Cerium-based carbon-containing nanotube composite RE oxide and its prepn

A composite oxide and rare earth compounding technology, which is applied in chemical instruments and methods, catalyst activation/preparation, separation methods, etc., can solve problems such as poor thermal stability, reduced oxygen storage capacity, and easy sintering, and achieve good thermal stability, Good anti-sintering performance and simple preparation method

Inactive Publication Date: 2003-07-30
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Shyu J Z et al. found (see Shyu J Z, Weber W H. Surface characterizatioof alumina-supported ceria. J Phys Chem, 1988, 92 (17): 4964-4970 for details) when cerium oxide is used in TWC, above 850 ℃, thermal Poor stability, easy to sinter, easy to mix with Al in the carrier 2 o 3 A reaction occurs that reduces its oxygen storage capacity (OSC)

Method used

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  • Cerium-based carbon-containing nanotube composite RE oxide and its prepn
  • Cerium-based carbon-containing nanotube composite RE oxide and its prepn
  • Cerium-based carbon-containing nanotube composite RE oxide and its prepn

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Experimental program
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Effect test

Embodiment 1

[0024] In order to prepare 100g of composite oxides, the weights of ceria, zirconia, lanthanum oxide, praseodymium oxide and carbon nanotubes are respectively 59.5g, 30g, 4g, 6g and 0.5g. At first getting concentration is 0.3M cerium nitrate 1153ml, 0.5M zirconium nitrate 488ml, 0.5M lanthanum nitrate 49.1ml and 0.5M praseodymium nitrate 70.5ml solution, is prepared into mixed solution; Take ammonium carbonate solution as precipitation agent (the molar weight of precipitation agent is 1.1 times of precipitating agent needed for all precipitation cations), under the condition of stirring, add the carbon nanotube of 0.5g in 2M, 602ml ammonium carbonate solution, and add 17.6ml (accounting for the volume 1vol% of mixed nitric acid solution) weight hundred Divide the sodium dodecylsulfonate aqueous solution with a concentration of 5%, and stir for 30 minutes; then add the above-mentioned mixed nitric acid solution to the ammonium carbonate solution, the pH value is controlled at 8....

Embodiment 2

[0027]In order to prepare 100g of composite oxide, the weights of ceria, zirconia, lanthanum oxide, praseodymium oxide and carbon nanotubes are 50g, 39.95g, 4g, 6g and 0.05g respectively. First get concentration and be that 0.5M cerium nitrate 581.4ml, 0.3M zirconium nitrate 1083ml, 0.5M lanthanum nitrate 49.1ml and 0.5M praseodymium nitrate 70.5ml solution are prepared into mixed nitric acid solution; The amount is 1.1 times of the precipitating agent required for all precipitation cations), under the condition of stirring, add the carbon nanotube of 0.05g in the 0.5M, 2586ml ammonium oxalate solution, and add 89.2ml (accounting for the volume 5vol% of mixed nitric acid solution) The Tween 60 aqueous solution with a concentration of 1% by weight was stirred for 30 minutes, then the mixed nitric acid solution was added to the above-mentioned ammonium oxalate solution, the pH value was controlled at 7.5, and the reaction time was 80 minutes to generate a precipitate; filter the ...

Embodiment 3

[0030] Prepare 100 g of composite oxides, in which the weights of cerium oxide, zirconia, lanthanum oxide, praseodymium oxide, and carbon nanotubes are 69.7 g, 20 g, 4 g, 6 g, and 0.3 g, respectively. First, take 1351ml of 0.3M cerium nitrate, 325ml of 0.5M zirconium nitrate, 49.1ml of 0.5M lanthanum nitrate and 70.5ml of 0.5M praseodymium nitrate to make mixed solutions; (the molar weight of precipitating agent is 1.1 times of precipitating agent required for all precipitating cations) in, add the carbon nanotube of 0.3g, and add 18ml (accounting for the volume 1% of mixed nitric acid solution) concentration by weight is 5% sixteen Alkyl ammonium chloride alcohol solution, stirred for 30 minutes; then the mixed nitric acid solution was added to the above ammonium carbonate solution, the pH value was controlled at 10, the reaction time was 60 minutes, and a precipitate was formed; the precipitate was filtered, and then at 600 ° C Calcined for 1 hour. Calcined at 650°C for 4 h...

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Abstract

Oxides CeO2, ZrO2, La2O3 and Pr6O11 or their salts are prepared into mixed ionic nitric acid solution; small amount of surfactant and carbon nanotube are added into precipitant solution to prepare mixed precipitant solution; two kinds of solution are made to react to produce precipitate; and the precipitate is incinerated at 400-700 deg.c to obtain quarternary nanometer-level cerium-based carbon nanotube-containing composite RE oxide. The composite oxide has high specific surface area at both low temperature and high temperature and high heat stability. It may be used in various catalytic reaction process, such as hydrosulfurization, hydrodenitrification, dehydrohalogenation, internal combustion engine waste gas treatment and dehydrocyclization of hydrocarbon and other organic matters, and is especially suitable for use in purifying automobile tail gas.

Description

technical field [0001] The invention relates to a rare earth composite oxide and a preparation method thereof, in particular to a quaternary nanoscale rare earth composite oxide containing carbon nanotubes based on cerium and a preparation method thereof; it can be applied to the catalytic process of various reactions, Such as hydrosulfurization, hydrodenitrogenation, dehydrohalogenation, exhaust gas treatment of internal combustion engines, dehydrocyclization of hydrocarbons or other organic substances, especially suitable for purification of automobile exhaust. Background technique [0002] Cerium oxide is used as a co-catalyst in the three-way catalyst (TWC) for automobile exhaust purification, mainly because cerium Ce 3+ and Ce 4+ There is a reversible transformation between them, and it has a good oxygen storage capacity (OSC). Cerium oxide easily releases oxygen under reducing conditions, making CO and CH x Oxidation; storage of oxygen under oxidative conditions so ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/94B01J23/10B01J37/03
Inventor 刘明芬王秋萍宋崇立陈靖王兴海
Owner TSINGHUA UNIV
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