Preparation method and application of TiO2@LM shell-core photothermal material

Abstract

The application discloses a preparation method of TiO2@LM shell-core photothermal material and application thereof, and belongs to the technical field of photothermal conversion materials. The preparation method comprises the following steps: (1) preparation of a liquid metal micro-nanoparticle dispersion liquid; (2) surface modification of the liquid metal particles; (3) in-situ coating of a titanium dioxide shell layer; and (4) calcination and purification. The TiO2@LM shell-core photothermal material takes liquid metal as a core and titanium dioxide as a shell, solves inherent defects of single photothermal material through shell-core structure design of a composite material, realizes full-spectrum efficient light absorption and photothermal conversion, and makes the prepared photothermal particles capable of being uniformly dispersed in a polymer matrix through surface modification of a coupling agent. Meanwhile, the shell-core photothermal particles are applied to the fields of photothermal fibers, photothermal films and photothermal shape memory materials, a photothermal conversion product with fast heating rate and large heating amplitude is prepared, and the application range of the efficient photothermal conversion material is widened.

Description

Technical Field

[0001] This invention relates to the field of photothermal conversion materials technology, specifically to a method for preparing a TiO2@LM core-shell photothermal material and its application. Background Technology

[0002] Photothermal conversion materials are core functional materials for the efficient utilization of solar energy, widely used in photothermal textiles, seawater desalination, photothermal catalysis, and smart energy storage. Titanium dioxide (TiO2), a commonly used inorganic photothermal material, has advantages such as non-toxicity, high chemical stability, and low cost. However, its band gap is as wide as 3.2 eV, absorbing only ultraviolet light (λ < 400 nm), with absorbance < 0.2 in the visible-near-infrared region. It also exhibits a fast photogenerated electron-hole recombination rate, resulting in a photothermal heating range of only 5-8℃ for pure TiO2, leading to low photothermal conversion efficiency. Liquid metal (LM) possesses a high free electron density and generates localized surface plasmon resonance (LSPR) under near-infrared light excitation. It efficiently converts light energy into heat energy through non-radiative relaxation, demonstrating excellent photothermal potential. However, the gallium oxide shell formed by the oxidation of liquid metal itself has low mechanical strength and is prone to cracking during processing or use, leading to leakage and reducing its durability. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide a method for preparing TiO2@LM core-shell photothermal materials and their applications, thereby solving the problems of narrow light absorption range, easy recombination of photogenerated carriers, low photothermal conversion efficiency when used alone, and easy agglomeration and leakage of liquid metals. At the same time, it overcomes the difficulties of poor photothermal performance of photothermal conversion fibers, membranes, and fabrics.

[0004] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing TiO2@LM core-shell photothermal material is provided, comprising the following steps: (1) Preparation of liquid metal micro / nanoparticle dispersion: Liquid metal is added to anhydrous ethanol or acetone and ultrasonically dispersed to obtain liquid metal micro / nanoparticle dispersion; (2) Surface modification of liquid metal particles: Ammonia water was added to the liquid metal micro-nano particle dispersion in step (1) and ultrasonic dispersion was performed for the first time. Then hexadecylamine was added and ultrasonic dispersion was performed for the second time to obtain the modified dispersion. (3) In-situ coating of titanium dioxide shell: Cool the dispersion modified in step (2) to 0~5℃, add isopropyl titanate dropwise under stirring to react, then collect the precipitate by centrifugation, wash the precipitate with deionized water and anhydrous ethanol, and freeze-dry to obtain core-shell precursor powder. (4) Calcination purification: The core-shell precursor powder from step (3) is calcined in air at 350-500°C for 1-3 hours. The resulting product is then cooled to room temperature and calcined in an inert atmosphere at 600-800°C for 0.5-2 hours. The resulting product is then cooled to room temperature to obtain the product.

[0005] Furthermore, the liquid metal in step (1) is a gallium-based liquid metal.

[0006] Furthermore, gallium-based liquid metals include at least one of gallium indium tin alloy, gallium indium alloy, gallium tin alloy, and gallium zinc alloy.

[0007] Furthermore, in step (2), the volume ratio of the liquid metal micro / nano particle dispersion to ammonia is 30-70:1; the ratio of hexadecylamine to the liquid metal micro / nano particle dispersion is 4-12:1 (w / v).

[0008] Furthermore, in step (3), the volume ratio of the dispersion to isopropyl titanate is 60~140:1.

[0009] Furthermore, the heating rate of the heat preservation calcination in step (4) is 5~15℃ / min.

[0010] This invention provides a TiO2@LM core-shell photothermal material prepared by the above-described method.

[0011] This invention provides an application of the above-mentioned TiO2@LM core-shell photothermal material in the preparation of photothermal conversion materials.

[0012] This invention provides a photothermal conversion material, including the above-mentioned TiO2@LM core-shell photothermal material.

[0013] Furthermore, the photothermal conversion material is one of the following: photothermal fibers and fabrics, photothermal composite films, and photothermal shape memory materials.

[0014] The present invention has the following beneficial effects: (1) This invention addresses the inherent defects of single photothermal materials through the core-shell structure design of composite materials, achieving full-spectrum high-efficiency light absorption and photothermal conversion. Furthermore, surface modification with coupling agents enables the prepared photothermal particles to be uniformly dispersed in the polymer matrix, solving the problem of easy agglomeration and difficulty in uniform dispersion of micro- and nano-particles in the polymer matrix. It is also compatible with processing technologies such as fiber spinning and photothermal film preparation. Simultaneously, the core-shell photothermal particles can be applied to the fields of photothermal fibers, photothermal films, and photothermal shape memory materials to prepare photothermal conversion products with fast heating rates and large heating amplitudes, broadening the application range of high-efficiency photothermal conversion materials. It has strong versatility and broad industrialization prospects.

[0015] (2) This invention uses liquid metal as the core and titanium dioxide as the shell. The liquid metal absorbs visible and near-infrared light, while titanium dioxide absorbs ultraviolet light. The two wavelengths complement each other to achieve full-spectrum light absorption. The TiO2 shell not only serves as a dense protective layer to prevent the liquid metal from oxidizing and improve the cyclic photothermal stability, but also regulates the dielectric environment to optimize the LSPR wavelength matching biological window. Furthermore, it utilizes the Schottky barrier to promote the injection of hot electrons into TiO2, while holes remain in the TiO2 valence band, significantly reducing the energy loss of non-radiative recombination of charge carriers and further improving photothermal efficiency. The two-step process of air pre-calcination and high-temperature calcination in an inert atmosphere enables titanium dioxide to form a stable crystal form, while protecting the liquid metal from oxidation, maintaining the stability of the core-shell structure, preventing liquid metal leakage, and improving the durability of the material. Attached Figure Description

[0016] Figure 1 The image shows the photothermal fiber and fabric prepared in Example 4 of this invention. Figure 2 This is a photograph of the photothermal composite film prepared in Example 5 of the present invention. Figure 3 This is a physical image of the photothermal shape memory material prepared in Example 6 of the present invention, demonstrating shape memory recovery. Figure 4 The microstructure and composition analysis diagrams of the TiO2@LM core-shell photothermal material prepared in Example 1 of this invention are shown. Figure 5 The TiO2@LM core-shell photothermal material prepared in Example 1 of this invention and the ultraviolet-visible-near-infrared diffuse reflectance spectrum of TiO2 particles; Figure 6 Infrared thermal imaging images of the surface temperature evolution over time of TiO2@LM core-shell photothermal material, LM particles, TiO2, and LM+TiO2 simple blend particles prepared in Example 1 of the present invention under simulated sunlight. Figure 7 The graph shows the surface temperature evolution over time of the TiO2@LM core-shell photothermal material, LM particles, TiO2, and LM+TiO2 simple blend particles prepared in Example 1 of the present invention under simulated sunlight. Figure 8 The graphs show the surface temperature evolution over time and temperature rise of the TiO2@LM core-shell photothermal material prepared in Example 1 of this invention under different light irradiation powers. Figure 9 The graphs show the surface temperature evolution and temperature rise of the photothermal film prepared in Example 5 of this invention under different light irradiation powers over time. Figure 10 The graph shows the evolution of the surface temperature of the photothermal fabric prepared in Example 4 of this invention over time under simulated sunlight and natural sunlight. Detailed Implementation

[0017] The examples given below are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, conditions in the examples are performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0018] Example 1: A method for preparing a TiO2@LM core-shell photothermal material includes the following steps: (1) Preparation of liquid metal micro-nano particle dispersion: 400mg gallium indium alloy liquid metal was selected, 50mL of anhydrous ethanol was added, and ultrasonic dispersion was performed at 200W ultrasonic power for 4h to fully break the liquid metal into micro-nano particles and obtain a uniform and stable liquid metal micro-nano particle dispersion.

[0019] (2) Surface modification of liquid metal particles: 1 mL (per 50 mL dispersion) of ammonia water was added to the liquid metal micro-nano particle dispersion in step (1), and ultrasonically dispersed for 5 min; then 400 mg of hexadecylamine (per 50 mL dispersion) was added, and ultrasonically dispersed for 2 h. Through the surface modification effect of hexadecylamine, the surface hydrophilicity and hydrophobicity of liquid metal micro-nano particles were improved, and their interfacial bonding ability with inorganic titanium source was enhanced.

[0020] (3) In-situ coating of titanium dioxide shell: The modified dispersion was placed in an ice bath environment and the system temperature was controlled at 0℃. Under magnetic stirring at 700 rpm, isopropyl titanate was added slowly in a dropwise manner, with a dropwise amount of 500 μL (per 50 mL dispersion). After the dropwise addition was completed, the magnetic stirring was continued for 1 min to allow isopropyl titanate to hydrolyze and condense in situ on the surface of liquid metal micro-nano particles, forming a uniform titanium dioxide precursor shell. The obtained product was then centrifuged at 8000 rpm for 20 min, and the precipitate was collected. It was then washed three times by alternating ultrasonic centrifugation with deionized water and anhydrous ethanol to remove unreacted impurities and residual reagents. The washed product was placed in a -20℃ environment and frozen for 2 h. Then it was transferred to a vacuum freeze dryer and freeze-dried at -50℃ and a vacuum degree of 10 Pa for 24 h to obtain the core-shell precursor powder.

[0021] (4) Calcination and purification: The core-shell precursor powder was placed in a muffle furnace and heated to 450°C at a heating rate of 10°C / min under an air atmosphere, and held for 2 hours for pre-calcination. After the pre-calcined product was cooled, it was transferred to a tube furnace and heated to 700°C at a heating rate of 10°C / min under an argon atmosphere, and held for 1 hour for high-temperature calcination. After naturally cooling to room temperature, TiO2@LM core-shell photothermal micro-nanoparticles were obtained.

[0022] Example 2: A method for preparing a TiO2@LM core-shell photothermal material includes the following steps: (1) Preparation of liquid metal micro-nanoparticle dispersion: 400 mg of gallium indium tin liquid metal was selected and 50 mL of anhydrous ethanol was added. The mixture was ultrasonically dispersed for 3 h using 300 W ultrasonic power to fully break the liquid metal into micro-nanoparticles and obtain a uniform and stable liquid metal micro-nanoparticle dispersion.

[0023] (2) Surface modification of liquid metal particles: 1 mL (per 30 mL dispersion) of ammonia water was added to the liquid metal micro-nano particle dispersion in step (1), and ultrasonically dispersed for 5 min; then 200 mg of hexadecylamine (per 50 mL dispersion) was added, and ultrasonically dispersed for 2 h. Through the surface modification effect of hexadecylamine, the surface hydrophilicity and hydrophobicity of liquid metal micro-nano particles were improved, and their interfacial bonding ability with inorganic titanium source was enhanced.

[0024] (3) In-situ coating of titanium dioxide shell: The modified dispersion was placed in an ice bath environment and the system temperature was controlled at 5°C. Under magnetic stirring at 700 rpm, isopropyl titanate was added slowly in a dropwise manner, with a dropwise amount of 900 μL (per 50 mL dispersion). After the dropwise addition was completed, the magnetic stirring reaction was continued for 5 min, so that isopropyl titanate was hydrolyzed and condensed in-situ on the surface of liquid metal micro-nano particles to form a uniform titanium dioxide precursor shell.

[0025] (4) Calcination and purification: The product of step (3) was centrifuged at 8000 rpm for 20 min, and the precipitate was collected. It was washed three times by alternating ultrasonic centrifugation with deionized water and anhydrous ethanol to remove unreacted impurities and residual reagents. The washed product was placed in a -20℃ environment and frozen for 2 h. Then it was transferred to a vacuum freeze dryer and freeze-dried at -50℃ and a vacuum degree of 10 Pa for 24 h to obtain dried core-shell precursor powder. The precursor powder was placed in a muffle furnace and heated to 350℃ at a heating rate of 5℃ / min in an air atmosphere and held for 3 h for pre-calcination. After the pre-calcined product was cooled, it was transferred to a tube furnace and heated to 600℃ at a heating rate of 5℃ / min in an argon inert atmosphere and held for 2 h for high-temperature calcination. After naturally cooling to room temperature, TiO2@LM core-shell photothermal micro-nanoparticles were obtained.

[0026] Example 3: A method for preparing a TiO2@LM core-shell photothermal material includes the following steps: (1) Preparation of liquid metal micro-nanoparticle dispersion: 400 mg of gallium zinc alloy liquid metal was selected, 50 mL of anhydrous ethanol was added, and ultrasonic dispersion was performed at 400 W ultrasonic power for 5 h to fully break the liquid metal into micro-nanoparticles and obtain a uniform and stable liquid metal micro-nanoparticle dispersion.

[0027] (2) Surface modification of liquid metal particles: 1 mL (per 50 mL dispersion) of ammonia water was added to the liquid metal micro-nano particle dispersion in step (1), and ultrasonically dispersed for 5 min; then 600 mg of hexadecylamine (per 50 mL dispersion) was added, and ultrasonically dispersed for 2 h. Through the surface modification effect of hexadecylamine, the surface hydrophilicity and hydrophobicity of liquid metal micro-nano particles were improved, and their interfacial bonding ability with inorganic titanium source was enhanced.

[0028] (3) In-situ coating of titanium dioxide shell: The modified dispersion was placed in an ice bath environment and the system temperature was controlled at 3℃. Under magnetic stirring at 700 rpm, isopropyl titanate was added slowly in a dropwise manner, with a dropwise amount of 400 μL (per 50 mL dispersion). After the dropwise addition was completed, the magnetic stirring reaction was continued for 5 min, so that isopropyl titanate was hydrolyzed and condensed in-situ on the surface of liquid metal micro-nano particles to form a uniform titanium dioxide precursor shell.

[0029] (4) Calcination and purification: The product of step (3) was centrifuged at 8000 rpm for 20 min, and the precipitate was collected. It was washed three times by alternating ultrasonic centrifugation with deionized water and anhydrous ethanol to remove unreacted impurities and residual reagents. The washed product was placed in a -20℃ environment and frozen for 2 h. Then it was transferred to a vacuum freeze dryer and freeze-dried at -50℃ and a vacuum degree of 10 Pa for 24 h to obtain dried core-shell precursor powder. The precursor powder was placed in a muffle furnace and heated to 500℃ at a heating rate of 15℃ / min in an air atmosphere and held for 1 h for pre-calcination. After the pre-calcined product was cooled, it was transferred to a tube furnace and heated to 800℃ at a heating rate of 15℃ / min in an argon inert atmosphere and held for 0.5 h for high-temperature calcination. After naturally cooling to room temperature, TiO2@LM core-shell photothermal micro-nanoparticles were obtained.

[0030] Example 4: A method for preparing photothermal fibers and fabrics includes the following steps: (1) Prepare a 20% concentration polyurethane (TPU) solution, add TiO2@LM core-shell photothermal micro-nano particles prepared in Example 1 at a mass fraction of 10%, grind and mix evenly to obtain a spinning solution; (2) Photothermal fibers were prepared by wet spinning. The specific operation is as follows: at a flow rate of 0.2 mL / min, deionized water was used as the coagulation bath to prepare TiO2@LM / TPU fibers from the spinning solution in step (1). Then, the fibers were soaked and solidified for 24 h and dried at 80 °C for 15 min to obtain photothermal fibers. (3) The photothermal fibers from step (2) are woven into a plain weave fabric, such as... Figure 1 As shown in the test, the temperature rises by 75°C in 15 minutes under simulated sunlight, and by a maximum of 20°C under natural light.

[0031] Example 5: A method for preparing a photothermal composite film includes the following steps: (1) Prepare a 40% concentration TPU solution, add TiO2@LM core-shell photothermal micro-nano particles prepared in Example 1 at a mass fraction of 20%, grind and mix evenly to obtain TiO2@LM solution; (2) The photothermal composite film was prepared by spin coating. The specific operation is as follows: The TiO2@LM solution from step (1) was first rotated at 660 rpm for 6 seconds in a benchtop spin coater, and then rotated at 2700 rpm for 10 seconds. After drying, the photothermal composite film was obtained, as shown below. Figure 2 As shown.

[0032] Example 6: A method for preparing photothermal shape memory materials includes the following steps: The TiO2@LM core-shell photothermal particles prepared in Example 1 were blended with a citric acid-1,8-octanediol-caprolactone shape memory polymer matrix, wherein the mass fraction of the TiO2@LM core-shell photothermal particles was 15%. Photothermal shape memory materials were prepared by hot pressing. Under simulated sunlight irradiation, the photothermal conversion of the particles drove the material to rapidly achieve shape memory recovery, such as… Figure 3 As shown.

[0033] Experimental example: (1) Characterization of TiO2@LM core-shell photothermal material: The TiO2@LM core-shell photothermal material prepared in Example 1 was characterized using scanning electron microscopy. Figure 4 As shown in Figure a, the prepared TiO2@LM particles are nearly spherical with a relatively uniform particle size distribution, approximately 3 μm in diameter. The surface is rough and covered with a dense inorganic oxide layer. No obvious exposed liquid metal particles or free titanium dioxide particles were observed, indicating that the in-situ hydrolysis coating process can achieve uniform growth of titanium dioxide on the liquid metal surface. Further analysis using transmission electron microscopy revealed the fine internal structure of the particles. Figure 4 As shown in b, the particles exhibit a clear core-shell configuration, with a dark central region representing a high-electron-density liquid metal core and a uniformly thick light gray outer shell of titanium dioxide, approximately 0.5-1 μm thick. To clarify the spatial distribution characteristics of elements within the particles, surface scanning analysis was performed using a high-angle annular dark-field scanning transmission electron microscope combined with X-ray energy dispersive spectroscopy. Figure 4 As shown in c, the titanium element in the TiO2@LM particles is distributed on the outer periphery of the particles, corresponding to the titanium dioxide shell, directly proving the successful construction of the core-shell structure. High-resolution transmission electron microscopy image ( Figure 4In d), clear lattice fringes with a spacing of 0.35 nm can be observed. This characteristic spacing is in perfect agreement with the (101) crystal plane of anatase titanium dioxide, further confirming that anatase titanium dioxide has successfully formed a shell around liquid metal particles.

[0034] (2) Characterization of light absorption performance: diffuse reflectance absorption spectrum as shown in ( Figure 5 The results show that pure TiO2, limited by its intrinsic wide bandgap, exhibits strong absorption only in the ultraviolet region, reaching a peak absorbance of 1.18 at 320 nm. Absorbance rapidly decreases to below 0.2 in the visible and near-infrared regions above 400 nm. TiO2@LM core-shell particles, on the other hand, form a continuous and stable absorption plateau across the entire spectrum from 400 to 2500 nm, with absorbance maintained between 0.6 and 0.75.

[0035] (3) Characterization of photothermal conversion performance: The TiO2@LM core-shell photothermal material, LM particles, and TiO2 particles from Example 1 were irradiated for 10 min each using a xenon lamp simulating sunlight. Figure 6-7 It can be seen that the TiO2@LM particles in Example 1 rapidly heated to 51.7℃ within 1 minute and reached 65.6℃ within 10 minutes; the LM particles heated to 11.2℃ within 1 minute and reached 31.6℃ within 10 minutes; and the TiO2 particles heated to 4.4℃ within 1 minute and reached 6.5℃ within 10 minutes. A simple blend of LM particles and TiO2 particles heated to 35.3℃ within 1 minute and reached 44.2℃ within 10 minutes. These results indicate that the photothermal response rate and equilibrium heating amplitude of the TiO2@LM core-shell photothermal particles prepared in this invention are significantly superior to those of single LM particles, single TiO2 particles, and simple blends of the two.

[0036] The photothermal performance of the TiO2@LM core-shell photothermal material in Example 1 was tested at different power levels (350.0 W, 262.5 W, 175.0 W, and 87.5 W). Figure 8 It can be seen that the photothermal effect of TiO2@LM core-shell photothermal material increases in a positive gradient under different power illumination, indicating that its temperature change is greatly affected by external factors, making it a good photothermal conversion material.

[0037] Photothermal films with different TiO2@LM shell-core photothermal material contents from Example 5 were irradiated for 10 minutes using a xenon lamp simulating sunlight. Figure 9It can be seen that with the increase of TiO2@LM core-shell photothermal material content, the heating rate of the L photothermal film is faster and the temperature rise is greater. Under simulated sunlight (350W), the photothermal response of the 20% content photothermal film is the best: after 60 s of illumination, its surface temperature rises from 25.7℃ to 45.8℃, with a temperature rise of 20.1℃, which is significantly higher than other low content samples, indicating that the photothermal conversion efficiency exhibits a clear concentration dependence.

[0038] The photothermal properties of the plain weave fabric from Example 4 were tested under simulated sunlight conditions (xenon lamp and natural outdoor sunlight). Figure 10 It can be seen that under simulated sunlight conditions, the fabric surface temperature can rapidly rise from 26℃ to 101℃ and maintain a stable high temperature. After the sunlight stops, the temperature drops steadily, demonstrating rapid and well-controllable photothermal response. In natural sunlight environments, the fabric temperature changes synchronously with the daytime light intensity: at 9:00 AM, the fabric surface temperature is 28.7℃. As the sunshine duration increases, the temperature gradually rises, reaching a peak of approximately 48.8℃ at noon. Starting at 12:30 PM, the fabric temperature gradually decreases, reaching 30.6℃ by 6:00 PM.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a TiO2@LM core-shell photothermal material, characterized in that, Includes the following steps: (1) Preparation of liquid metal micro / nanoparticle dispersion: Liquid metal is added to anhydrous ethanol or acetone and ultrasonically dispersed to obtain liquid metal micro / nanoparticle dispersion; (2) Surface modification of liquid metal particles: Ammonia water was added to the liquid metal micro-nano particle dispersion in step (1) and ultrasonic dispersion was performed for the first time. Then hexadecylamine was added and ultrasonic dispersion was performed for the second time to obtain the modified dispersion. (3) In-situ coating of titanium dioxide shell: Cool the dispersion modified in step (2) to 0~5℃, add isopropyl titanate dropwise under stirring to react, then collect the precipitate by centrifugation, wash the precipitate with deionized water and anhydrous ethanol, and freeze-dry to obtain core-shell precursor powder. (4) Calcination purification: The core-shell precursor powder from step (3) is calcined in air at 350-500°C for 1-3 hours. The resulting product is then cooled to room temperature and calcined in an inert atmosphere at 600-800°C for 0.5-2 hours. The resulting product is then cooled to room temperature to obtain the product.

2. The preparation method according to claim 1, characterized in that, The liquid metal mentioned in step (1) is a gallium-based liquid metal.

3. The preparation method according to claim 2, characterized in that, The gallium-based liquid metal includes at least one of gallium indium tin alloy, gallium indium alloy, gallium tin alloy, and gallium zinc alloy.

4. The preparation method according to claim 1, characterized in that, The volume ratio of the liquid metal micro / nanoparticle dispersion to ammonia in step (2) is 30-70:1; the ratio of the amount of hexadecylamine to the liquid metal micro / nanoparticle dispersion is 4-12:1 (w / v).

5. The preparation method according to claim 1, characterized in that, The volume ratio of the dispersion to the isopropyl titanate in step (3) is 60~140:

1.

6. The preparation method according to claim 1, characterized in that, The heating rate of the heat preservation calcination in step (4) is 5~15℃ / min.

7. TiO2@LM core-shell photothermal material prepared by the preparation method according to any one of claims 1-6.

8. The application of the TiO2@LM core-shell photothermal material according to claim 7 in the preparation of photothermal conversion materials.

9. A photothermal conversion material, characterized in that, This includes the TiO2@LM core-shell photothermal material as described in claim 7.

10. The photothermal conversion material according to claim 9, characterized in that, The photothermal conversion material is one of the following: photothermal fiber and fabric, photothermal composite film, and photothermal shape memory material.

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