A kind of CEO2 base scr catalyst and preparation method thereof

A technology of SCR catalysts and oxides, which is applied in chemical instruments and methods, physical/chemical process catalysts, separation methods, etc., can solve the problems of anti-sulfurization, weak anti-hydrothermal aging performance, and limited use of catalysts, so as to improve the resistance Vulcanization performance, cost reduction, effect of increasing specific surface area

Inactive Publication Date: 2016-02-10
SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the above-mentioned SCR catalyst can achieve a NOx conversion rate of more than 80% within a certain temperature range during NOx purification treatment, its anti-sulfidation and hydrothermal aging resistance are not strong, which also limits the use of the catalyst.

Method used

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  • A kind of CEO2 base scr catalyst and preparation method thereof
  • A kind of CEO2 base scr catalyst and preparation method thereof
  • A kind of CEO2 base scr catalyst and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

experiment example 1

[0025] Experimental Example 1: Prepared by dipping method.

[0026] 1) Take a certain amount of CeO 2 The cerium-zirconium solid solution powder accounts for 80 wt%, and the selected amount ensures that the mass fraction of the metal oxide in the whole catalyst is 90%. The powder can only contain CeO 2 , the reason why doped ZrO 2 , because doping ZrO 2 After that, the CeO can be increased 2 Stability during catalytic reduction reactions. Similarly, the metal oxide powder can also be doped with Al 2 o 3 or SiO 2 .

[0027] 2) Take a certain amount of (NH 4 ) 2 HPO 4 and ZrOCl 2 ·8H 2 O, the selected amount guarantees PO 4 3- +Zr 4+ The mass fraction of the heteropolyacid material that forms accounts for the whole catalyst that makes afterwards is 10%, Zr 4+ with PO 4 3- Dissolve in deionized water at a molar ratio of 1:1 to form a clear aqueous solution, and Zr in the aqueous solution 4+ and PO 4 3- The sum of the ion concentrations is 1molL -1 .

[002...

experiment example 2

[0036] Experimental example 2: the same as the preparation process of experimental example 1, the difference is only: the difference in quality, so that the massfraction of the metal oxide accounted for the whole catalyst made is 80%, the massfraction of porous heteropolyacid material is 20%. Zr in heteropoly acid substances 4+ and PO 4 3- The molar ratio is still 1. The prepared catalyst was designated as A-2.

[0037] Test the selective catalytic reduction performance of the catalyst A-2, and the selective catalytic reduction performance after sulfurization treatment and hydrothermal treatment. The test method is the same as that in Experimental Example 1 and will not be repeated here. The test calculation results are shown in Table 1.

experiment example 3

[0038] Experimental Example 3: the same preparation process as Experimental Example 1, the only difference is: the difference in quality makes the metal oxide account for 70% of the mass fraction of the whole catalyst made, and the mass fraction of the porous heteropolyacid substance is 30%. Zr in heteropoly acid substances 4+ and PO 4 3- The molar ratio is still 1. The prepared catalyst was designated as A-3.

[0039] Test the selective catalytic reduction performance of the catalyst A-3, and the selective catalytic reduction performance after sulfurization treatment and hydrothermal treatment. The test method is the same as that in Experimental Example 1 and will not be repeated here. The test calculation results are shown in Table 1.

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Abstract

The invention discloses a CeO2 based SCR catalyst and a preparation method thereof. The preparation method comprises the following steps: taking a proper amount of a metal oxide powder containing CeO2 or a metal salt solution including soluble salt of Ce; soluble salts; taking a proper amount of a mixed water solution containing soluble phosphate and soluble salt of zirconium, wherein the molar ratio of Zr<4+> and PO43 in the mixed water solution is 0.5-2, and the ion total concentration of Zr<4+> and PO4<3-> is 0.1-5mol / L; forming a porous heteropoly acid substance by the Zr<4+> and PO4<3-> in the mixed aqueous solutions; adsorbing the heteropoly acid substance on the surface of metal oxide by using an impregnation method, or complexing the soluble salt solution of Ce and the heteropoly acid substance to form sol under the assistance of a complexing agent by using a sol gel method; and finally drying and roasting to prepare a catalyst powder. The mass fraction of metal oxide in the catalyst is 60%-95%, and the mass fraction of heteropoly acid substance is 5%-40%. The catalyst prepared by the invention has strong water thermal aging and sulfuration resistance ability, and low cost.

Description

【Technical field】 [0001] The present invention relates to SCR catalyst, particularly relates to a kind of CeO 2 Based SCR catalyst and preparation method thereof. 【Background technique】 [0002] Compared with gasoline vehicles, diesel vehicles have higher thermal efficiency, better economy, and CO 2 The characteristics of low emission, but due to the characteristics of diesel engine, the emission of NOx and particulate matter (liquid-phase soluble organic matter SOF and solid-phase dry soot C and solid particulate matter such as sulfate) is higher than that of gasoline vehicles, among which NOx is a kind of The main pollutants have constituted a great harm to environmental protection and human health. Since the diesel engine is a lean-burn engine, the O in the exhaust gas 2 The concentration is high (>6%), so the three-way catalyst (TWC) cannot be used to remove NOx like gasoline vehicles, and an SCR catalyst must be installed in the exhaust after-treatment device to p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/18B01J27/188B01J27/19B01J27/182B01D53/90B01D53/56
Inventor 翁端司知蠢於俊吴晓东王敏
Owner SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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