Catalyst compositions for the treatment of vehicular exhaust gases comprise zirconium oxide and cerium oxide, and have a high reducibility and a stable specific surface area
US8158551B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 2007 |
| Grant date | Apr 17, 2012 |
| Priority date | — |
| Expiry date | Mar 28, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Catalyst compositions for the treatment of vehicular exhaust gases are based on zirconium and cerium oxides, have a cerium oxide content of at most 50% by weight, a level of reducibility of at least 95% after calcination in air at 600°, and a specific surface area after calcination for 4 hours at 1100° of at least 15 m2/g; such compositions are prepared by forming an aqueous mixture containing zirconium and cerium compounds, by heating this mixture to at least 100° and, after the heating, adjusting it to a basic pH, by adding a surfactant additive to the precipitate obtained from this mixture and by calcinating the precipitate in an inert gas or under vacuum at a temperature of at least 900° and then in an oxidizing atmosphere at a temperature of at least 600°.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.