A medium / high-entropy metal-organic framework material and a preparation method thereof

Abstract

The application provides a medium / high-entropy metal organic framework material and a preparation method thereof, wherein the configuration entropy (Delta S) of the medium-entropy metal organic framework material satisfies 1R < Delta S < 1.5R, the configuration entropy (Delta S) of the high-entropy metal organic framework material satisfies Delta S > 1.5R, R is a gas constant and is 8.314; the metal ions in the medium / high-entropy metal organic framework material are at least four kinds of magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, ruthenium, palladium, silver, cadmium, indium, tin, iridium, rhodium and platinum, the molar amount of each kind of metal ion is 10% to 70% of the total molar amount of the metal ions, and the ratio of the total molar amount of the metal ions to the molar amount of the organic ligand is 1:2 to 8. The preparation method has the characteristics of programmable and controllable, the metal types can be adjusted to four or more, and the metal proportion changes less than 5% before and after preparation. The medium / high-entropy metal organic framework material has the characteristics of uniform distribution of metal elements, accurate modulation, replaceable organic ligand, and can accurately control the metal types and proportion in the medium / high-entropy MOFs, and the structure and performance of the obtained sample.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cutting-edge new material technology, and particularly relates to a medium / high-entropy metal organic framework material and a preparation method thereof. BACKGROUND

[0002] Metal organic frameworks (MOFs) are a new type of crystalline porous material with a periodic network structure formed by connecting molecular building units to each other through strong chemical bonds. The main structure is an inorganic-organic hybrid porous framework assembled by metal ions and organic ligands through chemical coordination, wherein the metal ions are the nodes of the framework structure, and the organic ligands are bridging groups connecting the nodes. MOFs materials can be modified by mixing / replacing metal ions and organic ligands, thereby designing and controlling the structure and properties in the framework, so that the materials have the characteristics of structural diversity, rich pore channels, high specific area, and easy functionalization. At the same time, medium / high-entropy MOFs can be formed by various metal ions / organic ligands, which have the characteristics of high stability, high catalytic activity, and multifunctionality in theory, and have a wide range of applications in many fields such as energy storage and conversion, gas adsorption and separation, chemical catalysis, and biological medicine.

[0003] However, the current commonly used preparation methods such as hydrothermal synthesis, stirring synthesis and microwave synthesis are difficult to develop uniform proportion and controllable content of medium / high-entropy MOFs materials. For example, CN118472355A discloses a high-entropy metal organic framework solid-state electrolyte modifier and its preparation method and application. The high-entropy MOFs disclosed in the application are composed of five specific metal elements (Co, Fe, Zn, Mn and Ni), and the high-entropy MOFs are prepared by a conventional liquid phase method. However, the disclosed high-entropy MOFs have a limited adjustable range of metal proportion, which can only be adjusted within 0.8-1.2. CN116655938A discloses a two-dimensional high-entropy metal organic framework material and its preparation method and application. The two-dimensional high-entropy MOFs contain at least three of Ni, Cu, Co, Zn, Mn and Sb, and the ligand contains only at least one. However, the control range of the ligand and the metal is also limited, and the ratio of Fe:Co:Ni:Cu:Zn is specifically defined as 2.92-13.6:0.73-3.4:1:1:1. Moreover, the high-entropy state is not clearly defined. Documents Cryst. Growth Des. 2021, 21, 5349-5359, Microporous Mesoporous Mater. 2024, 375, 1131611 and the like describe an in-situ thermal solvent-free synthesis method, which successfully prepares single and double metal MOFs and adjusts the proportion. However, the method does not consider the competition reaction between different metals and the influence mechanism of metal elements on the entropy of MOFs, especially the influence of multiple metal reaction conditions on the entropy of periodic porous materials. Documents Angew. Chem. Int. Ed. 2019, 58(15), 5018-5022 and the like report a mechanochemical synthesis method, which successfully prepares high-entropy MOFs of five elements. However, the mechanochemical synthesis method cannot accurately control the metal element content before and after preparation, and the method needs to be washed, has low yield, long time consumption and high cost. Therefore, it is a key technical problem in the field to clearly define the entropy of MOFs and develop a preparation method of medium / high-entropy MOFs with accurate adjustable ratio of metal and organic ligand and consistent molar ratio of metal elements before and after preparation. SUMMARY

[0004] Therefore, the present application proposes a medium / high-entropy metal organic framework material and a preparation method thereof. The medium / high-entropy MOFs are clearly defined, and the preparation method can adjust the ratio of metal species in a large range and select the type of ligand. Moreover, the molar ratio of metal ions before and after preparation of the metal organic framework material is consistent, and the medium / high-entropy MOFs are prepared in a green, efficient, low-cost and programmable manner.

[0005] The medium / high-entropy metal organic framework material has a periodic porous structure, is consistent with the topological structure of MOFs formed by a single metal, and the different metal elements in the medium / high-entropy metal organic framework material are uniformly distributed, and the type and content of the metal elements are fully adjustable, and the type of the ligand is selectable.

[0006] The technical scheme of the present application is implemented in the following manner: on one hand, the present application provides a medium / high-entropy metal organic framework material, the configurational entropy ΔS of the medium-entropy metal organic framework material satisfies 1R < ΔS < 1.5R, the configurational entropy ΔS of the high-entropy metal organic framework material satisfies ΔS > 1.5R, R is the gas constant, and is 8.314;

[0007] The metal ions in the medium / high-entropy metal organic framework material are at least four of magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, ruthenium, palladium, silver, cadmium, indium, tin, iridium, rhodium and platinum, and the molar amount of each metal ion is 10% to 70% of the total molar amount of the metal ions, and the ratio of the total molar amount of the metal ions to the molar amount of the organic ligand is 1:2 to 8.

[0008] On the basis of the above technical scheme, preferably, ΔS is calculated by the following formula:

[0009]

[0010] n is the total amount of metal types, n ≥ 4; i is the metal type; X i is the molar fraction of the i-th metal in the metal organic framework; m is the total amount of organic ligand types, m ≥ 1; Y j is the molar fraction of the j-th ligand in the metal organic framework; a ij is the reaction probability constant of the i-th metal and the j-th ligand, which depends on the kinetic constant of different reaction environments; δ is a topological factor, which depends on the topological structure, specifically δ = V × MR, V is the van der Waals volume of the topological structure unit, MR is the node number of the topological structure unit, and δ > 1.

[0011] In the above technical solution, preferably, the organic ligand in the medium / high-entropy metal organic framework is an imidazole-containing compound, selected from one or two of alkylimidazole, halogenated imidazole, phenylimidazole, polyazoles and purines, and specifically selected from one or two of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-chloroimidazole, 2-bromoimidazole, 2-nitroimidazole, 2-mercaptoimidazole, 2-trifluoromethylimidazole, 2-phenylimidazole, 4-methylimidazole, 4-chloroimidazole, 4-bromoimidazole, 4-nitroimidazole, 4,5-dichloroimidazole, 2-imidazole-formaldehyde, 2-imidazole-formic acid, benzimidazole, 2-methylbenzimidazole, 2-aminobenzimidazole, 1H-1,2,3-triazole, 1,2,4-triazole, 3-methyl-1,2,4-triazole, 3,5-dimethyl-1,2,4-triazole, tetrazole, 5-methyltetrazole, 5-aminotetrazole, pentazoles, benzotriazole, 4-azabenzimidazole, 5-azabenzimidazole and 1H-purine.

[0012] In a second aspect, the application provides a preparation method of a medium / high-entropy metal organic framework material, comprising the following steps:

[0013] S1, uniformly mixing a compound containing metal ions with an organic ligand and then grinding to obtain a precursor;

[0014] S2, uniformly spreading the precursor in an alumina crucible and then placing in a tube furnace to perform solid-phase reaction under inert atmosphere or vacuum condition to obtain the medium / high-entropy metal organic framework material.

[0015] In a liquid phase environment, due to the reaction of metal ions with organic ligands under high mobility, the reaction kinetic constants (k) of different metal ions and organic ligands are too different, and although multiple metals and ligands are added, the entropy (ΔS) of the obtained MOFs material is reduced and does not meet the definition of medium / high-entropy material. Therefore, the medium / high-entropy metal organic framework provided by the application is prepared by a solid-phase method, which can balance the reaction kinetics of different metals and organic ligands, and the obtained material has a higher entropy value.

[0016] The preparation method provided by the application makes the metal compound and the organic ligand exist in a molten state, which has the characteristics of low diffusion capacity and high external field energy. In the solid-phase reaction, the metal compound is ionized into metal ions as a solvent at low temperature, and the organic ligand is fully molten as a solution. Different metal ions can fully react with the solvent (organic ligand) around them under the assistance of a thermal field, so that the k ij difference of the metal ions and the organic ligands is small enough, i.e., the k value is small, so that the entropy value of the metal organic framework is high enough.

[0017] On the basis of the above technical scheme, preferably, the total amount of metal compound and the molar amount of organic ligand are in a ratio of 1:2-8, and after weighing, they are ground in a marquis mortar for more than 3 minutes.

[0018] Preferably, the total amount of metal oxide and the molar amount of organic ligand are in a ratio of 1:6, and the grinding time is 5 minutes.

[0019] On the basis of the above technical scheme, preferably, in step S2, during the solid phase reaction, the temperature rising procedure is as follows: the temperature is raised at a rate of 1-10℃ / min until the temperature exceeds the melting point of the metal oxide and reaches more than 140℃, and then the temperature is raised at a rate of 1-10℃ / min until the temperature exceeds the solid phase complexation reaction temperature of the metal organic framework, and the temperature is kept for more than 30 minutes.

[0020] Preferably, the temperature is raised to 140℃ at a rate of 5℃ / min at room temperature, the temperature is kept for 10 minutes, then the temperature is raised to the average of the melting and boiling points of the organic ligand at a rate of 5℃ / min, and the temperature is kept for 60 minutes.

[0021] On the basis of the above technical scheme, preferably, in step S2, the inert gas is one of nitrogen, carbon dioxide, helium, neon, argon, and krypton, the gas flow rate is 50-200cc / min, and the vacuum condition is that the vacuum degree is less than 1×10 -3 Pa.

[0022] On the basis of the above technical scheme, preferably, the metal compound is one or more of metal oxides, metal nitrates, metal chlorides, metal acetates, and metal acetylacetone complexes, and specifically, it can be selected from at least four of the following: magnesium oxide, calcium oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, zirconium oxide, molybdenum oxide, ruthenium oxide, palladium oxide, silver oxide, cadmium oxide, indium oxide, tin oxide, iridium oxide, rhodium oxide, platinum oxide; magnesium nitrate, calcium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, palladium nitrate, silver nitrate, cadmium nitrate, tin nitrate; magnesium chloride, calcium chloride, titanium chloride, vanadium chloride, chromium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, copper chloride, zinc chloride, zirconium chloride, molybdenum chloride, ruthenium chloride, palladium chloride, silver chloride, cadmium chloride, indium chloride, tin chloride, iridium chloride, platinum chloride; magnesium acetate, calcium acetate, manganese acetate, iron acetate, cobalt acetate, nickel acetate, copper acetate, zinc acetate, ruthenium acetate, palladium acetate, silver acetate, cadmium acetate, indium acetate, tin acetate, iridium acetate, platinum acetate; acetylacetone magnesium, acetylacetone titanium, acetylacetone vanadium, acetylacetone chromium, acetylacetone manganese, acetylacetone iron, acetylacetone cobalt, acetylacetone nickel, acetylacetone copper, acetylacetone zinc, acetylacetone zirconium, acetylacetone molybdenum, acetylacetone ruthenium, acetylacetone rhodium, acetylacetone palladium, acetylacetone silver, and acetylacetone cadmium.

[0023] Preferably, the molar ratio of the metal ions before and after the preparation of the metal organic framework material is consistent, and the metal elements are uniformly distributed in the material.

[0024] In a third aspect, the application provides applications of the medium / high-entropy metal organic framework material in the fields of energy storage and conversion, gas adsorption and separation, chemical catalysis, and biomedicine.

[0025] The application of the medium / high-entropy metal organic framework material and the preparation method thereof in gas adsorption has the following beneficial effects compared with the prior art:

[0026] (1) The medium / high-entropy metal organic framework material provided by the application has the characteristics of uniform distribution of metal elements, accurate modulation, and replaceable organic ligands. The different metals in the medium / high-entropy MOFs material change the original structure, and the material obtains more excellent gas adsorption performance.

[0027] (2) The preparation method used by the application can use a plurality of different metals to replace the original single-metal-synthesized MOFs material, accurately control the types and proportions of metals in the medium / high-entropy MOFs, and the structure and performance of the obtained sample.

[0028] (3) In the early stage of preparation of the medium / high-entropy MOFs, the application fully mixes a large number of crystal seeds through physical grinding, and completes the further growth process through heat field assistance. By adjusting the holding time in the mixed metal full solid phase synthesis process, the particle size of the medium / high-entropy MOF crystal can be effectively controlled, so that the particle size of the product powder can be adjusted in the range of nanometers to microns.

[0029] (4) The application uses a mixed metal full solid phase synthesis method to universally synthesize a plurality of medium / high-entropy MOFs materials, realizes the solvent-free, high-yield, and low-cost preparation of the medium / high-entropy MOFs material, has short synthesis time and simple steps, and is suitable for industrial scale production. By adjusting the full solid phase heat synthesis parameters including the types (more than 4) and proportions (10% to 70%) of the organic ligands and metal compounds, the reaction temperature, the holding time, and the atmosphere, the phase and micro / nano structure of the medium / high-entropy MOFs material is designed, so that the types, structure parameters, and performance of the medium / high-entropy MOFs material can be efficiently customized.

[0030] (5) Compared with the medium / high-entropy MOFs material prepared by the existing method, the medium / high-entropy MOFs material prepared by the application has high-temperature thermal stability, can maintain stable structure and performance at 200 to 500 DEG C, and can exist stably for a long time under different synthesis pH values and in air. The medium / high-entropy MOFs material has a wide application prospect in the fields of gas adsorption and separation, catalysis, fluorescence and sensing, chiral structure and function, membrane separation / catalysis and devices, ion conductors, biomedicine, etc. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 Mn prepared in Example 1 0.25 Co 0.25 Ni 0.25 Zn 0.25 -Metal ratio diagram of MOF material before and after preparation;

[0033] Figure 2 Mn prepared in Example 1 0.25 Co 0.25 Ni 0.25 Zn 0.25 XRD patterns of MOF-MOF materials;

[0034] Figure 3 Mn prepared in Example 2 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -Metal ratio diagram of MOF material before and after preparation;

[0035] Figure 4 Mn prepared in Example 2 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -XRD pattern of MOF material;

[0036] Figure 5 Mn prepared in Example 3 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 -Metal ratio diagram of MOF material before and after preparation;

[0037] Figure 6 Mn prepared in Example 3 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu0.1 Zn 0.3 XRD spectrum of the MOF material;

[0038] Figure 7 Mn prepared in Example 1 0.25 Co 0.25 Ni 0.25 Zn 0.25 Morphology of the MOF material taken by scanning electron microscope;

[0039] Figure 8 Mn prepared in Example 1 0.25 Co 0.25 Ni 0.25 Zn 0.25 Carbon dioxide adsorption curve of the MOF material characterized by a full-automatic specific surface area tester. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be apparently and completely described in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0041] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail in combination with specific embodiments below. If the specific conditions of the experiments are not specified in the embodiments, the specific conditions are usually according to the conventional conditions or according to the conditions recommended by the reagent company: the reagents, consumables and the like used in the following embodiments can be obtained through commercial channels, unless otherwise specified.

[0042] Example 1

[0043] The present embodiment provides a Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 The MOF material and the programmable preparation method thereof specifically include the following steps:

[0044] S1, acetylacetone manganese, acetylacetone cobalt, acetylacetone nickel, acetylacetone zinc are mixed in a molar ratio of 1:1:1:1, 2-methylimidazole is added to make the molar ratio of the total amount of metal to organic ligand 1:4, and physical grinding is carried out in a mortar to obtain a fine powder with uniform color, i.e. a precursor is obtained;

[0045] S2, spread the precursor obtained in step S1 evenly in an alumina crucible, then place the alumina crucible in a tube furnace, and perform heating treatment under a protective atmosphere, the specific process conditions are as follows: heat from room temperature to 150℃ at a heating rate of 3℃ / min, then heat from 150℃ to 220℃ at a heating rate of 5℃ / min, keep the temperature for 1.5h, the protective atmosphere is nitrogen, the gas flow rate is 100cc / min, after heating, cool down to room temperature in the furnace to obtain Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF material.

[0046] The Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF prepared in this embodiment has a yield of about 80%, and is still heat stable in water or other solvents in the temperature range of 100-600℃. Figure 1 The Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF material before and after preparation, wherein the metal ratio after preparation is obtained by detection with an inductively coupled plasma spectrometer, which shows that the method has good control over the metal ratio of Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF. Figure 2 The Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF material prepared in this embodiment, and the XRD spectrum of the Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF has no impurities and has a purity of more than 95%. According to calculation, the Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF has an entropy value of 1.22R, which belongs to a medium-entropy material.

[0047] Figure 1 The Mn 0.25 Co 0.25 Ni 0.25 Zn 0.25 -MOF material prepared in Example 1 before and after preparation, wherein the molar ratio after preparation is obtained by analysis after detection with an inductively coupled plasma spectrometer (ICP). As can be seen from the figure, the Mn0.25 Co 0.25 Ni 0.25 Zn 0.25 The consistent molar ratio of metal content in the MOF material before and after preparation demonstrates the programmable nature of the metal element ratio in the programmable preparation method provided by this invention. Compared to the mechanochemical synthesis method described in Angew. Chem. Int. Ed. 2019, 58(15), 5018-5022, the solid-phase synthesis method provided by this invention can better control the metal ratio in MOFs, specifically, the fluctuation of the metal element molar ratio before and after preparation is less than 5% (compared to greater than 10% in the literature).

[0048] Figure 2 Mn prepared in Example 1 0.25 Co 0.25 Ni 0.25 Zn 0.25 The XRD pattern of the MOF material is shown in the figure. 0.25 Co 0.25 Ni 0.25 Zn 0.25 Compared with standard XRD patterns of MOF materials composed of single metals, MOF materials show no other peaks, indicating that Mn... 0.25 Co 0.25 Ni 0.25 Zn 0.25 - Successful preparation of MOFs and maintenance of the periodic porous structure of MOF materials.

[0049] Example 2

[0050] This embodiment provides a Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -MOF materials and their programmable preparation methods, specifically including the following steps:

[0051] S1. Mix manganese acetylacetone, iron acetylacetone, cobalt acetylacetone, nickel acetylacetone, copper acetylacetone, and zinc acetylacetone in a molar ratio of 2:1:2:2:1:2, then add 2-methylimidazole to make the molar ratio of the mixed metal to the organic ligand 1:6, and physically grind it in a mortar into a fine powder with uniform color to obtain the precursor.

[0052] S2, the precursor obtained in step S1 is evenly spread in an alumina crucible, and the alumina crucible is placed in a tube furnace, and a reducing atmosphere is introduced for pyrolysis treatment, and the specific process conditions are as follows: the temperature is increased to 150 DEG C at a rate of 3 DEG C / min at room temperature, and the temperature is kept for 1 h, then the temperature is increased to 220 DEG C at a rate of 5 DEG C / min, and the temperature is kept for 2 h, the protective atmosphere is nitrogen, the gas flow rate is 100 cc / min, after heating, the furnace is cooled to room temperature to obtain Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -MOF material.

[0053] It is tested that the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -MOF prepared in the embodiment has a purity of more than 95%, a yield of about 85%, and is still heat stable in water or other solvents in the temperature range of 100-600 DEG C. Figure 3 The Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -MOF material before and after preparation, wherein the metal ratio after preparation is detected by an inductively coupled plasma emission spectrometer, which shows that the method can adjust the metal type in the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -MOF metal ratio has good control. Figure 4 The XRD spectrum of the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -MOF material prepared. It is calculated that the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 -MOF has an entropy value of 2.27R, which belongs to high-entropy materials.

[0054] By comparison, the embodiment 1 and the present embodiment fully illustrate that the method can adjust the metal type in the medium / high-entropy metal organic framework material.

[0055] Figure 3 Mn prepared in Example 2 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 The metal ratio chart of the MOF material before and after preparation, wherein the molar ratio after preparation is analyzed by ICP test. As can be seen from the figure, the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 The molar ratio of the metal content of the MOF material before and after preparation is consistent, which shows that the programmable preparation method provided by the present application has programmable characteristics for the types and proportions of metal elements. Compared with the mechanical chemical synthesis method described in the literature Angew. Chem. Int. Ed. 2019, 58(15), 5018-5022, the solid-phase synthesis method provided by the present application can better control the metal ratio in the MOF, and specifically, the fluctuation of the molar ratio of metal elements before and after preparation is less than 4% (more than 10% in the literature).

[0056] Figure 4 Mn prepared in Example 2 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 The XRD spectrum of the MOF material, as can be seen from the figure, the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 Compared with the standard XRD of the MOF material composed of a single metal, there is no other peak, which shows that the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 The MOF is successfully prepared and the periodic porous structure of the MOF material is maintained.

[0057] Comparative Example 1 and in combination with Figure 1 , 2 , 3, 4, it can be seen that the programmable preparation method can control the types of metal elements, and the content of each type of metal element remains substantially unchanged before and after preparation.

[0058] Example 3

[0059] The embodiment provides a Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 -MOF material and a programmable preparation method thereof, and specifically comprises the following steps:

[0060] S1, acetylacetone manganese, acetylacetone iron, acetylacetone cobalt, acetylacetone nickel, acetylacetone copper and acetylacetone zinc are mixed in a molar ratio of 1:1:3:1:1:3, 2-methylimidazole is added to make the molar ratio of mixed metal and organic ligand 1:6, and physical grinding is performed in a mortar to obtain a fine powder with uniform color, that is, a precursor is obtained;

[0061] S2, the precursor obtained in step S1 is uniformly spread in an alumina crucible, the alumina crucible is placed in a tube furnace, and pyrolysis treatment is performed in a reducing atmosphere, and the specific process conditions are as follows: the temperature is increased to 150 DEG C at a temperature increasing rate of 3 DEG C / min at room temperature, and the temperature is kept for 1 h, then the temperature is increased to 220 DEG C at a temperature increasing rate of 5 DEG C / min, and the temperature is kept for 2 h, the protective atmosphere is nitrogen, the gas flow rate is 100 cc / min, and after heating is completed, the furnace is cooled to room temperature to obtain a Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 -MOF material.

[0062] It is tested that the Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 -MOF prepared in the embodiment has a purity of more than 95%, a yield of about 80%, and is still heat stable in water or other solvents in a temperature range of 100-600 DEG C. Figure 5 A metal ratio chart of the Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 -MOF material obtained in the embodiment before and after preparation, wherein the metal ratio after preparation is obtained by detection of an inductively coupled plasma emission spectrometer, and it is shown that the method is suitable for Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3The proportion of the metal in the MOF is well controlled. Figure 6 The Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 The XRD spectrum of the MOF material. It is calculated that the Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 The entropy of the MOF is 2.32R, belonging to a high-entropy material.

[0063] By comparison, example 2 and the present example fully illustrate that the method can adjust the proportion of metal in the medium / high-entropy metal organic framework material.

[0064] Figure 5 The Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 The metal proportion diagram of the MOF material before and after preparation, wherein the molar proportion after preparation is obtained by ICP test and analysis. As can be seen from the figure, the Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 The molar proportion of the metal content of the MOF material before and after preparation is consistent, which illustrates that the programmable preparation method provided by the present application can accurately adjust the proportion of metal elements. Compared with the Mn 0.2 Fe 0.1 Co 0.2 Ni 0.2 Cu 0.1 Zn 0.2 MOF, the present method can accurately and programmably prepare the molar ratio of metal in the MOF.

[0065] Figure 6 The Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 The XRD spectrum of the MOF material, as can be seen from the figure, the Mn 0.1 Fe 0.1 Co 0.3 Ni0.1 Cu 0.1 Zn 0.3 -MOF material has no other peaks compared with standard XRD of MOF material composed of single metal, indicating that Mn 0.1 Fe 0.1 Co 0.3 Ni 0.1 Cu 0.1 Zn 0.3 -MOF is successfully prepared and keeps the periodic porous structure of MOFs material.

[0066] Compared with Comparative Example 2 and combined with Figure 3 , 4 , 5, 6, it can be seen that the programmable preparation method can control the content of metal elements, and the content of each metal element remains substantially unchanged before and after preparation.

[0067] Example 4

[0068] This example provides a Mn 0.1 Co 0.1 Cu 0.1 Zn 0.7 -MOF material and a programmable preparation method thereof, specifically comprising the following steps:

[0069] S1, manganese acetate, cobalt acetate, copper acetate and zinc acetate are mixed in a molar ratio of 1:1:1:7, then benzimidazole is added to make the molar ratio of mixed metal to organic ligand 1:8, and physical grinding is carried out in a mortar to obtain a fine powder with uniform color, i.e. a precursor is obtained;

[0070] S2, the precursor obtained in step S1 is uniformly spread in an alumina crucible, and then the alumina crucible is placed in a tube furnace, and a reducing atmosphere is introduced for pyrolysis treatment, and the specific process conditions are as follows: the temperature is raised to 155℃ at a heating rate of 5℃ / min at room temperature, and then the temperature is raised to 289℃ at a heating rate of 8℃ / min, and the temperature is kept for 2h, the protective atmosphere is nitrogen, the gas flow rate is 180cc / min, and after heating, the furnace is cooled to room temperature to obtain a Mn 0.25 Co 0.25 Cu 0.25 Zn 0.25 -MOF material.

[0071] Tests show that the yield of Mn 0.1 Co 0.1 Cu 0.1 Zn 0.7 -MOF prepared in this example is about 80%, and it remains thermally stable in water or other solvents in the temperature range of 100-400℃. The Mn 0.1 Co 0.1Cu 0.1 Zn 0.7 The metal ratio of the MOF material before and after preparation is consistent, which shows that the method has good control on the Mn 0.1 Co 0.1 Cu 0.1 Zn 0.7 The metal ratio of the MOF material before and after preparation is consistent, which shows that the method has good control on the Mn 0.1 Co 0.1 Cu 0.1 Zn 0.7 The metal ratio of the MOF material before and after preparation is consistent, which shows that the method has good control on the Mn 0.1 Co 0.1 Cu 0.1 Zn 0.7 The entropy value of the MOF is 1.04R, which belongs to a medium entropy material.

[0072] Example 5

[0073] The embodiment provides an Fe 0.25 Co 0.25 Ni 0.25 Zn 0.25 The embodiment provides an Fe

[0074] S1, acetylacetone iron, acetylacetone cobalt, acetylacetone nickel, acetylacetone zinc are mixed in a molar ratio of 1:1:1:1, 5-methyltetrazole is added to make the molar ratio of mixed metal and organic ligand 1:2, and physical grinding is performed in a mortar to obtain a fine powder with uniform color, that is, a precursor is obtained;

[0075] S2, the precursor obtained in step S1 is uniformly spread in an alumina crucible, the alumina crucible is placed in a tube furnace, and pyrolysis treatment is performed in a reducing atmosphere, and the specific process conditions are as follows: the temperature is increased to 170 DEG C at a temperature increasing rate of 5 DEG C / min at room temperature, and the temperature is kept for 1 h, then the temperature is increased to 200 DEG C at a temperature increasing rate of 10 DEG C / min, and the temperature is kept for 2 h, the protective atmosphere is carbon dioxide, the gas flow rate is 100 cc / min, and after heating is completed, the furnace is cooled to room temperature to obtain an Fe 0.25 Co 0.25 Ni 0.25 Zn 0.25 MOF material.

[0076] The test shows that the yield of the Fe 0.25 Co 0.25 Ni 0.25 Zn 0.25 MOF prepared in the embodiment is about 70%, and the Fe 0.25 Co 0.25Ni 0.25 Zn 0.25 The metal ratio of the -MOF material is consistent before and after preparation, showing that the method has good control over the metal ratio of the -MOF material. 0.25 Co 0.25 Ni 0.25 Zn 0.25 The metal ratio of the -MOF material is consistent before and after preparation, showing that the method has good control over the metal ratio of the -MOF material. 0.25 Co 0.25 Ni 0.25 Zn 0.25 The -MOF material is free of impurities and has a purity of more than 95%. According to calculation, the Mn 0.25 Co 0.25 Cu 0.25 Zn 0.25 The entropy value of the -MOF is 1.22R, belonging to a medium-entropy material.

[0077] Example 6

[0078] The present embodiment provides a kind of Mn 0.1 Fe 0.1 Co 0.2 Ni 0.1 Cu 0.1 Zn 0.3 Cd 0.1 -MOF material and its programmable preparation method, specifically comprising the following steps:

[0079] S1, manganese chloride, iron chloride, cobalt chloride, nickel chloride, copper chloride, zinc chloride, cadmium chloride are mixed according to the molar ratio of 1:1:2:1:1:3:1, then 2-chloroimidazole is added to make the molar ratio of mixed metal and organic ligand 1:6, and physical grinding is carried out in mortar to form fine powder with uniform color, to obtain the precursor;

[0080] S2, the precursor obtained in step S1 is uniformly spread in alumina crucible, then the alumina crucible is placed in tube furnace, and reducing atmosphere is introduced for pyrolysis treatment, and the specific process conditions are as follows: the temperature is increased to 160 DEG C at a heating rate of 10 DEG C / min at room temperature, and then the temperature is increased to 221 DEG C at a heating rate of 5 DEG C / min, and the temperature is kept for 2h, the protective atmosphere is neon, the gas flow rate is 80cc / min, and the heating is stopped after the furnace is cooled to room temperature to obtain Mn 0.1 Fe 0.1 Co 0.2 Ni 0.1 Cu 0.1 Zn 0.3 Cd 0.1 -MOF material.

[0081] After testing, the Mn 0.1 Fe 0.1 Co 0.2Ni 0.1 Cu 0.1 Zn 0.3 Cd 0.1 -MOF yield is about 80%, and in the temperature range of 100-250℃, water or other solvents can still maintain thermal stability. The Mn 0.1 Fe 0.1 Co 0.2 Ni 0.1 Cu 0.1 Zn 0.3 Cd 0.1 -MOF material before and after preparation of the metal ratio is consistent, showing that the method for Mn 0.1 Fe 0.1 Co 0.2 Ni 0. 1Cu 0.1 Zn 0.3 Cd 0.1 -MOF metal ratio has good control. The material obtained is Mn 0.1 Fe 0.1 Co 0.2 Ni 0.1 Cu 0.1 Zn 0.3 Cd 0.1 -MOF, no impurities, purity of more than 95%. By calculation, Mn 0.1 Fe 0.1 Co 0.2 Ni 0.1 Cu 0.1 Zn 0.3 Cd 0.1 -MOF entropy value is 2.65R, which belongs to high-entropy material.

[0082] Example 7

[0083] This example provides a Co 0.4 Ni 0.1 Cu 0.2 Zn 0.3 -MOF material and its programmable preparation method, specifically comprising the following steps:

[0084] S1, cobalt acetylacetone, nickel acetylacetone, copper acetylacetone, zinc acetylacetone are mixed in a molar ratio of 4:1:2:3, 2-methyl imidazole and benzimidazole are mixed in a ratio of 1:1, then the mixed metal and mixed organic ligand are mixed in a molar ratio of 1:6, and are physically ground in a mortar to a fine powder with uniform color, to obtain a precursor;

[0085] S2, the precursor obtained in step S1 is evenly spread in an alumina crucible, and the alumina crucible is placed in a tube furnace, and a reducing atmosphere is introduced for pyrolysis treatment, and the specific process conditions are as follows: the temperature is increased to 145 DEG C at a heating rate of 3 DEG C / min at room temperature, and the temperature is kept for 1 h, then the temperature is increased to 255 DEG C at a heating rate of 5 DEG C / min, and the temperature is kept for 2 h, the protective atmosphere is argon, the gas flow rate is 150 cc / min, and after heating, the furnace is cooled to room temperature to obtain Co 0.4 Ni 0.1 Cu 0.2 Zn 0.3 -MOF material.

[0086] It is tested that the Co 0.4 Ni 0.1 Cu 0.2 Zn 0.3 -MOF prepared in the embodiment has a yield of about 80%, and is still heat stable in water or other solvents in the temperature range of 100-250 DEG C. The Co 0.4 Ni 0.1 Cu 0.2 Zn 0.3 -MOF material has the same metal ratio before and after preparation, and has a grid structure of mixed ligands, which shows that the method has good control on the metal ratio of Co 0.4 Ni 0.1 Cu 0.2 Zn 0.3 -MOF. The obtained material is Co 0.4 Ni 0.1 Cu 0.2 Zn 0.3 -MOF, and the purity is more than 95%. It is calculated that the Co 0.4 Ni 0.1 Cu 0.2 Zn 0.3 -MOF has an entropy value of 2.08R, which belongs to a high-entropy material.

[0087] Embodiment 8

[0088] The embodiment provides a Zn 0.5 Ru 0.1 Rh 0.1 Pb 0.1 Ag 0.1 Pt 0.1 -MOF material and a programmable preparation method thereof, and specifically includes the following steps:

[0089] S1, zinc acetylacetone, ruthenium acetylacetone (III), rhodium acetylacetone (III), palladium acetylacetone (II), silver acetylacetone (I), and platinum acetylacetone (II) are mixed in a molar ratio of 5:1:1:1:1:1, and then benzotriazole is added to make the molar ratio of the mixed metal to the organic ligand 1:6. The mixture is then physically ground in a mortar into a fine powder with uniform color to obtain the precursor.

[0090] S2. The precursor obtained in step S1 is evenly spread in an alumina crucible, and then the alumina crucible is placed in a tube furnace. A reducing atmosphere is introduced for pyrolysis treatment. The specific process conditions are as follows: the temperature is increased to 150°C at a heating rate of 1°C / min at room temperature and held for 1 hour, then increased to 164°C at a heating rate of 1°C / min and held for 2 hours. The protective atmosphere is krypton with a gas flow rate of 200 cc / min. After heating, the furnace is cooled to room temperature to obtain Zn. 0.5 Ru 0.1 Rh 0.1 Pb 0.1 Ag 0.1 Pt 0.1 -MOF materials.

[0091] The Zn prepared in this embodiment was tested and found to be effective. 0.5 Ru 0.1 Rh 0.1 Pb 0.1 Ag 0.1 Pt 0.1 The yield of -MOF is approximately 80%, and it remains thermally stable in water or other solvents within a temperature range of 100–250 °C. The Zn obtained in this example... 0.5 Ru 0.1 Rh 0.1 Pb 0.1 Ag 0.1 Pt 0.1 The MOF material exhibits consistent metal ratios before and after preparation and possesses a mixed ligand network structure, demonstrating the effectiveness of this method for Zn. 0.5 Ru 0.1 Rh 0.1 Pb 0.1 Ag 0.1 Pt 0.1 The MOF metal ratio can be well controlled. The resulting material is Zn. 0.5 Ru 0.1 Rh 0.1 Pb 0.1 Ag 0.1 Pt 0.1 -MOF, free of impurities, with a purity exceeding 90%. Calculations show that Zn... 0.5 Ru 0.1 Rh 0.1 Pb 0.1 Ag0.1 Pt 0.1 -MOF has an entropy value of 2.39R, which is considered a high-entropy material.

[0092] Applications of medium / high entropy metal-organic frameworks in carbon dioxide adsorption:

[0093] Figure 7 Mn prepared in Example 1 0.25 Co 0.25 Ni 0.25 Zn 0.25 - A morphological image of the MOF material taken using a scanning electron microscope. As can be seen from the image, the primary particles exhibit dodecahedrons (approximately 1–3 μm in diameter), while the secondary particles exhibit irregular polyhedra (approximately 200–500 nm in diameter). The secondary particles are a small number of initially grown unit cells dispersed on and around the surface of the primary particles.

[0094] The dodecahedral morphology of primary particles provides a high surface area, increasing the contact area with gas molecules and facilitating their diffusion and contact. These particles, with a moderate size range (1–3 μm), ensure good dispersibility in practical applications, preventing clogging and increasing specific surface area, thus promoting gas adsorption. Smaller particle sizes (200–500 nm) offer even higher specific surface area and more porous structures, further enhancing the material's ability to contact gases. This hierarchical structure (composed of primary dodecahedral particles and secondary irregular polyhedral particles) facilitates the diffusion of gas molecules through micropores and mesopores, enabling them to quickly reach internal adsorption sites.

[0095] Figure 8 Mn prepared in Example 1 0.25 Co 0.25 Ni 0.25 Zn 0.25 The carbon dioxide adsorption curves of MOF materials characterized by a fully automated specific surface area tester show superior carbon dioxide adsorption performance compared with low-entropy (single metal) MOF materials reported in Sep. Purif. Technol. 2025, 358(B), 130389 and Molecules, 2023, 28(20), 7056, indicating their potential application in industrial and automotive waste gas adsorption fields.

[0096] Comparative Example 1

[0097] This embodiment provides a Fe 0.05 Co 0.05 Ni 0.05 Cu 0.05 Zn 0.8 -MOF materials and their programmable preparation methods, specifically including the following steps:

[0098] S1, ferrous acetate, cobalt acetate, nickel acetate, copper acetylacetonate, zinc oxide are mixed in a molar ratio of 1:1:1:1:16, 2-methylimidazole is added to make the molar ratio of mixed metal to organic ligand 1:4, and then physically ground in a mortar to a fine powder with uniform color, to obtain the precursor;

[0099] S2, the precursor obtained in step S1 is uniformly spread in an alumina crucible, the alumina crucible is placed in a tube furnace, and a reducing atmosphere is introduced for pyrolysis treatment, the specific process conditions are as follows: the temperature is raised to 100℃ at a rate of 1℃ / min, and then the temperature is raised to 220℃ at a rate of 5℃ / min, and the temperature is kept for 1h, the protective atmosphere is krypton, the gas flow rate is 100cc / min, and after heating, the furnace is cooled to room temperature to obtain Fe 0.05 Co 0.05 Ni 0.05 Cu 0.05 Zn 0.8 -MOF material.

[0100] It is tested that the Fe 0.05 Co 0.05 Ni 0.05 Cu 0.05 Zn 0.8 -MOF prepared in this embodiment has a yield of about 90%, and is still heat stable in water or other solvents in the temperature range of 100-500℃. The Fe 0.05 Co 0.05 Ni 0.05 Cu 0.05 Zn 0.8 -MOF material obtained in this example has the same metal ratio before and after preparation, and has a grid structure of mixed ligands, which shows that the method has good control on the metal ratio of Fe 0.05 Co 0.05 Ni 0.05 Cu 0.05 Zn 0.8 -MOF. The obtained material is Fe 0.05 Co 0.05 Ni 0.05 Cu 0.05 Zn 0.8 -MOF, which is free of impurities and has a purity of more than 90%. It is calculated that the entropy of Fe 0.05 Co 0.05 Ni 0.05 Cu 0.05 Zn 0.8 -MOF is 0.91R, which belongs to a low-entropy material. The comparative example illustrates the controllable preparation of other low-entropy materials of the same type by the programmable preparation method.

[0101] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a medium / high-entropy metal-organic framework material, characterized in that, The method comprises the following steps: S1, grinding a compound containing metal ions and an organic ligand after mixing them uniformly to obtain a precursor; The metal ions are at least four of magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, ruthenium, palladium, silver, cadmium, indium, tin, iridium, rhodium and platinum, the molar amount of each metal ion is 10% to 70% of the total molar amount of the metal ions, and the ratio of the total molar amount of the metal ions to the molar amount of the organic ligand is 1:2 to 8; The organic ligand is selected from one or two of alkyl imidazole, halogenated imidazole, phenyl imidazole, polyazoles and purines; S2, uniformly spreading the precursor in an alumina crucible, and then placing it in a tube furnace to heat and perform solid-phase reaction under inert atmosphere or vacuum condition to obtain a medium / high-entropy metal organic framework material; During the solid-phase reaction, the temperature rising procedure is as follows: rising at a temperature rising rate of 1-10 ℃ / min until the temperature exceeds the melting point of the metal compound, reaches above 140 ℃, and is kept for more than 30 min, and then rising at a temperature rising rate of 1-10 ℃ / min until the temperature exceeds the solid-phase complexation reaction temperature of the metal organic framework, and is kept for more than 30 min.

2. The method for preparing a medium / high entropy metal-organic framework material as described in claim 1, characterized in that, The configuration entropy ΔS of the medium-entropy metal organic framework material satisfies 1R<ΔS<1.5R, and the configuration entropy ΔS of the high-entropy metal organic framework material satisfies ΔS>1.5R, R being the gas constant.

3. The method for preparing a medium / high entropy metal-organic framework material as described in claim 2, characterized in that, The ΔS is calculated by the following formula: ； n This represents the total number of metal types. n ≥4; i Types of metals; X i denoted as the mole fraction of the i-th metal in the metal-organic framework; m This represents the total number of organic ligand types. m ≥1; Y j For the first metal-organic framework j The mole fraction of each ligand; a ij for i Metal and the first j The reaction probability constant of a ligand depends on the kinetic constants of different reaction environments; The metal compound is one or more of metal oxides, metal nitrates, metal chlorides, metal acetates and metal acetylacetone complexes. It is a topological factor, which depends on the topological structure. The molar ratio of the metal ions changes by less than 5% before and after the preparation of the metal organic framework material, and the metal elements are uniformly distributed in the material. =V×MR, where V is the van der Waals volume of the topological element, and MR is the number of nodes in the topological element. ​ >1.

4. The method for preparing a medium / high entropy metal-organic framework material as described in claim 1, characterized in that, In step S2, the inert gas is one of nitrogen, carbon dioxide, helium, neon, argon, krypton, and the gas flow rate is 50-200 cc / min; the vacuum condition is a vacuum degree less than 1x10 -3 Pa.

5. The method for preparing a medium / high entropy metal-organic framework material as described in claim 1, characterized in that, ​ 6. The method for preparing a medium / high entropy metal-organic framework material as described in claim 1, characterized in that, ​

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