Catalyst supports having promoter oxide gradient, resulting catalyst and method of making the supports
US5102850A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1990 |
| Grant date | Apr 7, 1992 |
| Priority date | — |
| Expiry date | Oct 17, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Catalysts which are suitable for auto exhaust use are made with a promoter oxide that is deposited in a concentration gradient. A solution of the promoter oxide precursor, e.g., cerous nitrate solution, is impreganted uniformly into the pore structure of a support which can be in the form of beads or extrudates to a level just below the full incipient wetness. The impregnated support is then treated with a gaseous base such as ammonia, under dynamic conditions such as tumbling (to insure uniformity), which causes the precipitation of the promoter oxide in the form of a radial concentration gradient. The resulting product is then dried and calcined at sufficiently high temperature to effect complete conversion of the promoter precursor to its oxide form, e.g., CeO.sub.2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.