Covalent organic polymer material modified by gold nanoparticles as well as preparation method and application of covalent organic polymer material

Abstract

The invention discloses a covalent organic polymer material modified by gold nanoparticles, and belongs to the technical field of covalent organic polymer materials. The invention discloses a covalent organic polymer material modified by gold nanoparticles. The covalent organic polymer material comprises a covalent organic polymer and the gold nanoparticles loaded on the surface of the covalent organic polymer, the covalent organic polymer material is formed by fully reacting an aldehyde group in 5, 5 ', 5' '-(benzene-1, 3, 5-triyl) tri (thiophene-2-formaldehyde) with an amino group and a sulfydryl group in 2, 5-diamino-1, 4-benzene dithiol dihydrochloride and forming a bond, and is a covalent organic polymer rich in benzothiazole, thiophene and benzene units. The material can synergistically utilize the built-in electric field effect of a Schottky junction and the localized surface plasmon resonance (LSPR) effect of Au, the light response current intensity can be effectively improved, the separation of electron-hole pairs is effectively promoted, and the hydrophilicity and the specific surface area of the covalent organic polymer material are improved.

Description

Technical Field

[0001] This invention relates to the field of covalent organic polymer materials technology, and more specifically, to a gold nanoparticle-modified covalent organic polymer material, its preparation method, and its application. Background Technology

[0002] Solar-powered seawater batteries use seawater as an electrolyte and rely on oxygen in the air to continuously oxidize the positive electrode metal to generate current. The oxygen evolution reaction (OER) is achieved through a photocatalytic photoelectrode.

[0003] Developing efficient and stable optoelectronic functional materials is key to advancing the field of solar-powered seawater batteries. Ideal photoelectrode materials should possess broad-spectrum light absorption, efficient carrier separation and transport capabilities, and good chemical stability. Among numerous candidate materials, covalent organic polymers (COPs) exhibit great potential due to their tunable band structure, highly ordered pores, and abundant π-conjugated systems, and are considered a next-generation organic semiconductor material.

[0004] However, COP materials still face significant challenges in practical applications. First, their photogenerated electron-hole pairs readily recombine rapidly, resulting in low quantum efficiency. Second, many COP materials have limited absorption ranges for visible light, failing to fully utilize the solar spectrum. Furthermore, their electrical conductivity is typically low, limiting the migration rate of photogenerated charges and leading to excessively low photoresponse current intensity. These factors collectively restrict further improvements in the photoelectric properties of COP materials.

[0005] A two-dimensional covalent organic framework material with carbon-carbon double bonds was synthesized via aldol polycondensation using existing technology. This material exhibited a strength of 18 µA / cm² under irradiation at 0.3 V vs. RHE and AM 1.5 G. 2 It has a stable photocurrent. However, its photoresponse current intensity is still too low.

[0006] Therefore, existing technologies still lack a solution that can simultaneously and synergistically address the insufficient light absorption capacity, low photoresponse current intensity, and low carrier separation efficiency of COP materials. Summary of the Invention

[0007] The technical problem this invention aims to solve is to address the shortcomings and deficiencies of existing technologies by providing a covalent organic polymer material modified with gold nanoparticles. This covalent organic polymer material possesses excellent light absorption capabilities. By introducing gold nanoparticles, the built-in electric field effect of the Schottky junction and the localized surface plasmon resonance (LSPR) effect of Au are synergistically utilized to effectively improve the photoresponse current intensity. Simultaneously, its built-in electric field provides a directional driving force for photogenerated carriers, effectively promoting the separation of electron-hole pairs.

[0008] Another object of the present invention is to provide a photoelectrode.

[0009] Another object of the present invention is to provide a solar-powered seawater battery.

[0010] The above-mentioned objective of this invention is achieved through the following technical solution: A covalent organic polymer material modified with gold nanoparticles, comprising a covalent organic polymer and gold nanoparticles loaded on the surface of the covalent organic polymer; The covalent organic polymer has repeating units with the following structure:

[0011] The average particle size of the gold nanoparticles is 2.3–8.9 nm; The mass of the gold nanoparticles is 0.3 to 0.7% of the total mass of the covalent organic polymer material modified with the gold nanoparticles.

[0012] This invention provides a gold nanoparticle-modified covalent organic polymer material. This covalent organic polymer material is formed by the full reaction and bonding of the aldehyde group in 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) (TTB) with the amino and thiol groups in 2,5-diamino-1,4-benzenedithiol dihydrochloride (DABDT). It is a covalent organic polymer rich in benzothiazole, thiophene, and benzene units. The covalent organic polymer material exhibits excellent light absorption capabilities. Gold nanoparticles are deposited on the surface of the covalent organic polymer. This gold nanoparticle-modified covalent organic polymer material can synergistically utilize the built-in electric field effect of the Schottky junction and the localized surface plasmon resonance (LSPR) effect of Au, effectively improving the photoresponse current intensity. Simultaneously, its built-in electric field provides a directional driving force for photogenerated carriers, effectively promoting the separation of electron-hole pairs. Furthermore, the introduction of gold nanoparticles can enhance the hydrophilicity of covalent organic polymer materials, which is beneficial for the adsorption and activation of oxygen molecules. Therefore, this gold nanoparticle-modified covalent organic polymer material can serve as a catalyst to improve the catalytic activity of the oxygen evolution reaction (OER) three-phase interface reaction. The introduction of gold nanoparticles can also increase the specific surface area of ​​the covalent organic polymer material, providing more active sites.

[0013] Preferably, the covalent organic polymer is obtained by polymerization of two monomers, 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride.

[0014] Preferably, the preparation method of the gold nanoparticle-modified covalent organic polymer material includes the following steps: S1. The covalent organic polymer is obtained by polymerizing 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride. S2. Irradiate the mixed solution of covalent organic polymer, chloroauric acid and triethanolamine obtained in step S1 with a xenon lamp to obtain a covalent organic polymer material modified with gold nanoparticles.

[0015] In a specific embodiment, the preparation method of the gold nanoparticle-modified covalent organic polymer material includes the following steps: S1. Dissolve 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride in mixed organic solvent A, pour into a reaction vessel, and start the polymerization reaction. After the reaction is completed, filter under vacuum and wash with solvent B to obtain the solid product covalent organic polymer. S2. The covalent organic polymer obtained in step S1 is dispersed in deionized water, chloroauric acid and triethanolamine are added and stirred evenly, and the mixed solution is irradiated with a xenon lamp to obtain an organic polymer material modified with gold nanoparticles.

[0016] In a specific embodiment, in step S1, the mixed organic solvent A includes A1, A2 and A3, wherein A1 is N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, A2 is methanol, ethanol or n-butanol, and A3 is acetic acid, and the volume ratio of A1:A2:A3 is (8~10):(0.9~1.1):(0.01~0.03).

[0017] In a specific implementation, in step S1, solvent B can be methanol.

[0018] In a specific implementation, in step S2, after stirring evenly, argon gas can be introduced into the solution to remove oxygen.

[0019] The present invention also protects a photoelectrode comprising a substrate and a catalyst supported on the substrate, wherein the catalyst is a covalent organic polymer material modified with gold nanoparticles as described above.

[0020] Preferably, the substrate is hydrophilic carbon paper.

[0021] This invention also protects the method for preparing the above-mentioned photoelectrode, comprising the following steps: S1. 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride were polymerized on a substrate to obtain a covalent organic polymer-coated substrate composite material. S2. The photoelectrode is obtained by irradiating the mixed solution of the covalent organic polymer-coated substrate composite material, chloroauric acid, and triethanolamine obtained in step S1 with a xenon lamp; In step S1, the molar ratio of 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride is 1:(1~2); the polymerization temperature is 140~200℃, and the polymerization time is 8~32h; In step S2, the power of the xenon lamp is 240~360W, and the irradiation time is 30~90min.

[0022] In step S1 of this invention, a covalent organic polymer rich in benzothiazole, thiophene, and benzene units is prepared by mixing 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride on a substrate. This covalent organic polymer material exhibits excellent light absorption capabilities. In step S2 of this invention, gold nanoparticles are deposited on the covalent organic polymer using a photoreduction method to obtain a Schottky heterojunction photoelectrode. The introduction of gold nanoparticles can improve the hydrophilicity and specific surface area of ​​the photoelectrode. The enhanced hydrophilicity is beneficial for electrolyte wetting and oxygen adsorption and activation. Therefore, this covalent organic polymer material modified with gold nanoparticles can serve as a catalyst for the photoelectrode, improving the catalytic activity of the oxygen evolution reaction (OER) three-phase interface reaction. The increased specific surface area provides more active sites. Simultaneously, it can improve electrode surface activity, specific surface area, and hydrophilicity, effectively enhancing the photoelectrochemical catalytic activity of the photoelectrode.

[0023] The method for preparing the photoelectrode of the present invention enables the in-situ loading of a covalent organic polymer modified with gold nanoparticles onto a substrate.

[0024] In step S2 of this invention, triethanolamine is used to reduce gold ions to generate gold nanoparticles.

[0025] In step S2 of this invention, the particle size of gold nanoparticles is controlled by adjusting the power of the xenon lamp and the irradiation time. Lower power and shorter irradiation time are beneficial for forming smaller gold nanoparticles.

[0026] Preferably, in step S1, the molar ratio of TTB to DABDT is 1:(1.4-1.6). When the molar ratio of TTB to DABDT is 1:(1.4-1.6), the aldehyde group in TTB can react and bond more fully with the amino and thiol groups in DABDT to form a more complete covalent organic polymer.

[0027] Preferably, in step S1, the concentration of TTB in the mixed organic solvent is 1.3~1.4 g / L. The concentration of DABDT in the mixed organic solvent is 1.3~1.4 g / L.

[0028] Preferably, in step S2, the mass fraction of chloroauric acid in the mixed solution is 0.015~0.025 wt%. The mass fraction of triethanolamine in the mixed solution is 10~14 wt%.

[0029] Preferably, in step S1, the polymerization reaction temperature is 160~180℃ and the polymerization reaction time is 20~28h.

[0030] At a reaction temperature of 160-180℃ and a reaction time of 20-28h, TTB and DABDT can react more fully.

[0031] Preferably, in step S2, the power of the xenon lamp is 280~320W, and the irradiation time is 50~70min.

[0032] When the reactive xenon lamp power is 280~320W and the irradiation time is 50~70min, gold nanoparticles can be deposited better on covalent organic polymers.

[0033] In a specific embodiment, the method for preparing the photoelectrode includes the following steps: S1. Dissolve 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride in mixed organic solvent A, pour the solution into a polytetrafluoroethylene reactor, place several pieces of carbon paper at a certain angle in the polytetrafluoroethylene reactor, start the polymerization reaction, after the reaction is completed, vacuum filter and wash with solvent B to obtain a covalent organic polymer-coated substrate composite material; S2. Disperse chloroauric acid in deionized water, add triethanolamine, add the covalent organic polymer-coated substrate composite material obtained in step S1, and irradiate with a xenon lamp to obtain a photoelectrode.

[0034] Preferably, in step S1, the mixed organic solvent A includes A1, A2 and A3, wherein A1 is N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, A2 is methanol, ethanol or n-butanol, A3 is acetic acid, and the volume ratio of A1:A2:A3 is (8~10):(0.9~1.1):(0.01~0.03).

[0035] In a specific implementation, in step S1, solvent B can be methanol.

[0036] In a specific implementation, in step S2, after stirring evenly, argon gas can be introduced into the solution to remove oxygen.

[0037] In a specific implementation, several carbon sheets can be placed in the reaction vessel at a certain angle so that each carbon sheet can be in full contact with the solution.

[0038] This invention also protects a solar-powered seawater battery, comprising a photoelectrode, a metal electrode, and an electrolyte connecting the photoelectrode and the metal electrode, wherein the photoelectrode is the aforementioned photoelectrode. The electrolyte is seawater.

[0039] Preferably, the metal electrode is zinc, sodium, aluminum or magnesium.

[0040] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a gold nanoparticle-modified covalent organic polymer material. The covalent organic polymer material is formed by the reaction and bonding of the aldehyde group in 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) (TTB) with the amino and thiol groups in 2,5-diamino-1,4-benzenedithiol dihydrochloride (DABDT). It is a covalent organic polymer rich in benzothiazole, thiophene, and benzene units. The covalent organic polymer material exhibits excellent light absorption capabilities. Gold nanoparticles are deposited on the surface of the covalent organic polymer. This material can synergistically utilize the built-in electric field effect of the Schottky junction and the localized surface plasmon resonance (LSPR) effect of Au to effectively improve the photoresponse current intensity. Simultaneously, its built-in electric field provides a directional driving force for photogenerated carriers, effectively promoting the separation of electron-hole pairs. Furthermore, the introduction of gold nanoparticles can also improve the hydrophilicity of the covalent organic polymer material, which is beneficial for the adsorption and activation of oxygen molecules. The introduction of gold nanoparticles can also increase the specific surface area of ​​covalent organic polymer materials, providing more active sites. Attached Figure Description

[0041] Figure 1 The images shown are SEM images of the photoelectrode provided in Embodiment 2 and Comparative Example 2 of the present invention, TEM images provided in Embodiment 2, and particle size distribution diagrams of gold.

[0042] Figure 2 The images show the XRD patterns of the photoelectrodes provided in Embodiment 2 and Comparative Example 2 of the present invention.

[0043] Figure 3 The hydrophobic angle diagrams provided for Embodiment 2 and Comparative Example 2 of the present invention are shown.

[0044] Figure 4 The BET diagrams provided in Embodiment 1 and Comparative Example 1 of the present invention are shown.

[0045] Figure 5 The carbon NMR spectrum of the DT-COP prepared according to Comparative Example 1 of this invention.

[0046] Figure 6 Infrared spectra of DT-COP, DABDT, and TTB prepared according to Comparative Example 1 of this invention.

[0047] Figure 7 The above diagram shows the photoelectric performance of the photoelectrodes provided in Embodiment 2 and Comparative Example 2 of the present invention.

[0048] Figure 8 The images show the cycle stability test diagram and SEM image of the photoelectrode after testing of the solar seawater battery prepared by the photoelectrode provided in Example 2 of this invention.

[0049] Figure 9 The image shows the cycle stability test diagram and the XRD pattern of the photoelectrode after testing of the solar seawater battery prepared by the photoelectrode provided in Example 2 of this invention.

[0050] Figure 10 This is a schematic diagram of the preparation process in Example 2 of the present invention.

[0051] Figure 11 This is a schematic diagram of the operation of the photoelectrode provided in Embodiment 2 of the present invention. Detailed Implementation

[0052] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0053] 5,5',5''-(benzene-1,3,5-triyl)tri(thiophene-2-carboxaldehyde), abbreviated as TTB, CAS number 2125450-22-6. 2,5-Diamino-1,4-benzenedithiol dihydrochloride, abbreviated as DABDT, CAS number 75464-52-7.

[0054] Hydrophilic carbon paper, manufactured by Toray Industries, Japan, model number TGP-H-060.

[0055] Example 1 A covalent organic polymer material modified with gold nanoparticles, comprising a covalent organic polymer and gold nanoparticles loaded on the surface of the covalent organic polymer; Covalent organic polymers have repeating units with the following structure:

[0056] The average particle size of the gold nanoparticles is 2.3–8.9 nm; The mass of the gold nanoparticles is 0.5% of the total mass of the covalent organic polymer material modified with gold nanoparticles.

[0057] The preparation method of the above-mentioned gold nanoparticle-modified covalent organic polymer material includes the following steps: S1. Dissolve 120 mg DABDT and 133.2 mg TTB (TTB to DABDT molar ratio of 1:1.5) in 90 mL N-methylpyrrolidone (NMP), 10 mL methanol, and 0.1 mL acetic acid (N-methylpyrrolidone, methanol, and acetic acid volume ratio of 9:1:0.01), and pour the solution into a clean reaction vessel. Then seal the reaction vessel and place it in an oven at 170 °C for 24 hours. After the reaction is complete, wash with methanol and dry to form DT-COP.

[0058] S2. Disperse 100 mg DT-COP in 50 mL of deionized water, and add 10 mg chloroauric acid and 10 mL triethanolamine. After stirring evenly, argon gas is introduced into the solution for 30 minutes, followed by irradiation under a 300 W xenon lamp for 1 hour, and then thoroughly rinsed with deionized water to form a covalent organic polymer composite material modified with Au@DT-COP gold nanoparticles.

[0059] ICP analysis revealed that the mass of the gold nanoparticles in the gold nanoparticle-modified covalent organic polymer material was 0.5% of the total mass of the gold nanoparticle-modified covalent organic polymer material.

[0060] Example 2 A photoelectrode includes a hydrophilic carbon paper substrate and a catalyst supported on the hydrophilic carbon paper substrate. The catalyst is a covalent organic polymer material modified with gold nanoparticles as described in Example 1.

[0061] The above-mentioned method for preparing the photoelectrode includes the following steps: S1. Dissolve 120 mg DABDT and 133.2 mg TTB (TTB to DABDT molar ratio of 1:1.5) in 90 mL N-methylpyrrolidone (NMP), 10 mL methanol, and 0.1 mL acetic acid (N-methylpyrrolidone, methanol, and acetic acid volume ratio of 9:1:0.01), and pour the solution into a clean reactor. Place carbon paper, cleaned with ethanol, at a certain angle in the reactor, then seal the reactor and place it in an oven at 170 °C for 24 hours for polymerization. After the reaction, clean and dry the carbon paper with methanol to form a COP-coated carbon paper composite material (DT-COP-CP).

[0062] S2. Dissolve 10 mg of chloroauric acid in 50 mL of deionized water and add 10 mL of triethanolamine. Transfer the DT-COP-CP composite material to the above solution. Purge the solution with argon gas for 30 minutes, then irradiate with a 300 W xenon lamp for 1 hour. After the reaction is complete, rinse thoroughly with deionized water to form the Au@DT-COP-CP composite photoelectrode.

[0063] Example 3 A photoelectrode, the preparation method of which differs from that of Example 2 is step S1: heat preservation at 160 °C for 20 hours.

[0064] Example 4 A photoelectrode, the preparation method of which differs from that of Example 2 is step S1: keeping it at 180°C for 28 hours.

[0065] Example 5 A photoelectrode, the preparation method of which differs from that of Example 2 is step S2: irradiation under a 280 W xenon lamp for 50 min.

[0066] Example 6 A photoelectrode, the preparation method of which differs from that of Example 2 is step S2: irradiation under a 320 W xenon lamp for 70 min.

[0067] Example 7 A photoelectrode, unlike Example 2, has gold nanoparticles whose mass is 0.3% of the total mass of the covalent organic polymer material modified with gold nanoparticles.

[0068] The difference between the preparation method and Example 2 is that in step S2, the mass of chloroauric acid is 5 mg.

[0069] Example 8 A photoelectrode, unlike Example 2, has gold nanoparticles whose mass is 0.7% of the total mass of the covalent organic polymer material modified with gold nanoparticles.

[0070] The difference between the preparation method and Example 2 is that in step S2, the mass of chloroauric acid is 15 mg.

[0071] Comparative Example 1 A covalent organic polymer material is prepared by the following steps: 120 mg DABDT and 133.2 mg TTB are dissolved in 90 mL of N-methylpyrrolidone (NMP), 10 mL of methanol, and 0.1 mL of acetic acid, and the solution is poured into a clean reaction vessel. The reaction vessel is then sealed and placed in an oven at 170 °C for 24 hours. After the reaction is complete, the mixture is washed with methanol and dried to form the DT-COP covalent organic polymer material.

[0072] The difference from Example 1 is that step S2 is not included.

[0073] Comparative Example 2 A photoelectrode is prepared by the following steps: 120 mg DABDT and 133.2 mg TTB are dissolved in 90 mL of N-methylpyrrolidone (NMP), 10 mL of methanol, and 0.1 mL of acetic acid, and the solution is poured into a clean reaction vessel. Carbon paper, cleaned with ethanol, is placed at a certain angle in the reaction vessel, which is then sealed and placed in an oven at 170 °C for 24 hours. After the reaction is complete, the paper is cleaned with methanol and dried to form a DT-COP-CP composite photoelectrode.

[0074] The difference from Example 2 is that step S2 is not included.

[0075] Result detection Solar seawater battery assembly: The solar seawater battery consists of two main components: electrodes and electrolyte. The photoelectrode and zinc metal in each embodiment and comparative example form the two electrodes of the battery, and seawater serves as the electrolyte and is connected to the components.

[0076] Photocurrent performance testing: The solar-powered seawater cell, light source, spectrometer, and electrochemical workstation were connected for testing; a xenon lamp with an AM 1.5 filter was used as a simulated sunlight source, and the output power was controlled at 100 mW·cm⁻¹. -2 The photoelectrode was illuminated by a lamp source, and the photocurrent response characteristics of the solar-powered seawater cell were recorded using an electrochemical workstation.

[0077] Performance test data are shown in Table 1-4 below. Figures 1-9 As shown.

[0078] (1) The electrode potential E / V vs. Zn / Zn of the photoelectrode in Examples 2-8 during charging compared to the zinc ion standard electrode. 2+ The test results are shown in Table 1 below.

[0079] Table 1. Charging performance of solar-powered seawater batteries with photoelectrodes in Examples 2-8

[0080] (2) The electrode potential E / V vs. Zn / Zn during photoelectrode discharge in Examples 2-8 compared to the zinc ion standard electrode. 2+ The test results are shown in Table 2 below.

[0081] Table 2. Discharge performance of solar-powered seawater batteries composed of photoelectrodes in Examples 2-8

[0082] (3) Test the electrode potential E / V of the zinc ion standard electrode when the photoelectrode of Example 2 and Comparative Example 2 is charged compared with that of the zinc ion standard electrode. 2+ The test results are shown in Table 3 below.

[0083] Table 3. Charging performance of solar-powered seawater batteries composed of photoelectrodes in Example 2 and Comparative Example 2

[0084] Under the condition of achieving the same current density (J), compared with Comparative Example 2, the E / V vs. Zn / Zn ratio of Example 2 is... 2+ The lower voltage indicates that the photoanode of Example 2 can achieve the same current density at a lower charging voltage, and Example 2 has better charging performance than Comparative Example 2.

[0085] (4) Test the electrode potential E / V of the zinc ion standard electrode compared to that of Example 2 and Comparative Example 2 during photoelectrode discharge. 2+ The test results are shown in Table 4 below.

[0086] Table 4. Discharge performance of solar-powered seawater batteries composed of photoelectrodes in Example 2 and Comparative Example 2

[0087] Under the condition of achieving the same current density (J), compared with Comparative Example 2, the E / V vs. Zn / Zn ratio of Example 2 is... 2+ The higher voltage indicates that the photoanode of Example 2 can achieve the same current density at a higher discharge voltage, and Example 2 has better discharge performance than Comparative Example 2.

[0088] As can be seen from the data of Example 2 and Comparative Example 2 in Tables 3 and 4, the photoelectrode Au@DT-COP-CP material provided in Example 2 of the present invention can indeed be used as the photoelectrode of a solar seawater battery, and the charge and discharge performance of the solar seawater battery is improved under illumination conditions.

[0089] Figure 1 The images shown are SEM images of the photoelectrode provided in Embodiment 2 and Comparative Example 2 of the present invention, TEM images provided in Embodiment 2, and a gold particle size distribution map. From... Figure 1 As can be seen from Example 2, gold nanoparticles cover the surface of the carbon fiber COP layer, and the average particle size of the gold nanoparticles ranges from 2.3 to 8.9 nm.

[0090] Figure 2 The images show the XRD patterns of the photoelectrodes provided in Embodiment 2 and Comparative Example 2 of the present invention. Figure 2The successful synthesis of Au@DT-COP-CP material in Example 2 can be confirmed. Diffraction peaks are clearly shown at 38.10, 44.36, 64.54 and 77.48 degrees, corresponding to the (111), (200), (220) and (311) planes of Au, indicating that the characteristic peaks of gold are fully displayed.

[0091] Figure 3 The hydrophobicity angle diagrams provided in Embodiment 2 and Comparative Example 2 of the present invention are shown. Figure 3 As can be seen, the contact angle between the material DT-COP-CP in Comparative Example 2 and the water droplet was measured to be 134.6°, while the contact angle of the material Au@DT-COP-CP in Example 2 decreased to 105.8°, indicating that the incorporation of gold nanoparticles enhanced the hydrophilicity of the material.

[0092] Figure 4 The BET diagrams provided in Embodiment 1 and Comparative Example 1 of the present invention are shown below. Figure 4 As can be seen, the specific surface area of ​​material DT-COP in Comparative Example 1 is 4.04 m². 2 / g, the specific surface area of ​​the material Au@DT-COP in Example 1 is 9.13 m². 2 / g, the specific surface area of ​​the material increases, which indicates that the material can provide more active sites.

[0093] Figure 5 The carbon NMR spectrum of the DT-COP prepared according to Comparative Example 1 of this invention. Figure 6 The infrared spectra of DT-COP, DABDT, and TTB prepared according to Comparative Example 1 of this invention are shown. In the FT-IR spectrum of TTB, a phenomenon at 1660 cm⁻¹ attributed to the C=O stretching vibration was observed. 1 A significant absorption peak is observed at 2457 cm⁻¹, while this peak is almost absent in the spectrum of DT-COP. The FT-IR spectrum of DABDT shows a peak at 2457 cm⁻¹. -1 The characteristic absorption peak at 862 cm⁻¹ corresponds to the SH stretching vibration, which disappears in DT-COP. The FT-IR spectrum of DT-COP shows a peak at 862 cm⁻¹. -1 The CSC stretching vibration at the point indicates the formation of a thiazole ring. It can be seen that Comparative Example 1 of this invention successfully synthesized the covalent organic polymer DT-COP.

[0094] Figure 7 The graphs show the photoelectric performance of the photoelectrodes provided in Embodiment 2 and Comparative Example 2 of this invention. The DT-COP-CP is 59 µA·cm. 2 The photoresponse current of Au@DT-COP-CP is 74 µA·cm. 2The reproducible and stable photocurrent was obtained, with a 25% increase in photocurrent. It can be seen that loading gold nanoparticles can effectively improve the photoresponse current intensity of the material.

[0095] Figure 8 The images show the cycle stability test results of the solar-powered seawater battery prepared using the photoelectrode provided in Example 2 of this invention, as well as the SEM image of the photoelectrode after the test. Figure 8 As can be seen, the photoelectrode provided by this invention has extremely strong cycle stability in seawater batteries. After 108 cycles, the battery voltage remains basically unchanged, and the microstructure of the photoanode does not change significantly.

[0096] Figure 9 The image shows the XRD pattern of the photoelectrode after cycle stability testing of the solar seawater battery prepared using the photoelectrode provided in Example 2 of this invention. Figure 9 As can be seen, the structure of Au on the photoelectrode surface did not change after 108 cycles of stability testing.

[0097] Figure 10 This is a schematic diagram of the preparation process in Embodiment 2 of the present invention. Figure 10 As can be seen from the present invention, the DT-COP provided by the present invention has repeating units composed of DABDT and TTB.

[0098] Figure 11 This is a schematic diagram of the photoelectrode operation provided in Embodiment 2 of the present invention. Figure 11 As can be seen, gold and DT-COP form a Schottky junction due to the difference in work function, thus constructing a built-in electric field. Under illumination, gold generates hot electrons, which are transferred from gold to the conduction band of DT-COP under the influence of the built-in electric field. This indicates that the gold and DT-COP heterojunction structure provided by this invention, where the LSPR and Schottky junction synergistically promote the effective separation of electron-hole pairs within the photoelectrode.

[0099] In summary, the gold nanoparticle-modified covalent organic polymer material of this invention is a semiconductor material with high photogenerated charge separation efficiency, ultrafast interfacial electron transport kinetics, and excellent catalytic performance.

[0100] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A covalent organic polymer material modified with gold nanoparticles, characterized in that, This includes covalent organic polymers and gold nanoparticles loaded on the surface of covalent organic polymers; The covalent organic polymer has repeating units with the following structure: The average particle size of the gold nanoparticles is 2.3–8.9 nm; The mass of the gold nanoparticles is 0.3 to 0.7% of the total mass of the covalent organic polymer material modified with the gold nanoparticles.

2. The covalent organic polymer material modified with gold nanoparticles as described in claim 1, characterized in that, The covalent organic polymer is obtained by polymerization of two monomers, 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride.

3. A photoelectrode, characterized in that, It includes a substrate and a catalyst supported on the substrate, wherein the catalyst is a covalent organic polymer material modified with gold nanoparticles as described in claim 1 or 2.

4. The photoelectrode as described in claim 3, characterized in that, The substrate is hydrophilic carbon paper.

5. The method for preparing the photoelectrode as described in claim 3 or 4, characterized in that, Includes the following steps: S1. 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride were polymerized on a substrate to obtain a covalent organic polymer-coated substrate composite material. S2. The photoelectrode is obtained by irradiating the mixed solution of the covalent organic polymer-coated substrate composite material, chloroauric acid, and triethanolamine obtained in step S1 with a xenon lamp; In step S1, the molar ratio of 5,5',5''-(benzene-1,3,5-triyl)tris(thiophene-2-carboxaldehyde) and 2,5-diamino-1,4-benzenedithiol dihydrochloride is 1:(1~2); the polymerization temperature is 140~200℃, and the polymerization time is 8~32h; In step S2, the power of the xenon lamp is 240~360W, and the irradiation time is 30~90min.

6. The method for preparing the photoelectrode as described in claim 5, characterized in that, In step S1, the polymerization reaction temperature is 160~180℃ and the polymerization reaction time is 20~28h.

7. The method for preparing the photoelectrode as described in claim 5, characterized in that, In step S2, the power of the xenon lamp is 280~320W, and the irradiation time is 50~70min.

8. The method for preparing the photoelectrode as described in claim 5, characterized in that, In step S1, the mixed organic solvent A includes A1, A2 and A3, wherein A1 is N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, A2 is methanol, ethanol or n-butanol, and A3 is acetic acid, and the volume ratio of A1:A2:A3 is (8~10):(0.9~1.1):(0.01~0.03).

9. A solar-powered seawater battery, characterized in that, It includes a photoelectrode, a metal electrode, and an electrolyte connecting the photoelectrode and the metal electrode, wherein the photoelectrode is the photoelectrode according to claim 3 or 4.

10. The solar-powered seawater battery as described in claim 9, characterized in that, The metal electrode is made of zinc, sodium, aluminum, or magnesium.

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