Infrared radiation heat dissipation composite material and preparation method, coating and application thereof

Abstract

The invention discloses an infrared radiation heat dissipation composite material as well as a preparation method, a coating and application thereof. The preparation method of the infrared radiation heat dissipation composite material comprises the following steps: firstly, dispersing soluble rare earth metal salt and graphene oxide in deionized water, adjusting the pH value, heating, and carrying out a hydrothermal reaction; and washing and drying the reaction product, and calcining in a protective atmosphere. A hydrothermal in-situ loading method is adopted, carrier absorption of reduced graphene oxide is promoted by utilizing a rich electronic structure of the synthesized rare-earth metal oxide, and the rare-earth metal oxide is uniformly loaded on the surface of the reduced graphene oxide due to a porous structure constructed between the reduced graphene oxide, so that the surface of the reduced graphene oxide is uniformly loaded on the surface of the rare-earth metal oxide. Incident light is subjected to multiple times of diffuse reflection and absorption, and the emissivity is promoted to be improved. The prepared composite material is added into a high-molecular polymer to form an infrared radiation heat dissipation coating, and the infrared radiation heat dissipation coating not only has full-wave-band high emissivity, but also has high heat conductivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and specifically relates to an infrared radiation heat dissipation composite material and a preparation method, a coating and an application thereof, and in particular relates to a rare earth metal oxide@reduced graphene oxide infrared radiation heat dissipation composite material, an infrared radiation heat dissipation coating enhanced by the composite material, and a preparation method and an application thereof. Background Art

[0002] As electronic devices develop towards miniaturization and high integration, their heat generation power and heat flux density continue to increase. Excessive temperature of electronic devices will not only seriously affect the performance of electronic devices, but also greatly shorten the service life of electronic devices. Traditional heat dissipation methods based on heat conduction and heat convection mechanisms are difficult to apply to electronic devices with limited space due to their huge volume. Passive radiation heat dissipation technology achieves heat dissipation by emitting heat into low-temperature space or low-temperature environment in the form of thermal radiation. It does not require any additional energy input and occupies a small volume. Passive radiation heat dissipation provides a new idea for the thermal management of electronic devices.

[0003] With the development of nano-optics, scholars have developed a series of materials with efficient radiation heat dissipation performance, such as photonic structures and metamaterials. The spectral properties of most of these materials are selective emission in the atmospheric window, that is, high emission in the 8-13μm band and high reflection in the other bands. This spectral design can achieve daytime sub-ambient temperature cooling. However, when electronic devices heat up, their temperature is generally higher than the temperature of the atmosphere and the surrounding environment. The radiation heat dissipation coating selectively emitted by the atmospheric window only radiates energy outward in the 8-13μm band, making it difficult to achieve efficient radiation heat dissipation of electronic devices. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes an infrared radiation heat dissipation composite material and its preparation method, coating and application, wherein the coating contains an infrared radiation heat dissipation composite material, which has high infrared emissivity in the 2.5-15μm band, providing a new solution for heat dissipation of electronic devices.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing an infrared radiation heat dissipation composite material, comprising the following steps:

[0006] (1) dispersing a soluble rare earth metal salt and graphene oxide in deionized water, adjusting the pH value, and performing a hydrothermal reaction;

[0007] (2) The reaction product obtained in step (1) is washed and dried, and then calcined under a protective atmosphere to obtain the infrared radiation composite material.

[0008] Specifically, the present invention uses soluble rare earth metal salts and graphene oxide as main raw materials, adopts a hydrothermal in-situ loading method, and makes the synthesized rare earth metal oxide particles and reduced graphene oxide dispersed evenly, and the rare earth metal oxide particles are rod-shaped particles, and the rod-shaped particles help to construct a porous structure in the reduced graphene oxide, so that the incident light can be diffusely reflected and absorbed multiple times, promoting the improvement of emissivity. At the same time, the rich electronic structure of the rare earth metal oxide is conducive to promoting the carrier absorption of the reduced graphene oxide, and the porous structure constructed by the rare earth metal oxide between the reduced graphene oxide makes the rare earth metal oxide uniformly loaded on the surface of the reduced graphene oxide, avoiding the agglomeration phenomenon between the particles, thereby further improving the emissivity of the composite material, and then improving the infrared radiation heat dissipation effect.

[0009] Preferably, in step (1), the soluble rare earth metal salt is selected from at least one of europium nitrate, cerium nitrate, yttrium nitrate, samarium nitrate, lanthanum nitrate, neodymium nitrate, praseodymium nitrate, europium chloride, cerium chloride, yttrium chloride, samarium chloride, lanthanum chloride, neodymium chloride and praseodymium chloride.

[0010] Preferably, in step (1), the mass ratio of the soluble rare earth metal salt to graphene oxide is (2-20):1.

[0011] Preferably, in step (1), the pH value is adjusted by ammonia water, and the adjusted pH value is 9-10.

[0012] Preferably, in step (1), the temperature of the hydrothermal reaction is 120-180°C.

[0013] Preferably, in step (1), the hydrothermal reaction time is 6-24 hours.

[0014] Preferably, in step (2), the washing is performed by alternating deionized water and ethanol for 2-4 times to remove residual soluble rare earth metal salts and graphene oxide.

[0015] Preferably, in step (2), the protective atmosphere is an argon atmosphere.

[0016] Preferably, in step (2), the calcination temperature is 400-800°C.

[0017] Preferably, in step (2), the calcination time is 2-6 hours.

[0018] The second aspect of the present invention provides an infrared radiation heat dissipation composite material, which is prepared by the above-mentioned preparation method. The infrared radiation heat dissipation composite material includes rare earth metal oxide and reduced graphene oxide, and the rare earth metal oxide is uniformly loaded on the surface of the reduced graphene oxide.

[0019] The study found that rare earth metal oxides have a rich electronic structure and reduced graphene oxide has excellent thermal conductivity. Loading rare earth metal oxides onto the surface of reduced graphene oxide and the interaction between the two will effectively improve the emissivity and thermal conductivity of the composite material.

[0020] Preferably, the mass ratio of the rare earth metal oxide to the reduced graphene oxide is (2.5-10):1.

[0021] Further preferably, the mass ratio of the rare earth metal oxide to the reduced graphene oxide is (5-10):1.

[0022] A third aspect of the present invention provides an infrared radiation heat dissipation coating, the raw material components of which include the above-mentioned infrared radiation heat dissipation composite material, a high molecular polymer and an additive, wherein the additive includes a curing agent or a coupling agent.

[0023] Preferably, the mass ratio of the infrared radiation heat dissipation composite material, the high molecular polymer and the additive is 1:(5-20):(0.5-2).

[0024] Preferably, the high molecular polymer is selected from at least one of polyvinylidene fluoride, polydimethylsiloxane (PDMS), polyimide and polymethyl methacrylate.

[0025] Specifically, these polymers all have a certain infrared radiation capability. The addition of rare earth metal oxide@reduced graphene oxide composite materials makes the polymer structure more complex, which is conducive to improving the spectral emissivity of the polymer. At the same time, since reduced graphene oxide has high thermal conductivity, the rod-shaped particles of rare earth metal oxide build a "thermal bridge" in reduced graphene oxide, thereby further improving the thermal conductivity of the coating, thereby comprehensively improving the heat dissipation performance of the coating.

[0026] Preferably, the coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane.

[0027] Preferably, the curing agent is selected from at least one of methyltriethoxysilane and methyltripropoxysilane.

[0028] A fourth aspect of the present invention provides a method for preparing an infrared radiation heat dissipation coating, comprising the following steps:

[0029] The infrared radiation heat dissipation composite material, high molecular polymer and additives are mixed into slurry, and then the slurry is poured into a mold, and the infrared radiation heat dissipation coating is formed through film forming and drying.

[0030] Preferably, the infrared radiation heat dissipation coating has a thickness of 400-600 μm.

[0031] Preferably, the film forming method is a blade coating method.

[0032] Preferably, the drying is performed at 70-90° C. for 1-3 hours.

[0033] A fifth aspect of the present invention provides the use of the above-mentioned infrared radiation heat dissipation coating in electronic devices, LED lighting, photovoltaic modules or chips.

[0034] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages:

[0035] (1) The present invention uses soluble rare earth metal salts and graphene oxide as main raw materials, adopts a hydrothermal in-situ loading method, utilizes the rich electronic structure of the synthesized rare earth metal oxide to promote the carrier absorption of the reduced graphene oxide, and the porous structure constructed by the rare earth metal oxide between the reduced graphene oxide makes the rare earth metal oxide uniformly loaded on the surface of the reduced graphene oxide, avoiding the agglomeration phenomenon between particles; and utilizes the porous structure constructed by the rod-shaped rare earth metal oxide particles in the reduced graphene oxide to make the incident light undergo multiple diffuse reflections and absorptions, thereby promoting the improvement of the emissivity.

[0036] (2) The infrared radiation heat dissipation composite material prepared by the present invention includes rare earth metal oxides and reduced graphene oxide, and the rare earth metal oxides are uniformly loaded on the surface of the reduced graphene oxide. The rare earth metal oxides are used to improve the spectral properties of the reduced graphene oxide, so that it has a higher emissivity in the entire band.

[0037] (3) The rare earth metal oxide@reduced graphene oxide composite material prepared by the present invention is added to a high molecular polymer to form an infrared radiation heat dissipation coating, which not only has a high emissivity in the entire band, but also has a high thermal conductivity. At an input power of 5 W, a cooling temperature difference of more than 12°C can be obtained, which has great application prospects in the field of electronics industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a microscopic morphology of the infrared radiation heat dissipation composite material prepared in Example 1;

[0039] Figure 2 This is a microscopic morphology of the infrared radiation heat dissipation coating prepared in Example 1;

[0040] Figure 3 This is a microscopic morphology of the infrared radiation heat dissipation coating prepared in Example 2;

[0041] Figure 4 This is a microscopic morphology of the infrared radiation heat dissipation coating prepared in Example 3;

[0042] Figure 5Spectral emissivity diagram of the infrared radiation heat dissipation composite material prepared in Example 1 and Comparative Example 1;

[0043] Figure 6 Spectral emissivity diagram of the infrared radiation heat dissipation coating prepared in Examples 1-3;

[0044] Figure 7 This is a temperature change diagram of the infrared radiation heat dissipation coating prepared in Examples 1-3 when attached to an electronic device indoors. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with the examples, so that the technical personnel of the relevant technical field can understand the present invention. It is necessary to point out here that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. The non-essential improvements and adjustments made to the present invention by the skilled person in the relevant field according to the above invention content should still belong to the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods that are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0046] Example 1

[0047] A method for preparing an infrared radiation heat dissipation composite material comprises the following steps:

[0048] Weigh 0.1g of graphene oxide, dissolve it in 50mL of deionized water, and disperse it ultrasonically; weigh 2.544g of Y(NO3)3·6H2O, dissolve it in 20mL of deionized water; mix the two solutions and disperse them evenly by ultrasonic, then add ammonia water to adjust the pH to 10, continue stirring for 1 hour, place it in a 100mL reactor and react at 180℃ for 12 hours. During the reaction, graphene oxide is reduced to form reduced graphene oxide rGO. After the reaction, the reaction product is washed alternately with deionized water and ethanol for 3 times, and then placed in a blast drying oven at 60℃ for 12 hours. The dried product is ground and placed in a tube furnace and calcined at 600℃ for 3 hours under argon atmosphere. During the calcination process, Y3(OH)3 is dehydrated to Y2O3, and finally a Y2O3@rGO infrared radiation heat dissipation composite material is obtained, wherein the mass ratio of Y2O3 to rGO is 7.5:1.

[0049] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0050] Weigh 2.85g of PDMS and 0.285g of curing agent methyltriethoxysilane in a beaker, stir evenly, then weigh 0.15g of Y2O3@rGO prepared in this example and add it to PDMS. Use a glass rod to stir repeatedly under ultrasonic action until PDMS, curing agent, and Y2O3@rGO are evenly dispersed to form a slurry. Apply the slurry to a 40×40mm polytetrafluoroethylene mold, use a scraper to scrape out the excess slurry, place it in a blast drying oven and dry it at 80°C for 2 hours, and after demolding, obtain the Y2O3@rGO@PDMS infrared radiation heat dissipation coating.

[0051] Example 2

[0052] A method for preparing an infrared radiation heat dissipation composite material comprises the following steps:

[0053] Weigh 0.1g of graphene oxide, dissolve it in 50mL of deionized water, and disperse it ultrasonically; weigh 2.534g of Eu(NO3)3·6H2O, dissolve it in 20mL of deionized water; mix the two solutions and disperse them evenly by ultrasonic, then add ammonia water to adjust the pH to 10, continue stirring for 1 hour, place it in a 100mL reactor and react at 180℃ for 12 hours. During the reaction, graphene oxide is reduced to form reduced graphene oxide rGO. After the reaction, the reaction product is washed alternately with deionized water and ethanol for 3 times, and then placed in a blast drying oven at 60℃ for 12 hours. After grinding, the dried product is placed in a tube furnace and calcined at 600℃ for 3 hours under argon atmosphere. During the calcination process, Eu3(OH)3 is dehydrated to Eu2O3, and finally Eu2O3@rGO infrared radiation heat dissipation composite material is obtained, wherein: the mass ratio of Eu2O3 to rGO is 10:1.

[0054] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0055] Weigh 2.85g of PDMS and 0.285g of curing agent methyltriethoxysilane in a beaker, stir evenly, then weigh 0.15g of Eu2O3@rGO prepared in this example and add it to PDMS. Use a glass rod to stir repeatedly under ultrasonic action until PDMS, curing agent, and Eu2O3@rGO are evenly dispersed to form a slurry. Apply the slurry to a 40×40mm polytetrafluoroethylene mold, use a scraper to scrape out the excess slurry, place it in a blast drying oven and dry it at 80°C for 2 hours, and after demolding, obtain the Eu2O3@rGO@PDMS infrared radiation heat dissipation coating.

[0056] Example 3

[0057] A method for preparing an infrared radiation heat dissipation composite material comprises the following steps:

[0058] Weigh 0.1g of graphene oxide, dissolve it in 50mL of deionized water, and disperse it ultrasonically; weigh 1.892g of Ce(NO3)3·6H2O, dissolve it in 20mL of deionized water; mix the two solutions and disperse them evenly by ultrasonic, then add ammonia water to adjust the pH to 10, continue stirring for 1 hour, place it in a 100mL reactor and react at 180℃ for 12 hours. During the reaction, graphene oxide is reduced to form reduced graphene oxide rGO. After the reaction, the reaction product is washed alternately with deionized water and ethanol for 3 times, and then placed in a blast drying oven at 60℃ for 12 hours. The dried product is ground and placed in a tube furnace and calcined at 600℃ for 3h under argon atmosphere. During the calcination process, Ce(OH)4 is dehydrated to CeO2, and finally a CeO2@rGO infrared radiation heat dissipation composite material is obtained, wherein: the mass ratio of CeO2 to rGO is 7.5:1.

[0059] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0060] Weigh 2.85g PDMS and 0.285g curing agent methyltriethoxysilane in a beaker, stir evenly, then weigh 0.15g CeO2@rGO prepared in this example and add it to PDMS. Use a glass rod to stir repeatedly under ultrasonic action until PDMS, curing agent, and CeO2@rGO are evenly dispersed to form a slurry. Apply the slurry to a 40×40mm polytetrafluoroethylene mold, use a scraper to scrape out the excess slurry, place it in a blast drying oven and dry it at 80°C for 2 hours, and after demolding, obtain the CeO2@rGO@PDMS infrared radiation heat dissipation coating.

[0061] Embodiment 4-6

[0062] The only difference between Examples 4-6 and Example 1 is that the mass ratios of Y2O3 to rGO are different, which are 2.5:1, 5:1 and 10:1 respectively.

[0063] Embodiment 7-9

[0064] The only difference between Examples 7-9 and Example 2 is that the mass ratios of Eu2O3 to rGO are different, which are 2.5:1, 5:1 and 7.5:1, respectively.

[0065] Examples 10-12

[0066] The only difference between Examples 10-12 and Example 1 is that the mass ratios of CeO2 to rGO are different, which are 2.5:1, 5:1 and 10:1, respectively.

[0067] Comparative Example 1

[0068] The difference between Comparative Example 1 and Example 1 is that the infrared radiation heat dissipation material of Comparative Example 1 is a single rGO, and its preparation method comprises the following steps:

[0069] Weigh 0.1g of graphene oxide, dissolve it in 50mL of deionized water, disperse it ultrasonically, then add ammonia water to adjust the pH to 10, continue stirring for 1 hour, place it in a 100mL reactor and react at 180°C for 12 hours. During the reaction, graphene oxide is reduced to form reduced graphene oxide rGO. After the reaction, the reaction product is washed alternately with deionized water and ethanol for 3 times, and then placed in a blast drying oven at 60°C for 12 hours to finally obtain rGO infrared radiation heat dissipation material.

[0070] Comparative Example 2

[0071] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0072] Weigh 2.85g PDMS and 0.285g curing agent methyltriethoxysilane in a beaker, stir evenly, then weigh 0.15g Y2O3 and graphene (mass ratio is 7.5:1) and disperse evenly to form a slurry. Apply the slurry to a 40×40mm polytetrafluoroethylene mold, use a scraper to scrape off the excess slurry, place it in a blast drying oven at 80℃ for 2 hours, and obtain an infrared radiation heat dissipation coating after demolding.

[0073] Performance Testing

[0074] 1. Microstructure

[0075] Figure 1 This is a microscopic morphology of the Y2O3@rGO infrared radiation heat dissipation composite material prepared in Example 1. Figure 1 It can be seen that the rod-shaped Y2O3 is evenly dispersed on the surface of the rGO sheets, and Y2O3 forms a porous structure between the rGO sheets.

[0076] Figure 2-4 They are microscopic morphology images of the infrared radiation heat dissipation coatings prepared in Examples 1-3, Figure 2-4 It can be seen that the surfaces of the coatings prepared in Examples 1-3 are relatively uniform and smooth, and have no obvious defects such as holes and cracks.

[0077] 2. Spectral emission

[0078] The infrared radiation heat dissipation materials prepared in Example 1 and Comparative Example 1 were measured using FTIR equipped with a gold integrator accessory. Since the powder was black and the apparent transmittance was 0, the emissivity was calculated by measuring the reflectivity. The results are as follows: Figure 5 As shown (the horizontal axis Wavelenth represents the wavelength, and the vertical axis Emissivity represents the emissivity). Figure 5It can be seen that compared with pure rGO, the loading of Y2O3 significantly improves the emissivity in all bands.

[0079] Figure 6 The spectral emissivity diagram of the infrared radiation heat dissipation coating prepared in Examples 1-3, the emissivity is calculated by measuring the reflectivity and transmittance (emissivity = 1-transmittance-reflectivity), from Figure 6 It can be seen that the emissivity of the three infrared radiation heat dissipation composite materials is at a high level. In the 2.5-7.5μm band, Eu2O3@rGO has the highest emissivity, and there is no obvious difference among the three in the 7.5-15μm band.

[0080] The same method was used to measure the emissivity of the infrared radiation heat dissipation composite materials prepared in Examples 1-12 and Comparative Examples 1-2. The results are shown in Table 1.

[0081] Table 1:

[0082] Infrared radiation heat dissipation material Mass ratio of rare earth metal oxides to rGO Infrared emissivity (2.5-15μm range) Example 1 <![CDATA[Y2O3:rGO=7.5:1]]> 0.979 Example 2 <![CDATA[Eu2O3:rGO=10:1]]> 0.959 Example 3 <![CDATA[CeO2:rGO=7.5:1]]> 0.968 Example 4 <![CDATA[Y2O3:rGO=2.5:1]]> 0.923 Example 5 <![CDATA[Y2O3:rGO=5:1]]> 0.948 Example 6 <![CDATA[Y2O3:rGO=10:1]]> 0.933 Example 7 <![CDATA[Eu2O3:rGO=2.5:1]]> 0.942 Example 8 <![CDATA[Eu2O3:rGO=5:1]]> 0.957 Example 9 <![CDATA[Eu2O3:rGO=7.5:1]]> 0.953 Example 10 <![CDATA[CeO2:rGO=2.5:1]]> 0.935 Embodiment 11 <![CDATA[CeO2:rGO=5:1]]> 0.963 Example 12 <![CDATA[CeO2:rGO=10:1]]> 0.951 Comparative Example 1 R 0.916 Comparative Example 2 <![CDATA[Y2O3: rGO = 7.5: 1 (direct mixing)]]> 0.956

[0083] As can be seen from Table 1, the average emissivity of different infrared radiation heat dissipation composite materials prepared in Examples 1-12 in the 2.5-15μm band is all above 0.9, among which Example 1 has the highest, reaching 0.979. The loading of rare earth oxide particles can effectively improve the emissivity of reduced graphene oxide, and the in-situ loading by the hydrothermal method has a greater improvement than the direct mixing method. Compared with Example 1, Comparative Examples 1-2 use a single rGO or a direct mixture of Y2O3 and rGO, and their average emissivity in the 2.5-15μm band is significantly lower than that of Example 1.

[0084] 3. Heat dissipation performance

[0085] After 1.5 hours at an input power of 5 W, the surface temperature of the copper plate not covered with the infrared radiation heat dissipation coating was 99.4°C. Then, the coatings prepared in Examples 1-3 and Comparative Examples 1-2 were respectively covered on electronic heating components with a surface area of ​​40×40 mm. The stable temperature of the coating was obtained at the same power and power-on time, and the heat dissipation temperature difference was calculated. The results are shown in Tables 2 and 3. Figure 7 shown.

[0086] Table 2:

[0087]

[0088]

[0089] It can be seen from Table 2 that the infrared radiation heat dissipation coatings prepared in the present invention all have good heat dissipation effects, and the heat dissipation temperature difference is above 11°C. Among them, the Y2O3@rGO@PDMS infrared radiation heat dissipation coating prepared in Example 1 has the best heat dissipation effect, and the heat dissipation temperature difference reaches 12.3°C (see Figure 7 , Figure 7 The horizontal axis Time represents time, and the vertical axis Temperature represents temperature. Compared with Example 1, in Comparative Examples 1-2, the heat dissipation effect is significantly reduced compared with Example 1 due to the use of single rGO or direct mixing of Y2O3 and rGO.

[0090] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, without having to go through creative labor. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the protection scope of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should belong to the protection scope of the present invention.

Claims

1. A method for preparing an infrared radiation heat dissipation composite material, characterized in that: The following steps are involved: (1) dispersing a soluble rare earth metal salt and graphene oxide in deionized water, adjusting the pH value, and performing a hydrothermal reaction; (2) The reaction product obtained in step (1) is washed and dried, and then calcined under a protective atmosphere to obtain the infrared radiation heat dissipation composite material.

2. The method for preparing the infrared radiation heat dissipation composite material according to claim 1, characterized in that: In step (1), the soluble rare earth metal salt is at least one selected from the group consisting of europium nitrate, cerium nitrate, yttrium nitrate, samarium nitrate, lanthanum nitrate, neodymium nitrate, praseodymium nitrate, europium chloride, cerium chloride, yttrium chloride, samarium chloride, lanthanum chloride, neodymium chloride, and praseodymium chloride; And / or, the mass ratio of the soluble rare earth metal salt to graphene oxide is (2-20):

1.

3. The method for preparing the infrared radiation heat dissipation composite material according to claim 1, characterized in that: In step (1), the pH value is adjusted by ammonia water, and the adjusted pH value is 9-10.

4. The method for preparing the infrared radiation heat dissipation composite material according to claim 1, characterized in that: In step (1), the temperature of the hydrothermal reaction is 120-180° C.; and / or the time of the hydrothermal reaction is 6-24 hours.

5. The method for preparing the infrared radiation heat dissipation composite material according to claim 1, characterized in that: In step (2), the calcination temperature is 400-800° C.; and / or the calcination time is 2-6 hours.

6. An infrared radiation heat dissipation composite material, characterized in that: The infrared radiation heat dissipation composite material is prepared by the preparation method according to any one of claims 1 to 5, comprising rare earth metal oxide and reduced graphene oxide, and the rare earth metal oxide is uniformly loaded on the surface of the reduced graphene oxide.

7. The infrared radiation heat dissipation composite material according to claim 6, characterized in that: The mass ratio of the rare earth metal oxide to the reduced graphene oxide is (2.5-10):

1.

8. An infrared radiation heat dissipation coating, characterized in that: The raw material components include the infrared radiation heat dissipation composite material according to claim 6 or 7, a high molecular polymer and an additive, wherein the additive includes a curing agent or a coupling agent.

9. The infrared radiation heat dissipation coating according to claim 8, characterized in that: The mass ratio of the infrared radiation heat dissipation composite material, the high molecular polymer and the additive is 1:(5-20):(0.5-2); And / or, the high molecular polymer is at least one selected from polyvinylidene fluoride, polydimethylsiloxane, polyimide, and polymethyl methacrylate; And / or, the coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane; And / or, the curing agent is selected from at least one of methyltriethoxysilane and methyltripropoxysilane.

10. Use of the infrared radiation heat dissipation coating according to claim 8 or 9 in electronic devices, LED lighting, photovoltaic modules or chips.

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