# US 9,433,927 B2 · Exhaust gas purification catalyst and exhaust gas purification method using said catalyst

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- Number: US 9,433,927 B2
- Document ID: US9433927B2
- Status: Granted
- Kind: B2
- Application number: 14/764,350
- Filed: 2014-01-31
- Published: 2015-12-24
- Granted: 2016-09-06
- Earliest claimed: 2013-01-31
- Assignees: Umicore Shokubai Japan Co., Ltd.
- Applicants: Umicore Shokubai Japan Co., Ltd.
- Inventors: Masanori Ikeda; Kazuyoshi Komata; Shigekazu Minami; Yuji Ogino; Hideki Goto
- Web page: https://patentgrep.com/patent/US9433927B2

## CPC

- B01J 23/63: with rare earths or actinides
- B01D 53/945: {characterised by a specific catalyst}
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 37/0036: {Grinding}
- B01J 37/0244: {Coatings comprising several layers}
- B01J 37/0248: {Coatings comprising impregnated particles}
- B01J 37/04: Mixing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/28: Phosphorising
- B01D 2255/1023: Palladium
- B01D 2255/1025: Rhodium
- B01D 2255/2061: Yttrium
- B01D 2255/2063: Lanthanum
- B01D 2255/40: Mixed oxides
- B01D 2255/407: Zr-Ce mixed oxides
- B01D 2255/9022: Two layers
- B01J 23/002: {Mixed oxides other than spinels, e.g. perovskite}
- B01J 35/30: characterised by their physical properties
- B01J 35/70: characterised by their crystalline properties, e.g. semi-crystalline (catalysts comprising carbon B01J21/18; molecular sieves B01J29/00)
- B01J 2235/00: Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- B01J 2523/00: Constitutive chemical elements of heterogeneous catalysts
- Y02T 10/12: Improving ICE efficiencies
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

As a way to suppress deterioration of catalytic performance in an exhaust gas purification catalyst even after being exposed to an exhaust gas containing a phosphorus compound, an exhaust gas purification catalyst is provided. The catalyst purifies an exhaust gas containing a phosphorus compound, and the catalyst includes a catalyst layer containing rhodium (Rh), palladium (Pd), and either a ceria-zirconia-lanthana complex oxide or a ceria-zirconia-lanthana-yttria complex oxide as catalyst active components. Further, an average value of distances between Rh particles and the nearest Pd particles of the Rh and the Pd is within 4000 nm, a weight ratio of the Pd to the Rh is from 0.2 to 4.9, and a content rate of yttria in the ceria-zirconia-lanthana-yttria complex oxide is 19% by weight or less.

## Claims

### Claim 1

An exhaust gas purification catalyst for purifying an exhaust gas containing a phosphorus compound, the catalyst comprising:
a catalyst layer A containing rhodium (Rh), palladium (Pd), and either a ceria-zirconia-lanthana complex oxide or a ceria-zirconia-lanthana-yttria complex oxide as catalyst active components,
wherein an average value of distances between Rh particles and the nearest Pd particles of the Rh and the Pd is within 4000 nm,
a weight ratio of the Pd to the Rh is from 0.2 to 4.9, and
a content rate of yttria in the ceria-zirconia-lanthana-yttria complex oxide is 19% by weight or less.

### Claim 2 (depends on 1)

The exhaust gas purification catalyst according to claim 1, further comprising lanthanum-containing alumina.

### Claim 3 (depends on 1)

The exhaust gas purification catalyst according to claim 1, further comprising:
a catalyst layer B,
wherein the catalyst layer B comprises at least one novel metal selected from the group consisting of rhodium and palladium as an essential component, which is formed by coating as a lower layer, and the catalyst layer A is formed by coating as a surface layer.

### Claim 4 (depends on 3)

The exhaust gas purification catalyst according to claim 3, wherein the catalyst layer B further comprises CeO2—ZrO2 complex oxide and a lanthanum containing alumina.

### Claim 5 (depends on 1)

The exhaust gas purification catalyst according to claim 1, comprising a phosphorus compound.

### Claim 6 (depends on 5)

The exhaust gas purification catalyst according to claim 5, wherein a cross-section at a detection portion in 0 to 10% of the maximum intensity of phosphorus Kα ray in EPMA (electron probe microanalyzer) analysis is larger than a cross-section at a detection portion in 10 to 54% thereof.

### Claim 7 (depends on 1)

The exhaust gas purification catalyst according to claim 1,
wherein the catalyst active components are supported on a three-dimensional structure, and
the phosphorus compound is contained as phosphorus oxide in an amount of 1 to 50 g per 1 L of the three-dimensional structure.

### Claim 8 (depends on 1)

A method of purifying an exhaust gas, the method comprising purifying an exhaust gas using the exhaust gas purification catalyst according to claim 1.