US 2021/0277814 A1 · EXHAUST GAS PURIFICATION CATALYST

Abstract

An exhaust gas purification catalyst including an alkaline-earth metal carried on a porous carrier in a highly dispersed state. The catalyst layer of the exhaust gas purification catalyst has an alkaline-earth metal carrying region including a porous carrier, Pt, and a sulfuric acid salt of at least one alkaline-earth metal carried on the porous carrier, wherein a value of RAe/Pt is 0.5 or more, where RAe/Pt represents the Pearson's correlation coefficient calculated using α and β in each pixel obtained by, for a cross section of the region, performing the area analysis by FE-EPMA under the conditions of: pixel size 0.34 μm×0.34 μm; and number of measured pixels 256×256; and measuring an intensity (α: cps) of a characteristic X ray of an element (Ae) of the alkaline-earth metal and an intensity (β: cps) of a characteristic X ray of Pt for each pixel.

Claims8

Dependent claims

An exhaust gas purification catalyst which is configured to be arranged in an exhaust pipe of an internal combustion engine and configured to purify an exhaust gas exhausted from the internal combustion engine, comprising:

a base material;
and
a catalyst layer formed on the base material,
the catalyst layer having an alkaline-earth metal carrying region including,
a porous carrier constituted of an inorganic compound,
Pt carried on the porous carrier, and
a sulfuric acid salt of at least one alkaline-earth metal carried on the porous carrier, wherein
a value of RAe/Pt is 0.5 or more,
where RAe/Pt represents a Pearson's correlation coefficient, the Pearson's correlation coefficient being determined by performing an area analysis of a cross section of the alkaline-earth metal carrying region of the catalyst layer by FE-EPMA under a condition of:
pixel size 0.34 μm×0.34 μm;
and
number of measured pixels 256×256;
and measuring an intensity (α:
cps) of a characteristic X ray of an element (Ae) of the alkaline-earth metal and an intensity (β:
cps) of a characteristic X ray of Pt for each pixel,
to measure the Pearson's correlation coefficient using α and β in each pixel.

13 more elements

A method for manufacturing an exhaust gas purification catalyst which is configured to be arranged in an exhaust pipe of an internal combustion engine and configured to purify exhaust gas exhausted from the internal combustion engine, the method comprising the steps of:

forming, on a base material, a catalyst layer having, at at least one part thereof, an alkaline-earth metal carrying region which includes:
a porous carrier constituted of an inorganic compound,
Pt carried on the porous carrier, and
a sulfuric acid salt of at least one alkaline-earth metal carried on the porous carrier;
and
firing the base material which has the catalyst layer formed thereon, wherein
the formation step of the catalyst layer includes:
mixing the following components:
an inorganic compound particle forming the porous carrier;
a Pt particle or a precursor for precipitating Pt;
a water-soluble compound of the alkaline-earth metal;
and
a S-containing water-soluble organic compound containing S as a constituent element, and capable of forming the sulfuric acid salt of the alkaline-earth metal;
with an aqueous solvent, to prepare a raw material suspension,
drying and further firing the raw material suspension, thereby preparing a powder material including the porous carrier, Pt, and the sulfuric acid salt of the alkaline-earth metal mixed therein,
preparing a slurry for forming an alkaline-earth metal carrying region, including at least the powder material and an aqueous solvent, and
forming the alkaline-earth metal carrying region on the base material using the slurry.

14 more elements

Dependencies are inferred from the claim text.

Exhaust gas purification catalyst

Life of this patent

Exhaust gas purification catalyst

Life of this patent

Abstract

Claims8