A ferrocene-doped MOF-derived metal carbide electrocatalyst and its preparation method and application

Abstract

The invention discloses a kind of ferrocenyl-doped MOF-derived metal carbide electrocatalyst and its preparation method and application, preparation method includes:ZIF 8 is dissolved in anhydrous methanol to obtain solution A;Ferrocenyl monocarboxylic acid is dissolved in DMF to obtain solution B;Solution A and solution B are mixed uniformly to obtain reaction solution, and reaction solution is subjected to hydrothermal reaction;The product obtained after the reaction is centrifuged, washed, dried, calcined and carbonized to obtain the ferrocenyl-doped MOF-derived metal carbide electrocatalyst.The catalyst of the present invention has the advantages of being porous, having many active sites, further improves the catalytic performance of electrocatalyst, can be applied to disposable zinc-air battery as oxygen reduction catalyst, and has excellent electrochemical performance under alkaline conditions (0.1M KOH).

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a ferrocene-doped MOF-derived metal carbide electrocatalyst, a preparation method thereof, and applications thereof. Background Art

[0002] With the advancement of science and technology, energy consumption is increasing. To address this challenge, people are constantly innovating technologies, developing new energy sources, and searching for more sustainable and renewable clean energy. Electrochemical technology, due to its excellent performance as a medium for energy conversion and storage, is attracting increasing attention. Currently, the design and development of low-cost, sustainable, green electrochemical energy storage devices has become a hot topic of research.

[0003] Metal-organic frameworks (MOFs) and MOF-derived materials have attracted widespread attention as alternatives to noble metal-based electrocatalysts due to their interesting structural properties, especially the efficient and stable oxygen reduction reaction (ORR). Zinc-air batteries (ZABs) mainly involve the oxygen reduction reaction, and its slow kinetics greatly limits the practical application of Zn-air batteries. In order to improve the speed and efficiency of the reaction, high-performance electrocatalytic materials are usually required to increase its half-wave potential (E 1 / 2 ), but the current efficient catalysts are still precious metals. Therefore, finding efficient and stable low-cost catalysts to solve the defects of zinc-air batteries is the future development trend.

[0004] The Chinese patent application document with publication number CN110148764A discloses a bifunctional catalyst for catalyzing ORR and OER, and its preparation and application. The atomically dispersed Fe-Co bimetallic sites (FeCo-NC) are obtained from Fe and Co co-doped zeolitic imidazolate framework (ZIF-8s). However, the atomically dispersed FeCo-NC catalyst has a poor performance in ORR (E 1 / 2 =0.877V), the performance is poor. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a new electrocatalyst containing ferrocenyl and having good catalytic performance and a preparation method thereof. The prepared catalyst can effectively improve the catalytic performance of redox reactions.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] A method for preparing a ferrocene-doped MOF-derived metal carbide electrocatalyst comprises the following steps:

[0008] S1. Dissolve ZIF-8 in anhydrous methanol to obtain solution A; dissolve ferrocene monocarboxylic acid in DMF to obtain solution B;

[0009] S2. Mixing solution A and solution B uniformly to obtain a reaction solution, and subjecting the reaction solution to a hydrothermal reaction;

[0010] S3. Centrifuging, washing, drying, calcining and carbonizing the product obtained after the reaction in S2 to obtain the ferrocene-doped MOF-derived metal carbide electrocatalyst.

[0011] Preferably, in S1, the mass volume ratio of the ZIF-8 and anhydrous methanol is 20 mg:2 mL.

[0012] Preferably, in S1, the mass volume ratio of ferrocene monocarboxylic acid and DMF is 2-10 mg:2 mL.

[0013] Preferably, in S2, the mass ratio of ZIF-8 to ferrocene monocarboxylic acid in the reaction solution is 20:2-10.

[0014] Preferably, in S2, the temperature of the hydrothermal reaction is 100°C and the time is 12-24 hours.

[0015] Preferably, in S3, the centrifugal conditions are: rotation speed 6000-10000 r / min, time 3-5 min; the drying conditions are: temperature 45-55° C., time 4-12 h.

[0016] Preferably, in S3, the calcination process includes: loading the dried material into a porcelain boat, placing it in a tube furnace and performing a primary heating and calcination under the protection of inert gas; acid leaching in a 0.3-0.6M H2SO4 solution for 20-30 hours, then loading it into a porcelain boat, and placing it in a tube furnace for a secondary heating and calcination under the same conditions as the primary heating and calcination.

[0017] Preferably, the temperature of the primary heating calcination and the secondary heating calcination is 900-950° C., the time is 1.5-2.5 h, and the heating rate is 3-5° C. / min.

[0018] The present invention also provides a ferrocenyl-doped MOF-derived metal carbide electrocatalyst, which is prepared by using the preparation method of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst.

[0019] The present invention also proposes an application of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst as an oxygen reduction catalyst in a zinc-air battery.

[0020] The advantages of the present invention are:

[0021] (1) The present invention uses ZIF-8 as a precursor and iron salt as a metal salt, encapsulates the ZIF-8 precursor in ferrocene monocarboxylic acid, and obtains a dodecahedral porous composite material after pyrolysis, which has good overall morphology and excellent thermal stability;

[0022] (2) The composite material prepared by the present invention can effectively generate a multi-porous structure during the instantaneous heat release during pyrolysis, and the overall morphology is well maintained before and after pyrolysis. It can be used as an oxygen reduction catalyst in disposable zinc-air batteries and has excellent electrochemical performance under alkaline conditions (0.1M KOH);

[0023] (3) The preparation process adopted by the present invention is simple, easy to reproduce, high in yield, and convenient for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a process flow chart of Example 1 of the present invention;

[0025] Figure 2 SEM images of the ZIF-8 precursor, ZnFc-MOF-M, and Fe3C-FeN / CM in Example 2 of the present invention; (a): ZIF-8 precursor, (b): ZnFc-MOF-M, (c): Fe3C-FeN / CM;

[0026] Figure 3 TEM images (a-b), lattice analysis images (c), and lattice images (d) of Fe3C-FeN / CM in Example 2 of the present invention;

[0027] Figure 4 Polarization curve (a) of the oxygen reduction reaction of the material Fe3C-FeN / CM prepared in Example 2 of the present invention in an O2-saturated 0.1 M KOH aqueous solution at 1600 rpm, the corresponding Tafel slope (b), methanol tolerance curve (c), stability test of the oxygen reduction reaction (d), and LSV before and after the oxygen reduction reaction stability test (e);

[0028] Figure 5 At 10mA / cm 2 Under the conditions, the polarization curve and power density curve (a), specific capacity curve (b), discharge curve (c), and discharge curve (d) of the zinc-air battery using the Fe3C-FeN / CM catalyst prepared in Example 2 at different current densities;

[0029] Figure 6 LSV curves of the catalysts prepared in Examples 1-3 of the present invention and the materials prepared in Comparative Examples 1-2;

[0030] Figure 7 This is the SEM image of the material prepared in Comparative Example 4 of the present invention. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0033] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0034] In the examples of the present invention, zinc nitrate hexahydrate was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; potassium hydroxide, anhydrous methanol, and Nafion solution were purchased from Sinopharm Chemical Reagent Co., Ltd.; and N,N-dimethylformamide (DMF) was purchased from Jiangsu Qiangsheng Functional Chemical Co., Ltd.; all of the above raw materials were of analytical grade.

[0035] Among the test devices used in the present invention, the scanning electron microscope (SEM, FlexSEM1000) was purchased from Hitachi High-Tech Corporation; the transmission electron microscope (TEM, JEM2100F) was purchased from JEOL Corporation of Japan; and the electrochemical workstation was purchased from Shanghai Chenhua Instrument Co., Ltd.

[0036] Example 1

[0037] Figure 1 The process flow chart of the preparation method of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst proposed in the present invention is shown in FIG. Figure 1 , the preparation method comprises the following steps:

[0038] S1: Weigh 6.16g of 2-methylimidazole and dissolve it in 150ml of methanol, record it as liquid A, weigh 5.95g of Zn(NO3)2·6H2O and dissolve it in 150ml of methanol, record it as liquid B, add the completely dissolved liquid A to liquid B, stir for 30 minutes, let it stand for 24 hours, centrifuge, wash the precipitate three times with anhydrous methanol, and dry it in an oven at 50℃. The obtained white powder is recorded as ZIF-8 precursor; weigh 20mg of ZIF-8 precursor and place it in a beaker, dissolve it in 2mL of anhydrous methanol solution to form a precursor solution; weigh 2mg of ferrocene monocarboxylic acid and place it in a beaker, dissolve it in 2mL of DMF solution to obtain a uniform clear solution;

[0039] S2: Add the clarified solution in S1 to the precursor solution in S1 at room temperature, and stir ultrasonically for 30 min to mix the materials evenly to obtain a reaction solution;

[0040] S3: The reaction solution in S2 was placed in a high-pressure reactor for hydrothermal reaction at 100°C for 12 h;

[0041] S4: The suspension after hydrothermal treatment was centrifuged, washed, and dried. The centrifugation conditions were: speed 8000 r / min, time 3 min, and the drying conditions were: temperature 50°C, time 12 h. 20 mg of the dried material ZnFc-MOF-L was placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a heating rate of 5°C / min. The mixture was heated under flowing nitrogen for 2 h. The mixture was acid-leached in 0.5 M H2SO4 solution for 24 h, then placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a heating rate of 5°C / min. The mixture was heated under flowing nitrogen for 2 h to obtain the ferrocenium-doped MOF-derived metal carbide electrocatalyst, which is a dodecahedral composite material and is recorded as Fe3C-FeN / CL.

[0042] Example 2

[0043] The preparation method of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst proposed in the present invention comprises the following steps:

[0044] S1: Weigh 20 mg of the ZIF-8 precursor in Example 1, place it in a beaker, and dissolve it in 2 mL of anhydrous methanol solution to form a precursor solution; weigh 5 mg of ferrocene monocarboxylic acid, place it in a beaker, and dissolve it in 2 mL of DMF solution to obtain a uniform clear solution;

[0045] S2: Add the clarified solution in S1 to the precursor solution in S1 at room temperature, and stir ultrasonically for 30 min to mix the materials evenly to obtain a reaction solution;

[0046] S3: The reaction solution in S2 was placed in a high-pressure reactor for hydrothermal reaction at 100°C for 12 h;

[0047] S4: The suspension after hydrothermal treatment was centrifuged, washed, and dried. The centrifugation conditions were: speed 8000 r / min, time 3 min, and drying conditions were: temperature 50°C, time 12 h. 20 mg of the dried material ZnFc-MOF-M was placed in a porcelain boat, placed in a tube furnace, heated to 920°C at a heating rate of 5°C / min, and heated under flowing nitrogen for 2 h. After acid leaching in 0.5 M H2SO4 solution for 24 h, the suspension was placed in a porcelain boat again, placed in a tube furnace, heated to 920°C at a heating rate of 5°C / min, and heated under flowing nitrogen for 2 h to obtain the ferrocenium-doped MOF-derived metal carbide electrocatalyst, which is a dodecahedral composite material, denoted as Fe3C-FeN / CM.

[0048] Example 3

[0049] The preparation method of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst proposed in the present invention comprises the following steps:

[0050] S1: Weigh 20 mg of the ZIF-8 precursor in Example 1, place it in a beaker, and dissolve it in 2 mL of anhydrous methanol solution to form a precursor solution; weigh 10 mg of ferrocene monocarboxylic acid, place it in a beaker, and dissolve it in 2 mL of DMF solution to obtain a uniform clear solution;

[0051] S2: Add the clarified solution in S1 to the precursor solution in S1 at room temperature, and stir ultrasonically for 30 min to mix the materials evenly to obtain a reaction solution;

[0052] S3: The reaction solution in S2 was placed in a high-pressure reactor for hydrothermal reaction at 100°C for 12 h;

[0053] S4: The suspension after hydrothermal treatment was centrifuged, washed, and dried. The centrifugation conditions were: speed 8000 r / min, time 3 min, and drying conditions were: temperature 50°C, time 12 h. 20 mg of the dried material ZnFc-MOF-H was placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a heating rate of 5°C / min. The material was heated under flowing nitrogen for 2 h. The material was acid-leached in 0.5M H2SO4 solution for 24 h, then placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a heating rate of 5°C / min. The material was heated under flowing nitrogen for 2 h to obtain the ferrocenium-doped MOF-derived metal carbide electrocatalyst, which is a dodecahedral composite material and is denoted as Fe3C-FeN / CH.

[0054] Example 4

[0055] The preparation method of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst proposed in the present invention comprises the following steps:

[0056] S1: Weigh 20 mg of the ZIF-8 precursor in Example 1, place it in a beaker, and dissolve it in 2 mL of anhydrous methanol solution to form a precursor solution; weigh 5 mg of ferrocene monocarboxylic acid, place it in a beaker, and dissolve it in 2 mL of DMF solution to obtain a uniform clear solution;

[0057] S2: Add the clarified solution in S1 to the precursor solution in S1 at room temperature, and stir ultrasonically for 30 min to mix the materials evenly to obtain a reaction solution;

[0058] S3: The reaction solution in S2 was placed in a high-pressure reactor for hydrothermal reaction at 100°C for 24 hours;

[0059] S4: The hydrothermal suspension was centrifuged, washed, and dried at a speed of 10,000 r / min for 5 minutes and at a drying temperature of 45°C for 10 hours. 20 mg of the dried material was placed in a porcelain boat, placed in a tube furnace, and heated to 900°C at a heating rate of 4°C / min. The mixture was heated under flowing nitrogen for 2.5 hours. The mixture was acid-leached in a 0.3M H2SO4 solution for 20 hours, then placed in a porcelain boat, placed in a tube furnace, and heated to 900°C at a heating rate of 4°C / min. The mixture was heated under flowing nitrogen for 2.5 hours to obtain the ferrocene-doped MOF-derived metal carbide electrocatalyst, which is a dodecahedral composite material.

[0060] Example 5

[0061] The preparation method of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst proposed in the present invention comprises the following steps:

[0062] S1: Weigh 20 mg of the ZIF-8 precursor in Example 1, place it in a beaker, and dissolve it in 2 mL of anhydrous methanol solution to form a precursor solution; weigh 5 mg of ferrocene monocarboxylic acid, place it in a beaker, and dissolve it in 2 mL of DMF solution to obtain a uniform clear solution;

[0063] S2: Add the clarified solution in S1 to the precursor solution in S1 at room temperature, and stir ultrasonically for 30 min to mix the materials evenly to obtain a reaction solution;

[0064] S3: The reaction solution in S2 was placed in a high-pressure reactor for hydrothermal reaction at 100°C for 20 h;

[0065] S4: The hydrothermal suspension was centrifuged, washed, and dried at a speed of 6000 r / min for 4 minutes and at a drying temperature of 55°C for 4 hours. 20 mg of the dried material was placed in a porcelain boat, placed in a tube furnace, and heated to 950°C at a heating rate of 3°C / min. The mixture was heated under flowing nitrogen for 1.5 hours. The mixture was acid-leached in a 0.6M H2SO4 solution for 30 hours, then placed in a porcelain boat, placed in a tube furnace, and heated to 950°C at a heating rate of 3°C / min. The mixture was heated under flowing nitrogen for 1.5 hours to obtain the ferrocene-doped MOF-derived metal carbide electrocatalyst, which is a dodecahedral composite material.

[0066] Depend on Figure 2 It can be seen that when the precursor is not added with iron salt, the sample is dodecahedral and has a small size ( Figure 2 a), When metallic iron is added, the MOF sample presents a similar dodecahedron ( Figure 2 b). In addition, after high-temperature calcination, it was found that the catalyst maintained its intact dodecahedron and was not destroyed ( Figure 2 c) The MOF sample was not damaged after high-temperature calcination, indicating that the sample has good thermal stability.

[0067] For the ZnFc-MOF-M derived composite Fe3C-FeN / CM, the morphology and composition of the product of Example 2 were further discussed using TEM. Transmission electron microscopy (TEM) ( Figure 3 ab) analysis, all samples basically maintain the morphology of the precursor without change, but the particle size is reduced. Figure 3 The HRTEM image of c shows that the spacing between the lattice fringes is 0.201 nm, corresponding to the (103) crystal plane, indicating the presence of Fe3C nanocrystals. In addition, the presence of (103) and (121) crystal planes in the selected lattice image further proves the existence of Fe3C ( Figure 3 cd).

[0068] The oxygen reduction performance of the sample was characterized using a three-electrode system on a CHI760D electrochemical workstation and a rotating ring disk electrode (RDE). 5 mg of the sample obtained in the experiment was weighed, 480 μL of ethanol, 480 μL of H2O and 40 μL of perfluorosulfonic acid (Nafion) solution were added, and ultrasonicated for 30 minutes to completely disperse it. The sample suspension was evenly dripped onto the rotating ring disk electrode twice, 5 μL each time, and dried with a baking lamp. In the three-electrode system, the working electrode was a disk electrode, the counter electrode was a graphite electrode, and the reference electrode was a saturated calomel electrode (SCE). The electrolyte used was an O2-saturated 0.1 M KOH solution (pH = 13). The potential used in this study was calculated using the formula E RHE =ESCE +0.244+0.0591×pH, converted to the corresponding reversible hydrogen electrode (RHE) value, where E SCE is the potential applied to the SCE reference electrode. Rotating ring-disk electrode measurements were performed at various rotational speeds from 400 rpm to 2025 rpm. Long-term stability testing was performed using chronopotentiometry. A zinc-air battery using zinc powder, 6.0 M KOH solution, and catalyst supported on a nickel foam substrate was used to record the ORR polarization curve using a linear potential sweep at a scan rate of 10 mV / s. Long-term stability testing and methanol toxicity testing were performed using chronoamperometry.

[0069] The ORR performance of the product in Example 2 is as follows: Figure 4 As shown in a, its half-wave potential E 1 / 2 =0.941V, limiting current J L =6.31mA / cm 2 ; Tafel slope is 97mV / dec( Figure 4 b) From Figure 4 c It can be seen that after the introduction of 1 mL of methanol in 200 s, the performance of Fe3C-FeN / CM has almost no change, indicating that Fe3C-FeN / CM has strong resistance to methanol poisoning. In addition, the ORR stability of the catalyst was tested at a voltage of 0.8 V, and the results showed that Figure 4 In Figure d, after 24 hours of continuous reaction, the ORR current retention rate was 92.6%, demonstrating the excellent ORR stability of the catalyst. Long-term durability is an important criterion for evaluating catalyst performance. Figure 4 The LSV curve (shown in the figure after 27h) of the e was tested at 1600 rpm and the initial LSV curve (shown in the figure at initial) differed by 12 mV, which confirmed that one of its active sites was Fe-N x .

[0070] In addition, the performance and stability of the disposable zinc-air battery (ZAB) of the catalyst prepared in Example 2 were further tested. Figure 5 As shown in a, the catalyst is at 420 mA / cm 2 The peak power density is 348mW / cm 2 , exceeding the peak power density (300 mA / cm 2 164mW / cm 2 ). Then, at 10 mA / cm 2 The specific capacity of the assembled primary battery was measured. If normalized to the consumed mass of zinc, the specific capacity of Fe3C-FeN / CM is 843 mAh / g Zn ( Figure 5b), higher than the 652 mAh / g of commercially available Pt / C (20 wt%) Zn At 10mA / cm 2 When the Zn-air battery assembled by Fe3C-FeN / CM has an initial potential of 1.414 V, the potential can maintain good stability after 120 hours of continuous operation, with a decay rate of 8.8% ( Figure 5 c), indicating that Fe3C-FeN / NC-M has good ORR electrocatalytic stability in actual ZAB. In order to study the rate performance of the battery, the current density was 2 to 20 mA / cm 2 The discharge test was carried out under the conditions of Figure 5 d). Compared with the commercial Pt / C (20 wt%) based ZAB, the Fe3C-FeN / CM assembled ZAB has a higher conductivity than the ZAB based on the Fe3C-FeN / CM when the ZAB returns to 2.0 mA / cm 2 It shows a smaller voltage drop of only 1.0% when the Fe3C-FeN / CM is used as the oxygen catalyst for ZAB cathode, indicating that the Fe3C-FeN / CM has an ideal durability and excellent recovery performance.

[0071] Comparative Example 1

[0072] A method for preparing a MOF-derived metal carbide electrocatalyst comprises the following steps:

[0073] S1: Weigh 20 mg of the ZIF-8 precursor prepared in Example 1 and place it in a beaker, then dissolve it in 2 mL of anhydrous methanol solution to form a suspension;

[0074] S2: The suspension in S1 was centrifuged, washed, and dried at 8000 rpm for 3 minutes and at 50°C for 12 hours. 20 mg of the dried material was placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a rate of 5°C / min. The mixture was then heated under flowing nitrogen for 2 hours. The mixture was then acid-leached in a 0.5 M H2SO4 solution for 24 hours, then placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a rate of 5°C / min. The mixture was then heated under flowing nitrogen for 2 hours to yield a dodecahedral composite material, designated N / C.

[0075] Comparative Example 2

[0076] A method for preparing a ferrocene-doped MOF-derived metal carbide electrocatalyst comprises the following steps:

[0077] S1: Weigh 20 mg of the ZIF-8 precursor prepared in Example 1 and place it in a beaker; weigh 5 mg of ferrocene monocarboxylic acid and place it in a beaker; pour the powders from the two beakers into a mortar in turn, grind and mix to obtain a uniform mixed powder;

[0078] S2: 20 mg of the mixed ZnFc-MOF-mix was placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a rate of 5°C / min. The mixture was heated under flowing nitrogen for 2 hours. The mixture was acid-leached in a 0.5 M H2SO4 solution for 24 hours, then placed in a porcelain boat, placed in a tube furnace, and heated to 920°C at a rate of 5°C / min. The mixture was heated under flowing nitrogen for 2 hours to obtain a dodecahedral composite material, designated Fe3C-FeN / C-mix.

[0079] Comparative Example 3

[0080] The only difference from Example 2 is that 5 mg of ferrocene is used instead of ferrocene monocarboxylic acid to carry out the hydrothermal reaction.

[0081] The LSV performance of ORR was measured according to the above method, E 1 / 2 =0.85V.

[0082] Comparative Example 4

[0083] The preparation method of a ferrocene-doped MOF-derived metal carbide electrocatalyst includes the following steps: 6.16 g of 2-methylimidazole is weighed and dissolved in 150 ml of methanol (Solution A), 5.95 g of Zn(NO₃)₂·6H₂O is weighed and dissolved in 150 ml of methanol (Solution B), the completely dissolved Solution A is added to Solution B, and 5 mg of ferrocene monocarboxylic acid is then added. The mixed solution is placed in a reactor at 100°C for 12 hours. The hydrothermal suspension is centrifuged, washed, and dried at 8000 rpm for 3 minutes and at 50°C for 12 hours. The dried material is placed in a porcelain boat and placed in a tube furnace. The sample is heated to 920°C at a rate of 5°C / min, maintained at 920°C for 2 hours under flowing nitrogen, and then naturally cooled to room temperature to obtain the metal carbide electrocatalyst.

[0084] Figure 6 The LSV curves of the catalysts prepared in Examples 1-3 of the present invention and the materials prepared in Comparative Examples 1-2 are shown in FIG. Figure 6 It can be seen that the metal carbide electrocatalyst obtained in the present invention has the best ORR performance, and the half-wave potential of Fe3C-FeN / CM is 0.941 V, which is higher than Fe3C-FeN / CL (0.917 V), Fe3C-FeN / CH (0.912 V), Fe3C-FeN / C-mix (0.913 V), and N / C (0.746 V).

[0085] Figure 7 The SEM image of the material prepared in Comparative Example 4 of the present invention is Figure 7It can be seen that the purity of the material obtained by doping ferrocene in one step in Comparative Example 4 is poor.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a ferrocenyl-doped MOF-derived metal carbide electrocatalyst, characterized in that: The following steps are involved: S1, dissolving ZIF-8 in anhydrous methanol to obtain solution A; Dissolve ferrocene monocarboxylic acid in DMF to obtain solution B; S2. Mixing solution A and solution B uniformly to obtain a reaction solution, and subjecting the reaction solution to a hydrothermal reaction; the mass ratio of ZIF-8 to ferrocene monocarboxylic acid in the reaction solution is 20:2-10; S3, centrifuging, washing, drying, calcining and carbonizing the product obtained after the reaction in S2 to obtain the ferrocene-doped MOF-derived metal carbide electrocatalyst; The calcination process includes: placing the dried material into a porcelain boat, placing it in a tube furnace and performing primary heating and calcination under the protection of inert gas; After acid leaching in 0.3-0.6M H2SO4 solution for 20-30 hours, the mixture is placed in a porcelain boat and placed in a tube furnace for secondary heating and calcination under the same conditions as the primary heating and calcination.

2. The method for preparing a ferrocenyl-doped MOF-derived metal carbide electrocatalyst according to claim 1, characterized in that: In S1, the mass volume ratio of ZIF-8 and anhydrous methanol is 20 mg:2 mL.

3. The method for preparing a ferrocenyl-doped MOF-derived metal carbide electrocatalyst according to claim 1, characterized in that: In S1, the mass volume ratio of ferrocene monocarboxylic acid and DMF is 2-10 mg:2 mL.

4. The method for preparing a ferrocenyl-doped MOF-derived metal carbide electrocatalyst according to claim 1, characterized in that: In S2, the temperature of the hydrothermal reaction is 100°C and the time is 12-24 hours.

5. The method for preparing a ferrocenyl-doped MOF-derived metal carbide electrocatalyst according to claim 1, wherein: In S3, the centrifugal conditions are: rotation speed 6000-10000 r / min, time 3-5 min; the drying conditions are: temperature 45-55° C., time 4-12 h.

6. The method for preparing a ferrocenyl-doped MOF-derived metal carbide electrocatalyst according to claim 1, characterized in that: The temperature of the primary heating calcination and the secondary heating calcination is 900-950° C., the time is 1.5-2.5 hours, and the heating rate is 3-5° C. / min.

7. A ferrocenyl-doped MOF-derived metal carbide electrocatalyst, characterized by: The electrocatalyst is prepared by the method for preparing a ferrocenium-doped MOF-derived metal carbide electrocatalyst according to any one of claims 1 to 6.

8. Use of the ferrocenyl-doped MOF-derived metal carbide electrocatalyst as claimed in claim 7 as an oxygen reduction catalyst in a zinc-air battery.

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