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Catalyst for exhaust gas purification

An exhaust gas purification and catalyst technology, which is applied in the directions of physical/chemical process catalysts, catalyst activation/preparation, heterogeneous catalyst chemical elements, etc., and can solve the problems of catalyst activity reduction and grain growth, etc.

Inactive Publication Date: 2005-09-07
DAIHATSU MOTOR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, in the above composite oxide, when the general formula ABO 3 In the perovskite-type lattice structure shown, a divalent element such as Sr (strontium) or Ba (barium) is placed on the A site, and when Co (cobalt) is placed on the B site, Rh is difficult to stabilize in a redox atmosphere. It exists in the perovskite lattice structure, due to long-term use, the grain grows, and sometimes the catalyst activity is greatly reduced

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0077] Lanthanum methoxypropoxide [La(OCHMeCH 2 OMe)3 ]40.6g (0.100 mol) and iron methoxypropoxide [Fe(OCHMeCH 2 OMe) 3 ] 30.7 g (0.095 mol) was added to a 500-ml round bottom flask, 200 mL of toluene was added and stirred to dissolve it to prepare a mixed alkoxide solution. And, the rhodium acetylacetonate [Rh(CH 3 COCHCOCH 3 ) 3 ] 2.00 g (0.005 mol) was dissolved in 200 mL of toluene, and the solution was added to the mixed alkoxide solution in a round bottom flask to prepare a uniform mixed solution containing LaFeRh.

[0078] Then, 200 mL of deionized water was dropped into the round bottom flask over about 15 minutes. This hydrolysis produces a brown viscous precipitate.

[0079] After that, it was stirred at room temperature for 2 hours, and then toluene and water were distilled off under reduced pressure to obtain a LaFeRh composite oxide precursor. Then, the precursor was transferred to a shallow bottom plate, and after ventilating and drying at 60°C for 24 hours, it was h...

Embodiment 2

[0082] Lanthanum methoxypropoxide [La(OCHMeCH 2 OMe) 3 ] 28.4g (0.070 mol), praseodymium methoxypropoxide [Pr(OCHMeCH 2 OMe) 3 ] 12.2g (0.030 mol), iron methoxypropoxide [Fe(OCHMeCH 2 OMe) 3 ] 30.7 g (0.095 mol) was added to a 500-ml round bottom flask, 200 mL of toluene was added, and stirred to dissolve, thereby preparing a mixed alkoxide solution. And, the rhodium acetylacetonate [Rh(CH 3 COCHCOCH 3 ) 3 ] 2.00 g (0.005 mol) was dissolved in 200 mL of toluene, and the solution was added to the mixed alkoxide solution in a round bottom flask to prepare a uniform mixed solution containing LaPrFeRh.

[0083] Then, the same operation as in Example 1 was used to obtain a dark brown powder.

[0084] The powder was measured by powder X-ray diffraction, and the result showed that the powder was La 0.70 Pr 0.30 Fe 0.95 Rh 0.05 O 3 A single crystalline phase composed of complex oxides with a perovskite-type lattice structure. In addition, its specific surface area is 30m 2 / g, the Rh cont...

Embodiment 3

[0108] Lanthanum methoxypropoxide [La(OCHMeCH 2 OMe) 3 ]32.5g (0.080mol), neodymium methoxypropoxide [Nd(OCHMeCH 2 OMe) 3 ]6.2g (0.015mol), cerium methoxypropoxide [Ce(OCHMeCH 2 OMe) 3 ]2.0g (0.005 mol), iron methoxypropoxide [Fe(OCHMeCH 2 OMe) 3 ] 19.4g (0.060 mol), manganese methoxypropoxide [Mn(OCHMeCH 2 OMe) 2 ] 11.3 g (0.035 mol) was added to a 500-ml round bottom flask, 200 mL of toluene was added, and stirred to dissolve, thereby preparing a mixed alkoxide solution.

[0109] Then, 11.5 g (equivalent to 0.51 g, 0.005 mol in terms of Rh) of a rhodium nitrate aqueous solution (Rh portion 4.478 mass%) diluted with 150 mL of deionized water was dropped into the round bottom flask over about 15 minutes. This hydrolysis produces a dark brown viscous precipitate.

[0110] Next, the same operation as in Example 1 was used to obtain a dark brown powder. It should be noted that the heat treatment was performed at 850°C for 2 hours.

[0111] The powder was measured by powder X-ray diffra...

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Abstract

To provide an exhaust gas purifying catalyst which can maintain the catalytic activity of Rh at a high level over a long time and can achieve satisfactory emission control performance, an exhaust gas purifying catalyst is prepared so as to contain a composite oxide having a perovskite structure represented by the general formula (1): ABRhO3 wherein A represents at least one element selected from rare-earth elements essentially including one or more rare-earth elements each having a valence of 3 as the only valence and arbitrarily including Ce and / or Pr; and B represents at least one element selected from transition elements excluding Co, Rh and the rare-earth elements, and Al.

Description

Technical field [0001] The present invention relates to an exhaust gas purification catalyst that effectively purifies carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in exhaust gases such as automobile engines. Background technique [0002] So far, as a three-way catalyst that can simultaneously purify carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) contained in exhaust gas, Pt (platinum), Rh (rhodium), Noble metals such as Pd (palladium). [0003] Among these noble metals, it is known that Rh can reduce NOx best. For example, the general formula ABO 3 The shown composite oxide of the perovskite type lattice structure is impregnated and supported with Rh, and the heat resistance can be improved. It is also known that if Rh is included as the composition of the composite oxide, the heat resistance and exhaust gas purification performance can be further improved compared to impregnating and supporting Rh. [0004] As mentioned above, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/86B01D53/94B01J21/04B01J21/06B01J23/00B01J23/63B01J23/656B01J23/68B01J23/89B01J35/00B01J37/02B01J37/03B01J37/08C01G55/00
CPCB01J23/688B01J23/6562B01J23/63B01J21/04B01J23/8946B01J37/08B01D53/945B01J23/002B01D2255/402C01P2002/54B01D2255/1025Y02T10/22C01P2006/12B01J23/8986B01J37/033C01P2002/34C01G55/002C01P2004/80B01J23/894B01J37/0244B01J37/0248B01J35/002B01J21/066C01P2006/80B01J2523/00Y02T10/12B01J35/30B01J2523/3706B01J2523/3712B01J2523/3725B01J2523/72B01J2523/822B01J2523/842B01J2523/31B01J2523/3718B01J2523/36
Inventor 田中裕久丹功上西真里梶田伸彦谷口昌司
Owner DAIHATSU MOTOR CO LTD