Conductive metal organic framework electrocatalyst as well as preparation method and application thereof
By controlling the mixed solution of organic ligand compounds and metal precursors under specific conditions, a conductive metal organic framework catalyst with regular rod morphology is prepared, which solves the problems of poor conductivity and structural damage, and achieves efficient catalytic activity and stability of oxygen precipitation, which is suitable for electrolytic water and fuel cell applications.
Patent Information
- Application Number
- CN202410036667.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-09
- Publication Date
- 2025-07-11
AI Technical Summary
The existing metal organic frame materials have poor conductivity in the electrolytic water oxygen precipitation reaction, and the heat treatment process destroys the porous structure, resulting in the catalytic active site being less likely to be exposed, limiting the improvement of catalytic activity.
By controlling the mixed solution of organic ligand compound and metal precursor ultrasonic treatment at a specific temperature and stirring rate, a conductive metal organic framework catalyst with a regular rod-shaped morphology was prepared, and a continuous conductive network was formed using a benzene ring π conjugated structure to improve conductivity and catalytic performance.
The prepared catalyst has high conductivity, good electrochemical stability and excellent oxygen precipitation catalytic activity. It has rich raw materials and low cost, making it suitable for large-scale production.
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Figure CN120289803A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of electrocatalysts, and in particular, to a conductive metal-organic framework electrocatalyst, a preparation method thereof, and an application thereof. Background Art
[0002] Alkaline water electrolysis has the advantages of easy operation, low equipment cost, and long service life, and is currently a widely used technology for converting renewable energy into hydrogen energy. Water electrolysis includes two half-reactions: oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Among them, the oxygen evolution reaction at the anode of water electrolysis involves the transfer of four electrons and the formation of an O=O double bond, and the reaction kinetic process is slow, requiring a catalyst to catalyze and reduce the reaction energy. Therefore, the development of high-performance and low-cost oxygen evolution catalysts is of great significance for the large-scale application of water electrolysis technology.
[0003] Currently, reported catalysts for the oxygen evolution reaction at the anode of water electrolysis include noble metal catalysts (such as iridium, ruthenium, and their oxides) and non-noble metal catalysts (such as metal hydroxides, metal sulfides, metal phosphides, metal-organic framework materials, etc.). The noble metals iridium and ruthenium are costly and scarce in reserves, which limits their application in the field of water electrolysis. Therefore, the development of non-noble metal catalysts is of great significance for promoting the large-scale development of water electrolysis.
[0004] In recent years, metal-organic framework (MOFs) materials have been widely used in the field of oxygen evolution reaction of water electrolysis due to their highly adjustable composition, microstructure, and pore structure. Currently, most MOFs materials have poor conductivity due to the coordination mode of metals and ligands. Generally, heat treatment is required for MOFs materials to generate carbon or metal compounds to improve their conductivity for electrocatalytic applications. However, the heat treatment process will destroy the porous structure of MOFs, which is not conducive to reaction mass transfer, and causes the intrinsic active metal sites to be submerged inside the MOFs structure, which is not conducive to the full exposure of active sites, limiting the further improvement of catalytic activity. Summary of the Invention
[0005] The purpose of the present disclosure is to provide a conductive metal-organic framework electrocatalyst, a preparation method thereof, and an application thereof. The catalyst prepared by this method has a high conductivity, high catalytic performance, good electrochemical stability, and the raw materials for preparing the catalyst are rich in reserves, low in cost, and can be scaled up for production.
[0006] To achieve the above purpose, the first aspect of the present disclosure provides a preparation method of a conductive metal-organic framework catalyst, the method comprising the following steps:
[0007] S1. Mix an organic ligand compound, a metal precursor, and a solvent to obtain a first mixed solution;
[0008] S2. After subjecting the first mixture to ultrasonic treatment, carry out the reaction under target reaction conditions;
[0009] Among them, the target reaction conditions include: the temperature is 80 - 100 °C, the stirring rate is 200 - 400 rmp, and the time is 6 - 12 h; the organic ligand compound contains a benzene ring.
[0010] Optionally, the organic ligand compound is selected from one or more of 2,3,6,7,10,11 - hexahydroxytriphenylene, 2,3,6,7,10,11 - hexaaminotriphenyl hexahydrochloride, 2,3,6,7,10,11 - hexamercaptotriphenylene, 2,3,7,8,12,13 - hexahydroxy - mesitylene, hexahydroxybenzene, and 2,3,7,8,12,13 - hexahydroxy - tricycloquinazoline; the metal precursor is selected from transition metal acetates. Preferably, the metal precursor is selected from one or more of Co(CH3COO)2·4H2O, Cu(CH3COO)2·4H2O, Ni(CH3COO)2·4H2O, Mn(CH3COO)2·4H2O, Cr(CH3COO)2·4H2O, Fe(CH3COO)2, Zn(CH3COO)2·2H2O, La(CH3COO)3·1.5H2O, and Y(CH3COO)3·4H2O.
[0011] Optionally, in step S1, the molar ratio of the organic ligand compound to the metal precursor is 1:(1 - 4); the weight ratio of the solvent, organic ligand compound, and metal precursor is (0.1 - 0.5):(0.4 - 0.5):1; preferably, in the first mixture, the molar concentration of the organic ligand compound is 0.006 - 0.02 mol / L; the molar concentration of the metal precursor is 0.02 - 0.04 mol / L; among them, the solvent includes an organic solvent and water, and the volume ratio of the organic solvent to water is 1:(1 - 10); preferably, the organic solvent is selected from one or more of methanol, ethanol, N,N - dimethylformamide, N,N - dimethylacetamide, chloroform, toluene, acetone, and chloromethane.
[0012] Optionally, in step S2, the target reaction conditions include: the temperature is 80 - 90 °C, the stirring rate is 300 - 400 rmp, and the time is 8 - 10 h; the conditions of the ultrasonic treatment include: the temperature is 21 - 30 °C, and the time is 0.1 - 2 h.
[0013] Optionally, the method further includes: after cooling the material after the reaction in step S2 for 1-3 h, subjecting the cooled material to filtration treatment and washing treatment, and then subjecting the solid material obtained after the washing treatment to drying treatment; wherein, the washing treatment includes: washing the solid material obtained after the filtration treatment 1-5 times with water and ethanol; the conditions of the drying treatment include: the temperature is 60-100 °C and the time is 3-8 h.
[0014] The second aspect of the present disclosure provides a conductive metal-organic framework catalyst prepared by the method described in the first aspect.
[0015] The third aspect of the present disclosure provides a conductive metal-organic framework catalyst, the catalyst comprising a metal-organic framework material, the metal-organic framework material comprising transition metal ions and an organic ligand, the organic ligand containing a benzene ring;
[0016] Based on the total weight of the catalyst, the content of the organic ligand is 60-80% by weight, and the content of the metal ions is 20-40% by weight;
[0017] The BET specific surface area of the catalyst is 400-600 m 2 / g.
[0018] Optionally, based on the total weight of the catalyst, the content of the organic ligand is 60-70% by weight, and the content of the transition metal ions is 30-40% by weight; the catalyst has a rod-like morphology, the average length of the catalyst is 300-400 nm, and the average diameter is 40-60 nm. Preferably, the average length of the catalyst is 300-350 nm and the average diameter is 40-55 nm; the BET specific surface area of the catalyst is 500-600 m 2 / g; preferably, the conductivity of the catalyst is 10 -6 -10 -2 S cm -1 .
[0019] Optionally, the organic ligand is selected from one or more of triphenylene-based organic ligands, preferably one or more of 2,3,6,7,10,11-hexahydroxytriphenylene, 2,3,6,7,10,11-hexaminotriphenylene hexahydrochloride, 2,3,6,7,10,11-hexamercaptotriphenylene, 2,3,7,8,12,13-hexahydroxytriphenylmethane, hexahydroxybenzene, and 2,3,7,8,12,13-hexahydroxytriquinazoline; the transition metal is selected from one or more of Co, Cu, Ni, Mn, Cr, Fe, Zn, La, and Y.
[0020] The fourth aspect of the present disclosure provides an application of the catalyst described in the second aspect or the third aspect in the oxygen evolution reaction and / or the nitrogen reduction reaction.
[0021] Through the above technical solutions, the present disclosure provides a conductive metal-organic framework electrocatalyst, its preparation method and application, which have the following advantages:
[0022] (1) The particles of the catalyst prepared in the present disclosure exhibit a relatively regular rod-like structure, with a uniform size distribution, a low overpotential, high electrochemical stability, high conductivity, and excellent oxygen evolution catalytic activity.
[0023] (2) The preparation method of the present disclosure is simple and controllable, and the raw materials have abundant reserves, low cost, and can be scaled up for production.
[0024] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation section. Description of the Drawings
[0025] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification, and are used together with the following specific implementation to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:
[0026] Figure 1 is the scanning electron microscope image of catalyst A in Example 1.
[0027] Figure 2 is the oxygen evolution performance graph of catalyst A in Example 1.
[0028] Figure 3 is the scanning electron microscope image of catalyst B in Example 2.
[0029] Figure 4 is the oxygen evolution performance graph of catalyst C in Example 3. Specific Embodiments
[0030] The following will describe the specific embodiments of the present disclosure in detail with reference to the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.
[0031] The first aspect of the present disclosure provides a preparation method of a conductive metal-organic framework catalyst, the method comprising the following steps:
[0032] S1. Mix an organic ligand compound, a metal precursor and a solvent to obtain a first mixed solution;
[0033] S2. After subjecting the first mixed solution to ultrasonic treatment, carry out a reaction under target reaction conditions;
[0034] Among them, the target reaction conditions include: the temperature is 80-100 °C, the stirring rate is 200-400 rmp, and the time is 6-12 h; the organic ligand compound contains a benzene ring.
[0035] In the present disclosure, after ultrasonic treatment, the organic ligand and the metal precursor are reacted. By controlling the reaction temperature, stirring rate and time, the particles of the conductive metal-organic framework catalyst prepared after the reaction of the organic ligand and the metal precursor can have a regular rod-like morphology. In a preferred embodiment of the present disclosure, the target reaction conditions include: the temperature is 80-90 °C, the stirring rate is 300-400 rmp, and the time is 8-10 h.
[0036] In one embodiment of the present disclosure, the organic ligand compound is selected from one or more of 2,3,6,7,10,11-hexahydroxytriphenylene, 2,3,6,7,10,11-hexaminotriphenyl hexahydrochloride, 2,3,6,7,10,11-hexamercaptotriphenylene, 2,3,7,8,12,13-hexahydroxytrimethylbenzene, hexahydroxybenzene and 2,3,7,8,12,13-hexahydroxytricycloquinazoline. The metal precursor is selected from transition metal acetates. Preferably, the metal precursor is selected from one or more of Co(CH3COO)2·4H2O, Cu(CH3COO)2·4H2O, Ni(CH3COO)2·4H2O, Mn(CH3COO)2·4H2O, Cr(CH3COO)2·4H2O, Fe(CH3COO)2, Zn(CH3COO)2·2H2O, La(CH3COO)3·1.5H2O and Y(CH3COO)3·4H2O.
[0037] In the present disclosure, the organic ligand compound has a π-conjugated rigid structure containing a benzene ring. The functional groups in the organic ligand compound can combine with a metal having an asymmetric electron center. In the organic ligand compound, the presence of a large number of benzene rings is more conducive to regulating the charge balance inside the catalyst, enabling a continuous conductive network in the structure of the metal-organic framework catalyst, thereby having a high charge delocalization to obtain a high conductivity. Moreover, each organic ligand compound also contains 6 functional groups, and the functional groups can be selected from at least one of hydroxyl, amino, and mercapto groups. Among them, the CAS number of 2,3,6,7,10,11-hexahydroxytriphenylene is 4877-80-9, the CAS number of 2,3,6,7,10,11-hexaminotriphenyl hexahydrochloride is 1350518-27-2, the CAS number of 2,3,6,7,10,11-hexamercaptotriphenylene is 100077-38-1, the CAS number of 2,3,7,8,12,13-hexahydroxytrimethylbenzene is 4877-80-9, the CAS number of hexahydroxybenzene is 608-80-0, and the CAS number of 2,3,7,8,12,13-hexahydroxytricycloquinazoline is 148494-98-8.
[0038] According to the present disclosure, the molar ratio of the organic ligand compound to the metal precursor can vary within a relatively large range. In one embodiment of the present disclosure, in step S1, the molar ratio of the organic ligand compound to the metal precursor is 1:(1 - 4), preferably 1:(1 - 3). In the present disclosure, when the molar ratio of the organic ligand compound to the metal precursor is within the range of the present disclosure, it is more conducive to the formation of a more regular rod-like structure of the catalyst particles, which can further promote the stability of the catalyst.
[0039] According to the present disclosure, the weight ratio of the solvent, organic ligand compound, and metal precursor can vary within a relatively large range. In one embodiment of the present disclosure, the weight ratio of the solvent, organic ligand compound, and metal precursor is (0.1 - 0.5):(0.4 - 0.5):1. Among them, the solvent includes an organic solvent and water, and the volume ratio of the organic solvent to water is 1:(1 - 10); in the present disclosure, the organic solvent can be selected from conventional reaction solvents in the art. In a preferred embodiment of the present disclosure, the organic solvent is selected from one or more of methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, toluene, acetone, and methyl chloride.
[0040] In the present disclosure, the organic ligand compound and the metal precursor have high solubility in the organic solvent in the above embodiments. When the weight ratio of the solvent, the organic ligand compound, and the metal precursor is within the range of the above embodiments, it is more conducive to the coordination of metal ions in the metal precursor and the organic ligand compound, and more conducive to the formation of a catalyst with regular structure and uniform size, and its electrocatalytic performance is more excellent. In a preferred embodiment of the present disclosure, the molar concentration of the organic ligand compound is 0.006 - 0.02 mol / L; the molar concentration of the metal precursor is 0.02 - 0.04 mol / L.
[0041] In an embodiment of the present disclosure, the conditions of the ultrasonic treatment include: the temperature is 21 - 30 °C, and the time is 0.1 - 2 h. In the present disclosure, the device used for ultrasonic treatment can be a conventional ultrasonic instrument in the art, which will not be elaborated here.
[0042] In an embodiment of the present disclosure, the method further includes: after cooling the material after the reaction in step S2 for 1 - 3 h, subjecting the cooled material to filtration treatment and washing treatment, and then subjecting the solid material obtained after the washing treatment to drying treatment.
[0043] In the present disclosure, the temperature of the cooled material is about 15 - 25 °C. In an embodiment of the present disclosure, the washing treatment includes: washing the solid material obtained after the filtration treatment with water and ethanol for 1 - 5 times. In an embodiment of the present disclosure, the conditions of the drying treatment include: the temperature is 60 - 100 °C, and the time is 3 - 8 h. Among them, the device used for drying treatment can be a conventional drying oven in the art, which will not be elaborated here. The filtration treatment can use a conventional solid-liquid separation device in the art, such as a centrifuge or a funnel.
[0044] The second aspect of the present disclosure provides a conductive metal-organic framework catalyst prepared by the method described in the first aspect.
[0045] The third aspect of the present disclosure provides a conductive metal-organic framework catalyst, the catalyst includes a metal-organic framework material, the metal-organic framework material contains transition metal ions and an organic ligand, and the organic ligand contains a benzene ring;
[0046] Based on the total weight of the catalyst, the content of the organic ligand is 60 - 80% by weight, and the content of the metal ions is 20 - 40% by weight;
[0047] The BET specific surface area of the catalyst is 400 - 600 m 2 / g.
[0048] In the present disclosure, the particles of the catalyst have a rod-like morphology. The catalyst of the present disclosure employs an organic ligand with a π-conjugated rigid structure containing a benzene ring. The functional groups in the organic ligand can combine with metals having an asymmetric electron center. Due to the presence of a large number of benzene rings in the organic ligand, it is more conducive to regulating the charge balance inside the catalyst, enabling the structure of the metal-organic framework catalyst to have a continuous conductive network, thereby having a high degree of charge delocalization to obtain a high electrical conductivity. In addition, the catalyst has a specific secondary building unit, and the metals in the discrete layers in addition to the continuous layers can serve as potential reaction sites for anodic oxygen evolution (OER). Further, the metal elements and the organic ligand of the present disclosure can form a planar structure with hexagonal channels, and this structure can be stacked in an ABAB stacking manner along a specific direction to form a relatively regular rod-like structure with a uniform size distribution, which is beneficial to electron conduction and proton transfer and has excellent catalytic activity, especially oxygen evolution catalytic activity.
[0049] In a preferred embodiment of the present disclosure, based on the total weight of the catalyst, the content of the organic ligand is 60 - 70% by weight, and the content of the transition metal ions is 30 - 40% by weight. In a preferred embodiment of the present disclosure, the catalyst has a rod-like morphology, wherein the average length of the catalyst is 300 - 400 nm, and the average diameter is 40 - 60 nm. Preferably, the average length of the catalyst is 300 - 350 nm, and the average diameter is 40 - 55 nm. In a preferred embodiment of the present disclosure, the BET specific surface area of the catalyst is 500 - 600 m 2 / g.
[0050] The catalyst of the present disclosure has a high electrical conductivity. In one embodiment of the present disclosure, the electrical conductivity of the catalyst is 10 -6- 10 -2 S cm -1 .
[0051] In one embodiment of the present disclosure, the organic ligand is selected from one or more of triphenylene-based organic ligands, preferably one or more of 2,3,6,7,10,11-hexahydroxytriphenylene, 2,3,6,7,10,11-hexaminotriphenylene hexahydrochloride, 2,3,6,7,10,11-hexamercaptotriphenylene, 2,3,7,8,12,13-hexahydroxytriphenylmethane, hexahydroxybenzene, and 2,3,7,8,12,13-hexahydroxytriquinazoline; the transition metal is selected from one or more of Co, Cu, Ni, Mn, Cr, Fe, Zn, La, and Y.
[0052] In the present disclosure, a large number of benzene rings are present in the organic ligand, enabling it to endow the catalyst with better structural rigidity, which can effectively inhibit the dissolution of the metal in the catalyst. Even at a relatively high pH, the catalyst still exhibits excellent electrochemical stability.
[0053] The fourth aspect of the present disclosure provides the application of the catalyst described in the second aspect or the third aspect in the oxygen evolution reaction and / or the nitrogen reduction reaction.
[0054] In the present disclosure, due to the excellent catalytic performance of the catalyst of the present disclosure, the catalyst of the present disclosure can be applied to the anodic oxygen evolution reaction of alkaline water electrolysis, the cathodic reduction reaction of alkaline fuel cells and metal-air, as well as the nitrogen reduction reaction.
[0055] The following specific examples are used to further illustrate the present invention, but the scope of protection required by the present invention is not limited to the scope described in the examples.
[0056] The chemicals used in each example can be obtained through public commercial channels.
[0057] In the present disclosure, filtration is carried out using a conventional vacuum pump to separate solids from liquids.
[0058] The drying treatment in the present disclosure uses a conventional drying oven.
[0059] The instrument model used for scanning electron microscopy is JEOL 6701F.
[0060] The BET specific surface area is measured using an ASAP 2020 model physical adsorption instrument.
[0061] Example 1
[0062] Weigh 50 mg of 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP, 0.01 mol / L) and 114 mg of Co(CH3COO)2·4H2O (0.03 mol / L) and dissolve them in 14 ml of deionized water and 1.4 mL of N,N-dimethylacetamide to obtain a mixed solution.
[0063] Seal the container and place it in an ultrasonic cleaner for ultrasonic dispersion at 25 °C for 10 min. Then, place the reaction mixture in an 85 °C oil bath and stir at a speed of 300 rmp for 8 h.
[0064] After the reaction time ends, cool the flask for 2 h, filter the product, and wash the product with deionized water (3 × 50 mL) and ethanol (3 × 50 mL) three times.
[0065] Dry the washed solid product in an 80 °C oven and grind it to obtain catalyst A.
[0066] The scanning electron microscope characterization results of catalyst A are as follows Figure 1 shown. It can be seen from the figure that the particles of catalyst A have a regular rod-like morphology.
[0067] The oxygen evolution performance test of catalyst A is as follows Figure 2 shown. This figure shows that catalyst A has excellent electrocatalytic activity.
[0068] Example 2
[0069] The catalyst was prepared by the same method as in Example 1, except that 114 mg of Ni(CH3COO)2·4H2O (0.03 mol / L) was weighed. Catalyst B was obtained.
[0070] The scanning electron microscope characterization results of catalyst B are as follows Figure 3 shown. It can be seen from the figure that the particles of catalyst B have a regular rod-like morphology.
[0071] Example 3
[0072] The catalyst was prepared by the same method as in Example 1, except that the reaction mixture was placed in an 80 °C hot oil bath. Catalyst C was obtained.
[0073] The oxygen evolution performance test of catalyst C is as follows Figure 4 shown. This figure shows that catalyst C has excellent electrocatalytic activity.
[0074] Example 4
[0075] The catalyst was prepared by the same method as in Example 1, except that the reaction mixture was placed in a 95 °C hot oil bath and stirred at a speed of 200 rmp for 6 h. Catalyst D was obtained.
[0076] Example 5
[0077] The catalyst was prepared by the same method as in Example 1, except that 10 mg of 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP, 0.006 mol / L) and 150 mg of Co(CH3COO)2·4H2O (0.110 mol / L) were dissolved in 5 ml of deionized water and 0.5 mL of N,N-dimethylacetamide to obtain a mixed solution. Catalyst E was obtained.
[0078] Example 6
[0079] The catalyst was prepared in the same manner as in Example 1, except that 50 mg of 2,3,6,7,10,11 - hexahydroxytriphenylene (HHTP, 0.01 mol / L) and 301 mg of Co(CH3COO)2·4H2O (0.78 mol / L) were weighed. Catalyst F was obtained.
[0080] Example 7
[0081] The catalyst was prepared in the same manner as in Example 1, except that 57 mg of 2,3,6,7,10,11 - hexaaminotriphenylene hexahydrochloride (HITP, 0.007 mol / L) and 114 mg of Ni(CH3COO)2·4H2O (0.03 mol / L) were dissolved in 14 ml of deionized water and 1.4 mL of N,N - dimethylacetamide to obtain a mixed solution. Catalyst G was obtained.
[0082] Example 8
[0083] The catalyst was prepared in the same manner as in Example 1, except that 40 mg of 2,3,6,7,10,11 - hexamercaptotriphenylene (HTT, 0.006 mol / L) and 80 mg of Fe(CH3COO)2 (0.03 mol / L) were dissolved in 14 ml of deionized water and 1.4 mL of N,N - dimethylacetamide to obtain a mixed solution. Catalyst H was obtained.
[0084] Comparative Example 1
[0085] The catalyst was prepared in the same manner as in Example 1, except that the reaction mixture was placed in a hot oil bath at 60 °C. Catalyst I was obtained.
[0086] Comparative Example 2
[0087] The catalyst was prepared in the same manner as in Example 1, except that the reaction mixture was stirred in a hot oil bath for 1 h. Catalyst J was obtained.
[0088] Comparative Example 3
[0089] The catalyst was prepared in the same manner as in Example 1, except that the container was sealed and placed in an ultrasonic cleaner for ultrasonic dispersion at 25 °C for 180 min, and the stirring reaction was not carried out under oil bath conditions. Catalyst K was obtained.
[0090] Test Example
[0091] The catalysts A, B, C, D, E, F, G, H obtained in Examples 1 - 8 and the catalysts I, J, K obtained in Comparative Examples 1 - 3 were respectively tested for scanning electron microscopy, oxygen evolution performance and conductivity.
[0092] The average length and average diameter of the catalyst were measured by a scanning electron microscope, and both the average length and average diameter were the average values calculated from measuring 100 particles.
[0093] The BET specific surface area was determined by a ASAP 2020 physical adsorption analyzer.
[0094] The oxygen evolution performance test was carried out in 1 mol / L KOH, with a graphite rod as the counter electrode, a saturated Hg-HgO electrode as the reference electrode, and the catalyst as the working electrode. The overpotential at a current density of 10 mA / cm 2 was taken as the evaluation criterion, and the chronopotentiometry method was stably used for testing.
[0095] Test of electrical conductivity: It was tested by a Hall effect tester (RH2030, Phys Tech).
[0096] Electrochemical stability: Long-term electrolysis stability tests were carried out at a certain current density, and the changes in the polarization curves before and after the tests were compared. The change in the overpotential at a current density of 10 mA cm -2 was taken as the evaluation parameter.
[0097] The average length, average diameter, overpotential, and electrical conductivity of the above tests are listed in Table 1.
[0098] Table 1
[0099]
[0100]
[0101] As can be seen from Table 1, compared with the catalysts prepared by the methods of Comparative Examples 1-3, the catalysts prepared by the methods of Examples 1-4 and Examples 7, 8 of the present disclosure have obvious rod-like morphologies of the particles, and have a higher BET specific surface area, a lower overpotential, and a higher electrical conductivity.
[0102] Comparing Example 1 with Comparative Example 1, the reaction temperature in Comparative Example 1 is lower, which affects the formation of the rod-like morphology of the catalyst. Therefore, adopting the reaction temperature of the present disclosure can further promote the formation of the rod-like morphology of the catalyst particles.
[0103] Comparing Example 1 with Comparative Example 2, the reaction time in Comparative Example 2 is shorter, which affects the formation of the rod-like morphology of the catalyst particles. Therefore, adopting the reaction time of the present disclosure can further promote the formation of the rod-like morphology of the catalyst particles.
[0104] Comparing Example 1 with Comparative Example 3, the reaction temperature in Comparative Example 3 was lower and the reaction was carried out only under ultrasonic conditions, which affected the formation of the rod-like morphology of the catalyst particles. Therefore, adopting the reaction conditions of the present disclosure can further promote the formation of the rod-like morphology of the catalyst particles.
[0105] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0106] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.
[0107] Furthermore, any combination can be made among various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.
Claims
1. A preparation method of a conductive metal-organic framework catalyst, characterized in that, The method includes the following steps: S1. Mix an organic ligand compound, a metal precursor and a solvent to obtain a first mixed solution; S2. Subject the first mixed solution to ultrasonic treatment and then carry out a reaction under target reaction conditions; Among them, the target reaction conditions include: the temperature is 80 - 100 °C, the stirring rate is 200 - 400 rmp, and the time is 6 - 12 h; the organic ligand compound contains a benzene ring.
2. The method according to claim 1, characterized in that The organic ligand compound is selected from one or more of 2,3,6,7,10,11 - hexahydroxytriphenylene, 2,3,6,7,10,11 - hexaaminotriphenyl hexahydrochloride, 2,3,6,7,10,11 - hexamercaptotriphenylene, 2,3,7,8,12,13 - hexahydroxytrimethylbenzene, hexahydroxybenzene, and 2,3,7,8,12,13 - hexahydroxytricycloquinazoline; The metal precursor is selected from transition metal acetates. Preferably, the metal precursor is selected from one or more of Co(CH3COO)2·4H2O, Cu(CH3COO)2·4H2O, Ni(CH3COO)2·4H2O, Mn(CH3COO)2·4H2O, Cr(CH3COO)2·4H2O, Fe(CH3COO)2, Zn(CH3COO)2·2H2O, La(CH3COO)3·1.5H2O, and Y(CH3COO)3·4H2O.
3. The method according to claim 2, wherein In step S1, the molar ratio of the organic ligand compound to the metal precursor is 1:(1 - 4); The weight ratio of the solvent, the organic ligand compound, and the metal precursor is (0.1 - 0.5):(0.4 - 0.5):1; Preferably, in the first mixed solution, the molar concentration of the organic ligand compound is 0.006 - 0.02 mol / L; the molar concentration of the metal precursor is 0.02 - 0.04 mol / L; Among them, the solvent includes an organic solvent and water, and the volume ratio of the organic solvent to water is 1:(1 - 10); Preferably, the organic solvent is selected from one or more of methanol, ethanol, N,N - dimethylformamide, N,N - dimethylacetamide, chloroform, toluene, acetone, and methyl chloride.
4. The method according to claim 1, characterized in that, In step S2, the target reaction conditions include: the temperature is 80 - 90 °C, the stirring rate is 300 - 400 rmp, and the time is 8 - 10 h; The conditions of the ultrasonic treatment include: the temperature is 21 - 30 °C, and the time is 0.1 - 2 h.
5. The method according to claim 1, characterized in that, The method further includes: after cooling the material after the reaction in step S2 for 1 - 3 h, subjecting the cooled material to filtration treatment and washing treatment, and then subjecting the solid material obtained after the washing treatment to drying treatment; Among them, the washing treatment includes: washing the solid material obtained after the filtration treatment with water and ethanol for 1 - 5 times; The conditions of the drying treatment include: the temperature is 60 - 100 °C, and the time is 3 - 8 h.
6. A conductive metal - organic framework catalyst prepared by the method according to any one of claims 1 - 5.
7. A conductive metal-organic framework catalyst, characterized in that, The catalyst includes a metal-organic framework material, the metal-organic framework material contains transition metal ions and organic ligands, and the organic ligands contain benzene rings; Based on the total weight of the catalyst, the content of the organic ligand is 60-80% by weight, and the content of the transition metal ions is 20-40% by weight; The BET specific surface area of the catalyst is 400 - 600 m 2 / g.
8. The catalyst according to claim 7, wherein Based on the total weight of the catalyst, the content of the organic ligand is 60-70% by weight, and the content of the transition metal ions is 30-40% by weight; The catalyst has a rod-like morphology, the average length of the catalyst is 300-400 nm, and the average diameter is 40-60 nm. Preferably, the average length of the catalyst is 300-350 nm, and the average diameter is 40-55 nm; The BET specific surface area of the catalyst is 500 - 600 m 2 / g; Preferably, the conductivity of the catalyst is 10 -6 -10 -2 S cm -1 .
9. The catalyst according to claim 7, characterized in that, The organic ligand is selected from one or more of triphenylene-based organic ligands, preferably one or more of 2,3,6,7,10,11-hexahydroxytriphenylene, 2,3,6,7,10,11-hexamminetriphenylene hexahydrochloride, 2,3,6,7,10,11-hexamercaptotriphenylene, 2,3,7,8,12,13-hexahydroxytriphenylmethane, hexahydroxybenzene, and 2,3,7,8,12,13-hexahydroxytriquinazoline; The transition metal is selected from one or more of Co, Cu, Ni, Mn, Cr, Fe, Zn, La, and Y.
10. Use of the catalyst according to claim 5 or any one of claims 6-9 in the oxygen evolution reaction and / or the nitrogen reduction reaction.