A MOF-derived controllable transition metal phosphide electrocatalyst, its preparation method and application
By synthesizing CoFc-MOF by solvothermal method and controlling the phosphating time, a sea urchin-like controllable transition metal phosphide electrocatalyst was prepared, solving the problem of poor catalytic performance and achieving high efficiency and easy industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANHUI UNIV OF SCI & TECH
- Filing Date
- 2023-04-27
- Publication Date
- 2026-05-19
AI Technical Summary
Existing catalysts have poor catalytic performance in the field of electrocatalysis. In particular, many transition metal phosphides are prone to agglomeration, making it difficult to obtain the desired phosphide species. Furthermore, precious metal catalysts are expensive and have poor stability.
CoFc-MOF was synthesized via a solvothermal reaction using 1,1'-ferrocene dicarboxylic acid as a ligand. Subsequently, partial phosphating was performed using sodium hypophosphite in an inert atmosphere, and the phosphating time was controlled to prepare a sea urchin-like controllable transition metal phosphide electrocatalyst.
The prepared sea urchin-shaped electrocatalyst exhibits excellent electrocatalytic performance under alkaline conditions, improving catalytic kinetics and mass transfer rate. It is suitable for hydrogen evolution and oxygen evolution reactions in the complete splitting of water, and the process is simple and easy to industrialize.
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Figure CN116497370B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, specifically to a MOF-derived controllable transition metal phosphide electrocatalyst, its preparation method, and its application. Background Technology
[0002] Hydrogen has a high calorific value, three times that of gasoline, 3.9 times that of alcohol, and 4.5 times that of coke. The combustion product of hydrogen is water, making it one of the cleanest energy sources in the world. Water can also be used to produce hydrogen, thus achieving a circular economy. However, the most efficient catalysts currently are still precious metals, but these are scarce in nature, expensive, and unstable in alkaline media. Therefore, developing non-precious metal catalysts is of great significance. Transition metals, due to their low cost and after treatments such as phosphating, carburizing, and sulfidation, can exhibit excellent performance. Transition metal phosphides have been widely used in electrocatalysis, and many researchers are no longer satisfied with the catalytic effects of single-metal phosphides, and are beginning to focus on the synergistic effects of bimetallic or even multimetallic compounds to obtain better catalytic performance. However, multiple transition metal phosphides inevitably lead to aggregation, and it is difficult to obtain the desired phosphating species.
[0003] Chinese patent application CN113699536A discloses a metal phosphide electrocatalyst based on MOF, its preparation method, and its application. The preparation method includes the following steps: S1: Dissolve pyrimidine 4,6-dicarboxylic acid in DMF to form a ligand solution; S2: Add the metal salt to deionized water and stir until homogeneous to obtain a metal ion solution.
[0004] S3: The metal ion solution from S2 was added to the ligand solution from S1 at room temperature, and the mixture was sonicated for 46 min to ensure homogeneity, then allowed to stand for 46 h. S4: The suspension from S3 after standing was centrifuged and dried. S5: The dried material from S4 was calcined and phosphated to obtain a three-dimensional flower-like nanocomposite material. The three-dimensional flower-like bifunctional catalyst assembled from ultrathin N / C nanosheets exhibited excellent electrocatalytic hydrolysis for hydrogen and oxygen production under alkaline conditions (1.0 M KOH), but the product morphology was three-dimensional flower-like, indicating that the catalytic performance was still unsatisfactory.
[0005] Chinese patent application CN108190963A discloses a method for preparing a hollow CoFe2O4@C composite material with a secondary nanorod structure for lithium-ion battery electrode materials. The method first uses cobalt salt and ferrocene dicarboxylic acid to prepare a multi-level hollow ferrocene-based coordination polymer (Co-Fc-Hcps) via a solvothermal method. Then, the prepared Co-Fc-Hcps coordination polymer is calcined at high temperature in air to prepare a multi-level hollow CoFe2O4 material. Finally, the CoFe2O4@C multi-level hollow composite material is obtained by stirring with dopamine hydrochloride and calcining at high temperature in a nitrogen atmosphere. This composite material is then used as a novel energy storage electrode material and for magnetic applications. However, the prepared ferrocene-based coordination polymer has a multi-level hollow structure, and it is not used as a catalyst. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a sea urchin-shaped electrocatalyst with excellent catalytic performance and its preparation method.
[0007] The present invention solves the above-mentioned technical problems through the following technical means:
[0008] A method for preparing a MOF-derived controllable transition metal phosphide electrocatalyst includes the following steps: using 1,1'-ferrocene dicarboxylic acid as a ligand, N,N-dimethylformamide and methanol as solvents, and cobalt chloride as a metal salt, a solvothermal reaction is carried out to obtain CoFc-MOF; under an inert atmosphere, sodium hypophosphite is used as a phosphorus source to phosphate the obtained CoFc-MOF to obtain a sea urchin-like MOF-derived controllable transition metal phosphide electrocatalyst.
[0009] Preferably, the phosphating is partial phosphating.
[0010] Preferably, the preparation method of the MOF-derived controllable transition metal phosphide electrocatalyst includes the following steps:
[0011] S1: Dissolve 1,1'-ferrocene dicarboxylic acid in N,N-dimethylformamide to obtain solution A; dissolve cobalt chloride in methanol to obtain solution B;
[0012] S2: Add solution B to solution A to obtain a mixed solution, then place it in a hydrothermal reactor for a solvothermal reaction. After the reaction, separate the solid and liquid and dry to obtain CoFc-MOF.
[0013] S3: In an inert atmosphere, sodium hypophosphite is used as a phosphorus source to phosphate the obtained CoFc-MOF to obtain the MOF-derived controllable transition metal phosphide electrocatalyst.
[0014] Preferably, the cobalt chloride is cobalt chloride hexahydrate; the mass ratio of 1,1'-ferrocene dicarboxylic acid to cobalt chloride hexahydrate is 1:1.8-2.2.
[0015] Preferably, the volume ratio of N,N-dimethylformamide to methanol is 1-3:1; and the mass-volume ratio of 1,1'-ferrocene dicarboxylic acid to N,N-dimethylformamide is 1.5-2 mg:1 ml.
[0016] Preferably, the temperature of the solvothermal reaction is 110-130℃ and the time is 10-15h.
[0017] Preferably, the inert atmosphere is a nitrogen atmosphere or an argon atmosphere; the phosphating temperature is 350-450℃, the time is 5-120min, and the heating rate is 3-6℃ / min.
[0018] Preferably, the phosphating temperature is 400℃ and the time is 5-8 min; phosphating for 5-8 min generates Co2P.
[0019] Preferably, the phosphating temperature is 400°C and the time is 5 minutes.
[0020] Preferably, the method for phosphating the obtained CoFc-MOF using sodium hypophosphite as a phosphorus source in an inert atmosphere specifically includes the following steps: placing the obtained CoFc-MOF and sodium hypophosphite in different ceramic boats, placing them in a tube furnace, and carrying out the phosphating reaction after heating in an inert atmosphere.
[0021] Preferably, the mass ratio of CoFc-MOF to sodium hypophosphite is 1:10-30.
[0022] The present invention also proposes a MOF-derived controllable transition metal phosphide electrocatalyst, which is prepared by the aforementioned method for preparing MOF-derived controllable transition metal phosphide electrocatalyst.
[0023] This invention also proposes the application of the aforementioned MOF-derived controllable transition metal phosphide electrocatalyst as a catalyst for hydrogen evolution and oxygen evolution reactions in the total water splitting process.
[0024] The preparation method of this invention uses ferrocene-based ligands, and the resulting MOF has structural advantages, making it easy to obtain dispersed FeP. Furthermore, by controlling the phosphating time, CoP or Co2P can be obtained, and it can have a synergistic effect with FeP, which can improve catalytic kinetics and mass transfer rate, thereby enhancing the catalytic performance of the electrocatalyst.
[0025] Beneficial technical effects of the present invention:
[0026] (1) The present invention uses ferrocene-based ligands as precursors and adopts a strategy of controlling phosphating time for partial phosphating. The phosphating time is short, and the desired phosphated species can be obtained in a short phosphating time. The morphology is almost unchanged from the original MOF morphology. It is a sea urchin-like morphological material with a high specific surface area, which is beneficial for mass transfer.
[0027] (2) The sea urchin-like material prepared by this invention can be used as a catalyst for hydrogen evolution reaction and oxygen evolution reaction for the complete splitting of water, and has excellent electrochemical performance under alkaline conditions (1M KOH).
[0028] (3) The preparation process used in this invention is simple, easy to reproduce, and convenient for industrial production. Attached Figure Description
[0029] Figure 1 The images shown are SEM images of CoFc-MOF in Example 1 and the electrocatalysts in Examples 1 and 3 of the present invention; wherein, (a) and (b) are SEM images of CoFc-MOF at different magnifications, (c) is an SEM image of Co2P-FeP@C obtained by phosphating for five minutes in Example 1, and (d) is an SEM image of CoP-FeP-30@C obtained by phosphating for thirty minutes in Example 3.
[0030] Figure 2 The images show the TEM image (a), HRTEM image (b), and SAED (subplot in b) of Co2P-FeP@C obtained in Example 1 of this invention.
[0031] Figure 3 The XRD patterns of the products obtained in Examples 1-3 of this invention are shown below.
[0032] Figure 4 The LSV curves (a), Tafer slope (b), electrochemical active area (c), and stability curves (d, e) of CoFc-MOF in Example 1, the products of Examples 1-3, and the commercial Pt / C electrocatalyst as hydrogen evolution electrocatalysts are shown.
[0033] Figure 5 The LSV curves (a), Tafer slope (b), electrochemical active area (c), and stability curves (d, e) of CoFc-MOF in Example 1, the products of Examples 1-3, and the commercial RuO2 electrocatalyst as an oxygen evolution electrocatalyst are shown. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of 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 some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0035] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.
[0036] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.
[0037] In this embodiment of the invention, cobalt chloride hexahydrate and 1,1'-ferrocene dicarboxylic acid were purchased from Shanghai Maclean Biochemical Co., Ltd.; potassium hydroxide was purchased from Sinopharm Chemical Reagent Co., Ltd.; anhydrous methanol and N,N-dimethylformamide were purchased from Jiangsu Qiangsheng Functional Chemical Co., Ltd.; all the above raw materials were of analytical grade.
[0038] The scanning electron microscope (SEM) used in this invention was purchased from Kunshan Ultrasonic Instrument Co., Ltd.; the transmission electron microscope (TEM, JEM2100F) was purchased from NEC; the X-ray diffractometer (XRD, Shimadzu XRD-6000) was purchased from NEC Corporation; and the electrochemical workstation was purchased from Shanghai Chenhua Instrument Co., Ltd.
[0039] Example 1
[0040] The method for preparing MOF-derived controllable transition metal phosphide electrocatalysts proposed in this invention includes the following steps:
[0041] S1: Weigh 5 mg of 1,1'-ferrocene dicarboxylic acid and place it in a beaker. Then, measure 3 ml of N,N-dimethylformamide and add it to the beaker. Dissolve it by sonication to obtain solution A. Weigh 10 mg of cobalt chloride hexahydrate and place it in a beaker. Then, measure 1.5 ml of anhydrous methanol and add it to the beaker. Dissolve it by sonication to obtain solution B.
[0042] S2: Add solution B dropwise to solution A and sonicate for ten minutes to obtain a homogeneous mixed solution; place the mixed solution in an autoclave lined with polytetrafluoroethylene and then carry out a solvothermal reaction at 120℃ for 12 hours; centrifuge and dry the precipitate after the reaction to obtain CoFc-MOF. The centrifugation conditions are: rotation speed 8000 r / min, time 3 min, and drying conditions are: temperature 50℃, time 12 h.
[0043] S3: Phosphate the dried material from S2 under a nitrogen atmosphere for five minutes to obtain a sea urchin-like material, namely the MOF-derived controllable transition metal phosphide electrocatalyst, denoted as Co2P-FeP@C; the phosphating method specifically includes the following steps: 20 mg of the dried material from S2 is loaded into a ceramic boat, and 600 mg of sodium hypophosphite is placed in another ceramic boat. The two ceramic boats are placed in a tube furnace and heated to 400°C for 5 minutes under a nitrogen atmosphere at a heating rate of 5°C / min, and then cooled to room temperature at a cooling rate of 5°C / min.
[0044] Example 2
[0045] The method for preparing MOF-derived controllable transition metal phosphide electrocatalysts proposed in this invention includes the following steps:
[0046] S1: Weigh 5 mg of 1,1'-ferrocene dicarboxylic acid and place it in a beaker. Then, measure 3 ml of N,N-dimethylformamide and add it to the beaker. Dissolve it by sonication to obtain solution A. Weigh 10 mg of cobalt chloride hexahydrate and place it in a beaker. Then, measure 1.5 ml of anhydrous methanol and add it to the beaker. Dissolve it by sonication to obtain solution B.
[0047] S2: Add solution B dropwise to solution A and sonicate for ten minutes to obtain a homogeneous mixed solution; place the mixed solution in an autoclave lined with polytetrafluoroethylene and then carry out a solvothermal reaction at 120℃ for 12 hours; centrifuge and dry the precipitate after the reaction to obtain CoFc-MOF. The centrifugation conditions are: rotation speed 8000 r / min, time 3 min, and drying conditions are: temperature 50℃, time 12 h.
[0048] S3: Phosphate the dried material from S2 under a nitrogen atmosphere for 15 minutes to obtain a sea urchin-like material, namely the MOF-derived controllable transition metal phosphide electrocatalyst, denoted as CoP-FeP-15@C; the phosphating method specifically includes the following steps: 20 mg of the dried material from S2 is loaded into a ceramic boat, and 600 mg of sodium hypophosphite is placed in another ceramic boat. The two ceramic boats are placed in a tube furnace and heated to 400°C for 15 minutes under a nitrogen atmosphere at a heating rate of 5°C / min. Then, the temperature is lowered to room temperature at a cooling rate of 5°C / min.
[0049] Example 3
[0050] The method for preparing MOF-derived controllable transition metal phosphide electrocatalysts proposed in this invention includes the following steps:
[0051] S1: Weigh 5 mg of 1,1'-ferrocene dicarboxylic acid and place it in a beaker. Then, measure 3 ml of N,N-dimethylformamide and add it to the beaker. Dissolve it by sonication to obtain solution A. Weigh 10 mg of cobalt chloride hexahydrate and place it in a beaker. Then, measure 1.5 ml of anhydrous methanol and add it to the beaker. Dissolve it by sonication to obtain solution B.
[0052] S2: Add solution B dropwise to solution A and sonicate for ten minutes to obtain a homogeneous mixed solution; place the mixed solution in an autoclave lined with polytetrafluoroethylene and then carry out a solvothermal reaction at 120℃ for 12 hours; centrifuge and dry the precipitate after the reaction to obtain CoFc-MOF. The centrifugation conditions are: rotation speed 8000 r / min, time 3 min, and drying conditions are: temperature 50℃, time 12 h.
[0053] S3: The dried material from S2 is phosphated for 30 minutes under a nitrogen atmosphere to obtain a sea urchin-like material, namely the MOF-derived controllable transition metal phosphide electrocatalyst, denoted as CoP-FeP-30@C; the phosphating method specifically includes the following steps: 20 mg of the dried material from S2 is loaded into a ceramic boat, and 300 mg of sodium hypophosphite is placed in another ceramic boat. The two ceramic boats are placed in a tube furnace and heated to 400°C for 30 minutes under a nitrogen atmosphere at a heating rate of 5°C / min. Then, the temperature is lowered to room temperature at a cooling rate of 5°C / min.
[0054] Example 4
[0055] The method for preparing MOF-derived controllable transition metal phosphide electrocatalysts proposed in this invention includes the following steps:
[0056] S1: Weigh 5 mg of 1,1'-ferrocene dicarboxylic acid and place it in a beaker. Then, measure 3 ml of N,N-dimethylformamide and add it to the beaker. Dissolve it by sonication to obtain solution A. Weigh 9 mg of cobalt chloride hexahydrate and place it in a beaker. Then, measure 3 ml of anhydrous methanol and add it to the beaker. Dissolve it by sonication to obtain solution B.
[0057] S2: Add solution B dropwise to solution A and sonicate for ten minutes to obtain a homogeneous mixed solution; place the mixed solution in an autoclave lined with polytetrafluoroethylene and then carry out a solvothermal reaction at 110℃ for 15 hours; centrifuge and dry the precipitate after the reaction to obtain CoFc-MOF. The centrifugation conditions are: rotation speed 8000 r / min, time 3 min, and drying conditions are: temperature 50℃, time 12 h.
[0058] S3: Phosphate the dried material from S2 under a nitrogen atmosphere for 30 minutes to obtain a sea urchin-like material, namely the MOF-derived controllable transition metal phosphide electrocatalyst, denoted as CoP-FeP-30@C; the phosphating method specifically includes the following steps: 20 mg of the dried material from S2 is loaded into a ceramic boat, and then 400 mg of sodium hypophosphite is placed in another ceramic boat. The two ceramic boats are placed in a tube furnace and heated to 350°C for 30 minutes under a nitrogen atmosphere at a heating rate of 6°C / min, and then cooled to room temperature at a cooling rate of 6°C / min.
[0059] Example 5
[0060] The method for preparing MOF-derived controllable transition metal phosphide electrocatalysts proposed in this invention includes the following steps:
[0061] S1: Weigh 5 mg of 1,1'-ferrocene dicarboxylic acid and place it in a beaker. Then, measure 2.5 ml of N,N-dimethylformamide and add it to the beaker. Dissolve it by sonication to obtain solution A. Weigh 11 mg of cobalt chloride hexahydrate and place it in a beaker. Then, measure 1.5 ml of anhydrous methanol and add it to the beaker. Dissolve it by sonication to obtain solution B.
[0062] S2: Add solution B dropwise to solution A and sonicate for ten minutes to obtain a homogeneous mixed solution; place the mixed solution in an autoclave lined with polytetrafluoroethylene and then carry out a solvothermal reaction at 130℃ for 10 hours; centrifuge and dry the precipitate after the reaction to obtain CoFc-MOF. The centrifugation conditions are: rotation speed 8000 r / min, time 3 min, and drying conditions are: temperature 50℃, time 12 h.
[0063] S3: Phosphate the dried material from S2 under an argon atmosphere for 25 minutes to obtain a sea urchin-like material, namely the MOF-derived controllable transition metal phosphide electrocatalyst CoP-FeP-25@C. The phosphating method specifically includes the following steps: 20 mg of the dried material from S2 is loaded into a ceramic boat, and 100 mg of sodium hypophosphite is placed in another ceramic boat. The two ceramic boats are placed in a tube furnace and heated to 400°C for 25 minutes under an argon atmosphere at a heating rate of 3°C / min. Then, the temperature is lowered to room temperature at a cooling rate of 5°C / min.
[0064] Example 6
[0065] The method for preparing MOF-derived controllable transition metal phosphide electrocatalysts proposed in this invention includes the following steps:
[0066] S1: Weigh 5 mg of 1,1'-ferrocene dicarboxylic acid and place it in a beaker. Then, measure 3 ml of N,N-dimethylformamide and add it to the beaker. Dissolve it by sonication to obtain solution A. Weigh 10 mg of cobalt chloride hexahydrate and place it in a beaker. Then, measure 1 ml of anhydrous methanol and add it to the beaker. Dissolve it by sonication to obtain solution B.
[0067] S2: Add solution B dropwise to solution A and sonicate for ten minutes to obtain a homogeneous mixed solution; place the mixed solution in an autoclave lined with polytetrafluoroethylene and then carry out a solvothermal reaction at 120℃ for 12 hours; centrifuge and dry the precipitate after the reaction to obtain CoFc-MOF. The centrifugation conditions are: rotation speed 8000 r / min, time 3 min, and drying conditions are: temperature 50℃, time 12 h.
[0068] S3: The dried material from S2 is phosphated for 30 minutes under a nitrogen atmosphere to obtain a sea urchin-like material, namely the MOF-derived controllable transition metal phosphide electrocatalyst, denoted as CoP-FeP-30@C; the phosphating method specifically includes the following steps: 20 mg of the dried material from S2 is loaded into a ceramic boat, and 500 mg of sodium hypophosphite is placed in another ceramic boat. The two ceramic boats are placed in a tube furnace and heated to 400°C for 30 minutes under a nitrogen atmosphere at a heating rate of 5°C / min. Then, the temperature is lowered to room temperature at a cooling rate of 5°C / min.
[0069] Depend on Figure 1 It can be seen that the morphology of the sea urchin remains almost unchanged at different phosphating times.
[0070] Furthermore, the electrochemical performance of the samples was characterized using a CHI760D electrochemical workstation in a three-electrode system. The oxygen reduction performance of the samples was characterized using a three-electrode system on a CHI760D electrochemical workstation and a rotating ring-disk electrode (RDE). 0.5 mg of the experimental sample was weighed and 30 μl of conductive binder (3 ml N-methylpyrrolidone as solvent per 1 mg of polyvinylidene fluoride) was added. The mixture was sonicated for 30 minutes to ensure complete dispersion. The sample suspension was then uniformly dropped onto a graphite electrode (1 cm × 1 cm). In the three-electrode system, the graphite electrode was used as the counter electrode for the hydrogen evolution reaction, a platinum sheet as the counter electrode for the oxygen evolution reaction, and Hg / HgO was used as the reference electrode. The electrolyte was a 1 M KOH solution (pH = 13.8). The potential used in this study was determined using the formula E. RHE =E Hg / HgO +0.098 + 0.0591 × pH, converted to the corresponding value for the reversible hydrogen electrode (RHE), all measured current densities are IR compensated. The overpotentials (η) of HER and OER are calculated as follows: η OER =E RHE-1.23, η HER =E RHE -0.
[0071] For the electrocatalyst prepared by phosphating for five minutes in Example 1, the morphology and composition of the product were further discussed using TEM. Transmission electron microscopy (TEM) images are shown. Figure 2 The results show that the pyrolysis samples Co2P-FeP@C after heat treatment all retained their original sea urchin-like shape, and were composed of... Figure 2 The lattice structure and diffraction of b indicate that its phosphides are FeP and Co2P.
[0072] Depend on Figure 3 It can be seen that the phosphating species corresponding to different phosphating times in Examples 1-3 are different, changing from Co2P-FeP@C to CoP-FeP@C. As the phosphating time increases, the phosphating species ultimately remain unchanged.
[0073] Depend on Figure 4 As can be seen from a, the catalyst prepared in this invention, as a hydrogen evolution catalyst, has a small overpotential; Figure 4 b indicates that it has a smaller Tafer slope; from Figure 4 As shown in Figure c, it has a large Faraday active area. 4d is the overpotential before and after the 24-hour test, and 4e is the deviation from the initial voltage during the 24-hour test. As can be seen from the tests in Figures d and e, Co2P-FeP@C has good stability.
[0074] Depend on Figure 5 As can be seen from a, the catalyst prepared in this invention, as an oxygen evolution catalyst, has a small overpotential; Figure 5 b indicates that it has a smaller Tafer slope; from Figure 5 c indicates that it has a large Faraday active area; 5d is the overpotential before and after the 24-hour test, and 5e is the deviation from the initial voltage during the 24-hour test. Figure 5 The d and 5e tests show that Co2P-FeP@C has good stability.
[0075] in, Figure 4 b and Figure 5 In b, the colors of the curves represent substances that are respectively related to... Figure 4 a and Figure 5 a is the same.
[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a MOF-derived controllable transition metal phosphide electrocatalyst, characterized in that: The steps are as follows: CoFc-MOF is obtained by solvothermal reaction using 1,1'-ferrocene dicarboxylic acid as ligand, N,N-dimethylformamide and methanol as solvent, and cobalt chloride as metal salt; under an inert atmosphere, the obtained CoFc-MOF is phosphated using sodium hypophosphite as phosphorus source to obtain a sea urchin-like MOF-derived controllable transition metal phosphide electrocatalyst; the phosphating time is 5 min.
2. The method for preparing the MOF-derived controllable transition metal phosphide electrocatalyst according to claim 1, characterized in that: Includes the following steps: S1: Dissolve 1,1'-ferrocene dicarboxylic acid in N,N-dimethylformamide to obtain solution A; dissolve cobalt chloride in methanol to obtain solution B; S2: Add solution B to solution A to obtain a mixed solution, then place it in a hydrothermal reactor for a solvothermal reaction. After the reaction, separate the solid and liquid and dry to obtain CoFc-MOF. S3: In an inert atmosphere, sodium hypophosphite is used as a phosphorus source to phosphate the obtained CoFc-MOF to obtain the MOF-derived controllable transition metal phosphide electrocatalyst.
3. The method for preparing the MOF-derived controllable transition metal phosphide electrocatalyst according to claim 1 or 2, characterized in that: The cobalt chloride is cobalt chloride hexahydrate; the mass ratio of 1,1'-ferrocene dicarboxylic acid to cobalt chloride hexahydrate is 1:1.8-2.
2.
4. The method for preparing the MOF-derived controllable transition metal phosphide electrocatalyst according to claim 1 or 2, characterized in that: The volume ratio of N,N-dimethylformamide to methanol is 1-3:1; the mass-volume ratio of 1,1'-ferrocene dicarboxylic acid to N,N-dimethylformamide is 1.5-2 mg:1 ml.
5. The method for preparing the MOF-derived controllable transition metal phosphide electrocatalyst according to claim 1 or 2, characterized in that: The solvothermal reaction is carried out at a temperature of 110-130℃ for 10-15 hours.
6. The method for preparing the MOF-derived controllable transition metal phosphide electrocatalyst according to claim 1 or 2, characterized in that: The inert atmosphere is a nitrogen atmosphere or an argon atmosphere; the phosphating temperature is 350-450℃, and the heating rate is 3-6℃ / min.
7. The method for preparing the MOF-derived controllable transition metal phosphide electrocatalyst according to claim 1 or 2, characterized in that: The method for phosphating the obtained CoFc-MOF using sodium hypophosphite as a phosphorus source in an inert atmosphere specifically includes the following steps: the obtained CoFc-MOF and sodium hypophosphite are placed in different ceramic boats, placed in a tube furnace, and phosphating reaction is carried out after heating in an inert atmosphere.
8. The method for preparing the MOF-derived controllable transition metal phosphide electrocatalyst according to claim 1 or 2, characterized in that: The mass ratio of CoFc-MOF to sodium hypophosphite is 1:10-30.
9. A MOF-derived controllable transition metal phosphide electrocatalyst, characterized in that, It is prepared by the method for preparing MOF-derived controllable transition metal phosphide electrocatalysts as described in any one of claims 1-8.
10. The application of the MOF-derived controllable transition metal phosphide electrocatalyst as described in claim 9 as a catalyst for hydrogen evolution and oxygen evolution reaction in total water splitting.