Application of cobalt-based perovskite catalyst in hydrogen production of alkaline anion exchange membrane electrolytic cell
The cobalt-based perovskite catalyst Ba2Co2-xMxO6 addresses the limitations of scarce and costly OER catalysts by enhancing oxygen evolution reaction efficiency and stability in alkaline electrolysis, offering a cost-effective solution with reduced noble metal content.
Patent Information
- Application Number
- CN202510715870.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-07-11
AI Technical Summary
Current OER catalysts, such as IrO2 and RuO2, are limited by their scarcity and high cost, necessitating the development of a more cost-effective and active catalyst for the oxygen evolution reaction in alkaline electrolysis.
A novel cobalt-based perovskite catalyst, Ba2Co2-xMxO6 (where M = Fe, Ni, Ru, Ir) is synthesized via a high-pressure solid-state method and applied in an alkaline ion exchange membrane electrolyzer, enhancing the catalytic activity of the oxygen evolution reaction.
The Ba2Co2-xMxO6 catalyst demonstrates superior OER performance with reduced noble metal usage, achieving low overpotential and high stability, significantly improving oxygen production efficiency.
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Figure CN120291128A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the application of a cobalt-based perovskite catalyst in hydrogen production by an alkaline anion exchange membrane electrolyzer, belonging to the technical field of electrocatalytic oxygen evolution. Background Art
[0002] To meet the energy demands of modern society, it is particularly important to seek sustainable, clean, and highly efficient energy production.
[0003] Electrolysis of water is a highly efficient and sustainable hydrogen generation pathway and is considered an effective method for future renewable energy production, storage, and use. Electrolysis of water consists of two half-reactions, namely hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode. Among them, HER is a two-electron transfer reaction while OER is a four-electron-proton coupled reaction, which requires higher energy (higher overpotential), making the oxygen evolution overpotential much higher than the theoretical decomposition voltage of water (1.23 V). The design and synthesis of highly efficient OER catalysts are the key to improving the energy efficiency of water electrolysis.
[0004] Currently, the most effective OER catalysts are oxides of noble metals iridium and ruthenium (such as IrO2 and RuO2, etc.), but their scarcity and high cost severely limit their large-scale application. Therefore, there is a need to provide catalysts with the characteristics of low noble metal usage and high activity. Perovskite oxides ABO 3-δ (A = alkaline earth metal or rare earth metal; B = transition metal) have attracted attention due to their high catalytic activity under alkaline conditions. It has been found that perovskite BaCoO3 has OER performance, but compared with noble metal catalysts, the performance of BaCoO3 still needs to be improved. By doping transition metals at the B-site of BaCoO3, the synergistic effect of Co and other transition metals can further improve the oxygen evolution activity.
[0005] Therefore, the present invention proposes to design a novel Ba2Co 2-x M x O6 (M = Fe, Ni, Ru, Ir) oxygen evolution electrode for alkaline water electrolysis for hydrogen production. Summary of the Invention
[0006] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art. The present invention provides the application of a cobalt-based perovskite catalyst in hydrogen production by an alkaline anion exchange membrane electrolyzer, which greatly improves the oxygen production mass activity.
[0007] To achieve the above purpose, the present invention adopts the following technical solutions:
[0008] 1. A cobalt-based perovskite catalyst, the molecular formula of which is Ba2Co 2-x Mx O6, M = Fe, Ni, Ru, Ir, where 0 < x < 2.
[0009] Preferably, x takes the values of 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75.
[0010] Preferably, the catalyst is prepared by the high-pressure solid-phase method.
[0011] 2. Application of the aforementioned cobalt-based perovskite catalyst in hydrogen production by electrolyzing water in an alkaline anion exchange membrane electrolyzer.
[0012] 3. Method for producing hydrogen using the aforementioned catalyst in an alkaline anion exchange membrane electrolyzer, the specific steps are as follows:
[0013] S1. First, mix and ball-mill the aforementioned catalyst, mixed solution I, and zirconia ceramic balls to obtain a ball-milled material.
[0014] S2. Mix the ball-milled material with carbon powder and dissolve it in mixed solution II, add a dispersant and perform rolling milling to obtain a slurry.
[0015] S3. Ultrasonically spray the slurry onto the anion exchange membrane to serve as the oxygen evolution anode, and prepare a slurry from commercial 20% Pt / C in the same manner as in step S1 and ultrasonically spray it onto the anion exchange membrane to serve as the hydrogen evolution cathode.
[0016] Preferably, in step S1, the composition of mixed solution I is ethanol and acetone, with a mass fraction accounting for 99% of the final slurry, and the added mass fraction of acetone is 50% of that of ethanol.
[0017] Preferably, in step S1, the diameter of the zirconia ceramic balls is 0.5 - 1 cm, and the mass ratio to the slurry is 1:1.5.
[0018] Preferably, in step S1, the rotational speed of the ball mill is 200 - 300 rpm, and the ball-milling time is 1 - 2 h. The purpose of ball-milling is to reduce the particle size of the material and give the material a larger active area.
[0019] Preferably, in step S2, the particle size of the ball-milled material is weighed to be 20 - 60 nm, and the total mass fraction of the ball-milled material and carbon powder accounts for 2% of the final slurry, where the ball-milled material accounts for no less than 40% of the mass of the two powders.
[0020] Preferably, in step S2, the composition of mixed solution II is deionized water and an anion exchange liquid, with a mass fraction accounting for 70% of the final slurry; the added mass fraction of deionized water is 80% of the two liquids.
[0021] Preferably, in step S2, the dispersant includes but is not limited to isopropanol, butanol, acetone, polypropylene, fish oil, etc., with a mass fraction accounting for 28% of the final slurry.
[0022] Preferably, in step S2, the tumbling and grinding time is 12 hours.
[0023] Preferably, in step S3, the anion exchange membrane is 3.5 * 3.5 cm 2 , and the spraying area on the membrane is 2 * 2 cm 2 ; After spraying, it is dried on a heating table at 70 °C for 12 h.
[0024] Preferably, in step S3, the brand of the anion exchange membrane is PiperIOn, and the model is A80-HC03.
[0025] Advantages of the present invention:
[0026] The present invention discloses an application of a cobalt-based perovskite catalyst in hydrogen production by an alkaline anion exchange membrane electrolyzer. The catalyst is Ba2Co 2-x M x O6 (M = Fe, Ni, Ru, Ir), (0 < x < 2) exhibits excellent catalytic activity for the oxygen evolution reaction (OER) at the anode of the anion exchange membrane electrolyzer. Ba2Co 2-x M x O6, the M transition metal and Co in it synergistically act and jointly reduce the reaction energy barrier of water electrolysis to promote the oxygen production performance. After being applied in the anion exchange membrane electrolyzer for water electrolysis, the oxygen production mass activity is greatly improved.
[0027] Among them, for the catalyst electrode with M being Ru and x = 1, Ba2CoRuO6 shows an ultra-low overpotential of 225 mV at a current density of 10 mA cm -2 and a stability of up to 170 hours at 500 mA cm -2 . In the synthesized perovskite catalyst, the synergistic effect between Ru and Co elements in the optimal sample Ba2CoRuO6 makes the material have more excellent catalytic OER activity than single materials, and reduces the amount of Ru used, saving the catalyst cost. Description of the drawings
[0028] Figure 1 It is the X-ray diffraction pattern of a perovskite Ba2CoRuO6 oxygen evolution catalyst provided in Examples 1, 2, and 3 of this application;
[0029] Figure 2 It is the morphology diagram of a perovskite Ba2CoRuO6 catalyst characterized by scanning electron microscopy provided in Example 1 of this application. The test voltage is 15 kV, and the magnification is 20000 times.
[0030] Figure 3High-angle annular dark-field scanning transmission electron micrograph of a perovskite Ba2CoRuO6 catalyst provided in Example 1 of this application.
[0031] Figure 4 Element distribution map of a perovskite Ba2CoRuO6 catalyst obtained by energy dispersive spectrometer provided in Example 1 of this application.
[0032] Figure 5 LSV curves of Example 1 of this application and commercial RuO2 obtained by using laboratory standard electrochemical tests.
[0033] Figure 6 Tafel slopes of Example 1 of this application and commercial RuO2 obtained by using laboratory standard electrochemical tests.
[0034] Figure 7 Schematic diagram of LSV of electrolytic cell performance of oxygen evolution electrodes provided in Examples 1, 2, and 3 of this application using 1M KOH electrolyte and a positive sweep rate of 5mV / s.
[0035] Figure 8 Stability test diagram of the perovskite Ba2CoRuO6 oxygen evolution electrode provided in Example 1 of this application in an anion exchange membrane electrolytic cell. Detailed implementation mode
[0036] The present invention will be further described below in conjunction with the drawings and embodiments. It should be noted that the following description is only for explaining the present invention and does not limit its content.
[0037] This embodiment provides a perovskite Ba2CoRuO6 oxygen evolution membrane electrode. The preparation method of the perovskite Ba2CoRuO6 oxygen evolution electrode includes the following steps:
[0038] 1) Weigh 50mg of Ba2CoRuO6 powder and place it in a ball milling jar. Add 5g of a mixed solution (ethanol: acetone = 3:5) and 3g of zirconia ceramic balls to the powder, and ball mill the mixed slurry at a rotation speed of 300r / min for 1h;
[0039] 2) After ball milling, suck the slurry into a beaker with a pipette and place it in an oven to dry at 60 degrees Celsius for 12h;
[0040] 3) Weigh the dried Ba2CoRuO6 powder and 50mg of carbon powder, and disperse them in a mixed solution containing 2.8g of deionized water, 0.7g of anion exchange, and 1.4g of isopropanol;
[0041] 4) Spray the above solution on a 3.5*3.5cm 2 anion exchange membrane as the anode using an ultrasonic sprayer, and the spraying area is 2*2cm 2;
[0042] 5) Prepare the commercial 20% Pt / C into a slurry following the above steps, and ultrasonically spray it on the same anion exchange membrane as the cathode;
[0043] 6) After spraying, dry it on a heating stage at 70 °C for 12 h to obtain the electrode of the anion exchange membrane electrolytic cell.
[0044] Example 2
[0045] This example provides a perovskite Ba2Co 0.5 Ru 1.5 O6 oxygen evolution membrane electrode. The preparation method of the perovskite Ba2Co 0.5 Ru 1.5 O6 oxygen evolution electrode comprises the following steps:
[0046] 1) Weigh 50 mg of Ba2Co 0.5 Ru 1.5 O6 powder and place it in a ball milling jar. Add 5 g of a mixed solution (ethanol:
[0047] acetone = 3:5) and 3 g of zirconia ceramic balls to the powder, and ball mill the mixed slurry at a rotation speed of 300 r / min for 1 h;
[0048] 2) After ball milling, suck the slurry into a beaker with a pipette and dry it in an oven at 60 °C for 12 h;
[0049] 3) Weigh the dried Ba2Co 0.5 Ru 1.5 O6 powder and 50 mg of carbon powder, and disperse them in a mixed solution containing 2.8 g of deionized water, 0.7 g of anion exchange, and 1.4 g of isopropanol;
[0050] 4) Spray the above solution onto a 3.5 * 3.5 cm 2 anion exchange membrane as the anode, and the spraying area is 2 * 2 cm 2 ;
[0051] 5) Prepare the commercial 20% Pt / C into a slurry following the above steps, and ultrasonically spray it on the same anion exchange membrane as the cathode;
[0052] 6) After spraying, dry it on a heating stage at 70 °C for 12 h to obtain the electrode of the anion exchange membrane electrolytic cell.
[0053] Example 3
[0054] This example provides a perovskite Ba2Co 1.5 Ru 0.5 O6 oxygen evolution membrane electrode. The pyrochlore Ba2Co 1.5 Ru0.5 The preparation method of the O6 oxygen evolution electrode includes the following steps:
[0055] 1) Weigh 50 mg of Ba2Co 1.5 Ru 0.5 O6 powder and place it in a ball milling jar. Add 5 g of a mixed solution (ethanol: acetone = 3:5), 3 g of zirconia ceramic balls to the powder, and ball mill the mixed slurry at a rotation speed of 300 r / min for 1 h;
[0056] 2) After ball milling, suck the slurry into a beaker with a pipette and place it in an oven to dry at 60 °C for 12 h;
[0057] 3) Weigh the dried Ba2Co 1.5 Ru 0.5 O6 powder and 50 mg of carbon powder, and disperse them in a mixed solution containing 2.8 g of deionized water, 0.7 g of anion exchange, and 1.4 g of isopropanol;
[0058] 4) Spray the above solution onto a 3.5 * 3.5 cm 2 anion exchange membrane as the anode using an ultrasonic sprayer, and the spraying area is 2 * 2 cm 2 ;
[0059] 5) Make a slurry of commercial 20% Pt / C in the same way as above steps and ultrasonically spray it onto the same anion exchange membrane as the cathode;
[0060] 6) After spraying, dry it on a heating table at 70 °C for 12 h to obtain the anion exchange membrane electrolytic cell electrode.
[0061] Example Results and Discussion
[0062] To prove its phase, the Ba2CoRuO6 powder obtained in Example 1 was subjected to lattice diffraction testing, and the results obtained are as Figure 1 shown. It can be seen from the figure that the Ba2CoRuO6 phase is a perovskite structure with a space group of Cmcm.
[0063] To prove its structure, the Ba2CoRuO6 powder obtained in Example 1 was subjected to electron microscopy scanning, and the scanning image obtained is as Figure 2 shown. It can be clearly seen from the figure that the structure of the Ba2CoRuO6 powder is granular.
[0064] To further prove the Ba2CoRuO6 structure, the Ba2CoRuO6 powder obtained in Example 1 was subjected to high-resolution transmission electron microscopy testing. It can be seen from Figure 3 that the lattice fringes are obvious, and the interplanar spacing of the (110) crystal plane is 0.286 nm.
[0065] The element distribution of the Ba2CoRuO6 powder in Example 1 was tested by transmission electron microscopy, and the measured element distribution is as Figure 4 shown. It can be seen from Figure 4 that the element distribution of the Ba2CoRuO6 powder provided in this example is uniform, proving its uniform element distribution.
[0066] Linear sweep voltammetry tests were performed on the Ba2CoRuO6 powder and commercial RuO2 using laboratory standard electrochemical test methods (1M KOH, Hg / HgO electrode as the reference electrode, the working electrode is a glassy carbon electrode, the counter electrode is a Pt mesh, and the LSV scan rate is 5 mV / s), as Figure 5 shown. The figure shows that when the current density of the Ba2CoRuO6 catalyst is 10 mA / cm 2 , the overpotential is only 225 mV, and the overpotential of commercial RuO2 is 340 mV. The Tafel slope calculated from the LSV curve is shown in Figure 6 . The figure shows that the Tafel slope of the Ba2CoRuO6 catalyst is 46.01 mV dec -1 , and the Tafel slope of commercial RuO2 is 64.36 mV dec -1 . It can be seen that the Pb2CoRuO7 catalyst has excellent catalytic performance.
[0067] Electrolyzer tests were performed on the oxygen evolution electrodes in Examples 1, 2, and 3 using linear sweep voltammetry, and the measured LSV curves are as Figure 7 shown. It can be seen from Figure 7 that when the current density of the oxygen evolution electrode in Example 1 is 100 mA / cm 2 , the overpotential of Ba2CoRuO6 is only 350 mV; the overpotential of Ba2Co 0.5 Ru 1.5 O6 in Example 2 is 430 mV, and the overpotential of Ba2Co 1.5 Ru 0.5 O6 in Example 3 is 460 mV. It can be seen that the Ba2CoRuO6 oxygen evolution electrode provided in this example has good catalytic performance.
[0068] The anion exchange membrane electrolyzer stability test was performed on the Ba2CoRuO6 oxygen evolution electrode using constant current testing, and the voltage change obtained is as Figure 8 shown. It can be seen from Figure 8 that the Pb2CoRuO7 oxygen evolution electrode provided in Example 1 of this embodiment has excellent electrolytic water stability.
[0069] In summary, in the embodiment of the present invention, cobalt-based materials are used for electrolyzing water, and cobalt-based perovskite Ba2Co 2-x M xO6 (M = Fe, Ni, Ru, Ir) and prepare an anion exchange membrane oxygen evolution electrode. The synergistic effect of transition metals and Co greatly improves its oxygen evolution activity.
[0070] Although the specific embodiments of the present invention have been described in conjunction with the accompanying drawings, they do not limit the protection scope of the present invention. Based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.
Claims
1. A cobalt-based perovskite catalyst, characterized in that, Its molecular formula is Ba2Co 2-x M x O6, where M = Fe, Ni, Ru, Ir and 0 < x < 2.
2. The cobalt-based perovskite catalyst according to claim 1, wherein x takes 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.
75.
3. The application of the cobalt-based perovskite catalyst described in claim 1 in the hydrogen production of an alkaline anion exchange membrane electrolyzer.
4. A method for hydrogen production in an alkaline anion exchange membrane electrolyzer using the catalyst according to claim 1, characterized in that, The specific steps are as follows: S1. First, mix and ball-mill the aforementioned catalyst, mixed solution I, and zirconia ceramic balls to obtain a ball-milled material; S2. Mix the ball-milled material with carbon powder and dissolve it in mixed solution II, add a dispersant, and perform roll milling to obtain a slurry; S3. Ultrasonically spray the slurry onto the anion exchange membrane to serve as an oxygen evolution anode, and prepare a slurry from commercial 20% Pt / C in the same manner as in step S1, and ultrasonically spray it onto the anion exchange membrane to serve as a hydrogen evolution cathode.
5. The method according to claim 4, characterized in that, In step S1, the composition of mixed solution I is ethanol and acetone, and the mass fraction accounts for 99% of the final slurry. The added mass fraction of acetone is 50% of that of ethanol.
6. The method according to claim 4, wherein In step S1, the diameter size of the zirconia ceramic balls is 0.5 - 1 cm, and the mass ratio to the slurry is 1:1.
5.
7. The method according to claim 4, wherein In step S1, the rotational speed of the ball mill is 200 - 300 rpm, and the ball-milling time is 1 - 2 h. The purpose of ball milling is to reduce the particle size of the material and provide a larger active area for the material.
8. The method according to claim 4, wherein In step S2, the particle size of the ball-milled material is weighed to be 20 - 60 nm, and the total mass fraction of the ball-milled material and carbon powder accounts for 2% of the final slurry, where the mass fraction of the ball-milled material in the two powders is not less than 40%.
9. The method according to claim 4, characterized in that, In step S2, the composition of mixed solution II is deionized water and an anion exchange solution, and the mass fraction accounts for 70% of the final slurry; the added mass fraction of deionized water is 80% of the two liquids; The dispersant includes but is not limited to isopropanol, butanol, acetone, polypropylene, fish oil, etc., and the mass fraction accounts for 28% of the final slurry; The roll milling time is 12 hours.
10. The method according to claim 4, wherein In step S3, an anion exchange membrane with a size of 3.5 * 3.5 cm is selected. -2 , and the spraying area on the membrane is 2 * 2 cm. -2 After spraying, it is dried on a heating table at 70 °C for 12 h.