Preparation method of high-entropy pyrochlore type catalytic material with diatom shell morphology

Abstract

The present application relates to the field of new materials, and aims to provide a preparation method of high-entropy pyrochlore type catalytic material with diatom shell morphology.The method comprises the following steps: immersing diatomite in a mixed solvent of triethanolamine and alcohol, adding a plurality of metal precursor solutions and L-lysine and ascorbic acid, uniformly mixing, then adding hydrogen peroxide and NaOH in sequence;after hydrothermal reaction, adding gluconic acid, and performing hydrothermal reaction again;burning the solid product to obtain the catalytic material.The present application adjusts the metal ion complexes in the precursor solution to make the dissociation degrees of the metal ions similar, so that the metal ions with large electronegativity difference have good cooperativity in the subsequent nucleation and crystallization process, thereby improving the uniformity of the final product and reducing the formation temperature of the pyrochlore phase;the formation temperature of the pyrochlore is reduced through secondary hydrothermal reconstruction crystallization;therefore, the present application can save the production cost of the catalytic material compared with the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new materials, and in particular to a preparation method of high-entropy pyrochlore-type (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu 0.2 ,Ag 0.1 )O7 catalytic material with diatom frustule morphology. BACKGROUND

[0002] Diatomite is a natural hierarchical porous material with large pores, mesopores and micropores. At the same time, its reserves are also very considerable. Combined with its excellent hierarchical porosity and high cost performance brought by abundant reserves, diatomite is considered to be a very excellent catalytic carrier material, and has a wide application in many heterogeneous catalytic fields including catalytic hydrogenation, Fenton catalysis, heavy oil conversion, catalytic hydration, catalytic esterification, etc.

[0003] At present, due to the energy storage demand of new energy industries such as photovoltaic and wind power, the technology of hydrogen production by water electrolysis is also more and more widely valued, which converts the excess electrical energy into chemical energy of hydrogen for storage. Among the many water electrolysis reactors, the proton exchange membrane (PEM) water electrolysis technology is a new hydrogen production technology, which has the advantages of large current density and high energy efficiency. The anode region of PEM is a strong acid environment, and the performance of the anode oxygen evolution reaction (OER) catalyst is the main factor limiting the performance of the PEM electrolyzer. Improving the activity and stability of the acid OER catalyst is crucial to the development of the PEM electrolysis hydrogen production system. In the acid environment, the electrocatalytic oxygen evolution catalyst faces challenges, including slow reaction kinetics caused by water molecule dissociation and multi-step reaction, and stability problems caused by dissolution / corrosion. Therefore, it is necessary to develop an electrocatalyst that is both active and stable in an acid environment. Iridium oxide is the only commercially available OER electrocatalyst with acid stability, but the large-scale expansion of this noble metal requires more than 40 times the annual iridium production. Most transition metal-based materials can only effectively perform the OER process in alkaline electrolytes and are not stable in strong acid conditions. In this case, it is necessary to develop a cheap catalyst with high OER activity and acid resistance. High-entropy materials have higher stability due to high configurational entropy and more active site exposure due to high disorder, so high-entropy is an ideal strategy to achieve high stability and high activity of the catalyst.

[0004] By constructing high-entropy materials with a diatomaceous earth morphology, and combining the high activity and high stability of high-entropy materials with the hierarchical porous structure of diatomaceous earth, it is hoped that OER electrocatalysts with superior performance and greater stability under acidic conditions can be prepared. However, there are currently few reports on this topic. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a high-entropy pyrochlore-type catalytic material with a diatom shell morphology.

[0006] To solve the technical problem, the solution of the present invention is:

[0007] A method for preparing a high-entropy pyrochlore-type catalytic material with a diatom shell morphology is provided, comprising the following steps:

[0008] (1) Take Y(NO3)3, La(NO3)3, AgNO3, Sc(NO3)3, Bi(NO3)3 and NaNO3 as solutes in equimolar ratio; add the solutes to a mixed solvent of glycerol, isohexyl glycol, n-butanol and deionized water, and stir until completely dissolved to obtain solution one;

[0009] (2) Take RuCl3, SnCl4, Co(NO3)2, IrCl3, AgNO3, and Cu(NO3)2 as solutes in a molar ratio of 1:10:10:2:3:1; add the solutes to a mixed solvent of triethanolamine, methanol, and acetone, and stir until completely dissolved to obtain solution two;

[0010] (3) Add diatomaceous earth to solution two, with a mass ratio of diatomaceous earth to solution two of 0.05:0.95; after continuous stirring, a mixture one is obtained;

[0011] (4) Take mixture one and solution one at a mass ratio of 1.5:1, and add all of solution one at once while continuously stirring mixture one; continue stirring to obtain mixture two;

[0012] (5) Take L-lysine and ascorbic acid at a mass ratio of 0.05:0.95 and add them to mixture two. The mass ratio of the total mass of L-lysine and ascorbic acid to that of mixture two is 0.08:1. After stirring continuously for 20 to 40 minutes, add hydrogen peroxide all at once and stir continuously for another 20 to 40 minutes to obtain mixture three. The hydrogen peroxide accounts for 4% of the total mass of mixture three.

[0013] (6) Add NaOH to mixture three, with a mass ratio of NaOH to mixture three of 0.05:0.95; continue stirring for 1 to 3 hours to obtain mixture five;

[0014] (7) adding mixed solution five into the hydrothermal kettle with stirring, and adding 1% of diatomite in mass of the mixed solution five, and stirring;

[0015] (8) keeping stirring, sealing the hydrothermal kettle, and then heating to 90 DEG C, and keeping for 1-3 hours; then heating to 155 DEG C, and keeping for 1-3 hours; and then heating to 190 DEG C, and keeping for 12-24 hours; after stopping heating, cooling to room temperature, and obtaining mixture one;

[0016] (9) taking out the mixture one from the hydrothermal kettle, filtering, washing, and drying, and obtaining powder one;

[0017] (10) taking 1:10 of the powder one and 0.5wt% of the glucose acid aqueous solution according to mass ratio, and adding them into the hydrothermal kettle with stirring;

[0018] (11) keeping stirring, sealing the hydrothermal kettle, and heating to 240 DEG C, and keeping for 4-6 hours; after stopping heating, cooling to room temperature, and obtaining mixture two;

[0019] (12) taking out the mixture two from the hydrothermal kettle, filtering, washing, and drying, and obtaining powder two;

[0020] (13) placing the powder two obtained in step (12) into a tube furnace, heating to 550 DEG C, and keeping for 8-16 hours, and after natural cooling to room temperature, obtaining high-entropy pyrochlore type catalytic material with diatom shell morphology, and its molecular expression formula is (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu 0.2 ,Ag 0.1 )O7.

[0021] As a preferred scheme of the present application, in the solution one, the mass ratio of the total mass of solute to the mass of solvent is 7.5%; and in the solution two, the mass ratio of the total mass of solute to the mass of solvent is 13%.

[0022] As a preferred scheme of the present application, in the mixed solvent in step (1), the mass ratio of glycerol, isohexylene glycol, n-butanol and deionized water is 2:2:3:1.

[0023] As a preferred scheme of the present application, in the mixed solvent in step (2), the mass ratio of triethanolamine, methanol and acetone is 1:3:4.

[0024] As a preferred scheme of the present application, in the step (3), the time of continuous stirring is 1-3 hours.

[0025] As a preferred scheme of the present application, in the step (4), the time of continuous stirring after the solution is added into the mixed solution is 2-6 hours.

[0026] As a preferred scheme of the present application, in the step (7), the stirring rate is kept at 300 rpm, and the stirring time is 10-20 minutes.

[0027] As a preferred scheme of the present application, in the step (9), the drying is performed after the washing with anhydrous ethanol for three times; the drying temperature is 60 DEG C, and the drying time is 24 hours.

[0028] As a preferred scheme of the present application, in the step (10), the stirring rate is kept at 300 rpm, and the stirring time is 10-20 minutes.

[0029] As a preferred scheme of the present application, in the step (12), the drying is performed after the washing with deionized water for three times; the drying temperature is 80 DEG C, and the drying time is 24 hours.

[0030] Invention principle description:

[0031] The present application fully utilizes the advantages of high-entropy material and diatom biological structure by constructing high-entropy catalytic material with diatom shell biological structure, and obtains catalytic material suitable for electrocatalytic oxygen evolution under acidic conditions with high stability and high activity.

[0032] 1. Compared with conventional catalytic materials, the high-entropy catalytic material has better structure and chemical stability due to the entropy stabilization principle, and the structure distortion caused by high entropy can make the catalytic material have more active sites. The biological structure of diatom shell has hierarchical porous characteristics, and is very beneficial to the mass transfer process in the chemical reaction catalytic process. Therefore, the catalytic material prepared in the present application has better stability and higher activity.

[0033] 2、The application can prepare high-performance materials by increasing the element types in the compound to increase the ideal mixing entropy, and using the "cocktail effect" brought by the increase in entropy, but the ideal mixing entropy (i.e. the number of element types and the number of element types used) required to increase for different material systems and the performance to be improved is threshold, and there is no uniform standard, which needs to be optimized for different material systems combined with theory and experiment. The introduction of Na and Bi into the A site of pyrochlore, combined with high entropy of the A site, can effectively modulate the electronic structure of the lanthanide elements in the A site of pyrochlore, so that the originally localized f orbit of the lanthanide elements in the A site of pyrochlore is more expanded, thereby promoting the A site of pyrochlore to participate in the electrochemical reaction process and increasing the catalytic activity. In addition, the ionic radius of Y and Sc elements is also smaller than that of La, which is beneficial to shrink the size of the tetrahedron, and further improve the orbital expansion. In the B site of pyrochlore, silicon elements are creatively introduced, which is beneficial to break the octahedral configuration of the conventional B site, on the one hand, the octahedral structure of the original B site is deformed greatly, and more active sites are exposed, on the other hand, the d orbit of the other metal elements in the B site is also modulated to be more expanded. The introduction of Ag and Cu elements into the B site of pyrochlore can improve the conductivity of the material, thereby being beneficial to the improvement of the electrocatalytic performance.

[0034] 3、The application can realize the purpose of adjusting the structure and composition by mixing a plurality of alcohol reagents, so that the mixed solvent has the optimal solubility parameter and the ion product constant of the precursor metal salt in the solution is adjusted.

[0035] 4、L-lysine and ascorbic acid have the ability to form complexes with metal oxygen ions, and the addition of L-lysine and ascorbic acid during preparation can effectively adjust the deposition and reaction speed of each element, which is beneficial to the formation of a more uniform element mixture precursor; hydrogen peroxide has the function of destroying metal oxygen bridging polymerization, which is beneficial to breaking the bridging of single metal oxide in the formation process, so that the element distribution in the obtained precursor is more uniform. NaOH provides anions for the formation of the precursor; and the addition of gluconic acid is beneficial to further optimize the microstructure of the precursor before calcination, that is, through the process of dissolution-nucleation again, the uniformity of element distribution is further improved.

[0036] 5、The application can provide a precursor with a high degree of uniformity of element distribution for the formation of high-entropy pyrochlore structure by the process of improving the uniformity of element distribution through multiple hydrothermal processes.

[0037] 6、The pyrochlore structure itself has high resistance to acidic conditions, and the stabilization effect brought by high entropy further improves the stability of the pyrochlore under acidic conditions.

[0038] 7. This invention fully utilizes the hierarchical porous characteristics and orderly pore arrangement of the shell-like biological microparticle structure in diatomaceous earth, which is beneficial to the mass transfer process during chemical reaction catalysis.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. This invention optimizes the metal ion coordination process. By adjusting the complexes of each metal ion in the precursor solution, the degree of dissociation of each metal ion is made similar. This allows the metal ions at the A-site and B-site of pyrochlore, which have a large difference in electronegativity, to have better synergy in the subsequent nucleation and crystallization process, thereby improving the uniformity of the final product and reducing the formation temperature of the pyrochlore phase.

[0041] 2. This invention reduces the formation temperature of pyrochlore by secondary hydrothermal reconstruction crystallization; therefore, it can save on the production cost of catalytic materials compared with the prior art. Attached Figure Description

[0042] Figure 1 This is an electron microscope image of the high-entropy pyrochlore-type catalyst material prepared in Example 1 of the present invention. Detailed Implementation

[0043] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0044] In the following examples, Y(NO3)3, La(NO3)3, AgNO3, Sc(NO3)3, Bi(NO3)3, NaNO3, NaOH, RuCl3, SnCl4, Co(NO3)2, IrCl3, AgNO3, and Cu(NO3)2 are all powdered solids. Glycerol, isohexyl glycol, n-butanol, triethanolamine, methanol, acetone, hydrogen peroxide, gluconic acid, L-lysine, and ascorbic acid are all commercial reagents.

[0045] Part One: Examples of Implementation of the Invention

[0046] Example 1

[0047] (1) Take Y(NO3)3, La(NO3)3, AgNO3, Sc(NO3)3, Bi(NO3)3, and NaNO3 as solutes in equimolar ratio; add the solutes to a mixed solvent of glycerol, isohexanediol, n-butanol, and deionized water in a mass ratio of 2:2:3:1, with the total mass of solute to the mass ratio of solvent being 7.5%, and stir until completely dissolved to obtain solution one;

[0048] (2) Take RuCl3, SnCl4, Co(NO3)2, IrCl3, AgNO3, Cu(NO3)2 as solutes in a molar ratio of 1:10:10:2:3:1; add the solutes into a mixed solvent mixed by triethanolamine, methanol and acetone in a mass ratio of 1:3:4, the total mass of the solutes to the mass of the solvent is 13%, stir until completely dissolved to obtain solution two;

[0049] (3) Add diatomite into solution two and continuously stir for 1 hour to obtain mixture one, the mass ratio of diatomite to solution two is 0.05:0.95.

[0050] (4) Continuously stir mixture one and add all solution one at one time during the stirring process, and stir for another 2 hours to obtain mixture two. The mass ratio of mixture one to solution one is 1.5:1.

[0051] (5) Add L-lysine and ascorbic acid into mixture two, the mass ratio of L-lysine to ascorbic acid is 0.05:0.95, the total mass of L-lysine and ascorbic acid to the mass of mixture two is 0.08:1, continuously stir for 20 minutes; then add 4% hydrogen peroxide based on the total mass at one time, and continuously stir for another 20 minutes to obtain mixture three;

[0052] (6) Add NaOH into mixture three, the mass ratio of NaOH to mixture three is 0.05:0.95, continuously stir for 1 hour to obtain mixture five;

[0053] (7) Add mixture five into a hydrothermal kettle with stirring, then add 1% diatomite based on the mass of mixture, start stirring, and keep the stirring rate at 300 revolutions per minute, and stir for 10 minutes;

[0054] (8) Keep stirring, seal the hydrothermal kettle, heat to 90°C, and keep the temperature for 1 hour; then heat to 155°C, and keep the temperature for 1 hour; then heat to 190°C, and keep the temperature for 12 hours; stop heating, and cool to room temperature to obtain mixture one;

[0055] (9) Take mixture one out of the hydrothermal kettle, filter and wash with anhydrous ethanol for three times, and obtain powder one after drying; the drying temperature is 60°C, and the drying time is 24 hours;

[0056] (10) Mix powder one with 0.5wt% aqueous solution of gluconic acid, add into a hydrothermal kettle with stirring, start stirring, and keep the stirring rate at 300 revolutions per minute, and stir for 10 minutes, the mass ratio of powder one to aqueous solution of gluconic acid is 1:10;

[0057] (11) keep stirring, seal the hydrothermal kettle, and heat to 240℃, and keep for 4 hours; after stopping heating, cool to room temperature to obtain mixture two;

[0058] (12) take mixture two out of the hydrothermal kettle, filter and wash with deionized water three times, and obtain powder two after drying; the temperature during drying is 80℃, and the time is 24 hours;

[0059] (13) place powder two obtained in step (12) in a tube furnace, heat to 550℃, keep for 8 hours, and naturally cool to room temperature to obtain high-entropy pyrochlore type catalytic material with diatom shell morphology.

[0060] After inductively coupled plasma mass spectrometry (ICP-MS) detection, it is confirmed that the molecular expression of the catalytic material is: (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu 0.2 ,Ag 0.1 )O7.

[0061] Take 5 milligrams of high-entropy pyrochlore type (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu 0.2 ,Ag 0.1 )O7 catalyst with diatom shell morphology, add 500 microliters of ethanol, and then add 50 microliters of nafion solution, and ultrasonic for 1 hour to prepare a dispersion. Take 50 microliters of the dispersion and drop it on a 5mm*5mm carbon paper to prepare a working electrode after drying, and the catalyst loading is 1mg / cm 2 . A three-electrode electrolytic cell is used, a 1*1cm platinum electrode is used as a counter electrode, an Ag / AgCl electrode is used as a reference electrode, and 0.5M H2SO4 aqueous solution is used as an electrolyte, and the polarization curve is tested in the range of 0-1V.

[0062] After testing, the potential required to reach a current density of 10m A / cm 2 is 220mV.

[0063] Example 2

[0064] (1) Take Y(NO3)3, La(NO3)3, AgNO3, Sc(NO3)3, Bi(NO3)3, NaNO3 as solutes in equal molar ratio; add the solutes into a mixed solvent mixed by glycerol, isohexanediol, n-butanol and deionized water in a mass ratio of 2:2:3:1, the mass ratio of total mass of solutes to solvent is 7.5%, stir until completely dissolved to obtain solution one;

[0065] (2) Take RuCl3, SnCl4, Co(NO3)2, IrCl3, AgNO3, Cu(NO3)2 as solutes in a molar ratio of 1:10:10:2:3:1; add the solutes into a mixed solvent mixed by triethanolamine, methanol and acetone in a mass ratio of 1:3:4, the mass ratio of total mass of solutes to solvent is 13%, stir until completely dissolved to obtain solution two;

[0066] (3) Add diatomite into solution two and continuously stir for 3 hours to obtain mixed solution one, the mass ratio of diatomite to solution two is 0.05:0.95.

[0067] (4) Continuously stir mixed solution one and add all solution one at one time during the stirring process, and stir for another 6 hours to obtain mixed solution two. The mass ratio of mixed solution one to solution one is 1.5:1.

[0068] (5) Add L-lysine and ascorbic acid into mixed solution two, the mass ratio of L-lysine to ascorbic acid is 0.05:0.95, the mass ratio of total mass of L-lysine and ascorbic acid to mixed solution two is 0.08:1, continuously stir for 40 minutes; then add 4% hydrogen peroxide based on total mass at one time, and continuously stir for another 40 minutes to obtain mixed solution three;

[0069] (6) Add NaOH into mixed solution three, the mass ratio of NaOH to mixed solution three is 0.05:0.95, continuously stir for 3 hours to obtain mixed solution five;

[0070] (7) Add mixed solution five into a hydrothermal kettle with stirring, then add 1% diatomite based on the mass of mixed solution, start stirring, and keep the stirring rate at 300 revolutions per minute, and stir for 20 minutes;

[0071] (8) Keep stirring, seal the hydrothermal kettle, heat to 90℃, and keep the temperature for 3 hours; then heat to 155℃, and keep the temperature for 3 hours; then heat to 190℃, and keep the temperature for 24 hours; stop heating, and cool to room temperature to obtain mixture one;

[0072] (9) Take mixture one out of the hydrothermal kettle, filter and wash with anhydrous ethanol for three times, and obtain powder one after drying; the drying temperature is 60℃, and the drying time is 24 hours;

[0073] (10) The powder I is mixed with 0.5wt% of a glucose acid aqueous solution, and is added to a hydrothermal kettle with stirring. The stirring is started, and the stirring rate is kept at 300 revolutions / minute. The stirring is continued for 20 minutes. The mass ratio of the powder I to the glucose acid aqueous solution is 1:10;

[0074] (11) The stirring is kept, the hydrothermal kettle is sealed, and the temperature is raised to 240°C. The temperature is kept for 6 hours. After the heating is stopped, the temperature is cooled to room temperature to obtain a mixture II;

[0075] (12) The mixture II is taken out of the hydrothermal kettle, is filtered, and is washed with deionized water three times. After drying, a powder II is obtained. The drying temperature is 80°C, and the drying time is 24 hours;

[0076] (13) The powder II obtained in step (12) is placed in a tube furnace, and the temperature is raised to 550°C. The temperature is kept for 16 hours. After natural cooling to room temperature, a high-entropy pyrochlore type catalytic material with diatom shell morphology is obtained.

[0077] The catalytic material is detected by inductively coupled plasma mass spectrometry (ICP-MS), and the molecular expression formula of the catalytic material is confirmed as: (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu 0.2 ,Ag 0.1 )O7.

[0078] 5 milligrams of the high-entropy pyrochlore type (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu 0.2 ,Ag 0.1 )O7 catalyst with diatom shell morphology is taken, is added to 500 microliters of ethanol, and then 50 microliters of a nafion solution is added. An ultrasonic treatment is performed for 1 hour to prepare a dispersion liquid. 50 microliters of the dispersion liquid is dropped on a 5mm*5mm carbon paper to prepare a working electrode after air drying. The catalyst loading is 1mg / cm 2The polarization curve was tested in the range of 0-1V by using a three-electrode electrolytic cell, a 1*1cm platinum electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and 0.5M H2SO4 aqueous solution as the electrolyte.

[0079] It was tested that the current density reached 10m A / cm 2 The potential required for the current density was 181mV.

[0080] Example 3

[0081] (1) Y(NO3)3, La(NO3)3, AgNO3, Sc(NO3)3, Bi(NO3)3, and NaNO3 were taken as solutes in an equimolar ratio; the solutes were added into a mixed solvent prepared by mixing glycerol, isohexyl alcohol, n-butanol, and deionized water in a mass ratio of 2:2:3:1, and the mass ratio of the total mass of the solutes to the mass of the solvent was 7.5%; after stirring until complete dissolution, solution one was obtained;

[0082] (2) RuCl3, SnCl4, Co(NO3)2, IrCl3, AgNO3, and Cu(NO3)2 were taken as solutes in a molar ratio of 1:10:10:2:3:1; the solutes were added into a mixed solvent prepared by mixing triethanolamine, methanol, and acetone in a mass ratio of 1:3:4, and the mass ratio of the total mass of the solutes to the mass of the solvent was 13%; after stirring until complete dissolution, solution two was obtained;

[0083] (3) Diatomite was added into solution two, and continuous stirring was performed for 2 hours to obtain mixed solution one, and the mass ratio of diatomite to solution two was 0.05:0.95.

[0084] (4) Mixed solution one was continuously stirred, and all of solution one was added at one time during the stirring process, and stirring was performed for another 4 hours to obtain mixed solution two. The mass ratio of mixed solution one to solution one was 1.5:1.

[0085] (5) L-lysine and ascorbic acid were added into mixed solution two, the mass ratio of L-lysine to ascorbic acid was 0.05:0.95, the mass ratio of the total mass of L-lysine and ascorbic acid to mixed solution two was 0.08:1, and continuous stirring was performed for 30 minutes; 4% of hydrogen peroxide based on the total mass was added at one time, and continuous stirring was performed for another 30 minutes to obtain mixed solution three;

[0086] (6) NaOH was added into mixed solution three, the mass ratio of NaOH to mixed solution three was 0.05:0.95, and continuous stirring was performed for 2 hours to obtain mixed solution five;

[0087] (7) Mixed solution five was added into a water heating kettle with stirring, and 1% of diatomite based on the mass of mixed solution was added, stirring was started, and the stirring rate was maintained at 300 revolutions / minute, and stirring was performed for 15 minutes;

[0088] (8) keep stirring, seal the autoclave, and heat to 90°C, keep for 2 hours; then heat to 155°C, keep for 2 hours; then heat to 190°C, keep for 18 hours; after stopping heating, cool to room temperature to obtain mixture one;

[0089] (9) take mixture one out of the autoclave, filter and wash with anhydrous ethanol for three times, and obtain powder one after drying; the temperature for drying is 60°C, and the time is 24 hours;

[0090] (10) mix powder one with 0.5wt% glucose acid aqueous solution, and add to the stirred autoclave, start stirring, keep the stirring rate at 300 revolutions per minute, stir for 15 minutes, and the mass ratio of powder one to glucose acid aqueous solution is 1:10;

[0091] (11) keep stirring, seal the autoclave, and heat to 240°C, keep for 5 hours; after stopping heating, cool to room temperature to obtain mixture two;

[0092] (12) take mixture two out of the autoclave, filter and wash with deionized water for three times, and obtain powder two after drying; the temperature for drying is 80°C, and the time is 24 hours;

[0093] (13) place powder two obtained in step (12) in a tube furnace, heat to 550°C, keep for 12 hours, and cool to room temperature naturally to obtain high-entropy pyrochlore type catalytic material with diatom shell morphology.

[0094] After inductively coupled plasma mass spectrometry (ICP-MS) detection, it is confirmed that the molecular expression of the catalytic material is: (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu 0.2 ,Ag 0.1 )O7.

[0095] Take 5 milligrams of high-entropy pyrochlore type (Y 0.4 ,La 0.4 ,Bi 0.4 ,Na 0.4 ,Sc 0.4 )(Ru 0.1 ,Si 0.1 ,Sn 0.6 ,Co 0.7 ,Ir 0.2 ,Cu0.2 ,Ag 0.1 )O7 catalyst was added into 500 microliters of ethanol, and 50 microliters of nafion solution was added, and ultrasonic was performed for 1 hour to prepare a dispersion liquid. 50 microliters of the dispersion liquid was dropped on a 5mm*5mm carbon paper, and after being dried, a working electrode was prepared, and the catalyst loading was 1mg / cm 2 A three-electrode electrolytic cell was used, a 1*1cm platinum electrode was used as a counter electrode, an Ag / AgCl electrode was used as a reference electrode, and 0.5M H2SO4 aqueous solution was used as an electrolyte, and a polarization curve was tested in a range of 0-1V.

[0096] It was tested that a potential required to reach a current density of 10m A / cm 2 was 197mV.

[0097] It was observed by electron microscopy that the element proportions of the materials obtained in the above examples 1-3 were the same, and all had the macrostructure of diatomite. Figure 1 An electron microscope photograph of the product obtained in example 1 is shown in FIG. 2, and it can be seen that the product particles basically retain the shell-like original morphology of diatomite. Due to the different control parameters in the preparation processes of examples 1-3, there are slight performance differences due to reasons such as grain size and content of pyrochlore phase, so that they exhibit different electrocatalytic properties.

[0098] The second part is a comparative example of the present application

[0099] Comparative example 1.1

[0100] In comparative example 1.1, the preparation process of the catalytic material is the same as that of example 1, and the only difference is the difference in the added components; compared with the product of example 1, the product of comparative example 1.1 correspondingly lacks Na element.

[0101] Comparative example 1.2

[0102] In comparative example 1.2, the preparation process of the catalytic material is the same as that of example 1, and the only difference is the difference in the added components; compared with the product of example 1, the product of comparative example 1.2 correspondingly lacks Na and Bi elements.

[0103] Comparative example 1.3

[0104] In comparative example 1.2, the preparation process of the catalytic material is the same as that of example 1, and the only difference is the difference in the added components; compared with the product of example 1, the product of comparative example 1.3 correspondingly lacks Y and Sc elements.

[0105] Comparative example 1.4

[0106] In Comparative Example 1.2, the preparation process of the catalytic material is the same as that of Example 1, and the only difference is the difference in the added components; compared with the product of Example 1, the product of Comparative Example 1.4 is correspondingly lack of Si element.

[0107] Comparative Example 1.5

[0108] In Comparative Example 1.2, the preparation process of the catalytic material is the same as that of Example 1, and the only difference is the difference in the added components; compared with the product of Example 1, the product of Comparative Example 1.5 is correspondingly lack of Ag and Cu elements.

[0109] The same test method as in the examples of the present application is used for the above five comparative examples, and the overpotential value required to reach 10 mA / cm 2 current density is taken as the comparison object.

[0110] For easy reading, the product molecular formula and overpotential value of each comparative example are listed in the form of the following table.

[0111]

[0112] From the test data of Comparative Examples 1.1-1.5d, it can be seen that the overpotential of the catalytic material of the five comparative examples required to reach 10 mA / cm 2 current density is significantly higher than that of the product of the present application. It can be seen that reducing the number of elements on the basis of the product of the present application will lead to the deterioration of the final performance of the product.

[0113] Comparative Example 2

[0114] Referring to the description of the patent document “Preparation of diatomite limited cobalt platinum-based composite material and its application in electrocatalytic oxygen reduction and oxygen evolution reaction” (CN107342425A), diatomite, CoCl2·6H2O and H2PtCl6·6H2O are used as main raw materials to prepare diatomite (DTM) limited cobalt platinum-based composite electrode material.

[0115] Then, referring to the operation described in Example 1, the electrode material is processed into a working electrode, which is then used to build a three-electrode electrolysis cell, and the polarization curve is tested, and the potential required to reach 10 mA / cm 2 current density is 396 mV.

[0116] Comparative Example 3

[0117] Referring to the description of the journal document “Study on the performance of diatomite supported metal catalyst for hydrogen production”, diatomite and cobalt nitrate are used as main raw materials to prepare diatomite supported with metal cobalt and form an electrode material.

[0118] Then, according to the operation described in Example 1, the electrode material was processed into a working electrode and then used to build a three-electrode electrolysis cell, and the polarization curve was tested to reach 10 m A / cm 2 The potential required for the current density was 377 mV.

[0119] Comparative Example 4

[0120] According to the description in the patent document "A Catalyst and a Preparation Method Thereof" (CN115970688A), an IrO2 and pyrochlore La2Ir2O7 crystal compound were prepared to form an electrode material.

[0121] Then, according to the operation described in Example 1, the electrode material was processed into a working electrode and then used to build a three-electrode electrolysis cell, and the polarization curve was tested to reach 10 m A / cm 2 The potential required for the current density was 267 mV.

[0122] Comparative Example 5

[0123] According to the description in the journal document "Mitigation of RuO6 octahedron distortion by enhanced A-site electronegativity in pyrochlore for acidic water oxidation", a pyrochlore Ho2Ru2O7 electrode material was prepared.

[0124] Then, according to the operation described in Example 1, the electrode material was processed into a working electrode and then used to build a three-electrode electrolysis cell, and the polarization curve was tested to reach 10 m A / cm 2 The potential required for the current density was 255 mV.

[0125] From the test data of Comparative Examples 2-5, it can be seen that the catalytic material prepared by the preparation method of the present application has better electrocatalytic performance under acidic conditions than the catalyst prepared by the prior art.

[0126] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various modifications or modifications within the scope of the claims, which does not affect the essential content of the present application.

Claims

1. A method for preparing a high-entropy pyrochlore-type catalytic material with a diatom shell morphology, characterized in that, Includes the following steps: (1) Take Y(NO3)3, La(NO3)3, AgNO3, Sc(NO3)3, Bi(NO3)3 and NaNO3 as solutes in equimolar ratio; add the solutes to a mixed solvent of glycerol, isohexyl glycol, n-butanol and deionized water, and stir until completely dissolved to obtain solution one; (2) Take RuCl3, SnCl4, Co(NO3)2, IrCl3, AgNO3, and Cu(NO3)2 as solutes in a molar ratio of 1:10:10:2:3:1; add the solutes to a mixed solvent of triethanolamine, methanol, and acetone, and stir until completely dissolved to obtain solution two; (3) Add diatomaceous earth to solution two, with a mass ratio of diatomaceous earth to solution two of 0.05:0.95; after continuous stirring, a mixture one is obtained; (4) Take mixture one and solution one at a mass ratio of 1.5:1, and add all of solution one at once while continuously stirring mixture one; continue stirring to obtain mixture two; (5) Take L-lysine and ascorbic acid at a mass ratio of 0.05:0.95 and add them to mixture two. The mass ratio of the total mass of L-lysine and ascorbic acid to that of mixture two is 0.08:

1. After stirring continuously for 20 to 40 minutes, add hydrogen peroxide all at once and stir continuously for another 20 to 40 minutes to obtain mixture three. The hydrogen peroxide accounts for 4% of the total mass of mixture three. (6) Add NaOH to mixture three, with a mass ratio of NaOH to mixture three of 0.05:0.95; continue stirring for 1 to 3 hours to obtain mixture five; (7) Add the mixture five to a hydrothermal reactor with a stirrer, then add diatomaceous earth accounting for 1% of the mass of the mixture five, and stir. (8) Seal the hydrothermal reactor while stirring, then heat to 90°C and hold for 1-3 hours; then heat to 155°C and hold for 1-3 hours; then heat to 190°C and hold for 12-24 hours; after stopping heating, cool to room temperature to obtain mixture one; (9) Take the mixture one out of the hydrothermal reactor, filter, wash and dry it to obtain powder one; (10) Take 1:10 powder and 0.5wt% gluconic acid aqueous solution by mass ratio, add them to a hydrothermal reactor with stirring, and stir. (11) While stirring, seal the hydrothermal reactor, heat it to 240°C, and keep it at that temperature for 4 to 6 hours; after stopping the heating, cool it to room temperature to obtain mixture two; (12) Take the mixture 2 out of the hydrothermal reactor, filter, wash and dry it to obtain powder 2; (13) Place the powder obtained in step (12) into a tube furnace, heat it to 550°C, hold it at that temperature for 8–16 hours, and then allow it to cool naturally to room temperature to obtain a high-entropy pyrochlore-type catalyst with a diatom shell morphology. Its molecular expression is (Y 0.4 ,La 0.4 ,Bi 0.4 Na 0.4 ,Sc 0.4 (Ru) 0.1 Si 0.1 Sn 0.6 Co 0.7 ,Ir 0.2 Cu 0.2 Ag 0.1 )O7.

2. The method according to claim 1, characterized in that, In solution one, the total mass ratio of solute to solvent is 7.5%; in solution two, the total mass ratio of solute to solvent is 13%.

3. The method according to claim 1, characterized in that, In the mixed solvent of step (1), the mass ratio of glycerol, isohexyl glycol, n-butanol and deionized water is 2:2:3:

1.

4. The method according to claim 1, characterized in that, In the mixed solvent of step (2), the mass ratio of triethanolamine, methanol and acetone is 1:3:

4.

5. The method according to claim 1, characterized in that, In step (3), the stirring time is 1 to 3 hours.

6. The method according to claim 1, characterized in that, In step (4), after adding solution one to mixture one, the stirring time is continued for 2 to 6 hours.

7. The method according to claim 1, characterized in that, In step (7), the stirring rate is maintained at 300 rpm for 10 to 20 minutes.

8. The method according to claim 1, characterized in that, In step (9), the product is washed three times with anhydrous ethanol and then dried; the drying temperature is 60°C and the drying time is 24 hours.

9. The method according to claim 1, characterized in that, In step (10), the stirring rate is maintained at 300 rpm for 10 to 20 minutes.

10. The method according to claim 1, characterized in that, In step (12), the product is washed three times with deionized water and then dried; the drying temperature is 80°C and the drying time is 24 hours.

Images