# US 2025/0205641 A1 · N2o decomposition catalyst

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- Number: US 2025/0205641 A1
- Document ID: US20250205641A1
- Status: Published application
- Kind: A1
- Application number: 18/847,436
- Filed: 2023-03-27
- Published: 2025-06-26
- Earliest claimed: 2022-03-29
- Assignees: Mitsubishi Heavy Industries, Ltd.
- Applicants: Mitsubishi Heavy Industries, Ltd.
- Inventors: Tomotsugu Masuda; Keiichiro Kai; Shimpei Kaneda; Masanao Yonemura
- Web page: https://patentgrep.com/patent/US20250205641A1

## CPC

- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01J 29/76: Iron group metals or copper
- B01D 53/8628: {Processes characterised by a specific catalyst}
- B01D 53/9427: {for removing nitrous oxide}
- B01J 23/745: Iron
- B01J 29/46: Iron group metals or copper
- B01D 2251/2062: Ammonia
- B01D 2255/20738: Iron
- B01D 2255/20746: Cobalt
- B01D 2255/30: Silica
- B01D 2255/50: Zeolites
- B01D 2255/9202: Linear dimensions
- B01D 2257/402: Dinitrogen oxide
- B01D 2258/01: Engine exhaust gases
- B01D 2258/012: Diesel engines and lean burn gasoline engines
- F02D 19/0644: {the gaseous fuel being hydrogen, ammonia or carbon monoxide}
- Y02C 20/10: of nitrous oxide (N2O)
- 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)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]

## Abstract

Provided are: a catalyst containing a carrier including SiO2 and Al2O3 and an iron element carried on the carrier, having a total amount of desorbed pyridine of 100 μmol or more with respect to 1 g catalyst within the range of 150° C. inclusive to 450° C. exclusive in the TPD spectrum, and configured to promote the decomposition reaction of nitrogen monoxide and nitric monoxide; and a method of reducing nitrogen monoxide and nitric monoxide in a gas containing water and/or a sulfur oxide, nitrogen monoxide, and nitric monoxide, the method comprising bringing a gas and a reductant into contact with the catalyst to decompose nitrogen monoxide and nitric monoxide, the gas containing water and/or a sulfur oxide, nitrogen monoxide, and nitric monoxide.

## Claims

### Claim 1

A catalyst comprising:
a support containing SiO2 and Al2O3; and
an iron element supported on the support,
wherein in a TPD spectrum, a total amount of pyridine desorbed in a range of 150° C. or higher and lower than 450° C. is 100 μmol or more per 1 g of the catalyst, and
the catalyst is configured to promote a decomposition reaction of nitrous oxide or a decomposition reaction of nitrous oxide and nitric oxide.

### Claim 2

A catalyst comprising:
a support containing SiO2 and Al2O3; and
an iron element supported on the support,
wherein in a TPD spectrum, a ratio of a pyridine desorption amount at a peak top present in a range of 150° C. or higher and lower than 450° C. to a pyridine desorption amount at a peak top present in a range of 450° C. or higher and 800° C. or lower is more than 1, and
the catalyst is configured to promote a decomposition reaction of nitrous oxide or a decomposition reaction of nitrous oxide and nitric oxide.

### Claim 3

A catalyst comprising:
a support containing SiO2 and Al2O3; and
an iron element supported on the support,
wherein in a TPD spectrum, a ratio of a total amount of pyridine desorbed in a range of 150° C. or higher and lower than 450° C. to a total amount of pyridine desorbed in a range of 450° C. or higher and 800° C. or lower is 0.9 or more, and
the catalyst is configured to promote a decomposition reaction of nitrous oxide or a decomposition reaction of nitrous oxide and nitric oxide.

### Claim 4

A catalyst comprising:
a support containing SiO2 and Al2O3; and
an iron element supported on the support,
wherein in a TPD spectrum, a temperature at a peak top in a range of 450° C. or higher and 800° C. or lower is 490° C. or higher and 650° C. or lower, and
the catalyst is configured to promote a decomposition reaction of nitrous oxide or a decomposition reaction of nitrous oxide and nitric oxide.

### Claim 5

A catalyst comprising:
a support containing SiO2 and Al2O3; and
an iron element supported on the support,
wherein a saturated adsorption amount of pyridine is 100 μmol or more per 1 g of the catalyst, and
the catalyst is configured to promote a decomposition reaction of nitrous oxide or a decomposition reaction of nitrous oxide and nitric oxide.

### Claim 6

A catalyst comprising:
a support containing SiO2 and Al2O3; and
an iron element supported on the support,
wherein a crystallite size is 20 nm or more, and
the catalyst is configured to promote a decomposition reaction of nitrous oxide or a decomposition reaction of nitrous oxide and nitric oxide.

### Claim 7

A catalyst comprising:
an organic structure-directing agent (OSDA)-free zeolite; and
an iron element supported on the organic structure-directing agent (OSDA)-free zeolite,
the catalyst is configured to promote a decomposition reaction of nitrous oxide or a decomposition reaction of nitrous oxide and nitric oxide.

### Claim 8 (depends on 1)

The catalyst according to claim 1,
wherein even after being exposed to gas containing 20% of H2O and 20 ppm of SO2 at 530° C. for 70 hours, a NO2 decomposition rate is 60% or more and NO decomposition rate is 90% or more under a condition of 450° C.

### Claim 9 (depends on 1)

A catalyst element comprising:
a substrate; and
the catalyst according to claim 1 that covers the substrate.

### Claim 10 (depends on 1)

A method of reducing nitrous oxide or nitrous oxide and nitric oxide from gas containing at least one selected from water and sulfur oxide and nitrous oxide or from gas containing at least one selected from water and sulfur oxide, nitrous oxide, and nitric oxide, the method comprising:
bringing the gas containing at least one selected from water and sulfur oxide and nitrous oxide or the gas containing at least one selected from water and sulfur oxide, nitrous oxide, and nitric oxide and a reducing agent into contact with the catalyst according to claim 1 to decompose nitrous oxide or nitrous oxide and nitric oxide.

### Claim 11 (depends on 10)

The method according to claim 10,
wherein in the gas, a content of the water is 10% or more and a content of the sulfur oxide is 15 ppm or more.

### Claim 12 (depends on 1)

An exhaust gas treatment device comprising:
a reactor that accommodates the catalyst according to claim 1;
a first supply line that is configured such that gas to be treated flows into the reactor;
a second supply line that is configured such that a reducing agent flows into the reactor; and
an exhaust line that is configured such that gas flows out from the reactor,
wherein the gas to be treated is gas containing at least one selected from water and sulfur oxide and nitrous oxide or gas containing at least one selected from water and sulfur oxide, nitrous oxide, and nitric oxide.

### Claim 13 (depends on 12)

The exhaust gas treatment device according to claim 12,
wherein in the gas to be treated, a content of the water is 10% or more and a content of the sulfur oxide is 15 ppm or more.

### Claim 14 (depends on 12)

An ammonia fuel engine comprising the exhaust gas treatment device according to claim 12.