A composite phase change material with photothermal synergistic catalytic performance and its preparation method and application

Abstract

The present invention belongs to the technical field of composite phase change materials, and specifically relates to a composite phase change material with photothermal synergistic catalytic performance, and its preparation method and application. The present invention uses metal organic framework (MOFs) material as a template, and obtains transition metal-based hydrotalcite (LDHs) with uniform metal element distribution through chemical etching of transition metal salts; then LDHs is used as a carrier to compound with organic phase change materials. The composite phase change material with photothermal synergistic catalytic performance in the present invention exhibits excellent photothermal effect under the illumination of simulated sunlight xenon lamp, and can effectively promote the adsorption and activation of carbon dioxide; at the same time, it can quickly increase the temperature around the active site, promote the contact between the reaction substrate and the catalytic active site, and can exhibit excellent photothermal synergistic catalytic CO2 conversion activity under low temperature conditions, thereby realizing efficient and rapid photothermal energy storage and conversion and photothermal synergistic catalytic applications, and the preparation method is simple and has good economy.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite phase change materials, and specifically relates to a composite phase change material with photothermal synergistic catalytic performance, a preparation method thereof, and an application thereof. Background Art

[0002] Fossil energy reserves are limited, and their use can cause environmental pollution and the greenhouse effect. Solar energy is abundant, clean, and easily accessible and widely used. Converting solar energy into thermal energy is the most basic way to utilize it, but its random spatial and temporal distribution limits its further development. Phase change materials (PCMs) are functional materials that can reversibly store and release latent heat during an isothermal phase change process. PCMs can store the heat generated by photothermal components when excited by sunlight and release it when needed, thereby resolving the problem of unstable supply and demand of solar energy and thermal energy caused by temporal and spatial differences.

[0003] CO2 conversion can achieve its effective utilization while consuming CO2, converting it into high-value-added chemicals and fuels, and helping to achieve carbon peak and carbon neutrality. However, the activation process of CO2 is limited by its extremely large C=O dissociation energy, which means that CO2 conversion needs to be carried out under extremely harsh conditions and at the expense of high energy costs to achieve a satisfactory CO2 conversion rate. Currently, scientists are committed to integrating photothermal and synergistic catalysis to achieve the conversion of carbon dioxide to carbon-containing fuels under mild conditions.

[0004] However, there is currently a lack of photothermal synergistic catalytic materials with good light absorption capacity, photothermal conversion capacity and abundant catalytic active centers, which limits the development of CO2 emission reduction and conversion utilization. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite phase change material with photothermal synergistic catalytic performance, and its preparation method and application. The composite phase change material with photothermal synergistic catalytic performance provided by the present invention realizes efficient and rapid photothermal energy storage and conversion and photothermal synergistic catalytic effect, and has good economic efficiency.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a composite phase change material having photothermal synergistic catalytic performance, comprising the following steps:

[0008] A metal-organic framework material, a transition metal salt compound, and an organic solvent are mixed and chemically etched to obtain a transition metal-based hydrotalcite, wherein the transition metal element in the transition metal salt compound is of a different type from the transition metal element in the metal-organic framework material;

[0009] The transition metal-based hydrotalcite, the organic phase change material and the organic solvent are mixed and impregnated under vacuum conditions to obtain a composite phase change material with photothermal synergistic catalytic performance.

[0010] Preferably, the metal organic framework material includes ZIF-67 or ZIF-8.

[0011] Preferably, the transition metal salt compound includes nickel salt, copper salt, iron salt, zinc salt or cobalt salt.

[0012] Preferably, the organic phase change material includes one or more of polyols, fatty acids and paraffins.

[0013] Preferably, the mass ratio of the metal organic framework material to the transition metal salt compound is 1:2-4.

[0014] Preferably, the temperature of the chemical etching is 60-100° C., and the holding time is 5-240 minutes.

[0015] Preferably, the mass ratio of the transition metal-based hydrotalcite to the organic phase change material is 90:60-210.

[0016] Preferably, the immersion temperature is 50-90° C., and the insulation time is 0.5-12 h.

[0017] The present invention provides a composite phase change material with photothermal synergistic catalytic performance prepared by the preparation method described in the above technical solution, comprising a transition metal-based hydrotalcite and an organic phase change material supported on the surface and layer structure of the transition metal-based hydrotalcite.

[0018] The present invention provides the application of the composite phase change material with photothermal synergistic catalytic performance described in the above technical solution in photothermal energy storage materials or in photothermal synergistic catalytic CO2 conversion.

[0019] The present invention provides a method for preparing a composite phase change material with photothermal synergistic catalytic performance, comprising the following steps: mixing a metal organic framework material, a transition metal salt compound, and an organic solvent and chemically etching the mixture to obtain a transition metal-based hydrotalcite, wherein the transition metal element in the transition metal salt compound is different from the type of transition metal element in the metal organic framework material; mixing the transition metal-based hydrotalcite, an organic phase change material, and an organic solvent, and impregnating the mixture under vacuum conditions to obtain a composite phase change material with photothermal synergistic catalytic performance. The preparation method provided by the present invention uses a metal organic framework (MOFs) material as a template, chemically etching the transition metal salt to obtain a transition metal-based hydrotalcite LDHs with a uniform distribution of metal elements; then, the LDHs are used as a phase change carrier and composited with the organic phase change material. The composite phase change material with photothermal synergistic catalytic performance prepared by the present invention (referred to as LDHs composite phase change material) exhibits excellent photothermal effect under the illumination of a simulated sunlight xenon lamp, can effectively promote the adsorption and activation of carbon dioxide (CO2); at the same time, it can quickly increase the temperature around the active site, and can exhibit excellent photothermal synergistic catalytic CO2 conversion activity under low temperature conditions. The LDHs composite phase change material prepared by the present invention realizes efficient and rapid photothermal energy storage and conversion and photothermal synergistic catalytic application. The preparation method is simple and has good economic efficiency, providing a basis for photothermal catalytic synergistic research. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a SEM image of NiCo-LDH obtained in Example 1 of the present invention;

[0021] Figure 2 TEM image of NiCo-LDH obtained in Example 1 of the present invention;

[0022] Figure 3 This is an SEM image of the photothermal synergistic integrated catalytic material obtained in Example 1 of the present invention;

[0023] Figure 4 XRD patterns of NiCo-LDH and PEG-10000@LDH materials obtained in Example 1 of the present invention;

[0024] Figure 5 This is the DSC curve of the photothermal synergistic integrated catalytic material obtained in Example 1 of the present invention;

[0025] Figure 6 These are the photothermal conversion curves of NiCo-LDH and PEG-10000@LDH materials obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing a composite phase change material having photothermal synergistic catalytic performance, comprising the following steps:

[0027] A metal-organic framework material, a transition metal salt compound, and an organic solvent are mixed and chemically etched to obtain a transition metal-based hydrotalcite, wherein the transition metal element in the transition metal salt compound is of a different type from the transition metal element in the metal-organic framework material;

[0028] The transition metal-based hydrotalcite, the organic phase change material and the organic solvent are mixed and impregnated under vacuum conditions to obtain a composite phase change material with photothermal synergistic catalytic performance.

[0029] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0030] The present invention mixes a metal organic framework material, a transition metal salt compound and an organic solvent (hereinafter referred to as the first organic solvent) (hereinafter referred to as the first mixture) and performs chemical etching to obtain a transition metal-based hydrotalcite, wherein the transition metal element in the transition metal salt compound is of a different type from the transition metal element in the metal organic framework material.

[0031] In the present invention, the metal-organic framework material preferably includes ZIF-67 or ZIF-8, more preferably ZIF-67. In the present invention, the method for preparing the metal-organic framework material preferably includes the following steps: stirring and mixing a transition metal salt raw material, 2-methylimidazole (2MIM) and a second organic solvent, and allowing the resulting mixture to stand at room temperature to obtain the metal-organic framework material. In the present invention, the transition metal salt raw material is preferably Co(NO3)2 or Zn(NO3)2. The second organic solvent is preferably methanol. The room temperature standing time is preferably 24 hours.

[0032] The transition metal salt compound preferably includes a nickel salt, a copper salt, an iron salt, a zinc salt, or a cobalt salt, and more preferably a nickel salt, a copper salt, or an iron salt. The nickel salt is preferably Ni(NO3)2, the copper salt is preferably Cu(NO3)2, the iron salt is preferably Fe(NO3)3, the zinc salt is preferably Zn(NO3)2, and the cobalt salt is preferably Co(NO3)2. The weight ratio of the metal-organic framework material to the transition metal salt compound is preferably 1:2-4, more preferably 1:2.5.

[0033] The first organic solvent is preferably ethanol. The present invention has no special requirements for the amount of the first organic solvent used, as long as the chemical etching is carried out smoothly. The first mixing preferably includes the following steps: ultrasonically dispersing the metal-organic framework material in a portion of the first organic solvent to obtain a metal-organic framework material dispersion; dissolving the transition metal salt compound in the remaining first organic solvent to obtain a transition metal salt compound solution; and mixing the metal-organic framework material dispersion and the transition metal salt compound solution. The temperature of the chemical etching is preferably 60-100°C, more preferably 85°C, and the holding time is preferably 5-240 minutes, more preferably 10-15 minutes. After the etching reaction, an etching reaction liquid is obtained. The present invention preferably separates the etching reaction liquid into solid and liquid, and the obtained solid phase product is centrifuged and washed with ethanol to obtain a purified solid product; the purified solid product is dried to obtain the transition metal-based hydrotalcite. The drying temperature is preferably 60°C, and the drying time is preferably 24 hours.

[0034] In the present invention, the transition metal-based hydrotalcite preferably includes NiCo-LDH, FeCo-LDH, ZnCo-LDH or CuCo-LDH, more preferably NiCo-LDH or FeCo-LDH.

[0035] After obtaining the transition metal-based hydrotalcite, the present invention mixes the transition metal-based hydrotalcite, an organic phase change material and an organic solvent (hereinafter referred to as the third organic solvent) (hereinafter referred to as the second mixture), and impregnates them under vacuum conditions to obtain a composite phase change material with photothermal synergistic catalytic performance.

[0036] In the present invention, the transition metal-based hydrotalcite preferably includes NiCo-LDH, FeCo-LDH, ZnCo-LDH or CuCo-LDH, more preferably NiCo-LDH or FeCo-LDH.

[0037] The organic phase change material preferably includes one or more of polyols, fatty acids, and paraffins. The polyol preferably includes polyethylene glycol and / or stearyl alcohol. The fatty acid preferably includes one or more of capric acid, lauric acid, palmitic acid, and stearic acid. In the present invention, the organic phase change material is more preferably one or more of polyethylene glycol, stearic acid, and stearyl alcohol, with PEG-10000 being particularly preferred. The mass ratio of the transition metal-based hydrotalcite to the organic phase change material is preferably 90:60-210, more preferably 90:90-135, and even more preferably 90:135. The third organic solvent is preferably ethanol. The present invention has no specific requirements for the amount of ethanol used; it only requires that the impregnation proceeds smoothly. In the present invention, prior to the second mixing, the transition metal-based hydrotalcite is preferably subjected to a vacuum treatment, preferably at a temperature of 80°C and for a duration of 4 hours. The present invention preferably removes small molecules within the pores of the transition metal-based hydrotalcite through the vacuum treatment. The first mixing preferably includes: dissolving the organic phase change material in a third organic solvent to obtain an organic phase change material solution; and stirring and mixing the transition metal-based hydrotalcite and the organic phase change material solution. The stirring and mixing is preferably performed at a temperature of 60°C and for 2 hours. In the present invention, the immersion temperature is preferably 50-90°C, more preferably 80°C, and the holding time is preferably 0.5-12 hours, more preferably 2 hours.

[0038] The present invention provides a composite phase change material with photothermal synergistic catalytic performance prepared by the preparation method described in the above technical solution, comprising a transition metal-based hydrotalcite and an organic phase change material supported on the surface and layer structure of the transition metal-based hydrotalcite.

[0039] The composite phase change material with photothermal synergistic catalytic properties provided by the present invention includes a transition metal-based hydrotalcite. The transition metal-based hydrotalcite is preferably NiCo-LDH, FeCo-LDH, ZnCo-LDH, or CuCo-LDH, more preferably NiCo-LDH, FeCo-LDH, or CuCo-LDH, and most preferably NiCo-LDH or FeCo-LDH.

[0040] The composite phase change material with photothermal synergistic catalytic performance provided by the present invention includes an organic phase change material loaded on the surface and layer structure of the transition metal-based hydrotalcite. The organic phase change material preferably includes one or more of polyols, fatty acids and paraffins. The polyols preferably include polyethylene glycol and / or stearyl alcohol. The fatty acids preferably include one or more of capric acid, lauric acid, palmitic acid and stearic acid. In the present invention, the organic phase change material is more preferably one or more of polyethylene glycol, stearic acid and stearyl alcohol, and PEG-10000 is particularly preferred. The organic phase change material is loaded on the surface, layer structure and pore structure of the transition metal-based hydrotalcite.

[0041] In the present invention, the mass percentage of the organic phase change material to the mass percentage of the composite phase change material with photothermal synergistic catalytic performance is preferably 60%.

[0042] The present invention provides the use of the composite phase change material with photothermal synergistic catalytic performance described in the above technical solution in photothermal energy storage materials or in photothermal synergistic catalytic CO2 conversion. In the present invention, the CO2 conversion is preferably the catalytic generation of CO2 by CO2.

[0043] The application of the composite phase change material with photothermal synergistic catalytic performance provided by the present invention in the photothermal synergistic catalytic CO2 generation of CO includes the following steps: acetonitrile, triethanolamine, water and the composite phase change material with photothermal synergistic catalytic performance are mixed to obtain a reaction solution; CO2 is introduced into the reaction solution under the irradiation of sunlight or simulated sunlight xenon lamp to carry out a catalytic reaction. The volume ratio of the acetonitrile, triethanolamine and water is preferably 10:2:1. The ratio of the total volume of the acetonitrile, triethanolamine and water to the mass of the composite phase change material with photothermal synergistic catalytic performance is preferably 13mL:5mg. The flow rate of the CO2 introduced into the reaction solution is preferably 50mL / min. The catalytic reaction is carried out under water bath conditions, and the initial temperature of the reaction solution is preferably 5°C. The catalytic reaction is carried out under stirring conditions, the stirring speed is preferably 400rpm, and the stirring time is preferably 4h.

[0044] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] (1) 1742 mg of Co(NO3)2 was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent A; 3.2 g of 2-methylimidazole (2-MIM) was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent B; solvent A was added to solvent B and stirred evenly, the magnet was removed, and the mixture was allowed to stand at room temperature for 24 h to synthesize dodecahedral ZIF-67;

[0047] (2) 100 mg of ZIF-67 was dissolved in ethanol solution and ultrasonically dispersed to obtain solvent C; 250 mg of Ni(NO3)2 was dissolved in ethanol solution to obtain solvent D; solvent D was then poured into solvent C, reacted in an 85°C water bath for 15 min, cooled to room temperature, washed by centrifugation with ethanol, and dried at 60°C for 24 h to obtain NiCo-LDH with uniform distribution of metal elements; Figure 1 This is a SEM image of NiCo-LDH obtained in Example 1 of the present invention; Figure 2 TEM image of NiCo-LDH obtained in Example 1 of the present invention. Figure 1 and Figure 2 It can be seen that the NiCo-LDH prepared in this example has a porous structure.

[0048] (3) Take 90 mg of NiCo-LDH and evacuate it at 80 °C for 4 h to remove the small molecules in the pores; then disperse it in 20 mL of anhydrous ethanol solution containing 135 mg of polyethylene glycol (PEG-10000), stir it at 60 °C for 2 h, and place the mixture in a vacuum drying oven at 80 °C for 12 h to collect and obtain LDHs-based composite phase change material with photothermal catalytic performance. Figure 3 This is the SEM image of the photothermal integrated catalytic material obtained in Example 1 of the present invention. Figure 3 It can be seen that the catalytic material prepared in Example 1 has a stacked lamellar structure.

[0049] Figure 4 The XRD patterns of the NiCo-LDH carrier material and the PEG-10000@NiCo-LDH photothermal integrated material obtained in Example 1 of the present invention are shown in FIG. Figure 4 It can be seen that the photothermal integrated catalytic material prepared in Example 1 has two strong diffraction peaks at 2θ of 20-25°, which are attributed to PEG-10000, indicating that PEG-10000 is successfully loaded on NiCo-LDH.

[0050] Example 2

[0051] The difference from Example 1 is that the dosage of PEG-10000 is adjusted from 135 mg to 210 mg. The specific method is as follows:

[0052] (1) 1742 mg of Co(NO3)2 was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent A; 3.2 g of 2-methylimidazole (2-MIM) was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent B; solvent A was added to solvent B and stirred evenly, the magnet was removed, and the mixture was allowed to stand at room temperature for 24 h to synthesize dodecahedral ZIF-67;

[0053] (2) 100 mg of ZIF-67 was dissolved in ethanol solution and ultrasonically dispersed to obtain solvent C; 250 mg of Ni(NO3)2 was dissolved in ethanol solution to obtain solvent D; solvent D was then poured into solvent C, reacted in an 85°C water bath for 15 min, cooled to room temperature, washed by centrifugation with ethanol, and dried at 60°C for 24 h to obtain NiCo-LDH with uniform distribution of metal elements;

[0054] (3) Take 90 mg of NiCo-LDH and evacuate it at 80 °C for 4 h to remove the small molecules in the pores; then disperse it in 10 mL of anhydrous ethanol solution containing 210 mg of PEG-10000, stir it at 60 °C for 2 h, and place the mixture in a vacuum drying oven at 80 °C for 24 h to collect and obtain LDHs-based composite phase change material with photothermal conversion performance.

[0055] Example 3

[0056] The difference from Example 1 is that no phase change load is performed. The specific method is as follows:

[0057] (1) 1742 mg of Co(NO3)2 was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent A; 3.2 g of 2-methylimidazole (2-MIM) was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent B; solvent A was added to solvent B and stirred evenly, the magnet was removed, and the mixture was allowed to stand at room temperature for 24 h to synthesize dodecahedral ZIF-67;

[0058] (2) Dissolve 100 mg of ZIF-67 in ethanol solution and disperse it evenly by ultrasonication to obtain solvent C; take 250 mg of Ni(NO3)2 and dissolve it in ethanol solution to obtain solvent D; then pour solvent D into solvent C, react in an 85°C water bath for 15 minutes, cool to room temperature, wash with ethanol by centrifugation, and dry at 60°C for 24 hours to obtain NiCo-LDH with uniform distribution of metal elements.

[0059] Example 4

[0060] The difference from Example 1 is that Ni(NO3)2 is replaced by Cu(NO3)2. The specific method is as follows:

[0061] (1) 1742 mg of Co(NO3)2 was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent A; 3.2 g of 2-methylimidazole (2-MIM) was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent B; solvent A was added to solvent B and stirred evenly, the magnet was removed, and the mixture was allowed to stand at room temperature for 24 h to synthesize dodecahedral ZIF-67;

[0062] (2) 100 mg of ZIF-67 was dissolved in ethanol solution and ultrasonically dispersed to obtain solvent C; 250 mg of Cu(NO3)2 was dissolved in ethanol solution to obtain solvent D; solvent D was then poured into solvent C, reacted in an 85°C water bath for 15 min, cooled to room temperature, washed by centrifugation with ethanol, and dried at 60°C for 24 h to obtain CuCo-LDH with uniform distribution of metal elements;

[0063] (3) Take 90 mg of CuCo-LDH and evacuate at 80 °C for 4 h to remove small molecules in the pores; then disperse it in 20 mL of anhydrous ethanol solution containing 135 mg of polyethylene glycol (PEG-10000), stir it at 60 °C for 2 h, place the mixture in a vacuum drying oven at 80 °C, keep it warm for 12 h, and collect the LDHs-based composite phase change material with photothermal catalytic performance.

[0064] Example 5

[0065] The difference from Example 1 is that Ni(NO3)2 is replaced by Fe(NO3)3. The specific method is as follows:

[0066] (1) 1742 mg of Co(NO3)2 was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent A; 3.2 g of 2-methylimidazole (2-MIM) was dissolved in 200 mL of methanol and stirred for 5 min to form a homogeneous solution to obtain solvent B; solvent A was added to solvent B and stirred evenly, the magnet was removed, and the mixture was allowed to stand at room temperature for 24 h to synthesize dodecahedral ZIF-67;

[0067] (2) 100 mg of ZIF-67 was dissolved in ethanol solution and ultrasonically dispersed to obtain solvent C; 250 mg of Fe(NO3)3 was dissolved in ethanol solution to obtain solvent D; solvent D was then poured into solvent C, reacted in an 85°C water bath for 15 min, cooled to room temperature, washed by centrifugation with ethanol, and dried at 60°C for 24 h to obtain FeCo-LDH with uniform distribution of metal elements;

[0068] (3) Take 90 mg of FeCo-LDH and evacuate at 80 °C for 4 h to remove small molecules in the pores; then disperse it in 20 mL of anhydrous ethanol solution containing 135 mg of polyethylene glycol (PEG-10000), stir it at 60 °C for 2 h, and place the mixture in a vacuum drying oven at 80 °C for 12 h to collect and obtain LDHs-based composite phase change material with photothermal catalytic performance.

[0069] Performance characterization and results

[0070] (1) The LDHs-based composite phase change material with photothermal conversion performance prepared in Example 1 was tested using a DSC tester ( Figure 4 The endothermic and exothermic properties of PEG-10000@NiCo-LDH) are shown in the DSC curve. Figure 5 As shown. Figure 5It can be seen that the DSC melting curve and solidification curve of the composite phase change material prepared in Example 1 are compared with PEG-10000. The LDHs carrier material reduces the supercooling of PEG-10000, indicating that the addition of LDHs promotes the occurrence of the phase change process. At the same time, the melting enthalpy of the LDHs-based composite phase change material prepared in Example 1 is 92.85 J / g, and the solidification enthalpy is 93.17 J / g, indicating that the LDHs-based composite phase change material prepared in Example 1 has excellent phase change energy storage capacity. The composite phase change materials prepared in Example 2, Example 4, and Example 5 have similar test results to the phase change material in Example 1.

[0071] (2) Using a xenon lamp to simulate sunlight, the photothermal conversion performance of the material obtained in Example 1 was tested. The photothermal conversion curve is shown in FIG. Figure 6 As shown. The composite phase change material prepared in Example 1 exhibits excellent light-to-heat conversion capabilities, with a distinct temperature rise and fall platform, reaching ~75°C after 600s of illumination. However, the NiCo-LDH in Example 1, which was not loaded with the phase change material PEG-10000, showed no temperature rise and fall platform in its light-to-heat conversion curve. The composite phase change materials prepared in Examples 2, 4, and 5 showed similar test results to the phase change material in Example 1.

[0072] (3) The catalytic CO2 conversion performance of the materials prepared in Examples 1 to 5 was tested using a liquid-solid test system under illumination of a simulated sunlight xenon lamp. Acetonitrile: triethanolamine: H2O (10 mL: 2 mL: 1 mL) was added to a reaction vessel, and 5 mg of the catalytic materials prepared in Examples 1 to 5 were added to the above solutions respectively. CO2 was introduced into the solution at a rate of 50 mL / min. The mixture was stirred at 400 rpm in a cold water bath at 5°C for 30 min, and the CO yield was calculated.

[0073] The catalytic results showed that the catalytic material prepared in Example 1 exhibited significant photothermal synergistic catalytic performance in converting CO2 into CO. When the illumination was irradiated for 30 min, the product generation rate was 2824.5 μmol·g -1 ·h -1 The product CO generation rates of Examples 2, 3, 4, and 5 were 943 μmol·g -1 ·h -1 、1014μmol·g -1 ·h -1 、2617μmol·g -1 ·h -1 、3464μmol·g -1 ·h -1The lower CO yield in Example 2 is due to the use of an excess of PEG-10000 compared to Example 1. This excess PEG-10000 covers some of the catalytic active sites, resulting in poor photothermal synergistic catalytic performance. Examples 4 and 5 demonstrate that this reaction can be extended to other hydrotalcite material systems, all of which exhibit excellent photothermal synergistic catalytic performance.

[0074] The above test results show that: under the illumination of simulated sunlight xenon lamp, the transition metal-based LDH composite phase change material prepared by the embodiment of the present invention exhibits an excellent photothermal effect, which can effectively promote the adsorption and activation of CO2; at the same time, the photothermal effect can also quickly increase the temperature around the active site, promote the interaction between reaction substrate molecules such as CO2 and the active sites on the catalyst surface, and can exhibit excellent photo-thermal synergistic catalytic CO2 conversion activity under low temperature conditions. The transition metal-based LDH composite phase change material with photothermal synergistic catalytic performance provided by the present invention realizes efficient and rapid photothermal energy storage and conversion and photothermal synergistic catalysis, has a simple preparation method, and has good economic efficiency, providing a basis for photothermal synergistic catalysis research.

[0075] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. Application of a composite phase change material with photothermal synergistic catalytic performance in photothermal synergistic catalytic CO2 conversion, characterized in that: The composite phase change material with photothermal synergistic catalytic performance comprises a transition metal-based hydrotalcite and an organic phase change material supported on the surface and layer structure of the transition metal-based hydrotalcite; The preparation method of the composite phase change material with photothermal synergistic catalytic performance comprises the following steps: A metal-organic framework material, a transition metal salt compound, and an organic solvent are mixed and chemically etched to obtain a transition metal-based hydrotalcite, wherein the transition metal element in the transition metal salt compound is of a different type from the transition metal element in the metal-organic framework material, and the metal-organic framework material includes ZIF-67 or ZIF-8; The transition metal-based hydrotalcite, organic phase change material and organic solvent are mixed and impregnated under vacuum conditions to obtain a composite phase change material with photothermal synergistic catalytic performance. The mass ratio of the transition metal-based hydrotalcite to the organic phase change material is 90:

135.

2. The use according to claim 1, characterized in that The transition metal salt compound includes nickel salt, copper salt, iron salt, zinc salt or cobalt salt.

3. The use according to claim 1, characterized in that The organic phase change material includes one or more of polyols, fatty acids and paraffins.

4. The use according to any one of claims 1 to 3, wherein the mass ratio of the metal organic framework material to the transition metal salt compound is 1:2-4.

5. The use according to claim 1, characterized in that The chemical etching temperature is 60-100° C., and the holding time is 5-240 min.

6. The use according to claim 1, characterized in that The immersion temperature is 50-90° C., and the holding time is 0.5-12 h.

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