Catalyst for automotive emission control and method for making same
US4152301A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1978 |
| Grant date | May 1, 1979 |
| Priority date | — |
| Expiry date | Jun 8, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A layered catalyst having significantly improved performance characteristics including greater resistance to poisoning and sintering in automotive exhaust comprising an alumina support having a first layer of platinum positioned at the support surface and penetrating the body thereof to a desired depth with a second layer of at least one of the catalytically active materials selected from the group consisting of rhodium and palladium, the second layer being adjacent to the first layer and penetrating the body of the support for a depth beyond that of the first layer, maximum concentration of platinum being in the first layer together with minimum concentration of the catalytically active materials, and minimum concentration of platinum with maximum concentration of the catalytically active materials being in the second layer. The catalyst is prepared by impregnation with separate solutions of the catalyst materials, acid treatment of the active sites of the support being used to block the sites from the surface through the desired depth of the platinum layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.