US 9,789,469 B2Granted

Exhaust gas-purifying catalyst and exhaust gas-purifying catalyst material

AssigneeCataler Corporation

InventorsSatoshi Matsueda, Akimasa Hirai, Kenichi Taki, Yuji Yabuzaki, Sho Hoshino

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Abstract

An exhaust gas-purifying catalyst material includes first oxide particles having an average particle diameter Dav of 1 μm to 95 μm and having an oxygen storage capacity, second oxide particles having an average particle diameter Dav of 0.05 μm to 0.5 μm, containing a metal element, and having no oxygen storage capacity, precious metal particles, and acidic oxide particles. The material has a correlation coefficient ρ of 0.45 or more obtained using first characteristic X-ray intensity for the metal element contained in the second oxide particle, second characteristic X-ray intensity for an element other than oxygen contained in the acidic oxide particle, and third characteristic X-ray intensity for a precious metal element contained in the precious metal particle.

An exhaust gas-purifying catalyst material comprising:

first oxide particles having an average particle diameter Dav of 1 μm to 95 μm and having an oxygen storage capacity;
second oxide particles having an average particle diameter Dav of 0.05 μm to 0.5 μm, containing a metal element, and having no oxygen storage capacity;
precious metal particles;
and
acidic oxide particles,
wherein the exhaust gas-purifying catalyst material has a correlation coefficient ρ of 0.45 or more, the correlation coefficient ρ being calculated from the following formula (1) using first characteristic X-ray intensity for the metal element contained in the second oxide particle, second characteristic X-ray intensity for an element other than oxygen contained in the acidic oxide particle, and third characteristic X-ray intensity for a precious metal element contained in the precious metal particle each obtained through characteristic X-ray measurement by energy dispersive X-ray spectroscopic method on a 500 nm-length straight section on the exhaust gas-purifying catalyst material:
ρ
=
C
⁡
(
SP
,
AC
/
PM
)
σ
⁡
(
SP
)
×
σ
⁡
(
AC
/
PM
)
(
1
)
wherein in the formula (1), the covariance C(SP,AC/PM), standard deviation σ(SP), and standard deviation σ(AC/PM) are calculated from to the following formulae (2), (3), and (4), respectively,
C
⁡
(
SP
,
AC
/
PM
)
=
1
n
⁢
∑
m
=
1
n
⁢
{
[
I
SP
⁡
(
m
)
-
I
SP
⁡
(
AV
)
]
×
[
I
AC
⁡
(
m
)
I
PM
⁡
(
m
)
-
I
AC
⁡
(
AV
)
I
PM
⁡
(
AV
)
]
}
(
2
)
σ
⁡
(
SP
)
=
1
n
⁢
∑
m
=
1
n
⁢
[
I
SP
⁡
(
m
)
-
I
SP
⁡
(
AV
)
]
2
(
3
)
σ
⁡
(
AC
/
PM
)
=
1
n
⁢
∑
m
=
1
n
⁢
[
I
AC
⁡
(
m
)
I
PM
⁡
(
m
)
-
I
AC
⁡
(
AV
)
I
PM
⁡
(
AV
)
]
2
(
4
)
in the formulae (2) to (4), ISP(m), IAC(m), and IPM (m) respectively represent the first characteristic X-ray intensity, the second characteristic X-ray intensity, and the third characteristic X-ray intensity each obtained for a m-th straight section among 25 straight sections arranged in line in the 500 nm-length straight section and each having a length of 20 nm;
ISP(Av), IAC(Av), and IPM(Av) respectively represent an average value of the first characteristic X-ray intensities, an average value of the second characteristic X-ray intensities, and an average value of the third characteristic X-ray intensities obtained for the 500 nm-length straight section;
and n is 25.

183 more elements

Facts

Application

15/434,627Filed 16 Feb 2017

Priority

JP 2016-03010019 Feb 2016

Published

US 2017/0239646 A124 Aug 2017

Granted

17 Oct 2017

Term ends

Not estimatedThe source records don’t support an estimate.

Classification27 codes

B01J 23/63
Platinum group metals: with rare earths or actinides
B01D 53/944
By catalytic processes: simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
B01D 53/945
Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]:…
B01J 23/002
Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00: mixed oxides other than spinels, e.g. perovskite

Abstract

Claims8