Charging and discharging of copper-plated titanium dioxide nanotube antifouling material, its preparation method and application

Abstract

The application provides a preparation method of a chargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material, adopts an anodic oxidation method to prepare TNT, uses a colloidal silver activation solution to activate the TNT, adopts a method of reducing CuSO4 by formaldehyde to perform copper plating treatment on the TNT, and obtains copper-doped TNT nanotubes. 2+ The material is based on CuO or Cu2O loaded on a titanium dioxide nanotube array, the TNT-Cu is used for antifouling on Phaeodactylum tricornutum for the first time, and through the synergistic effect of the capacitance effect and the controllable Cu 2+ slow release, the adhesion inhibition rate of the Phaeodactylum tricornutum reaches 98.3+ / -0.87%, the mortality rate reaches 96.0+ / -2.0%, and efficient, persistent and environment-friendly antifouling on the Phaeodactylum tricornutum is achieved.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials technology, and particularly relates to a method for preparing and applying a rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material. Background Technology

[0002] Marine engineering facilities are exposed to complex aquatic environments for extended periods, facing fouling problems caused by the dynamic succession of biological communities. Biofouling processes typically include: conditioned film formation, biofilm attachment, plankton aggregation, and colonization by macroheterotrophic organisms. Existing research indicates that controlling early biofilm formation is crucial. Among these, *Phaeodactylum tricornutum*, as a pioneer fouling organism, promotes subsequent colonization by secreting extracellular polymeric substances (EPS), seriously threatening equipment performance and safety.

[0003] Current antifouling technologies mainly fall into three categories, all of which have significant drawbacks. The first type is based on TiO2 photocatalytic materials, such as Ag / TiO2 heterojunctions. These rely on ultraviolet light to excite reactive oxygen species (ROS) to inhibit algal growth. However, the limited penetration depth of ultraviolet light in marine environments leads to a significant decrease in photocatalytic efficiency and poor applicability to marine environments. The second type uses capacitive carbon-based electrodes, such as graphene electrodes. These interfere with electron transfer in microorganisms through surface charge, but their inhibition rate against microalgae such as *Phaeodactylum tricornutum* is generally below 50%, and the purely physical mechanism lacks the ability to destroy the EPS adhesion layer. The third type uses enzyme-immobilized coatings, such as enzyme-immobilized titanium dioxide nanotube antifouling coatings. These coatings degrade the algal EPS adhesion layer through the enzymatic hydrolysis of algal immobilized alkaline proteases. However, enzyme activity is easily affected by fluctuations in seawater pH and temperature, making it difficult to maintain long-term effective activity in long-term marine immersion environments. Furthermore, the nanotube structure is easily blocked by biofilms, leading to functional failure and poor antifouling durability.

[0004] Therefore, there is an urgent need to develop long-lasting antifouling materials that can effectively inhibit microalgae attachment and adapt to harsh marine environments to ensure the safe operation of facilities. Summary of the Invention

[0005] To overcome the above problems, this invention provides a rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a method for preparing a rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material, comprising the following steps: (1) Pretreatment: The titanium foil was immersed in HCl, and then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in sequence, and dried for later use. (2) First-time anodizing: Ti sheet is used as the anode and graphite electrode is used as the cathode. In an electrolyte solution composed of ammonium fluoride, ethylene glycol and deionized water, the anode is anolyzed for a period of time at a certain voltage. Then, it is placed in HCl solution for ultrasonic treatment to obtain Ti sheet, which is then dried for later use. (3) Secondary anodizing: Under the same conditions as primary anodizing, secondary anodizing is performed for a period of time to obtain a highly ordered TNT structure, and then annealed at a certain temperature to obtain a crystallized TNT array film; (4) TNT activation: First, weigh out trisodium citrate dihydrate and dissolve it in deionized water, then add stannous sulfate, then add silver nitrate solution diluted with deionized water, replenish deionized water, and then obtain colloidal silver activation solution by ultrasonic treatment. Place the TNT sample in the colloidal silver activation solution and stir in a water bath at a certain temperature to obtain surface-activated TNT. (5) Chemical copper plating: In a plating solution composed of CuSO4·5H2O, Na2EDTA·2H2O, NaOH and deionized water, activated TNT is placed in the copper plating solution, and formaldehyde is added. The solution is stirred in a water bath at a certain temperature. During the copper plating process, NaOH solution is added dropwise to stabilize the pH value of the plating solution between 11 and 12. After copper plating is completed, the sample is removed from the plating bath and washed with Na2EDTA solution to remove residual Cu. 2+ Then, it was washed with deionized water until the pH value was equal to 7, and finally washed with anhydrous ethanol to obtain copper-doped TNT nanotubes.

[0007] In one or more embodiments, in step (1), the titanium foil is immersed in 1 mol / L HCl for 2.5-3 hours, and then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 10-15 minutes each.

[0008] In one or more embodiments, in step (2), each liter of electrolyte contains 3.44 g of ammonium fluoride, 900 mL of ethylene glycol and 100 mL of deionized water; The voltage for anodizing is 40~60 V, and the anodizing time is 1~2 hours; Sonicate in 0.7 mol / L HCl solution for 1 h.

[0009] In one or more embodiments, in step (3), the voltage for anodizing is 40~60 V and the time for anodizing is 1~2 h; The annealing temperature is 300–500℃, and the annealing time is 2–4 hours.

[0010] In one or more embodiments, in step (4), 9.8-10.0g of trisodium citrate dihydrate is weighed and dissolved in deionized water, then 4.2-4.4g of stannous sulfate is added, 3.5-4.5mL of silver nitrate solution with a concentration of 16-18g / L is taken, and deionized water is added to dilute to 4.5-5.5mL, and deionized water is added to make the total volume of the solution reach 190-210mL; The water bath stirring temperature is 35-40℃, and the stirring time is 8-10 minutes.

[0011] In one or more embodiments, in step (5), 3.6-4g CuSO4·5H2O, 8-9g Na2EDTA·2H2O and 4-5g NaOH are dissolved in deionized water, the resulting solution is stirred and mixed, and deionized water is added to the target volume. The solution is then ultrasonically dispersed for 1-2 min. Place 0.1-0.3 g of activated TNT into the copper plating solution; Add 4-5 mL of formaldehyde, and stir in a water bath at 60-70°C for 8-10 minutes.

[0012] In a second aspect, the present invention provides a rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material, which is prepared by the preparation method described in the first aspect, wherein CuO or Cu2O is supported on a titanium dioxide nanotube array as a substrate.

[0013] In one or more embodiments, the root mean square roughness of the antifouling material is 190–210 nm.

[0014] A third aspect of the invention provides the application of the rechargeable copper-plated titanium dioxide nanotube antifouling material described in the second aspect in marine antifouling, the application including the use of uncharged or charge-discharge treated copper-plated titanium dioxide nanotube antifouling material in the antifouling of *Phaeodactylum tricornutum*.

[0015] In one or more embodiments, copper-plated titanium dioxide nanotube antifouling material treated with charge-discharge process is used for antifouling of *Phaeodactylum tricornutum*. TNT-Cu with attached brown finger algae was used as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. The electrode was charged at 0.5–2V for 10–15 min, followed by a discharge treatment for 10–15 min.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) The rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material provided by this invention significantly improves the capacitance performance of TNT-Cu through the synergistic effect of the porous structure of TNT and Cu doping. This invention is the first to use TNT-Cu for antifouling of *Phaeodactylum tricornutum*, utilizing the capacitance effect and controllable Cu... 2+ The synergistic effect of slow release: after charging, the surface charge disrupts the electron transport chain of algal cells, simultaneously promoting the release of Cu from surface CuO / Cu2O. 2+ It induces the accumulation of ROS in microalgal cells, achieving an attachment inhibition rate of 98.3±0.87% and a mortality rate of 96.0±2.0% against *Phaeodactylum tricornutum*, thus achieving highly efficient antifouling against *Phaeodactylum tricornutum*.

[0017] (2) Environmental toxicity is controllable and lower than that of traditional antifouling coatings; static immersion for 3 days (Cu) 2+ The leaching amount is ≤5 mg / L, and the electrolyte leaching amount after charging is ≤8 mg / L. By controlling the leaching rate through the charge-discharge cycle, the risk of exceeding environmental toxicity standards can be effectively reduced.

[0018] (3) The rechargeable copper-plated titanium dioxide nanotube antifouling material provided by the present invention has a Cu atomic ratio of 10.8% in the inner layer, indicating that the coating is tightly bonded to the TNT substrate, and the risk of erosion and peeling is reduced compared with general antifouling coatings. EIS test proves that the material has certain recyclability, and the estimated algae inhibition rate maintenance rate is high, and the antifouling life is significantly extended compared with enzyme immobilized coatings. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, 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 improper limitation of the invention.

[0020] Figure 1 Morphology, elemental composition, and roughness characterization of TNT-Cu in Example 1; Figure 1 (a) is a SEM image of TNT-Cu in Example 1; Figure 1 (b) is Figure 1 (a) Enlarged SEM image; Figure 1 (c) is a SEM image of the TNT-Cu inner layer in Example 1; Figure 1 (d) is a graph showing the EDS analysis results of TNT-Cu in Example 1; Figure 1 (e) is the AFM chromatogram of TNT-Cu in Example 1; Figure 1 (f) is the frequency distribution histogram of TNT-Cu in Example 1 using AFM; Figure 2 The XPS spectrum of TNT-Cu in Example 1; Figure 2 (a) is the XPS spectrum of TNT-Cu in Example 1; Figure 2 (b) XPS analysis of Ti 2p peaks in TNT-Cu from Example 1; Figure 2 (c) XPS Cu 2p peak analysis of TNT-Cu in Example 1; Figure 2 (d) XPS C 1s peak analysis of TNT-Cu in Example 1; Figure 3 This is a diagram illustrating the preparation process of TNT-Cu in Example 1; Figure 4 The electrochemical performance of TNT-Cu in Example 1; Figure 4 (a) Cyclic voltammetry (CV) curves at different scan rates; Figure 4 (b) Comparison of CV (0.1 V / s) between TNT-Cu electrode and titanium (Ti) electrode; Figure 4 (c) shows the constant current discharge (GCD) curves under different current densities; Figure 4 (d) Comparison of GCD between TNT-Cu electrode and titanium (Ti) electrode (1 mA / cm²) 2 ); Figure 5 The EIS test results of the TNT-Cu sample and Ti sheet in Example 1 before and after charge and discharge; Figure 5 (a) is the equivalent circuit diagram of the reference Ti chip; Figure 5 (b) is the equivalent circuit diagram of the TNT-Cu sample; Figure 5 (c) is the Bode plot of the control sample Ti; Figure 5 (d) is the Nyquist plot of the control sample Ti. Figure 5 (e) is the Bode plot of the TNT-Cu sample; Figure 5 (f) is the Nyquist plot of the TNT-Cu sample; Figure 6 (a) Correspondence between absorbance and *NP. trigonelnutum*; Figure 6 (b) is a graph showing the changes in absorbance during the growth of *Phaeodactylum tricornutum*. Figure 6 (c) is a diagram showing the pH changes during the growth of *Phaeodactylum tricornutum*. Figure 7 The results of fluorescence staining of TNT-Cu samples and Ti sheets after antifouling treatment in Example 1, the attachment inhibition rate of *Phaeodactylum tricornutum*, and the mortality rate of *Phaeodactylum tricornutum* are shown. Figure 7 (a) is a CLSM diagram of an uncharged Ti wafer; Figure 7 (b) is the CLSM diagram of the Ti wafer after charging and discharging; Figure 7 (c) CLSM plot of uncharged TNT-Cu sample; Figure 7(d) is the CLSM image of the TNT-Cu sample after charge and discharge; Figure 7 (e) shows the adhesion inhibition rate of the Ti sheet after charging and discharging, the uncharged TNT-Cu sample, and the TNT-Cu sample after discharging on the brown finger algae. Figure 7 (f) The mortality rates of *Phaeodactylum tricornutum* were observed in Ti sheets after charging and discharging, uncharged TNT-Cu samples, and discharged TNT-Cu samples, respectively. Figure 8 SEM image of the TNT-Cu surface after antifouling treatment; Figure 8 (a) SEM image of an uncharged TNT-Cu sample; Figure 8 (b) is a SEM image of the TNT-Cu sample after charge and discharge; Figure 9 (a) Cu in the TNT-Cu of Example 1 during the antifouling process 2+ Dissolution rate variation graph; Figure 9 (b) shows the compound morphology and distribution of copper on the TNT-Cu surface in Example 1. Detailed Implementation

[0021] Example 1 Preparation of a rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material: (1) Pretreatment: Titanium foil (Ti) with dimensions of 10 mm × 10 mm × 0.1 mm was immersed in 1 mol / L HCl for 3 h, and then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in sequence, and dried for later use. (2) One-time anodizing: A two-electrode system was used, with Ti sheet as the anode and graphite electrode as the cathode. The electrolyte solution was an organic solvent system (each liter of electrolyte contained 3.44 g ammonium fluoride, 900 mL ethylene glycol and 100 mL deionized water). The distance between the anode and cathode was 1 cm. A constant voltage of 60 V was applied between the anode and cathode using a DC power supply system to perform anodizing treatment on the Ti sheet. After 1 hour, the Ti sheet was placed in a 0.7 mol / L HCl solution and ultrasonically treated for 1 hour to remove the first oxide layer, resulting in a bright Ti sheet. The sheet was then dried for later use. (3) Secondary anodizing: The sample with the oxide film removed is subjected to a second anodizing at a constant voltage of 60 V for 1 h to obtain a highly ordered TNT structure. Then, the TNT is placed in a tube furnace at an annealing temperature of 450℃ and annealed in air atmosphere for 3 h to obtain a crystallized TNT array film. (4) TNT activation: Prepare a diluted silver nitrate solution in advance. Take 4 mL of 17 g / L silver nitrate and dilute it with deionized water to 5 mL. Weigh 9.91 g of trisodium citrate dihydrate and dissolve it in deionized water. Add 4.30 g of stannous sulfate and then add 5 mL of silver nitrate solution diluted with deionized water. Add deionized water to make the solution volume 200 mL. Sonicate until all substances are completely dissolved. Take 0.1 g of TNT sample and place it in the activation solution. Stir in a water bath at 35 °C for 10 min to obtain surface-activated TNT. (5) Chemical copper plating: Dissolve 3.6 g CuSO4·5H2O, 8 g Na2EDTA·2H2O and 4 g NaOH at room temperature. After stirring evenly, mix the three solutions into a 500 mL beaker. Add deionized water to make the solution volume 200 mL. Use an ultrasonic machine to disperse the plating solution for 2 min. Add 0.1 g activated TNT to the plating solution and then add 4 mL formaldehyde to start copper plating. Stir in a water bath at 60 °C for 10 min. During the reaction, add NaOH solution dropwise to keep the pH value of the plating solution stable between 11 and 12. After copper plating is completed, the sample is removed from the plating bath and washed with Na2EDTA solution to remove residual Cu. 2+ Then, it was washed with deionized water until the pH value was equal to 7, and finally washed with anhydrous ethanol. The resulting copper-doped TNT nanotubes (TNT-Cu) were stored in anhydrous ethanol.

[0022] Example 2 Preparation of a rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material: (1) Pretreatment: Titanium foil (Ti) with dimensions of 10 mm × 10 mm × 0.1 mm was immersed in 1 mol / L HCl for 3 h, and then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in sequence, and dried for later use. (2) One-time anodizing: A two-electrode system was used, with Ti sheet as the anode and graphite electrode as the cathode. The electrolyte solution was an organic solvent system (each liter of electrolyte contained 3.44 g ammonium fluoride, 900 mL ethylene glycol and 100 mL deionized water). The distance between the anode and cathode was 1 cm. A constant voltage of 60 V was applied between the anode and cathode using a DC power supply system to perform anodizing treatment on the Ti sheet. After 1 hour, the Ti sheet was placed in a 0.7 mol / L HCl solution and ultrasonically treated for 1 hour to remove the first oxide layer, resulting in a bright Ti sheet. The sheet was then dried for later use. (3) Secondary anodizing: The sample with the oxide film removed is subjected to a second anodizing at a constant voltage of 60 V for 1 h to obtain a highly ordered TNT structure. Then, the TNT is placed in a tube furnace at an annealing temperature of 450℃ and annealed in air atmosphere for 3 h to obtain a crystallized TNT array film. (4) TNT activation: Prepare a diluted silver nitrate solution in advance. Take 4 mL of 17 g / L silver nitrate and dilute it with deionized water to 5 mL. Weigh 9.91 g of trisodium citrate dihydrate and dissolve it in deionized water. Add 4.30 g of stannous sulfate and then add 5 mL of silver nitrate solution diluted with deionized water. Add deionized water to make the solution volume 200 mL. Sonicate until all substances are completely dissolved. Take 0.1 g of TNT sample and place it in the activation solution. Stir in a water bath at 35 °C for 10 min to obtain surface-activated TNT. (5) Chemical copper plating: Dissolve 4g CuSO4·5H2O, 8g Na2EDTA·2H2O and 4g NaOH under alkaline conditions and at room temperature. After stirring evenly, mix the three solutions into a 500 mL beaker, add deionized water to make the solution volume 200 mL, and use an ultrasonic machine to disperse the plating solution for 2 min. Add 0.3g activated TNT to the plating solution, and then add 4 mL of formaldehyde to start copper plating. Stir in a water bath at 60 ℃ for 10 min. During the reaction, add NaOH solution dropwise to keep the pH value of the plating solution stable between 11 and 12. After copper plating is completed, the sample is removed from the plating bath and washed with Na2EDTA solution to remove residual Cu. 2+ Then, it was washed with deionized water until the pH value was equal to 7, and finally washed with anhydrous ethanol. The resulting copper-doped TNT nanotubes (TNT-Cu) were stored in anhydrous ethanol.

[0023] Comparative Example 1 The difference from Example 1 is that step (4) is not performed, while all other conditions are the same.

[0024] As observed by scanning electron microscopy, Comparative Example 1 showed almost no sites for Cu contact adhesion on the TNT-Cu surface. This indicates that electroless copper plating without TNT activation is ineffective and its anti-fouling performance is unsatisfactory.

[0025] 1. Morphology, elemental composition, and roughness characterization of rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling materials. This invention characterizes the microstructure of the TNT-Cu sample surface using scanning electron microscopy (SEM), then carefully peels off a copper-plated thin film on the TNT-Cu surface, and finally uses SEM to characterize the microstructure of the inner layer of the sample.

[0026] This invention uses atomic force microscopy (AFM) to characterize the roughness of TNT-Cu samples.

[0027] This invention uses energy-dispersive spectroscopy (EDS) to characterize the elemental distribution of Ti, O, C, and Cu in TNT-Cu samples and to quantitatively analyze the corresponding relative atomic percentages. This invention also uses X-ray photoelectron spectroscopy (XPS) to determine the chemical state of the samples.

[0028] Characterization of the TNT-Cu prepared in Example 1: 1.1 Microstructure and Chemical Composition of TNT-Cu from Figure 1 (a) and Figure 1 (b) It can be seen that a large number of spherical particles and plate-like crystals are uniformly covered on the sample surface, combined with Figure 1 (d) EDS analysis data showed that Cu exhibited a dominant distribution on the surface, confirming the successful construction of a continuous and uniform copper coating on the TNT surface via electroless copper plating, achieving uniform Cu doping. Simultaneously, a small amount of carbon (C) was detected in the TNT-Cu sample, presumably originating from residual C from the graphite electrode and organic electrolyte during the anodizing process. This type of doping may have a positive impact on the material's capacitance performance. Figure 1 (d) It can be seen that the surface Ti content of the TNT-Cu sample is extremely low. This may be because the copper plating thickness exceeds the depth of EDS detection, causing the substrate Ti signal to be shielded and difficult to detect accurately. Furthermore, from... Figure 1 (d) It can be seen that the atomic fraction of O is much higher than that of Ti, indicating that in addition to Ti existing in the form of TiO2, Cu on the surface also exists in part in the form of oxides (CuO or Cu2O).

[0029] from Figure 1 (c) Further analysis of the microstructure of the TNT-Cu inner layer reveals a regular array of porous nanotubes exposed inside the sample after the surface coating is peeled off. This confirms that the TNT substrate formed by secondary anodizing can maintain a relatively intact structure after electroless copper plating. Uniformly distributed spherical particles can be observed on the nanotube surface and within the pores, further indicating that Cu has been deeply doped into the TNT interior. Figure 1 (d) It can be seen that the EDS analysis shows that the inner layer of the sample is still mainly composed of four elements: Ti, C, O and Cu. Among them, Ti and O are dominant, while the Cu content is reduced compared to the surface. At the same time, the atomic fraction of O is still slightly more than twice that of Ti, indicating that the main component inside the TNT-Cu sample is TiO2, possibly accompanied by some CuO or Cu2O doping.

[0030] The AFM test results were analyzed using JPK Data Processing (v 6.1.111, JPK Instruments Ltd.). Figure 1 (e) The results show that the root mean square roughness (RMS) of the sample surface is 202.0 nm, combined with Figure 1 (f) It was found that the sample surface had no obvious sharp protrusions or deep valleys, and was relatively flat overall, indicating that the coating thickness was uniformly distributed and there were few areas of abnormal thickening or thinning due to local deposition rate differences. This further confirms that the copper plating layer has good continuity and uniformity at the nanoscale. This result is consistent with the SEM characterization of the sample surface, proving that the electroless copper plating process can effectively achieve uniform loading of Cu on TNT.

[0031] like Figure 2 and Figure 9 (b) Analysis of the XPS test results shows that Ti mainly exists in TiO2, while Cu mainly exists as Cu2O and CuO oxides, with a small amount of Cu existing as Cu(OH)2. The C spectrum is basically consistent with the spectrum of exogenous carbon contamination, proving that the small amount of C doping in TNT-Cu originates from residual C from the preparation process. Therefore, TNT-Cu is mainly composed of Cu2O, CuO, and TiO2, with a small amount of Cu(OH)2 and C contaminants.

[0032] 2. Electrochemical performance of TNT-Cu This invention employs a standard three-electrode system on an electrochemical workstation, with the TNT-Cu sample used as the working electrode, and a 10 mm × 10 mm × 1 mm platinum electrode and a saturated calomel electrode (SCE) used as the counter and reference electrodes, respectively. The TNT-Cu sample was subjected to open-circuit potential (OCP) testing, cyclic voltammetry (CV) testing, galvanostatic charge-discharge (GCD) testing, and electrochemical impedance spectroscopy (EIS) testing sequentially. The OCP test lasted for 3600 s until steady state was reached. After OCP stabilization, the TNT-Cu sample underwent CV and GCD testing. The scan rates for the CV tests were set to 0.01 V / s, 0.1 V / s, 0.3 V / s, and 1 V / s, respectively, and the constant current density for the GCD tests was set to 1 mA cm⁻¹. -2 2 mA cm -2 10 mA cm -2 A new TNT-Cu sample was then used as the working electrode, and an OCP test was performed for 360 s. After the OCP stabilized, an EIS test was performed with the frequency range set to 10. 5 ~10 -2The Hz, root mean square (RMS) value of the sinusoidal voltage amplitude was set to 50 mV. Then it was charged for 15 min, discharged for 10 min, and left to stand for 1 h before being tested again with the same EIS parameters.

[0033] Pure Ti of 10 mm × 10 mm × 0.1 mm was used as the working electrode, and CV, GCD and EIS tests were performed with the same parameters as a blank control group.

[0034] Characterization of the TNT-Cu prepared in Example 1: 2.1 Capacitor Performance Analysis CV test results from Figure 4 (a) It can be seen that TNT-Cu exhibits significant high specific capacitance characteristics at different scan rates from 0.01 to 1 V / s. Furthermore, the CV curve closure area reaches its maximum value at low scan rates of 0.01 V / s and 0.1 V / s. The CV curve closure area at a scan rate of 0.01 V / s is 29.69, and at a scan rate of 0.1 V / s, the CV curve closure area is 26.71, indicating that it has high charge storage capacity. Figure 4 (b) Quantitative integral calculations show that at a scan rate of 0.1 V / s, the capacitance area of ​​TNT-Cu is 42.5 times that of pure Ti, confirming that the capacitance performance of the TNT-Cu sample is significantly improved compared to pure Ti.

[0035] GCD test results from Figure 4 (c) It can be seen that when the current density is 1 mA / cm 2 At that time, the TNT-Cu sample had the longest discharge time, reaching 146 s, and the sample capacitance reached its maximum value, significantly better than the capacitance performance under high current density. From Figure 4 (d) shows that the discharge time of the TNT-Cu sample is extended to 45.6 times that of pure Ti, which is consistent with the CV test results. This further confirms that the synergistic effect of the porous structure of TNT and Cu doping significantly improves the capacitance performance of TNT-Cu.

[0036] 2.2 EIS Analysis Figure 5The EIS test results of TNT-Cu samples and Ti sheets before and after charge / discharge are presented. Using ZSimpWin3.60 fitting calculations, the resistance values ​​of the TNT-Cu sample before and after charging in the equivalent circuit R(Q(RW))(CR) are 319.7 Ω and 371.1 Ω, respectively. The resistance values ​​of the Ti sheet before and after charging in the equivalent circuit R(CR(QR)) are 44.9 kΩ and 296.8 kΩ, respectively. Combined with the EIS analysis images, it can be observed that the resistivity of both the TNT-Cu sample and the Ti sheet increases after charging, proving that the charge / discharge treatment has a relatively small impact on the TNT-Cu sample and the Ti sheet, and that TNT-Cu has a certain degree of recyclability. The resistivity of TNT-Cu is significantly lower than that of pure Ti, which may be due to the copper plating treatment increasing the conductivity of the material surface, thus leading to a significant decrease in resistivity.

[0037] 3. Determination of standard curve and growth curve of *Phaeodactylum tricornutum* The brown finger algae were cultured to a high concentration using F / 2 medium. The F / 2 medium consisted of: 0.0748 g NaNO3, 0.0044 g NaH2PO4•H2O, 0.0013 g Na2SO3•9H2O, 1 mL of trace element solution (0.0098 g CuSO4•5H2O, 0.022 g ZnSO4•7H2O, 0.01 g CoCl2•6H2O, 0.18 g MnCl2•4H2O, 0.0063 g Na2MoO4•2H2O, 4.37 g Na2EDTA, 3.15 g FeCl3•6H2O, 100 mL of simulated seawater), 1 mL of vitamin solution (0.005 g vitamin B12, 0.1 g vitamin B1, 0.005 g vitamin H, 1000 mL of deionized water), and 1000 mL of simulated seawater. The algal solution was diluted at different ratios, and the absorbance of the algal solutions at different dilutions was measured at a wavelength of 686 nm using a microplate reader. Simultaneously, the number of microalgae corresponding to different dilutions was counted using flow cytometry after staining with Green I dye.

[0038] Five parallel groups (each containing 300 mL of algal solution) and one blank control group (containing 300 mL of algal solution, with one 10 mm × 10 mm × 0.1 mm pure Ti tablet soaked in it) were set up and cultured in a shaking incubator under light (12% illumination, 12:12 h light-dark cycle, 50 rpm rotation, and 20 °C). 4 mL of algal solution was collected every 24 h, ensuring the solution was well mixed before sampling. 1.5 mL of algal solution was used to measure absorbance at 686 nm using a microplate reader, with five measurements taken for each sample. 2.5 mL of algal solution was used to measure pH using a pH meter, with three measurements taken for each sample. Measurements were performed continuously for 14 days.

[0039] Absorbance and number of Phaeodactylum tricornutum (N) P.tricornutum The correspondence between them is as follows: Figure 6 As shown in (a). From the fitted image, it can be seen that absorbance is related to N. P.tricornutum They exhibit a linear positive correlation, with a correlation coefficient R. 2 It is 0.9995. Figure 6 (b) and Figure 6 (c) Shows the changes in absorbance and pH during the growth of *Phaeodactylum tricornutum* under normal conditions (normal group) and in the presence of Ti plates (Ti control group) over 14 days. Figure 6 (b) and Figure 6 (c) It can be seen that the algal solution concentration reached a high level on the 3rd day, indicating that the environmental adaptation period of the brown finger algae is about 3 days. Subsequently, the absorbance and pH value showed an overall increasing trend over time. No obvious logarithmic growth phase and steady growth phase were observed during its growth process.

[0040] Comparison of the growth curves of the normal group and the Ti control group revealed that although the absorbance and pH value of *Phaeodactylum tricornutum* were generally lower in the presence of Ti tablets compared to normal conditions, this difference is likely due to the different initial algal solution concentrations used. Overall, the growth curve trends of the Ti control group and the normal group were almost identical, and there was no significant difference in the pH fluctuation range between the two groups over 14 days. This demonstrates that *Phaeodactylum tricornutum* grew well under both conditions, and that Ti itself had no significant inhibitory effect on the long-term growth and metabolism of *Phaeodactylum tricornutum*, exhibiting good biocompatibility.

[0041] 4. Analysis of the antifouling performance of TNT-Cu prepared in Example 1 Treatment of *Phaeodactylum triangularis* attachment: Twelve parallel groups were set up, with each group using 10 mL of algal solution in a 50 mL centrifuge tube to soak a 10 mm × 10 mm × 0.1 mm TNT-Cu sample. Twelve blank control groups were also set up, with each group using 10 mL of algal solution in a 50 mL centrifuge tube to soak a 10 mm × 10 mm × 0.1 mm pure Ti sample. The samples were incubated for three days in a light incubator (12% illumination, 12:12 h light / dark cycle, 20 °C). Every 24 h, 2 mL of the algal solution used to soak the TNT-Cu sample was collected and stored at 4 °C for subsequent Cu... 2+ Dissolution rate detection.

[0042] Fluorescent staining test: The anti-algae effect of TNT-Cu samples coated with *Phaeodactylum tricornutum* was evaluated using a multiplex fluorescence staining method, both before and after charging and discharging. An electrochemical workstation with a three-electrode system was used. The TNT-Cu samples coated with *Phaeodactylum tricornutum* or Ti sheets were used as the working electrode, and a 10 mm × 10 mm × 1 mm platinum electrode and a SCE were used as the counter and reference electrodes, respectively. The three groups of samples and three groups of titanium sheets were charged for 15 min and then discharged for 10 min. The electrolyte from the TNT-Cu samples was collected and stored at 4 °C for subsequent Cu... 2+ Dissolution rate detection.

[0043] Under room temperature and dark conditions, three groups of uncharged and three groups of charged / discharged TNT-Cu samples and Ti slides with attached *Phaeodactylum tricornutum* were stained for 15 min each using the LIVE / DEAD® BacLight™ bacterial viability kit (SYTO-9 and propidium iodide (PI) staining solution). (The samples were soaked in PBS buffer for 2 min before staining). The morphology, activity, and metabolic changes of *Phaeodactylum tricornutum* were then observed using an upright fluorescence microscope. In the fluorescence images, live algal cells were stained green, and dead algal cells were stained red.

[0044] Morphological characterization of anti-algae effect: The *Phaeodactylum tricornutum* species attached to the surfaces of TNT-Cu samples and Ti sheets after uncharged and charge / discharge conditions were observed using SEM. Prior to observation, the samples were pretreated using a biofilm fixation process. First, the samples were pretreated in 2.5% (v / v) glutaraldehyde at 4 °C for 8 h, then sequentially dehydrated in 50%, 60%, 70%, 80%, 90%, 95%, and 100% (v / v) ethanol solutions for 10 min each, and dried for later use. The dehydrated sample surfaces were then sputter-coated with gold, and high-resolution SEM was used to observe the morphology, activity, and metabolic changes of *Phaeodactylum tricornutum* on the TNT-Cu samples and Ti sheets after uncharged and charge / discharge conditions.

[0045] Cu in the antifouling process 2+ Dissolution determination: Atomic absorption spectrometry (AAS) was used to analyze the Cu content of TNT-Cu samples in the algal solution used during the adhesion treatment (immersion for 1 day, 2 days, and 3 days) and the electrolyte used during the charge-discharge process. 2+ Content detection, determining Cu during the antifouling process. 2+ Dissolution amount.

[0046] 4.1 Characterization of antifouling effect Figure 7 (a) ~ Figure 7 (d) The fluorescence staining results of Ti sheets and TNT-Cu samples after antifouling treatment are shown. From Figure 7 (a) It can be seen that the uncharged Ti sheet exhibits a large area of ​​green fluorescence, indicating the presence of a large number of live algal cells attached to it. From Figure 7 (b) It can be seen that the proportion of live algal cells on the surface of the Ti sheet decreased slightly after charging and discharging. Figure 7 (e) and Figure 7 (f) It can be seen that the Ti sheet after charging and discharging has an adhesion inhibition rate of 62.0±1.7% on Phaeodactylum tricornutum, but still shows a lot of green fluorescence signals. The mortality rate of Phaeodactylum tricornutum is only 29.8±1.4%, and the coverage rate of live algae is still high. This indicates that the Ti sheet with simple charging and discharging treatment has limited antifouling effect on Phaeodactylum tricornutum.

[0047] In contrast, from Figure 7 (c) Figure 7 (e) and Figure 7 (f) It can be seen that the uncharged TNT-Cu sample showed a significant decrease in green fluorescence intensity, a significant increase in attachment inhibition rate (88.8±3.36%), and an increase in the mortality rate of *Phaeodactylum tricornutum* (58.7±1.1%). Meanwhile, from... Figure 8 The SEM image of (a) also shows that the *Phaeodactylum tricornutum* cells on its surface are mostly shrunken, and the coverage of live algae is lower than that of pure Ti, indicating that the copper plating and TNT structure itself have certain anti-algae activity. After further charge-discharge treatment, from Figure 7 (d) Figure 7 (e) and Figure 7 (f) It can be seen that the TNT-Cu surface showed almost no green fluorescence signal, the attachment inhibition rate reached 98.3±0.9%, and the mortality rate of *Phaeodactylum tricornutum* was as high as 96.0±2.0%. Figure 8 (b) The SEM image shows that the algal cell structure is severely shrunken and even broken, indicating that there are very few live algal cells remaining on the surface of the TNT-Cu sample after charging and discharging, which confirms the capacitance-dependent antifouling performance of the TNT-Cu sample.

[0048] 4.2 Cu in the antifouling process 2+ Dissolution amount Cu in the antifouling process of TNT-Cu 2+ Changes in dissolution rate as follows Figure 9 As shown, the first three data points (Day1, Day2, Day3) represent the Cu content in the algal solution after 1, 2, and 3 days of TNT-Cu immersion during the attachment treatment process, respectively. 2+ Dissolution amount, the last data point (Electrolyte) represents the Cu in the electrolyte after TNT-Cu charge-discharge treatment. 2+ Dissolution rate. It can be seen that as the soaking time increases, the Cu in the algal solution... 2+ The increasing trend in leaching demonstrates that uncharged TNT-Cu can partially dissolve Cu. 2+ This inhibits the attachment of free microalgae, thereby reducing the adhesion of *Phaeodactylum tricornutum*. After charge-discharge treatment, the Cu in the electrolyte... 2+ The significant increase in dissolution indicates that TNT-Cu may synergistically promote Cu dissolution through its capacitive properties during charge and discharge. 2+ The release of [something] results in superior antifouling performance.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present 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 rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material, characterized in that, Includes the following steps: (1) Pretreatment: The titanium foil was immersed in HCl, and then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water in sequence, and dried for later use. (2) First-time anodizing: Ti sheet is used as the anode and graphite electrode is used as the cathode. In an electrolyte solution composed of ammonium fluoride, ethylene glycol and deionized water, the anode is anolyzed for a period of time at a certain voltage. Then, it is placed in HCl solution for ultrasonic treatment to obtain Ti sheet, which is then dried for later use. (3) Secondary anodizing: Under the same conditions as primary anodizing, secondary anodizing is performed for a period of time to obtain a highly ordered TNT structure, and then annealed at a certain temperature to obtain a crystallized TNT array film; (4) TNT activation: First, weigh out trisodium citrate dihydrate and dissolve it in deionized water, then add stannous sulfate, then add silver nitrate solution diluted with deionized water, replenish deionized water, and then obtain colloidal silver activation solution by ultrasonic treatment. Place the TNT sample in the colloidal silver activation solution and stir in a water bath at 35-40℃ for 8-10 minutes to obtain surface-activated TNT. (5) Chemical copper plating: In a plating solution composed of CuSO4·5H2O, Na2EDTA·2H2O, NaOH and deionized water, activated TNT is placed in the copper plating solution, and formaldehyde is added. The solution is stirred in a water bath at 60-70℃ for 8-10 minutes. During the copper plating process, NaOH solution is added dropwise to stabilize the pH value of the plating solution between 11 and 12. After copper plating is completed, the sample is removed from the plating bath and washed with Na2EDTA solution to remove residual Cu. 2+ Then, it was washed with deionized water until the pH value was equal to 7, and finally washed with anhydrous ethanol to obtain copper-doped TNT nanotubes, TNT-Cu. The Cu element mainly exists in the form of two oxides, Cu2O and CuO. During the charge and discharge process, TNT-Cu promotes Cu production through its capacitance characteristics. 2+ The release.

2. The method for preparing the rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material as described in claim 1, characterized in that, In step (1), the titanium foil is immersed in 1 mol / L HCl for 2.5-3 hours, and then ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 10-15 minutes each.

3. The method for preparing the rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material as described in claim 1, characterized in that, In step (2), each liter of electrolyte contains 3.44 g of ammonium fluoride, 900 mL of ethylene glycol, and 100 mL of deionized water; The voltage for anodizing is 40~60 V, and the anodizing time is 1~2 hours; Sonicate in 0.7 mol / L HCl solution for 1 h.

4. The method for preparing the rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material as described in claim 1, characterized in that, In step (3), the voltage for anodizing is 40~60 V, and the anodizing time is 1~2 h; The annealing temperature is 300–500℃, and the annealing time is 2–4 hours.

5. The method for preparing the rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material as described in claim 1, characterized in that, In step (4), weigh 9.8-10.0g of trisodium citrate dihydrate and dissolve it in deionized water, then add 4.2-4.4g of stannous sulfate, take 3.5-4.5mL of silver nitrate solution with a concentration of 16-18g / L, add deionized water to dilute to 4.5-5.5mL, and add deionized water to make the total volume of the solution reach 190-210mL.

6. The method for preparing the rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material as described in claim 1, characterized in that, In step (5), 3.6-4g CuSO4·5H2O, 8-9g Na2EDTA·2H2O and 4-5g NaOH are dissolved in deionized water, and the resulting solution is stirred and mixed. Deionized water is added to the target volume and ultrasonically dispersed for 1-2 min. Place 0.1-0.3 g of activated TNT into the copper plating solution; Add 4-5 mL of formaldehyde.

7. A rechargeable and dischargeable copper-plated titanium dioxide nanotube antifouling material prepared by any one of claims 1-6, characterized in that, CuO or Cu2O is supported on a titanium dioxide nanotube array as a substrate.

8. The rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material as described in claim 7, characterized in that, The root mean square roughness of the antifouling material is 190–210 nm.

9. The application of the rechargeable and discharging copper-plated titanium dioxide nanotube antifouling material as described in claim 7 in marine antifouling, characterized in that, The applications include the use of copper-plated titanium dioxide nanotube antifouling materials, whether uncharged or charge / discharge treated, for antifouling of *Phaeodactylum tricornutum*.

10. The application as described in claim 9, characterized in that, Antifouling material made of copper-plated titanium dioxide nanotubes treated with charge-discharge process is used for antifouling of *Phaeodactylum tricornutum*. TNT-Cu with attached brown finger algae was used as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. The electrode was charged at 0.5–2V for 10–15 min, followed by a discharge treatment for 10–15 min.

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