline particulate filter along the whole of or a part of an axial length or radial direction of the gasoline particular filter, on alternating channels, on a wall or in a porous wall, or a combination thereof.

### Claim 10 (depends on 2)

The catalyst of claim 2, wherein the gasoline particulate filter comprises a wall-flow filter comprising a honeycomb structure.

### Claim 11 (depends on 2)

The catalyst of claim 2, wherein a mean pore size of the gasoline particulate filter is from 10 μm to 24 μm.

### Claim 12 (depends on 1)

A process for preparing the catalyst of claim 1, said process comprising:
a) impregnating Pt and optionally a platinum group metal chosen from Rh, Pd, Ru, and Ir, optionally using one or more precursors thereof, onto the hydrothermally stable support material with sufficient water to achieve incipient wetness, adding at least one functional additive chosen from magnesium oxide, calcium oxide, strontium oxide, barium oxide, gallium oxide, indium oxide, germanium oxide, antimony oxide, and mixtures thereof, and optionally to dilute and/or mix with one or more materials independently chosen from transition group metals, binding materials and combinations thereof and/or precursors thereof, to form an aqueous slurry;
b) milling and coating the aqueous slurry onto the gasoline particulate filter; and
c) calcining the gasoline particulate filter coated with the aqueous slurry.

### Claim 13 (depends on 1)

A process for preparing the catalyst of claim 1, the process comprising:
a) impregnating Pt and optionally a platinum group metal chosen from Pd, Ru, and Ir, optionally using one or more precursors thereof, onto the hydrothermally stable support material with sufficient water to achieve incipient wetness, adding at least one functional additive chosen from magnesium oxide, calcium oxide, strontium oxide, barium oxide, gallium oxide, indium oxide, germanium oxide, antimony oxide, and mixtures thereof, and optionally to dilute and/or mix with one or more materials independently chosen from transition group metals, and binding materials and combinations thereof and/or precursors thereof, to form a first aqueous slurry;
b) impregnating Rh and optionally a platinum group metal chosen from Pd, Ru, and Ir, optionally using one or more precursors thereof, onto the hydrothermally stable support material with sufficient water to achieve incipient wetness and optionally to dilute and/or mix with one or more materials independently chosen from base metal oxides, transition group metals, and binding materials and combinations thereof and/or precursors thereof, to form a second aqueous slurry;
c) milling and coating the second aqueous slurry onto the gasoline particulate filter;
d) calcining the gasoline particulate filter coated with the second aqueous slurry;
e) milling and coating the first aqueous slurry onto the gasoline particulate filter; and
f) calcining the gasoline particulate filter coated with the first aqueous slurry.

### Claim 14 (depends on 13)

The process of claim 13, wherein a weight ratio of Pt:Pd in a) is greater than or equal to 0.1.

### Claim 15 (depends on 12)

A catalyst prepared according to the process of claim 12.

### Claim 16 (depends on 1)

A method for after treating an exhaust gas of a gasoline engine, said method comprising converting, with the catalyst of claim 1, NO to NO2 for oxidizing particulate matter when the gasoline engine is operated at a Lambda range above 1.01.

### Claim 17 (depends on 1)

A method for after treating an exhaust gas of gasoline engine, said method comprising contacting the exhaust gas with the catalyst of claim 1.

### Claim 18 (depends on 1)

A gasoline engine exhaust gas purification system, comprising the catalyst of claim 1, and a three-way convertor (TWC).