Catalyzed hydrocarbon trap material and method of making the same
US6074973A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1998 |
| Grant date | Jun 13, 2000 |
| Priority date | — |
| Expiry date | Mar 20, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S95/902
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A catalyzed hydrocarbon trap material washcoat (20) used in a trap (10), which may be placed downstream of a conventional catalyst member (28), is useful for treating internal combustion engine (22) exhaust. Trap (10) traps hydrocarbons during cold operation periods and releases them for oxidation during higher-temperature operating periods. The material comprises palladium and silver dispersed on a high surface area metal oxide support and a zeolite material such as one or more of ZSM-5, Beta, Y, and other suitable zeolites. The trap material is efficiently made by combining in a single vessel the zeolite, the metal oxide support, and aqueous solutions of a palladium compound and a silver compound. Surprisingly, the intimate combination of silver with the palladium does not adversely affect catalytic efficiency of the palladium and provides advantageous results in enhancing catalytic oxidation of hydrocarbons desorbed from the trap (10) and coke which forms thereon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.