A MoS2-PDA-NiPc(NH2)4-AB composite material, its preparation method and application

Abstract

The application belongs to the technical field of composite materials, and particularly relates to a MoS2-PDA-NiPc(NH2)4-AB composite material, a preparation method and application thereof. The preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material comprises the following steps: (1) a substrate with MoS2 nanosheet arrays attached to the surface is soaked in a mixed solution containing dopamine hydrochloride and acetylene black, and after soaking, drying is performed to obtain a MoS2-PDA-AB composite material; (2) the MoS2-PDA-AB composite material is placed in a four-amino nickel phthalocyanine solution, and a solvothermal reaction is performed; and (3) solid-liquid separation and drying are performed. The MoS2-PDA-NiPc(NH2)4-AB composite material has a more negative open circuit potential than MoS2, and has a higher photoelectric current density and photo-generated carrier separation efficiency and a lower charge transfer impedance.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a MoS2-PDA-NiPc(NH2)4-AB composite material, its preparation method, and its application. Background Technology

[0002] With the development of materials science and nanotechnology, composite materials based on transition metal sulfides have shown broad application prospects in fields such as electrocatalysis, sensing, biodetection, and environmental remediation. Among them, molybdenum disulfide (MoS2) has become a research hotspot due to its unique layered structure, abundant edge active sites, and excellent electrochemical performance. However, single MoS2 materials still suffer from poor conductivity, limited utilization of active sites, and insufficient structural stability, which restricts their further application.

[0003] To improve the properties of MoS2, researchers typically optimize performance by constructing composite materials. Although existing studies have reported various MoS2-based composite systems, problems such as uneven component distribution, insufficient interfacial bonding, and discontinuous electron transport paths still exist during the multi-component synergistic construction process. Furthermore, existing preparation methods are often complex and lack controllability, making it difficult to achieve synergistic optimization of structure and properties.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a MoS2-PDA-NiPc(NH2)4-AB composite material, its preparation method, and its application, so as to help solve or improve the problem that the photocathode protection effect of MoS2 needs to be improved.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a MoS2-PDA-NiPc(NH2)4-AB composite material, comprising the following steps: (1) immersing a substrate with a MoS2 nanosheet array attached to its surface in a mixed solution containing dopamine hydrochloride and acetylene black, and drying the substrate after immersion to obtain the MoS2-PDA-AB composite material; (2) placing the MoS2-PDA-AB composite material in a tetraaminonickel phthalocyanine solution for a solvothermal reaction; (3) after the solvothermal reaction, separating the solid and liquid, and drying the obtained solid to obtain the MoS2-PDA-NiPc(NH2)4-AB composite material.

[0007] Preferably, in step (1), the concentration of dopamine hydrochloride in the mixed solution is 0.5-3 mg / mL, and the concentration of acetylene black is 0.1-0.5 mg / mL; the pH of the mixed solution is 8-9; and the soaking time in step (1) is 0.5-3 h.

[0008] Preferably, in step (2), the temperature of the solvothermal reaction is 80-140℃ and the reaction time is 6-12h; in step (2), the concentration of the tetraaminonickel phthalocyanine solution is 0.2-0.5mg / mL.

[0009] Preferably, in step (1), the substrate with the MoS2 nanosheet array attached to its surface is prepared by a method including the following steps: A1, ... A1. Dissolve thiourea in deionized water and mix thoroughly to obtain a homogeneous precursor solution; A2. Place the substrate and the precursor solution into a polytetrafluoroethylene-lined reactor and perform a hydrothermal reaction at 180-200℃ for 12-18 hours; A3. After the reaction is completed, allow it to cool naturally, remove the reaction solution, clean and dry to obtain a substrate with a MoS2 nanosheet array attached to its surface.

[0010] Preferably, in step A1, The molar ratio of thiourea to thiourea is 1:5-1:12; the mixing method is magnetic stirring for 30-60 minutes and ultrasonication for 5-20 minutes; in step A3, deionized water and ethanol are used for cleaning; the drying temperature is 60-80℃.

[0011] Preferably, the tetraaminoniphthalocyanine in the tetraaminoniphthalocyanine solution is prepared by a method comprising the following steps: B1. Under nitrogen protection, nitrophthalonitrile and nickel acetate tetrahydrate are added to a reaction vessel in a molar ratio, DMF is added, and the mixture is heated to 160-180°C and refluxed for 8-12 hours with continuous stirring. After the reaction is completed, the mixture is cooled to room temperature, the solid product is collected by filtration, washed, and the tetranitroniphthalocyanine intermediate is obtained; B2. The tetranitroniphthalocyanine intermediate is dispersed in DMF, and under nitrogen protection, it is added to... Adjust the pH to 1-2 and stir the reaction at 70-80℃ for 4-6 hours; B3. After the reaction is complete, pour the reaction solution into deionized water, collect the precipitate, wash the precipitate to obtain tetraaminonickel phthalocyanine.

[0012] Preferably, in step B1, the molar ratio of nitrophthalonitrile to nickel acetate tetrahydrate is 4:1-5:1; in step B1, washing is performed sequentially with ethanol, deionized water, and acetone; in step B2, the tetranitronickel phthalocyanine intermediate and... The mass ratio is 1:5-1:15; in step B2, hydrochloric acid is used to adjust the pH; in step B3, water and ethanol are used for washing, followed by washing with an organic solvent.

[0013] The present invention also provides a MoS2-PDA-NiPc(NH2)4-AB composite material, which adopts the following technical solution: a MoS2-PDA-NiPc(NH2)4-AB composite material, wherein the MoS2-PDA-NiPc(NH2)4-AB composite material is prepared by the method described above.

[0014] The present invention also provides an application of the MoS2-PDA-NiPc(NH2)4-AB composite material, which adopts the following technical solution: the application of the MoS2-PDA-NiPc(NH2)4-AB composite material as described above in photocathode protection.

[0015] Beneficial effects: The MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention has a significantly more negative open circuit potential than MoS2, and its photocurrent density and photogenerated carrier separation efficiency are significantly higher, and its charge transfer impedance is significantly lower, thus providing better photocathode protection for 304 stainless steel. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 The graphs show the electrochemical performance test results of the composite materials of Example 1 (MoS2-PDA-NiPc(NH2)4-AB), Comparative Example 1 (MoS2), Comparative Example 2 (MoS2-PDA), Comparative Example 3 (MoS2-PDA-NiPc(NH2)4), and Comparative Example 4 (MoS2-PDA-AB); where (a) is the OCP test result graph and (b) is the it curve test result graph.

[0017] Figure 2 The graphs show the electrochemical performance test results of the MoS2-PDA-NiPc(NH2)4-AB composite materials prepared using NiPc(NH2)4 solutions of different concentrations in Example 1; where (a) is the it curve test result graph and (b) is the OCP test result graph.

[0018] Figure 3 The image shows the electrochemical impedance spectroscopy (EIS) results of the composite materials of Example 1 (MoS2-PDA-NiPc(NH2)4-AB), Comparative Example 1 (MoS2), Comparative Example 2 (MoS2-PDA), Comparative Example 3 (MoS2-PDA-NiPc(NH2)4), and Comparative Example 4 (MoS2-PDA-AB).

[0019] Figure 4 The image shows the UV-Vis diffuse reflectance spectra of the composite materials of Example 1 (MoS2-PDA-NiPc(NH2)4-AB), Comparative Example 1 (MoS2), Comparative Example 2 (MoS2-PDA), Comparative Example 3 (MoS2-PDA-NiPc(NH2)4), and Comparative Example 4 (MoS2-PDA-AB).

[0020] Figure 5 The figure shows the test results of the it curve of the MoS2-PDA-NiPc(NH2)4-AB composite material prepared by using mixed solutions with different acetylene black concentrations in Example 2.

[0021] Figure 6 The figure shows the OCP test results of the MoS2-PDA-NiPc(NH2)4-AB composite material prepared at different solvothermal reaction temperatures in Example 4. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0023] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0024] This invention addresses the issue of insufficient photocathode protection performance of MoS2 by providing a method for preparing a MoS2-PDA-NiPc(NH2)4-AB composite material.

[0025] The preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention includes the following steps: (1) Immersing a substrate with a MoS2 nanosheet array attached to its surface in a mixed solution (the substrate with the MoS2 nanosheet array attached to its surface can be located below the liquid surface of the mixed solution), the mixed solution contains dopamine hydrochloride and acetylene black, and drying after immersion to obtain the MoS2-PDA-AB composite material; (2) Placing the MoS2-PDA-AB composite material in a tetraaminonickel phthalocyanine solution for a solvothermal reaction; (3) After the solvothermal reaction is completed, the solid and liquid are separated, and the obtained solid is dried to obtain the MoS2-PDA-NiPc(NH2)4-AB composite material.

[0026] In a preferred embodiment of the method for preparing the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention, in step (1), the concentration of dopamine hydrochloride in the mixed solution is 0.5-3 mg / mL (e.g., 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL or 3 mg / mL), and the concentration of acetylene black is 0.1-0.5 mg / mL (e.g., 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL or 0.5 mg / mL); the pH of the mixed solution is 8-9 (e.g., 8, 8.2, 8.4, 8.6, 8.8 or 9); and the soaking time in step (1) is 0.5-3 h (e.g., 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h or 3 h).

[0027] In a preferred embodiment of the preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention, in step (2), the temperature of the solvothermal reaction is 80-140℃ (e.g., 80℃, 90℃, 100℃, 110℃, 120℃, 130℃ or 140℃), and the reaction time is 6-12h (e.g., 6h, 7h, 8h, 9h, 10h, 11h or 12h); the concentration of the tetraaminonickel phthalocyanine solution is 0.2-0.5mg / mL (e.g., 0.2mg / mL, 0.3mg / mL, 0.4mg / mL or 0.5mg / mL). The loading of tetraaminonickel phthalocyanine has a significant impact on the structure and photoelectric properties of the material. When the amount of NiPc(NH2)4 is too low, there are insufficient active sites, resulting in the ineffective consumption and transfer of photogenerated electrons. This increases the probability of electron-hole recombination, manifesting as lower photocurrent density, poor charge transfer efficiency, and limited negative shift in cathodic protection potential. Conversely, when the NiPc(NH2)4 loading is too high, it tends to aggregate or stack on the material surface, leading to enhanced π-π interactions but a reduction in effective active sites. This also weakens light absorption and reduces the photoexcitation efficiency of MoS2. This manifests as a decrease in photocurrent, an increase in electrochemical impedance, and a weakening of cathodic protection performance.

[0028] Preferably, in step (2), the MoS2-PDA-AB composite material attached to each FTO substrate (the FTO substrate has a length of 2cm, a width of 1cm, and a thickness of 2mm) is placed in 7mL of tetraaminonickel phthalocyanine solution.

[0029] In a preferred embodiment of the preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention, in step (1), the substrate with MoS2 nanosheet array attached to its surface is prepared by a method including the following steps: A1, ... A1. Dissolve thiourea in deionized water and mix thoroughly to obtain a homogeneous precursor solution; A2. Place the substrate and the precursor solution into a polytetrafluoroethylene-lined reactor (preferably, the volume of the precursor solution is controlled to be less than 80% of the reactor capacity), and perform a hydrothermal reaction at 180-200℃ (e.g., 180℃, 190℃ or 200℃) for 12-18h (e.g., 12h, 14h, 16h or 18h); A3. After the reaction is completed, allow it to cool naturally, remove the reaction solution, clean and dry to obtain a substrate with a MoS2 nanosheet array attached to its surface.

[0030] In a preferred embodiment of the preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention, in step A1, The molar ratio of thiourea to thiourea is 1:5-1:12 (e.g., 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11 or 1:12); the mixture is stirred magnetically for 30-60 min (e.g., 30 min, 40 min, 50 min or 60 min) and sonicated for 5-20 min (e.g., 5 min, 10 min, 15 min or 20 min); in step A3, the mixture is washed with deionized water and ethanol; the drying temperature is 60-80℃ (e.g., 60℃, 65℃, 70℃, 75℃ or 80℃).

[0031] In a preferred embodiment of the preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention, the tetraaminonickel phthalocyanine in the tetraaminonickel phthalocyanine solution is prepared by a method comprising the following steps: B1. Under nitrogen protection, nitrophthalonitrile and nickel acetate tetrahydrate are added to a reaction vessel in a molar ratio, DMF is added, and the mixture is heated to 160-180°C (e.g., 160°C, 170°C, or 180°C) with continuous stirring and refluxed for 8-12 h (e.g., 8 h, 9 h, 10 h, 11 h, or 12 h). After the reaction is completed, the mixture is cooled to room temperature, the solid product is collected by filtration, washed, and the tetranitronickel phthalocyanine intermediate is obtained; B2. The tetranitronickel phthalocyanine intermediate is dispersed in DMF, and under nitrogen protection, it is added to... Adjust the pH to 1-2 (e.g., 1, 1.2, 1.4, 1.6, 1.8 or 2), and stir the reaction at 70-80℃ (e.g., 70℃, 72℃, 74℃, 76℃, 78℃ or 80℃) for 4-6 hours (e.g., 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours); B3. After the stirring reaction is complete, pour the reaction solution into deionized water, collect the precipitate, and wash the precipitate to obtain tetraaminonickel phthalocyanine.

[0032] In a preferred embodiment of the preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention, in step B1, the molar ratio of nitrophthalonitrile to nickel acetate tetrahydrate is 4:1-5:1 (e.g., 4:1, 4.3:1, 4.5:1, 4.7:1 or 5:1); in step B1, the mixture is washed sequentially with ethanol, deionized water and acetone; in step B2, the tetranitronickel phthalocyanine intermediate and... The mass ratio is 1:5-1:15 (e.g., 1:5, 1:8, 1:10, 1:12 or 1:15); in step B2, hydrochloric acid is used to adjust the pH; in step B3, water and ethanol are used for washing, followed by washing with an organic solvent.

[0033] The present invention also proposes a MoS2-PDA-NiPc(NH2)4-AB composite material, which is prepared by the method described above in the embodiments of the present invention.

[0034] This invention also proposes an application of the MoS2-PDA-NiPc(NH2)4-AB composite material, as described above, in photocathode protection.

[0035] The following detailed description of the MoS2-PDA-NiPc(NH2)4-AB composite material of the present invention, its preparation method, and its application are illustrated by specific embodiments.

[0036] The main raw materials used in the following examples were sourced as follows: Dopamine hydrochloride (CAS: 62-31-7) was purchased from BASF Biotechnology Co., Ltd., Hefei; Acetylene black (CAS: 1333-86-4) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; NaOH (CAS: 1310-73-2) was purchased from Chengdu Kelong Chemical Co., Ltd.; FTO conductive glass was purchased from Liaoning Youxuan New Energy Technology Co., Ltd.; DMA (N,N-dimethylacetamide) (CAS: 127-19-5) was purchased from Tianjin Damao Chemical Reagent Factory; Thiourea (CAS: 62-56-6) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (CAS No.: 10102-40-6) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Nitrophthalonitrile (CAS No.: 31643-49-9) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Nickel acetate tetrahydrate (CAS No.: 6018-89-9) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; DMF (N,N-dimethylformamide) (CAS No.: 68-12-2) was purchased from Tianjin Damao Chemical Reagent Factory; Hydrochloric acid (CAS No.: 7647-01-0) was purchased from Chengdu Kelong Chemical Co., Ltd.; Anhydrous ethanol (CAS No.: 64-17-5) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (CAS No.: 10025-69-1) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Acetone (CAS No.: 67-64-1) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0037] Example 1 The MoS2-PDA-NiPc(NH2)4-AB composite material of this embodiment was prepared by a method including the following steps: (1) In an aqueous solution containing dopamine hydrochloride (concentration of 1 mg / mL) and acetylene black (concentration of 0.3 mg / mL), NaOH was used as a pH adjuster to make the pH 8.5 to obtain a mixed solution; (2) A piece of FTO substrate with MoS2 nanosheet array attached to its surface (the size of the FTO substrate is 2 cm long, 1 cm wide and 2 mm thick) was immersed in 60 mL of the above solution for 1 h, and then dried at 60 °C for 30 min to obtain MoS2-PDA-AB composite material. (3) Using DMA as a solvent, NiPc(NH2)4 was dissolved in a water bath at 60°C to obtain a NiPc(NH2)4 solution (the concentration of NiPc(NH2)4 was 0.2 mg / mL-0.5 mg / mL). An FTO substrate (one piece) with MoS2-PDA-AB composite material deposited on its surface was placed in 7 mL of NiPc(NH2)4 solution and reacted at 120°C for 8 h. (4) After the reactor cools down, remove the solution and dry it at 70°C for 30 min to obtain the MoS2-PDA-NiPc(NH2)4-AB composite material of this embodiment.

[0038] When the concentration of NiPc(NH2)4 in the NiPc(NH2)4 solution is 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL and 0.5 mg / mL, the prepared MoS2-PDA-NiPc(NH2)4-AB composite materials are respectively named MoS2-PDA-NiPc(NH2)40.2-AB, MoS2-PDA-NiPc(NH2)40.3-AB, MoS2-PDA-NiPc(NH2)40.4-AB and MoS2-PDA-NiPc(NH2)40.5-AB.

[0039] The FTO substrate with MoS2 nanosheet arrays attached to its surface was prepared by a method including the following steps: A1. Take 0.3g of Dissolve 0.8 g of thiourea in 50 mL of deionized water, stir magnetically for 45 min and sonicate for 10 min to obtain a homogeneous precursor solution; A2. Place one pre-cleaned FTO substrate (2cm long, 1cm wide, and 2mm thick) and 7mL of the precursor solution obtained in step A1 into a polytetrafluoroethylene-lined reactor. Control the solution filling degree to below 80%. Perform a hydrothermal reaction at 190℃ for 15h. After the reaction is completed, allow it to cool naturally, remove the FTO, rinse it repeatedly with deionized water and ethanol, and dry it at 70℃ to obtain an FTO substrate with a MoS2 nanosheet array on the surface.

[0040] NiPc(NH2)4 was prepared by a method including the following steps: B1. Under nitrogen protection, 1.2 g of nitrophthalonitrile and 0.42 g of nickel acetate tetrahydrate were added to a three-necked flask at a molar ratio of 4.5:1. 30 mL of DMF was added, and the system was heated to 170 °C and refluxed for 10 h under continuous stirring. After the reaction was completed, the mixture was cooled to room temperature, and the solid product was collected by filtration. The solid product was washed repeatedly with ethanol, deionized water and acetone to remove unreacted raw materials and low molecular weight impurities to obtain tetranitronickel phthalocyanine intermediate. B2. Disperse the obtained 1.2g tetranitronickel phthalocyanine intermediate in 30mL DMF, and add excess (12g) under nitrogen protection. Add 1 mL of 37 wt% hydrochloric acid solution to provide an acidic environment, and stir the reaction at 75 °C for 5 h to gradually reduce the nitro group to amino. B3. After the reaction is complete, the system is poured into a large amount of deionized water. The resulting dark precipitate is collected by vacuum filtration and repeatedly washed with water and ethanol to remove tin salt and acid residue. Finally, it is washed with solvent to obtain tetraaminonickel phthalocyanine (NiPc(NH2)4).

[0041] Example 2 The MoS2-PDA-NiPc(NH2)4-AB composite material of this embodiment was prepared by a method including the following steps: (1) In an aqueous solution containing dopamine hydrochloride (concentration of 0.5 mg / mL) and acetylene black, NaOH was used as a pH adjuster to adjust the pH to 8.5 to obtain a mixed solution; (2) The FTO substrate with MoS2 nanosheet array attached to its surface was immersed in 60 mL of the above solution for 0.5 h, and then dried at 60 °C for 30 min to obtain the MoS2-PDA-AB composite material. (3) Using DMA as a solvent, NiPc(NH2)4 was dissolved in a water bath at 60°C to obtain a NiPc(NH2)4 solution (the concentration of NiPc(NH2)4 was 0.2 mg / mL). The FTO substrate with MoS2-PDA-AB composite material deposited on its surface was placed in 7 mL of NiPc(NH2)4 solution and reacted at 120°C for 6 h. (4) After the reactor cools down, remove the solution and dry it at 70°C for 30 min to obtain the MoS2-PDA-NiPc(NH2)4-AB composite material of this embodiment.

[0042] When the concentration of acetylene black in the mixed solution of step (1) is 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL and 0.5 mg / mL, the prepared MoS2-PDA-NiPc(NH2)4-AB composite materials are respectively named MoS2-PDA-NiPc(NH2)4-0.1AB, MoS2-PDA-NiPc(NH2)4-0.2AB, MoS2-PDA-NiPc(NH2)4-0.3AB, MoS2-PDA-NiPc(NH2)4-0.4AB and MoS2-PDA-NiPc(NH2)4-0.5AB.

[0043] The FTO substrate with a MoS2 nanosheet array on its surface was prepared by a method including the following steps: A1. Take 0.2g of Dissolve 0.53 g of thiourea in 40 mL of deionized water, stir magnetically for 30 min and sonicate for 10 min to obtain a homogeneous precursor solution; A2. Place the pre-cleaned FTO substrate and the precursor solution obtained in step A1 into a polytetrafluoroethylene-lined reactor. Control the solution filling degree to below 80%. Perform a hydrothermal reaction at 180°C for 12 hours. After the reaction is completed, allow it to cool naturally. Remove the FTO, rinse it repeatedly with deionized water and ethanol, and dry it at 60°C to obtain an FTO substrate with a MoS2 nanosheet array on the surface.

[0044] NiPc(NH2)4 was prepared by a method including the following steps: B1. Under nitrogen protection, 1 g of nitrophthalonitrile and 0.33 g of nickel acetate tetrahydrate were added to a three-necked flask in a molar ratio, and 20 mL of DMF was added. The system was heated to 160 °C and refluxed for 8 h under continuous stirring. After the reaction was completed, the mixture was cooled to room temperature, and the solid product was collected by filtration. The solid product was washed repeatedly with ethanol, deionized water and acetone to remove unreacted raw materials and low molecular weight impurities to obtain tetranitronickel phthalocyanine intermediate. B2. Disperse the obtained 0.96g tetranitronickel phthalocyanine intermediate in 30mL DMF, and add 4.8g under nitrogen protection. Add 1 mL of 37 wt% hydrochloric acid to provide an acidic environment, and stir the reaction at 70 °C for 4 h to gradually reduce the nitro group to amino. B3. After the reaction is complete, the system is poured into a large amount of deionized water. The resulting dark precipitate is collected by vacuum filtration and repeatedly washed with water and ethanol to remove tin salt and acid residue. Finally, it is washed with solvent to obtain tetraaminonickel phthalocyanine (NiPc(NH2)4).

[0045] Example 3 The MoS2-PDA-NiPc(NH2)4-AB composite material of this embodiment was prepared by a method including the following steps: (1) In an aqueous solution containing dopamine hydrochloride (concentration of 0.3 mg / mL) and acetylene black (concentration of 0.5 mg / mL), NaOH was used as a pH adjuster to make the pH 8.5 to obtain a mixed solution; (2) The FTO substrate with MoS2 nanosheet array attached to its surface was immersed in 60 mL of the above solution for 3 h, and then dried at 60 °C for 30 min to obtain the MoS2-PDA-AB composite material. (3) Using DMA as a solvent, NiPc(NH2)4 was dissolved in a water bath at 60°C to obtain a NiPc(NH2)4 solution (the concentration of NiPc(NH2)4 was 0.5 mg / mL). The FTO substrate with MoS2-PDA-AB composite material deposited on its surface was placed in the NiPc(NH2)4 solution and subjected to a solvothermal reaction at 120°C for 10 h. (4) After the reactor cools down, remove the solution and dry it at 70°C for 30 min to obtain the MoS2-PDA-NiPc(NH2)4-AB composite material of this embodiment.

[0046] The FTO substrate with MoS2 nanosheet arrays attached to its surface was prepared using a method comprising the following steps: A1. Take 0.4g Dissolve 1.07 g of thiourea in 60 mL of deionized water, stir magnetically for 60 min and sonicate for 10 min to obtain a homogeneous precursor solution; A2. Place one pre-cleaned FTO substrate and 7 mL of the precursor solution obtained in step A1 into a polytetrafluoroethylene-lined reactor. Control the solution filling degree to be below 80%. Perform hydrothermal reaction at 200℃ for 18 hours. After the reaction is completed, allow it to cool naturally. Remove the FTO, rinse it repeatedly with deionized water and ethanol, and dry it at 80℃ to obtain an FTO substrate with a MoS2 nanosheet array on the surface.

[0047] NiPc(NH2)4 was prepared by a method including the following steps: B1. Under nitrogen protection, 1.4 g of nitrophthalonitrile and 0.52 g of nickel acetate tetrahydrate were added to a three-necked flask in a molar ratio, and 50 mL of DMF was added. The system was heated to 180 °C and refluxed for 12 h under continuous stirring. After the reaction was completed, the mixture was cooled to room temperature, and the solid product was collected by filtration. The solid product was washed repeatedly with ethanol, deionized water and acetone to remove unreacted raw materials and low molecular weight impurities to obtain tetranitronickel phthalocyanine intermediate. B2. Disperse the obtained 1.5g tetranitronickel phthalocyanine intermediate in 30mL DMF, and add 22.5g under nitrogen protection. A small amount of hydrochloric acid was added dropwise to provide an acidic environment, and the reaction was stirred at 80°C for 6 hours to gradually reduce the nitro groups to amino groups. B3. After the reaction is complete, the system is poured into a large amount of deionized water. The resulting dark precipitate is collected by vacuum filtration and repeatedly washed with water and ethanol to remove tin salt and acid residue. Finally, it is washed with solvent to obtain tetraaminonickel phthalocyanine (NiPc(NH2)4).

[0048] Example 4 The only difference between this comparative example and Example 1 is that the temperature of the solvothermal reaction in step (3) is different; the rest are the same as in Experiment 1.

[0049] The solvothermal temperatures were set to 80℃, 100℃, 120℃, and 140℃, respectively. The MoS2-PDA-NiPc(NH2)4-AB composite materials prepared at different solvothermal temperatures were respectively named MoS2-PDA-NiPc(NH2)4-80℃-AB, MoS2-PDA-NiPc(NH2)4-100℃-AB, MoS2-PDA-NiPc(NH2)4-120℃-AB, and MoS2-PDA-NiPc(NH2)4-140℃-AB.

[0050] Comparative Example 1 The only difference between this comparative example and the MoS2-PDA-NiPc(NH2)40.3-AB in Example 1 is that the composite material in this comparative example is an FTO substrate with a MoS2 nanosheet array on the surface (prepared according to the same method as in Example 1); all other aspects are consistent with Example 1.

[0051] The composite material in this comparative example is denoted as MoS2.

[0052] Comparative Example 2 The only difference between this comparative example and the MoS2-PDA-NiPc(NH2)40.3-AB in Example 1 is that steps (3)-(4) and the step of adding acetylene black in step (1) are omitted. All other steps are the same as in Example 1.

[0053] Specifically, the composite material of this comparative example was prepared by a method including the following steps: (1) In an aqueous solution of dopamine hydrochloride with a concentration of 1 mg / mL, NaOH was used as a pH adjuster to make the pH 8.5, and a mixed solution was obtained; (2) One FTO substrate with MoS2 nanosheet array on the surface (preparation method is the same as in Example 1) was immersed in 60 mL of the above mixed solution for 1 h, and then dried at 60 °C for 30 min to obtain MoS2-PDA composite material.

[0054] Comparative Example 3 The only difference between this comparative example and the MoS2-PDA-NiPc(NH2)40.3-AB in Example 1 is that the mixed solution in step (1) does not contain acetylene black, while the rest is consistent with Example 1.

[0055] The composite material in this comparative example is denoted as MoS2-PDA-NiPc(NH2)4 composite material.

[0056] Comparative Example 4 The only difference between this comparative example and the MoS2-PDA-NiPc(NH2)40.3-AB in Example 1 is that steps (3)-(4) are omitted, while the rest are the same as in Example 1.

[0057] Specifically, the composite material of this comparative example was prepared by a method including the following steps: (1) In an aqueous solution of dopamine hydrochloride with a mass-to-volume ratio of 1 mg / mL and 0.3 mg / mL acetylene black, NaOH was used as a pH adjuster to make the pH 8.5 to obtain a mixed solution; (2) An FTO substrate with an array of MoS2 nanosheets on its surface (the FTO substrate has a length of 2 cm, a width of 1 cm, and a thickness of 2 mm; the preparation method is the same as in Example 1) was immersed in 60 mL of the above mixed solution for 1 h, and then dried at 60 °C for 30 min to obtain the MoS2-PDA-AB composite material. The composite material in this comparative example is denoted as MoS2-PDA-AB.

[0058] Experimental Example 1. Electrochemical performance testing: (1) Measure the OCP and it curves of different composite materials coupled with 304SS: Test Method: The photocathode protection test device consists of two electrolytic cells: a corrosion cell and a photocell, connected by a salt bridge. The electrolyte in the corrosion cell is a 3.5 wt% NaCl solution, while the electrolyte in the photocell is a 0.1 mol / L Na₂S and a 0.2 mol / L NaOH solution. The protected metal, 304 stainless steel, is placed in the corrosion cell as the working electrode, silver chloride as the reference electrode, and a platinum sheet as the counter electrode. The prepared FTO conductive glass of the coated sample is placed in the photocell, and the 304 stainless steel and FTO conductive glass are connected by wires. A 300W xenon lamp is used as the light source. The changes in photocurrent-time curves and open-circuit potential-time curves under illumination are measured using a CHI 660E electrochemical workstation.

[0059] The test results of Example 1 and Comparative Examples 1-4 are as follows: Figure 1 As shown; OCP test results show that the system exhibits varying degrees of mixing potential decrease under visible light irradiation. This potential shift originates from the photogenerated potential difference formed between the illuminated and dark states after the composite material is coupled with 304 stainless steel. Generally, the greater the negative shift of the OCP potential relative to the dark state under illumination, the stronger the photoanode can provide photogenerated electron driving force to the MoS2 matrix, thus exhibiting higher photocathode protection capability; related test results show ( Figure 1(a) The photoexcitation potential drops of the MoS2 composite material of Comparative Example 1, the MoS2-PDA composite material of Comparative Example 2, the MoS2-PDA-NiPc(NH2)4 composite material of Comparative Example 3, the MoS2-PDA-AB composite material of Comparative Example 4, and the MoS2-PDA-NiPc(NH2)4-AB composite material of Example 1 (MoS2-PDA-NiPc(NH2)40.3-AB) reached -0.90V, -0.95V, -0.98V, -0.94V, and -1.05V respectively, all significantly lower than the self-corrosion potential of 304SS. It is worth noting that the photoinduced displacement amplitude of the composites of MoS2, PDA, AB and NiPc(NH2)4 is generally better than that of MoS2 alone, and gradually increases with the change of materials, with the sample of MoS2-PDA-NiPc(NH2)4-AB composite material showing the most outstanding performance.

[0060] The current-time (it) curve can be used to further evaluate the separation and migration behavior of photogenerated carriers under illumination. The larger the transient current, the higher the photocurrent density, and the more photogenerated electrons the photoanode can provide to the 304SS. Figure 1 (b) The experimental results show that both the MoS2-PDA-NiPc(NH2)4-AB composite material of Example 1 and 304SS generate positive photocurrents under intermittent illumination, indicating the effective transfer of photogenerated electrons to 304SS. The photocurrent densities of MoS2 in Comparative Example 1, MoS2-PDA composite material in Comparative Example 2, MoS2-PDA-NiPc(NH2)4 composite material in Comparative Example 3, MoS2-PDA-AB composite material in Comparative Example 4, and MoS2-PDA-NiPc(NH2)4-AB composite material in Example 1 are 220 μA / cm², respectively. 2 380μA / cm 2 410μA / cm 2 270μA / cm 2 600μA / cm 2 Among them, the MoS2-PDA-NiPc(NH2)4-AB composite material in Example 1 exhibited the highest photocurrent density, indicating that it has a higher photogenerated carrier separation efficiency. Furthermore, the photocurrent recovered to its initial level after multiple light irradiation cycles, demonstrating the system's good photoelectric stability.

[0061] (2) The OCP and it curves of the MoS2-PDA-NiPc(NH2)4-AB composite materials prepared by NiPc(NH2)4 solutions of different concentrations in Example 1 were tested: Test results are as follows Figure 2 As shown; Under visible light, the mixing potential of the system decreases to varying degrees, originating from the potential difference between the illuminated and dark states after the photoelectric material is connected to 304SS. The greater the potential shift, the stronger the photocathode protection capability of the constructed system.

[0062] The OCP test results show that ( Figure 2 (a) The photoexcitation potential drops of MoS2-PDA-NiPc(NH2)40.2-AB, MoS2-PDA-NiPc(NH2)40.3-AB, MoS2-PDA-NiPc(NH2)40.4-AB and MoS2-PDA-NiPc(NH2)40.5-AB reached -0.97V, -1.02V, -0.94V and -0.92V respectively, which were all significantly lower than the self-corrosion potential of 304SS. It is noteworthy that the photoinduced shift amplitude of the composite of MoS2, PDA, and NiPc(NH2)4 is generally better than that of MoS2 alone, and shows a trend of first enhancing and then decreasing with increasing NiPc(NH2)4 concentration, with the sample obtained at a concentration of 0.30 mg / mL showing the most outstanding performance. This is attributed to the fact that under low concentration conditions, the molecular layer formed by NiPc(NH2)4 on the MoS2-PDA-AB surface is usually more dispersed and uniform, which is conducive to constructing a sensitized structure with good interface energy level matching. The low coverage of NiPc(NH2)4 does not significantly block the interaction between MoS2, PDA, and AB and light, so that the light absorption of each component in the quaternary system maintains a synergistic enhancement relationship. An appropriate amount of NiPc(NH2)4 reduces interfacial electronic recombination and maintains a low charge transport impedance, allowing photogenerated carriers to migrate rapidly to MoS2, thereby forming a higher photogenerated negative shift potential. The relatively low protective performance of MoS2-PDA-NiPc(NH2)40.4-AB and MoS2-PDA-NiPc(NH2)40.5-AB may be due to the excessive stacking structure formed by high concentration of NiPc(NH2)4 on the surface of MoS2-PDA-AB, which enhances the π–π stacking between phthalocyanine molecules, thereby introducing a large number of carrier recombination centers and weakening the effective generation of photogenerated electrons. Moreover, as the thickness of the NiPc(NH2)4-AB layer increases, the injection path of electrons from NiPc(NH2)4 to MoS2 is significantly lengthened, and the resistance to interfacial electron migration increases.

[0063] Current-time (i–t) curves can be used to further evaluate the separation and migration behavior of photogenerated carriers under illumination. A larger transient current indicates a higher photocurrent density, and more photogenerated electrons that the photoanode can provide to the 304SS. Figure 2The test results in (b) show that both the MoS2-PDA-NiPc-AB composite material and 304SS generate positive photocurrents under intermittent illumination, indicating the effective transfer of photogenerated electrons to 304SS. The photocurrent densities of MoS2-PDA-NiPc(NH2)40.2-AB, MoS2-PDA-NiPc(NH2)40.3-AB, MoS2-PDA-NiPc(NH2)40.4-AB, and MoS2-PDA-NiPc(NH2)40.5-AB are 490 μA / cm², respectively. 2 586μA / cm 2 422μA / cm 2 245μA / cm 2 Among them, MoS2-PDA-NiPc(NH2)40.3-AB had the highest photocurrent density, indicating that it has a higher photogenerated carrier separation efficiency. In addition, the photocurrent can still recover to the initial level after multiple light cycles, indicating that the system has good photoelectric stability.

[0064] (3) The it curves of the MoS2-PDA-NiPc(NH2)4-AB composite material prepared by mixed solutions with different acetylene black concentrations in Example 2 were tested: Test results are as follows Figure 5 As shown; Depend on Figure 5 It can be seen that the photocurrent densities of MoS2-PDA-NiPc(NH2)4-0.1AB, MoS2-PDA-NiPc(NH2)4-0.2AB, MoS2-PDA-NiPc(NH2)4-0.3AB, MoS2-PDA-NiPc(NH2)4-0.4AB, and MoS2-PDA-NiPc(NH2)4-0.5AB are 245 μA / cm², respectively. 2 320μA / cm 2 480μA / cm 2 205μA / cm 2 170μA / cm 2 .

[0065] (4) The OCP of the MoS2-PDA-NiPc(NH2)4-AB composite material prepared in Example 4 at different solvothermal reaction temperatures was tested: Test results are as follows Figure 6 As shown; Depend on Figure 6It can be seen that the photoexcitation potential drops of MoS2-PDA-NiPc(NH2)4-80℃-AB, MoS2-PDA-NiPc(NH2)4-100℃-AB, MoS2-PDA-NiPc(NH2)4-120℃-AB and MoS2-PDA-NiPc(NH2)4-140℃-AB are -0.94V, -0.97V, -1.05V and -0.93V respectively.

[0066] 2. Electrochemical Impedance Spectroscopy (EIS) Test: To further analyze the interfacial charge transport characteristics of materials under illumination, electrochemical impedance spectroscopy (EIS) was performed on different electrode materials. A three-electrode system was used. The photoanode served as the working electrode, immersed in the electrolyte. A platinum sheet served as the counter electrode, placed on the other side of the electrolyte. A saturated calomel electrode served as the reference electrode (RE), placed near the photoanode. The electrolyte solution was 0.1 mol / L Na₂SO₄. Each electrode was connected to an electrochemical workstation via wires. Impedance spectra were recorded using the electrochemical workstation, and the obtained data were fitted and analyzed using ZView software. Electrochemical impedance spectroscopy reflects the charge transfer resistance at the electrode / electrolyte interface; the size of the semicircle in the high-frequency region of the Nyquist curve corresponds to the charge transfer resistance.

[0067] Figure 3 Electrochemical impedance spectroscopy (EIS) spectra of the MoS2-PDA-NiPc(NH2)4-AB composite material (MoS2-PDA-NiPc(NH2)40.3-AB) of Example 1, the MoS2 composite material of Comparative Example 1, the MoS2-PDA composite material of Comparative Example 2, the MoS2-PDA-NiPc(NH2)4 composite material of Comparative Example 3, and the MoS2-PDA-AB composite material of Comparative Example 4 in typical electrolytes are presented. All samples exhibit a semi-circular characteristic in the high-frequency region, with the semi-circular diameter corresponding to the interfacial charge transfer resistance. As the materials are progressively composited, the Nyquist semi-circular diameter decreases significantly, with the MoS2-PDA-NiPc(NH2)4-AB composite material (Example 1) exhibiting the smallest semi-circular radius, indicating the lowest charge transfer resistance. This demonstrates that the synergistic effect of the multiple components, especially the introduction of acetylene black, is beneficial in promoting interfacial charge transport.

[0068] 3. Ultraviolet-Visible Diffuse Reflectance Spectroscopy Test: Ultraviolet-visible diffuse reflectance (UV-Vis DRS) spectroscopy measurements were performed on a spectrophotometer with an integrating sphere, covering a wavelength range of 200-1000 nm. A combination of deuterium and tungsten lamps was used as the light source. The powder sample was ground uniformly and directly filled into the sample chamber, with BaSO4 used as a 100% reflectance reference for calibration. The diffuse reflectance spectrum was then obtained.

[0069] The test results of the MoS2-PDA-NiPc(NH2)4-AB composite material (MoS2-PDA-NiPc(NH2)40.3-AB) of Example 1, the MoS2 composite material of Comparative Example 1, the MoS2-PDA composite material of Comparative Example 2, the MoS2-PDA-NiPc(NH2)4 composite material of Comparative Example 3, and the MoS2-PDA-AB composite material of Comparative Example 4 are as follows: Figure 4 As shown; Depend on Figure 4 It can be seen that: MoS2 in Comparative Example 1 exhibits certain light absorption capabilities in the ultraviolet and visible light regions; the MoS2-PDA composite material in Comparative Example 2, after being modified with PDA on the basis of MoS2, shows a significant enhancement in absorption intensity across the entire wavelength range, mainly attributed to the excellent broadband absorption characteristics of PDA; based on this, the introduction of NiPc(NH2)4 in Comparative Example 3 further enhances the absorption of the MoS2-PDA-NiPc(NH2)4 composite material in the visible and near-infrared regions, indicating that the introduction of phthalocyanine molecules effectively expands the photoresponse range of the material; after adding acetylene black (AB), the MoS2-PDA-NiPc(NH2)4-AB composite material (MoS2-PDA-NiPc(NH2)40.3-AB) in Example 1 exhibits the strongest light absorption capability across the entire test wavelength range, especially with a significant enhancement in absorption in the visible and near-infrared regions. This is mainly attributed to the excellent light absorption capability and conductivity of acetylene black, which is beneficial for the rapid transport and separation of photogenerated carriers.

[0070] Figure 4 The UV-Vis absorption spectra showed that pure MoS2 had weak absorption in the visible region. After introducing PDA (MoS2-PDA in Comparative Example 2), the absorption intensity of the material in both the UV and visible regions was significantly improved, indicating that PDA successfully modified and enhanced the light-harvesting ability of the system. Based on this, after compounding with AB (MoS2-PDA-AB in Comparative Example 4), the overall absorption of the system in the 200-1000 nm range was further improved, but no new characteristic absorption peaks appeared, indicating that acetylene black mainly enhances background absorption and light utilization efficiency through its broad-spectrum absorption characteristics. Further introduction of NiPc(NH2)4 (MoS2-PDA-NiPc(NH2)4-AB in Example 1) showed a significant enhancement in absorption in the 600-700 nm region, corresponding to the characteristic Q-band absorption of phthalocyanine compounds, indicating that it was successfully loaded into the composite system. The resulting MoS2-PDA-NiPc(NH2)4-AB composite material exhibits the strongest absorption intensity and a wider light response range across the entire wavelength range, demonstrating the synergistic effect between the components, which is beneficial to improving the material's light absorption capacity and photoelectric conversion efficiency.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a MoS2-PDA-NiPc(NH2)4-AB composite material, characterized in that, Includes the following steps: (1) The substrate with MoS2 nanosheet arrays attached to its surface is immersed in a mixed solution containing dopamine hydrochloride and acetylene black. After immersion, it is dried to obtain MoS2-PDA-AB composite material. (2) The MoS2-PDA-AB composite material was placed in a tetraaminonickel phthalocyanine solution and subjected to a solvothermal reaction; (3) After the solvothermal reaction is completed, the solid and liquid are separated, and the obtained solid is dried to obtain the MoS2-PDA-NiPc(NH2)4-AB composite material.

2. The preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material as described in claim 1, characterized in that, In step (1), the concentration of dopamine hydrochloride in the mixed solution is 0.5-3 mg / mL, and the concentration of acetylene black is 0.1-0.5 mg / mL; the pH of the mixed solution is 8-9. In step (1), the soaking time is 0.5-3 hours.

3. The preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material as described in claim 1, characterized in that, In step (2), the temperature of the solvothermal reaction is 80-140℃, and the reaction time is 6-12h; In step (2), the concentration of the tetraaminonickel phthalocyanine solution is 0.2-0.5 mg / mL.

4. The preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material as described in claim 1, characterized in that, In step (1), the substrate with the MoS2 nanosheet array attached to its surface is prepared by a method including the following steps: A1, will Thiourea was dissolved in deionized water and mixed thoroughly to obtain a homogeneous precursor solution; A2. Place the substrate and the precursor liquid into a polytetrafluoroethylene-lined reactor and perform a hydrothermal reaction at 180-200°C for 12-18 hours. A3. After the reaction is complete, allow the mixture to cool naturally, remove the reaction solution, clean and dry to obtain a substrate with a MoS2 nanosheet array attached to its surface.

5. The preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material as described in claim 4, characterized in that, In step A1, The molar ratio of thiourea to thiourea is 1:5-1:12; the method of mixing is to magnetically stir for 30-60 minutes and then sonicate for 5-20 minutes. In step A3, deionized water and ethanol are used for cleaning; the drying temperature is 60-80℃.

6. The preparation method of the MoS2-PDA-NiPc(NH2)4-AB composite material as described in claim 1, characterized in that, The tetraaminonipotassium phthalocyanine solution was prepared by a method comprising the following steps: B1. Under nitrogen protection, nitrophthalonitrile and nickel acetate tetrahydrate were added to a reaction vessel in a molar ratio, DMF was added, and the mixture was heated to 160-180℃ and refluxed for 8-12 hours with continuous stirring. After the reaction was completed, the mixture was cooled to room temperature, filtered to collect the solid product, washed, and the tetranitronickel phthalocyanine intermediate was obtained. B2. Disperse the tetranitronickel phthalocyanine intermediate in DMF, and add it under nitrogen protection. Adjust the pH to 1-2 and stir the reaction at 70-80℃ for 4-6 hours; B3. After the reaction is complete, pour the reaction solution into deionized water, collect the precipitate, and wash the precipitate to obtain tetraaminonickel phthalocyanine.

7. The method for preparing the MoS2-PDA-NiPc(NH2)4-AB composite material as described in claim 6, characterized in that, In step B1, the molar ratio of nitrophthalonitrile to nickel acetate tetrahydrate is 4:1-5:1; in step B1, the washing is performed sequentially with ethanol, deionized water and acetone. In step B2, the tetranitronickel phthalocyanine intermediate and The mass ratio is 1:5-1:15; in step B2, hydrochloric acid is used to adjust the pH. In step B3, the product is washed with water and ethanol, followed by washing with an organic solvent.

8. A MoS2-PDA-NiPc(NH2)4-AB composite material, characterized in that, The MoS2-PDA-NiPc(NH2)4-AB composite material was prepared by the method described in any one of claims 1-7.

9. The application of the MoS2-PDA-NiPc(NH2)4-AB composite material as described in claim 8 in photocathode protection.

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