Composite zirconium-cerium oxide, process for the preparation thereof, and cocatalyst for cleaning exhaust gas

A technology for composite oxides and manufacturing methods, applied in the direction of metal/metal oxide/metal hydroxide catalysts, physical/chemical process catalysts, rare earth metal oxides/hydroxides, etc., can solve the problem of specific surface area reduction, mixing , Inappropriate and other problems, to achieve good reproducible results

Inactive Publication Date: 2000-01-19
SOLVAY SPECIAL CHEM JAPAN LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the crystal particle diameter in the oxide state is very small, so it is very sensitive to thermal energy. When the oxides prepared by these known methods are sintered in a high temperature region above 900 ° C, the specific surface area is significantly reduced, and

Method used

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  • Composite zirconium-cerium oxide, process for the preparation thereof, and cocatalyst for cleaning exhaust gas
  • Composite zirconium-cerium oxide, process for the preparation thereof, and cocatalyst for cleaning exhaust gas
  • Composite zirconium-cerium oxide, process for the preparation thereof, and cocatalyst for cleaning exhaust gas

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] 81.05 g of zirconium hydroxide powder (manufactured by Santoku Metal Industry Co., Ltd., purity 99.9%, converted to zirconium hydroxide content of 40.1% by weight, average particle diameter of 18.56 μm), 150 ml of cerium sol (ロ-ヌ·プ- 16.67ml of lanthanum nitrate aqueous solution (manufactured by Anan Kasei Co., Ltd., purity 99.9%, 150g / liter converted to lanthanum oxide concentration). l) mixed to obtain ZrO 2 : CeO 2 : La 2 o 3 = 65:30:5 (weight ratio) mixture. Nitric acid (manufactured by Wako Pure Chemical Industries, Ltd., purity 60-61%) was added to the mixture so that its presence reached 6 times the total molar amount of cerium, and then the concentration in terms of oxides was adjusted to 50 g / liter with desalted water, 1 liter of mixture was obtained. Then 1 liter of this mixture was transferred to a vessel equipped with a steam cooling tube and heated at 100°C for 12 hours with stirring. After cooling slowly to 20°C, ammonia water (manufactured by Wako Pu...

Embodiment 2

[0046] 93.52g of zirconium hydroxide powder used in Example 1, 100ml of cerium sol and 16.67ml of lanthanum nitrate aqueous solution were mixed to obtain ZrO 2 : CeO 2 : La 2 o 3 =75:20:5 (weight ratio) mixture. Nitric acid was added to the mixture so that the amount was 6.2 times the molar amount of cerium, and the concentration in terms of oxide was adjusted to 50 g / liter with desalted water to obtain 1 liter of the mixture. Next, stirring and heating were carried out in the same manner as in Example 1, ammonia water was added, and the product was subjected to solid-liquid separation to obtain 142 g of precipitates. The obtained precipitate was subjected to X-ray diffraction measurement under the same conditions as in Example 1. The exact crystallite diameter could not be measured, and the X-ray intensity showing crystallinity was about 700 cps. Carry out firing similarly with embodiment 1, obtain specific surface area 115.7m 2 / g of zirconium-cerium-based lanthanum-co...

Embodiment 3

[0048] The zirconium hydroxide powder used in 93.52g embodiment 1 is mixed with 125ml cerium sol, obtains ZrO 2 : CeO 2 =75:25 (weight ratio) mixture. Nitric acid was added to the mixture in an amount of 5.5 times moles of the total molar amount of cerium, and the concentration was adjusted to 50 g / liter in terms of oxides with desalted water to obtain 1 liter of the mixture. Next, it operated similarly to Example 1, and obtained 141.62 g of precipitates. The obtained precipitate was subjected to X-ray diffraction measurement under the same conditions as in Example 1. The exact crystallite diameter could not be measured, and the X-ray intensity showing crystallinity was about 700 cps. Then operate in the same way as in Example 1 to obtain a specific surface area of ​​112.4m 2 / g of zirconium-cerium-based lanthanum-containing composite oxide 50g. Table 1 shows the specific surface areas when the obtained composite oxides were heated at 900°C, 1000°C, and 1100°C for 6 hours...

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Abstract

A zirconium-cerium composite oxide having excellent heat resistance and being capable of maintaining its large specific surface area even when used under high-temperature conditions, which composite oxide contains zirconium and cerium at a weight ratio of 51 to 95:49 to 5 in terms of zircomium oxide and ceric oxide, the composite oxide having a specific surface area of not smaller than 50 m2/g, wherein said composite oxide is capable of maintaining a specific surface area of not smaller than 20 m2/g even after heating at 1100 DEG C. for 6 hours, a method for preparing the same, and a co-catalyst for purifying exhaust gas prepared with the composite oxide.

Description

field of invention [0001] The present invention relates to a zirconium-cerium composite oxide with good heat resistance, which can be used in the field of catalysts, the field of functional ceramics, the field of solid electrolytes for fuel cells, etc. A production method and a co-catalyst for exhaust gas purification. Background of the invention [0002] Catalysts for purifying exhaust gas of automobiles are generally composed of catalyst supports such as alumina and cordierite, which carry catalyst metals such as platinum, palladium, rhodium, etc., and co-catalysts for enhancing their catalytic effects. The cerium oxide-based material used as the cocatalyst has the characteristics of absorbing oxygen in an oxidizing atmosphere and releasing oxygen in a reducing atmosphere. Using this oxygen absorption and release energy can effectively purify hydrocarbons, carbon monoxide and nitrogen oxides in exhaust gas and other harmful components, therefore, cerium oxide-based materi...

Claims

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Application Information

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IPC IPC(8): B01D53/86B01D53/94B01J23/10B01J35/10C01G25/00
CPCB01J23/10B01J35/10B01D53/94B01D53/86C01G25/00B01J35/002B01J35/023B01J35/1014B01J35/1019B01J21/066C01G25/02C01P2004/61C01F17/206
Inventor 青笹繁
Owner SOLVAY SPECIAL CHEM JAPAN LTD
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