Metal organic framework derived bimetallic doped electrolyzed water catalyst and preparation method thereof
By doping lanthanide metals and transition metals in cobalt-based metal organic frame materials, an efficient and stable metal-organic frame-derived bimetallic doped electrolytic catalyst was developed, which solved the problems of slow anode oxygen evolution reaction rate and unstable catalyst in the prior art, and achieved excellent activity and stability in acid oxygen evolution reaction.
Patent Information
- Application Number
- CN202510076511.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-17
- Publication Date
- 2025-05-13
AI Technical Summary
In the existing proton exchange membrane electrolytic technology, the slow rate of the anode oxygen evolution reaction seriously limits the efficiency of the entire electrolytic water system, and the existing catalyst is unstable under the acid oxygen evolution reaction conditions, and the catalyst activity rapidly decays.
A metal-organic frame-derived bimetallic doped electrolytic catalyst is developed to form a catalyst with excellent specific surface area and porosity by doping lanthanide metals and transition metals in cobalt-based metal organic frame materials, thereby improving its activity and stability in acidic oxygen evolution reactions.
The activity and stability of the electrolytic water catalyst are significantly improved. The overpotential of the catalyst at 10mAcm-2 is only 350±20mV, and it can run stably for more than 12 hours, avoiding the problem of unstable carbon materials in acidic reactions.
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Figure CN119972098A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of water electrolysis catalysts, and in particular relates to a metal organic framework derived bimetallic doped water electrolysis catalyst and a preparation method thereof. Background Art
[0002] Global industrial development and population growth have led to a rapid increase in demand for energy. The depletion of traditional fossil fuels and the greenhouse effect caused by carbon dioxide emissions have become serious problems. Hydrogen energy, as a new type of efficient and clean energy, is a bridge between fossil energy and renewable energy. Proton exchange membrane water electrolysis technology is a clean and efficient process of energy conversion. Its commercialization is conducive to promoting the transformation of energy structure and the realization of dual carbon goals. At present, a key problem encountered in the development of proton exchange membrane water electrolysis is the slow rate of oxygen evolution reaction at the anode, which greatly limits the efficiency of the entire water electrolysis system. Therefore, it is of great significance to develop a low-cost and efficient oxygen evolution reaction catalyst to promote the commercialization of proton exchange membrane water electrolysis technology.
[0003] CN 116479457 A discloses a method for preparing a carbon-coated cobalt tetraoxide nanomaterial, wherein a precursor solution is applied to the carbon paper after pre-treatment of the hydrophilic carbon paper, and then the carbon-coated cobalt tetraoxide catalyst is obtained by calcination, and the catalyst has good electrocatalytic performance. The method is simple in process, but the carbon material is unstable under acidic oxygen evolution reaction conditions, resulting in rapid attenuation of the catalyst activity.
[0004] Therefore, a new water electrolysis catalyst with high catalytic activity and stability that can be used for acidic oxygen evolution reaction remains to be developed. Summary of the invention
[0005] The purpose of the present invention is to provide a metal organic framework derived bimetallic doped water electrolysis catalyst and a preparation method thereof in order to develop a new water electrolysis catalyst that can be used for acidic oxygen evolution reaction.
[0006] The purpose of the present invention can be achieved by the following technical solutions:
[0007] The present invention first provides a metal organic framework derived bimetallic doped water electrolysis catalyst, wherein the water electrolysis catalyst uses a cobalt-based metal organic framework material as a precursor, and the cobalt-based metal organic framework material is doped with a lanthanide metal and a transition metal;
[0008] The cobalt-based metal organic framework material is formed by self-assembly after mixing a cobalt source and an organic ligand;
[0009] The water electrolysis catalyst is used for catalyzing the acidic oxygen evolution reaction in the proton exchange membrane water electrolysis.
[0010] Furthermore, the ratio of the molar amount of the cobalt source to the total molar amount of the two doping metals is 49:1 to 17:3.
[0011] Furthermore, the ratio of the total molar amount of the cobalt source, the lanthanide metal and the transition metal to the molar amount of the organic ligand is 1:1 to 4:1.
[0012] Furthermore, the cobalt source includes one of acetate or chloride.
[0013] Furthermore, the lanthanide metal is a nitrate, which includes any one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
[0014] Furthermore, the transition metal includes any one of nitrate, acetate or sulfate.
[0015] Furthermore, the transition metal is selected from any one of scandium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, bismuth, tin, lead, barium, calcium and molybdenum.
[0016] Furthermore, the organic ligand includes one or more of terephthalic acid, 2-methylimidazole, 2,5-dihydroxyterephthalic acid, terephthalic acid, and 2-ethylimidazole.
[0017] The present invention also provides a method for preparing a metal organic framework-derived bimetallic doped water electrolysis catalyst, which specifically comprises the following steps:
[0018] S1: dissolving a cobalt source, a lanthanide metal source and a transition metal source in an organic solvent to obtain a metal source solution, and dissolving an organic ligand in an organic solvent to obtain an organic ligand solution;
[0019] S2: transferring the organic ligand solution to the metal source solution for reaction, collecting the product, and obtaining a bimetallic doped cobalt-based metal organic framework material;
[0020] S3: heat-treating the bimetallic-doped cobalt-based metal-organic framework material, and grinding it to obtain the metal-organic framework-derived bimetallic-doped water electrolysis catalyst.
[0021] Furthermore, in step S2, both solutions need to be stirred and dispersed evenly at room temperature.
[0022] Furthermore, in step S2, the reaction is carried out at 20-30° C. and the reaction time is 1-12 h.
[0023] Furthermore, in step S2, the product is collected by centrifugation and dried after centrifugation.
[0024] Furthermore, in step S3, the temperature of the heat treatment is 300-500° C., and the time of the heat treatment is 1-6 hours.
[0025] The present invention provides a novel electrochemical catalyst that can be used for acidic oxygen evolution reaction, which has excellent activity and stability. Among them, metal organic framework materials have the advantages of large specific surface area, rich pore structure, diverse components, clear metal center, etc., so they can be used as precursors to increase the specific surface area and porosity of the catalyst and dope other metals. Doping is an effective strategy to change the catalyst components and electronic structure, and the synergistic effect caused by bimetallic doping can further optimize the properties of the catalyst, improve its electrochemical active area, charge transfer ability and structural stability, thereby improving the activity and stability of the catalyst during the oxygen evolution reaction.
[0026] Compared with the prior art, the present invention has the following beneficial effects:
[0027] (1) The metal organic framework-derived bimetallic doped water electrolysis catalyst of the present invention uses a cobalt-based metal organic framework material as a precursor, which has a high specific surface area and porosity, and significantly improves the activity and stability of the water electrolysis catalyst under the synergistic effect of bimetallic doping of lanthanide metals and transition metals.
[0028] (2) The present invention significantly improves the activity and stability of the catalyst through the synergistic effect of two metal dopings. The doping of lanthanide metals can increase the content of oxygen vacancies in the catalyst and generate strain to improve structural stability, while the doping of transition metals can improve its charge transfer ability and thus improve activity.
[0029] (3) The electrolytic water catalyst prepared by the method of the present invention has a -2 The overpotential at the -2 It can run stably for more than 12 hours and is a non-precious metal catalyst for proton exchange membrane water electrolysis with great application prospects.
[0030] (4) The catalyst finally prepared by the method of the present invention is a metal oxide and does not contain carbon, thus avoiding the problem of carbon being unstable in the acidic oxygen evolution reaction, and making the catalyst have excellent stability.
[0031] (5) The present invention obtains the catalyst precursor, i.e., the metal organic framework material, by room temperature reaction, and then obtains the catalyst by low temperature annealing. The entire preparation process is simple, the catalyst composition and structure can be flexibly controlled, it has good repeatability, and it is easy to prepare in large quantities, which is of great significance to the development of non-precious metal water electrolysis catalysts. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 The figure is a flow chart of the preparation of the catalyst obtained in the embodiment of the present invention.
[0033] Figure 2 This is the XRD diagram and XPS full spectrum of the water electrolysis catalyst of Example 1 of the present invention.
[0034] Figure 3 This is the BET test result of the catalyst obtained in Example 1 of the present invention.
[0035] Figure 4 The OER linear voltammetric scan curves and cyclic voltammetric curves of the catalysts obtained in Example 1 and Comparative Examples 1-3 of the present invention in 0.1M HClO4 electrolyte and the OER linear voltammetric scan curves of Examples 2-7 are shown.
[0036] Figure 5 The cyclic voltammetry curves of the catalysts obtained in Example 1 of the present invention and Comparative Examples 1-3 in the non-ferrous region in 0.1M HClO4 electrolyte and the calculated double-layer capacitance values are shown.
[0037] Figure 6 The catalyst obtained in Examples 1-4 of the present invention was 10 mA cm in 0.1 M HClO4 electrolyte. -2 Constant current density test curve at . DETAILED DESCRIPTION
[0038] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.
[0039] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.
[0040] Embodiment 1:
[0041] This embodiment provides a metal organic framework derived bimetallic doped water electrolysis catalyst, the principle schematic diagram of the preparation process is as follows Figure 1 As shown, the specific preparation method is as follows:
[0042] (1) In a 100-mL beaker, 1 mmol of 2,5-dihydroxyterephthalic acid and 50 mL of methanol were added. In a 250-mL beaker, 3.2 mmol of cobalt acetate tetrahydrate, 0.18 mmol of neodymium nitrate hexahydrate, 0.18 mmol of bismuth nitrate pentahydrate and 100 mL of methanol were added. The mixture was stirred at 25° C. for 15 min to obtain a uniform solution.
[0043] (2) The organic ligand solution was transferred to a 250 ml beaker containing the metal source solution, reacted at room temperature for 6 h, centrifuged with methanol (8000 rpm, 3 min) three times, and then the solid was placed at 60 °C for 8 h in vacuum drying.
[0044] (3) The cobalt-based metal organic framework material doped with neodymium and bismuth is placed in a tube furnace for annealing heat treatment. The temperature is raised to 400°C at a rate of 3°C / min in an air atmosphere. After being kept at this temperature for 2 hours, the material is naturally cooled to room temperature to obtain a cobalt-based oxide water electrolysis catalyst doped with a bimetallic compound.
[0045] Embodiment 2:
[0046] This embodiment provides a metal organic framework derived bimetallic doped water electrolysis catalyst, which is different from embodiment 1 in that step (1) of this embodiment is:
[0047] 1 mmol 2,5-dihydroxyterephthalic acid and 50 ml methanol were added to a 100 ml beaker, 3.2 mmol cobalt acetate tetrahydrate, 0.18 mmol erbium nitrate hexahydrate, 0.18 mmol bismuth nitrate pentahydrate and 100 ml methanol were added to a 250 ml beaker, and the mixture was stirred at 25° C. for 15 min to obtain a uniform solution.
[0048] Embodiment 3:
[0049] This embodiment provides a metal organic framework derived bimetallic doped water electrolysis catalyst, which is different from embodiment 1 in that step (1) of this embodiment is:
[0050] 1 mmol 2,5-dihydroxyterephthalic acid and 50 ml methanol were added to a 100 ml beaker, 3.2 mmol cobalt acetate tetrahydrate, 0.18 mmol cerium nitrate hexahydrate, 0.18 mmol bismuth nitrate pentahydrate and 100 ml methanol were added to a 250 ml beaker, and stirred at 25° C. for 15 min to obtain a uniform solution.
[0051] Embodiment 4:
[0052] This embodiment provides a metal organic framework derived bimetallic doped water electrolysis catalyst, which is different from embodiment 1 in that step (1) of this embodiment is:
[0053] 1 mmol 2,5-dihydroxyterephthalic acid and 50 ml methanol were added to a 100 ml beaker, 3.2 mmol cobalt acetate tetrahydrate, 0.18 mmol neodymium nitrate hexahydrate, 0.18 mmol chromium nitrate nonahydrate and 100 ml methanol were added to a 250 ml beaker, and stirred at 25° C. for 15 min to obtain a uniform solution.
[0054] Embodiment 5:
[0055] This embodiment provides a metal organic framework derived bimetallic doped water electrolysis catalyst, which is different from embodiment 1 in that step (1) of this embodiment is:
[0056] 1 mmol 2,5-dihydroxyterephthalic acid and 50 ml methanol were added to a 100 ml beaker, 3.2 mmol cobalt acetate tetrahydrate, 0.18 mmol cerium nitrate hexahydrate, 0.18 mmol chromium nitrate nonahydrate and 100 ml methanol were added to a 250 ml beaker, and stirred at 25° C. for 15 min to obtain a uniform solution.
[0057] Embodiment 6:
[0058] This embodiment provides a metal organic framework derived bimetallic doped water electrolysis catalyst, which is different from embodiment 1 in that step (1) of this embodiment is:
[0059] 1 mmol 2,5-dihydroxyterephthalic acid and 50 ml methanol were added to a 100 ml beaker, 3.2 mmol cobalt acetate tetrahydrate, 0.18 mmol neodymium nitrate hexahydrate, 0.18 mmol ferric nitrate nonahydrate and 100 ml methanol were added to a 250 ml beaker, and stirred at 25° C. for 15 min to obtain a uniform solution.
[0060] Embodiment 7:
[0061] This embodiment provides a metal organic framework derived bimetallic doped water electrolysis catalyst, which is different from embodiment 1 in that step (1) of this embodiment is:
[0062] 1 mmol 2,5-dihydroxyterephthalic acid and 50 ml methanol were added to a 100 ml beaker, 3.2 mmol cobalt acetate tetrahydrate, 0.18 mmol erbium nitrate hexahydrate, 0.18 mmol ferric nitrate nonahydrate and 100 ml methanol were added to a 250 ml beaker, and stirred at 25° C. for 15 min to obtain a uniform solution.
[0063] Comparative Example 1:
[0064] The basic preparation steps are the same as those in Example 1, except that neodymium nitrate hexahydrate and bismuth nitrate pentahydrate are not added in step 1 of this comparative example.
[0065] Comparative Example 2:
[0066] The basic preparation steps are the same as those in Example 1, except that bismuth nitrate pentahydrate is not added in step 1 of this comparative example.
[0067] Comparative Example 3:
[0068] The basic preparation steps are the same as those in Example 1, except that neodymium nitrate hexahydrate is not added in step 1 of this comparative example.
[0069] The present invention performs the following tests on Examples 1-3 and Comparative Examples:
[0070] The catalysts obtained in Example 1 and Comparative Example 1 were characterized by XRD and XPS. Figure 2 As shown, it can be seen that the corresponding crystal phase of XRD has not changed and the peak of the doping element appears in XPS, indicating that the two elements are successfully incorporated into the catalyst.
[0071] The catalyst obtained in Example 1 was subjected to BET characterization, and the results were as follows: Figure 3 As shown in the figure, it can be seen that the bimetallic doped cobalt-based oxide water electrolysis catalyst has a large specific surface area and porosity, which are 75.8 m 2 g -1 and 0.187cm 3 g -1 , which is beneficial to the improvement of catalyst performance.
[0072] The electrochemical performance of the catalysts obtained in all the examples and comparative examples was characterized respectively. The test method was as follows: 5 mg of catalyst, 30 μl of 5 wt% Nafion ionomer solution, 170 μl of water and 600 μl of isopropanol were used to prepare a catalyst slurry. After ultrasonic treatment for 2 hours, 20 μl was dripped onto the surface of the gold disk electrode. After natural drying, a uniform film was formed. The activity of the catalyst was then evaluated under a three-electrode system, in which the gold disk electrode loaded with the catalyst film was the working electrode, the counter electrode and the reference electrode were gold wire and Hg / Hg2SO4 electrodes, respectively, the electrolyte was 0.1 M HClO4, the rotation speed of the rotating disk electrode was 1600 rpm, and the CHI760E electrochemical workstation was used to measure the voltage in the range of 1.0 to 2.0 V vs. RHE at 10 mV s -1 Linear sweep voltammetry was performed to evaluate the performance of the catalyst.
[0073] The OER linear voltammetric scanning curves of the ten catalysts and the cyclic voltammetric curves of Example 1 and Comparative Examples 1, 2, and 3 are shown in FIG. Figure 4 As shown. Figure 4 A and Figure 4 B shows that the overpotential of the undoped Co3O4 catalyst is 445 mV, and the overpotential of the Co3O4 catalyst after Nd and Bi are doped separately is reduced to 397 mV and 343 mV, respectively. After the two metals are co-doped, the overpotential is further reduced to 335 mV, indicating that the synergistic effect of the two metal doping further improves the activity of the catalyst. Figure 4C shows that the catalysts doped with ErBi, CeBi, NdCr, CeCr, NdFe, and ErFe can significantly improve the performance of the catalyst, indicating the universality of the method. At the same time, the performance is slightly worse than that of Example 1, indicating that the catalyst co-doped with Nd and Bi has better performance. In summary, the metal organic framework-derived bimetallic doping prepared by the present invention effectively reduces the OER overpotential and improves the OER performance of the catalyst.
[0074] The catalysts obtained in Example 1 and Comparative Examples 1, 2, and 3 were subjected to cyclic voltammetry tests in the non-Faraday range. The test results of the four catalysts were compared. Figure 5 As shown. Figure 5 As shown in Figure AD, the undoped Co3O4 catalyst and the Nd, Bi single-doped catalysts and the co-doped catalysts have a voltage range of 1.1-1.2 V vs. RHE with a speed of 2-12 mV s -1 Cyclic voltammetry was performed at a scan rate of 1.5 to measure the double layer capacitance of each catalyst. Figure 5 As shown in Figure 5, the double layer capacitance of the undoped Co3O4 catalyst is only 3.49 mF cm -2 The double layer capacitance of the catalyst doped with Nd and Bi is 8.83 mF cm -2 and 9.74mF cm -2 The double-layer capacitance of the catalyst doped with Nd and Bi was further increased to 11.77 mF cm -2 It can be seen that the metal organic framework derived bimetallic doping prepared according to the preparation method of the present invention effectively increases the double electric layer capacitance value of the catalyst, indicating that the catalyst exposes more reactive active sites.
[0075] The stability of the catalysts prepared in Examples 1-4 was characterized at 10 mA cm -2 The constant current density test was carried out at Figure 6 As shown. It can be seen that the metal organic framework derived bimetallic doped water electrolysis catalysts prepared by the present invention can be used at 10 mA cm -2 The catalyst ran stably for more than 12 h, indicating that the prepared metal oxide catalyst had good stability.
[0076] In summary, the present invention provides a new electrochemical catalyst that can be used for acidic oxygen evolution reaction, which has excellent activity and stability. At the same time, the preparation method is simple and efficient, the prepared catalyst has a stable structure, and is easy to mass produce, which is conducive to the large-scale application of proton exchange membrane water electrolysis technology, especially non-precious metal oxygen evolution catalysts.
[0077] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.
Claims
1. A metal organic framework derived bimetallic doped water electrolysis catalyst, characterized in that: The water electrolysis catalyst uses a cobalt-based metal organic framework material as a precursor, and the cobalt-based metal organic framework material is doped with a lanthanide metal and a transition metal; The cobalt-based metal organic framework material is formed by self-assembly after mixing a cobalt source and an organic ligand; The water electrolysis catalyst is used for catalyzing the acidic oxygen evolution reaction in the proton exchange membrane water electrolysis.
2. A metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 1, characterized in that: The ratio of the molar amount of the cobalt source to the total molar amount of the two doping metals is 49:1 to 17:
3.
3. The metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 1, characterized in that: The ratio of the total molar amount of the cobalt source, the lanthanide metal and the transition metal to the molar amount of the organic ligand is 1:1 to 4:
1.
4. The metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 1, characterized in that: The cobalt source includes one of an acetate salt or a chloride salt.
5. The metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 1, characterized in that: The lanthanide metal is a nitrate, which includes any one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
6. The metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 1, characterized in that: The transition metal includes any one of nitrate, acetate or sulfate; The transition metal is selected from any one of scandium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, bismuth, tin, lead, barium, calcium and molybdenum.
7. The metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 1, characterized in that: The organic ligand includes one or more of terephthalic acid, 2-methylimidazole, 2,5-dihydroxyterephthalic acid, terephthalic acid, and 2-ethylimidazole.
8. A method for preparing the metal organic framework derived bimetallic doped water electrolysis catalyst according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: dissolving a cobalt source, a lanthanide metal source and a transition metal source in an organic solvent to obtain a metal source solution, and dissolving an organic ligand in an organic solvent to obtain an organic ligand solution; S2: transferring the organic ligand solution to the metal source solution for reaction, collecting the product, and obtaining a bimetallic doped cobalt-based metal organic framework material; S3: heat-treating the bimetallic-doped cobalt-based metal-organic framework material, and grinding it to obtain the metal-organic framework-derived bimetallic-doped water electrolysis catalyst.
9. The method for preparing a metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 8, characterized in that: In step S2, the reaction is carried out at 20-30° C. for 1-12 h; The product was collected by centrifugation and dried after centrifugation.
10. The method for preparing a metal organic framework derived bimetallic doped water electrolysis catalyst according to claim 8, characterized in that: In step S3, the temperature of the heat treatment is 300-500° C., and the time of the heat treatment is 1-6 hours.