ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δElectrocatalytic material and preparation thereof
阅读说明：本技术 ABO3型高熵钙钛矿Bax(FeCoNiZrY)0.2O3-δ电催化材料及其制备 (ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δElectrocatalytic material and preparation thereof ) 是由 刘天西 楚凯斌 赖飞立 于 2021-09-26 设计创作，主要内容包括：本发明公开了ABO-(3)型高熵钙钛矿Ba-(x)(FeCoNiZrY)-(0.2)O-(3-δ)电催化材料及其制备,属于电催化材料技术领域。本发明的电催化材料以水合硝酸钴、水合硝酸铁、水合硝酸镍、硝酸钡、水合硝酸钇,水合硝酸锆和聚丙烯腈短纤为原料,经过液相螯合,凝胶化和焙烧等过程制备得到。所制备的高熵钙钛矿Ba-(x)(FeCoNiZrY)-(0.2)O-(3-δ)电催化材料因其特殊的纳米结构,从而能释放出更多的电化学活性位点,展现出更优异的电催化活性。同时,通过调节A/B位金属的化学计量比,实现了催化中心五金属的电子结构变化以及氧空位含量的变化,达到了对氮气还原性能的调节和优化的目的,具有优异的电催化转化氮气成氨气的性能。(The invention discloses ABO 3 Type high entropy perovskite Ba x (FeCoNiZrY) 0.2 O 3‑δ An electro-catalytic material and a preparation thereof, belonging to the technical field of electro-catalytic materials. The electrocatalytic material is prepared by taking cobalt nitrate hydrate, ferric nitrate hydrate, nickel nitrate hydrate, barium nitrate, yttrium nitrate hydrate, zirconium nitrate hydrate and polyacrylonitrile short fiber as raw materials and carrying out liquid phase chelation, gelation, roasting and other processes. Prepared high-entropy perovskite Ba x (FeCoNiZrY) 0.2 O 3‑δ The electrocatalytic material can release more electrochemical active sites due to the special nano structure of the electrocatalytic material, and shows more excellent electrocatalytic activity. Meanwhile, the electronic structure change of five metals in the catalytic center and the change of the oxygen vacancy content are realized by adjusting the stoichiometric ratio of A/B site metal, and the adjustment of the nitrogen reduction performance is realizedThe optimization aims at having excellent performance of converting nitrogen into ammonia by electrocatalysis.)
1. An electrocatalyst for ammonia synthesis, wherein the catalyst is ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material; wherein, ABO3The metal in the A site in the type is Ba; the B site contains metals Fe, Co, Ni, Zr and Y, x is 0.9 and 1, and delta is more than 0 and less than 3.
2. An ammonia synthesis electrocatalyst according to claim 1, wherein the atomic ratio of metals is: ba: fe: co: ni: zr: and Y is 1: 0.2: 0.2: 0.2: 0.2: 0.2 or Ba: fe: co: ni: zr: y is 0.9: 0.2: 0.2: 0.2: 0.2: 0.2.
3. a method of preparing an ammonia synthesis electrocatalyst according to claim 1 or 2, comprising the steps of:
(1) dissolving polyacrylonitrile powder in N, N-dimethylformamide to obtain polyacrylonitrile solution, then carrying out electrostatic spinning, pre-oxidizing a membrane obtained by electrostatic spinning at high temperature, and then smashing and dispersing the pre-oxidized membrane in water to form dispersion liquid;
(2) dissolving barium salt, iron salt, cobalt salt, nickel salt, zirconium salt and yttrium salt in water to form aqueous solution; then adding a certain amount of glycol and citric acid to chelate metal salt to form a clear solution, adjusting the pH to 7-9 with ammonia water, heating and concentrating to form gel, adding the preoxidized polyacrylonitrile staple fiber dispersion liquid obtained in the step (1), continuously concentrating to form gel, and removing the solvent at high temperature to prepare precursor powder;
(3) roasting the precursor powder obtained in the step (2) to obtain ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material.
4. The method as claimed in claim 3, wherein in the step (1), the concentration of the polyacrylonitrile solution is 0.08-0.12g/mL, and the condition of electrostatic spinning is 15-20 kV.
5. The method as claimed in claim 3 or 4, wherein the pre-oxidation temperature in step (1) is 150 ℃ to 200 ℃ and the time is 2-5 h.
6. The method according to any one of claims 3 to 5, wherein in step (2), the cobalt salt comprises: co (NO)3)2·6H2O, the concentration is 1.0-1.5 mg/mL; the nickel salt includes: ni (NO)3)2·6H2O, the concentration is 1.0-1.5 mg/mL; the iron salts include: fe (NO)3)3·9H2O, the concentration is 1.5-2.0 mg/mL; the zirconium salt comprises: zr (NO)3)4·5H2O, the concentration is 1.5-2.0 mg/mL; the yttrium salt comprises: y (NO)3)3·6H2O, the concentration is 1.5-2.0 mg/mL; the barium salt comprises: ba (NO)3)2The barium salt concentration is 4.0-5.0mg/mL when x is 0.9, and 5.0-5.5mg/mL when x is 1.
7. The method according to any one of claims 3 to 6, wherein the concentration of citric acid in the aqueous solution in the step (2) is 10.0 to 15.0mg/mL, and the concentration of ethylene glycol is 5.0 to 10.0 mg/mL.
8. The method as claimed in any one of claims 3 to 7, wherein in step (3), the calcination temperature is 800-1200 ℃ and the calcination time is 5-10 h.
9. A method for producing ammonia gas, characterized in that the method uses the electrocatalyst for ammonia synthesis according to claim 1 or 2 or the catalyst produced by the method according to any one of claims 3 to 8 as an electrocatalyst.
10. Use of an ammonia synthesis electrocatalyst according to claim 1 or 2 or a method according to any one of claims 3 to 8 in the field of ammonia gas production.
Technical Field
The invention belongs to the technical field of electrocatalytic materials, and particularly relates to an ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δElectrocatalytic material and its preparation.
Background
Ammonia is an important chemical and has wide applications in the industrial, agricultural and energy fields. At present, the industrial-grade ammonia synthesis method is mainly a Haber-Bosch method, and the method needs to be carried out under harsh conditions (300-500 ℃ and 150-200 atm). The energy consumption for the production of ammonia accounts for about 1% of the total global consumption every year, and a large amount of greenhouse gases is generated during the ammonia production process.
In recent years, the preparation of ammonia gas by electrocatalysis at normal temperature and normal pressure by using nitrogen as a nitrogen source and water as a proton source has gradually become a focus of attention of researchers. The green synthesis method has the advantages of wide raw material source, no regional limitation on production devices, no generation of carbon-based byproducts and the like. At present, nitrogen reduction catalysts which have been widely reported mainly include metals, metal oxides, metal/carbon composites, and the like. However, due to the superior stability of the nitrogen-nitrogen triple bond, breaking the nitrogen-nitrogen triple bond requires overcoming a higher energy barrier; meanwhile, the reduction potentials of the nitrogen reduction reaction and the hydrogen evolution reaction are similar, so that the nitrogen reduction reaction and the hydrogen evolution reaction are in competition. This is why the synthesis of ammonia by the nitrogen reduction catalyst is inefficient.
Therefore, the design and development of the composite catalyst have rich active sites and improve the nitrogen adsorption, and are the premise and the key for improving the efficiency of synthesizing ammonia by electrocatalytic nitrogen reduction.
Disclosure of Invention
In order to solve the problems, the invention designs and synthesizes a class of ABO by means of an improved liquid phase method and a high-temperature roasting method3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material. The invention relates to a high-entropy perovskite Ba prepared by using an improved liquid phase method-high-temperature roasting methodx(FeCoNiZrY)0.2O3-δCompared with the traditional block material prepared by a high-temperature high-pressure method, the electrocatalysis material not only can expose more active sites, but also has the advantages of simple preparation process, low energy consumption, high uniformity and the like, and is expected to be used as an ideal electrocatalysis material for high-performance nitrogen reduction.
ABO3The high-entropy perovskite material has the advantages of low price, adjustable composition and environmentFriendly, special electronic structure and the like, and gradually receives wide attention. Particularly, the B site metal catalytic center of the high-entropy perovskite material has rich types and high structure tolerance, and the oxygen defect content of the high-entropy perovskite material can be regulated and controlled by regulating the stoichiometric ratio of A/B site elements, so that the optimal cost performance of the catalyst is achieved.
It is a first object of the present invention to provide an ammonia synthesis electrocatalyst, said catalyst being ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material; wherein, ABO3The metal in the A site in the type is Ba; the B site contains metals Fe, Co, Ni, Zr and Y, x is 0.9 and 1, and delta is more than 0 and less than 3.
In one embodiment of the invention, the atomic ratio of the metals is: ba: fe: co: ni: zr: and Y is 1: 0.2: 0.2: 0.2: 0.2: 0.2 or Ba: fe: co: ni: zr: y is 0.9: 0.2: 0.2: 0.2: 0.2: 0.2.
a second object of the present invention is to provide a method for preparing the above-mentioned ammonia synthesis electrocatalyst, comprising the steps of:
(1) dissolving polyacrylonitrile powder in N, N-dimethylformamide to obtain polyacrylonitrile solution, then carrying out electrostatic spinning, pre-oxidizing a membrane obtained by electrostatic spinning at high temperature, and then smashing and dispersing the pre-oxidized membrane in water to form dispersion liquid;
(2) dissolving barium salt, iron salt, cobalt salt, nickel salt, zirconium salt and yttrium salt in water to form aqueous solution; then adding a certain amount of glycol and citric acid to chelate metal salt to form a clear solution, adjusting the pH to 7-9 with ammonia water, heating and concentrating to form gel, adding the preoxidized polyacrylonitrile staple fiber dispersion liquid obtained in the step (1), continuously concentrating to form gel, and removing the solvent at high temperature to prepare precursor powder;
(3) roasting the precursor powder obtained in the step (2) to obtain ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material.
In one embodiment of the present invention, the polyacrylonitrile in the step (1) has a weight average molecular weight of 150000.
In one embodiment of the present invention, the concentration of the polyacrylonitrile solution in the step (1) is 0.08-0.12g/mL, preferably 0.1 g/mL.
In one embodiment of the present invention, the conditions for electrospinning in step (1) are 15-20kV, preferably 17kV, the distance between the receiver and the needle is 13cm, and the injection speed is 0.1 mm/min.
In one embodiment of the present invention, the pre-oxidation temperature in step (1) is 150 ℃ to 200 ℃ for 2-5h, preferably, the pre-oxidation temperature is 200 ℃ for 2 h.
In one embodiment of the present invention, the pre-oxidized film is broken in the step (1) by mechanical breaking, and the parameters of the mechanical breaking are as follows: 10000-15000 r/min, the time is 0.25-1h, and the preferable parameters of mechanical crushing are as follows: 13000 r/min for 0.5 h.
In one embodiment of the present invention, in the step (2), the cobalt salt includes: co (NO)3)2·6H2O, the nickel salt comprising: ni (NO)3)2·6H2O, the barium salt comprising: ba (NO)3)2The iron salt comprises: fe (NO)3)3·9H2O, the zirconium salt comprising: zr (NO)3)4·5H2O, the yttrium salt comprising: y (NO)3)3·6H2O。
In one embodiment of the present invention, when x is 0.9, the mass concentration of the barium salt in the aqueous solution in the step (2) is 4.0 to 5.0mg/mL (excluding 5.0 mg/mL); when x is 1, the mass concentration of the barium salt in the aqueous solution in the step (2) is 5.0-5.5 mg/mL.
In one embodiment of the present invention, the mass concentration of the cobalt salt in the aqueous solution in the step (2) is 1.0-1.5 mg/mL.
In one embodiment of the present invention, the mass concentration of the iron salt in the aqueous solution in the step (2) is 1.5-2.0 mg/mL.
In one embodiment of the present invention, the mass concentration of the nickel salt in the aqueous solution in the step (2) is 1.0 to 1.5 mg/mL.
In one embodiment of the present invention, the mass concentration of the zirconium salt in the aqueous solution in the step (2) is 1.5-2.0 mg/mL.
In one embodiment of the invention, the mass concentration of yttrium salt in the aqueous solution in the step (2) is 1.5-2.0 mg/mL.
In one embodiment of the present invention, the concentration of citric acid in the aqueous solution in the step (2) is 10.0-15.0mg/mL, and the concentration of ethylene glycol is 5.0-10.0 mg/mL.
In one embodiment of the present invention, the mass concentration of the pre-oxidized polyacrylonitrile staple fiber dispersion in the step (2) is 3.0-5.0mg/mL, preferably, the concentration is 4.5mg/L, and the addition amount is 5.0-10.0 mL.
In one embodiment of the present invention, the concentration in step (2) is performed at 60-100 ℃ for 10-24h, preferably, the concentration temperature is 80 ℃; the time is 24 h.
In one embodiment of the present invention, the temperature of the high temperature solvent removal in step (2) is 150 ℃ to 200 ℃, and the reaction time is 5-10h, preferably, the temperature is 200 ℃ and the reaction time is 5 h.
In one embodiment of the present invention, in the step (3), the calcination temperature is 800-.
In one embodiment of the present invention, in the step (2), the barium salt is Ba (NO)3)2When x is 0.9, the dosage is 470.4 mg; when x is 1.0, the amount is 522.7 mg; the cobalt salt being Co (NO)3)2·6H2O, the dosage is 116.4 mg; the nickel salt being Ni (NO)3)2·6H2O, the dosage is 116.3 mg; the iron salt being Fe (NO)3)3·9H2O, the dosage is 161.6 mg; the zirconium salt being Zr (NO)3)4·5H2O, 171.7 mg; yttrium salt being Y (NO)3)3·6H2O, 153.2 mg; when x is 0.9, the dosage of the citric acid is 1095.2 mg; the dosage of the ethylene glycol is 707.6 mg; when x is 1, the dosage of citric acid is 1152.8mg, and the dosage of ethylene glycol is 744.8 mg; the amount of water used was: 100 mL; pre-oxidized polyacrylonitrile dispersionsThe mass concentration is 4.5mg/L, and the dosage is 5 mL.
A third object of the present invention is to provide a method for producing ammonia gas, which employs the above catalyst or the catalyst produced by the above method as an electrocatalyst.
The fourth purpose of the invention is to apply the ammonia synthesis electrocatalyst described above to the field of ammonia gas preparation.
Compared with the prior art, the invention has the following remarkable advantages:
(1) the invention designs and synthesizes ABO with a porous structure by means of an improved liquid phase method and a high-temperature roasting method3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material;
(2) by adjusting the stoichiometric ratio of A/B site metals, the electronic structure change of five metals in the catalytic center and the change of the oxygen vacancy content are realized, the purposes of adjusting and optimizing the reduction performance of nitrogen are achieved, and the catalyst has excellent performance of converting nitrogen into ammonia by electrocatalysis;
(3) the material preparation process is simple, the repeated test is good, and the potential value of practical application is realized.
Drawings
FIG. 1 is ABO of the invention3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δSchematic diagram of electrocatalytic material and preparation method thereof.
FIG. 2 is an ABO prepared in the present invention3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δScanning Electron Microscope (SEM) pictures of electrocatalytic materials, wherein A, B corresponds to ABO with x ═ 0.9 and x ═ 1, respectively3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material.
FIG. 3 is an ABO prepared in the present invention3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn X-ray diffractometer (XRD) spectrum of the electrocatalytic material.
FIG. 4 is an ABO prepared in the present invention3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δX-ray energy spectrum analysis (EDX) and inductively coupled plasma spectroscopy (ICP) results of the electrocatalytic material, where A, B corresponds to ABO of X-0.9 and X-1, respectively3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δAn electrocatalytic material.
FIG. 5 is an ABO prepared in the present invention3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δX-ray photoelectron spectroscopy (XPS) curves of the electrocatalytic material.
FIG. 6 is an ABO prepared in the present invention3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δPerformance diagram of electrocatalytic nitrogen reduction to ammonia of electrocatalytic material.
Detailed Description
The invention will now be further illustrated by reference to specific examples, which are intended to be illustrative only and not to limit the scope of the invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
Example 1
1g of polyacrylonitrile powder was dissolved in 10mL of N, N-dimethylformamide, and electrostatic spinning was carried out with a spinning voltage of 17 kV. The resulting film was pre-oxidized at 200 ℃ for 2 hours. Finally, the pre-oxidized film was broken up at 13000 rpm for 0.5 hour to form a dispersion having a concentration of 4.5mg/mL in water.
470.4mg of Ba (NO) are added under stirring3)2116.4mg of Co (NO)3)2·6H2O, 116.3mg of Ni (NO)3)2·6H2O, 161.6mg Fe (NO)3)3·9H2O, 171.7mg of Zr (NO)3)4·5H2O, 153.2mg of Y (NO)3)3·6H2O was dissolved in 100mL of deionized water to give a clear and transparent solution. 1095.2mg of citric acid, 707.6mg of ethylene glycol are then added and the pH is adjusted to 9 with aqueous ammonia. The above solution is in 8After concentrating into gel at 0 ℃, pre-oxidized polyacrylonitrile dispersion liquid with mass concentration of 4.5mg/L is added, and the dosage is 5 mL. After mixing, the mixture is continuously concentrated to form a uniformly dispersed gel precursor. And heating the precursor to 200 ℃, and drying for 5h to obtain solid powder. Finally roasting for 5 hours at 1000 ℃ to obtain ABO3Type high entropy perovskite Ba0.9(FeCoNiZrY)0.2O3-δ。
The relevant process parameters in the electrochemical test method are as follows: 6mg of Bax(FeCoNiZrY)0.2O3-δThe resulting ink was mixed well with a solution of Nafion (5 wt%, 60. mu.L) in ethanol (1940. mu.L). Coating the above 40 μ L ink on 1 × 1cm-2And drying the carbon paper to prepare the electrode slice.
Detected by experiments, Ba0.9(FeCoNiZrY)0.2O3-δHas the nitrogen electroreduction performance, and the highest yield of ammonia and the highest Faraday efficiency are 24.37 mu g h in a certain overpotential range-1mg-1 catAnd 11.70%.
Example 2
1g of polyacrylonitrile powder was dissolved in 10mL of N, N-dimethylformamide, and electrostatic spinning was carried out with a spinning voltage of 17 kV. The resulting film was pre-oxidized at 200 ℃ for 2 hours. Finally, the pre-oxidized film was broken up at 13000 rpm for 0.5 hour to form a dispersion having a concentration of 4.5mg/mL in water.
Under stirring, 522.7mg of Ba (NO)3)2116.4mg of Co (NO)3)2·6H2O, 116.3mg of Ni (NO)3)2·6H2O, 161.6mg Fe (NO)3)3·9H2O, 171.7mg of Zr (NO)3)4·5H2O, 153.2mg of Y (NO)3)3·6H2O was dissolved in 100mL of deionized water to give a clear and transparent solution. 1152.8mg of citric acid, 744.8mg of ethylene glycol are then added and the pH is adjusted to 9 with aqueous ammonia. The solution was concentrated to a gel state at 80 ℃ and then 5mL of a pre-oxidized polyacrylonitrile dispersion solution was added at a mass concentration of 4.5 mg/L. After mixing, the mixture is continuously concentrated to form a uniformly dispersed gel precursor.And heating the precursor to 200 ℃, and drying for 5h to obtain solid powder. Finally roasting for 5 hours at 1000 ℃ to obtain ABO3Type high entropy perovskite Ba (FeCoNiZrY)0.2O3-δ。
Detected by the experiment described in example 1, Ba (FeCoNiZrY)0.2O3-δHas the nitrogen electroreduction performance, and the highest yield of ammonia and the highest Faraday efficiency are 16.11 mu g h in a certain overpotential range-1mg-1 catAnd 6.01%.
FIG. 1 is ABO3Type high entropy perovskite Ba (FeCoNiZrY)0.2O3-δThe preparation process is shown schematically.
Characterization of ABO obtained according to the invention using SEM, XRD, EDX, ICP, XPS, electrochemical workstation3Type high entropy perovskite Ba (FeCoNiZrY)0.2O3-δThe morphology and electronic structure of the electrocatalytic material and the performance of the electrocatalytic material used as a nitrogen reduction electrocatalyst have the following measurement results:
(1) SEM test results showed (see fig. 2): high entropy perovskite Bax(FeCoNiZrY)0.2O3-δIs lava-like morphology with pores of about 300nm in size.
(2) The XRD test results again show (see FIG. 3), that the high-entropy perovskite Ba isx(FeCoNiZrY)0.2O3-δThe crystal structure of (a) is a cubic phase structure, conforming to the general structure of perovskite materials.
(3) EDX and ICP analyses showed (see FIG. 4), high entropy perovskite Bax(FeCoNiZrY)0.2O3-δBa, Fe, Co, Ni, Zr, Y and O elements on the surface of the material are uniformly distributed, and the metal proportion ratio of the surface conforms to the charge ratio. Further illustrating the success of high entropy perovskite synthesis.
(4) XPS test results further prove that the high-entropy perovskite Ba isx(FeCoNiZrY)0.2O3-δThe surface of the material has Ba, Fe, Co, Ni, Zr, Y and O elements, as shown in figure 5.
(5) The electrochemical test result shows that the prepared ABO3Type high entropy perovskite Bax(FeCoNiZrY)0.2O3-δThe materials all have excellent nitrogenReduction performance. Wherein, when x is 0.9, Bax(FeCoNiZrY)0.2O3-δHas the highest ammonia yield and the highest Faraday efficiency of 24.37 mu g h respectively-1mg-1 catAnd 11.70%, see fig. 6.
Example 3
1.2g of polyacrylonitrile powder was dissolved in 10mL of N, N-dimethylformamide, and electrostatic spinning was carried out at a spinning voltage of 17 kV. The resulting film was pre-oxidized at 150 ℃ for 5 hours. Finally, the pre-oxidized film was broken up at 13000 rpm for 0.5 hour to form a dispersion having a concentration of 4.5mg/mL in water.
Under stirring, 522.7mg of Ba (NO)3)2116.4mg of Co (NO)3)2·6H2O, 116.3mg of Ni (NO)3)2·6H2O, 161.6mg Fe (NO)3)3·9H2O, 171.7mg of Zr (NO)3)4·5H2O, 153.2mg of Y (NO)3)3·6H2O was dissolved in 100mL of deionized water to give a clear and transparent solution. 1152.8mg of citric acid, 744.8mg of ethylene glycol are then added and the pH is adjusted to 9 with aqueous ammonia. The solution was concentrated to a gel state at 80 ℃ and then 5mL of a pre-oxidized polyacrylonitrile dispersion solution was added at a mass concentration of 4.5 mg/L. After mixing, the mixture is continuously concentrated to form a uniformly dispersed gel precursor. And heating the precursor to 150 ℃, and drying for 10h to obtain solid powder. Finally roasting for 5 hours at 850 ℃ to obtain ABO3Type high entropy perovskite Ba (FeCoNiZrY)0.2O3-δ。
Preparation of the resulting Ba (FeCoNiZrY)0.2O3-δHas a morphology similar to that of example 2 and has electrocatalytic properties similar to that of example 2.
Example 4
1g of polyacrylonitrile powder was dissolved in 10mL of N, N-dimethylformamide, and electrostatic spinning was carried out with a spinning voltage of 17 kV. The resulting film was pre-oxidized at 200 ℃ for 2 hours. Finally, the pre-oxidized film was broken up at 13000 rpm for 0.5 hour to form a dispersion having a concentration of 4.5mg/mL in water.
470.4mg of Ba (NO) are added under stirring3)2116.4mg of Co (NO)3)2·6H2O, 116.3mg of Ni (NO)3)2·6H2O, 161.6mg Fe (NO)3)3·9H2O, 171.7mg of Zr (NO)3)4·5H2O, 153.2mg of Y (NO)3)3·6H2O was dissolved in 100mL of deionized water to give a clear and transparent solution. 1152.8mg of citric acid, 744.8mg of ethylene glycol are then added and the pH is adjusted to 9 with aqueous ammonia. The solution was concentrated to a gel state at 80 ℃ and then 10mL of a pre-oxidized polyacrylonitrile dispersion solution was added at a mass concentration of 4.5 mg/L. After mixing, the mixture is continuously concentrated to form a uniformly dispersed gel precursor. And heating the precursor to 200 ℃, and drying for 5h to obtain solid powder. Finally roasting at 1100 ℃ for 5h to obtain ABO3Type high entropy perovskite Ba0.9(FeCoNiZrY)0.2O3-δ。
Prepared Ba0.9(FeCoNiZrY)0.2O3-δHas a morphology similar to that of example 1 and has electrocatalytic properties similar to that of example 1.
Comparative example 1
When the concentration of polyacrylonitrile in step 1 is further increased, or the calcination temperature in step 2 is lower than 800 ℃, impurities of the high-entropy perovskite phase are caused.
Comparative example 2
When step (1) is not present, the remaining operating parameters are the same as those in example 1 (no pre-oxidized polyacrylonitrile staple fiber dispersion is added in step (2)), and Ba is preparedx(FeCoNiZrY)0.2O3-δThe electrocatalytic material does not have the morphology structure shown in the attached figure 2, and the electrocatalytic performance is poor.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.