Pd-supporting Zr-based composite oxide

Patent metadata

Field	Value
Publication number	US-11084022-B2
Application number	US-201616061493-A
Country	US
Kind code	B2
Filing date	Dec 26, 2016
Priority date	Jan 28, 2016
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A Pd-supporting Zr-based composite oxide wherein by having a Zr-containing composite oxide support and Pd supported thereon and by showing, upon XAFS (X-ray absorption fine structure) analysis, a maximum peak in a Pd bond distance range of 2.500-3.500 Å, the maximum peak being located in a position of 3.050-3.110 Å.

First claim

The invention claimed is:

1. A Pd-supporting Zr-based composite oxide,
wherein Pd is supported on a Zr-containing composite oxide support, and
wherein the location of the maximum peak in a Pd bond distance range of 2.500 Å to 3.500 Å, is 3.050 Å to 3.110 Å, as determined by XAFS (X-Ray Absorption Fine Structure) analysis.

2. The Pd-supporting Zr-based composite oxide according to claim 1 ,
wherein the location of the maximum peak in a Pd bond distance range of 2.500 Å to 3.500 Å, is 3.060 Å to 3.100 Å, as determined by XAFS analysis.

3. The Pd-supporting Zr-based composite oxide according to claim 1 ,
wherein the Zr content in terms of ZrO 2 is 1 mass % or more and 90 mass % or less,
wherein the Ce content in terms of CeO 2 is 90 mass % or less, and
wherein the total of the Zr content in terms of ZrO 2 and the Ce content in terms of CeO 2 is 80 mass % or more,
the total mass of the exhaust gas purification catalyst being defined as 100 mass %.

4. The Pd-supporting Zr-based composite oxide according to claim 3 ,
wherein the Zr content in terms of ZrO 2 is 2 mass % or more and 85 mass % or less,
the total mass of the exhaust gas purification catalyst being defined as 100 mass %.

5. The Pd-supporting Zr-based composite oxide according to claim 3 ,
wherein the Ce content in terms of CeO 2 is 5 mass % or more and 80 mass % or less,
the total mass of the exhaust gas purification catalyst being defined as 100 mass %.

6. The Pd-supporting Zr-based composite oxide according to claim 1 ,
wherein the composite oxide support comprises a rare earth element (Ln) excluding Ce.

7. The Pd-supporting Zr-based composite oxide according to claim 6 ,
wherein the rare earth element (Ln) excluding Ce is one or more rare earth elements selected from among Y, La, Pr, Nd and Eu.

8. The Pd-supporting Zr-based composite oxide according to claim 6 ,
wherein the content of rare earth element (Ln) excluding Ce in terms of Ln 2 O 3 is 1 mass % or more and 20 mass % or less,
the total mass of the composite oxide support being defined as 100 mass %.

9. The Pd-supporting Zr-based composite oxide according to claim 1 wherein the Pd supporting mass in terms of Pd metal is 0.75 mass % or more and 3.0 mass % or less, with respect to the exhaust gas purification catalyst.

10. An exhaust gas purification catalyst, comprising the Pd-supporting Zr-based composite oxide according to claim 1 .

11. The exhaust gas purification catalyst according claim 10 ,
wherein the exhaust gas purification catalyst has a monolayer or multilayer structure onto a base material, and at least one of the layers is a coated layer of the Pd-supporting Zr-based composite oxide.

12. A method for producing the Pd-supporting Zr-based composite oxide according to claim 1 ,
wherein the method comprises the following steps in order:
a first step of heat treating an aqueous solution comprising a zirconium oxide precursor to form a Zr-containing sol,
a second step of adding a palladium precursor to the Zr-containing sol obtained in the first step to obtain a Pd-added Zr-containing sol,
a third step of contacting the Pd-added Zr-containing sol obtained in the second step with a basic compound to obtain a precipitate, and
a fourth step of firing the precipitate obtained in the third step.

13. The method according to claim 12 ,
wherein the zirconium oxide precursor is selected from zirconium nitrate, zirconium oxynitrate, zirconium sulfate and zirconium acetate.

14. The method according to claim 12 ,
wherein the Pd-added Zr-containing sol is contacted with a pore-forming agent which is a long-chain fatty acid, in combination with the basic compound to obtain a precipitate, in the third step.

Assignees

• Cataler Corp
• Santoku Corp

Inventors

• Murakami Kyosuke
• Narita Keiichi
• Matsueda Satoshi
• Tanaka Michio
• Murota Tadatoshi
• Ono Shigeru
• Tahara Tomonori

Classifications

• B01J2235/15

  X-ray diffraction · CPC title

• B01J35/393

  Metal or metal oxide crystallite size · CPC title

• B01J35/77

  Compounds characterised by their crystallite size · CPC title

• B01D2258/014

  Stoichiometric gasoline engines · CPC title

• B01D2255/908

  O2-storage component incorporated in the catalyst · CPC title