# US 8,771,624 B2 · Catalyst for purifying exhaust gas from internal combustion engine and process for purifying exhaust gas using the same

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- Number: US 8,771,624 B2
- Document ID: US8771624B2
- Status: Granted
- Kind: B2
- Application number: 12/922,708
- Filed: 2009-03-13
- Published: 2011-02-03
- Granted: 2014-07-08
- Earliest claimed: 2008-03-19
- Assignees: Umicore Shokubai Japan Co., Ltd.; Umicore Shokubai USA Inc.
- Applicants: Masanori Ikeda; Hideki Goto; Kosuke Mikita
- Inventors: Masanori Ikeda; Hideki Goto; Kosuke Mikita
- Web page: https://patentgrep.com/patent/US8771624B2

## CPC

- B01J 23/58: with alkali- or alkaline earth metals
- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01J 23/44: Palladium
- B01J 23/63: with rare earths or actinides
- B01D 2255/1023: Palladium
- B01D 2255/1025: Rhodium
- B01D 2255/2047: Magnesium
- B01D 2255/407: Zr-Ce mixed oxides
- B01D 2258/014: Stoichiometric gasoline engines
- B01J 37/0036: {Grinding}
- B01J 37/0215: {Coating}
- F01N 3/28: Construction of catalytic reactors
- 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)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)

## Abstract

An Object of the patent is to remove highly reducing hydrocarbon exhausted during acceleration period, and to remove efficiently hydrocarbon even after contacting with highly reducing hydrocarbon. By using a catalyst having a higher proportion of palladium having surface charge of 2-valence or 4-valence supported than that of 0-valence by supporting palladium together with magnesium oxide, hydrocarbon exhausted from an internal combustion engine especially during acceleration period can be efficiently removed.

## Claims

### Claim 1

A catalyst for treating an exhaust gas from an internal combustion engine, which comprises a catalyst active component comprising at least both palladium and magnesium, wherein said palladium includes palladium that has a surface charge of 2-valence, 4-valence, or both, and the proportion of the palladium that has a surface charge of 0-valence is less than 0.5, said proportion being calculated by 0-valence/(0-valence+2-valence+4-valence), and said catalyst active component is supported on a refractory inorganic oxide powder that comprises activated alumina, zeolite, titania, zirconia, silicon oxide, or a composite oxide thereof and, optionally, further comprises a rare-earth metal other than cerium.

### Claim 2 (depends on 1)

The catalyst according to claim 1, wherein said catalyst active component is supported on a three-dimensional structure.

### Claim 3 (depends on 2)

The catalyst according to claim 2, wherein the amounts of palladium (in terms of Pd) and magnesium (in terms of MgO) supported on 1 L of the three-dimensional structure are 0.05 to 20 g and 0.1 to 40 g, respectively.

### Claim 4 (depends on 3)

The catalyst according to claim 3, further comprising platinum and/or rhodium.

### Claim 5 (depends on 2)

The catalyst according to claim 2, further comprising platinum and/or rhodium.

### Claim 6 (depends on 1)

The catalyst according to claim 1, further comprising platinum and/or rhodium.

### Claim 7 (depends on 6)

The catalyst according to claim 6, wherein the amount of platinum supported on 1 L of the three-dimensional structure is 10 g or less, and the amount of rhodium supported on 1 L of the three-dimensional structure is 5 g or less.

### Claim 8 (depends on 1)

The catalyst according to claim 1, wherein the amount of refractory inorganic oxide powder supported on 1 L of the three-dimensional structure is 10 to 300 g.

### Claim 9 (depends on 1)

The catalyst according to claim 1, further comprising cerium oxide and/or ceria-zirconia composite oxide.

### Claim 10 (depends on 1)

A process for purifying an exhaust gas, which comprises treating hydrocarbon in the exhaust gas from an internal combustion engine including a reducing gas in the presence of the catalyst as set forth in claim 1.

### Claim 11 (depends on 1)

A process for removing hydrocarbon, which comprises treating an exhaust gas having an A/F ratio less than 14.7 from an internal combustion engine in the presence of the catalyst as set forth in claim 1.

### Claim 12 (depends on 11)

The process according to claim 11, wherein an exhaust gas emitted from an internal combustion engine in an acceleration state is treated.

### Claim 13 (depends on 12)

The process according to claim 12, wherein an acceleration speed in the acceleration state is less than 10 km/s2.

### Claim 14 (depends on 13)

The process according to claim 13, wherein a speed in the acceleration state is less than 300 km/h.