Copper-silver zeolite catalysts
US5908806A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 1997 |
| Grant date | Jun 1, 1999 |
| Priority date | — |
| Expiry date | May 16, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A catalyst for the removal of carbon monoxide, hydrocarbons and nitrogen oxides in an exhaust gas made by a process comprising: PA1 a) preparing a suspension comprising a liquid, a zeolite, a weak base, and salts of copper and silver, PA2 said zeolite being crystalline and having a Si/Al atomic ratio between about 5 and about 100, a pore size between about 0.5 nm and about 1.3 nm, essentially no octahedral aluminum detectable by .sup.27 Al NMR spectroscopy and a sodium ion exchange capacity, with regard to total aluminum content, greater than 75%, and wherein said suspension contains sufficient amounts of said copper and silver salts to result in a copper content in said catalyst, when finished, between about 0.5 wt. % and about 12 wt. % and a silver content between about 0.25 wt. % and about 20 wt. %; PA1 b) adding a sufficient amount of a strong base to raise the pH of the suspension to between about 7 and about 9, thereby creating a metal-containing zeolite support in said suspension; PA1 c) separating the support from said liquid; PA1 d) dispersing said support on a substrate; and PA1 e) drying and calcining the product of step (d).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.