Multistage-pore MOFs-based composite phase change material, preparation method and application thereof

Abstract

The present application relates to the field of adsorption materials, and discloses a hierarchical pore MOFs-based composite phase change material, a preparation method and application thereof.The MOFs-based composite phase change material comprises a hierarchical pore MOFs material having micropores, mesopores and macropores simultaneously, and a phase change material loaded in the macropore channels of the hierarchical pore MOFs material.The hierarchical pore MOFs-based composite phase change material prepared by the present application has a higher specific surface area and pore volume, and has a certain number of micropores, mesopores and macropores respectively, and the functions of the pore channels of different sizes are fully developed.In the process of adsorbing VOCs in micropores, the mesopores are beneficial to the mass transfer of rapid adsorption of the adsorbate, the adsorption rate is improved, and the phase change material in the macropores can store adsorption heat to inhibit the bed temperature rise and improve the bed adsorption efficiency.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials, specifically to hierarchical porous MOFs-based composite phase change materials, their preparation methods, and applications. Background Technology

[0002] Over the past few decades, traditional porous materials such as molecular sieves, silica gel, and activated carbon have been widely used in selective gas adsorption, gas storage, and gas separation and purification. Compared with traditional adsorption materials such as activated carbon and molecular sieves, metal-organic framework (MOF) materials have advantages such as high specific surface area, high porosity, and diverse framework structures, thus making them promising for applications in gas storage and separation. To date, most reported MOFs have microporous structures, which results in very slow diffusion and mass transfer rates of adsorbed molecules, thus limiting the widespread application of MOF materials in gas adsorption.

[0003] Furthermore, numerous studies have confirmed that gas molecules release or absorb heat during adsorption or desorption on solid surfaces. However, adsorption materials such as activated carbon, molecular sieves, silica gel, and MOFs have relatively poor thermal conductivity. During adsorption, the heat generated accumulates, leading to a significant temperature rise in the entire adsorption bed and consequently, an increase in the gas-solid system temperature, severely reducing the gas adsorption capacity. During desorption, energy absorption causes a temperature drop in the bed, which negatively impacts the desorption process, leaving some gas, especially heavy components, remaining in the adsorbent and affecting its release capacity and lifespan. Adding thermally conductive materials such as graphene and carbon nanotubes to activated carbon and MOFs can improve the thermal conductivity of composite phase change materials, allowing the heat generated in the adsorption bed to dissipate rapidly into the environment and alleviate the temperature rise. However, this method results in significant heat loss and low energy utilization. In addition, the high cost of thermally conductive materials contributes to the high cost of adsorption materials. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of low material adsorption efficiency and difficulty in adsorbing light hydrocarbons caused by the adsorption heat effect in the prior art, and to provide a hierarchical porous MOFs-based composite phase change material, its preparation method and application.

[0005] To achieve the above objectives, the present invention provides a hierarchical porous MOFs-based composite phase change material, wherein the hierarchical porous MOFs-based composite phase change material includes a hierarchical porous MOFs material having micropores, mesopores and macropores simultaneously, and a phase change material loaded within the macropore channels of the hierarchical porous MOFs material.

[0006] Preferably, the ratio of micropore volume, mesopore volume, and macropore volume of the hierarchical porous MOFs material is 1-4:1-2:1.

[0007] Preferably, the specific surface area of ​​the hierarchical porous MOFs material is 600-1700 m². 2 / g.

[0008] Preferably, the phase change material is selected from one or more of polyols, fatty acids, straight-chain alkanes, and paraffin.

[0009] Preferably, the polyol is polyethylene glycol and / or neopentyl glycol.

[0010] Preferably, the fatty acids are selected from one or more of lauric acid, stearic acid, palmitic acid and pentadecanoic acid.

[0011] Preferably, the straight-chain alkane is selected from one or more of n-tetradecane, n-hexadecane, and n-octadecane.

[0012] A second aspect of the present invention provides a method for preparing the above-mentioned hierarchical porous MOFs-based composite phase change material, the method comprising the following steps:

[0013] (1) Mix the metal salt with water to obtain a metal salt solution;

[0014] (2) Mix the template agent, organic ligand and organic solvent to obtain an organic phase solution;

[0015] (3) The metal salt solution is mixed with the organic phase solution and then reacted. After the reaction is completed, the solid and liquid are separated, and the obtained solid is washed and activated in sequence to obtain a hierarchical porous MOF material.

[0016] (4) The phase change material is mixed with an organic solvent to obtain an organic phase change material solution, and the hierarchical porous MOF material is immersed in the organic phase change material solution.

[0017] Preferably, the metal salt is selected from one or more of aluminum trichloride hexahydrate, copper acetate monohydrate, chromium nitrate nonahydrate, zinc nitrate hexahydrate, zirconium chloride, and nickel chloride hexahydrate.

[0018] Preferably, the metal salt content in the metal salt solution is 5-50 g / L.

[0019] Preferably, the template agent is selected from one or more of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and N,N,N,N-tetramethylethylenediamine.

[0020] Preferably, the organic ligand is selected from one or more of 2-methylterephthalic acid, 2-aminoterephthalic acid, 2-nitroterephthalic acid, 2-sulfonic acid terephthalic acid, 2,3-dihydroxyterephthalic acid, terephthalic acid, phthalic acid, trimesic acid, 2,5-thiophene dicarboxylic acid, and triethylenediamine.

[0021] Preferably, the organic ligand is selected from one or more of 2-aminoterephthalic acid, 2,5-thiophene dicarboxylic acid, pyromellitic acid, terephthalic acid, and triethylenediamine.

[0022] Preferably, the organic solvent is selected from one or more of methanol, ethanol, N,N-dimethylformamide, dichloromethane and 1,2-dichloroethane.

[0023] Preferably, the content of the template agent in the organic phase solution is 10-80 g / L, and the content of the organic ligand is 30-150 g / L.

[0024] Preferably, the molar ratio of the metal salt, template agent, and organic ligand is 1:0.03-1:1-2.

[0025] Preferably, in step (3), the reaction conditions include: a temperature of 20-160°C and a time of 6-18h.

[0026] Preferably, the reaction conditions include a temperature of 40-110°C and a time of 8-16 hours.

[0027] Preferably, in step (3), the activation conditions include: a temperature of 80-180°C, a time of 1-24h, and an absolute vacuum of 20-80kPa.

[0028] Preferably, the activation conditions include: a temperature of 100-160℃ and a time of 2-6 hours.

[0029] Preferably, in step (4), the content of phase change material in the organic phase change material solution is 5-80 g / L.

[0030] Preferably, the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.05-0.5.

[0031] Preferably, in step (4), the impregnation conditions include: a time of 4-7 hours and a temperature of 40-70°C.

[0032] A third aspect of the present invention provides an application of the above-mentioned hierarchical porous MOFs-based composite phase change material in the adsorption of VOCs.

[0033] This invention modifies the uniform pore size of traditional MOFs materials with highly uniform pore size distribution, providing MOFs materials with multi-level pore sizes, simultaneously possessing micropores, mesopores, and macropores. The multi-level porous MOFs material serves as a support for phase change materials (PCMs), with the PCM stored within the macropores. This storage of adsorption heat is achieved through the phase change process, improving the adsorption efficiency. The presence of mesopores helps accelerate the mass transfer rate during VOCs adsorption in the MOFs material. The micropores serve as adsorption sites for VOCs, meeting the requirement for high adsorption capacity in the composite material. Attached Figure Description

[0034] Figure 1 This is a nitrogen adsorption isotherm curve of the hierarchical porous MOFs material in Example 1;

[0035] Figure 2 This is a pore size distribution diagram of the hierarchical porous MOFs material in Example 1;

[0036] Figure 3 This is the breakthrough adsorption curve of ethane for the hierarchical porous MOFs material in Example 1;

[0037] Figure 4 This is a pore size distribution diagram of the hierarchical porous MOFs-based composite phase change material in Example 1;

[0038] Figure 5 This is the breakthrough adsorption curve of ethane for the hierarchical porous MOFs-based composite phase change material in Example 1.

[0039] Figure 6 This is the breakthrough adsorption curve of ethane for the hierarchical porous MOFs-based composite phase change material in Example 2.

[0040] Figure 7 This is the breakthrough adsorption curve of ethane by the hierarchical porous MOFs-based composite phase change material in Example 3. Detailed Implementation

[0041] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0042] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0043] The present invention provides a hierarchical porous MOFs-based composite phase change material, which includes a hierarchical porous MOFs material having micropores, mesopores and macropores simultaneously, and a phase change material loaded in the macropore channels of the hierarchical porous MOFs material.

[0044] In this invention, the hierarchical porous MOFs-based composite phase change material comprises a hierarchical porous MOFs material and a phase change material. The hierarchical porous MOFs material has micropores, mesopores and macropores. The phase change material is loaded in the macropore channels of the hierarchical porous MOFs material.

[0045] In this invention, in order to make the hierarchical porous MOFs-based composite phase change material have better adsorption effect and self-temperature control characteristics, it is necessary to reasonably control the ratio of micropores, mesopores and macropores. In a preferred case, the ratio of micropore volume, mesopore volume and macropore volume of the hierarchical porous MOFs material is 1-4:1-2:1, specifically 1:1:1, 2:1:1, 3:1:1, 4:1:1, 1:2:1, 2:2:1, 3:2:1 or 4:2:1.

[0046] Preferably, the specific surface area of ​​the hierarchical porous MOFs material is 600-1700 m². 2 / g, specifically 600m 2 / g、700m 2 / g、800m 2 / g、900m 2 / g, 1000m 2 / g、1100m 2 / g、1200m 2 / g、1300m 2 / g, 1400m 2 / g, 1500m 2 / g, 1600m 2 / g or 1700m 2 / g.

[0047] In this invention, in order to ensure that the phase change materials are all loaded in the macropores of the hierarchical porous MOFs-based composite phase change materials, it is preferred that the phase change materials are all macromolecular phase change materials. More preferably, the phase change materials are selected from one or more of polyols, fatty acids, straight-chain alkanes and paraffins.

[0048] Preferably, the polyol is polyethylene glycol and / or neopentyl glycol.

[0049] Preferably, the fatty acids are selected from one or more of lauric acid, stearic acid, palmitic acid and pentadecanoic acid.

[0050] Preferably, the straight-chain alkane is selected from one or more of n-tetradecane, n-hexadecane, and n-octadecane.

[0051] In this invention, when the phase change material contains paraffin, in order to ensure that the adsorption process can be controlled at a low temperature, it is more suitable to select paraffin with a phase change temperature of 30-50°C, and more preferably paraffin with a phase change temperature of 38°C.

[0052] A second aspect of the present invention provides a method for preparing the above-mentioned hierarchical porous MOFs-based composite phase change material, the method comprising the following steps:

[0053] (1) Mix the metal salt with water to obtain a metal salt solution;

[0054] (2) Mix the template agent, organic ligand and organic solvent to obtain an organic phase solution;

[0055] (3) The metal salt solution is mixed with the organic phase solution and then reacted. After the reaction is completed, the solid and liquid are separated, and the obtained solid is washed and activated in sequence to obtain a hierarchical porous MOF material.

[0056] (4) The phase change material is mixed with an organic solvent to obtain an organic phase change material solution, and the hierarchical porous MOF material is immersed in the organic phase change material solution.

[0057] In this invention, the metal salts are all selected from soluble metal salts and / or slightly soluble metal salts.

[0058] Preferably, the metal salt is selected from aluminum trichloride, aluminum trichloride hexahydrate, aluminum nitrate, aluminum sulfate, aluminum acetate, ferric trichloride, ferric trichloride hexahydrate, ferric sulfate, ferric nitrate, ferric acetate, copper chloride, copper sulfate, copper nitrate, copper acetate, copper acetate monohydrate, copper sulfate pentahydrate, copper nitrate trihydrate, chromium nitrate, chromium chloride, chromium sulfate, chromium acetate, chromium nitrate nonahydrate, chromium chloride hexahydrate, zirconium nitrate, zirconium chloride, zirconium sulfate, zirconium acetate, zirconium nitrate pentahydrate, and nitrate. One or more of the following: zinc nitrate, zinc chloride, zinc sulfate, zinc acetate, zinc nitrate hexahydrate, zinc sulfate heptahydrate, nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, nickel sulfate hexahydrate, nickel nitrate hexahydrate, nickel chloride hexahydrate, cobalt nitrate, cobalt chloride, cobalt sulfate, cobalt acetate, cobalt chloride hexahydrate, cobalt nitrate hexahydrate, cobalt sulfate monohydrate, manganese nitrate, manganese chloride, manganese sulfate, manganese acetate, manganese sulfate monohydrate, manganese nitrate hexahydrate, and manganese acetate dihydrate.

[0059] Preferably, the metal salt is selected from one or more of aluminum trichloride hexahydrate, copper acetate monohydrate, chromium nitrate nonahydrate, zinc nitrate hexahydrate, zirconium chloride, and nickel chloride hexahydrate.

[0060] In a preferred embodiment, in step (1), the content of the metal salt in the metal salt solution is 5-50 g / L, specifically 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L or 50 g / L.

[0061] Preferably, the template agent is selected from one or more of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123), hexadecyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate, and N,N,N,N-tetramethylethylenediamine.

[0062] Preferably, the organic ligand is selected from one or more of 2-methylterephthalic acid, 2-aminoterephthalic acid, 2-nitroterephthalic acid, 2-sulfonic acid terephthalic acid, 2,3-dihydroxyterephthalic acid, terephthalic acid, phthalic acid, trimesic acid, 2,5-thiophene dicarboxylic acid, and triethylenediamine.

[0063] More preferably, the organic ligand is selected from one or more of 2-aminoterephthalic acid, 2,5-thiophene dicarboxylic acid, pyromellitic acid, terephthalic acid, and triethylenediamine.

[0064] In a preferred embodiment, in step (2), the organic solvent is selected from one or more of methanol, ethanol, N,N-dimethylformamide (DMF), dichloromethane, and 1,2-dichloroethane.

[0065] In a preferred embodiment, in step (2), the content of the template agent in the organic phase solution is 10-80 g / L, and the content of the organic ligand is 30-150 g / L.

[0066] In a specific embodiment, in step (2), the content of the template agent in the organic phase solution can be 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L or 80 g / L, and the content of the organic ligand in the organic phase solution can be 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L or 150 g / L.

[0067] In the preparation method described in this invention, under preferred conditions, the molar ratio of the metal salt, template agent, and organic ligand is 1:0.03-1:1-2. The organic ligand is more abundant than the metal salt to ensure that unreacted organic ligands can be washed away with organic solvents after the hierarchical porous MOFs material is generated. However, excessive template agent will lead to a serious reduction in the quality of the hierarchical porous MOFs material. Therefore, it is necessary to control the ratio of each raw material within the above range.

[0068] In specific embodiments, the molar ratio of the metal salt, template agent, and organic ligand can be 1:0.03:1, 1:0.04:1, 1:0.05:1, 1:0.06:1, 1:0.07:1, 1:0.08:1, 1:0.09:1, 1:1:1, 1:0.03:2, 1:0.04:2, 1:0.05:2, 1:0.06:2, 1:0.07:2, 1:0.08:2, 1:0.09:2, or 1:1:2.

[0069] In a preferred embodiment of the present invention, in step (3), the reaction conditions include: a temperature of 20-160°C and a time of 6-18h.

[0070] More preferably, in step (3), the reaction conditions include: a temperature of 40-110°C and a time of 8-16h.

[0071] In a specific implementation, in step (3), the reaction temperature can be 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or 110°C, and the reaction time can be 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h or 16h.

[0072] In step (3) of the present invention, the obtained solid can be washed with an organic solvent to remove unreacted metal salts, template agents and organic ligands, etc. The organic solvent can be selected from one or more of methanol, ethanol, N,N-dimethylformamide, dichloromethane and 1,2-dichloroethane, preferably anhydrous ethanol for washing.

[0073] In step (3) of this invention, there are no special requirements for the number of washing cycles; the goal is to remove unreacted metal salts, template agents, and organic ligands.

[0074] In a preferred embodiment of the present invention, the activation conditions in step (3) include: a temperature of 80-180°C, a time of 1-24 h, and an absolute vacuum of 20-80 kPa.

[0075] More preferably, in step (3), the activation temperature is 100-160℃ and the activation time is 2-6h.

[0076] In a specific implementation, in step (3), the activation temperature can be 100℃, 110℃, 120℃, 130℃, 140℃, 150℃ or 160℃, the activation time can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, and the absolute vacuum degree of activation can be 20kPa, 25kPa, 30kPa, 35kPa, 40kPa, 45kPa, 50kPa, 55kPa, 60kPa, 65kPa, 70kPa, 75kPa or 80kPa.

[0077] In a preferred embodiment, in step (4), the organic solvent is selected from one or more of methanol, ethanol, N,N-dimethylformamide, dichloromethane and 1,2-dichloroethane, and more preferably anhydrous ethanol.

[0078] In step (4) of the present invention, in order to ensure that the phase change materials are all loaded in the macropores of the multi-level porous MOFs-based composite phase change materials, it is preferred that the phase change materials are all macromolecular phase change materials. More preferably, the phase change materials are selected from one or more of polyols, fatty acids, straight-chain alkanes and paraffins.

[0079] Preferably, the polyol is polyethylene glycol and / or neopentyl glycol.

[0080] Preferably, the fatty acids are selected from one or more of lauric acid, stearic acid, palmitic acid and pentadecanoic acid.

[0081] Preferably, the straight-chain alkane is selected from one or more of n-tetradecane, n-hexadecane, and n-octadecane.

[0082] In this invention, when the phase change material contains paraffin, in order to ensure that the adsorption process can be controlled at a low temperature, it is more suitable to select paraffin with a phase change temperature of 30-50°C, and more preferably paraffin with a phase change temperature of 38°C.

[0083] In a preferred embodiment of the present invention, in step (4), the content of phase change material in the organic phase change material solution is 5-80 g / L.

[0084] In a specific implementation, in step (4), the content of phase change material in the organic phase change material solution can be 5 g / L, 15 g / L, 25 g / L, 35 g / L, 45 g / L, 55 g / L, 65 g / L, 75 g / L or 80 g / L.

[0085] Preferably, in step (4), the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.05-0.5, specifically 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45 or 1:0.5.

[0086] In a preferred embodiment of the present invention, in step (4), the conditions for impregnation include: a time of 4-7 hours and a temperature of 40-70°C.

[0087] In a specific implementation, in step (4), the soaking time can be 4h, 4.5h, 5h, 5.5h, 6h, 6.5h or 7h, and the soaking temperature can be 40℃, 45℃, 50℃, 55℃, 60℃, 65℃ or 70℃.

[0088] In step (4) of the present invention, after impregnation is completed, filtration is required, and the solid obtained by filtration is dried.

[0089] In this invention, by controlling the ratio of hierarchical porous MOFs material to organic phase change material and the impregnation conditions, a suitable hierarchical porous MOFs-based composite phase change material can be obtained.

[0090] In this invention, the drying conditions include a temperature of 60-70°C and a time of 4-6 hours.

[0091] In a specific implementation, the drying temperature can be 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃ or 70℃, and the drying time can be 4h, 4.5h, 5h, 5.5h or 6h.

[0092] The multi-level porous MOFs-based composite phase change material prepared by the above preparation method in this invention contains 5-30% by weight of phase change material. In specific embodiments, the content of phase change material in the multi-level porous MOFs-based composite phase change material can be 5% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, or 30% by weight.

[0093] A third aspect of the present invention provides an application of the above-mentioned hierarchical porous MOFs-based composite phase change material in the adsorption of VOCs.

[0094] In this invention, under the action of a suitable template agent, the self-assembly of metal salts and organic ligands is restricted, and the original periodic network structure is disrupted. Simultaneously, by controlling the amount of template agent added and the reaction conditions, a hierarchical porous MOF material with microporous, mesoporous, and macroporous structures is obtained. This hierarchical porous MOF material possesses a three-dimensional ordered interconnected structure, adjustable pore size, and ultra-large specific surface area, making it suitable as a carrier for phase change materials. Based on the hierarchical porous MOF material, phase change materials are introduced into the macroporous channels. Compared to traditional MOF materials, during the microporous adsorption of VOCs, the mesoporous channels in the hierarchical pores facilitate adsorbate diffusion, accelerate mass transfer, and improve the adsorption rate. Meanwhile, the phase change material in the macropores counteracts the adsorption heat effect through phase change, controlling the temperature rise of the bed and significantly improving the adsorption efficiency. Therefore, the hierarchical porous MOF material loaded with phase change materials has the function of storing adsorption heat, effectively reducing the bed temperature rise during VOCs adsorption.

[0095] The multi-level porous MOFs-based composite phase change material of the present invention has the characteristics of high phase change material loading rate, low bed temperature rise and fast adsorption rate. It can be used in the field of VOCs treatment, especially for adsorbing light hydrocarbons, such as small molecules such as ethane and propane. It has broad application prospects in the adsorption and treatment of VOCs and has achieved good technical results.

[0096] Compared with the prior art, the present invention has the following advantages:

[0097] (1) The present invention uses the addition of template agent to synthesize hierarchical porous MOFs material, and the porous coordination polymer is more uniformly and densely distributed on the surface.

[0098] (2) The synthesis method of this invention is simple, avoiding cumbersome preparation processes and operating conditions, and is suitable for large-scale preparation and use. Multi-level porous materials can be synthesized in one step, and self-temperature-controlled adsorbent materials can be obtained using a simple impregnation method, which has the prospect of large-scale production and application.

[0099] (3) The multi-level porous MOFs-based composite phase change material prepared by the present invention uses multi-level porous MOFs material as the matrix, which has a high specific surface area and pore volume, and has a certain number of micropores, mesopores and macropores respectively. It fully develops the functions of channels of different sizes. In the process of micropore adsorption of VOCs, mesopores are conducive to the mass transfer of fast adsorbate and improve the adsorption rate. The phase change material in macropores can store adsorption heat and suppress bed temperature rise.

[0100] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0101] In the following examples, copper acetate monohydrate, triethylenediamine, zinc nitrate hexahydrate, and aluminum trichloride hexahydrate are all products of Shanghai Aladdin Biochemical Technology Co., Ltd.; chromium nitrate nonahydrate, zirconium chloride, nickel chloride hexahydrate, pyromellitic acid, 2,5-thiophene dicarboxylic acid, and 2-aminoterephthalic acid are all products of Shanghai Maclean Biochemical Technology Co., Ltd.; CTAB is a product of Beijing Innocare Technology Co., Ltd.; terephthalic acid is a product of Shanghai Kaishu Chemical Technology Co., Ltd.; n-octadecane is a product of Tianjin Xiens Biochemical Technology Co., Ltd.; 38°C and 45°C phase change paraffins are products of Shanghai Rushang New Energy Technology Co., Ltd.; and anhydrous ethanol and DMF are products of China National Pharmaceutical Group Co., Ltd.

[0102] All room temperatures mentioned below refer to 25°C.

[0103] Example 1

[0104] (1) Add 2.8g of metal salt (copper acetate monohydrate) to a beaker containing water and sonicate at room temperature to mix it evenly, so as to obtain a metal salt solution (the metal salt content is 35g / L).

[0105] (2) Add 3.1g template agent (CTAB) and 3.8g organic ligand (tristyric acid) to a beaker containing organic solvent (anhydrous ethanol), and sonicate at room temperature to mix them evenly to obtain an organic phase solution (the content of template agent is 26g / L and the content of organic ligand is 32g / L).

[0106] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are added together into a reaction flask (the molar ratio of metal salt, template agent and organic ligand is 1:0.61:1.29), placed in an oil bath, and reacted at 40°C for 8 hours. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged. The obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 100°C and an absolute vacuum of 40 kPa for 6 hours to obtain hierarchical porous MOFs material B1.

[0107] (4) Add 0.6g of phase change material (paraffin with a phase change temperature of 38℃) to an organic solvent (anhydrous ethanol), heat and stir at 60℃ until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 60g / L). Place 1.5g of the hierarchical porous MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.4), immerse at 40℃ for 5h, then filter, and dry the obtained solid at 60℃ for 4h to obtain hierarchical porous MOFs-based composite phase change material A1.

[0108] Example 2

[0109] (1) Add 3.1g of metal salt (aluminum trichloride hexahydrate) to a beaker containing water and sonicate at room temperature to mix it evenly, so as to obtain a metal salt solution (the metal salt content is 45g / L);

[0110] (2) Add 3.6g of template agent (CTAB) and 3.5g of organic ligand (2,5-thiophene dicarboxylic acid) to a beaker containing organic solvent (DMF), and sonicate at room temperature to mix them evenly to obtain an organic phase solution (the content of template agent is 60g / L and the content of organic ligand is 58g / L).

[0111] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are added together into a reaction flask (the molar ratio of metal salt, template agent and organic ligand is 1:0.77:1.58), placed in an oil bath, and reacted at 100℃ for 9h. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged and the obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 120℃ and an absolute vacuum of 40kPa for 4h to obtain hierarchical porous MOFs material.

[0112] (4) Add 0.6g of phase change material (paraffin with a phase change temperature of 38℃) to an organic solvent (anhydrous ethanol), heat and stir at 60℃ until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 60g / L). Place 2g of the hierarchical porous MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.3), immerse at 70℃ for 5h, then filter, and dry the obtained solid at 60℃ for 4h to obtain hierarchical porous MOFs-based composite phase change material A2.

[0113] Example 3

[0114] (1) Add 4g of metal salt (chromium nitrate nonahydrate) to a beaker containing water and sonicate at room temperature to mix it evenly, so as to obtain a metal salt solution (the content of metal salt is 44g / L).

[0115] (2) Add 2.6g template agent (CTAB) and 3.4g organic ligand (2-aminoterephthalic acid) to a beaker containing organic solvent (anhydrous ethanol), and sonicate at room temperature to mix them evenly to obtain an organic phase solution (the content of template agent is 50g / L and the content of organic ligand is 65g / L).

[0116] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are transferred into the reaction vessel (the molar ratio of metal salt, template agent and organic ligand is 1:0.71:1.88), placed in an oven, and reacted at 90℃ for 12h. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged and the obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 120℃ and an absolute vacuum of 60kPa for 4h to obtain hierarchical porous MOFs material.

[0117] (4) Add 0.5g of phase change material (paraffin with a phase change temperature of 38℃) to an organic solvent (anhydrous ethanol), heat and stir at 60℃ until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 50g / L). Place 1.5g of the hierarchical porous MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.33), immerse at 60℃ for 5h, then filter, and dry the obtained solid at 60℃ for 4h to obtain hierarchical porous MOFs-based composite phase change material A3.

[0118] Example 4

[0119] (1) Add 2.5g of metal salt (zinc nitrate hexahydrate) to a beaker containing water and sonicate at room temperature to mix it evenly, so as to obtain a metal salt solution (the metal salt content is 30g / L);

[0120] (2) Add 2.6g template agent (CTAB) and 1.9g organic ligand (terephthalic acid) to a beaker containing organic solvent (DMF), and sonicate at room temperature to mix them evenly to obtain an organic phase solution (the content of template agent is 60g / L and the content of organic ligand is 44g / L).

[0121] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are transferred into the reaction vessel (the molar ratio of metal salt, template agent and organic ligand is 1:0.84:1.36), placed in an oven, and reacted at 110℃ for 13h. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged and the obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 140℃ and an absolute vacuum of 60kPa for 6h to obtain hierarchical porous MOFs material.

[0122] (4) Add 0.5g of phase change material (paraffin with a phase change temperature of 38℃) to an organic solvent (anhydrous ethanol), heat and stir at 60℃ until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 50g / L). Place 2g of the hierarchical porous MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.25), immerse at 50℃ for 5h, then filter, and dry the obtained solid at 60℃ for 4h to obtain hierarchical porous MOFs-based composite phase change material A4.

[0123] Example 5

[0124] (1) Add 1.2g of metal salt (zirconium chloride) to a beaker containing water and sonicate at room temperature to mix it evenly, so as to obtain a metal salt solution (the metal salt content is 35g / L);

[0125] (2) Add 1.6g template agent (CTAB) and 1.1g organic ligand (terephthalic acid) to a beaker containing organic solvent (DMF), and sonicate at room temperature to mix them evenly to obtain an organic phase solution (the content of template agent is 70g / L and the content of organic ligand is 48g / L).

[0126] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are transferred into the reaction vessel (the molar ratio of metal salt, template agent and organic ligand is 1:0.85:1.29), placed in an oven, and reacted at 90℃ for 12h. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged and the obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 120℃ and an absolute vacuum of 60kPa for 4h to obtain hierarchical porous MOFs material.

[0127] (4) Add 0.3g of phase change material (paraffin with a phase change temperature of 38℃) to an organic solvent (anhydrous ethanol), heat and stir at 60℃ until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 37.5g / L). Place 3g of the hierarchical porous MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.1), immerse at 40℃ for 5h, then filter, and dry the obtained solid at 60℃ for 4h to obtain hierarchical porous MOFs-based composite phase change material A5.

[0128] Example 6

[0129] (1) Add 0.6g of metal salt (nickel chloride hexahydrate) to a beaker containing water and sonicate at room temperature to mix it evenly to obtain a metal salt solution (the metal salt content is 35g / L);

[0130] (2) Add 0.8g template agent (CTAB) and 0.6g organic ligand (0.4g terephthalic acid and 0.2g triethylenediamine) to a beaker containing organic solvent (DMF), and sonicate at room temperature to mix them evenly to obtain an organic phase solution (the content of template agent is 50g / L and the content of organic ligand is 38g / L);

[0131] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are transferred into the reaction vessel (the molar ratio of the amount of metal salt, template agent and organic ligand is 1:0.86:1.66), placed in an oven, and reacted at 110℃ for 16h. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged and the obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 120℃ with an absolute vacuum of 60kPa for 4h to obtain hierarchical porous MOFs material.

[0132] (4) Add 0.2g of phase change material (paraffin with a phase change temperature of 38℃) to an organic solvent (anhydrous ethanol), heat and stir at 60℃ until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 40g / L). Place 2g of the hierarchical porous MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.1), immerse at 50℃ for 5h, then filter, and dry the obtained solid at 60℃ for 4h to obtain hierarchical porous MOFs-based composite phase change material A6.

[0133] Example 7

[0134] The method of Example 1 was carried out, except that the phase change material used was n-octadecane, and a hierarchical porous MOFs-based composite phase change material A7 was obtained.

[0135] Example 8

[0136] The method of Example 2 was implemented, except that the phase change material used was n-octadecane, to obtain hierarchical porous MOFs-based composite phase change material A8.

[0137] Example 9

[0138] The method of Example 3 was implemented, except that the phase change material used was n-octadecane, to obtain hierarchical porous MOFs-based composite phase change material A9.

[0139] Example 10

[0140] The method of Example 1 was implemented, except that the phase change material used was paraffin with a phase change temperature of 45°C, to obtain a hierarchical porous MOFs-based composite phase change material A10.

[0141] Example 11

[0142] The method of Example 2 was implemented, except that the phase change material used was paraffin with a phase change temperature of 45°C, to obtain a hierarchical porous MOFs-based composite phase change material A11.

[0143] Comparative Example 1

[0144] (1) Add 2.8g of metal salt (copper acetate monohydrate) to a beaker containing water and sonicate at room temperature to mix it evenly, so as to obtain a metal salt solution (the metal salt content is 35g / L).

[0145] (2) Add 3.8g of organic ligand (tristyric acid) to a beaker containing organic solvent (anhydrous ethanol), and sonicate at room temperature to mix it evenly to obtain an organic phase solution (the content of organic ligand is 32g / L);

[0146] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are added together into a reaction flask (the molar ratio of the metal salt and the organic ligand is 1:1.29), placed in an oil bath, and reacted at 40°C for 8 hours. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged and the obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 100°C and an absolute vacuum of 60 kPa for 6 hours to obtain MOF material D1-1.

[0147] (4) Add 0.6g of phase change material (paraffin with a phase change temperature of 38℃) to an organic solvent (anhydrous ethanol), heat and stir at 60℃ until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 60g / L). Place 1.5g of MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of MOFs material to organic phase change material is 1:0.4), immerse at 40℃ for 5h, then filter, and dry the obtained solid at 60℃ for 4h to obtain MOFs-based composite phase change material D1-2.

[0148] Comparative Example 2

[0149] (1) Add 3.1g of metal salt (aluminum trichloride hexahydrate) to a beaker containing water and sonicate at room temperature to mix it evenly, so as to obtain a metal salt solution (the metal salt content is 45g / L);

[0150] (2) Add 3.5g of organic ligand (2,5-thiophene dicarboxylic acid) to a beaker containing organic solvent (DMF), and sonicate at room temperature to mix it evenly to obtain an organic phase solution (the content of organic ligand is 58g / L);

[0151] (3) The metal salt solution obtained in step (1) and the organic phase solution obtained in step (2) are added together into a reaction flask (the molar ratio of the metal salt to the organic ligand is 1:1.58), placed in an oil bath, and reacted at 100°C for 9 hours. After the reaction is completed, a suspension is obtained. After the suspension is cooled to room temperature, it is centrifuged and the obtained solid is washed twice with anhydrous ethanol. Then the washed solid is placed in a vacuum oven and activated at 120°C and an absolute vacuum of 60 kPa for 4 hours to obtain MOFs material.

[0152] (4) Add 0.6g of phase change material (n-octadecane) to an organic solvent (anhydrous ethanol), heat and stir at 60°C until completely dissolved to obtain an organic phase change material solution (the content of phase change material is 60g / L). Place 2g of MOFs material obtained in step (3) into the organic phase change material solution (the weight ratio of MOFs material to organic phase change material is 1:0.3), immerse at 70°C for 5h, then filter, and dry the obtained solid at 60°C for 4h to obtain MOFs-based composite phase change material D2.

[0153] Test Example 1

[0154] The specific surface area, total pore volume, pore size, maximum temperature of adsorption process, ethane adsorption amount and breakthrough point adsorption rate of A1-A11, B1, D1-1, D1-2 and D2 were measured respectively.

[0155] Test instrument: BSD-PM2 specific surface area analyzer from Best Instruments Technology (Beijing) Co., Ltd.;

[0156] Powder samples of approximately 100 mg were weighed and degassed under vacuum at 150 °C for 12 h. The corresponding data were obtained by molecular testing with nitrogen as a probe at liquid nitrogen temperature (-196 °C).

[0157] Among them, specific surface area (S BET The Brunauer-Emmet-Teller (BET) equation was used for calculations, with relative pressures ranging from 0.01 to 0.15, requiring a correlation coefficient greater than 0.999 and a C value greater than 0. The total pore volume was derived from the N2 adsorption amount at a relative pressure of 0.99. The pore size distribution was obtained using nonlocal density function theory (NLDFT).

[0158] The breakthrough adsorption curves of ethane gas for each sample were determined using a multi-component adsorption breakthrough curve analyzer (BSD-MAB) from Best Instruments Technology (Beijing) Co., Ltd., and the adsorption amount of ethane was calculated. The highest temperature during the adsorption process was measured by the temperature sensor on the analyzer.

[0159] The specific procedure for determining the breakthrough curve of ethane gas is as follows: First, weigh approximately 150g of sample and load it into the breakthrough column. Purge the column with helium gas at a flow rate of 300ml / min for 2 hours to remove impurities from the sample surface. Place the breakthrough column in a constant temperature water bath at 298K. After the test environment stabilizes, begin the breakthrough experiment and test the ethane breakthrough adsorption curve (gas flow rate 900mL / min, ethane concentration 10% VOL, test temperature and pressure 25℃ and 5bar, respectively), and calculate the adsorption capacity.

[0160] The adsorption capacity of each component is calculated using the following formula:

[0161]

[0162] Note: This calculation formula takes into account the concentration changes caused by real-time changes in the outlet flow rate due to adsorption, which improves the accuracy of calculating the adsorption amount by concentration integral.

[0163] Q n吸附 Adsorption capacity of the adsorbent for adsorbate n (unit: mL)

[0164] Q n入总 Total flow rate of adsorbate n into the breakthrough column over time ΔT (unit: mL)

[0165] Q n出总 : Total flow rate of adsorbate n through the column during time ΔT (unit: mL)

[0166] q 总入 Total gas velocity at the inlet of the penetration column (unit: mL / min)

[0167] q 载气 Carrier gas flow rate (unit: mL / min)

[0168] C n0 : Percentage concentration (%) of adsorbate n at the inlet of the permeation column

[0169] C nt : Percentage concentration (%) of adsorbate n at the outlet of the permeation column at a certain moment.

[0170] ΔT: Total time from the start to the end of adsorption (unit: s) for the adsorption amount of each component.

[0171] Formula for calculating the penetration point adsorption rate:

[0172]

[0173] Q: The amount of adsorbate n adsorbed when the adsorbent is permeated (unit: mL / g)

[0174] t: Time taken for the adsorbent to permeate (unit: min)

[0175] The results are shown in Table 1 and , respectively. Figure 1-7 As shown ( Figure 1 The nitrogen adsorption isotherm curve for B1; Figure 2 The aperture distribution range of B1, Figure 3 This is the breakthrough adsorption curve of B1 for ethane. Figure 4 The aperture distribution range of A1, Figure 5 This is the breakthrough adsorption curve of A1 for ethane. Figure 6 This is the breakthrough adsorption curve of A2 for ethane. Figure 7 (This is the breakthrough adsorption curve of A3 for ethane).

[0176] Table 1

[0177]

[0178] Figure 1 and Figure 2 The nitrogen adsorption isotherm and pore size distribution of B1 are presented. The figures show that a hierarchical porous MOF material was generated under the action of the template agent. Figure 2 It can be seen that B1 simultaneously possesses micropores, mesopores, and macropores, with a micropore volume, mesopore volume, and macropore volume ratio of 1.76:1.28:1. Table 1 presents the pore structure data, adsorption temperature rise, and adsorption capacity of the composite materials. Because the phase change material occupies a certain pore volume, the pore volume of A1 is smaller than that of B1 and D1-1. During ethane adsorption, the material absorbs adsorption heat during phase change, resulting in the lowest temperature rise for A1. A lower temperature is more favorable for ethane adsorption, therefore, the ethane adsorption capacity of A1 is higher than that of B1 and D1-1.

[0179] Examples 1-6 illustrate that this method forms porous MOF materials under the action of a template agent, which can be combined with phase change materials to form self-temperature-controlled adsorbent materials. The pore volume of the obtained materials is 0.3-0.5 mL / g, and the ethane adsorption capacity is 63-74 mL / g, with a temperature rise of 13-16℃ due to ethane adsorption. Materials A7 and A8 show that the composite material with added n-octadecane can suppress the adsorption temperature rise through the phase change process, but it has a certain impact on the pore structure of the adsorbent material.

[0180] Comparing Example 1 and Comparative Example 1, material A1 is a composite of hierarchical porous MOFs and phase change materials, while material D1-2 has a microporous structure. It is difficult for the phase change material to enter the micropores, so there are significant differences in the temperature control effect and adsorption performance of the two materials. Since the phase change material is difficult to enter the micropores, the structures and performance of D1-1 and D1-2 are basically similar. Similarly, the phase change material in Comparative Example 2 is also difficult to enter the micropores, so D2 does not have the function of phase change temperature control, and the ethane adsorption capacity of D2 is low.

[0181] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A hierarchical porous MOFs-based composite phase change material, characterized in that, The hierarchical porous MOFs-based composite phase change material is used to adsorb VOCs. The hierarchical porous MOFs-based composite phase change material includes a hierarchical porous MOFs material having micropores, mesopores and macropores simultaneously, and a phase change material loaded in the macropore channels of the hierarchical porous MOFs material; the ratio of the micropore volume, mesopore volume and macropore volume of the hierarchical porous MOFs material is 1-4:1-2:

1. The hierarchical porous MOFs-based composite phase change material was prepared by the following method: (1) Mix the metal salt with water to obtain a metal salt solution; (2) Mix the template agent, organic ligand and organic solvent to obtain an organic phase solution; (3) The metal salt solution is mixed with the organic phase solution and then reacted. After the reaction is completed, the solid and liquid are separated, and the obtained solid is washed and activated in sequence to obtain a hierarchical porous MOF material. (4) Mix the phase change material with an organic solvent to obtain an organic phase change material solution, and then immerse the hierarchical porous MOF material in the organic phase change material solution. The molar ratio of the metal salt, template agent, and organic ligand is 1:0.03-1:1-2.

2. The hierarchical porous MOFs-based composite phase change material according to claim 1, characterized in that, The specific surface area of ​​the hierarchical porous MOFs material is 600-1700 m². 2 / g.

3. The hierarchical porous MOFs-based composite phase change material according to claim 1 or 2, characterized in that, The phase change material is selected from one or more of polyols, fatty acids, straight-chain alkanes, and paraffins.

4. The hierarchical porous MOFs-based composite phase change material according to claim 3, characterized in that, The polyols are polyethylene glycol and / or neopentyl glycol.

5. The hierarchical porous MOFs-based composite phase change material according to claim 3, characterized in that, The fatty acids are selected from one or more of lauric acid, stearic acid, palmitic acid, and pentadecanoic acid.

6. The hierarchical porous MOFs-based composite phase change material according to claim 3, characterized in that, The straight-chain alkane is selected from one or more of n-tetradecane, n-hexadecane, and n-octadecane.

7. The hierarchical porous MOFs-based composite phase change material according to claim 1, characterized in that, In step (1), the metal salt is selected from one or more of aluminum trichloride hexahydrate, copper acetate monohydrate, chromium nitrate nonahydrate, zinc nitrate hexahydrate, zirconium chloride and nickel chloride hexahydrate.

8. The hierarchical porous MOFs-based composite phase change material according to claim 1 or 7, characterized in that, In step (1), The metal salt content in the metal salt solution is 5-50 g / L.

9. The hierarchical porous MOFs-based composite phase change material according to claim 1 or 7, characterized in that, The template agent is selected from one or more of the following: polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and N,N,N,N-tetramethylethylenediamine.

10. The hierarchical porous MOFs-based composite phase change material according to claim 1, characterized in that, The organic ligand is selected from one or more of 2-methylterephthalic acid, 2-aminoterephthalic acid, 2-nitroterephthalic acid, 2-sulfonic acid terephthalic acid, 2,3-dihydroxyterephthalic acid, terephthalic acid, phthalic acid, trimesic acid, 2,5-thiophene dicarboxylic acid, and triethylenediamine.

11. The hierarchical porous MOFs-based composite phase change material according to claim 10, characterized in that, The organic ligand is selected from one or more of 2-aminoterephthalic acid, 2,5-thiophene dicarboxylic acid, pyromellitic acid, terephthalic acid, and triethylenediamine.

12. The hierarchical porous MOFs-based composite phase change material according to claim 1, characterized in that, The organic solvent is selected from one or more of methanol, ethanol, N,N-dimethylformamide, dichloromethane, and 1,2-dichloroethane.

13. The hierarchical porous MOFs-based composite phase change material according to claim 1, characterized in that, The content of the template agent in the organic phase solution is 10-80 g / L, and the content of the organic ligand is 30-150 g / L.

14. The hierarchical porous MOFs-based composite phase change material according to claim 1, characterized in that, In step (3), the reaction conditions include a temperature of 20-160°C and a time of 6-18h.

15. The hierarchical porous MOFs-based composite phase change material according to claim 14, characterized in that, The reaction conditions include a temperature of 40-110℃ and a time of 8-16h.

16. The hierarchical porous MOFs-based composite phase change material according to claim 1 or 15, characterized in that, In step (3), the activation conditions include: a temperature of 80-180℃, a time of 1-24h, and an absolute vacuum of 20-80kPa.

17. The hierarchical porous MOFs-based composite phase change material according to claim 16, characterized in that, The activation temperature is 100-160℃, and the activation time is 2-6 hours.

18. The hierarchical porous MOFs-based composite phase change material according to claim 1, characterized in that, In step (4), the content of phase change material in the organic phase change material solution is 5-80 g / L.

19. The hierarchical porous MOFs-based composite phase change material according to claim 18, characterized in that, The weight ratio of the hierarchical porous MOFs material to the organic phase change material is 1:0.05-0.

5.

20. The hierarchical porous MOFs-based composite phase change material according to claim 1 or 18, characterized in that, In step (4), the conditions for impregnation include: a time of 4-7 hours and a temperature of 40-70°C.

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