Catalyst for treatment of exhaust gases from internal combustion engines
US4919902A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 1988 |
| Grant date | Apr 24, 1990 |
| Priority date | — |
| Expiry date | Nov 9, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
This invention relates to a catalytic composite for treating an exhaust gas comprising a support which is a refractory inorganic oxide having dispersed thereon lanthanum, at least one other rare earth component and at least one noble metal component selected from the group consisting of platinum, palladium, rhodium, ruthenium and iridium. An essential feature of said catalytic composite is that the lanthanum be present as crystalline particles of lanthanum oxide which have an average crystallite size of less than about 25 Angstroms. The support may be selected from the group consisting of alumina, silica, titania, zirconia, aluminosilicates and mixtures thereof with alumina being preferred. Illustrative of the other rare earth components are cerium, neodymium, praeseodymium, dysprosium, europium, holmium and ytterbium. An important feature in manufacturing the catalytic composite is the dispersion of lanthanum oxide onto said refractory inorganic oxide support. In a specific example, lanthanum may be dispersed on alumina as follows. A solution of a lanthanum salt is mixed with a hydrosol of aluminum, particles are formed from said lanthanum containing hydrosol, calcined to form an …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.