Photothermal composite material, photothermal material composite film and preparation method

Abstract

The present invention discloses a photothermal composite material, a photothermal material composite film and a preparation method. The photothermal composite material is composed of a WS2 particle core, which is wrapped with polydopamine. After calcination, a carbon-wrapped WS2 particle core structure is formed. An irregular metallic Bi element is generated on the surface of the carbon-wrapped WS2 particles by a reduction method. The photothermal material composite film uses WS2@C-PDA / Bi material as an active layer and a porous polyvinylidene fluoride (PVDF) membrane as a substrate. The WS2@C-PDA / Bi material layer is combined with the PVDF membrane. The membrane is prepared by vacuum filtration and depositing the WS2@C-PDA / Bi material on the PVDF membrane. The present invention realizes the efficient coupling of solar-driven freshwater collection and carbon dioxide reduction, which not only has significant economic and environmental benefits, but also provides a new solution to the problems of freshwater shortage and excessive carbon dioxide emissions.

Description

Technical Field

[0001] The present invention belongs to the technical field of photothermal materials, and specifically relates to a photothermal composite material, a photothermal material composite film and a preparation method. Background Art

[0002] With the rapid development of human society, the demand for energy and freshwater resources has increased dramatically, leading to an increasing scarcity of freshwater resources. Furthermore, human activities not only consume energy and freshwater resources but also emit large amounts of CO2 into the atmosphere, triggering a greenhouse effect that continues to damage the Earth's environment. To address this challenge, extensive research has been conducted on photothermal coupled catalytic systems, aiming to efficiently utilize solar energy and achieve synergistic and efficient desalination and green energy conversion.

[0003] Photothermal nanomaterials hold great promise for applications in solar desalination, carbon dioxide reduction, and hydrogen production. These light-absorbing materials efficiently absorb light energy and convert it into heat, significantly improving evaporation performance. Furthermore, the electron-hole pairs generated by these materials under illumination can effectively enhance the activity of photocatalysts, promoting the conversion of solar energy into chemical energy.

[0004] In order to effectively utilize photothermal materials, the current strategy is mainly to directly confine the heat energy converted from solar energy between interfaces. A common method is to float photothermal materials on the surface of the water body. After converting solar energy into heat energy, the photothermal materials are confined to the surface water layer instead of heating the entire water body. This allows the heat energy to be directly and effectively absorbed and utilized by the surface water layer, thereby improving the overall photothermal conversion efficiency.

[0005] Through further research, the present invention aims to provide a photothermal material that can simultaneously take into account photothermal conversion and carbon dioxide reduction.

[0006] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to provide a photothermal composite material, a photothermal material composite film and a preparation method, which realizes efficient seawater evaporation and CO2 reduction driven by solar energy through photothermal coupling technology.

[0008] In order to achieve the above object, a specific embodiment of the present invention provides the following technical solutions:

[0009] A photothermal composite material, comprising tungsten disulfide as a core, a carbon layer covering the core surface, and bismuth element loaded on the carbon layer surface.

[0010] In one or more embodiments of the present invention, the carbon layer has a thickness of 16 to 150 nm.

[0011] In one or more embodiments of the present invention, tungsten disulfide coated with a carbon layer is used as a carrier, and the loading amount of the bismuth element is ≤100%.

[0012] In one or more embodiments of the present invention, the particle size of the tungsten disulfide is 1-5 μm.

[0013] Another specific embodiment of the present invention provides a technical solution as follows:

[0014] A method for preparing a photothermal composite material comprises the following steps:

[0015] Coating a carbon layer on the surface of tungsten disulfide to obtain a carbon-coated tungsten disulfide material;

[0016] The carbon-coated tungsten disulfide material is dispersed in a bismuth source solution, a reducing agent is added for reduction, and then centrifuged, and the precipitate is collected and dried to obtain a photothermal composite material.

[0017] In one or more embodiments of the present invention, the mass ratio of the carbon-coated tungsten disulfide material to the bismuth source, calculated as bismuth element, is 100:(1-100).

[0018] In one or more embodiments of the present invention, the carbon-coated tungsten disulfide material is prepared as follows:

[0019] Tungsten disulfide is dispersed in a solvent, and dopamine hydrochloride solution is added according to the mass ratio of tungsten disulfide to dopamine hydrochloride of 1: (0.5-2). After the reaction, centrifugation is performed, and the precipitate is collected and freeze-dried to obtain a polydopamine-coated tungsten disulfide material.

[0020] The polydopamine-coated tungsten disulfide material is calcined at 600-800° C. for 0.5-3 hours to obtain a carbon-coated tungsten disulfide material.

[0021] Another specific embodiment of the present invention provides a technical solution as follows:

[0022] A photothermal material composite film comprises a base layer and an active layer arranged on the base layer, wherein the active layer is formed by the above-mentioned photothermal composite material or the photothermal composite material prepared by the above-mentioned method for preparing the photothermal composite material.

[0023] In one or more embodiments of the present invention, the base layer is a polyvinylidene fluoride film, a mixed cellulose ester film or a polypropylene film.

[0024] Another specific embodiment of the present invention provides a technical solution as follows:

[0025] A method for preparing a photothermal material composite film comprises the following steps:

[0026] dispersing the photothermal composite material in deionized water to obtain a dispersion;

[0027] The dispersion is poured into a suction filtration device equipped with a base layer, and then filtered, and then dried to obtain a photothermal material composite membrane.

[0028] Compared with the existing technology, the present invention innovatively designs the WS2@C-PDA / Bi material, which has a core-shell structure with a tungsten disulfide (WS2) core, an external carbon layer, and metallic bismuth loaded on the carbon layer. The WS2 core provides excellent photothermal conversion performance, and the external carbon layer increases the light absorption area and photothermal conversion efficiency while maintaining the generated heat and reducing radiation loss. The loading of metallic bismuth further enhances the photocatalytic performance and significantly promotes the carbon dioxide reduction reaction.

[0029] In addition, the present invention designs a photothermal material composite membrane, the active layer of which is composed of the prepared WS2@C-PDA / Bi material, and the lower part is a polyvinylidene fluoride (PVDF) membrane. The photothermal material composite membrane is assembled into an interface system, which can not only effectively convert light energy into heat energy, thereby realizing seawater evaporation and desalination, but also use photocatalysis to reduce carbon dioxide to carbon monoxide and methane.

[0030] The multifunctional membrane structure of the photothermal composite membrane combines both photothermal and photocatalytic functions. The PVDF membrane provides excellent mechanical strength and chemical stability, ensuring the long-term stable operation of the system. This membrane demonstrates significant advantages in solar-driven freshwater collection and carbon dioxide reduction processes, not only improving the overall efficiency of the system but also providing important insights for future energy capture and resource utilization technologies. This innovation not only has significant economic and environmental benefits but also offers a new solution to addressing freshwater shortages and excessive carbon dioxide emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic structural diagram of a photothermal material composite film according to an embodiment of the present invention;

[0033] Figure 2 : This is a projection electron microscope image of WS2@C-PDA particles in Example 1 of the present invention;

[0034] Figure 3 The original WS2 material, the material after calcination with PDA loading, and the material after Bi loading in Example 1 of the present invention;

[0035] Figure 4 Schematic diagram of the 3D structure of WS2@C-PDA / Bi material in Example 1 of the present invention;

[0036] Figure 5 Element distribution diagram of WS2@C-PDA / Bi material in Example 1 of the present invention;

[0037] Figure 6 This is an SEM image of the raw material WS2 in Example 1 of the present invention;

[0038] Figure 7 This is the SEM image of the WS2@C-PDA material in Example 1 of the present invention;

[0039] Figure 8 This is the SEM image of the WS2@C-PDA / Bi material in Example 1 of the present invention;

[0040] Figure 9 XRD images of the raw material WS2, WS2@C-PDA material, and WS2@C-PDA / Bi material in Example 1 of the present invention;

[0041] Figure 10 This is a schematic diagram of the structure of the interface floating system in the evaporation test;

[0042] Figure 11 (a) is a comparison chart of the evaporation rates in Examples 1-7 and Comparative Example 1;

[0043] Figure 11 (b) is the evaporation rate of WS2@C-PDA / Bi@PVDF membrane in Example 5;

[0044] Figure 12 A comparison chart of carbon dioxide reduction in Examples 1-7 and Comparative Example 1;

[0045] Figure 13 This is the absorbance graph of the raw material WS2 and WS2@C-PDA / Bi material in Example 5 of the present invention;

[0046] Figure 14 PC response diagram of WS2@C-PDA / Bi materials in Examples 1-7 of the present invention and Comparative Example 1;

[0047] Figure 15 Schematic diagram of seawater evaporation and CO2 reduction using the WS2@C-PDA / Bi material of the present invention. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0049] A specific embodiment of the present invention provides a photothermal composite material, which uses tungsten disulfide as a core, the surface of the core is coated with a carbon layer, and the surface of the carbon layer is loaded with bismuth elements.

[0050] Furthermore, the bismuth element is selected from metallic bismuth. Preferably, the bismuth element is nano-metal bismuth particles, and the particle size of the nano-metal bismuth particles is 20 to 60 nm.

[0051] Specifically, tungsten disulfide (WS2) has excellent photothermal properties and can absorb light energy and convert it into heat energy. Metallic bismuth has high catalytic activity and can effectively promote the reaction of carbon dioxide. The material prepared by compounding tungsten disulfide and bismuth has good chemical and thermal stability and can maintain stable operation for a long time at high temperature. In addition, the use of a carbon layer to isolate the internal tungsten disulfide particles from the metallic bismuth can effectively promote the separation of photogenerated carriers and further enhance the catalytic activity and photothermal effect of the photothermal composite material. Moreover, wrapping a carbon layer on the surface of tungsten disulfide can improve the photothermal conversion efficiency of tungsten disulfide because the carbon layer provides a larger light absorption area and better thermal conductivity. In addition, the presence of the carbon layer can effectively maintain the heat generated by the internal tungsten disulfide particles, reduce heat radiation loss, increase the surface area of ​​the photothermal composite material, expand the contact with the catalyzed substance, and improve the catalytic efficiency.

[0052] Furthermore, the particle size of tungsten disulfide is 1-5 μm, the thickness of the carbon layer is 16-150 nm, and the tungsten disulfide coated with the carbon layer is used as a carrier, and the loading amount of the bismuth element is ≤100%.

[0053] Specifically, controlling the thickness of the carbon layer helps improve the photothermal conversion efficiency of the photothermal composite material, thereby increasing the evaporation of seawater. Simultaneously, controlling the tungsten disulfide particle size and bismuth loading further ensures the photothermal composite material has excellent photothermal conversion performance.

[0054] Another specific embodiment of the present invention provides a method for preparing a photothermal composite material, comprising steps 1-2.

[0055] Step 1: coating a carbon layer on the surface of tungsten disulfide to obtain a carbon-coated tungsten disulfide material.

[0056] Specifically, tungsten disulfide powder is added to a sodium bicarbonate solution and stirred at 400-1000 rpm for 30-60 minutes using magnetic stirring to achieve uniform dispersion. Dopamine hydrochloride is also prepared, with a mass ratio of tungsten disulfide powder to dopamine hydrochloride of 1:(0.5-2), preferably 1:1. The dopamine hydrochloride is ultrasonically dissolved in the sodium bicarbonate solution. The resulting dopamine hydrochloride solution is then added to the tungsten disulfide dispersion and stirred at 4000-10000 rpm for 6-24 hours. The mixture is then centrifuged at 4000-10000 rpm for 3-5 minutes. The resulting precipitate is washed once with deionized water and once with anhydrous ethanol, then freeze-dried overnight in a freeze dryer. A fully dried powder sample is collected to obtain a polydopamine-coated tungsten disulfide material. The sodium bicarbonate solution provides an alkaline environment, allowing the dopamine hydrochloride to polymerize to form polydopamine. In addition to sodium bicarbonate, other substances that can provide an alkaline environment can also be used.

[0057] Then the polydopamine-coated tungsten disulfide material is placed in a tube furnace, the temperature is raised to 600-800° C. at a heating rate of 2-5° C. / min, and calcined for 0.5-3 h to obtain a carbon-coated tungsten disulfide material.

[0058] Furthermore, polydopamine (PDA) has excellent coating ability when used as a coating material. PDA can form a uniform coating on the surface of tungsten disulfide, and the polyphenol groups in its molecules can be tightly bound to tungsten disulfide through covalent and non-covalent bonds, ensuring the uniformity and integrity of the coating process. In addition, PDA has good biocompatibility and is very suitable for use in biomedical and environmental applications without causing adverse reactions or pollution. The functional groups on the surface of PDA (such as amino and hydroxyl groups) are easy to further modify and functionalize, thereby giving the material more functional properties. During the calcination process, PDA can be converted into a carbon layer to form a stable carbon coating structure. This carbon layer not only enhances the photothermal performance, but also provides more active sites and improves the catalytic efficiency.

[0059] Step 2: dispersing the carbon-coated tungsten disulfide material in a bismuth source solution, adding a reducing agent for reduction, and then centrifuging to collect and dry the precipitate to obtain a photothermal composite material.

[0060] Furthermore, the bismuth source is a water-soluble bismuth salt, preferably, the bismuth source is bismuth nitrate hydrate, and more preferably, the bismuth source is bismuth nitrate pentahydrate.

[0061] Specifically, the mass ratio of the carbon-coated tungsten disulfide material to the bismuth source, calculated as bismuth element, is 100:(1-100). Taking bismuth nitrate pentahydrate as an example, the bismuth nitrate pentahydrate is dissolved in water at a mass ratio of 100:(2.32-232). The carbon-coated tungsten disulfide material is then dispersed in the bismuth nitrate pentahydrate aqueous solution. A 0.4M sodium borohydride aqueous solution is then slowly added dropwise under stirring. The amount of sodium borohydride aqueous solution can be adjusted according to the mass of the bismuth nitrate pentahydrate, with a maximum amount of 62.5 ml. After the addition is complete, stirring is continued at 400-1000 rpm for 30-60 minutes, followed by centrifugation at 4000-10000 rpm. The precipitate is collected and dried to obtain the photothermal composite material. Sodium borohydride acts as a reducing agent to react with bismuth nitrate pentahydrate to produce elemental bismuth. In addition to sodium borohydride, other available reducing agents can also be used.

[0062] Another specific embodiment of the present invention provides a photothermal material composite film, such as Figure 1 As shown, it includes a base layer and an active layer arranged on the base layer, and the active layer is formed by the above-mentioned photothermal composite material or the photothermal composite material prepared by the above-mentioned preparation method of the photothermal composite material.

[0063] Specifically, the base layer can be a polyvinylidene fluoride membrane (PVDF membrane), a mixed cellulose ester membrane, or a polypropylene membrane, preferably a polyvinylidene fluoride membrane. PVDF membranes have excellent mechanical strength and durability, can maintain integrity and stability under various harsh conditions, and provide reliable structural support; PVDF membranes have good tolerance to many chemicals and can resist corrosion by acids, alkalis, and organic solvents, ensuring long-term use in complex chemical environments; PVDF membranes have high thermal stability and can be used in high-temperature environments without degradation, making them suitable for applications requiring high-temperature operation; PVDF membranes can also maintain their performance in aqueous environments, making them particularly suitable for water treatment applications such as desalination.

[0064] Another specific embodiment of the present invention provides a method for preparing a photothermal material composite film, comprising the following steps:

[0065] dispersing the photothermal composite material in deionized water to obtain a dispersion;

[0066] The dispersion is poured into a suction filtration device equipped with a base layer, and then filtered, and then dried to obtain a photothermal material composite membrane.

[0067] The present invention is further described in detail below with reference to specific embodiments.

[0068] Example 1

[0069] 1g of 2μm WS2 was added to 80ml of 0.1M NaHCO3 solution and magnetically stirred at 400rpm for 30min to achieve uniform dispersion, yielding Solution A. 1g of dopamine hydrochloride was weighed and dissolved in 20ml of 0.1M NaHCO3 solution, followed by sonication for 30min to yield Solution B. Solution B was slowly added to Solution A to yield Solution C, which was stirred at 400rpm for 24h. The mixture was then centrifuged at 8000rpm for 5min, and the precipitate was collected. The precipitate was washed with deionized water and then anhydrous ethanol, followed by freeze-drying overnight in a vacuum dryer. A fully dried powder sample was collected to yield WS2@PDA powder.

[0070] The WS2@PDA powder was placed in a tube furnace, heated to 700°C at a heating rate of 3°C / min, and calcined for 3 h to obtain the WS2@C-PDA material. Figure 2 It can be seen that there is a carbon layer on the surface of WS2 located in the core.

[0071] Take 0.012g of bismuth nitrate pentahydrate and dissolve it in 100ml of deionized water. Take another 100mg of WS2@C-PDA material and add it to the bismuth nitrate pentahydrate solution. Then, under stirring, slowly add 3.125ml of 0.4M sodium borohydride aqueous solution. After the addition is complete, continue stirring for 30 minutes. The solution is then centrifuged at 8000rpm, the precipitate is collected and dried at 60°C to obtain WS2@C-PDA / Bi material, that is, a photothermal composite material. The loading amount of bismuth element on WS2@C-PDA material is 5%, and the loading amount is calculated as (bismuth element mass / WS2@C-PDA material mass)*100%.

[0072] The 3D structure diagram of WS2@C-PDA / Bi material is shown in Figure 4 As shown, the photothermal reaction core is WS2, its surface is covered with a carbon layer, and the surface of the carbon layer is loaded with nano-metal particles, namely metal bismuth. Figure 5 From the element distribution diagram, it can be found that there are carbon and bismuth elements on the surface of WS2; Figure 6-8 From the morphology diagram, we can see that after carbon coating, the surface morphology of the original WS2 changes from irregular to relatively rounded, and irregular sticks appear on the surface of WS2@C-PDA / Bi nanoparticles, confirming the loading of metal Bi. Figure 9 In the XRD pattern, obvious characteristic peaks of Bi element appeared at 22.5°, 27.5° and 38° (PDF 00-005-0519), which also confirmed that Bi element was successfully loaded.

[0073] 10 mg of WS2@C-PDA / Bi material was placed in a 200 ml beaker, and 150 ml of deionized water was added. The solution was magnetically stirred for 1 hour and ultrasonicated for 20 minutes, repeated three times to form a homogeneous solution. The solution was then vacuum filtered through a filtration apparatus containing a 50 mm diameter, 0.45 μm pore size PVDF membrane. After filtration, the membrane was removed and allowed to air dry at room temperature to obtain the WS2@C-PDA / Bi@PVDF membrane, a photothermal composite membrane designated WCB-5.

[0074] Examples 2-7

[0075] The operation of Examples 2-7 is the same as that of Example 1, except that the amounts of bismuth nitrate pentahydrate and sodium borohydride aqueous solution are different, as shown in Table 1.

[0076] Table 1 Amount of raw materials in Examples 1-7

[0077]

[0078] Comparative Example 1

[0079] 1g of 2μm WS2 was added to 80ml of 0.1M NaHCO3 solution and magnetically stirred at 400rpm for 30min to achieve uniform dispersion, yielding Solution A. 1g of dopamine hydrochloride was weighed and dissolved in 20ml of 0.1M NaHCO3 solution, followed by sonication for 30min to yield Solution B. Solution B was slowly added to Solution A to yield Solution C, which was stirred at 400rpm for 24h. The mixture was then centrifuged at 8000rpm for 5min, and the precipitate was collected. The precipitate was washed with deionized water and then anhydrous ethanol, followed by freeze-drying overnight in a vacuum dryer. A fully dried powder sample was collected to yield WS2@PDA powder.

[0080] The WS2@PDA powder was placed in a tube furnace, heated to 700°C at a heating rate of 3°C / min, and calcined for 3 h to obtain the WS2@C-PDA material.

[0081] 10 mg of WS2@C-PDA was placed in a 200 ml beaker, followed by 150 ml of deionized water. The solution was stirred magnetically for 1 hour and then sonicated for 20 minutes, repeated three times to create a homogeneous solution. The solution was then vacuum filtered through a filtration apparatus containing a 50 mm diameter, 0.45 μm pore size PVDF membrane. After filtration, the membrane was removed and allowed to air dry at room temperature. This photothermal composite membrane, designated WCB-0, was obtained.

[0082] The following tests were performed on the photothermal material composite films in each embodiment and comparative example:

[0083] (1) Evaporation test: Figure 10 As shown, the photothermal material composite film is placed on absorbent cotton, which is bonded to polyethylene foam to form an interface floating system. The absorbent cotton wraps the upper part of the foam, and the foam provides buoyancy. The absorbent cotton absorbs water to the bottom of the photothermal material composite film for evaporation. The system is placed in a container filled with seawater, and the container is placed on a balance. The balance is connected to a computer and records the change in weight after evaporation of water through the computer. The balance is placed under a solar simulator, and the solar simulator simulates sunlight irradiating the photothermal material composite film. The irradiation intensity is set to 1000w / m 2 .

[0084] (2) Carbon dioxide reduction test: 50 mg of WS2@C-PDA / Bi material was dispersed in 100 mL of distilled water without any sacrificial agent. The reaction solution was kept at 5 °C by a circulating cooling water system, and then evacuated several times to completely remove the air. A 300 W Xe lamp was used as the light source. The generated gas was detected by a TCD equipped with a The molecular sieve column is measured by gas chromatography (using argon as the carrier gas). In addition, the gas chromatograph is used to detect the peak signals of CH4, CO, etc., and then the rate of CO2 reduction to CH4 and CO is calculated as follows:

[0085]

[0086] Figure 11 In the figure, the Bi concentration (%) on the horizontal axis refers to the loading amount of bismuth on the WS2@C-PDA material. Figure 11 It can be seen that in the evaporation test, the seawater evaporation efficiency of the photothermal material composite film in Comparative Example 1 is the lowest. The photothermal material composite films loaded with bismuth in the embodiments of the present invention can effectively convert light energy into heat to achieve photothermal seawater evaporation. Among them, the evaporation rate of the WCB-40 film is the highest. At 30 minutes, the seawater evaporation rate of the WCB-40 film reaches a stable level, and the average evaporation rate after 30 minutes can reach about 1.12 kg / m 2 / h.

[0087] Figure 12 In the figure, the Bi concentration (%) on the horizontal axis refers to the loading amount of bismuth on the WS2@C-PDA material. Figure 12 It can be seen that in the carbon dioxide reduction test, compared with comparative example 1, the photothermal composite material loaded with metal bismuth element in the present invention can effectively reduce carbon dioxide. When the loading amount of metal bismuth element is 40%, the CO yield of WS2@C-PDA / Bi@PVDF membrane reaches 9.18mmol / g, which is the best performance. Figure 13 It can be seen that in the sunlight band of 200 to 2500 nm, the absorbance of the WCB-40 sample is as high as 91%. Figure 14 In the table, 0 represents WCB-0, 10 represents WCB-10, 40 represents WCB-40, 50 represents WCB-50, and 100 represents WCB-100. Figure 14 It can be seen that in the photoelectrochemical response results, the light response intensity of the WCB-40 sample is the strongest, indicating that the WCB-40 sample has a higher rapid transfer and separation of light-induced charges, which is more conducive to CO2 reduction.

[0088] In summary, if Figure 15 As shown in the figure, the present invention realizes solar-driven seawater evaporation and CO2 reduction through photothermal coupling technology, providing a new solution to alleviate freshwater shortage and environmental problems. The photothermal material composite film in the present invention is used as the photothermal layer, foam is used as the thermal insulation layer, and absorbent cotton is used as the water transport layer to form an interface photothermal seawater evaporation structure. In specific applications, photothermal seawater evaporation and desalination can be achieved, and its evaporation and desalination efficiency reaches 1.12kg / m 2 While generating photothermal energy, the photothermal layer is also stimulated by light and photocatalyzed to reduce CO2 to CO at a maximum yield of 9.18 mmol / g.

[0089] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0090] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A photothermal composite material, characterized in that: The photothermal composite material uses tungsten disulfide as a core, the surface of the core is coated with a carbon layer, and the surface of the carbon layer is loaded with bismuth elements.

2. The photothermal composite material according to claim 1, characterized in that: The carbon layer has a thickness of 16 to 150 nm.

3. The photothermal composite material according to claim 1, characterized in that: Tungsten disulfide coated with a carbon layer is used as a carrier, and the loading amount of the bismuth element is ≤100%.

4. The photothermal composite material according to claim 1, characterized in that: The particle size of the tungsten disulfide is 1 to 5 μm.

5. A method for preparing a photothermal composite material, characterized in that: The following steps are involved: Coating a carbon layer on the surface of tungsten disulfide to obtain a carbon-coated tungsten disulfide material; The carbon-coated tungsten disulfide material is dispersed in a bismuth source solution, a reducing agent is added for reduction, and then centrifuged, and the precipitate is collected and dried to obtain a photothermal composite material.

6. The method for preparing the photothermal composite material according to claim 5, characterized in that: The mass ratio of the carbon-coated tungsten disulfide material to the bismuth source, calculated as bismuth element, is 100:(1-100).

7. The method for preparing the photothermal composite material according to claim 5, characterized in that: The preparation of carbon-coated tungsten disulfide material is as follows: Tungsten disulfide is dispersed in a solvent, and dopamine hydrochloride solution is added according to the mass ratio of tungsten disulfide to dopamine hydrochloride of 1: (0.5-2). After the reaction, centrifugation is performed, and the precipitate is collected and freeze-dried to obtain a polydopamine-coated tungsten disulfide material. The polydopamine-coated tungsten disulfide material is calcined at 600-800° C. for 0.5-3 hours to obtain a carbon-coated tungsten disulfide material.

8. A photothermal material composite film, characterized in that: The invention comprises a base layer and an active layer arranged on the base layer, wherein the active layer is formed by the photothermal composite material according to any one of claims 1 to 4 or the photothermal composite material prepared by the preparation method of the photothermal composite material according to any one of claims 5 to 7.

9. The photothermal material composite film according to claim 8, characterized in that: The base layer is a polyvinylidene fluoride film, a mixed cellulose ester film or a polypropylene film.

10. A method for preparing a photothermal material composite film, characterized in that: The steps include: Dispersing the photothermal composite material in deionized water to obtain a dispersion; the photothermal composite material is the photothermal composite material according to any one of claims 1 to 4 or the photothermal composite material prepared by the method for preparing the photothermal composite material according to any one of claims 5 to 7; The dispersion is poured into a suction filtration device equipped with a base layer, and then filtered, and then dried to obtain a photothermal material composite membrane.

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