Cerium oxide / piezoelectric material composite nano-enzyme for antifouling coating as well as preparation method and application of cerium oxide / piezoelectric material composite nano-enzyme

Abstract

The invention discloses cerium oxide / piezoelectric material composite nano-enzyme for an antifouling coating as well as a preparation method and application of the cerium oxide / piezoelectric material composite nano-enzyme, and belongs to the technical field of material chemistry and marine protection. The preparation method of the composite nano-enzyme comprises the following steps: dispersing a metal cerium source and a piezoelectric material source in a solvent according to a mass ratio of 1: (1-5), carrying out phase formation and composite treatment, and collecting a solid product after treatment, thereby obtaining the composite nano-enzyme. The composite nano-enzyme can be used for marine antifouling paint to form a functional material system capable of realizing self-driven antifouling by directly utilizing mechanical energy such as ocean waves, vibration and the like. According to the system, mechanical energy is converted into electrochemical energy to drive in-situ generation of H2O2, and Ce < 3 + > / Ce < 4 + > redox cycle is utilized to efficiently convert H2O2 into ROS, so that sustainable antibacterial and anti-biological adhesion effects are achieved, toxic substances are not released, and the system belongs to an environment-friendly protection technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material chemistry and marine protection technology, and particularly relates to a cerium oxide / piezoelectric material composite nano-enzyme for antifouling coating, a preparation method and application. BACKGROUND

[0002] Marine biofouling is one of the main problems faced by marine engineering facilities during long-term service. There are a large number of bacteria, algae, barnacles and other organisms in the marine environment. These organisms will adhere to the surface of ship hulls, offshore platforms, port facilities and marine monitoring equipment, forming complex multi-species biofilms. Such biofilms not only increase the ship's sailing resistance, energy consumption and maintenance costs, but also accelerate the corrosion of the material surface, shorten the service life of the equipment, and pose a serious threat to the safety and economy of marine engineering. To address this problem, developing efficient, durable and environmentally friendly antifouling materials has become an important research direction in the field of marine engineering.

[0003] Current antifouling strategies mainly rely on traditional antifouling coatings containing organotin, copper or organosilicon compounds. Although these materials can inhibit the adhesion of marine organisms to some extent, they have defects such as high toxicity, serious environmental pollution and rapid decay of protective performance. In recent years, the study of biomimetic catalytic materials has provided a new idea for the field of antifouling, especially nanozymes, which are nanomaterials with natural enzyme-like catalytic activity. Due to their high stability, strong environmental adaptability and scalability, they are widely used in the fields of antibiosis, antifouling and pollution control. Among them, cerium oxide (CeO2) based nanozymes have attracted widespread attention due to their reversible Ce 3+ / Ce 4+ oxidation and reduction cycle characteristics, which can simulate the activity of natural enzymes (such as peroxidase, oxidase and superoxide dismutase) to catalyze the production of reactive oxygen species (ROS) to achieve antibacterial and antifouling functions.

[0004] However, existing cerium oxide-based nanozymes mainly rely on exogenous hydrogen peroxide (H2O2) as a reaction substrate, which faces significant limitations in marine environments. The concentration of H2O2 in natural seawater is extremely low (about 100-250 nM), which is much lower than the required concentration to drive CeO2-based nanozymes to produce ROS. Due to the insufficient supply of H2O2, the reaction efficiency and antifouling performance of CeO2 nanozymes are severely limited in real marine environments. To solve the problem of H2O2 deficiency, some studies have attempted to generate H2O2 in situ using chemical, electrochemical or photocatalytic methods, but these methods often rely on external energy (such as light, electricity or chemical reagents), which is difficult to sustain in environments with insufficient light, turbid seawater or deep sea, making it difficult to achieve long-term self-driven protection.

[0005] The concept of piezocatalysis, proposed in recent years, offers the possibility of constructing a self-driven H2O2 supply system. Piezocatalysis utilizes the polarization charge generated in piezoelectric materials under mechanical stress (such as waves, tides, and vibrations) to achieve interfacial oxygen reduction reactions, thereby driving a series of redox processes. Piezoelectric materials can generate an electric field under mechanical stimulation and induce electron-hole separation, thus continuously generating H2O2 without external energy input. This provides the possibility of constructing a self-driven H2O2 supply system. However, while a single piezoelectric material can generate H2O2 through mechanical stress, its catalytic activity is low, and the generated H2O2 cannot be efficiently converted into biodegradable reactive oxygen species (ROS); moreover, pure CeO2 nanozymes are limited by the insufficient H2O2 concentration in the marine environment. Therefore, how to organically combine these two aspects to form a system capable of self-producing H2O2 under mechanical energy drive and then supplying H2O2 via CeO2... 3+ / Ce 4+ The development of composite nanozyme systems that continuously generate reactive oxygen species has become a key scientific and engineering problem that urgently needs to be solved.

[0006] In summary, existing marine antifouling technologies have the following main shortcomings: (1) Traditional toxic antifouling agents cause serious environmental pollution and have a limited protective lifespan; (2) CeO2 nanozymes depend on exogenous H2O2, which limits their sustained activity in the ocean; (3) Although piezoelectric materials can spontaneously generate H2O2, they lack an efficient ROS catalytic conversion system; (4) There is still a lack of a nanoenzyme system that can utilize the mechanical energy (waves, tides) that is ubiquitous in the marine environment to achieve self-driven antifouling.

[0007] Therefore, there is an urgent need for a composite nanoenzyme material that is structurally stable, energy-sufficient, environmentally friendly, and possesses multi-enzyme mimicry activity to achieve long-term self-driven antibacterial and antifouling protection in marine environments. Summary of the Invention

[0008] Therefore, this invention provides a cerium oxide / piezoelectric material composite nanoenzyme for antifouling coatings, its preparation method, and its application, aiming to realize a long-term antifouling system that can self-generate active oxygen using marine mechanical energy, specifically solving the following technical problems: (1) How to effectively couple piezoelectric materials with CeO2 to construct a self-driven composite nanoenzyme, so that it can continuously generate H2O in situ under the drive of marine mechanical energy (such as waves, tides, ship vibration, etc.). 2， This overcomes the limitation of the scarcity of H2O2 in the natural marine environment; (2) How to ensure that Ce passes 3+ / Ce 4+The redox cycle efficiently converts in-situ generated H2O2 into reactive oxygen species (ROS), thereby enabling CeO2-type nanozymes to be continuously and efficiently produced to achieve antibacterial and antifouling effects. (3) How to achieve the simple and scalable synthesis of the composite nanoenzyme material and to stably integrate it into the organic coating system as a functional filler to ensure the dispersibility, adhesion and long-term antifouling performance of the coating.

[0009] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, a method for preparing cerium oxide / piezoelectric material composite nanozymes for antifouling coatings is provided, comprising the following steps: S1. Disperse the cerium metal source and the piezoelectric material source in a solvent at a mass ratio of 1:(1-5) to form a uniform mixed system; S2. The mixed system in step S1 is subjected to phase formation and composite treatment to obtain cerium oxide (CeO2) / piezoelectric material composite. S3. After treating the cerium oxide (CeO2) / piezoelectric material composite in step S2, collect the solid product to obtain cerium oxide (CeO2) / piezoelectric material composite nanozyme for antifouling coating; The phase formation and composite treatment refers to the process of forming a crystalline phase of cerium oxide (CeO2) and physically or chemically composited with piezoelectric materials, with the aim of forming a tightly bonded composite structure.

[0010] Furthermore, the phase formation and composite treatment is achieved by any of the following methods: (1) Precursor solution method: The phase formation and composite treatment in step S2 includes: drying and evaporating the solvent at 60-90°C, followed by calcination at 400-700°C for 2-5 hours under air or inert gas conditions at a heating rate of 2-10°C / min; Wherein, the cerium source is a cerium salt precursor, the piezoelectric material source is a piezoelectric material precursor, and the inert gas includes, but is not limited to, nitrogen and argon. (2) Heterogeneous recombination method: The phase formation and composite treatment in step S2 includes: drying or heat treatment at 60-700℃ for 0.5-24h; Wherein, the cerium metal source is cerium oxide (CeO2) nanoparticles obtained from cerium metal salt precursor, and the piezoelectric material source is a piezoelectric material obtained from piezoelectric material precursor; The method for collecting the processed product in step S3 is as follows: wash the obtained product alternately with deionized water and organic solvent (such as ethanol) 1-5 times, and dry the washed product at 50-80°C until there is no liquid residue. (3) One-step hydrothermal / solvothermal method: The phase formation and composite treatment described in step S2 includes: performing a hydrothermal or solvothermal reaction at 80-200℃ for 6-24 hours; Wherein, the cerium source is a cerium salt precursor and the piezoelectric material source is a piezoelectric material precursor; The method for collecting the processed product in step S3 is as follows: wash the obtained product alternately with deionized water and organic solvent (such as ethanol) 2-4 times, and then vacuum dry the washed product at 50-70℃ for 8-16 hours.

[0011] Furthermore, in step S1, an auxiliary agent (used to regulate the decomposition rate, particle growth and pore structure of the precursor) is added. The amount of the auxiliary agent added is 0-30 wt.% of the mixed system, and the auxiliary agent includes, but is not limited to, ammonium chloride. The additive is added before dispersion, and the dispersion method is selected from one or more of stirring, ultrasonic dispersion, high-speed homogenization or ball milling, and the dispersion time is 0.5-2h.

[0012] Furthermore, the cerium salt precursor is selected from one or more of cerium nitrate, cerium chloride, cerium acetate, cerium sulfate, or cerium citrate.

[0013] Furthermore, the piezoelectric material precursor is a nitrogen-containing organic precursor or a metal halide salt.

[0014] Furthermore, the nitrogen-containing organic precursor is selected from one or more of urea, melamine, or dicyandiamide.

[0015] Furthermore, the metal halide salt is bismuth halide, which is generated in situ from soluble bismuth salt and halogen salt. The soluble bismuth salt includes, but is not limited to, bismuth nitrate, and the halogen salt includes, but is not limited to, bromide salts (such as KBr), organic bromide salts (such as CTAB), and chloride salts (such as NaCl, KCl, etc.).

[0016] Furthermore, the piezoelectric material is g-C3N4, BiOBr, or BiOCl.

[0017] Furthermore, the solvent mentioned in step S1 is selected from one or more of deionized water or organic solvents (such as ethanol, isopropanol, ethylene glycol, etc.).

[0018] According to a second aspect of the present invention, a cerium oxide (CeO2) / piezoelectric material composite nanozyme prepared by the aforementioned preparation method is provided.

[0019] According to a third aspect of the invention, the application of the cerium oxide (CeO2) / piezoelectric material composite nanoenzyme in marine antifouling coatings is provided.

[0020] According to a fourth aspect of the present invention, a coating is provided, the active ingredient of which contains the cerium oxide (CeO2) / piezoelectric material composite nanoenzyme.

[0021] Furthermore, the method for preparing the coating includes the following steps: Under nitrogen protection, 15-25 mL of organic solvent is added to the reaction flask, the temperature is raised and maintained for reaction; after the reaction is completed, functional monomers, optional silane coupling agents and 0.1 wt.%-2 wt.% of free radical initiators accounting for the total mass of functional monomers are added to the system to carry out polymerization reaction and obtain copolymer solution; The coating is obtained by uniformly dispersing cerium oxide (CeO2) / piezoelectric material composite nanoenzyme, which accounts for 0.01%-10% of the total solid content of the copolymer solution, into the copolymer solution; Furthermore, the coating can be applied to the surface of a substrate and then dried and cured to form a coating layer; the thickness of the coating layer is 5-50 μm.

[0022] Further, the organic solvent is selected from one or more of ethyl acetate or acetone; the free radical initiator is selected from one or more of azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), potassium persulfate (KPS), or ammonium persulfate (APS); the functional monomer is selected from one or more of fluorinated methacrylate monomers (such as perfluorooctyl ethyl methacrylate, dodecafluoroheptyl methacrylate, hexafluorobutyl methacrylate, perfluorooctyl ethyl methacrylate, etc.), short-chain alkyl methacrylate monomers (such as methyl methacrylate, ethyl methacrylate, etc.), or short-chain alkyl acrylate monomers (such as butyl acrylate, ethyl acrylate, etc.), used to improve the hydrophobicity, film-forming properties, and flexibility of the coating; the optional silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane (KH-570), and the amount of γ-methacryloyloxypropyltrimethoxysilane (KH-570) added is 0.1%-1% of the total molar amount of the functional monomers, used to enhance the interfacial bonding force between the composite nanoenzyme and the copolymer solution; The parameters for the heat preservation reaction are: temperature 60-80℃, reaction time 5-30 min; the parameters for the polymerization reaction are: temperature 60-90℃, reaction time 1-4 h; the parameters for the drying are: temperature 20-40℃, drying time 12-24 h; and the parameters for the curing are: temperature 60-80℃, processing time 6-12 h. The coating methods include, but are not limited to, spin coating, scraping coating, and spray coating; the substrates include, but are not limited to, glass, stainless steel, aluminum alloy plates, carbon steel plates, and epoxy resin plates.

[0023] Furthermore, the amount of the free radical initiator added is 1 wt.% of the total mass of the functional monomers; the amount of γ-methacryloyloxypropyltrimethoxysilane added is 0.5% of the total molar mass of the functional monomers; The parameters for the heat preservation reaction are: temperature 70℃, reaction time 20min; the parameters for the polymerization reaction are: temperature 70℃, reaction time 2h.

[0024] Compared with the prior art, the present invention has the following advantages: This invention constructs a functional material system capable of self-driven antifouling by combining environmentally friendly cerium oxide (CeO2) with piezoelectric materials. This system converts mechanical energy into electrochemical energy, driving in-situ H2O2 generation and utilizing CeO2… 3+ / Ce 4+ The redox cycle efficiently converts it into reactive oxygen species (ROS), thereby achieving sustainable antibacterial and anti-bioattachment effects without the release of toxic substances. Its core mechanism is manifested in the following four aspects: (1) Construction of a piezoelectric-enzyme cascade catalytic system: By combining CeO2 with piezoelectric materials, a composite nanoenzyme system with cascade catalytic function is formed. Under the mechanical stress of ocean waves, vibrations, etc., the piezoelectric material generates polarized charges, driving the oxygen reduction reaction to generate H2O2 in situ; the generated H2O2 further reacts with CeO2. 3+ / Ce 4+ Reversible redox cycle coupling efficiently converts it into reactive oxygen species such as hydroxyl radicals (•OH) and HOBr, forming a continuous catalytic reaction chain and significantly improving the generation and conversion efficiency of ROS.

[0025] (2) Development of interface-enhanced synthesis processes: Using processes such as co-precursor solution method, heterogeneous composite method and one-step hydrothermal / solvothermal method, CeO2 and piezoelectric materials can form a dense heterogeneous interface structure. This interface region is rich in oxygen vacancies and has a built-in electric field, which can effectively promote charge separation and transport and inhibit carrier recombination, thereby significantly improving the overall catalytic performance of the material.

[0026] (3) Imparting self-driven dynamic antifouling capability to the coating: Introducing composite nanoenzymes as functional additives into the coating system enables the coating to directly utilize the natural mechanical energy in the marine environment to achieve dynamic and continuous antifouling effect, significantly enhancing its adaptability and reliability in the real marine environment.

[0027] (4) Achieving integrated structure-function synergy: Through the precise design of material structure and interface, the piezoelectric catalytic production of H2O2 and enzyme catalytic conversion of ROS are efficiently coupled, giving the coating long-term, stable and self-driven comprehensive antifouling performance, which can be widely used for long-term protection of facilities such as ships, offshore platforms and marine monitoring equipment. Attached Figure Description

[0028] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0029] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0030] Figure 1 Scanning electron microscope (SEM) images of the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) prepared in Examples 6-8 of this invention; Figure 2 The X-ray diffraction (XRD) spectra of the single nanozyme in Preparation Example 1 (CeO2) and Preparation Example 2 (g-C3N4) of the present invention and the composite nanozyme (CeO2 / g-C3N4-1) in Preparation Example 7 are compared. Figure 3 X-ray diffraction (XRD) spectra of the composite nanozymes in Preparation Example 6 (CeO2 / BiOCl) and Preparation Example 8 (CeO2 / BiOBr-Y) of this invention; Figure 4 The piezoelectric force microscopy (PFM) morphology images of the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) prepared in Examples 6-8 of this invention are shown; wherein, (A) is CeO2 / g-C3N4-1, (B) is CeO2 / BiOBr-Y, and (C) is CeO2 / BiOCl; Figure 5The comparison results of hydrogen peroxide (H2O2) generation under piezoelectric excitation (ultrasound) conditions for the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) prepared in Examples 6-8 of this invention are shown. Two control groups were set up: a group without piezoelectric excitation and a group without composite nanozymes (with an equal amount of H2O replacing the composite nanozymes). Figure 6 The spectroscopic results of the change in activity of the composite nanozyme (CeO2 / g-C3N4-1) halogenated peroxidase (HPO) in Example 7 of this invention over time (0 min, 30 min, 60 min, 90 min, 120 min). Figure 7 The results of the comparative spectra of halogenated peroxidase (HPO) activity in the composite nanozymes of Preparation Example 6 (CeO2 / BiOCl) and Preparation Example 8 (CeO2 / BiOBr-Y) and the blank control group (using an equal amount of H2O instead of composite nanozymes) after ultrasonic treatment for 120 min are shown. Figure 8 The results of the peroxidase-like (POD) activity spectra of the composite nanozyme (CeO2 / g-C3N4-1) prepared in Example 7 and the blank control group (using an equal amount of H2O instead of the composite nanozyme) after ultrasonic treatment for 60 min and standing for 60 min were compared. Figure 9 The images show the spectral results of the peroxidase (POD) activity of the composite nanozyme in Preparation Example 6 (CeO2 / BiOCl) and Preparation Example 8 (CeO2 / BiOBr-Y) of this invention as a function of time (0 min, 15 min, 30 min, 45 min, 60 min); where (A) is CeO2 / BiOBr-Y and (B) is CeO2 / BiOCl. Figure 10 In Example 7 of this invention, the composite nanozyme (CeO2 / g-C3N4-1) was prepared under simulated marine mechanical energy (ultrasonic vibration) to inhibit Escherichia coli (E. coli). E. coli ) and Staphylococcus aureus ( S. aureus Comparison results of antibacterial activity of ) Figure 11 The results show the comparison between the water contact angle and oil contact angle measured at 25°C for the composite nanozyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 of the present invention, the single nanozyme coating in Comparative Example 1 (containing CeO2) and Comparative Example 2 (containing g-C3N4), and the blank control group (coating without any nanozyme). Figure 12The surface energy comparison results are calculated based on contact angle data for the composite nanoenzyme functional coatings (containing CeO2 / BiOBr-Y, CeO2 / BiOCl, CeO2 / BiOBr-F, CeO2 / g-C3N4-1, CeO2 / g-C3N4-2, CeO2 / g-C3N4-3, CeO2 / g-C3N4-4, and CeO2 / g-C3N4-5, respectively) in Examples 1-8 of this invention at 25°C. Figure 13 The results show the comparison of fouling adhesion of the composite nanoenzyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 of the present invention with the single nanoenzyme coatings in Comparative Example 1 (containing CeO2) and Comparative Example 2 (containing g-C3N4) after a marine field hanging plate test lasting up to 180 days. Detailed Implementation

[0031] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] According to a first aspect of the present invention, a method for preparing cerium oxide / piezoelectric material composite nanozymes for antifouling coatings is provided, comprising the following steps: S1. Disperse the cerium metal source and the piezoelectric material source in a solvent at a mass ratio of 1:(1-5) to form a uniform mixed system; S2. The mixed system in step S1 is subjected to phase formation and composite treatment to obtain cerium oxide (CeO2) / piezoelectric material composite. S3. After treating the cerium oxide (CeO2) / piezoelectric material composite in step S2, collect the solid product to obtain cerium oxide (CeO2) / piezoelectric material composite nanozyme for antifouling coating; Phase formation and composite treatment refers to the process of forming a crystalline phase of cerium oxide (CeO2) and physically or chemically combining it with piezoelectric materials, with the aim of forming a tightly bonded composite structure.

[0033] Furthermore, the phase formation and composite treatment is achieved through any of the following methods: (1) Precursor solution method: The phase formation and composite treatment in step S2 includes: drying and evaporating the solvent at 60-90℃, followed by calcination at 400-700℃ for 2-5 hours under air or inert gas conditions at a heating rate of 2-10℃ / min; Among them, the cerium source is a cerium salt precursor, and the piezoelectric material source is a piezoelectric material precursor; (2) Heterogeneous recombination method: The phase formation and composite treatment in step S2 includes drying or heat treatment at 60-700℃ for 0.5-24h; Among them, the cerium source is cerium oxide (CeO2) nanoparticles obtained from the cerium salt precursor, and the piezoelectric material source is the piezoelectric material obtained from the piezoelectric material precursor. The method for collecting the product after processing in step S3 is as follows: wash the obtained product alternately with deionized water and organic solvent (such as ethanol) 1-5 times, and then vacuum dry the washed product at 50-80℃ until there is no liquid residue. (3) One-step hydrothermal / solvothermal method: The phase formation and composite treatment in step S2 includes: hydrothermal or solvothermal reaction at 80-200℃ for 6-24 hours; Among them, the cerium source is a cerium salt precursor, and the piezoelectric material source is a piezoelectric material precursor; The method for collecting the product after processing in step S3 is as follows: wash the obtained product alternately with deionized water and organic solvent (such as ethanol) 2-4 times, and then vacuum dry the washed product at 50-70℃ for 8-16 hours.

[0034] Furthermore, in step S1, an auxiliary agent (used to regulate the decomposition rate, particle growth and pore structure of the precursor) is added. The amount of the auxiliary agent added is 0-30 wt.% of the mixed system. The auxiliary agent includes, but is not limited to, ammonium chloride. The additives are added before dispersion, and the dispersion method is selected from one or more of stirring, ultrasonic dispersion, high-speed homogenization or ball milling, and the dispersion time is 0.5-2h.

[0035] Furthermore, the cerium salt precursor is selected from one or more of cerium nitrate, cerium chloride, cerium acetate, cerium sulfate, or cerium citrate.

[0036] Furthermore, the piezoelectric material precursor is a nitrogen-containing organic precursor or a metal halide salt.

[0037] Furthermore, the nitrogen-containing organic precursor is selected from one or more of urea, melamine, or dicyandiamide.

[0038] Furthermore, the metal halide salt is bismuth halide, which is generated in situ from soluble bismuth salt and halogen salt. Soluble bismuth salt includes, but is not limited to, bismuth nitrate, and halogen salt includes, but is not limited to, bromide salts (such as KBr), organic bromide salts (such as CTAB), and chloride salts (such as NaCl, KCl, etc.).

[0039] Furthermore, the piezoelectric material is g-C3N4, BiOBr, or BiOCl.

[0040] Furthermore, in step S1, the solvent is selected from one or more of deionized water or organic solvents (such as ethanol, isopropanol, ethylene glycol, etc.).

[0041] According to a second aspect of the present invention, a cerium oxide (CeO2) / piezoelectric material composite nanozyme prepared by a preparation method is provided.

[0042] According to a third aspect of the invention, the application of cerium oxide (CeO2) / piezoelectric material composite nanoenzymes in marine antifouling coatings is provided.

[0043] According to a fourth aspect of the present invention, a coating is provided, the active ingredient of which contains cerium oxide (CeO2) / piezoelectric material composite nanoenzyme.

[0044] Furthermore, the method for preparing the coating includes the following steps: Under nitrogen protection, 15-25 mL of organic solvent is added to the reaction flask, the temperature is raised and maintained for reaction; after the reaction is completed, functional monomers, optional silane coupling agents and 0.1 wt.%-2 wt.% of free radical initiators accounting for the total mass of functional monomers are added to the system to carry out polymerization reaction and obtain copolymer solution; A cerium oxide (CeO2) / piezoelectric material composite nanoenzyme, accounting for 0.01%-10% of the total solid content of the copolymer solution, is uniformly dispersed in the above copolymer solution to obtain a coating. Coatings can be applied to the surface of a substrate and then dried and cured to form a coating. The coating thickness is 5-50μm.

[0045] Further, the organic solvent is selected from one or more of ethyl acetate or acetone; the free radical initiator is selected from one or more of azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), potassium persulfate (KPS), or ammonium persulfate (APS); the functional monomer is selected from one or more of fluorinated methacrylate monomers (such as perfluoroalkyl methacrylates, partially fluorinated alkyl methacrylates, etc.), short-chain alkyl methacrylate monomers (such as methyl methacrylate, ethyl methacrylate, etc.) or short-chain alkyl acrylate monomers (such as butyl acrylate, ethyl acrylate, etc.), used to improve the hydrophobicity, film-forming properties, and flexibility of the coating; the optional silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane (KH-570), the amount of γ-methacryloyloxypropyltrimethoxysilane (KH-570) added is 0.1%-1% of the total molar amount of the functional monomers, used to enhance the interfacial bonding force between the composite nanoenzyme and the copolymer solution; The parameters for the heat preservation reaction are: temperature 60-80℃, reaction time 5-30 min; the parameters for the polymerization reaction are: temperature 60-90℃, reaction time 1-4 h; the uniform dispersion method is selected from one or more of stirring, ultrasonic dispersion, high-speed homogenization or ball milling, and the uniform dispersion time is 0.5-2 h; the drying parameters are: temperature 20-40℃, drying time 12-24 h; the curing parameters are: temperature 60-80℃, treatment time 6-12 h. Coating methods include, but are not limited to, spin coating, scraping coating, and spray coating; substrates include, but are not limited to, glass, stainless steel, aluminum alloy plates, carbon steel plates, and epoxy resin plates.

[0046] Furthermore, the amount of free radical initiator added is 1 wt.% of the total mass of the functional monomers; the amount of γ-methacryloyloxypropyltrimethoxysilane added is 0.5% of the total molar mass of the functional monomers. The parameters for the heat preservation reaction are: temperature 70℃, reaction time 20min; the parameters for the polymerization reaction are: temperature 70℃, reaction time 2h.

[0047] Preparation Example 1 Preparation of CeO2 nanozymes 5.45 g of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) was dissolved in 50 mL of 80% ethanol-water mixed solution and stirred in an oil bath at 50 °C until a transparent and homogeneous solution was formed. Under continuous stirring, 12 mL of 3M ammonia water (NH4OH) was slowly added to form a yellow suspension, and the reaction was continued to be stirred in an oil bath at 50 °C for 24 h. After the reaction was completed, the precipitate was collected by centrifugation and washed three times each with ethanol and deionized water. The washed product was dried at 80 °C for 24 h. It was then transferred to a muffle furnace and heated to 500 °C at a rate of 1 °C / min and held at this temperature for 1 h to obtain a light yellow powdery CeO2 nanozyme, denoted as CeO2.

[0048] Preparation Example 2 Preparation of g-C3N4 nanozymes 5g of urea was weighed and placed in a crucible. The temperature was increased to 550℃ at 5℃ / min and held for 3h in an air atmosphere to obtain the calcined product. The product was then naturally cooled to room temperature and homogenized by grinding to obtain powdered g-C3N4 nanozyme, denoted as g-C3N4.

[0049] Preparation Example 3 Preparation of BiOBr nanozymes Weigh 4 mmol Bi(NO3)3·5H2O and dissolve it in 30 mL of ethylene glycol. Stir for 10 min to form solution A. Dissolve 4 mmol CTAB and 20 mg PVP in 30 mL of ethylene glycol and stir until homogeneous to form solution B. Slowly add solution A to solution B at a rate of 2 mL / min and continue stirring for 60 min to obtain a mixed solution. Transfer the mixed solution to a 100 mL polytetrafluoroethylene-lined reactor and solvothermal react at 160 °C for 12 h. After the reaction is complete, allow it to cool naturally to room temperature. Collect the precipitate and wash it three times alternately with deionized water and ethanol. Dry the washed product at 60 °C until no liquid residue remains to obtain BiOBr nanozyme, denoted as BiOBr.

[0050] Preparation Example 4 Preparation of BiOCl nanozymes 1.5 mmol Bi(NO3)3·5H2O was dissolved in 40 mL of ethylene glycol, followed by the addition of 50 mg PVP and stirring to dissolve. Then, 1.55 mmol KCl was added and the mixture was stirred for 10 minutes. The mixture was then transferred to a 100 mL polytetrafluoroethylene-lined reactor and heated at 160 °C for 12 h. After natural cooling, the precipitate was collected and washed three times with deionized water and ethanol. The washed product was dried at 60 °C until no liquid residue remained, yielding BiOCl nanozyme, denoted as BiOCl.

[0051] Preparation Example 5 Preparation of CeO2 / BiOBr composite nanozymes Weigh 0.172 g of CeO2 from Preparation Example 1 and add it to 16 mL of isopropanol dispersion containing 0.86 g of BiOBr from Preparation Example 3. Stir at 60 °C for 12 h to obtain a mixture. After the reaction is complete, allow it to cool naturally to room temperature. Collect the precipitate and wash it three times alternately with deionized water and ethanol. Transfer the washed product to a vacuum drying oven at 60 °C and dry for 12 h to obtain CeO2 / BiOBr composite nanozyme, denoted as CeO2 / BiOBr-F.

[0052] Preparation Example 6 Preparation of CeO2 / BiOCl composite nanozymes 1.5 mmol Bi(NO3)3·5H2O and 1.5 mmol KCl were dissolved in 40 mL of ethylene glycol and ultrasonically dispersed for 20 min. Then, 0.1 g of CeO2 from Preparation Example 1 was added and ultrasonically dispersed for 30 min to ensure thorough mixing. The mixture was transferred to a 100 mL polytetrafluoroethylene-lined reactor and heated at 160 °C for 12 h. After natural cooling, the precipitate was collected by centrifugation and washed three times alternately with deionized water and ethanol. The washed product was transferred to a vacuum drying oven at 60 °C and dried for 12 h to obtain CeO2 / BiOCl composite nanozyme, denoted as CeO2 / BiOCl.

[0053] Preparation Example 7 Preparation of CeO2 / g-C3N4 composite nanozymes Weigh 2.17g Ce(NO3)3·6H2O and dissolve it in 20mL of deionized water. Stir until a clear solution is obtained. Add 4.5g urea, continue stirring for 30min and ultrasonically disperse for 20min to ensure the system is homogeneous and form a mixture. Place the mixture in a water bath at 80℃ to evaporate the deionized water and form a white precursor solid. Place the white precursor solid in a crucible and heat it to 550℃ at 5℃ / min under a nitrogen atmosphere and keep it at that temperature for 3h to form a CeO2 / g-C3N4 complex. Cool it naturally to room temperature and homogenize it by grinding to obtain a light yellow powdery CeO2 / g-C3N4 composite nanozyme, denoted as CeO2 / g-C3N4-1.

[0054] Preparation Example 8 Preparation of CeO2 / BiOBr composite nanozymes Weigh 4 mmol Bi(NO3)3·5H2O and 0.8 mmol Ce(NO3)3·6H2O and dissolve them in 30 mL of ethylene glycol. Stir for 10 min to form solution A. Dissolve 4 mmol CTAB and 20 mg PVP in 30 mL of ethylene glycol and stir until homogeneous to form solution B. Slowly add solution A to solution B at a rate of 2 mL / min and continue stirring for 60 min to obtain a mixed solution. Transfer the mixed solution to a 100 mL polytetrafluoroethylene-lined reactor and solvothermal react at 160 °C for 12 h to form CeO2 / BiOBr composite. After the reaction, wash the product three times alternately with deionized water and ethanol. Transfer the washed product to a vacuum drying oven at 60 °C and dry for 12 h to obtain CeO2 / BiOBr composite nanozyme, denoted as CeO2 / BiOBr-Y.

[0055] Preparation Example 9 Preparation of CeO2 / g-C3N4 composite nanozymes 2.17 g of Ce(NO3)3·6H2O was weighed and dissolved in 20 mL of deionized water. The solution was stirred until homogeneous to obtain a clear solution. 6 g of melamine was added and the mixture was magnetically stirred for 40 min to ensure homogeneity and form a mixture. The mixture was heated in a water bath at 85 °C to evaporate the deionized water and form a white precursor solid. The white precursor solid was placed in a crucible and heated to 600 °C at 4 °C / min under air atmosphere and kept at that temperature for 4 h to form a CeO2 / g-C3N4 complex. The complex was naturally cooled to room temperature and homogenized by grinding to obtain a yellow powdery CeO2 / g-C3N4 composite nanozyme, denoted as CeO2 / g-C3N4-2.

[0056] Preparation Example 10 Preparation of CeO2 / g-C3N4 composite nanozymes 2.17 g of Ce(NO3)3·6H2O was weighed and dissolved in 20 mL of deionized water. The solution was stirred until homogeneous to obtain a clear solution. 6 g of urea and 3 g of melamine were added, along with 0.5 g of ammonium chloride. The mixture was sonicated for 30 min and stirred for 30 min to ensure homogeneity, forming a mixture. The mixture was heated in a water bath at 80 °C to evaporate the deionized water, forming a white precursor solid. The white precursor solid was placed in a crucible and heated to 550 °C at 5 °C / min under an argon atmosphere and held for 3 h to form a CeO2 / g-C3N4 complex. The complex was naturally cooled to room temperature and homogenized by grinding to obtain a light yellow powdery CeO2 / g-C3N4 composite nanozyme, denoted as CeO2 / g-C3N4-3.

[0057] Preparation Example 11 Preparation of CeO2 / g-C3N4 composite nanozymes 2.17 g of Ce(NO3)3·6H2O was weighed and dissolved in 20 mL of deionized water. The solution was stirred until homogeneous and a clear solution was obtained. 2.5 g of urea and 2 g of dicyandiamide were added and stirred for 30 min to ensure the system was homogeneous and a mixture was formed. The mixture was heated in a water bath at 80 °C to evaporate the deionized water and a white precursor solid was formed. The white precursor solid was placed in a crucible and heated to 600 °C at 5 °C / min under a nitrogen atmosphere and held for 4 h to form a CeO2 / g-C3N4 complex. The complex was cooled to room temperature and homogenized by grinding to obtain a light yellow powdery CeO2 / g-C3N4 composite nanozyme with uniform crystals and a dense structure, which was designated CeO2 / g-C3N4-4.

[0058] Preparation Example 12 Preparation of CeO2 / g-C3N4 composite nanozymes Weigh 2.17g Ce(NO3)3·6H2O and dissolve it in 20mL of deionized water. Stir until a clear solution is obtained. Add 2.5g urea, 1.5g melamine and 1g dicyandiamide, continue stirring for 30min and ultrasonically disperse for 40min to ensure the system is homogeneous and form a mixture. Place the mixture in a water bath at 85℃ to evaporate the deionized water and form a white precursor solid. Place the white precursor solid in a crucible and heat it to 550℃ at 5℃ / min under a nitrogen atmosphere and keep it at that temperature for 3h to form a CeO2 / g-C3N4 complex. Cool it naturally to room temperature and homogenize it by grinding to obtain a light yellow powdery CeO2 / g-C3N4 composite nanozyme with good crystallinity and dispersibility, denoted as CeO2 / g-C3N4-5.

[0059] Example 1 A method for preparing a CeO2 / BiOBr composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.02 mol of perfluorooctyl ethyl methacrylate, 0.02 mol of methyl methacrylate, and 0.02 mol of butyl acrylate were added to the system, along with 0.005 mol of KH-570. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0060] (2) Preparation of CeO2 / BiOBr composite nanoenzyme functional coating CeO2 / BiOBr-Y, accounting for 5 wt.% of its solid content, was added to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 1 h, CeO2 / BiOBr-Y composite nanoenzyme functional coating was obtained.

[0061] The CeO2 / BiOBr-Y composite nanoenzyme functional coating was spin-coated onto the surface of a glass substrate, dried at 25°C for 12 hours, and then cured at 70°C for 8 hours to obtain a CeO2 / BiOBr-Y composite nanoenzyme functional coating with a thickness of about 30 μm. The coating is dense and uniform.

[0062] Example 2 A method for preparing a CeO2 / BiOCl composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.02 mol of perfluorooctyl ethyl methacrylate, 0.02 mol of methyl methacrylate, and 0.02 mol of butyl acrylate were added to the system, along with 0.005 mol of KH-570. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0063] (2) Preparation of CeO2 / BiOCl composite nanoenzyme functional coating CeO2 / BiOCl, accounting for 5 wt.% of the solid content of the transparent acrylic copolymer solution in step (1), was added to the solution of Preparation Example 6. After stirring and ultrasonic dispersion for 1 h, CeO2 / BiOCl composite nanoenzyme functional coating was obtained.

[0064] The CeO2 / BiOCl composite nanoenzyme functional coating was spin-coated onto the surface of a glass substrate, dried at 25°C for 12 hours, and then cured at 70°C for 8 hours to obtain a CeO2 / BiOCl composite nanoenzyme functional coating with a thickness of about 30 μm. The coating is dense and uniform.

[0065] Example 3 A method for preparing a CeO2 / BiOBr composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.02 mol of perfluorooctyl ethyl methacrylate, 0.02 mol of methyl methacrylate, and 0.02 mol of butyl acrylate were added to the system, along with 0.005 mol of KH-570. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0066] (2) Preparation of CeO2 / BiOBr composite nanoenzyme functional coating CeO2 / BiOBr-F, accounting for 5 wt.% of its solid content, was added to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 1 h, CeO2 / BiOBr-F composite nanoenzyme functional coating was obtained.

[0067] The CeO2 / BiOBr-F composite nanoenzyme functional coating was spin-coated onto the surface of a glass substrate, dried at 25°C for 12 hours, and then cured at 70°C for 8 hours to obtain a CeO2 / BiOBr-F composite nanoenzyme functional coating with a thickness of about 30 μm. The coating is dense and uniform.

[0068] Example 4 A method for preparing a CeO2 / g-C3N4 composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.02 mol of perfluorooctyl ethyl methacrylate, 0.02 mol of methyl methacrylate, and 0.02 mol of butyl acrylate were added to the system, along with 0.005 mol of KH-570. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0069] (2) Preparation of CeO2 / g-C3N4 composite nanoenzyme functional coating CeO2 / g-C3N4-1, accounting for 5 wt.% of its solid content, was added to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 1 h, CeO2 / g-C3N4-1 composite nanoenzyme functional coating was obtained.

[0070] The CeO2 / g-C3N4-1 composite nanoenzyme functional coating was spin-coated onto the surface of a glass substrate, dried at 25°C for 12 hours, and then cured at 70°C for 8 hours to obtain a CeO2 / g-C3N4-1 composite nanoenzyme functional coating with a thickness of about 30 μm. The coating is dense and uniform.

[0071] Example 5 A method for preparing a CeO2 / g-C3N4 composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:2, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.015 mol of dodecafluoroheptyl methacrylate, 0.015 mol of ethyl methacrylate, and 0.01 mol of butyl acrylate were added to the system. 1 wt.% of BPO (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 65 °C for 3 h to obtain a transparent acrylic copolymer solution.

[0072] (2) Preparation of CeO2 / g-C3N4 composite nanoenzyme functional coating CeO2 / g-C3N4-2, accounting for 3 wt.% of its solid content, was added to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 1.5 h, CeO2 / g-C3N4-2 composite nanoenzyme functional coating was obtained.

[0073] The CeO2 / g-C3N4-2 composite nanoenzyme functional coating was applied to the surface of a stainless steel substrate by a scraping method, dried at 30°C for 18 hours, and then cured at 60°C for 8 hours to obtain a CeO2 / g-C3N4-2 composite nanoenzyme functional coating with a thickness of about 30 μm. The coating has a smooth surface and good adhesion.

[0074] Example 6 A method for preparing a CeO2 / g-C3N4 composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.02 mol of methyl methacrylate and 0.02 mol of butyl acrylate were added to the system. 1 wt.% of AIBN was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0075] (2) Preparation of CeO2 / g-C3N4 composite nanoenzyme functional coating Add 1 wt.% of the CeO2 / g-C3N4-3 composite nanozyme from Preparation Example 10 to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 40 min, CeO2 / g-C3N4-3 composite nanozyme functional coating is obtained.

[0076] The CeO2 / g-C3N4-3 composite nanoenzyme functional coating was sprayed onto the surface of an aluminum alloy substrate, dried at room temperature for 12 hours, and then cured at 70°C for 6 hours to obtain a CeO2 / g-C3N4-3 composite nanoenzyme functional coating with a thickness of about 25 μm.

[0077] Example 7 A method for preparing a CeO2 / g-C3N4 composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 25 mL of ethyl acetate was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was kept at 70 °C for 20 min to remove oxygen. 0.025 mol of hexafluorobutyl methacrylate, 0.015 mol of methyl methacrylate, and 0.01 mol of butyl acrylate were added to the system, along with 0.003 mol of KH-570. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was kept at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0078] (2) Preparation of CeO2 / g-C3N4 composite nanoenzyme functional coating Add 5 wt.% of the CeO2 / g-C3N4-4 composite nanozyme from Preparation Example 11 to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 1 h, CeO2 / g-C3N4-4 composite nanozyme functional coating is obtained.

[0079] The CeO2 / g-C3N4-4 composite nanoenzyme functional coating was spin-coated onto the surface of a carbon steel plate substrate, dried at 30°C for 16 hours, and then cured at 80°C for 8 hours to obtain a CeO2 / g-C3N4-4 composite nanoenzyme functional coating with a thickness of about 30 μm and a smooth and hydrophobic surface.

[0080] Example 8 A method for preparing a CeO2 / g-C3N4 composite nanoenzyme functional coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.015 mol of perfluorooctyl ethyl acrylate, 0.015 mol of ethyl methacrylate, and 0.015 mol of butyl acrylate were added to the system. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0081] (2) Preparation of CeO2 / g-C3N4 composite nanoenzyme functional coating Add 0.5 wt.% of the CeO2 / g-C3N4-5 composite nanozyme from Preparation Example 12 to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 1 h, a CeO2 / g-C3N4-5 composite nanozyme functional coating is obtained.

[0082] The CeO2 / g-C3N4-5 composite nanoenzyme functional coating was sprayed onto the surface of an epoxy resin board, dried at 25°C for 24 hours, and then cured at 70°C for 12 hours to obtain a CeO2 / g-C3N4-5 composite nanoenzyme functional coating with a thickness of about 30 μm. The coating surface is smooth, dense, and has a low load.

[0083] Comparative Example 1 A method for preparing a CeO2 nanoenzyme coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.015 mol of perfluorooctyl ethyl methacrylate, 0.015 mol of methyl methacrylate, and 0.01 mol of butyl acrylate were added to the system, along with 0.005 mol of KH-570. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0084] (2) Preparation of CeO2 nanoenzyme coating Add 5 wt.% of the CeO2 nanozyme from Preparation Example 1 to the transparent acrylic copolymer solution in step (1), and after stirring and ultrasonic dispersion for 1 h, obtain CeO2 nanozyme coating.

[0085] The CeO2 nanoenzyme coating was spin-coated onto the surface of an epoxy resin board, dried at 25°C for 12 hours, and then cured at 70°C for 8 hours to obtain the CeO2 nanoenzyme coating.

[0086] Comparative Example 2 A method for preparing g-C3N4 nanoenzyme coating includes the following steps: (1) Preparation of copolymer solution Under nitrogen purging, 20 mL of a mixed organic solvent of ethyl acetate and acetone (1:1, v / v) was added to a 100 mL reaction flask equipped with a stirrer, and the mixture was reacted at 70 °C for 20 min to remove oxygen. 0.015 mol of perfluorooctyl ethyl methacrylate, 0.015 mol of methyl methacrylate, and 0.01 mol of butyl acrylate were added to the system, along with 0.005 mol of KH-570. 1 wt.% of AIBN (based on the total mass of the three functional monomers) was added, and the mixture was reacted at 70 °C for 2 h to obtain a transparent acrylic copolymer solution.

[0087] (2) Preparation of g-C3N4 nanoenzyme coating Add 5 wt.% of the g-C3N4 nanozyme from Preparation Example 2 to the transparent acrylic copolymer solution in step (1). After stirring and ultrasonic dispersion for 1 h, the g-C3N4 nanozyme coating is obtained.

[0088] The above g-C3N4 nanoenzyme coating was spin-coated onto the surface of an epoxy resin board, dried at 25°C for 12 hours, and then cured at 70°C for 8 hours to obtain the g-C3N4 nanoenzyme coating.

[0089] Test Example 1 To systematically evaluate the structure, morphology, and key physical properties of the composite nanozyme of this invention, the following characterization and analysis were performed: (1) The morphology and microstructure of the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) in Preparation Examples 6-8 were observed by scanning electron microscopy (SEM).

[0090] (2) X-ray diffraction (XRD) was used to analyze the crystal structure of the single nanozymes in Preparation Example 1 (CeO2) and Preparation Example 2 (g-C3N4) and the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) in Preparation Examples 6-8.

[0091] (3) The piezoelectric properties of the composite nanozyme CeO2 / g-C3N4-1 in Preparation Example 7 were tested using piezoelectric response force microscopy (PFM).

[0092] Relevant characterization results are as follows Figures 1-4 As shown: Figure 1 The SEM images show that: (1) CeO2 / BiOCl (Preparation Example 6) and CeO2 / BiOBr-Y (Preparation Example 8) exhibit a three-dimensional flower-like microsphere structure, which is assembled from intercalated nanosheets. The nanosheets are uniformly loaded with high-density, small-sized CeO2 nanoparticles. This hierarchical structure has abundant interfaces and active sites, which is beneficial to the catalytic reaction. (2) CeO2 / g-C3N4-1 (Preparation Example 7) exhibits a typical heterogeneous composite morphology. CeO2 nanoparticles with a particle size of 5-10 nm are uniformly attached to the surface of g-C3N4, and the two form a uniform composite interface, which is beneficial to improve the specific surface area and interfacial contact area of ​​the material, thereby providing more active sites for subsequent catalytic reactions.

[0093] Figure 2 and 3The XRD patterns in the samples show that the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, and CeO2 / BiOBr-Y) prepared in Examples 6-8 all exhibit characteristic diffraction peaks of both CeO2 and the corresponding piezoelectric materials (BiOBr, BiOCl, and g-C3N4-1, respectively). It is noteworthy that (e.g.) Figure 2 As shown in the figure, compared with the single nanozymes in Preparation Example 1 (CeO2) and Preparation Example 2 (g-C3N4), the diffraction peak intensity of the composite nanozyme (CeO2 / g-C3N4-1) in Preparation Example 7 was relatively weakened and the half-width of the peak increased, which further confirms that CeO2 nanoparticles were successfully loaded on the surface of the piezoelectric material and formed a heterojunction structure.

[0094] Figure 4 The PFM morphology diagrams show that the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) in Preparation Examples 6-8 all exhibit obvious piezoelectric response phase reversal characteristics. Their piezoelectric phase diagrams show a typical 180° reversal ring, indicating that the composite nanozymes have reversible polarization characteristics and stable piezoelectric activity.

[0095] The above results demonstrate that the composite nanozyme of the present invention possesses a nanoscale heterogeneous interface structure with tight interfacial bonding and abundant surface pores. This structure effectively promotes electron transfer between interfaces and provides abundant highly active reaction sites, thus laying the structural foundation for the material to achieve efficient piezoelectric catalytic reactions and enhanced enzyme-like activity.

[0096] Test Example 2 To evaluate the catalytic performance of the composite nanozymes of this invention under mechanical energy-driven conditions, the peroxidase-like (POD) and halogen peroxidase-like (HPO) activities of the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) prepared in Examples 6-8 were systematically tested under piezoelectric excitation conditions to systematically examine their reactive oxygen species (ROS) generation and conversion capabilities. All experiments were conducted at room temperature and under complete darkness. Control groups were set up: a group without piezoelectric excitation and a group without composite nanozymes (using an equal amount of H2O instead of composite nanozymes). The specific test methods are as follows: Nanozymes were dispersed in deionized water at a concentration of 1 mg / mL, and their piezoelectric effect was stimulated by simulating environmental mechanical energy (such as ocean waves and tides) through ultrasonic treatment. The content of hydrogen peroxide (H₂O₂) generated during the reaction was quantitatively detected using the KI-potassium phthalate colorimetric method. The POD-like and HPO-like catalytic activities of the nanozymes under ultrasonic conditions were evaluated using 3,3',5,5'-tetramethylbenzidine (TMB) and phenol red (PR) as chromogenic substrates, respectively. The experimental results are as follows: Figures 5-9 As shown: Figure 5The comparison of H2O2 generation showed that the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, and CeO2 / BiOBr-Y) in Preparation Examples 6-8 all exhibited significant piezoelectric catalytic activity under ultrasonic vibration conditions, continuously generating H2O2. In contrast, no significant H2O2 generation was detected in the non-piezoelectric group and the group without composite nanozymes. Furthermore, the H2O2 production of these three composite nanozymes accumulated significantly with increasing reaction time, indicating their ability to continuously catalyze H2O2 production under ultrasonic excitation. Notably, CeO2 / g-C3N4-1 showed the highest H2O2 generation efficiency among the three composite nanozymes, with its cumulative production significantly exceeding that of CeO2 / BiOCl and CeO2 / BiOBr-Y, suggesting that this composite material possesses superior piezoelectric catalytic activity and interfacial charge separation efficiency.

[0097] In halogen-like peroxidase (HPO-like) activity assays (e.g.) Figure 6 and 7 As shown in the preparation examples 6-8, the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) all exhibited typical halogen peroxidase activity characteristics under ultrasonic treatment: the PR characteristic absorption peak decreased at about 434 nm, while the absorbance increased significantly at about 590 nm. Figure 6 Further, it was shown that the intensity of the PR characteristic absorption peak at approximately 590 nm in CeO2 / g-C3N4-1 (Preparation Example 7) increased significantly in a time-dependent manner as the ultrasonic treatment time increased from 0 min to 120 min. These results collectively confirm that all three composite nanozymes can utilize mechanical energy to drive halogen-peroxidase-like activity, exhibiting significant HPO-like activity. In peroxidase-like (POD-like) activity assays (such as...) Figure 8 and 9 As shown in the preparation examples 6-8, the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) all exhibited typical catalytic oxidation characteristics under ultrasonic treatment: the TMB characteristic absorption peak appeared and was enhanced at about 652 nm. Figure 9 Further analysis shows that the intensity of the TMB characteristic absorption peak at approximately 652 nm in CeO2 / BiOCl (Preparation Example 6) and CeO2 / BiOBr-Y (Preparation Example 8) increases significantly in a time-dependent manner as the ultrasonic treatment time increases from 0 min to 60 min. These results collectively confirm that all three composite nanozymes can effectively catalyze the oxidation of TMB under mechanical energy excitation, exhibiting significant POD-like activity.

[0098] Notably, CeO2 / g-C3N4-1 (Preparation Example 7) exhibited significantly higher activity in both types of catalytic reactions compared to the static conditions and the control groups, demonstrating excellent piezoelectric catalytic enhancement performance. This further confirms that the catalytic function of the composite nanozyme of this invention can be effectively triggered and regulated through the piezoelectric effect.

[0099] The above results demonstrate that, under mechanical vibration, the composite nanozyme of this invention can generate H2O2 in situ through the piezoelectric effect. The generated H2O2 further diffuses onto the material surface via Ce... 3+ / Ce 4+ The redox cycle and enzyme-like active sites are efficiently converted into reactive oxygen species such as hydroxyl radicals (•OH) and HOBr. This process constitutes a cascade catalytic mechanism from piezoelectric H2O2 production to enzymatic conversion of ROS, and the synergistic effect of the two significantly enhances the generation capacity of reactive oxygen species and the catalytic reaction kinetics of the entire system.

[0100] Test Example 3 To evaluate the antibacterial properties of composite nanozymes under mechanical energy-driven conditions, *Escherichia coli* (E. coli) was used as an example. E. coli ) and Staphylococcus aureus ( S. aureus Using model bacteria, the antibacterial activity of the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) prepared in Examples 6-8 was investigated under simulated marine mechanical energy (ultrasonic vibration) conditions. By systematically comparing the antibacterial effects with and without ultrasonic treatment, the cascade synergistic effect between the piezoelectric effect excited by ultrasound and the catalytic activity of the nanozymes was clarified, thus confirming the significant improvement of the antibacterial performance of the materials by this effect. The specific methods are as follows: Nanozyme (200 μg·mL) -1 ), Br - (5mM) and H2O2 (250nM, designed to simulate extremely low background concentrations in natural seawater) were added to a solution containing 1×10 6 CFU·mL -1 E. coli or S. aureus In a fresh suspension, mix thoroughly to form a complete reaction system. Divide the reaction system into two groups for further treatment: Ultrasonic treatment group: Placed in an ultrasonic cleaner, ultrasonically treated for 120 minutes at 40kHz and 240W to simulate marine mechanical energy such as ocean waves and tides. The entire treatment process was carried out under constant temperature and light-proof conditions at 37℃. Non-ultrasonic treatment group: placed at the same temperature and in the dark for 60 minutes without ultrasonic treatment; A blank control group was also set up, i.e., no composite nanozyme was added (containing only Br). - (and H2O2), and were also divided into two groups: ultrasonically treated and non-ultrasonic treated, with all other conditions kept the same; After processing, each group of samples was serially diluted (usually to 10⁻⁶). 3 -10 6 (CFU / mL), 100 μL of the diluted solution was spread onto LB solid medium and incubated at 37°C for 20 h. The colony count was recorded. The experimental results are as follows: Figure 10 As shown in Table 1, where, Figure 10 The antibacterial effect of the composite nanozyme (CeO2 / g-C3N4-1) prepared in Example 7 was demonstrated: Table 1 below shows the effects of the composite nanozymes (CeO2 / BiOCl, CeO2 / g-C3N4-1, CeO2 / BiOBr-Y) prepared in Examples 6-8 on [the following information is missing from the original text]. E. coli and S. aureus Antibacterial rate results for the two strains:

[0101] As can be seen from the data in Table 1 above: Regarding... E. coli and S. aureus In the antibacterial tests, all three composite nanozyme coatings in Preparation Examples 6-8 exhibited excellent antibacterial activity, with antibacterial rates all exceeding 95%. Specifically, in Preparation Example 6, the CeO2 / BiOCl antibacterial rate against both strains was higher than 95.12%; in Preparation Example 7, the CeO2 / g-C3N4-1 antibacterial rate against both strains reached 99.99%, demonstrating the best antibacterial performance; and in Preparation Example 8, the CeO2 / BiOBr-Y antibacterial rate against both strains was higher than 98.76%.

[0102] also, Figure 10 The comparison results of antibacterial activity shown further confirm that, in the presence of Br - Under H2O2 conditions, CeO2 / g-C3N4-1 (in Preparation Example 7) for E. coli and S. aureus All samples exhibited significant antibacterial activity, with the ultrasonic-treated group showing a significantly better antibacterial effect than the non-ultrasonic-treated group. This indicates that the mechanical energy simulated by ultrasound can effectively excite the piezoelectric effect of the composite material, improving its efficiency in catalytically generating reactive oxygen species (ROS), thereby enhancing its bactericidal ability.

[0103] The above results demonstrate that the composite nanozyme of the present invention can achieve stable and efficient in-situ antibacterial function under simulated marine mechanical energy conditions.

[0104] Test Example 4 To evaluate the surface wettability and antifouling properties of the composite nanoenzyme functional coatings of this invention, a contact angle meter (Theta Lite, Sweden) was used at 25°C to test the wettability of the composite nanoenzyme functional coatings (containing CeO2 / BiOBr-Y, CeO2 / BiOCl, CeO2 / BiOBr-F, CeO2 / g-C3N4-1, CeO2 / g-C3N4-2, CeO2 / g-C3N4-3, CeO2 / g-C3N4-4, and CeO2 / g-C3N4-5, respectively) in Examples 1-8, as well as the single nanoenzyme coatings in Comparative Example 1 (containing CeO2) and Comparative Example 2 (containing g-C3N4). Deionized water was used as the liquid medium for the test, and the water droplet volume was set to 2µL. The contact angle change was continuously recorded for 10 seconds from the moment the water droplet came into contact with the coating, and the average contact angle was calculated using data within the range of 7-10 seconds. At the same time, a blank control group (coating without any nanozymes) was set up: the preparation of this group only included step (1) in Example 4, that is, the prepared transparent acrylic copolymer solution was directly used to form a film under the same curing parameters (spin-coated onto the surface of a glass substrate, dried at 25°C for 12 hours, and cured at 70°C for 8 hours). The resulting coating was a pure resin coating without any nanozymes.

[0105] The test results are as follows Figure 11 and 12 As shown: Depend on Figure 11 It can be seen that the composite nanoenzyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 has a water contact angle of approximately 120°, an oil contact angle of approximately 100°, and a surface energy of less than 15 mJ·m. 2 Its wettability data are comparable to those of the single nanoenzyme coatings in Comparative Example 1 (containing CeO2) and Comparative Example 2 (containing g-C3N4). This indicates that after CeO2 is combined with piezoelectric materials (such as g-C3N4), the inherent low surface energy characteristics of the coating matrix are maintained, while also possessing excellent hydrophobic and oleophobic properties.

[0106] In addition, such as Figure 12 The surface energy results of the composite nanozyme functional coatings (containing CeO2 / BiOBr-Y, CeO2 / BiOCl, CeO2 / BiOBr-F, CeO2 / g-C3N4-1, CeO2 / g-C3N4-2, CeO2 / g-C3N4-3, CeO2 / g-C3N4-4, and CeO2 / g-C3N4-5, respectively) in Examples 1-8 show that the surface energies of these eight composite nanozyme functional coatings are all maintained at a low level (mostly between 10-25 mJ·m). 2 (range), where the surface energy of the composite nanoenzyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 is less than 15 mJ·m.2 The results are consistent with those of the wettability test.

[0107] The formation mechanism of the hydrophobic and oleophobic properties of the aforementioned composite nanozymes lies in the uniform dispersion of composite nanozymes (such as CeO2 / BiOBr-Y, CeO2 / BiOCl, CeO2 / BiOBr-F, and CeO2 / g-C3N4) in the matrix, constructing a low-energy interface structure at the micro-nano scale. This structure, while maintaining stable mechanical properties, primarily achieves two functions: firstly, it imparts excellent water drainage and antifouling properties to the surface; secondly, it effectively reduces the interfacial adhesion of microorganisms and organic pollutants, thereby inhibiting biofouling. This lays the foundation for the coating to achieve long-term cleaning and protection in marine environments.

[0108] Test Example 5 Based on the surface wettability and antifouling performance test results of the composite nanoenzyme functional coating in Test Example 4, a 180-day marine field hanging plate test was conducted in the Bohai Sea (117°46′E, 39°43′N) in Tianjin, China, to verify the long-term antifouling performance of the composite nanoenzyme functional coating of the present invention. The test samples included: samples coated with the composite nanoenzyme functional coatings of Example 1 (containing CeO2 / BiOBr-Y), Example 2 (containing CeO2 / BiOCl), and Example 4 (containing CeO2 / g-C3N4-1); samples coated with the single nanoenzyme coatings of Comparative Example 1 (containing CeO2) and Comparative Example 2 (containing g-C3N4); and a blank control sample. All the above samples were fixed on chains and vertically immersed to a depth of 0.5 m below sea level.

[0109] After soaking, the chain was removed, and the sample surface was gently rinsed with seawater to remove unstable, attached silt and biofouling. The antifouling performance of each group of coatings was evaluated according to standard GB / T 5370-2007 "Antifouling Paint Samples Shallow Sea Immersion Test Method". The test results are as follows: Figure 13 As shown in Table 2, Figure 13 The study compares the surface fouling of the composite nanozyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 with that of the single nanozyme coatings in Comparative Example 1 (containing CeO2) and Comparative Example 2 (containing g-C3N4) after 180 days of seawater immersion. Table 2 below shows the biofouling coverage results of the composite nanoenzyme functional coatings in Example 1 (containing CeO2 / BiOBr-Y), Example 2 (containing CeO2 / BiOCl), and Example 4 (containing CeO2 / g-C3N4-1) under different immersion times:

[0110] As shown in Table 2 above, the biofouling coverage of the composite nanozyme functional coating (containing CeO2 / BiOBr-Y) in Example 1 was 6.31% after 60 days of immersion; the biofouling coverage of the composite nanozyme functional coating (containing CeO2 / BiOCl) in Example 2 reached 7.56% after 45 days of immersion; and the biofouling coverage of the composite nanozyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 was only 4.78% after 180 days of immersion, with an antifouling efficiency >95%. This result indicates that, at similarly low fouling levels, the composite nanozyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 has a significantly longer weathering period, maintaining the lowest fouling rate even after 180 days, demonstrating the best and most durable antifouling stability.

[0111] In addition, by Figure 13 It can be seen that after 180 days of seawater immersion, the surface of the composite nanoenzyme functional coating (containing CeO2 / g-C3N4-1) in Example 4 remained smooth, without blistering, cracking, or peeling, demonstrating good environmental tolerance and physical stability. In contrast, the blank control group was clearly covered by fouling organisms; the single nanoenzyme coatings in Comparative Example 1 (containing CeO2) and Comparative Example 2 (containing g-C3N4) also showed obvious biofouling, and their antifouling performance was significantly lower than that of the composite coating.

[0112] The above results fully demonstrate that the composite nanoenzyme functional coating of the present invention has efficient and stable marine antifouling capabilities.

[0113] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a cerium oxide / piezoelectric material composite nanoenzyme for an antifouling coating, characterized in that, Includes the following steps: S1. Disperse the cerium metal source and the piezoelectric material source in a solvent at a mass ratio of 1:(1-5) to form a uniform mixed system; S2. The mixed system in step S1 is subjected to phase formation and composite treatment to obtain cerium oxide / piezoelectric material composite. S3. After processing the cerium oxide / piezoelectric material composite in step S2, collect the solid product to obtain the cerium oxide / piezoelectric material composite nanozyme for antifouling coating.

2. The method for preparing cerium oxide / piezoelectric material composite nanoenzymes for antifouling coatings as described in claim 1, characterized in that, The phase formation and composite treatment is achieved by any of the following methods: (1) Precursor solution method: The phase formation and composite treatment in step S2 includes: drying and evaporating the solvent at 60-90°C, followed by calcination at 400-700°C for 2-5 hours under air or inert gas conditions at a heating rate of 2-10°C / min; Wherein, the cerium source is a cerium salt precursor and the piezoelectric material source is a piezoelectric material precursor; (2) Heterogeneous recombination method: The phase formation and composite treatment in step S2 includes: drying or heat treatment at 60-700℃ for 0.5-24h; Wherein, the cerium metal source is cerium oxide nanoparticles obtained from a cerium metal salt precursor, and the piezoelectric material source is a piezoelectric material obtained from a piezoelectric material precursor; (3) One-step hydrothermal / solvothermal method: The phase formation and composite treatment described in step S2 includes: performing a hydrothermal or solvothermal reaction at 80-200℃ for 6-24 hours; The cerium source is a cerium salt precursor, and the piezoelectric material source is a piezoelectric material precursor.

3. The preparation method of cerium oxide / piezoelectric material composite nanoenzyme for antifouling coating as described in claim 1, characterized in that, In step S1, an auxiliary agent is also added, and the amount of the auxiliary agent added is 0-30 wt.% of the mixture.

4. The method for preparing cerium oxide / piezoelectric material composite nanoenzymes for antifouling coatings as described in claim 2, characterized in that, The cerium salt precursor is selected from one or more of cerium nitrate, cerium chloride, cerium acetate, cerium sulfate, or cerium citrate.

5. The method for preparing cerium oxide / piezoelectric material composite nanoenzymes for antifouling coatings as described in claim 2, characterized in that, The piezoelectric material precursor is a nitrogen-containing organic precursor or a metal halide salt.

6. The method for preparing cerium oxide / piezoelectric material composite nanoenzymes for antifouling coatings as described in claim 5, characterized in that, The nitrogen-containing organic precursor is selected from one or more of urea, melamine, or dicyandiamide.

7. The method for preparing cerium oxide / piezoelectric material composite nanoenzymes for antifouling coatings as described in claim 5, characterized in that, The metal halide salt is bismuth halide, which is generated in situ from soluble bismuth salt and halide salt.

8. The method for preparing cerium oxide / piezoelectric material composite nanoenzymes for antifouling coatings as described in claim 5, characterized in that, The piezoelectric material is g-C3N4, BiOBr, or BiOCl.

9. The method for preparing cerium oxide / piezoelectric material composite nanoenzymes for antifouling coatings as described in claim 1, characterized in that, The solvent mentioned in step S1 is selected from one or more of deionized water or organic solvents.

10. The cerium oxide / piezoelectric composite nanoenzyme for antifouling coating prepared by the preparation method according to any one of claims 1-9.

11. The application of the cerium oxide / piezoelectric composite nanoenzyme for antifouling coatings as described in claim 10 in marine antifouling coatings.

12. A coating, characterized in that, Its active ingredient contains the cerium oxide / piezoelectric material composite nanoenzyme for antifouling coating as described in claim 10.

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