US5326735A
Expired / Lapsed
US
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Iridium catalysts for purifying exhaust gas
Assignee: NE Chemcat Corp
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Filing: 1992-09-30
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Granted: 1994-07-05
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Expires: 2012-09-30
Abstract
Abstract A catalyst comprising an iridium supported on at least one carrier selected from the group consisting of metal carbides and metal nitrides for eliminating nitrogen oxides in exhaust gas in the presence of oxygen in excess of the stoichiometric quantity of oxidizing components for reducing components. The catalyst is effective for eliminating NO x in exhaust gas from lean burn engines such as lean burn gasoline engines and diesel engines containing excess O 2 corresponding to an A/F ratio of 17 or over.
Inventors
- 👤 Takashi Itoh
- 👤 Yukio Kosaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:17
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/945; B01D53/9404; B01D53/9409; B01D53/9413; B01D53/9418; B01J; B01J23/00; B01J23/38; B01J23/40; B01J23/46; B01J23/468; B01J27/00; B01J27/20; B01J27/22; B01J27/24; B01D2255/00; B01D2255/10; B01D2255/102; B01D2255/1028; B01D2255/20; B01D2255/207; B01D2255/20707; B01D2255/90; B01D2255/92; B01D2255/9207; B01D2258/00; B01D2258/01; B01D2258/012; F; F02; F02B; F02B1/00; F02B1/02; F02B1/04; F02B3/00; F02B3/06; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
58 words
A catalyst for purifying exhaust gas, consisting essentially of an iridium with crystallite diameter of 2 to 100 nm supported on one carrier selected from the group consisting of metal carbides and metal nitrides, wherein the supported amount of said iridium is 0.005 to 10.0% by weight based on the total amount of the iridium and the carrier.
Claim 2
Dependent Claim
58 words
A catalyst for purifying exhaust gas, consisting essentially of an iridium with crystallite diameter of 2 to 100 nm supported on one carrier selected from the group consisting of metal carbides and metal nitrides, wherein the supported amount of said iridium is 0.005 to 10.0% by weight based on the total amount of the iridium and the carrier.
Claim 3
Dependent Claim
38 words
The catalyst as claimed in claim 1, wherein said carrier comprises at least one member selected from the group consisting of silicon carbide, titanium carbide, boron carbide, vanadium carbide, tantalum carbide, titanium nitride, chromium nitride, and zirconium nitride.
Claim 4
Dependent Claim
28 words
The catalyst as claimed in claim 2, wherein said carrier comprises at least one member selected from the group consisting of silicon carbide, titanium carbide, and titanium nitride.
Claim 5
Dependent Claim
29 words
The catalyst as claimed in claim 1, wherein said carrier is in the form of whisker or powder having a particle diameter of about 0.1 to about 100 μm.
Claim 6
Dependent Claim
34 words
The catalyst as claimed in claim 1, wherein said carrier has a BET specific surface area of 20 m 2 /g or less and a pore volume of 0.5 cm 3 /g or less.
Claim 7
Dependent Claim
36 words
The catalyst as claimed in claim 1, wherein said iridium is in the state of the metal or an oxide selected from the group consisting of IrO, Ir 2 O 3 , and IrO 2 .
Claim 8
Dependent Claim
19 words
The catalyst as claimed in claim 1, wherein said iridium has a crystallite diameter of 5 to 20 nm.
Claim 9
Dependent Claim
26 words
A catalyst as claimed in claim 1, wherein said catalyst is in the form of a shaped product or is coated on a refractory support substrate.
References Cited (Backward Citations)
FR2201711A5
Cited
US3953363A
Cited
US4039622A
Cited
US4492770A
Cited
US4372933A
Cited
GB2163364A
Cited
EP0399891A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-07-04 | 1998-01-03 | 1998-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-07-04 | 2002-01-03 | 2002-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-07-04 | 2006-01-03 | 2006-07-05 | $7700.00 | Window Closed / Lapsed |