A Janus structure photothermal fabric with adjustable wettability and its preparation method and application

Abstract

The present invention discloses a Janus structure photothermal fabric with adjustable wettability, a preparation method and an application thereof, and belongs to the technical field of solar interfacial water evaporation. The Janus structure photothermal fabric with adjustable wettability is based on a hydrophobic carbon fiber fabric, one side of the hydrophobic carbon fiber fabric is a hydrophilic layer, and the other side is a hydrophobic layer, the hydrophilic layer is a deposited CuS layer, and the hydrophobic layer is an undeposited CuS layer. The hydrophilic layer is a hydrophilic layer with radial pores formed by the CuS nanosheets grown on the surface of the hydrophobic carbon fiber fabric, which are intertwined and connected with each other. It can solve the problems of heat loss caused by water energy imbalance in the evaporation process of the existing two-dimensional evaporator, salt deposition on the evaporator surface, and eliminate the inevitable mutual influence caused by the coexistence of light absorption and water transmission in the same space of the evaporator, thereby improving the high efficiency and long-term stability of the evaporator.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar interface water evaporation, and in particular relates to a Janus structure photothermal fabric with adjustable wettability, a preparation method and an application thereof. Background Art

[0002] Producing freshwater from non-drinking sources such as seawater or sewage is an effective way to alleviate freshwater shortages. To this end, many researchers have explored various approaches, including reverse osmosis, electroosmosis, and thermal distillation. However, these technologies consume large amounts of fossil fuels, inevitably impacting the environment and incurring significant economic costs, hindering sustainable development. Inspired by natural evaporation, solar-driven evaporation, which utilizes renewable solar energy as the sole energy input, has been recognized as a promising and sustainable solution. In particular, solar-driven interfacial evaporation (SDIE) has emerged as a cost-effective freshwater production technology. This technology captures incident sunlight through a solar absorber and converts it into localized thermal energy, which is confined to the water / air interface, where water evaporates. This technology requires the coordinated operation of a solar absorber, heat localization, and water supply components.

[0003] Carbon fiber fabric, a type of carbon-based material, is considered an ideal photothermal material due to its inherent broadband absorption properties, low cost, easy structural control, and minimal environmental impact. When used as a photothermal evaporator, superhydrophilic carbon fiber fabric can simultaneously achieve high light absorption and rapid water transport. However, because solar light absorption, water transport, and vapor escape coexist on the same surface, they inevitably interact, resulting in impaired performance. Current SDIE systems also fail to fully consider the supply and demand relationship of the evaporation process. This results in excessive water supply causing significant heat loss, while insufficient water supply leads to salt deposition on the evaporation surface, clogging the evaporator and compromising light absorption performance, continuous water supply, and the long-term stability of the evaporator.

[0004] Therefore, it is particularly important to separate light absorption and water evaporation by preparing a wettable surface and to regulate the water content of the hydrophilic layer to establish a long-term stable water-energy balance during the evaporation process. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a Janus structure photothermal fabric with controllable wettability, as well as its preparation method and application, to solve the problems of heat loss caused by water energy imbalance during the evaporation process of the existing two-dimensional evaporator, salt deposition on the evaporator surface, and eliminate the inevitable mutual influence caused by the coexistence of light absorption and water transmission in the same space of the evaporator, thereby improving the high efficiency and long-term stability of the evaporator.

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

[0007] The present invention provides a Janus structure photothermal fabric with adjustable wettability. The Janus structure photothermal fabric with adjustable wettability uses a hydrophobic carbon fiber fabric as a substrate, one side of the hydrophobic carbon fiber fabric is a hydrophilic layer, and the other side is a hydrophobic layer, the hydrophilic layer is a deposited CuS layer, and the hydrophobic layer is an undeposited CuS layer.

[0008] In one embodiment, the hydrophilic layer is a hydrophilic layer having radial pores formed by interlacing and connecting CuS nanosheets grown on the surface of the hydrophobic carbon fiber fabric.

[0009] The present invention also provides a method for preparing a Janus structured photothermal fabric with controllable wettability, comprising the following steps:

[0010] After cleaning, the hydrophobic carbon fiber fabric is placed in a magnetron sputtering system. Argon is used as the sputtering gas to remove impurities on the surface of the hydrophobic carbon fiber fabric to obtain a clean hydrophobic carbon fiber fabric. For the Cu target, a pre-sputtering treatment is performed to remove the oxide layer on the copper surface to obtain a Cu target without a surface oxide layer.

[0011] A Cu target is sputtered on the surface of a clean hydrophobic carbon fiber fabric using a DC power supply to obtain a hydrophobic carbon fiber fabric with a Cu layer deposited on one side; sodium hydroxide and sulfur powder are dissolved in polyethylene glycol and deionized water as solvents to obtain a yellow mixed solution;

[0012] The hydrophobic carbon fiber fabric with a Cu layer deposited on one side was immersed in a yellow mixed solution, and the copper sulfide layer was grown by reaction, then rinsed and dried to obtain a Janus structure photothermal fabric with controllable wettability.

[0013] In one embodiment, the process of using argon as a sputtering gas to remove impurities on the surface of the hydrophobic carbon fiber fabric is as follows:

[0014] The high vacuum state in the chamber is 1.8×10 -3 Pa, 50 sccm of argon was introduced, the pressure was increased to 6 Pa, a bias of 400 V was applied, and the bombardment was carried out for 5-10 min.

[0015] In one embodiment, the pre-sputtering treatment is performed under a vacuum degree of 0.6 Pa, the pre-sputtering power is 80-100 W, and the pre-sputtering time is 5-10 min.

[0016] In one embodiment, the current when sputtering the Cu target by a DC power supply is 0.3 A, the sputtering power is 80-100 W, the rotation speed of the clean hydrophobic carbon fiber fabric is 8-13 r / min, and after starting the power supply, the Cu target surface is glowed and discharged, and the sputtering time is 30-80 min.

[0017] In one embodiment, the mass ratio of the sodium hydroxide to the sulfur powder is 2-3:1; and the volume ratio of the polyethylene glycol to the deionized water is 1-2:15.

[0018] In one embodiment, the dissolving is carried out by stirring and dissolving at a temperature of 60-70° C., and the stirring and dissolving time is 15-20 minutes;

[0019] During the immersion, the temperature of the yellow mixed solution is 20-25° C., and the reaction time is 2-3 minutes; the rinsing is performed using propanol and deionized water, and the number of rinsing times is 3-5 times; the drying temperature is 60-65° C., and the drying time is 3-3.5 hours.

[0020] In one embodiment, during the reaction growth of the copper sulfide layer, the color of the surface of the hydrophobic carbon fiber fabric with the Cu layer deposited on one side changes from copper color to black to generate a CuS layer to form a hydrophobic carbon fiber fabric with the CuS layer deposited on one side, and the surface wettability of the hydrophobic carbon fiber fabric changes from hydrophobic to hydrophilic.

[0021] The present invention also provides an application of the Janus structure photothermal fabric with adjustable wettability in a solar evaporator, wherein the solar evaporator comprises the Janus structure photothermal fabric with adjustable wettability, polystyrene foam and a dust-free cloth; the dust-free cloth wraps the polystyrene foam, and the hydrophilic layer of the Janus structure photothermal fabric with adjustable wettability is arranged on the polystyrene foam wrapped by the dust-free cloth.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] On one hand, the present invention provides a Janus structure photothermal fabric with adjustable wettability. The photothermal fabric is based on a hydrophobic carbon fiber fabric. The photothermal fabric includes a hydrophilic layer and a hydrophobic layer located on both surfaces of the Janus structure photothermal fabric, respectively. The hydrophilic layer is a deposited CuS layer, and the hydrophobic layer is an undeposited CuS layer. The CuS nanosheets on the surface of the deposited CuS layer of the hydrophobic carbon fiber fabric are intertwined and connected to form abundant radial channels, which can serve as a bottom hydrophilic microchannel capillary water transport layer. The hydrophobic carbon fiber fabric without a copper layer, that is, the hydrophobic layer, serves as the top photothermal layer and still maintains hydrophobicity.

[0024] On the other hand, the present invention provides a method for preparing a Janus structure photothermal fabric with controllable wettability. A copper layer is deposited on a hydrophobic carbon fiber fabric by magnetron sputtering to provide sites for subsequent chemical reactions, and CuS nanosheets are further grown on its surface to form a hydrophilic layer.

[0025] Furthermore, by adjusting the copper plating time to adjust the thickness of the bottom hydrophilic layer, different pores are formed to control the water content and water transfer rate, so that the solar interface evaporator has different water supply rates. Through wettability design to balance the water supply rate and heat transfer rate, efficient water supply and effective thermal management are achieved.

[0026] The present invention also provides, on the one hand, the above-mentioned Janus structure photothermal fabric with adjustable wettability for application in a solar evaporator, which consists of a top hydrophobic layer, a bottom hydrophilic layer, and a polystyrene foam hydrophilic channel wrapped with a dust-free cloth, wherein the bottom hydrophilic layer is located above the hydrophilic channel. The top hydrophobic layer can effectively prevent salt ions from entering the light absorption layer, and the radial hydrophilic channels formed by the bottom CuS nanosheets can enhance thermal positioning and speed up salt discharge. The polystyrene foam hydrophilic channel wrapped with a dust-free cloth is used to accelerate salt diffusion and reflux. By changing the wettability of the hydrophobic carbon fiber cloth, solar light absorption and water evaporation are separated, eliminating the functional interference of the two that destroy each other, and allowing the two to be adjusted separately. The Janus structure evaporator can prevent salt deposition while ensuring the high evaporation performance and long-term stability of the evaporator. Compared with traditional solar evaporators, this evaporator limits the water transmission channel to the evaporator surface, while ensuring sufficient water supply, reducing the contact area between water and the photothermal layer, thereby reducing heat loss and increasing the evaporation rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a Janus structured photothermal fabric with adjustable wettability provided by the present invention being applied to a solar evaporator;

[0028] Figure 2 Figures a and b are SEM images of the bottom hydrophilic layer of the Janus structure photothermal fabric with adjustable wettability obtained in Example 1 of the present invention. Figure 2 Figures c and d are SEM images of the hydrophobic layer on the top surface of the Janus structure photothermal fabric with adjustable wettability in the present invention;

[0029] Figure 3 Schematic diagram of the evaporation rate of the Janus structure photothermal fabric with adjustable wettability prepared in Example 1 of the present invention in salt water and the evaporation rate of pure salt water;

[0030] Figure 4 This is a test graph of the water contact angle of the hydrophilic layer of the Janus structure photothermal fabric with adjustable wettability prepared in Examples 1 to 4 of the present invention;

[0031] Figure 5 Schematic diagram of surface salt deposition of the Janus structure photothermal fabric evaporator with adjustable wettability prepared in Example 7 of the present invention during continuous evaporation in high-concentration salt water for 7 hours. DETAILED DESCRIPTION

[0032] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0033] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0034] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0035] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0036] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0037] The present invention provides a Janus structure photothermal fabric with adjustable wettability, a preparation method thereof, and an application thereof.

[0038] On the one hand, the present invention provides a Janus structure photothermal fabric with adjustable wettability. The Janus structure photothermal fabric with adjustable wettability is based on a hydrophobic carbon fiber fabric. One side of the hydrophobic carbon fiber fabric is a hydrophilic layer, and the other side is a hydrophobic layer. The hydrophilic layer is a deposited CuS layer, and the hydrophobic layer is an undeposited CuS layer.

[0039] Specifically, the Janus-structured photothermal fabric with adjustable wettability is constructed based on a hydrophobic carbon fiber fabric, with two sides designed as a hydrophilic layer and a hydrophobic layer. The hydrophilic layer is created by depositing CuS, while the hydrophobic layer retains the original undeposited CuS state of the carbon fiber. The hydrophilic layer is formed by interlacing CuS nanosheets grown on the surface of the hydrophobic carbon fiber fabric to form a hydrophilic layer with radial pores.

[0040] The hydrophilic layer is composed of CuS nanosheets grown on the surface of the hydrophobic carbon fiber fabric, which are intertwined and connected with each other. These nanosheets form abundant radial pores, forming a hydrophilic layer with a microchannel structure, which promotes the transport of water by capillary action.

[0041] On the other hand, the present invention discloses a method for preparing a Janus structure photothermal fabric with controllable wettability, S1: After the hydrophobic carbon fiber fabric is cleaned, it is placed in a magnetron sputtering system, and argon is used as the sputtering gas to remove impurities on the surface of the hydrophobic carbon fiber fabric to obtain a clean hydrophobic carbon fiber fabric; for the Cu target, a pre-sputtering treatment is performed to remove the oxide layer on the copper surface to obtain a Cu target without a surface oxide layer.

[0042] S2: A Cu target is sputtered on the surface of a clean hydrophobic carbon fiber fabric using a DC power supply to obtain a hydrophobic carbon fiber fabric with a single-sided Cu layer deposited thereon; polyethylene glycol and deionized water are used as solvents, sodium hydroxide and sulfur powder are dissolved in the solvent to obtain a yellow mixed solution.

[0043] S3: The hydrophobic carbon fiber fabric with a single-sided Cu layer was immersed in a yellow mixed solution, and the copper sulfide layer was grown by reaction. After rinsing and drying, a Janus structure photothermal fabric with controllable wettability was obtained.

[0044] In one embodiment, argon is used as a sputtering gas to remove impurities on the surface of the hydrophobic carbon fiber fabric. -3 Pa, introduce 50 sccm argon gas and bombard for 5-10 min; the bias voltage is 400 V and the gas pressure is 6 Pa.

[0045] In one implementation, a pre-sputtering treatment is performed on a Cu target with a purity of 99.99% to remove the oxide layer on the copper surface; under a vacuum degree of 0.6 Pa, the pre-sputtering power value is 80-100 W, and the pre-sputtering time is 5-10 min.

[0046] In one implementation process, a DC power supply is used to sputter a Cu target with a current of 0.3 A and a sputtering power of 80-100 W. The rotation speed of the clean hydrophobic carbon fiber fabric is 8-13 r / min. After the power is turned on, a glow discharge occurs on the surface of the Cu target, and the sputtering time is 30-80 min.

[0047] In one implementation process, the mass ratio of sodium hydroxide and sulfur powder is 2-3:1, and the volume ratio of polyethylene glycol and deionized water is 1-2:15; specifically, 600 mg of sodium hydroxide particles, 200 mg or 300 mg of sulfur powder, and 1 mL or 2 mL of polyethylene glycol are weighed, 15 mL of deionized water is added, and the mixture is heated and stirred at 60-70° C. for 15-20 minutes to obtain a yellow mixed solution, in which sodium sulfide solution is present.

[0048] In one implementation, the yellow mixed solution is cooled to 20-25° C., a hydrophobic carbon fiber fabric with a single-sided Cu layer is immersed in the solution, reacted for 2-3 minutes, rinsed 3-5 times with propanol and deionized water, and dried at 60-65° C. for 3-3.5 hours.

[0049] During the reaction growth process of the copper sulfide layer, the color of the surface of the hydrophobic carbon fiber fabric with the Cu layer deposited on one side changes from copper to black to generate a CuS layer, forming a hydrophobic carbon fiber fabric with the CuS layer deposited on one side, and the surface wettability of the hydrophobic carbon fiber fabric changes from hydrophobic to hydrophilic.

[0050] Specifically, the following steps are included:

[0051] 1. Cleaning the hydrophobic carbon fiber fabric substrate

[0052] First, cut the hydrophobic carbon fiber fabric into the required size (e.g., 3×3 cm), then rinse the surface with ethanol and deionized water 3-5 times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0053] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0054] The bottom surface of the hydrophobic carbon fiber fabric was copper-plated using a magnetron sputtering device. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, set the rotation speed of the sample stage to 8-13 r / min, and then introduce argon as the sputtering gas with a flux of 50 sccm. Bombard for 5-10 min in Ar plasma atmosphere to remove impurities on the hydrophobic carbon fiber fabric and improve the bonding strength between the coating and the fabric. The bias voltage is set to 400 V and the gas pressure is set to 6 Pa.

[0055] The vacuum pressure was then further adjusted to 0.6 Pa, and the pre-sputtering power was set to 80-100 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 5-10 minutes to remove the oxide layer on the copper surface and improve the purity of the coating.

[0056] Finally, the baffle is opened, and a DC power supply with a current of 0.3 A is applied to the Cu target surface, causing a glow discharge. The electric field deposits the sputtered particles onto the surface of the hydrophobic carbon fiber fabric substrate. The sputtering power is 80-100 W, and the sputtering time is 30-80 minutes.

[0057] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0058] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0059] First, add 600 mg of sodium hydroxide particles and 300 mg or 200 mg of sulfur powder to 1 mL or 2 mL of polyethylene glycol, then add 15 mL of deionized water, and magnetically stir at 60-70 °C for 15-20 min to obtain a yellow mixed solution.

[0060] Secondly, when the mixed solution is cooled to 20-25 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer is impregnated for 2-3 minutes. The Cu surface turns black and generates CuS to obtain the CB / CC@CuS photothermal fabric (CCS).

[0061] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol 3-5 times and dried at 60-65°C for 3-3.5 hours to obtain the CB / CC@CuS photothermal fabric with controllable wettability. One surface of the photothermal fabric, CB, was a hydrophobic surface, and the other surface, CC@CuS, was a hydrophilic surface.

[0062] On the one hand, the present invention provides a solar evaporator. The solar evaporator is prepared using a Janus structure photothermal fabric with adjustable wettability, comprising the Janus structure photothermal fabric with adjustable wettability, polystyrene foam and a dust-free cloth; the dust-free cloth wraps the polystyrene foam, and the hydrophilic layer of the Janus structure photothermal fabric with adjustable wettability is arranged on the polystyrene foam wrapped by the dust-free cloth.

[0063] The specific process of preparing a solar evaporator using the wettability-adjustable Janus structure photothermal fabric is as follows:

[0064] The polystyrene foam was cut into a circle with a diameter of 5 cm and wrapped with a dust-free cloth. The obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth, with the hydrophilic layer at the bottom and the hydrophobic layer at the top.

[0065] The above preparation process uses a hydrophobic carbon fiber fabric as a substrate, depositing a copper layer via magnetron sputtering to provide sites for subsequent chemical reactions. A yellow mixed solution is then prepared to further grow CuS nanosheets on its surface. The nanosheets on the surface of the hydrophobic carbon fiber fabric are interconnected to form abundant radial channels, which can serve as a hydrophilic microchannel capillary water transport layer at the bottom. The uncoated carbon fiber fabric serves as the top photothermal layer and remains hydrophobic. Compared to traditional solar evaporators, this evaporator restricts the water transport channel to the evaporator surface, ensuring sufficient water supply while reducing the contact area between water and the photothermal layer, thereby reducing heat loss and increasing the evaporation rate.

[0066] A Janus-structured photothermal fabric with adjustable wettability is used in a solar evaporator. It uses a hydrophobic carbon fiber fabric as a substrate, with a hydrophilic layer grown on its surface. By adjusting the thickness of the bottom hydrophilic layer to create different pores, the water content and water transfer rate are controlled, resulting in a solar interface evaporator with varying water supply rates. Wettability is engineered to balance the water supply rate and heat transfer rate, achieving efficient water supply and effective thermal management. The evaporator consists of a top hydrophobic layer, a bottom hydrophilic layer, and a polystyrene foam hydrophilic channel wrapped in a dust-free cloth. The top hydrophobic layer effectively prevents salt ions from entering the light-absorbing layer, while the radial hydrophilic channels formed by the bottom CuS nanosheets enhance thermal localization and accelerate salt removal. The polystyrene foam hydrophilic channel, wrapped in a dust-free cloth, accelerates salt diffusion and reflux. This Janus-structured evaporator prevents salt deposition while maintaining high evaporation performance and long-term stability.

[0067] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0068] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0069] Example 1:

[0070] 1. Cleaning the carbon fiber fabric substrate

[0071] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water three times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0072] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0073] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, the rotation speed of the sample stage was set to 13 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment in an Ar plasma atmosphere for 10 min to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0074] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 100 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 5 min to remove the oxide layer on the copper surface and improve the purity of the coating.

[0075] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A was applied to the Cu target surface, causing a glow discharge. The sputtered particles were deposited onto the substrate surface under the action of the electric field. The sputtering power was 100 W, and the sputtering time was 30 minutes.

[0076] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0077] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0078] First, 600 mg of sodium hydroxide particles and 300 mg of sulfur powder were added to 1 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 60 °C for 20 min to obtain a yellow mixed solution.

[0079] Secondly, after the mixed solution was cooled to 20 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 2 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0080] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol three times and dried at 60°C for 3 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface of the photothermal fabric was a hydrophobic layer, and the lower surface of CC@CuS was a hydrophilic layer.

[0081] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0082] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0083] Example 2:

[0084] 1. Cleaning the carbon fiber fabric substrate

[0085] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water five times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0086] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0087] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, the rotation speed of the sample stage was set to 13 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment in an Ar plasma atmosphere for 10 min to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0088] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 90 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 5 min to remove the oxide layer on the copper surface and improve the purity of the coating.

[0089] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A was applied to the Cu target surface, causing a glow discharge. The sputtered particles were deposited onto the substrate surface under the action of the electric field. The sputtering power was 90 W, and the sputtering time was 50 minutes.

[0090] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0091] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0092] First, 600 mg of sodium hydroxide particles and 300 mg of sulfur powder were added to 1 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 60 °C for 20 min to obtain a yellow mixed solution.

[0093] Secondly, when the mixed solution was cooled to 20 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 2 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0094] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol five times and dried at 60°C for 3 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface of the photothermal fabric was a hydrophobic layer, and the lower surface of the CC@CuS was a hydrophilic layer.

[0095] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0096] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0097] Example 3:

[0098] 1. Cleaning the carbon fiber fabric substrate

[0099] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water four times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0100] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0101] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, the rotation speed of the sample stage was set to 13 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment in an Ar plasma atmosphere for 10 min to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0102] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 80 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 10 min to remove the oxide layer on the copper surface and improve the purity of the coating.

[0103] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A was applied to the Cu target surface, causing a glow discharge. The sputtered particles were deposited onto the substrate surface under the action of the electric field. The sputtering power was 80 W, and the sputtering time was 70 minutes.

[0104] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0105] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0106] First, 600 mg of sodium hydroxide particles and 300 mg of sulfur powder were added to 1 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 70 °C for 20 min to obtain a yellow mixed solution.

[0107] Secondly, when the mixed solution was cooled to 25 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 3 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0108] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol four times and dried at 60°C for 3 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface of the photothermal fabric was a hydrophobic layer, and the lower surface of CC@CuS was a hydrophilic layer.

[0109] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0110] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0111] Example 4:

[0112] 1. Cleaning the carbon fiber fabric substrate

[0113] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water five times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0114] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0115] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, the rotation speed of the sample stage was set to 13 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment in an Ar plasma atmosphere for 10 min to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0116] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 80 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 10 min to remove the oxide layer on the copper surface and improve the purity of the coating.

[0117] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A was applied to the Cu target surface, causing a glow discharge. The sputtered particles were deposited onto the substrate surface under the action of the electric field. The sputtering power was 80 W, and the sputtering time was 80 minutes.

[0118] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0119] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0120] First, 600 mg of sodium hydroxide particles and 300 mg of sulfur powder were added to 1 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 70 °C for 20 min to obtain a yellow mixed solution.

[0121] Secondly, when the mixed solution was cooled to 25 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 3 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0122] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol five times and dried at 60°C for 3 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface of the photothermal fabric was a hydrophobic layer, and the lower surface of the CC@CuS was a hydrophilic layer.

[0123] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0124] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0125] Example 5:

[0126] 1. Cleaning the carbon fiber fabric substrate

[0127] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water three times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0128] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0129] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, the rotation speed of the sample stage was set to 13 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment for 8 min in an Ar plasma atmosphere to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0130] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 90 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 8 min to remove the oxide layer on the copper surface and improve the purity of the coating.

[0131] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A was applied to the Cu target surface, causing a glow discharge. The sputtered particles were deposited onto the substrate surface under the action of the electric field. The sputtering power was 90 W, and the sputtering time was 60 minutes.

[0132] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0133] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0134] First, 600 mg of sodium hydroxide particles and 300 mg of sulfur powder were added to 1 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 70 °C for 20 min to obtain a yellow mixed solution.

[0135] Secondly, when the mixed solution was cooled to 25 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 2 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0136] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol three times and dried at 60°C for 3 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface of the photothermal fabric was a hydrophobic layer, and the lower surface of CC@CuS was a hydrophilic layer.

[0137] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0138] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0139] Example 6:

[0140] 1. Cleaning the carbon fiber fabric substrate

[0141] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water four times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0142] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0143] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, the rotation speed of the sample stage was set to 13 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment for 8 min in an Ar plasma atmosphere to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0144] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 90 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 8 min to remove the oxide layer on the copper surface and improve the purity of the coating.

[0145] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A was applied to the Cu target surface, causing a glow discharge. The sputtered particles were deposited onto the substrate surface under the action of the electric field. The sputtering power was 90 W, and the sputtering time was 40 minutes.

[0146] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0147] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0148] First, 600 mg of sodium hydroxide particles and 300 mg of sulfur powder were added to 1 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 60 °C for 20 min to obtain a yellow mixed solution.

[0149] Secondly, after the mixed solution was cooled to 20 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 2 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0150] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol three times and dried at 60°C for 3 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface of the photothermal fabric was a hydrophobic layer, and the lower surface of CC@CuS was a hydrophilic layer.

[0151] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0152] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0153] Example 7:

[0154] 1. Cleaning the carbon fiber fabric substrate

[0155] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water three times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0156] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0157] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10-3 Pa, the rotation speed of the sample stage was set to 13 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment for 5 min in an Ar plasma atmosphere to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0158] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 100 W. Under these conditions, a Cu target with a purity of 99.99% was pre-sputtered for 5 min to remove the oxide layer on the copper surface and improve the purity of the coating.

[0159] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A initiated a glow discharge on the Cu target surface, depositing the sputtered particles onto the substrate surface under the action of the electric field. The sputtering power was 100 W, and the sputtering time was 65 minutes.

[0160] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0161] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0162] First, 600 mg of sodium hydroxide particles and 300 mg of sulfur powder were added to 1 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 70 °C for 20 min to obtain a yellow mixed solution.

[0163] Secondly, after the mixed solution was cooled to 20 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 3 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0164] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol five times and dried at 60°C for 3 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface of the photothermal fabric was a hydrophobic layer, and the lower surface of the CC@CuS was a hydrophilic layer.

[0165] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0166] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0167] Example 8:

[0168] 1. Cleaning the carbon fiber fabric substrate

[0169] First, cut the carbon fiber fabric into the required size (e.g., 3 × 3 cm), then rinse the surface with ethanol and deionized water three times, and use an ear suction bulb to blow away the dust on the fabric surface.

[0170] 2. CB / CC@Cu obtained by magnetron sputtering copper plating

[0171] The magnetron sputtering equipment was used to plate copper on the bottom surface of the carbon fiber fabric. The fabric was fixed to the sample stage at the top of the chamber, and the copper target was installed. The chamber was evacuated using a mechanical pump and a molecular pump to a vacuum degree of 1.8×10 -3 Pa, the rotation speed of the sample stage was set to 8 r / min, and then argon was introduced as the sputtering gas with a flux of 50 sccm. Impurities on the carbon fiber fabric were removed by bombardment for 5 min in an Ar plasma atmosphere to improve the bonding strength between the coating and the fabric. The bias voltage was set to 400 V and the gas pressure was set to 6 Pa.

[0172] Subsequently, the vacuum pressure was further adjusted to 0.6 Pa, and the pre-sputtering power was set to 100 W. Under this condition, a Cu target with a purity of 99.99% was pre-sputtered for 10 minutes to remove the oxide layer on the copper surface and improve the purity of the coating.

[0173] Finally, the shutter was opened, and a DC power supply with a current of 0.3 A initiated a glow discharge on the Cu target surface, depositing the sputtered particles onto the substrate surface under the action of the electric field. The sputtering power was 100 W, and the sputtering time was 65 minutes.

[0174] After the above steps, the CB / CC@Cu photothermal fabric with a single-sided copper layer was obtained.

[0175] 3. Preparation of CB / CC@CuS photothermal fabrics with controllable wettability through chemical reaction

[0176] First, 600 mg of sodium hydroxide particles and 200 mg of sulfur powder were added to 2 mL of polyethylene glycol, and then 15 mL of deionized water was added. The mixture was magnetically stirred at 70 °C for 15 min to obtain a yellow mixed solution.

[0177] Secondly, after the mixed solution was cooled to 20 ℃, the CB / CC@Cu carbon fiber photothermal fabric with a single-sided Cu layer was impregnated and reacted for 3 min. After the Cu surface turned black, the CB / CC@CuS photothermal fabric (CCS) was obtained.

[0178] Finally, the CB / CC@CuS photothermal fabric was washed with deionized water and propanol five times and dried at 65°C for 3.5 h to obtain the CB / CC@CuS photothermal fabric with controllable wettability. The upper surface CB of the photothermal fabric was a hydrophobic layer, and the lower surface CC@CuS was a hydrophilic layer.

[0179] This embodiment also provides a solar evaporator using the Janus structure photothermal fabric with adjustable wettability. The solar evaporator includes the Janus structure photothermal fabric with adjustable wettability, polystyrene foam, and a dust-free cloth.

[0180] The polystyrene foam was cut into a circle with a diameter of 5 cm, wrapped with a dust-free cloth, and the obtained wettability-adjustable CB / CC@CuS photothermal fabric was placed on the dust-free cloth.

[0181] In order to eliminate the inevitable mutual influence caused by the coexistence of light absorption and water transmission in the same space in traditional super hydrophilic evaporators, Figure 1 A schematic diagram of a Janus-structured photothermal fabric with adjustable wettability applied to a solar evaporator is shown. The evaporator consists of a top hydrophobic layer, a bottom 2D water supply channel, and a hydrophilic layer formed by radial pores. The top hydrophobic layer enables efficient light absorption and salt resistance, the bottom water supply channel enhances thermal positioning and accelerates salt removal, and the hydrophilic layer formed by the radial pores is used to accelerate the diffusion and backflow of salt ions. By adjusting the thickness of the hydrophilic layer, the water content delivered to the interior or surface of the photothermal material can be matched to the input energy. At the same time, the backflow of salt ions in the hydrophilic layer of the Janus membrane can be achieved. This not only prevents solar energy from being used to heat too much water, but also effectively prevents the negative impact of salt crystallization on the evaporator, thereby greatly improving the evaporation efficiency and long-term stability of the evaporator.

[0182] Figure 2 Figures a and b are SEM images of the hydrophilic layer on the bottom surface of the Janus structure photothermal fabric with adjustable wettability obtained in Example 1 of the present invention. Figure 2 Figures c and d are SEM images of the hydrophobic layer on the top surface of the Janus structure photothermal fabric with adjustable wettability in the present invention. Figure 2 The hydrophobic carbon fiber fabric is woven from crisscross carbon fibers with a smooth fiber surface. The CC / CuS hydrophilic layer is obtained through a series of physical and chemical reactions. Figure 2 As shown in b, a large number of microscopic pore structures of varying sizes can be observed inside. The presence of these radial micropore structures significantly increases the capillary water transmission velocity, which is beneficial to the transmission, diffusion and reflux of solutes. Figure 2 From c and d, it can be seen that the surface of the hydrophobic carbon fiber fabric contains a large amount of carbon black (CB) particles, which increases the specific surface area of ​​the hydrophobic layer and thus improves the light absorption efficiency.

[0183] Figure 3 This figure shows the evaporation rate of the Janus structured photothermal fabric with adjustable wettability, as prepared in Example 1 of the present invention, in salt water and the evaporation rate of pure salt water. As can be seen from the figure, the Janus structured photothermal fabric with adjustable wettability, as an evaporator, can achieve an evaporation rate of 1.97 kg·m for a 3.5wt% NaCl solution under one sun. -2 ·h -1 , compared with pure salt water (0.84 kg·m -2 ·h -1 ) and untreated carbon fiber fabric (1.75 kg·m -2 ·h -1 ) were increased by 2.4 and 1.2 times, respectively, proving that the evaporator has good light-to-heat conversion performance and water transport performance.

[0184] Figure 4 The following graphs show the water contact angle measurements of the hydrophilic layer of the Janus-structured photothermal fabrics with adjustable wettability, as prepared in Examples 1-4 of the present invention. As shown in the graphs, 50 µL of water droplets were dropped onto the hydrophilic layer of each of the fabrics with adjustable wettability, and complete absorption took place after 2920 ms, 2260 ms, 1880 ms, and 410 ms, respectively, for CCS-1, CCS-2, CCS-3, and CCS-4, demonstrating the adjustable wettability of the resulting Janus-structured carbon fiber photothermal fabrics.

[0185] Figure 5 This figure shows the surface salt deposition of a Janus-structured photothermal fabric evaporator with adjustable wettability, produced in Example 7 of the present invention, after 7 hours of continuous evaporation in a high-concentration salt solution. As shown, at one sun intensity, the Janus-structured photothermal fabric evaporator exhibited a stable evaporation rate after 7 hours of continuous operation in a 25wt% NaCl solution. Only a small amount of salt crystallization appeared at the evaporator's edges, with no significant effect on the evaporator's light absorption or vapor outflow, demonstrating the evaporator's excellent salt tolerance and long-term stability.

[0186] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A Janus structure photothermal fabric with adjustable wettability, characterized in that: The Janus structure photothermal fabric with adjustable wettability is based on a hydrophobic carbon fiber fabric, one side of the hydrophobic carbon fiber fabric is a hydrophilic layer, and the other side is a hydrophobic layer, the hydrophilic layer is a deposited CuS layer, and the hydrophobic layer is an undeposited CuS layer.

2. The Janus structured photothermal fabric with adjustable wettability according to claim 1, characterized in that: The hydrophilic layer is a hydrophilic layer with radial pores formed by interlacing and connecting CuS nanosheets grown on the surface of the hydrophobic carbon fiber fabric.

3. A method for preparing the Janus structured photothermal fabric with controllable wettability according to any one of claims 1 to 2, characterized in that: The following steps are involved: After cleaning, the hydrophobic carbon fiber fabric is placed in a magnetron sputtering system. Argon is used as the sputtering gas to remove impurities on the surface of the hydrophobic carbon fiber fabric to obtain a clean hydrophobic carbon fiber fabric. For the Cu target, a pre-sputtering treatment is performed to remove the oxide layer on the copper surface to obtain a Cu target without a surface oxide layer. A Cu target is sputtered on the surface of a clean hydrophobic carbon fiber fabric using a DC power supply to obtain a hydrophobic carbon fiber fabric with a Cu layer deposited on one side; sodium hydroxide and sulfur powder are dissolved in polyethylene glycol and deionized water as solvents to obtain a yellow mixed solution; The hydrophobic carbon fiber fabric with a Cu layer deposited on one side was immersed in a yellow mixed solution, and the copper sulfide layer was grown by reaction, then rinsed and dried to obtain a Janus structure photothermal fabric with controllable wettability.

4. The method for preparing the Janus structured photothermal fabric with adjustable wettability according to claim 3, characterized in that: The process of using argon as a sputtering gas to remove impurities on the surface of the hydrophobic carbon fiber fabric is as follows: The high vacuum state in the chamber is 1.8×10 -3 Pa, 50 sccm of argon was introduced, the pressure was increased to 6 Pa, a bias of 400 V was applied, and the bombardment was carried out for 5-10 min.

5. The method for preparing the Janus structured photothermal fabric with adjustable wettability according to claim 3, wherein: The pre-sputtering treatment is performed under a vacuum degree of 0.6 Pa, the pre-sputtering power value is 80-100 W, and the pre-sputtering time is 5-10 min.

6. The method for preparing the Janus structured photothermal fabric with controllable wettability according to claim 3, wherein: The current when sputtering the Cu target through a DC power supply is 0.3 A, the sputtering power is 80-100 W, the rotation speed of the clean hydrophobic carbon fiber fabric is 8-13 r / min, and after starting the power supply, the Cu target surface is glowed and discharged, and the sputtering time is 30-80 minutes.

7. The method for preparing the Janus structured photothermal fabric with adjustable wettability according to claim 3, characterized in that: The mass ratio of the sodium hydroxide to the sulfur powder is 2-3:1; the volume ratio of the polyethylene glycol to the deionized water is 1-2:

15.

8. The method for preparing the Janus structured photothermal fabric with adjustable wettability according to claim 3, characterized in that: The dissolution is carried out by stirring and dissolving at a temperature of 60-70° C., and the stirring and dissolving time is 15-20 minutes; During the immersion, the temperature of the yellow mixed solution is 20-25° C., and the reaction time is 2-3 minutes; the rinsing is performed using propanol and deionized water, and the number of rinsing times is 3-5 times; the drying temperature is 60-65° C., and the drying time is 3-3.5 hours.

9. The method for preparing the Janus structured photothermal fabric with adjustable wettability according to claim 3, characterized in that: During the reaction growth process of the copper sulfide layer, the color of the surface of the hydrophobic carbon fiber fabric with the Cu layer deposited on one side changes from copper to black to generate a CuS layer, forming a hydrophobic carbon fiber fabric with the CuS layer deposited on one side, and the surface wettability of the hydrophobic carbon fiber fabric changes from hydrophobic to hydrophilic.

10. Application of the Janus structured photothermal fabric with adjustable wettability according to any one of claims 1 to 2 in a solar evaporator, characterized in that: The solar evaporator comprises a Janus structure photothermal fabric with adjustable wettability, polystyrene foam and a dust-free cloth; the dust-free cloth wraps the polystyrene foam, and the hydrophilic layer of the Janus structure photothermal fabric with adjustable wettability is arranged on the polystyrene foam wrapped by the dust-free cloth.

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