Nano cerium-zirconium composite oxide and application thereof in catalysis of NOX reduction reaction

A technology of composite oxides and zirconium oxides, applied in the direction of metal/metal oxide/metal hydroxide catalysts, zirconium compounds, catalyst activation/preparation, etc., can solve the problems of catalyst pollutant conversion efficiency, low surface activity, Few active sites, etc., to achieve excellent low-temperature catalytic activity, excellent high-temperature stability, and excellent catalytic advantages

Active Publication Date: 2019-12-03
SHANDONG SINOCERA FUNCTIONAL MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

If the size is too small, the surface activity is too high, and it is easy to agglomerate, which will lead to a sharp drop in the specific surface area after high temperature aging; if the size is too large, the initial specific surface area is too low, and there are fewer active sites. At the same time, the surface activity energy is low. The above two factors will affect the conversion efficiency of the catalyst to pollutants

Method used

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  • Nano cerium-zirconium composite oxide and application thereof in catalysis of NOX reduction reaction
  • Nano cerium-zirconium composite oxide and application thereof in catalysis of NOX reduction reaction
  • Nano cerium-zirconium composite oxide and application thereof in catalysis of NOX reduction reaction

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preparation example Construction

[0051] The embodiment of the present invention provides a preparation method of nano-cerium-zirconium composite oxide, the specific steps include:

[0052] S1, dissolve the salts of cerium, zirconium, lanthanum and praseodymium or yttrium respectively, set the volume to a total concentration of 40-140g / L, stir until clear, and continue to stir at a low speed for 0.5h;

[0053] S2, drop an alkaline precipitant into the above solution, the alkaline precipitant is one or more of ammonia, sodium hydroxide, amines, preferably ammonia, and then adjust the pH of the solution to 1.5- 2;

[0054] S3, introducing the above solution into a high-pressure reactor, and hydrolyzing it at 150° C. for 10-20 hours;

[0055] S4, adding an alkaline precipitant dropwise to the precursor slurry obtained in S3 to adjust the pH to 8-10;

[0056] S5, introducing the precursor slurry obtained in S4 into an autoclave, and performing a hydrothermal reaction at 150° C. for 6-10 hours;

[0057] S6, beat...

Embodiment 1

[0060] Embodiment 1 provides a composition based on cerium oxide, zirconia, lanthanum oxide, and yttrium oxide, and the composition is CeO in proportion by weight of the oxide 2 28%, ZrO 2 62%, La 2 o 3 5%, Y 2 o 3 5%.

[0061] The equipment used in this embodiment is a 10L polytetrafluoro-lined high-pressure reactor, the solution filling degree is 80%, and the total concentration of oxides is 40g / l. Its preparation method is as follows:

[0062] Get 574g of zirconium oxynitrate, 54.2g of yttrium nitrate, dissolve with 2000ml of deionized water until clear to obtain solution A;

[0063] Take 278.5g of ammonium cerium nitrate and 42.7g of lanthanum nitrate into solution A, stir until clear, adjust the pH of solution A to 1.5-1.6 with ammonia water in a water bath at 50°C, set the volume to 8000ml, and introduce In the vinyl fluoride-lined pressure melting bomb, hydrothermal hydrolysis reaction at 150°C for 20 hours, lowered to room temperature and adjusted pH to 9.5-9...

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Abstract

The invention provides a nano cerium-zirconium composite oxide. The nano cerium-zirconium composite oxide comprises ceria, zirconia and at least one of rare-earth metal oxides except for cerium oxides, wherein a mass percent ratio of a cerium oxide to a zirconium oxide in the composite oxide is smaller than 1; and after heat treatment of 4 to 8 hours at the temperature of 750 DEG C, the compositeoxide has the particle size of 5nm to 20nm and the oxygen storage capacity of at least 1.10mmol[O] / g. The nano cerium-zirconium composite oxide provided by the invention has a proper microscopic nanoparticle size and relatively high oxygen storage capacity. Shown by experiments, after 4 hours of calcination of the nano cerium-zirconium composite oxide provided by the invention at the temperatureof 750 DEG C, T50 and T90 are about 150 DEG C and 200 DEG C separately, after 4 hours of high-temperature aging at the temperature of 1,100 DEG C, the T50 and the T90 are about 170 DEG C and 220 DEG Cseparately, and thus, excellent low-temperature catalytic activity and antiaging activity are shown.

Description

technical field [0001] The invention relates to the technical field of mobile source tail gas purification catalysis, in particular to a nano-cerium-zirconium composite oxide and its catalytic performance in NO X Applications in reduction reactions. Background technique [0002] Mobile source is the abbreviation of mobile air pollution source, which can produce a large amount of pollutants, for example, the cold start phase of the engine can emit a large amount of nitrogen-containing compounds, such as nitrogen monoxide (NO), nitrogen dioxide (NO 2 ) and other nitrogen oxides (NO X ) and ammonia (NH 3 )Wait. At present, the main means to solve the cold start exhaust problem is to install a purifier with a built-in catalyst at the exhaust emission of the vehicle. [0003] Cerium-zirconium composite oxides are widely used in the field of automobile exhaust catalysis. In addition to participating in the catalytic reaction, the cerium-zirconium composite oxide also has the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G25/00B82Y40/00B82Y30/00B01J23/63B01J37/10B01J37/02B01J37/03B01D53/94B01D53/56B01D53/86
CPCB01D53/8628B01D53/9413B01D2258/012B01J23/002B01J23/63B01J37/0201B01J37/031B01J37/10B01J2523/00B82Y30/00B82Y40/00C01G25/006C01P2004/04C01P2004/64C01P2004/82B01J2523/36B01J2523/3706B01J2523/3712B01J2523/48
Inventor 宋锡滨邢晶刘洪升潘光军
Owner SHANDONG SINOCERA FUNCTIONAL MATERIAL CO LTD
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