Palladium-doped lanthanum ferrite powder preparation method

A technology of lanthanum ferrite and powder is applied in the field of preparation of palladium-doped lanthanum ferrite powder, which can solve the problems of high price, toxicity, and no application prospect.

Inactive Publication Date: 2014-07-16
LANZHOU UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the metal alkoxide used in the preparation of palladium-doped lanthanum ferrite powder by the alkoxide hydrolysis method is an organic salt, and the price is relatively high. The organic reagent used is toluene, which is toxic and belongs to the drug controlled by the Ministry of Public Security.
Therefore, this preparation technology is only suitable for a small amount of laboratory synthesis of palladium-doped lanthanum ferrite powder for scientific research work, and has no application prospects

Method used

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Examples

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Embodiment 1

[0024] Raw materials: lanthanum nitrate, iron nitrate, palladium nitrate, citric acid, all of analytical grade.

[0025] proportionally Proportioning, where x=0.05, weigh lanthanum nitrate, ferric nitrate and palladium nitrate. Dissolve lanthanum nitrate, iron nitrate and palladium nitrate in deionized water respectively, mix the three solutions, and add citric acid therein, the amount of citric acid is 1.3 times of the total molar weight of lanthanum nitrate, iron nitrate and palladium nitrate. Boiling water is refluxed to mix the solution evenly to obtain a transparent sol. After the sol evaporates part of the water in a 70°C water bath, a wet gel with a high viscosity is obtained. The wet gel is placed in a vacuum drying oven and depressurized at 60°C for 4 hours. Dried to obtain the precursor xerogel powder, and then calcined the precursor xerogel powder at 800° C. for 1 hour to obtain palladium-doped lanthanum ferrite powder.

[0026] figure 1 It is the X-ray diffract...

Embodiment 2

[0028] Raw materials: Lanthanum nitrate, ferric nitrate, palladium nitrate, citric acid and polyethylene glycol 2000 are all analytically pure.

[0029] proportionally Proportioning, where x=0.1, weigh lanthanum nitrate, ferric nitrate and palladium nitrate. Dissolve lanthanum nitrate, iron nitrate and palladium nitrate with deionized water respectively, after mixing the three solutions, add citric acid and polyethylene glycol 2000 to it, the amount of citric acid is the total molar weight of lanthanum nitrate, iron nitrate and palladium nitrate The amount of polyethylene glycol 2000 is 0.05 times of the weight of citric acid, and the solution is mixed evenly by ultrasonic oscillation to obtain a transparent sol. The sol is evaporated in a 60°C water bath to obtain a wet gel with high viscosity. , the wet gel was placed in a vacuum drying oven and dried under reduced pressure at 70°C for 3 hours to obtain a precursor xerogel powder, which was then calcined at 700°C for 2 hou...

Embodiment 3

[0032] Raw materials: Lanthanum nitrate, ferric nitrate, palladium nitrate, citric acid and polyethylene glycol 20000 are all analytically pure.

[0033] proportionally Proportioning, where x=0.08, weigh lanthanum nitrate, ferric nitrate and palladium nitrate. Dissolve lanthanum nitrate, ferric nitrate and palladium nitrate with deionized water respectively, after mixing the three solutions, add citric acid and polyethylene glycol 20000 to it, the amount of citric acid is the total molar weight of lanthanum nitrate, ferric nitrate and palladium nitrate The amount of polyethylene glycol 20000 is 0.3 times of the weight of citric acid, and heated to reflux at 80°C to mix the solution evenly to obtain a transparent sol. The sol has a higher viscosity after evaporating part of the water in a water bath at 80°C. Wet gel, the wet gel is placed in a vacuum drying oven and dried under reduced pressure at 50°C for 6 hours to obtain the precursor dry gel powder, which is then roasted ...

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Abstract

The present invention discloses a palladium-doped lanthanum ferrite powder preparation method, which comprises: selecting raw materials such as lanthanum nitrate, iron nitrate, palladium nitrate, citric acid and polyethylene glycol; and respectively weighing lanthanum nitrate, iron nitrate and palladium nitrate according to a ratio of mol(La)<3+> to mol(Fe)<3+> to mol(Pd)<2+> of 1:(1-x):x, adopting deionized water to respectively dissolve, mixing the obtained three solutions, adding citric acid and polyethylene glycol, uniformly mixing to obtain a transparent sol, evaporating water from the sol to obtain a wet gel, drying the wet gel to obtain precursor dry gel powder, and calcining the precursor dry gel powder to obtain the palladium-doped lanthanum ferrite powder, wherein x is 0.05-0.1, the molar amount of the added citric acid is 1.0-1.5 times the total molar amount of the lanthanum nitrate, the iron nitrate and the palladium nitrate, and the weight of the added polyethylene glycol is 0-0.3 time the weight of the citric acid. The method has advantages of low cost, market prospects, high product sample purity, good uniformity and the like.

Description

technical field [0001] The invention relates to a method for preparing a catalyst used in automobile exhaust purification, in particular to a method for preparing palladium-doped lanthanum ferrite powder. Background technique [0002] Lanthanum ferrite (LaFeO3) belongs to the perovskite (ABO3) type oxide, which has two kinds of structures, orthogonal and cubic. With the different doping elements and amounts of A-site and B-site, the system materials have magnetic, electrical conductivity, piezoelectricity, photoelectric properties, etc., and can be applied to solid electrolytes, solid fuel cells, electrochemical devices, sensors and photoelectric properties. catalysis and other fields. By consulting the literature and related research, we found that palladium-doped lanthanum ferrite can be used as a smart catalyst for automobile exhaust. [0003] The preparation methods of lanthanum ferrite powder mainly include solid-state reaction method, co-precipitation method, sol-gel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G49/00B01J23/89
Inventor 段迎文
Owner LANZHOU UNIVERSITY
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