Composite hydrogen storage material and preparation method thereof

Abstract

The invention relates to a composite hydrogen storage material and a preparation method thereof, belongs to the technical field of composite hydrogen storage materials, and discloses a composite hydrogen storage material which comprises the following raw materials in parts by weight: 2-10 parts of graphene, 3-8 parts of nanoparticles and 5-10 parts of MOFs particles. According to the composite hydrogen storage material and the preparation method thereof, by accurately controlling the weight part ratio of the graphene, the nano-particles and the MOFs particles, the dosage of the additive can be remarkably reduced, meanwhile, the hydrogen storage performance is maintained and even improved, and due to the optimized ratio, the composite material has excellent performance in the aspects of hydrogen storage capacity, hydrogen absorption and desorption rate and the like, and does not need to excessively depend on the additive; the graphene provides excellent electrical conductivity and mechanical strength, the nano-particles increase hydrogen storage sites, the MOFs particles have high specific surface area and rich pore structures, adsorption and storage of hydrogen are facilitated, and through reasonable proportioning, the components can achieve a synergistic effect, and efficient hydrogen storage is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of composite hydrogen storage materials, in particular to a composite hydrogen storage material and a preparation method thereof. Background Art

[0002] Composite hydrogen storage materials refer to new materials with excellent hydrogen storage performance formed by combining two or more hydrogen storage materials through a specific process. These materials can be classified according to their composition and hydrogen storage mechanism, such as alloy-based composite hydrogen storage materials, inorganic / organic-based composite hydrogen storage materials, etc.

[0003] Publication No. CN119551631A discloses a composite hydrogen storage material and its preparation method and application, belonging to the technical field of hydrogen storage materials and their preparation. The present invention solves the problems of excessive additive dosage and poor low-temperature kinetics in the existing aluminum hydride composite hydrogen storage system. The present invention uses rare earth nitride as an additive, utilizes the multivalent state characteristics of rare earth elements as active centers, and utilizes the attraction of nitrogen elements to negatively charged hydrogen to accelerate the dissociation and transmission of hydrogen. At the same time, since nitrogen elements have rich valence states, rare earth elements can use nitrogen active sites as a bridge to transmit electrons with aluminum hydride, achieving a synergistic effect between the two. The electron donating effect of nitrogen elements enhances the affinity between rare earth elements and hydrogen elements, reduces the dehydrogenation temperature of aluminum hydride materials, and also improves the dehydrogenation kinetics of aluminum hydride materials in the low temperature zone. In addition, the preparation process of the composite hydrogen storage material provided by the present invention is simple and mature, and the raw materials are cheap and easy to obtain, which is convenient for large-scale industrial production.

[0004] The above patent improves the shortcomings of the existing aluminum hydride composite hydrogen storage material, namely, excessive dosage of additives and poor low-temperature kinetics. The present application provides another implementation scheme for the problems raised in the above patent. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a composite hydrogen storage material and a preparation method thereof, which has the advantages of small amount of additives and strong low-temperature kinetics, and solves the problem of excessive amount of additives and poor low-temperature kinetics of aluminum hydride composite hydrogen storage materials in the prior art.

[0006] In order to achieve the above-mentioned purpose of small amount of additives and strong low-temperature kinetics, the present invention provides the following technical solution: a composite hydrogen storage material, comprising the following raw materials in the following weight proportions: 2-10 parts of graphene, 3-8 parts of nanoparticles, and 5-10 parts of MOFs particles.

[0007] Furthermore, the raw materials are included in the following weight proportions: 5 parts of graphene, 4 parts of nanoparticles, and 6 parts of MOFs particles.

[0008] Furthermore, the raw materials are included in the following weight proportions: 6 parts of graphene, 5.5 parts of nanoparticles, and 7 parts of MOFs particles.

[0009] Furthermore, the raw materials are included in the following weight proportions: 8 parts of graphene, 7 parts of nanoparticles, and 9 parts of MOFs particles.

[0010] Furthermore, the graphene is a graphene nanosheet, and the size of the graphene is between 1-3 microns.

[0011] Furthermore, the size of the nanoparticles is between 5 and 20 nanometers.

[0012] Furthermore, the size of the MOFs particles is between 20-50 nanometers, and the surface pore size of the MOFs particles is between 0.3-2 nanometers.

[0013] Another technical problem to be solved by the present invention is to provide a method for preparing a composite hydrogen storage material, comprising the following steps:

[0014] 1) Raw material mixing: Dissolve the precursors of graphene, nanoparticles and MOFs in an appropriate solvent to form a uniform mixed solution, and use ultrasonic treatment or mechanical stirring to uniformly mix the graphene, nanoparticles and MOFs to ensure that each component is fully dispersed;

[0015] 2) Solution synthesis: The mixed solution is transferred to a reaction vessel, and the synthesis is carried out by a hydrothermal method or a solvothermal method, and an appropriate temperature and reaction time are set. After the reaction is completed, the reaction system is cooled, and the solid product is separated by centrifugation or filtration;

[0016] 3) Pretreatment of the solidified material: washing the solid product with an appropriate solvent to remove unreacted precursors and impurities, drying the washed product in a vacuum drying oven or an oven to remove residual solvent, and obtaining a composite material after the pretreatment is completed;

[0017] 4) Composite material analysis: Use X-ray diffraction to analyze the crystal structure of the composite material; use scanning electron microscopy and transmission electron microscopy to observe the morphology and microstructure of the composite material;

[0018] 5) Composite material evaluation: The specific surface area and pore structure of the composite material were determined by nitrogen adsorption-desorption experiments, and the hydrogen adsorption capacity of the composite material was evaluated, including the adsorption amount and release rate;

[0019] 6) Composite material adjustment: Based on the characterization results and hydrogen storage performance, the material applicability is evaluated and the synthesis conditions are adjusted according to the test results to optimize the material performance.

[0020] Furthermore, the reaction temperature in 2) is 100-200° C., and the reaction time is 12-36 hours.

[0021] Furthermore, the synthesis conditions in 6) include temperature, time and precursor ratio.

[0022] Compared with the prior art, the present invention provides a composite hydrogen storage material and a preparation method thereof, which has the following beneficial effects:

[0023] 1. The composite hydrogen storage material and its preparation method can significantly reduce the amount of additives used while maintaining or even improving the hydrogen storage performance by precisely controlling the weight ratio of graphene, nanoparticles and MOFs particles. This optimized ratio enables the composite material to perform well in terms of hydrogen storage capacity, hydrogen absorption and desorption rate, etc., without relying too much on additives. Graphene provides excellent conductivity and mechanical strength, nanoparticles increase hydrogen storage sites, and MOFs particles have a high specific surface area and rich pore structure, which are conducive to the adsorption and storage of hydrogen. Through reasonable ratios, these components can work synergistically to achieve efficient hydrogen storage.

[0024] 2. The composite hydrogen storage material and its preparation method optimize the size of MOFs particles and the surface pore size so that the composite material has a more suitable pore structure and specific surface area, which is beneficial to the adsorption and desorption of hydrogen at low temperatures. Ultrasonic treatment or mechanical stirring are used to ensure that graphene, nanoparticles and MOFs particles are evenly dispersed in the composite material, thereby enhancing the interface interaction between the components and helping to improve the overall stability and low-temperature kinetic properties of the composite material. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] A composite hydrogen storage material comprises the following raw materials in the following weight proportions: 5 parts of graphene, 4 parts of nanoparticles, and 6 parts of MOFs particles.

[0028] Specifically, the graphene is a graphene nanosheet, and the size of the graphene is between 1-3 microns.

[0029] Specifically, the size of the nanoparticles is between 5-20 nanometers.

[0030] Specifically, the size of MOFs particles is between 20-50 nanometers, and the surface pore size of MOFs particles is between 0.3-2 nanometers.

[0031] A method for preparing a composite hydrogen storage material comprises the following steps:

[0032] 1) Raw material mixing: Dissolve the precursors of graphene, nanoparticles and MOFs in an appropriate solvent to form a uniform mixed solution, and use ultrasonic treatment or mechanical stirring to uniformly mix the graphene, nanoparticles and MOFs to ensure that each component is fully dispersed;

[0033] 2) Solution synthesis: The mixed solution is transferred to a reaction vessel, and the synthesis is carried out by a hydrothermal method or a solvothermal method, and an appropriate temperature and reaction time are set. After the reaction is completed, the reaction system is cooled, and the solid product is separated by centrifugation or filtration;

[0034] 3) Pretreatment of the solidified material: washing the solid product with an appropriate solvent to remove unreacted precursors and impurities, drying the washed product in a vacuum drying oven or an oven to remove residual solvent, and obtaining a composite material after the pretreatment is completed;

[0035] 4) Composite material analysis: Use X-ray diffraction to analyze the crystal structure of the composite material; use scanning electron microscopy and transmission electron microscopy to observe the morphology and microstructure of the composite material;

[0036] 5) Composite material evaluation: The specific surface area and pore structure of the composite material were determined by nitrogen adsorption-desorption experiments, and the hydrogen adsorption capacity of the composite material was evaluated, including the adsorption amount and release rate;

[0037] 6) Composite material adjustment: Based on the characterization results and hydrogen storage performance, the material applicability is evaluated and the synthesis conditions are adjusted according to the test results to optimize the material performance.

[0038] 2) The reaction temperature is 100-200°C and the reaction time is 12-36H.

[0039] The synthesis conditions in 6) include temperature, time and precursor ratio.

[0040] Embodiment 2:

[0041] A composite hydrogen storage material comprises the following raw materials in the following weight proportions: 6 parts of graphene, 5.5 parts of nanoparticles, and 7 parts of MOFs particles.

[0042] Specifically, the graphene is a graphene nanosheet, and the size of the graphene is between 1-3 microns.

[0043] Specifically, the size of the nanoparticles is between 5-20 nanometers.

[0044] Specifically, the size of MOFs particles is between 20-50 nanometers, and the surface pore size of MOFs particles is between 0.3-2 nanometers.

[0045] A method for preparing a composite hydrogen storage material comprises the following steps:

[0046] 1) Raw material mixing: Dissolve the precursors of graphene, nanoparticles and MOFs in an appropriate solvent to form a uniform mixed solution, and use ultrasonic treatment or mechanical stirring to uniformly mix the graphene, nanoparticles and MOFs to ensure that each component is fully dispersed;

[0047] 2) Solution synthesis: The mixed solution is transferred to a reaction vessel, and the synthesis is carried out by a hydrothermal method or a solvothermal method, and an appropriate temperature and reaction time are set. After the reaction is completed, the reaction system is cooled, and the solid product is separated by centrifugation or filtration;

[0048] 3) Pretreatment of the solidified material: washing the solid product with an appropriate solvent to remove unreacted precursors and impurities, drying the washed product in a vacuum drying oven or an oven to remove residual solvent, and obtaining a composite material after the pretreatment is completed;

[0049] 4) Composite material analysis: Use X-ray diffraction to analyze the crystal structure of the composite material; use scanning electron microscopy and transmission electron microscopy to observe the morphology and microstructure of the composite material;

[0050] 5) Composite material evaluation: The specific surface area and pore structure of the composite material were determined by nitrogen adsorption-desorption experiments, and the hydrogen adsorption capacity of the composite material was evaluated, including the adsorption amount and release rate;

[0051] 6) Composite material adjustment: Based on the characterization results and hydrogen storage performance, the material applicability is evaluated and the synthesis conditions are adjusted according to the test results to optimize the material performance.

[0052] 2) The reaction temperature is 100-200°C and the reaction time is 12-36H.

[0053] The synthesis conditions in 6) include temperature, time and precursor ratio.

[0054] Embodiment three:

[0055] A composite hydrogen storage material comprises the following raw materials in the following weight proportions: 8 parts of graphene, 7 parts of nanoparticles, and 9 parts of MOFs particles.

[0056] Specifically, the graphene is a graphene nanosheet, and the size of the graphene is between 1-3 microns.

[0057] Specifically, the size of the nanoparticles is between 5-20 nanometers.

[0058] Specifically, the size of MOFs particles is between 20-50 nanometers, and the surface pore size of MOFs particles is between 0.3-2 nanometers.

[0059] A method for preparing a composite hydrogen storage material comprises the following steps:

[0060] 1) Raw material mixing: Dissolve the precursors of graphene, nanoparticles and MOFs in an appropriate solvent to form a uniform mixed solution, and use ultrasonic treatment or mechanical stirring to uniformly mix the graphene, nanoparticles and MOFs to ensure that each component is fully dispersed;

[0061] 2) Solution synthesis: The mixed solution is transferred to a reaction vessel, and the synthesis is carried out by a hydrothermal method or a solvothermal method, and an appropriate temperature and reaction time are set. After the reaction is completed, the reaction system is cooled, and the solid product is separated by centrifugation or filtration;

[0062] 3) Pretreatment of the solidified material: washing the solid product with an appropriate solvent to remove unreacted precursors and impurities, drying the washed product in a vacuum drying oven or an oven to remove residual solvent, and obtaining a composite material after the pretreatment is completed;

[0063] 4) Composite material analysis: Use X-ray diffraction to analyze the crystal structure of the composite material; use scanning electron microscopy and transmission electron microscopy to observe the morphology and microstructure of the composite material;

[0064] 5) Composite material evaluation: The specific surface area and pore structure of the composite material were determined by nitrogen adsorption-desorption experiments, and the hydrogen adsorption capacity of the composite material was evaluated, including the adsorption amount and release rate;

[0065] 6) Composite material adjustment: Based on the characterization results and hydrogen storage performance, the material applicability is evaluated and the synthesis conditions are adjusted according to the test results to optimize the material performance.

[0066] 2) The reaction temperature is 100-200°C and the reaction time is 12-36H.

[0067] The synthesis conditions in 6) include temperature, time and precursor ratio.

[0068] It should be noted that the graphene in step 1) of the above three embodiments is prepared by a liquid phase exfoliation process, and the liquid phase exfoliation process can obtain graphene nanosheets with controllable size.

[0069] It should be noted that the nanoparticles in step 1) of the above three embodiments are prepared from nickel metal by chemical reduction method.

[0070] It should be noted that the MOFs particles in step 1) of the above three embodiments are ZIF-8 (zinc-imidazole framework) metal organic framework (MOF) materials, which have excellent pore structure and chemical stability, are formed by coordination between zinc ions and imidazole ligands, and have a high specific surface area and adjustable pore size. The synthesis of ZIF-8 is usually performed by solvothermal method or hydrothermal method.

[0071] It should be noted that the solvent in step 3) of the above three embodiments is deionized water or ethanol.

[0072] It should be noted that the MOFs particle precursors in step 1) of the above three embodiments refer to the raw materials or compounds used in the synthesis process. For ZIF-8, the main precursors include: zinc source, zinc acetate (Zn(CH 3 COO 2 ·2H 2 O): Common zinc source, easily soluble in water, can provide zinc ions; zinc chloride (ZnCl 2 ): Another commonly used zinc source with high solubility. Imidazole ligand: Imidazole (C 3 H 4 N 2 ): As an organic ligand, it forms a coordination bond with zinc ions to form the framework structure of ZIF-8.

[0073] The beneficial effects of the present invention are:

[0074] As a key component in composite materials, graphene provides stable structural support for composite materials with its excellent conductivity and mechanical strength. Graphene nanosheets (size between 1-3 microns) form a conductive network in the composite material, which is conducive to the transmission of electrons, thereby promoting the adsorption and desorption process of hydrogen. At the same time, the mechanical strength of graphene also enhances the overall stability of the composite material, enabling it to withstand pressure changes during hydrogen storage. Nanoparticles (size between 5-20 nanometers) as another important component in the composite material provide abundant hydrogen storage sites. These nanoparticles have a high specific surface area and a unique surface structure, which can adsorb a large number of hydrogen molecules. During the hydrogen storage process, hydrogen molecules are adsorbed on the surface and pores of the nanoparticles, thereby achieving efficient hydrogen storage. MOFs particles (size between 20-50 nanometers, surface pore size between 0.3-2 nanometers) provide excellent hydrogen adsorption capacity for composite materials with their high specific surface area and rich pore structure. The pore structure of MOFs particles is conducive to the diffusion and transmission of hydrogen, while the smaller pore size can selectively adsorb hydrogen molecules and improve hydrogen storage efficiency. In addition, the chemical stability and adjustability of MOFs particles also make the composite material show good cycle stability and regeneration performance during the hydrogen storage process. The preparation process of the composite hydrogen storage material includes dissolving graphene, nanoparticles and MOFs precursors in an appropriate solvent to form a uniform mixed solution, then using ultrasonic treatment or mechanical stirring to evenly mix the components, and finally synthesizing them by hydrothermal method or solvothermal method. This preparation process ensures the uniform distribution and full dispersion of each component in the composite material, thereby achieving synergistic effects between the components. In the hydrogen storage process, graphene, nanoparticles and MOFs particles work together to improve the hydrogen storage capacity and hydrogen absorption and desorption rate of the composite material.

[0075] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite hydrogen storage material, characterized in that: The invention comprises the following raw materials in the following weight proportions: 2-10 parts of graphene, 3-8 parts of nanoparticles and 5-10 parts of MOFs particles.

2. A composite hydrogen storage material according to claim 1, characterized in that: The method comprises the following raw materials in the following weight proportions: 5 parts of graphene, 4 parts of nanoparticles, and 6 parts of MOFs particles.

3. A composite hydrogen storage material according to claim 1, characterized in that: The method comprises the following raw materials in the following weight proportions: 6 parts of graphene, 5.5 parts of nanoparticles, and 7 parts of MOFs particles.

4. A composite hydrogen storage material according to claim 1, characterized in that: The invention comprises the following raw materials in the following weight proportions: 8 parts of graphene, 7 parts of nanoparticles and 9 parts of MOFs particles.

5. A composite hydrogen storage material according to claim 1, characterized in that: The graphene is a graphene nanosheet, and the size of the graphene is between 1 and 3 microns.

6. A composite hydrogen storage material according to claim 1, characterized in that: The size of the nanoparticles is between 5 and 20 nanometers.

7. A composite hydrogen storage material according to claim 1, characterized in that: The size of the MOFs particles is between 20-50 nanometers, and the surface pore size of the MOFs particles is between 0.3-2 nanometers.

8. A method for preparing a composite hydrogen storage material, characterized in that: The following steps are involved: 1) Raw material mixing: Dissolve the precursors of graphene, nanoparticles and MOFs in an appropriate solvent to form a uniform mixed solution, and use ultrasonic treatment or mechanical stirring to uniformly mix the graphene, nanoparticles and MOFs to ensure that each component is fully dispersed; 2) Solution synthesis: The mixed solution is transferred to a reaction vessel, and the synthesis is carried out by a hydrothermal method or a solvothermal method, and an appropriate temperature and reaction time are set. After the reaction is completed, the reaction system is cooled, and the solid product is separated by centrifugation or filtration; 3) Pretreatment of the solidified material: washing the solid product with an appropriate solvent to remove unreacted precursors and impurities, drying the washed product in a vacuum drying oven or an oven to remove residual solvent, and obtaining a composite material after the pretreatment is completed; 4) Composite material analysis: Use X-ray diffraction to analyze the crystal structure of the composite material; use scanning electron microscopy and transmission electron microscopy to observe the morphology and microstructure of the composite material; 5) Composite material evaluation: The specific surface area and pore structure of the composite material were determined by nitrogen adsorption-desorption experiments, and the hydrogen adsorption capacity of the composite material was evaluated, including the adsorption amount and release rate; 6) Composite material adjustment: Based on the characterization results and hydrogen storage performance, the material applicability is evaluated and the synthesis conditions are adjusted according to the test results to optimize the material performance.

9. The method for preparing a composite hydrogen storage material according to claim 8, characterized in that: The reaction temperature in 2) is 100-200° C., and the reaction time is 12-36 hours.

10. The method for preparing a composite hydrogen storage material according to claim 8, characterized in that: The synthesis conditions in 6) include temperature, time and precursor ratio.