Ceria-zirconia composite oxide, method for producing the same, and catalyst for purifying exhaust gas using the ceria-zirconia composite oxide
US10112180B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Oct 2, 2014 |
| Grant date | Oct 30, 2018 |
| Priority date | — |
| Expiry date | Oct 2, 2034 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A ceria-zirconia composite oxide includes at least one of lanthanum, yttrium, and praseodymium. A rate of a total content of the at least one rare earth element to a total content of cerium and zirconium is 0.1 at % to 4.0 at %. A content of the rare earth element present in near-surface regions, which are at a distance of less than 50 nm from surfaces of primary particles of the ceria-zirconia composite oxide, accounts for 90 at % or more of the total content of the rare earth element. An average particle size of the primary particles of the ceria-zirconia composite oxide is 2.2 μm to 4.5 μm. After a predetermined durability test, the intensity ratio I(14/29) of a diffraction line at 2θ=14.5° to a diffraction line at 2θ=29° and the intensity ratio I(28/29) of a diffraction line at 2θ=28.5° to the diffraction line at 2θ=29° respectively satisfy the following conditions: I(14/29)≥0.02, andI(28/29)≤0.08.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.