A catalyst based on the synergistic effect of cobalt and nickel and its application

Abstract

The present invention relates to the field of materials, and particularly to a highly efficient catalyst Na2Co 2‑x Ni x TeO6 and its preparation method, which not only improve the performance of the catalyst, but also significantly enhance its stability and durability in practical applications, providing important theoretical and practical guidance for future energy conversion technologies.

Description

Technical Field

[0001] The present invention relates to the field of materials, and particularly to a high-efficiency catalyst for catalytic water decomposition and a preparation method thereof. Background Art

[0002] The pursuit of efficient and sustainable energy conversion technologies has driven in-depth research on electrocatalysts, especially on the oxygen evolution reaction (OER). OER is a key process in water electrolysis and metal-air batteries and is a fundamental reaction for generating clean hydrogen fuel from renewable energy. Transition metal-based catalysts have attracted much attention due to their high performance, multiple valence states, and abundant reserves.

[0003] Among these catalysts, cobalt-based catalysts have attracted extensive attention and research, including cobalt oxides, phosphides, nitrides, phosphates, sulfides, and selenides. In recent years, researchers have increasingly explored introducing nickel (Ni) into cobalt (Co) compounds to enhance their oxygen evolution reaction performance, and this strategy utilizes the synergistic effect and structural modification.

[0004] Research by Lanzhou University of Technology has shown that the excellent performance of Co 3 Ni 1 -N-C is attributed to its unique wrinkled carbon nanosphere structure and the synergistic effect between Co-Ni alloy nanoparticles and the nitrogen-doped carbon layer, providing multiple active sites and accelerating the reaction rate. The synthesis of wrinkled nitrogen-doped carbon nanospheres was carried out using a soft template method, adding cobalt and nickel salts to prepare bimetallic Co-Ni alloy nanoparticles. By incorporating melamine as a nitrogen source, the distribution and content of active sites were improved, and the surface area and active site density of the catalyst were increased. The oxygen evolution reaction (OER) performance was tested. Co 3 Ni 1 -N–C exhibited OER electrocatalytic performance with an overpotential of 0.360 V at a current density of 10 mA / cm 2 and a Tafel slope of 100 mV / dec, having a relatively high overpotential and Tafel slope. However, its synthesis process is relatively complex, including multi-step synthesis and specific experimental conditions, which limits the possibility of its large-scale preparation and industrial application. Moreover, the doping ratio of cobalt and nickel has not been further explored. Although it shows good stability in short-term tests, its stability under long-term and complex environments still needs to be further verified and studied. Especially under high potential conditions, the migration and aggregation of metal particles may affect the long-term performance of the catalyst. Although various characterization techniques have been used for performance analysis, there are still challenges in understanding the microstructure of active sites and the reaction mechanism, and more in-depth research and analysis are needed. Summary of the Invention

[0005] Problems to be Solved by the Invention

[0006] To solve the above problems existing in the prior art, the present invention provides an efficient oxygen evolution reaction electrocatalyst method, which utilizes the synergistic effect and structural modification of cobalt and nickel to improve the catalytic performance.

[0007] Solutions for solving problems

[0008] The present invention provides a catalyst, and the chemical general formula of the catalyst is Na 2 Co 2-x Ni x TeO 6 , where the value range of x is 0 ≤ x ≤ 1, and the value of x satisfies the charge balance of the chemical formula.

[0009] Preferably, the x is 0, 0.4, 0.8 or 1.0.

[0010] The present invention provides a preparation method of the above catalyst, including the following steps:

[0011] S1: Take the precursor materials Na 2 CO 3 , CoO, NiO and TeO 2 , and after grinding and mixing, obtain a mixture;

[0012] S2: Calcine the mixture obtained in step S1 to obtain a precursor;

[0013] S3: Sinter the precursor obtained in step S2 to obtain the catalyst.

[0014] Preferably, in step S1, the grinding is performed using an agate mortar.

[0015] Preferably, the grinding time is 20 - 100 min, preferably 20 - 60 min, and more preferably 40 min.

[0016] Preferably, the calcination in step S2 and the sintering in step S3 are carried out in a crucible.

[0017] Preferably, the crucible is one of a corundum crucible and a porcelain crucible, preferably a corundum crucible, and more preferably an alumina crucible.

[0018] Preferably, in step S2, the calcination temperature is 600 °C to 700 °C, the heating rate is 4 °C / min to 6 °C / min, and the calcination time is 10 hours to 20 hours.

[0019] Preferably, after the calcination in step S2, cooling is also required.

[0020] More preferably, the temperature after cooling is 20 °C to 30 °C, and the cooling rate is 4 °C / min to 6 °C / min.

[0021] Preferably, the calcination temperature is 650 °C, the heating rate is 5 °C / min, and the calcination time is 10 to 15 hours.

[0022] Preferably, the temperature after cooling is 25 °C, and the cooling rate is 5 °C / min.

[0023] Preferably, in step S3, the sintering temperature is 700 to 900 °C, the heating rate is 4 to 6 °C / min, and the sintering time is 20 to 30 hours.

[0024] Preferably, in step S3, before sintering, grinding is required.

[0025] Preferably, the grinding is performed using an agate mortar; the grinding time is 20 - 100 min, preferably 20 - 60 min, and more preferably 40 min.

[0026] Preferably, in step S3, after sintering, cooling is also required.

[0027] More preferably, the temperature after cooling is 20 °C to 30 °C, and the cooling rate is 4 °C / min to 6 °C / min.

[0028] Preferably, the sintering temperature is 810 °C, the heating rate is 5 °C / min, and the sintering time is 23 to 27 hours.

[0029] Preferably, the temperature after cooling is 25 °C, and the cooling rate is 5 °C / min.

[0030] The present invention provides an application of the above catalyst and the catalyst prepared by the above preparation method in the process of electrolytic water hydrogen production.

[0031] Effects of the Invention

[0032] The present invention provides a Na 2 Co 2-x Ni x TeO 6 catalyst, which not only improves the performance of the catalyst, but also significantly enhances its stability and durability in practical applications, providing important theoretical and practical guidance for future energy conversion technologies. Na 2 Co 2-x Ni x TeO 6As a catalyst for the oxygen evolution reaction (OER), it has good durability, high activity, and low cost. Compared with other noble metals such as Pt, Ru, and Ir, it can be widely used in industrial production, such as the production of clean energy hydrogen. It can replace the traditional fossil fuel power generation method, reduce carbon dioxide emissions, protect the environment, combine with renewable energy systems such as photovoltaics to achieve efficient water splitting, convert hydrogen into electrical energy through fuel cells, and realize energy storage and reuse.

[0033] The present invention provides a method for synthesizing a Na 2 Co 2-x Ni x TeO 6 catalyst. By optimizing the mixing ratio and sintering conditions of the precursor materials and using cobalt-nickel doping to enhance the catalytic performance, an efficient and stable OER electrocatalyst is finally achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 SEM images of the Na 2 Co 2–x Ni x TeO 6 (x = 0, 0.4, 0.8, 1.0) catalysts prepared in Examples 1-4.

[0035] Figure 2 XRD diffraction patterns of the Na 2 Co 2–x Ni x TeO 6 (x = 0, 0.4, 0.8, 1.0) catalysts prepared in Examples 1-4.

[0036] Figure 3 Electrocatalytic oxygen evolution reaction performance diagrams of the Na 2 Co 2–x Ni x TeO 6 (x = 0, 0.4, 0.8, 1.0) catalysts prepared in Examples 1-4. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] To make the technical solutions and beneficial effects of the present invention more obvious and understandable, the following will be described in detail by listing specific embodiments. Among them, the drawings are not necessarily drawn to scale, and local features can be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0038] On the one hand, the present invention provides a catalyst, and the chemical general formula of the catalyst is Na2 Co 2-x Ni x TeO 6 , where the value range of x is 0 ≤ x ≤ 1, and the value of x satisfies the charge balance of the chemical formula.

[0039] In certain embodiments, x is 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0.

[0040] In certain embodiments, x is 0, 0.4, 0.8, or 1.0.

[0041] On the one hand, the present invention provides a method for preparing the above catalyst, comprising the following steps:

[0042] S1: Take the precursor materials Na 2 CO 3 , CoO, NiO, and TeO 2 , grind and mix them to obtain a mixture;

[0043] S2: Calcinate the mixture obtained in step S1 to obtain a precursor;

[0044] S3: Sinter the precursor obtained in step S2 to obtain a catalyst.

[0045] In certain embodiments, in step S1, when x is 0, the molar ratio of Na 2 CO 3 , CoO, and TeO 2 is Na 2 CO 3 :CoO:TeO 2 = 1:2:1.

[0046] In certain embodiments, in step S1, when x is 0.4, the molar ratio of Na 2 CO 3 , CoO, NiO, and TeO 2 is Na 2 CO 3 :CoO:NiO:TeO 2 = 1:1.6:0.4:1.

[0047] In certain embodiments, in step S1, when x is 0.8, the molar ratio of Na 2 CO 3 , CoO, NiO, and TeO 2 is Na 2 CO 3 :CoO:NiO:TeO 2 = 1:1.2:0.8:1.

[0048] In some embodiments, in step S1, when x is 1, Na 2 CO 3 , CoO, NiO and TeO 2 The molar ratio of Na 2 CO 3 :CoO:NiO:TeO 2 = 1:1:1:1.

[0049] In some embodiments, in step S1, the grinding is performed using an agate mortar.

[0050] In some embodiments, the grinding time is 20 - 100 min.

[0051] In some embodiments, the grinding time is 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min.

[0052] In some embodiments, in step S2, the calcination is carried out in a crucible.

[0053] In some embodiments, the crucible is one of a corundum crucible and a porcelain crucible.

[0054] In some embodiments, the crucible is a corundum crucible.

[0055] In some embodiments, the crucible is an alumina crucible.

[0056] In some embodiments, in step S2, the calcination temperature is 600°C to 700°C, the heating rate is 4°C / min to 6°C / min, and the calcination time is 10 hours to 20 hours.

[0057] In some embodiments, in step S2, the calcination temperature is 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, the heating rate is 4°C / min, 5°C / min, 6°C / min, and the calcination time is 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours.

[0058] In some embodiments, in step S2, the calcination temperature is 650°C, the heating rate is 5°C / min, and the calcination time is 10 hours to 15 hours.

[0059] In some embodiments, after roasting in step S2, cooling is also required.

[0060] In some embodiments, the temperature after cooling is 20°C to 30°C, and the cooling rate is 4°C / min to 6°C / min.

[0061] In some embodiments, the temperature after cooling is 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, and the cooling rate is 4°C / min, 5°C / min, 6°C / min.

[0062] In some embodiments, in step S2, the temperature after cooling is 25°C, and the cooling rate is 5°C / min.

[0063] In some embodiments, the sintering in step S3 is carried out in a crucible.

[0064] In some embodiments, the crucible is one of a corundum crucible and a porcelain crucible.

[0065] In some embodiments, the crucible is a corundum crucible.

[0066] In some embodiments, the crucible is an alumina crucible.

[0067] In some embodiments, in step S3, the sintering temperature is 700 to 900°C, the heating rate is 4°C / min to 6°C / min, and the sintering time is 20 hours to 30 hours.

[0068] In some embodiments, in step S3, the sintering temperature is 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C, 790°C, 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, the heating rate is 4°C / min, 5°C / min, 6°C / min, and the sintering time is 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours.

[0069] In some embodiments, in step S3, the sintering temperature is 810°C, the heating rate is 5°C / min, and the sintering time is 23 hours to 27 hours.

[0070] In some embodiments, before sintering in step S3, grinding is required.

[0071] In certain embodiments, the grinding is performed using an agate mortar.

[0072] In certain embodiments, the grinding time is 20 - 100 min.

[0073] In certain embodiments, the grinding time is 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min.

[0074] In certain embodiments, in step S3, after sintering, cooling is also required.

[0075] In certain embodiments, the temperature after cooling is 20°C to 30°C, and the cooling rate is 4°C / min to 6°C / min.

[0076] In certain embodiments, the temperature after cooling is 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, and the cooling rate is 4°C / min, 5°C / min, 6°C / min.

[0077] In certain embodiments, the temperature after cooling is 25°C, and the cooling rate is 5°C / min.

[0078] On the one hand, the present invention provides an application of the above catalyst and the catalyst prepared by the above preparation method in the process of electrolytic water for hydrogen production.

[0079] The method of the present invention will be described below through specific examples. It should be understood that these examples are used to illustrate the basic principles, main features, and advantages of the present invention, and the present invention is not limited by the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0080] In the following examples, unless otherwise specified, all temperatures are in Celsius. Unless otherwise specified, various starting materials and reagents are commercially available or synthesized according to known methods. Commercially available raw materials and reagents are used directly without further purification. Unless otherwise specified, commercially available manufacturers include but are not limited to DANIINGPAI, ALADDIN, SCR, DAMAS - BETA, etc.

[0081] Example 1 Preparation of Na 2 Co 2 TeO 6 Polycrystalline sample

[0082] Take the precursor material Na2 CO 3 (DANIINGPAI, 99.8+%), CoO (ALADDIN, 99.9%), and TeO 2 (damas-beta, 99.99%) in a molar ratio of Na 2 CO 3 :CoO:TeO 2 = 1:2:1 were mixed and ground in an agate mortar for 40 minutes to ensure thorough mixing. The mixture was loaded into an alumina crucible and heated in an air environment starting from 25°C at a rate of 5°C / min to 650°C for 12 hours, then cooled to room temperature of 25°C at a rate of 5°C / min to obtain a precursor material. After cooling, the resulting powder was reground, loaded again into the alumina crucible, and heated in an air environment starting from 25°C at a rate of 5°C / min to 810°C for 24 hours, then cooled to room temperature of 25°C at a rate of 5°C / min to obtain Na 2 Co 2 TeO 6 polycrystalline sample.

[0083] Example 2 Preparation of Na 2 Co 1.6 Ni 0.4 TeO 6 polycrystalline sample

[0084] Take the precursor material Na 2 CO 3 (DANIINGPAI, 99.8+%), CoO (ALADDIN, 99.9%), NiO (SCR, 98.0+%), and TeO 2 (damas-beta, 99.99%) in a molar ratio of Na 2 CO 3 :CoO:NiO:TeO 2 = 1:1.6:0.4:1 were mixed and ground in an agate mortar for 40 minutes to ensure thorough mixing. The mixture was loaded into an alumina crucible and heated in an air environment starting from 25°C at a rate of 5°C / min to 650°C for 12 hours, then cooled to room temperature of 25°C at a rate of 5°C / min to obtain a precursor material. After cooling, the resulting powder was reground, loaded again into the alumina crucible, and heated in an air environment starting from 25°C at a rate of 5°C / min to 810°C for 24 hours, then cooled to room temperature of 25°C at a rate of 5°C / min to obtain Na 2 Co 1.6 Ni 0.4 TeO 6 polycrystalline sample.

[0085] Example 3 Preparation of Na 2 Co 1.2 Ni 0.8 TeO 6 polycrystalline sample

[0086] Take the precursor materials Na 2 CO 3 (DANIINGPAI, 99.8+%), CoO (ALADDIN, 99.9%), NiO (SCR, 98.0+%) and TeO 2 (damas-beta, 99.99%) in a molar ratio of Na 2 CO 3 :CoO:NiO:TeO 2 =1:1.2:0.8:1 and mix them, then grind them in an agate mortar for 40 minutes to ensure thorough mixing. Put the mixture into an alumina crucible, start from 25°C in an air environment, heat it at a rate of 5°C / min to 650°C and heat for 12 hours, then cool it to room temperature of 25°C at a rate of 5°C / min to obtain the precursor material. After cooling, re-grind the obtained powder, put it into the alumina crucible again, and start from 25°C in an air environment, heat it at a rate of 5°C / min to 810°C and sinter for 24 hours, then cool it to room temperature of 25°C at a rate of 5°C / min to obtain the Na 2 Co 1.2 Ni 0.8 TeO 6 polycrystalline sample.

[0087] Example 4 Preparation of Na 2 CoNiTeO 6 polycrystalline sample

[0088] Take the precursor materials Na 2 CO 3 (DANIINGPAI, 99.8+%), CoO (ALADDIN, 99.9%), NiO (SCR, 98.0+%) and TeO 2 (damas-beta, 99.99%) in a molar ratio of Na 2 CO 3 :CoO:NiO:TeO 2Mix in a ratio of 1:1:1:1 and grind with an agate mortar for 40 minutes to ensure thorough mixing. Load the mixture into an alumina crucible, start from 25 °C in an air environment, heat it at a rate of 5 °C / min to 650 °C for 12 hours, and then cool it to room temperature of 25 °C at a rate of 5 °C / min to obtain a precursor material. After cooling, re-grind the obtained powder, reload it into the alumina crucible, and start from 25 °C in an air environment, heat it at a rate of 5 °C / min to 810 °C for sintering for 24 hours, and then cool it to room temperature of 25 °C at a rate of 5 °C / min to obtain Na 2 CoNiTeO 6 polycrystalline sample.

[0089] Example 5 Na 2 Co 2–x Ni x TeO 6 (x = 0, 0.4, 0.8, 1.0) catalytic performance test

[0090] Disperse 5 mg of Na 2 Co 2–x Ni x TeO 6 (x = 0, 0.4, 0.8, 1.0) powder in a solution composed of 250 μL of deionized water, 250 μL of ethanol, and 25 μL of Nafion solution (0.5%), and ultrasonically treat for 30 minutes to ensure its uniformity. After preparation, take 2 μL of the catalyst ink drop on the surface of the glassy carbon electrode and dry it at room temperature for 2 hours. Adding the Nafion solution aims to improve the stability and dispersibility of the powder on the electrode surface. In a three-electrode reaction system, the reference electrode selected is a saturated calomel electrode, and the counter electrode is a carbon rod electrode. Among them, the rotation speed of the rotating disk electrode is set to 1600 rpm. First, use different scanning speeds of 5 mV / s, 10 mV / s, 20 mV / s to see the performance of linear sweep voltammetry (LSV) in 1.0 M KOH solution, and then perform OER cyclic tests on the obtained materials at a scanning rate of 5 mV / s, and the number of cycles is 100 times, 200 times, and 300 times respectively. The specific results of the OER test are as Figure 3 shown, the catalytic performance improves with the increase of nickel content. When x = 1.0, Na 2 CoNiTeO 6 exhibits the best activity, reaching a minimum onset potential of 1.53 V at a current density of 10 mA / cm 2 and only showing an overpotential of 0.300 V, comparable to commercial RuO 2 , see in detail Figure 3 (a). Further through Figure 3(b) The Tafel curves shown provide in-depth understanding of the catalytic performance. It is found that when the concentrations of cobalt and nickel are equal, the slope decreases from 108 mV / dec to a minimum of 58 mV / dec. In addition, to evaluate the stability of Na 2 Co 2–x Ni x TeO 6 in the oxygen evolution reaction (OER), cyclic voltammetry (CV) tests were carried out 100 - 300 times between 1.3 V and 1.8 V vs. RHE, as shown in Figure 3 (c)-(f). Generally speaking, Na 2 Co 2–x Ni x TeO 6 (x = 0, 0.4, 0.8, 1.0) shows strong stability as an OER catalyst, maintaining its performance with minimal degradation during 300 cycles. This stability is crucial for the practical applications of water splitting and other electrochemical processes, where the long-term durability of the catalyst is essential.

[0091] It should be understood that the above embodiments are all exemplary and do not cover all possible implementation manners included in the claims. Without departing from the scope of the present disclosure, various deformations and changes can also be made based on the above embodiments. Similarly, any combination of the technical features of the above embodiments can be made to form additional embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only represent several implementation manners of the present invention and do not limit the protection scope of the present invention patent.

Claims

1. Application of a catalyst in the process of producing hydrogen by electrolysis of water, characterized in that: The general chemical formula of the catalyst is Na2Co 2-X Ni x TeO6, the value range of x is 0≤x≤1, and the value of x satisfies the charge balance of the chemical formula.

2. The use according to claim 1, characterized in that: The x is 0, 0.4, 0.8 or 1.

0.

3. The use according to claim 1, characterized in that: The preparation method of the catalyst comprises the following steps: S1: taking precursor materials Na2CO3, CoO, NiO and TeO2, grinding and mixing them to obtain a mixture; S2: calcining the mixture obtained in step S1 to obtain a precursor; S3: Sinter the precursor obtained in step S2 to obtain a catalyst.

4. The use according to claim 3, characterized in that: In the step S1, the grinding is performed using an agate mortar.

5. The use according to claim 3, characterized in that: The grinding time is 20-100 min.

6. The use according to claim 5, characterized in that: The grinding time is 20-60 min.

7. The use according to claim 6, characterized in that: The grinding time is 40 min.

8. The use according to claim 3, characterized in that: The calcination in step S2 and the sintering in step S3 are performed in a crucible.

9. The use according to claim 8, characterized in that: The crucible is one of a corundum crucible and a porcelain crucible.

10. The use according to claim 9, characterized in that: The crucible is a corundum crucible.

11. The use according to claim 10, characterized in that: The crucible is an alumina crucible.

12. The use according to any one of claims 3 to 11, characterized in that: In the step S2, the calcination temperature is 600°C to 700°C, the heating rate is 4°C / min to 6°C / min, and the calcination time is 10 hours to 20 hours.

13. The use according to any one of claims 3 to 11, characterized in that: In the step S2, after calcination, cooling is required.

14. The use according to claim 13, characterized in that The temperature after cooling is 20°C to 30°C, and the cooling rate is 4°C / min to 6°C / min.

15. The use according to claim 12, characterized in that: The calcination temperature is 650° C., the heating rate is 5° C. / min, and the calcination time is 10 to 15 hours.

16. The use according to claim 14, characterized in that The temperature after cooling is 25°C, and the cooling rate is 5°C / min.

17. The use according to claim 3, characterized in that: In the step S3, the sintering temperature is 700-900°C, the heating rate is 4°C / min-6°C / min, and the sintering time is 20 hours-30 hours.

18. The use according to claim 3, characterized in that: In the step S3, grinding is required before sintering.

19. The use according to claim 18, characterized in that The grinding is performed using an agate mortar; the grinding time is 20-100 minutes.

20. The use according to claim 19, characterized in that The grinding time is 20-60 min.

21. The use according to claim 20, characterized in that The grinding time is 40 min.

22. The use according to claim 3, characterized in that: In the step S3, after sintering, cooling is required.

23. The use according to claim 22, characterized in that The temperature after cooling is 20°C to 30°C, and the cooling rate is 4°C / min to 6°C / min.

24. The use according to claim 17, characterized in that: The sintering temperature is 810° C., the heating rate is 5° C. / min, and the sintering time is 23 hours to 27 hours.

25. The use according to claim 23, characterized in that The temperature after cooling is 25°C, and the cooling rate is 5°C / min.

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