Catalyst for purifying exhaust gases
US5948376A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 14, 1996 |
| Grant date | Sep 7, 1999 |
| Priority date | — |
| Expiry date | Mar 14, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A catalyst for purifying exhaust gases includes a porous support, an NO.sub.x storage component including at least one member selected from the group consisting of alkaline-earth metals, rare-earth elements and alkali metals, and loaded on the porous support, a noble metal catalyst ingredient loaded on the porous support, and disposed adjacent to the NO.sub.x storage component, and ceria (CeO.sub.2) disposed away from the noble metal catalyst ingredient. By disposing the noble metal catalyst ingredient adjacent to the NO.sub.x storage component, the reduction reactions of NO.sub.x can be facilitated in fuel-rich (i.e., oxygen-lean) atmospheres without being interfered by the ceria. By disposing the ceria away from the noble metal catalyst ingredient, oxygen, which has been stored thereon in fuel-lean (i.e., oxygen-rich) atmospheres, can be released from the ceria at a controlled rate in a controlled amount in fuel-rich (i.e., oxygen-lean) atmospheres, and thereby the released oxygen can be inhibited from reacting with HC and CO in fuel-rich (i.e., oxygen-lean) atmospheres. Thus, the catalyst is improved in terms of NO.sub.x purifying performance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.