Ceria-zirconia-based composite oxide and method for producing same, and exhaust gas purification catalyst including ceria-zirconia-based composite oxide

Patent metadata

Field	Value
Publication number	US-10913051-B2
Application number	US-201815974060-A
Country	US
Kind code	B2
Filing date	May 8, 2018
Priority date	Aug 9, 2013
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

A ceria-zirconia-based composite oxide containing a composite oxide of ceria and zirconia is provided, in which primary particles having a particle diameter of 1.5 to 4.5 μm account for, on a particle number basis, at least 50% of all primary particles in the ceria-zirconia-based composite oxide, and the molar ratio of cerium to zirconium in the ceria-zirconia-based composite oxide is between 43:57 and 55:45.

First claim

What is claimed is:

1. A ceria-zirconia-based composite oxide comprising a composite oxide containing ceria and zirconia, wherein
primary particles having a particle diameter of 1.5 to 4.5 μm in the ceria-zirconia-based composite oxide account for, on a particle number basis, at least 50% of all primary particles in the composite oxide;
primary particles having a particle diameter of less than 1.5 μm in the ceria-zirconia-based composite oxide account for, on a particle number basis, at least 4.4% of all primary particles in the composite oxide;
a content ratio of cerium to zirconium in the ceria-zirconia-based composite oxide is in a range of 50:50 to 55:45 by mole ratio; and
when heated for 5 hours in the atmosphere under a temperature condition of 1,100° C. and thereafter examined by X-ray diffractometry using CuKα, the ceria-zirconia-based composite oxide exhibits an X-ray diffraction pattern in which an intensity ratio of diffraction line at a 2θ of 14.5° to diffraction line at a 2θ of 29° {I(14/29) value} and an intensity ratio of diffraction line at a 2θ of 28.5° to diffraction line at a 2θ of 29° {I(28/29) value} satisfy requirement I(14/29)≤0.015 and I(28/29)≤0.08.

2. The ceria-zirconia-based composite oxide according to claim 1 , wherein primary particles having a particle diameter of less than 1.5 μm in the ceria-zirconia-based composite oxide account for, on a particle number basis, not more than 40% of all primary particles in the composite oxide.

3. The ceria-zirconia-based composite oxide according to claim 1 , wherein primary particles having a particle diameter of less than 1.5 μm in the ceria-zirconia-based composite oxide account for, on a particle number basis, not more than 20% of all primary particles in the composite oxide.

4. The ceria-zirconia-based composite oxide according to claim 1 , wherein primary particles having a particle diameter of less than 1.5 μm in the ceria-zirconia-based composite oxide account for, on a particle number basis, not more than 10% of all primary particles in the composite oxide.

5. The ceria-zirconia-based composite oxide according to claim 1 , wherein primary particles having a particle diameter of 1.5 to 4.5 μm in the ceria-zirconia-based composite oxide account for, on a particle number basis, at least 70% of all primary particles in the composite oxide.

6. The ceria-zirconia-based composite oxide according to claim 1 , wherein primary particles having a particle diameter of 1.5 to 4.5 μm in the ceria-zirconia-based composite oxide account for, on a particle number basis, at least 80% of all primary particles in the composite oxide.

7. An exhaust gas purification catalyst comprising the ceria-zirconia-based composite oxide according to claim 1 .

Assignees

• Toyota Motor Co Ltd
• Cataler Corp

Inventors

• Morikawa Akira
• Konishi Kae
• Tanabe Toshitaka
• Suda Akihiko
• Miura Masahide
• Chinzei Isao
• Suzuki Hiromasa
• Chiba Akiya
• Iizuka Kosuke

Classifications

• B01J35/77

  Compounds characterised by their crystallite size · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J35/70

  characterised by their crystalline properties, e.g. semi-crystalline (catalysts comprising carbon B01J21/18; molecular sieves B01J29/00) · CPC title

• B01J2235/15

  X-ray diffraction · CPC title

• B01J35/40

  characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77) · CPC title