阅读说明：本技术 一种氧化钪稳定的氧化锆纳米粉体的制备方法 (Preparation method of scandia-stabilized zirconia nano-powder ) 是由 罗能能 石超 韦悦周 陈锡勇 于 2020-04-14 设计创作，主要内容包括：本发明涉及一种完全稳定的立方相氧化钪稳定的氧化锆纳米粉体的制备方法,包括前驱体母盐氧氯化锆,以及稳定剂氧化钪,其中氧化钪掺杂量占8～10mol％。制备方法包括低温水解反应和高温水热反应,首先将前驱体母盐溶液ZrOCl<Sub>2</Sub>(ScCl<Sub>3</Sub>,尿素)的水/醇类混合溶液在反应釜中进行低温水解处理,然后将水解液在160～200℃的温度下进行水热处理。产品具有粒径小、粒度分布集中、烧结温度低以及比表面积适中等特点,可适用于SOFC现行的流延成型工艺,且生产工艺简单,易于实现工业化大规模生产。(The invention relates to a preparation method of fully stable cubic phase scandia-stabilized zirconia nano-powder, which comprises a precursor mother salt zirconium oxychloride and a stabilizer scandia, wherein the doping amount of the scandia accounts for 8-10 mol%. The preparation method comprises low-temperature hydrolysis reaction and high-temperature hydrothermal reaction, and firstly, the precursor mother salt solution ZrOCl 2 (ScCl 3 Urea) is subjected to low-temperature hydrolysis treatment in a reaction kettle, and then the hydrolysate is subjected to hydrothermal treatment at the temperature of 160-200 ℃. The product has the characteristics of small particle size, concentrated particle size distribution, low sintering temperature, moderate specific surface area and the like, can be suitable for the conventional tape casting process of SOFC, has simple production process, and is easy to realize industrialized large-scale production.)

1. A preparation method of scandia-stabilized zirconia nano-powder is characterized by comprising the following steps:

(1) adding hydrochloric acid into the scandium oxide powder, and heating until the scandium oxide is dissolved to obtain a scandium oxide solution;

(2) mixing a zirconium oxychloride solution and a scandium oxide solution, and performing ultrasonic stirring to uniformly mix the zirconium oxychloride solution and the scandium oxide solution to obtain a precursor clear solution;

(3) adding urea serving as a mineralizer into the clear precursor solution obtained in the step (2), simultaneously adding CTAB or a mixture of CTAB and PEG400 serving as a dispersing agent, and ultrasonically dissolving the mixture in a mixed solution of deionized water and absolute ethyl alcohol to obtain a hydrothermal clear precursor solution;

(4) hydrolyzing the clear solution of the hydrothermal precursor obtained in the step (3) at 80 ℃ for 12-24 hours;

(5) after the low-temperature hydrolysis in the step (4) is finished, immediately adjusting the temperature to 160-200 ℃, carrying out high-temperature hydrothermal for 36-64 hours, and standing until natural cooling to obtain a white turbid solution;

(6) and centrifuging the white turbid solution, cleaning for multiple times to obtain a white precipitate, drying and grinding to obtain the scandia-stabilized zirconia nano powder.

2. The method for producing a scandia-stabilized zirconia nanopowder according to claim 1, wherein the scandia content in the scandia-stabilized zirconia nanopowder is 8 to 10 mol%.

3. The method for preparing scandia-stabilized zirconia nanopowder according to claim 1, wherein the molar ratio of scandia to HCl in the step (1) is greater than 1:6, the concentration of hydrochloric acid is 1-10 mol/L, and the temperature for heating and dissolving is greater than 100 ℃.

4. The method for preparing the scandia-stabilized zirconia nanopowder according to claim 1, wherein the zirconium oxychloride solution and the scandia solution in the step (2) are mixed according to the doping amount of scandia being 8-10 mol%, and the solute concentration in the precursor clarified solution prepared in the step (2) is 0.2-0.6 mol/L.

5. The method for preparing scandia-stabilized zirconia nanopowder according to claim 1, wherein in the mixed solution of deionized water and absolute ethyl alcohol in the step (3), the volume ratio of the deionized water to the absolute ethyl alcohol is 1: 0.5-1: 2.

6. The method for preparing the scandia-stabilized zirconia nanopowder according to claim 1, wherein the molar concentration ratio of the urea in the step (3) to the solute in the precursor clarified solution is 1: 1-4: 1.

7. The method for preparing the scandia-stabilized zirconia nanopowder according to claim 1, wherein the addition amount of the dispersant in the step (3) accounts for 1-5 wt% of the total mass of the solute in the precursor clear solution.

8. The method for preparing scandia-stabilized zirconia nanopowder according to claim 1, wherein the solution used for cleaning in step (6) is deionized water and absolute ethyl alcohol.

9. The method for preparing the scandia-stabilized zirconia nanopowder according to claim 1, wherein the secondary aggregation particle size of the scandia-stabilized zirconia nanopowder is 0.2-1 um.

Technical Field

The invention relates to a preparation method of cubic phase scandium oxide stabilized zirconia nano powder.

Background

Solid Oxide Fuel Cells (SOFC) are a novel electrochemical power generation device. Because of its advantages of environmental friendliness and high energy conversion rate, it is receiving more and more attention.

At present, the cityThe electrolyte used in most commercially available SOFCs is Yttria Stabilized Zirconia (YSZ) at 6-10 mol. However, the conventional SOFC device using YSZ as electrolyte has disadvantages such as high operation temperature (800-1000 ℃), difficult packaging, poor interface stability, poor conductivity, etc. In the related experimental reports, the scandia-stabilized zirconia system has higher ionic conductivity and low working temperature (600-800 ℃) in the stabilized zirconia system. Wherein the ingredient is (Sc)₂O₃)_0.08(ZrO₂)_0.92(8ScZr) has the highest conductivity among the zirconium-based oxygen ion conductors.

The cubic-phase scandia-stabilized zirconia is an excellent oxygen ion conductor, has excellent oxygen ion conductivity under the condition of medium temperature (600-800 ℃), has excellent stability at the temperature, and is the most promising SOFC electrolyte at present. Therefore, the synthesis of zirconia with stable cubic phase is of great significance.

There are many methods for preparing scandia-stabilized zirconia at present, and a coprecipitation method, a sol-gel method, a solid phase method, a thermal decomposition method, a spray thermal decomposition method, and a hydrothermal method have been reported. Lee et al prepared 8 mol% scandium stabilized zirconia powder by glycine-nitrate method, sintered at 1600 ℃ for 6 hours to form pure cubic phase or tetragonal sintered body with conductivity of 0.15S/cm (800 ℃). Anshenli and the like synthesized scandia-stabilized zirconia (9 mol% Sc) by a coprecipitation method₂O₃) And (3) powder. Mizutani Yasunobu and the like take scandium powder, zirconium salt and nitric acid as raw materials, and prepare scandia-stabilized zirconia powder by respectively adopting a coprecipitation method and a sol-gel method, wherein the powder can be finally prepared into an electrode plate product only through isostatic pressing and under the harsh condition of sintering at the high temperature of 1500-1700 ℃. Y.Mizutani et al ZrO (NO)₃)₂And Sc with a purity of 99.9%₂O₃8ScSZ powder is prepared by a sol-gel method, and the powder is hot pressed and sintered at the temperature of 1600-1700 ℃ (the pressure is 2000Kg/cm2) for 5-15 hours, and then the conductivity is measured to be 0.38S/cm (1000 ℃).

In summary, the existing preparation techniques such as sol-gel and coprecipitation are difficult to implement industrial mass production, and the methods such as coprecipitation can rapidly increase local concentration due to the addition of a precipitant (mineralizer), which results in hard agglomeration and uneven doping of the prepared powder. Moreover, the powder prepared by the method has the defects of over-high sintering temperature and harsh forming conditions, and is not easy to use in industrial large-scale production.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide the preparation method of the scandia-stabilized zirconia nano-powder used in the solid fuel cell, the prepared product has the characteristics of small particle size, concentrated particle size distribution and moderate specific surface area, can be suitable for the existing tape-casting process of the SOFC, and has the advantages of simple and safe production process, low equipment requirement, high yield, low raw material cost and easy realization of industrial production.

The technical scheme adopted for realizing the purpose is as follows:

a preparation method of scandia-stabilized zirconia nano-powder comprises the following steps:

(1) adding hydrochloric acid into the scandium oxide powder, and heating until the scandium oxide is dissolved to obtain a scandium oxide solution;

(2) mixing a zirconium oxychloride solution and a scandium oxide solution, and performing ultrasonic stirring to uniformly mix the zirconium oxychloride solution and the scandium oxide solution to obtain a precursor clear solution;

(3) adding urea serving as a mineralizer into the clear precursor solution obtained in the step (2), simultaneously adding CTAB or a mixture of CTAB and PEG400 serving as a dispersing agent, and ultrasonically dissolving the mixture in a mixed solution of deionized water and absolute ethyl alcohol to obtain a hydrothermal clear precursor solution;

(4) hydrolyzing the clear solution of the hydrothermal precursor obtained in the step (3) at 80 ℃ for 12-24 hours;

(5) after the low-temperature hydrolysis in the step (4) is finished, immediately adjusting the temperature to 160-200 ℃, carrying out high-temperature hydrothermal for 36-64 hours, and standing until natural cooling to obtain a white turbid solution;

(6) and centrifuging the white turbid solution, cleaning for multiple times to obtain a white precipitate, drying and grinding to obtain the scandia-stabilized zirconia nano powder.

Preferably, in the scandia-stabilized zirconia nanopowder, the content of scandia is 8-10 mol%.

Preferably, the molar ratio of scandium oxide to HCl in the step (1) is more than 1:6, the concentration of hydrochloric acid is 1-10 mol/L, and the temperature for heating and dissolving is more than 100 ℃.

Preferably, the zirconium oxychloride solution and the scandium oxide solution in the step (2) are mixed according to the doping amount of scandium oxide of 8-10 mol%, and the solute concentration in the precursor clear solution prepared in the step (2) is 0.2-0.6 mol/L.

Preferably, in the mixed solution of the deionized water and the absolute ethyl alcohol in the step (3), the volume ratio of the deionized water to the absolute ethyl alcohol is 1: 0.5-1: 2.

Preferably, the molar concentration ratio of the urea in the step (3) to the solute in the precursor clear solution is 1: 1-4: 1.

Preferably, the addition amount of the dispersing agent in the step (3) accounts for 1-5 wt% of the total mass of the solute in the precursor clear solution.

Preferably, the solution used for washing in the step (6) is deionized water and absolute ethyl alcohol.

The size of the twice-agglomerated particle diameter of the scandia-stabilized zirconia nano-powder prepared by the preparation method is 0.2-1 um.

Compared with the prior art, the invention has the following advantages.

(1) The invention adopts urea as a mineralizer, combines a uniform coprecipitation method and a hydrothermal method, and uniformly releases ammonia water during the heating process by urea hydrolysis, thereby avoiding the uneven precipitation caused by adding other mineralizers (ammonia water/sodium hydroxide solution and the like) from the outside in the traditional process, ensuring that the particle size of the product powder is more uniform and large-scale agglomeration is not easily formed.

(2) The invention is in a clear solution state before low-temperature hydrolysis and high-temperature hydrothermal, is easy to transfer into a reaction kettle container, does not cause accelerated damage to equipment or reduction of yield due to raw material residue, and saves certain cost.

(3) The invention needs simple equipment and does not need to additionally customize a special hydrothermal reaction kettle which can additionally feed materials in the hydrothermal process.

(4) The powder has the characteristics of small particle size and concentrated particle size distribution, can be suitable for the existing tape-casting process of SOFC, has simple and safe production process, lower cost and low requirement on equipment, and is easy to realize industrialized mass production.

Drawings

FIG. 1: the process flow diagram of the invention;

FIG. 2: XRD patterns of scandia-stabilized zirconia nanopowders of examples 1 to 4.

Detailed Description

For better illustrating the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to specific embodiments below: