A 3D-printed hollowed-out cone-shaped solar interface evaporator with directional salt formation function, its preparation method and application

Abstract

This invention relates to the field of materials technology, and more particularly to a 3D-printed, internally hollowed-cone solar interface evaporator with directional salt deposition function, its preparation method, and its application. The invention includes step 1: three-dimensional model construction; step 2: substrate surface pretreatment and chemical activation; and step 3: hydrothermal preparation of a Co-Bi-S coating. This invention uses a 3D-printed porous, internally hollowed-cone resin device as a substrate, and grows a Co-Bi-S coating in situ on its surface using a hydrothermal method. This coating exhibits both excellent photothermal conversion performance and corrosion resistance. The evaporator structure is designed as a porous, internally hollowed-cone shape, which provides a larger evaporation area, stronger light capture and focusing capabilities, and can achieve higher evaporation temperatures and directional salt deposition effects. The prepared solar interface evaporator exhibits excellent photothermal conversion performance and water evaporation efficiency, and also demonstrates good structural stability and corrosion resistance. This solves the technical problems of low photothermal conversion efficiency and poor stability in high-salt environments inherent in traditional solar evaporators, making it suitable for applications such as seawater desalination.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a 3D-printed hollowed-out cone-shaped solar interface evaporator with directional salt formation function, its preparation method and application. Background Technology

[0003] Seawater desalination is a key technology for alleviating the freshwater shortage crisis, but traditional technologies such as reverse osmosis and distillation have limitations such as high energy consumption, reliance on centralized infrastructure and fossil fuels, and high operating costs. Solar interfacial evaporation technology has emerged as a green alternative. It achieves water evaporation through local photothermal conversion at the gas-liquid interface, significantly reducing energy loss. It also has the advantages of low energy consumption, distributed deployment, and higher mass transfer efficiency, making it particularly suitable for remote areas far from grid connections.

[0004] However, existing solar interface evaporators still face several core technological bottlenecks: First, traditional planar or simple three-dimensional structures have limited light-harvesting capabilities, generally low photothermal conversion efficiency, and heat is easily lost to the environment, limiting evaporation performance; Second, traditional evaporators have poor structural stability in high-salinity environments, and the substrate and coating are easily degraded and fail due to corrosion by corrosive media, and cannot achieve directional salt formation, with salt easily crystallizing and precipitating at the evaporation interface to form a salt crust, blocking the water supply channel and further reducing photothermal conversion and evaporation efficiency; Third, the long-term reliability of the system is insufficient, and the operation and maintenance costs remain high.

[0005] To address the aforementioned issues, this application provides a 3D-printed hollowed-out cone-shaped solar interface evaporator with directional salt formation function, its preparation method, and its application. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a 3D-printed conical solar interface evaporator with directional salt deposition function, its preparation method, and its application. The invention employs a synergistic design of a Co-Bi-S coating and a conical structure. The Co-Bi-S coating possesses excellent corrosion resistance and structural stability, enabling long-term stable operation in high-salt corrosion environments. The 3D-printed conical structure not only increases the number of light capture and reflections and reduces light escape loss through the optical effect of the concave curved surface, but also optimizes the thermal localization effect to reduce heat loss to the environment, significantly improving photothermal conversion efficiency. Simultaneously, it achieves spatial separation between the evaporation and crystallization regions, enabling efficient directional salt deposition and salt recovery, and greatly improving the long-term operational reliability of the system.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a 3D-printed conical solar interface evaporator with directional salt formation function, comprising the following steps:

[0008] Step 1: 3D Model Construction: The 3D structure design of the inward-curving conical solar interface evaporator was completed using SolidWorks software; the completed 3D model file was imported into a photopolymerization 3D printer, and the substrate device was fabricated through photopolymerization molding process.

[0009] Step 2, Substrate Surface Pretreatment and Chemical Activation: The 3D printed substrate device is ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface.

[0010] Step 3: Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complex solution and hydrothermal deposition reaction: The pretreated substrate device is placed in the above pretreatment complex solution and reacted in a 90 ℃ water bath for 2 h; After the reaction is completed, the device is taken out and rinsed repeatedly with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0011] Preferably, in step 1, the inner conical solar interface evaporator has an overall cylindrical structure with a height of 40mm and a radius of 15mm; its inner conical height is 10-40mm, and the diameter of the surface through hole is 0.5mm.

[0012] Preferably, step 2 further includes etching modification: immersing the cleaned substrate in a 4 M potassium hydroxide solution for 6 h for etching, followed by rinsing with deionized water until neutral; oxidation treatment: immersing the substrate in a 5% potassium permanganate solution for 20 min, then rinsing it with deionized water.

[0013] Preferably, step 2 further includes sensitization and activation: the substrate is sequentially immersed in a dimethylamine borane (DMAB) alkaline solution for 10 min, then in a 5% (w / w) tetraamminepalladium sulfate solution at 50 °C for 1 h, and thoroughly rinsed with deionized water after each treatment; finally, it is immersed in a DMAB alkaline solution again for 10 min and rinsed.

[0014] Preferably, step 2 further includes electroless nickel plating: preparing plating solution A and plating solution B, mixing equal volumes of solutions A and B, immersing the substrate in the mixed plating solution, reacting in a 70 ℃ water bath for 1.5 h, and rinsing with deionized water until neutral after the reaction is completed.

[0015] Preferably, the dimethylamine borane DMAB alkaline solution is a mixed solution containing 0.9 g / L DMAB and 4.6 g / L KOH.

[0016] Preferably, plating solution A comprises: 2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and diluted to 50 mL; plating solution B comprises: 1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and diluted to 50 mL.

[0017] Preferably, in step 3, the preparation of the pretreatment complexing solution includes: dissolving 3.77 g of sodium citrate in 100 mL of deionized water and stirring until completely dissolved; weighing 0.165–0.66 g of bismuth sulfate and dissolving it in 1 mL of 5% sulfuric acid solution, adding it dropwise to the sodium citrate solution, then adding 1.75 g of cobalt sulfate and stirring thoroughly until completely dissolved; then adding 6.2 g of sodium thiosulfate and continuing to stir until completely dissolved.

[0018] A 3D-printed hollowed-out cone-shaped solar interface evaporator with directional salt formation function obtained by the above preparation method.

[0019] The present invention also provides an application of the above-mentioned 3D-printed hollowed-out conical solar interface evaporator with directional salt formation function in seawater desalination.

[0020] By adopting the above technical solution, an innovative synergistic design of Co-Bi-S coating and hollow conical structure is used. The Co-Bi-S coating has excellent corrosion resistance and structural stability, and can be stably used for a long time in high salt corrosion environment. The 3D printed hollow conical structure can not only increase the number of light capture and reflection and reduce light escape loss through the optical effect of the concave curved surface, but also optimize the thermal localization effect to reduce heat loss to the environment, significantly improve the photothermal conversion efficiency, and realize the spatial separation of the evaporation area and the crystallization area, achieving efficient directional salt formation and salt recovery, and greatly improving the long-term operational reliability of the system.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention utilizes 3D printing technology to precisely fabricate an inwardly conical porous structure. This structure can increase the effective evaporation area, while increasing the number of light capture and reflection times and reducing light escape loss through the optical effect of the concave curved surface. It also optimizes the thermal localization effect to reduce heat loss to the environment, significantly improving the photothermal conversion efficiency and water evaporation efficiency, thus solving the technical pain point of low photothermal conversion efficiency in traditional evaporators.

[0023] 2. This invention can achieve efficient directional salt formation: the internal conical porous structure can optimize the water transport path and steam diffusion, realize the spatial separation of the evaporation area and the crystallization area, achieve efficient directional salt formation and salt recovery, avoid salt deposition at the evaporation interface to form a salt crust, and improve the salt resistance of the system from the structural level.

[0024] 3. The present invention has good stability and corrosion resistance: The Co-Bi-S coating grown in situ in the present invention has excellent corrosion resistance and structural stability, which can effectively resist the erosion of corrosive media in high salt water, avoid degradation and failure of the substrate and coating, enable the evaporator to operate stably for a long time in a high salt corrosion environment, and greatly improve the long-term operational reliability of the system.

[0025] 4. The preparation method of the present invention is simple and highly controllable. 3D printing technology can accurately realize the integrated molding of the internally hollowed conical porous structure, which is suitable for large-scale preparation and practical application. Attached Figure Description

[0026] Figure 1 This is a model diagram of the 3D-printed hollowed-out cone-shaped solar interface evaporator with high salt resistance according to the present invention;

[0027] Figure 2 The diagram shows the salt deposition of the evaporator with a 10mm internal cavity in 3.5% and 20% brine, respectively; where the internal cavity is 10mm, meaning it is submerged by 10mm.

[0028] Figure 3 The diagram shows the salt deposition in 3.5% and 20% brine for the evaporator with a 20mm internal cavity of the present invention; wherein, the internal cavity is 20mm, and the evaporator is submerged by 10mm.

[0029] Figure 4 The diagram shows the salt deposition in 3.5% and 20% brine for the evaporator with a 30mm internal cavity of the present invention; wherein, the internal cavity is 30mm, and the evaporator is submerged by 10mm.

[0030] Figure 5 The diagram shows the salt deposition in 3.5% and 20% brine for the evaporator with a 40mm internal cavity of the present invention; wherein, the internal cavity is 40mm, and the evaporator is submerged by 10mm.

[0031] Figure 6 The figure shows the heating results of samples with different bismuth contents in this invention. (a) contains no Bi, (b) contains 0.165 Bi, (c) contains 0.33 Bi, (d) contains 0.495 Bi, and (e) contains 0.66 Bi.

[0032] Figure 7 The polarization curves and electrochemical impedance spectroscopy are for the corrosion resistance test of the samples of this invention. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] This invention designs a solar interface evaporator with an internally hollowed-out conical porous structure. To further illustrate this invention, a model with an internal hollowing depth of 10-40 mm and a Co-Bi-S coating with a bismuth content of 0.165-0.66 g are used as examples for detailed description in conjunction with preferred embodiments.

[0035] Comparative Example 1

[0036] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0037] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 30mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0038] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0039] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0040] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0041] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g of sodium citrate in 100 mL of deionized water and stir until completely dissolved; weigh 0.33 g of bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g of cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g of sodium thiosulfate and continue stirring until completely dissolved.

[0042] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0043] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0044] Example 2

[0045] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0046] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 10mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0047] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0048] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0049] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0050] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g of sodium citrate in 100 mL of deionized water and stir until completely dissolved; weigh 0.33 g of bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g of cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g of sodium thiosulfate and continue stirring until completely dissolved.

[0051] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0052] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0053] Example 3

[0054] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0055] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 20mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0056] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0057] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0058] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0059] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g of sodium citrate in 100 mL of deionized water and stir until completely dissolved; weigh 0.33 g of bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g of cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g of sodium thiosulfate and continue stirring until completely dissolved.

[0060] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0061] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0062] Example 4

[0063] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0064] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 40mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0065] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0066] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0067] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0068] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g of sodium citrate in 100 mL of deionized water and stir until completely dissolved; weigh 0.33 g of bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g of cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g of sodium thiosulfate and continue stirring until completely dissolved.

[0069] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0070] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0071] Example 5

[0072] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0073] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 30mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0074] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0075] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0076] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0077] (4) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complex solution: Dissolve 3.77 g sodium citrate in 100 mL deionized water and stir until completely dissolved; add 1.75 g cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g sodium thiosulfate and continue stirring until completely dissolved.

[0078] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0079] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0080] Example 6

[0081] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0082] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 30mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0083] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0084] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0085] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0086] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g sodium citrate in 100 mL deionized water and stir until completely dissolved; weigh 0.165 g bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g sodium thiosulfate and continue stirring until completely dissolved.

[0087] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0088] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0089] Example 7

[0090] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0091] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 30mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0092] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0093] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0094] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0095] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g sodium citrate in 100 mL deionized water and stir until completely dissolved; weigh 0.495 g bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g sodium thiosulfate and continue stirring until completely dissolved.

[0096] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0097] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0098] Example 8

[0099] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0100] (1) 3D Model Construction: The 3D structure design of the hollowed-out conical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the hollowed-out conical part has a height of 30mm. The diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated using a photopolymerization molding process.

[0101] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0102] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0103] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0104] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g sodium citrate in 100 mL deionized water and stir until completely dissolved; weigh 0.66 g bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g sodium thiosulfate and continue stirring until completely dissolved.

[0105] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0106] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight, and the test results are shown in Tables 1 and 2.

[0107] Example 9

[0108] A method for fabricating a 3D-printed inward-facing conical solar interface evaporator with directional salt deposition function includes the following steps:

[0109] (1) 3D model construction: The 3D structure design of the flat cylindrical solar interface evaporator was completed using SolidWorks software. The device is cylindrical with a height of 40mm and a radius of 15mm; the diameter of the through hole on the device surface is 0.5mm. The completed 3D model file was imported into a photopolymer 3D printer, and the substrate device was fabricated through a photopolymerization molding process.

[0110] (2) Substrate surface pretreatment and chemical activation: The 3D printed substrate device was ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Etching modification: The cleaned substrate was immersed in 4 M potassium hydroxide solution for 6 h for etching, and then rinsed with deionized water until neutral. Oxidation treatment: The substrate was immersed in 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

[0111] Sensitization and activation: The substrate was sequentially immersed in an alkaline solution of dimethylamine borane (DMAB) (containing 0.9 g / L DMAB and 4.6 g / L KOH) for 10 min, and then in a 5% tetraammonium palladium sulfate solution at 50 °C for 1 h. After each treatment, the substrate was thoroughly rinsed with deionized water. Finally, the substrate was immersed in an alkaline solution of DMAB for 10 min and then rinsed.

[0112] Electroless nickel plating: Prepare plating solution A (2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and bring the volume to 50 mL) and plating solution B (1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and bring the volume to 50 mL). Mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is complete, rinse with deionized water until neutral.

[0113] (3) Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complexing solution: Dissolve 3.77 g of sodium citrate in 100 mL of deionized water and stir until completely dissolved; weigh 0.33 g of bismuth sulfate and dissolve it in 1 mL of 5% sulfuric acid solution, add it dropwise to the sodium citrate solution, then add 1.75 g of cobalt sulfate and stir thoroughly until completely dissolved; then add 6.2 g of sodium thiosulfate and continue stirring until completely dissolved.

[0114] Hydrothermal deposition reaction: The pretreated substrate device is placed in the above mixed solution and reacted in a 90 ℃ water bath for 2 h. After the reaction is completed, the device is taken out and repeatedly rinsed with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

[0115] Through 100mw / cm 2 The evaporation efficiency of the evaporator was tested under simulated sunlight. The test results showed that the flat plate evaporator had no directional salt deposition ability in 3.5% brine, salt was easy to deposit at the evaporation interface, and the structure had poor stability.

[0116] Photothermal and evaporation performance testing

[0117] The photothermal properties (using a xenon lamp to simulate solar intensity for 8 hours) and evaporation rate (using 3.5% saline solution) of the devices in Cases 1-8 are as follows:

[0118] Table 1 shows the evaporation efficiency of seawater (3.5% brine) in Comparative Examples 1, Examples 2-8.

[0119]

[0120] Table 2 shows the evaporation efficiency of concentrated brine (20% brine) in Comparative Examples 1, Examples 2-8.

[0121]

[0122] Corrosion resistance test results and analysis

[0123] The Co-Bi-S multi-component sulfide coating possesses a stable layered crystal structure and strong covalent bonding. Its band structure between the valence and conduction bands endows the material with excellent chemical inertness, effectively resisting the adsorption and penetration of chloride ions in high-salinity waters and preventing substrate oxidation or pitting. Simultaneously, the passivation layer formed on the coating surface further hinders the contact between the corrosive medium and the substrate, thus maintaining long-term structural integrity in harsh environments such as high-salinity brine. To verify the corrosion resistance of the Co-Bi-S coating used in this invention and the structural stability of the evaporator, polarization curves (Tafel curves) and electrochemical impedance spectroscopy were performed in a simulated seawater environment (3.5 wt.% NaCl solution), with a bismuth-free Co-S coating used as a control. The test results are as follows: Figure 7 As shown.

[0124] Polarization curve (Tafel curve) analysis: As can be seen from the polarization curve, the corrosion current density (j) corresponding to the Co-Bi-S coating (red curve) of the present invention is... corr The corrosion potential (E) is significantly lower than that of the Co-S coating (black curve), and the corrosion potential (E) is also significantly lower. corr The corrosion current density decreases significantly, indicating a substantial reduction in the corrosion rate of the coating and effectively reducing corrosion loss of the substrate material. The positive shift in corrosion potential indicates that the Co-Bi-S coating is thermodynamically more corrosion-inert, which can inhibit the spontaneous occurrence of corrosion reactions and improve the structural stability of the evaporator at the material level.

[0125] Electrochemical impedance spectroscopy (Nyquist plot) analysis showed that the diameter of the Nyquist semicircle corresponding to the Co-Bi-S coating (red data points) was much larger than that of the Co-S coating (green data points), indicating its charge transfer resistance (Ro). ct The charge transfer resistance is significantly improved. Higher charge transfer resistance means that the coating can more effectively prevent corrosive media (such as chloride ions) from contacting the substrate, forming a denser barrier layer, thereby greatly inhibiting the corrosion process of the substrate and improving the long-term protective capability of the coating and the long-term operational stability of the evaporator.

[0126] Based on the combined polarization curves and electrochemical impedance spectroscopy results, the Co-Bi-S coating of this invention significantly outperforms the bismuth-free Co-S coating in key corrosion resistance indicators such as corrosion current density, corrosion potential, and charge transfer impedance, exhibiting superior corrosion resistance and structural stability. This coating provides reliable and long-term protection for solar interface evaporators in high-salt corrosive environments, effectively preventing substrate material degradation and structural failure. It ensures that the evaporator maintains high photothermal conversion efficiency and directional salt deposition in high-salt environments, laying a core material foundation for the long-term stable operation of the device.

[0127] Figures 2–5 (Schematic diagrams of salt formation behavior) Explanation:

[0128] Figure 2 (10mm inner cavitation): In 3.5% brine, after the evaporator has been running for 8–10 hours, the evaporation surface remains relatively clean with no obvious salt crust covering it. In 20% high-salt brine, the salt mainly crystallizes at the edges and in the inner cavitation area, and the salt crust adheres to the evaporation surface. This indicates that the 10mm inner cavitation structure has insufficient ability to directionally crystallize salt, and there is still room for improvement in salt management in high-salt environments.

[0129] Figure 3 (20mm inner scoop): Under 3.5% brine, there is no salt shell on the evaporation surface after the evaporator is running, and the salt mainly crystallizes at the edge; under 20% brine, the salt is concentrated at the edge and the inner scoop area, and the salt shell coverage is significantly reduced. The directional salt formation effect is better than the 10mm inner scoop structure, indicating that increasing the inner scoop depth helps to optimize the salt concentration field distribution.

[0130] Figure 4 (30mm inner cavitation): Under 3.5% brine, the evaporation surface is completely free of salt crust after the evaporator starts operating, with salt crystallizing entirely at the edges; under 20% brine, salt crystallizes only in a ring around the surface, and the crystallized salt can easily and freely fall off, keeping the evaporation surface clean at all times. This result proves that the 30mm inner cavitation design can effectively achieve spatial separation between the evaporation and crystallization areas, achieving efficient directional salt formation, avoiding salt crust blockage of the evaporation channel, and thus maintaining stable evaporation performance.

[0131] Figure 5 (40mm inner depth): Under 3.5% and 20% brine, salt mainly crystallizes at the edge, but a small amount of salt is still deposited on the evaporation surface. This indicates that excessive inner depth may affect capillary water transport efficiency, resulting in a slightly inferior directional salt formation effect compared to the 30mm inner depth structure. This suggests that there is an optimal inner depth range.

[0132] Figure 6 (Temperature curves of samples with different Bi contents) Explanation:

[0133] Figure 6 shows the heating behavior of Co-Bi-S coatings with different Bi contents under simulated sunlight:

[0134] The highest temperature of the Bi-free sample (a) was approximately 49.5 °C;

[0135] When the Bi content is 0.165g(b), the highest temperature increases to approximately 53.7℃;

[0136] When the Bi content was 0.33g (c), the highest temperature reached about 59.0℃, which was the highest among all samples; when the Bi content was further increased to 0.495g (d) and 0.66g (e), the highest temperature dropped slightly (about 56.1℃ and 56.4℃).

[0137] This result indicates that the introduction of an appropriate amount of Bi can optimize the light absorption and photothermal conversion performance of the coating. When the Bi content is 0.33g, the photothermal heating effect is optimal and the photothermal conversion efficiency reaches its peak. Excessive Bi may lead to material agglomeration or light absorption saturation, thereby weakening the photothermal performance.

[0138] In summary, the solar interface evaporator prepared by this invention has excellent photothermal conversion performance and water evaporation efficiency, as well as good structural stability and corrosion resistance. It solves the technical problems of low photothermal conversion efficiency and poor stability in high-salt environments of traditional solar evaporators, and is suitable for seawater desalination and other fields.

[0139] The descriptions and practices disclosed in this invention are readily apparent and understandable to those skilled in the art, and various modifications and refinements can be made without departing from the principles of this invention. Therefore, any modifications or improvements made without departing from the spirit of this invention should also be considered within the scope of protection of this invention.

Claims

1. A method for fabricating a 3D-printed internally shaped conical solar interface evaporator with directional salt deposition function, characterized in that, Includes the following steps: Step 1: 3D Model Construction: The 3D structure design of the inward-curving conical solar interface evaporator was completed using SolidWorks software; the completed 3D model file was imported into a photopolymerization 3D printer, and the substrate device was fabricated through photopolymerization molding process. Step 2, Substrate Surface Pretreatment and Chemical Activation: The 3D printed substrate device is ultrasonically cleaned three times with isopropanol and three times with deionized water to remove uncured resin and impurities from the surface. Step 3: Preparation of Co-Bi-S coating by hydrothermal method: Preparation of pretreatment complex solution and hydrothermal deposition reaction: The pretreated substrate device is placed in the above pretreatment complex solution and reacted in a 90 ℃ water bath for 2 h; After the reaction is completed, the device is taken out and rinsed repeatedly with deionized water to remove residual salts on the surface. Finally, it is placed in a vacuum drying oven to dry, and the target evaporator is obtained.

2. The method for preparing a 3D-printed conical solar interface evaporator with directional salt deposition function according to claim 1, characterized in that, In step 1, the inner conical solar interface evaporator has an overall cylindrical structure with a height of 40mm and a radius of 15mm; its inner conical height is 10-40mm, and the diameter of the surface through hole is 0.5mm.

3. The method for preparing a 3D-printed conical solar interface evaporator with directional salt deposition function according to claim 1, characterized in that, Step 2 also includes etching modification: the cleaned substrate is immersed in a 4 M potassium hydroxide solution for etching for 6 h, and then rinsed with deionized water until neutral; oxidation treatment: the substrate is immersed in a 5% potassium permanganate solution for 20 min, and then rinsed with deionized water.

4. The method for preparing a 3D-printed conical solar interface evaporator with directional salt deposition function according to claim 3, characterized in that, Step 2 also includes sensitization and activation: the substrate is successively immersed in a dimethylamine borane (DMAB) alkaline solution for 10 min, then in a 5% tetraamminepalladium sulfate solution at 50 °C for 1 h, and thoroughly rinsed with deionized water after each treatment; finally, it is immersed in a DMAB alkaline solution again for 10 min and rinsed.

5. The method for preparing a 3D-printed conical solar interface evaporator with directional salt deposition function according to claim 4, characterized in that, Step 2 also includes electroless nickel plating: prepare plating solution A and plating solution B, mix equal volumes of solutions A and B, immerse the substrate in the mixed plating solution, and react for 1.5 h in a 70 ℃ water bath. After the reaction is completed, rinse with deionized water until neutral.

6. The method for preparing a 3D-printed conical solar interface evaporator with directional salt deposition function according to claim 4, characterized in that, The dimethylamine borane DMAB alkaline solution is a mixed solution containing 0.9 g / L DMAB and 4.6 g / L KOH.

7. The method for preparing a 3D-printed conical solar interface evaporator with directional salt deposition function according to claim 5, characterized in that, Plating solution A consists of 2 g sodium citrate, 0.23 g potassium hydroxide, 2 g sodium tetraborate, and 1.5 g nickel sulfate dissolved in deionized water, and the volume is adjusted to 50 mL. Plating solution B consists of 1 g sodium hypophosphite and 0.23 g potassium hydroxide dissolved in deionized water, and the volume is adjusted to 50 mL.

8. The method for preparing a 3D-printed conical solar interface evaporator with directional salt deposition function according to claim 1, characterized in that, In step 3, the preparation of the pretreatment complexing solution includes: dissolving 3.77 g of sodium citrate in 100 mL of deionized water and stirring until completely dissolved; weighing 0.165–0.66 g of bismuth sulfate and dissolving it in 1 mL of 5% sulfuric acid solution, adding it dropwise to the sodium citrate solution, followed by adding 1.75 g of cobalt sulfate and stirring thoroughly until completely dissolved; then adding 6.2 g of sodium thiosulfate and continuing to stir until completely dissolved.

9. A 3D-printed hollowed-out cone-shaped solar interface evaporator with directional salt formation function, obtained by the preparation method according to any one of claims 1-8.

10. An application of a 3D-printed hollowed-out conical solar interface evaporator with directional salt-gathering function as described in claim 9 in seawater desalination.

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