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Method for preparing palladium catalyst carried by composite oxides of Ce-Zr

A composite oxide and palladium catalyst technology, which is applied in the direction of catalyst activation/preparation, metal/metal oxide/metal hydroxide catalyst, physical/chemical process catalyst, etc., can solve the problem of cumbersome procedures, small specific surface area of ​​products, and long operating time long wait question

Inactive Publication Date: 2008-03-12
RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

As the production method of cerium-zirconium composite oxide published in the past, such as CN1241988A, CN1449863A, CN1387943A, etc., there are problems of long operation time, cumbersome process or small specific surface area of ​​the product

Method used

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  • Method for preparing palladium catalyst carried by composite oxides of Ce-Zr
  • Method for preparing palladium catalyst carried by composite oxides of Ce-Zr

Examples

Experimental program
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Effect test

Embodiment 1

[0010] Embodiment 1: raw material is Ce (NO 3 ) 3 ·6H 2 O and Zr(NO 3 ) 4 ·5H 2 O, citric acid is a complexing agent, prepare mixed solution 100ml, the concentration of the soluble salt solution prepared is 0.5mol / L, the concentration of citric acid is 0.2mol / L, and the mol ratio of cerium to zirconium is 1; Filter paper soaks above-mentioned mixed solution, Take out the filter paper and dry it at 80°C, then bake it in the air at 500°C for 3 hours to prepare the cerium-zirconium composite oxide; uniformly disperse the prepared cerium-zirconium composite oxide into 60ml 0.02M PdCl 2 In solution; 1mol / L Na 2 CO 3 As a precipitant, add the precipitant dropwise until the pH of the solution is 10; after standing for 2 hours, suction filter, and repeatedly rinse with deionized water; dry the obtained product at 80°C, roast at 500°C in the air for 3 hours, and then 300°C under hydrogen atmosphere Reduction at -500°C for 3 hours to prepare catalyst 1.0% Pd / Ce 0.5 Zr 0.5 o 2 ...

Embodiment 2

[0013] Embodiment 2: raw material is Ce (NO 3 ) 3 ·6H 2 O and Zr(NO 3 ) 4 ·5H 2 0, citric acid is a complexing agent, prepare mixed solution 100ml, the soluble salt solution concentration that is mixed with is 0.5mol / L, and the citric acid concentration is 0.2mol / L, and the mol ratio of cerium to zirconium is 9; All the other are with embodiment 1, Catalyst 1.0%Pd / Ce prepared 0.9 Zr 0.1 o 2 . Its ignition characteristics are shown in Table 1.

Embodiment 3

[0014] Example 3: The preparation method of the cerium-zirconium composite oxide is the same as in Example 1; the prepared cerium-zirconium composite oxide is uniformly dispersed in 40ml of 0.02M PdCl 2 In solution; All the other are with embodiment 1, make catalyst 1.5%Pd / Ce 0.5 Zr 0.5 o 2 . Its ignition characteristics are shown in Figure 3.

[0015] Table 1 Catalyst surface characteristics and light-off activity

[0016]

[0017] T 50％ with T 90％ Indicate the temperature at which 50% and 90% of the pollutants are converted, respectively

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Abstract

A process for preparing the Pd catalyst carried by complex CeZr oxide includes mixing Ce, Zr and citric acid to obtain mixed solution, immersing the fibrous substance (filter paper, print paper, paper pulp, etc) in it, baking, calcining in O2 to obtain said complex oxide, preparing Pd solution, dispersing said complex oxide in it, adding alkali to make pH=9-12, ageing, filtering, washing with deionized water, baking, calcining and reducing in H2.

Description

technical field [0001] The invention relates to a preparation method of a cerium-zirconium composite oxide supported palladium catalyst. Background technique [0002] Three-way catalyst purification is currently the most effective means of controlling automobile exhaust pollution. There are many relevant patent documents, such as JP 57184440 (1982), US 4450684 (1984), EP 734757 (1996), WO 0147634 (2001), US 6625976 (2003) etc. Foreign three-way catalysts usually adopt palladium (Pd), platinum (Pt) and rhodium (Rh) as active components, and the catalyst cost is higher; Price and efficient oxidation activity are of concern. Rare earth is often added to the three-way catalyst to improve its thermal stability and catalytic activity. Cerium oxide-based materials are the most widely used ones because of their characteristics of absorbing oxygen in an oxidizing atmosphere and releasing oxygen in a reducing atmosphere. Cerium oxide doped with zirconia has higher thermal stability,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/40B01J23/89B01J37/02B01J32/00B01D53/94
Inventor 朱保伟陈宏德田群沈迪斯
Owner RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI