Anti-corrosion, anti-fouling and antibacterial multifunctional Z-type heterojunction photo-anode and preparation method thereof

Abstract

The invention belongs to the technical field of corrosion inhibition of ocean engineering structure metal materials, and particularly relates to an anti-corrosion, anti-fouling and antibacterial multifunctional Z-type heterojunction photo-anode and a preparation method thereof. The photoanode is of a Z-type heterojunction structure, and selective recombination of electron-hole pairs can be achieved, so that electrons with higher reducing capacity are reserved on a conduction band of one semiconductor, and holes with higher oxidizing capacity are reserved on a valence band of the other semiconductor. Photoelectrons are effectively injected into protected metal to realize photoelectric cathode protection; meanwhile, strong oxidizing holes and generated active oxygen species (such as. OH) can efficiently degrade organic matters and biological membranes, kill bacteria and inhibit algae, and the anti-corrosion, anti-fouling and anti-algae functions are synchronously achieved. The problem that a traditional photo-anode is single in function is solved, and the photo-anode has the advantages of being high in sunlight utilization rate, high in oxidation-reduction capacity, good in stability and the like and can be widely applied to the fields of ocean engineering corrosion prevention, medical instrument surface treatment, water treatment and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of corrosion inhibition of marine engineering structure metal materials, and particularly relates to a multifunctional Z-type heterojunction photoanode for corrosion prevention, antifouling and antibacterial and a preparation method thereof. BACKGROUND

[0002] The corrosion and biofouling problems of engineering structure metal materials (such as ships, offshore platforms, submarine pipelines, port facilities, etc.) in marine environments are great challenges to the development of the marine industry, causing huge economic losses and safety hazards every year. These metal structures are simultaneously threatened by physical and chemical corrosion and microbial corrosion. Traditional protection methods, such as organic coatings and cathodic protection, are widely used but have limitations, especially in dealing with microbial attachment, biofilm formation and the resulting biological corrosion.

[0003] Currently, the protection of marine metal structures mainly relies on the following technologies: (1) Organic anticorrosion coating: By acting as a physical barrier to isolate the metal substrate from the corrosive medium, it is the most widely used technology. However, the coating is prone to aging, cracking and peeling during service, and once defects occur, corrosion will quickly spread at the defects. More importantly, most traditional coatings do not have the ability to inhibit microbial attachment, and the organic substances such as plasticizers contained in them may even become a source of nutrition for microorganisms, accelerating the formation of biofilms. (2) Cathodic protection: Including sacrificial anode method and impressed current method, by providing electrons to the protected metal to polarize it to the stable potential region, thereby inhibiting the anodic dissolution of the metal. This method is mature, but has obvious shortcomings: sacrificial anodes are consumed quickly and need to be replaced regularly; impressed current method requires continuous power supply, has high energy consumption and is difficult to apply; most importantly, cathodic protection can only prevent electrochemical corrosion, and has no effect on microbial corrosion and biofouling. On the contrary, the hydroxyl ions (OH⁻) and hydrogen gas (H2) produced on the cathode surface can change the microenvironment at the interface and even promote the activity of certain sulfate-reducing bacteria (SRB), exacerbating microbial corrosion. (3) Antifouling paint: The early widely used toxic agent release type paint such as organotin (TBT) is effective, but has been banned by international conventions due to its devastating impact on the marine ecological environment. The current mainstream tin-free self-polishing antifouling paint mainly removes attached organisms by continuously hydrolyzing on the surface, but its antifouling effective period is limited, and there is still a potential ecological risk of slow release of chemical substances.

[0004] To solve the energy consumption and environmental protection problems of traditional technology, photoelectrochemical cathodic protection technology emerges as the times require. The technology uses the photogenerated electrons generated by the semiconductor photoanode under light to migrate to the connected metal, so that the metal is cathodically polarized, thereby realizing "green" and energy-saving corrosion protection. However, the traditional semiconductor photoanode faces the problems of serious photogenerated carrier recombination and narrow spectral response range. In addition, the original design of the traditional photoanode is only to provide electrons for cathodic protection, and the holes generated by the photoanode are usually consumed by water or a sacrificial agent in the electrolyte, and are not effectively utilized. It cannot solve the problem of biofouling and microbial corrosion ubiquitous in marine environment, and the single function makes its effect in practical application greatly discounted.

[0005] The traditional II heterojunction promotes the spatial separation of photogenerated electrons and holes through band interlacing, to a certain extent, improves the charge separation efficiency, but its redox ability is low. This is a fundamental contradiction for multifunctional applications that require strong reducing electrons for cathodic protection and strong oxidizing holes for sterilization and antifouling.

[0006] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies of the prior art. SUMMARY

[0007] The purpose of the present application is to provide a corrosion and antifouling and antibacterial multifunctional Z-type heterojunction photoanode and a preparation method thereof, to help the redox activity of the photoanode, to solve the problem of single function of the photoanode in the prior art, low solar energy utilization, and inability to simultaneously cope with electrochemical corrosion, biological corrosion and algal attachment, and to provide a new, green and efficient solution for long-term protection of marine engineering facilities.

[0008] In order to achieve the above-mentioned purpose, the present application provides the following technical solution: a corrosion and antifouling and antibacterial multifunctional Z-type heterojunction photoanode and a preparation method thereof, comprising a conductive substrate and a Z-type heterojunction grown on the conductive substrate; the Z-type heterojunction functional layer is composed of two kinds of semiconductor materials with matching energy band structures, forming a Z-type heterojunction structure capable of realizing selective recombination and migration of photogenerated electron-hole pairs, for simultaneously realizing corrosion and antifouling and light sterilization functions.

[0009] Preferably, the two kinds of semiconductor materials of the Z-type heterojunction functional layer comprise a first semiconductor material and a second semiconductor material; the conduction band potential of the first semiconductor material is more negative than that of the second semiconductor material; and the valence band potential of the second semiconductor material is more positive than that of the first semiconductor material.

[0010] Preferably, the first semiconductor material is a reducing semiconductor; and the second semiconductor material is an oxidizing semiconductor.

[0011] Preferably, the reducing semiconductor is one of tin indium sulfide (SnIn4S8), cuprous phosphide (Cu3P), cobalt indium sulfide (CoIn2S4), nickel cobaltate (NiCo2O4); the oxidizing semiconductor is one of zinc gallate (ZnGa2O4), barium titanate (BaTiO3), zinc stannate (Zn2SnO4), silver phosphate (Ag3PO4).

[0012] Preferably, the conductive substrate is one of FTO conductive glass, ITO conductive glass, titanium foil, stainless steel foil, copper foil or steel bar.

[0013] The application also provides a preparation method of the Z-type heterojunction photoanode, which adopts the technical scheme as follows: the Z-type heterojunction photoanode is prepared by the method as described above.

[0014] Preferably, the preparation method of the Z-type heterojunction photoanode comprises the following steps:

[0015] (1) cleaning and pretreating the conductive substrate;

[0016] (2) preparing the first semiconductor material on the pretreated conductive substrate;

[0017] (3) loading the second semiconductor material on the first semiconductor material layer to form the Z-type heterojunction photoanode.

[0018] Preferably, the preparation method of the first semiconductor material and the second semiconductor material comprises one or two of hydrothermal method, sol-gel method, chemical precipitation method, high-temperature decomposition method, gas phase phosphorization method or continuous ion layer adsorption reaction method.

[0019] The application also provides the application of the Z-type heterojunction photoanode as described above, which adopts the technical scheme as follows: the Z-type heterojunction photoanode as described above is used for providing photo-cathode protection to metal structural members in a photo-electrochemical system; meanwhile, corrosion and pollution prevention and algae resistance are realized for the Z-type heterojunction photoanode itself and the surrounding environment.

[0020] Preferably, the object of the photo-cathode protection of the Z-type heterojunction photoanode is metal structural members in marine engineering, including steel parts of ships, offshore platforms, submarine pipelines or bridges.

[0021] Preferably, the application field of the Z-type heterojunction photoanode in pollution prevention and algae inhibition includes marine pollution prevention, medical equipment surface treatment or water treatment disinfection.

[0022] Beneficial effects:

[0023] Compared with the prior art, the application realizes the synergy and integration of three functions. The application ingeniously utilizes the unique charge separation mechanism of the Z-type heterojunction to simultaneously and efficiently realize three functions.

[0024] (1) Photocathodic protection: Strongly reducing electrons enriched on the conduction band of the reductive semiconductor can be injected into the metal structure (such as low carbon steel) connected thereto efficiently, causing cathodic polarization thereof, and the potential is shifted to the safe zone, thereby inhibiting the electrochemical corrosion of the metal from the root.

[0025] (2) Antifouling: Strongly oxidizing holes enriched on the valence band of the oxidative semiconductor can react with water molecules or hydroxyl ions in the solution to generate active oxygen species (ROS) such as hydroxyl radicals (·OH) and superoxide radicals (O2⁻), which can degrade the attached organic substances and bacterial cell walls / membranes without selectivity, effectively preventing the formation and accumulation of biofouling, and effectively killing corrosive microorganisms such as sulfate-reducing bacteria (SRB) and Escherichia coli.

[0026] (3) Algae inhibition: Strongly oxidizing holes enriched on the valence band of the oxidative semiconductor can directly attack and destroy the biofilm attached to the metal surface, effectively inhibiting the growth of algae such as barnacles. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. Among them:

[0028] Figure 1 The open circuit potential (OCP) curves of the ZnGa2O4 photoanode of Comparative Example 1, the SnIn4S8 photoanode of Comparative Example 2, and the Z-type heterojunction photoanode (SnIn4S8-ZnGa2O4) of Example 1 coupled to stainless steel under intermittent light conditions;

[0029] Figure 2 The electrochemical impedance spectroscopy (EIS) curves of the Cu3P photoanode of Comparative Example 3, the BaTiO3 photoanode of Comparative Example 4, and the Z-type heterojunction photoanode (Cu3P-BaTiO3) of Example 2 under light-on conditions;

[0030] Figure 3 The ultraviolet-visible light absorption (UV-Vis) curves of the Zn2SnO4 photoanode of Comparative Example 5, the CoIn2S4 photoanode of Comparative Example 6, and the Z-type heterojunction photoanode (CoIn2S4-Zn2SnO4) of Example 3;

[0031] Figure 4 The sterilization effect of the Z-type heterojunction photoanode (NiCo2O4-Ag3PO4) of Example 4 on Escherichia coli and Staphylococcus aureus;

[0032] Figure 5Inhibition effect diagram of Chlorella on the Z-type heterojunction photoanode (SnIn4S8-ZnGa2O4) of Example 1, the Z-type heterojunction photoanode (Cu3P-BaTiO3) of Example 2, the Z-type heterojunction photoanode (CoIn2S4-Zn2SnO4) of Example 3 and the Z-type heterojunction photoanode (NiCo2O4-Ag3PO4) of Example 4. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0034] The present application will be described in detail below with reference to the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0035] The present application aims at the problem that the existing photoanode material has single function, low solar energy utilization rate and cannot simultaneously cope with electrochemical corrosion, biological corrosion and algae attachment, and provides a corrosion and pollution resistant and bacteriostatic multifunctional Z-type heterojunction photoanode and a preparation method thereof, which provides a new and green and efficient solution for long-acting protection of marine engineering facilities.

[0036] In order to achieve the above object, the present application provides the following technical solutions: a corrosion and pollution resistant and bacteriostatic multifunctional Z-type heterojunction photoanode and a preparation method thereof, comprising a conductive substrate and a Z-type heterojunction grown on the conductive substrate; the Z-type heterojunction functional layer is composed of two kinds of semiconductor materials with matched energy band structures, which constitutes a Z-type heterojunction structure capable of realizing selective recombination and migration of photoinduced electron-hole pairs, and is used for simultaneously realizing corrosion and pollution resistance and light-illuminated antibacterial function.

[0037] Preferably, the two kinds of semiconductor materials of the Z-type heterojunction functional layer comprise a first semiconductor material and a second semiconductor material; the conduction band potential of the first semiconductor material is more negative than that of the second semiconductor material; and the valence band potential of the second semiconductor material is more positive than that of the first semiconductor material.

[0038] Preferably, the first semiconductor material is a reductive semiconductor; and the second semiconductor material is an oxidative semiconductor.

[0039] Preferably, the reducing semiconductor is one of tin indium sulfide (SnIn4S8), cuprous phosphide (Cu3P), cobalt indium sulfide (CoIn2S4), nickel cobaltate (NiCo2O4); the oxidizing semiconductor is one of zinc gallate (ZnGa2O4), barium titanate (BaTiO3), zinc stannate (Zn2SnO4), silver phosphate (Ag3PO4).

[0040] Preferably, the conductive substrate is one of FTO conductive glass, ITO conductive glass, titanium foil, stainless steel foil, copper foil or steel bar.

[0041] The application also provides a preparation method of the Z-type heterojunction photoanode, which adopts the technical scheme as follows: the Z-type heterojunction photoanode is prepared by the method as above.

[0042] Preferably, the preparation method of the Z-type heterojunction photoanode comprises the following steps:

[0043] (1) cleaning and pretreating the conductive substrate;

[0044] (2) preparing the first semiconductor material on the pretreated conductive substrate;

[0045] (3) loading the second semiconductor material on the first semiconductor material layer to form the Z-type heterojunction photoanode.

[0046] Preferably, the preparation method of the first semiconductor material and the second semiconductor material comprises one or two of hydrothermal method, sol-gel method, chemical precipitation method, high-temperature decomposition method, gas phase phosphorization method or continuous ion layer adsorption reaction method.

[0047] The application also provides the application of the Z-type heterojunction photoanode as above, which adopts the technical scheme as follows: the Z-type heterojunction photoanode as above is used for providing photo-cathode protection to metal structural members in a photo-electrochemical system; meanwhile, corrosion and pollution prevention and algae resistance are realized for the Z-type heterojunction photoanode itself and the surrounding environment.

[0048] Preferably, the photo-cathode protection object of the Z-type heterojunction photoanode is metal structural members in marine engineering, including steel parts of ships, offshore platforms, submarine pipelines or bridges.

[0049] Preferably, the application field of the Z-type heterojunction photoanode in pollution prevention and algae inhibition includes marine pollution prevention, medical equipment surface treatment or water treatment disinfection.

[0050] The Z-type heterojunction photoanode for corrosion and pollution prevention and bacteria inhibition and the preparation method thereof will be described in detail through specific embodiments as below.

[0051] Embodiment 1

[0052] The preparation method of the SnIn4S8 nanosheet-ZnGa2O4 nanosheet (SnIn4S8-ZnGa2O4) Z-type heterojunction photoanode of the embodiment comprises the following steps:

[0053] (1) Preparation of ZnGa2O4 nanoparticles:

[0054] 5 mmol of zinc acetate (Zn(Ac)2) and 4 mmol of gallium nitrate (Ga(NO3)3) were added into 30 ml of deionized water, and then NaOH was slowly added dropwise to adjust the solution pH to 8 to obtain a ZnGa2O4 precursor solution. The FTO was placed in a high-pressure reaction kettle, the ZnGa2O4 precursor solution was poured into the kettle, and the kettle was heated at 180°C for 10 h. After cooling, the FTO was taken out, washed and dried, and then placed in a muffle furnace and calcined at 600°C to obtain FTO loaded with ZnGa2O4 nanosheets.

[0055] (2) SnIn4S8 nanosheet compounding:

[0056] SnIn4S8 nanosheets were synthesized by a hydrothermal method. 2 mmol of tin tetrachloride (SnCl4), 8 mmol of indium trichloride (InCl3) and 16 mmol of thioacetamide (TAA) were dissolved in 25 mL of deionized water to obtain a SnIn4S8 precursor solution. The SnIn4S8 precursor solution was poured into a polytetrafluoroethylene liner, and the FTO loaded with ZnGa2O4 nanoparticles was placed in the liner, and the liner was heated at 160°C for 12 h. After cooling, the sample was taken out, washed and dried to obtain a SnIn4S8 nanosheet-ZnGa2O4 nanosheet (SnIn4S8-ZnGa2O4) Z-type heterojunction photoanode.

[0057] Example 2

[0058] The preparation method of the Cu3P nanosphere-BaTiO3 nanosheet (Cu3P-BaTiO3) Z-type heterojunction photoanode of the embodiment comprises the following steps:

[0059] (1) Preparation of Cu3P nanospheres:

[0060] Cu3P nanospheres were prepared by a gas phase phosphorization method. A pre-processed copper foil was placed in a quartz boat at the downstream of a tube furnace. 2 g of sodium hypophosphite (NaH2PO2) was weighed and placed in a quartz boat at the upstream of the tube furnace. Under an argon atmosphere, the temperature was raised to 300°C at a rate of 5 ℃ / min, and the phosphorization reaction was maintained for 2 h. After cooling to room temperature, the sample was taken out to obtain a copper foil with Cu3P nanospheres grown on the surface.

[0061] (2) BaTiO3 nanosheet compounding:

[0062] 5 mmol of barium acetate (Ba(Ac)2) was dissolved in 30 mL of deionized water to form a first solution; another 5 mmol of tetrabutyl titanate (Ti(OBu)4) was dissolved in 30 mL of anhydrous ethanol to form a second solution. The second solution was slowly added to the first solution, and after stirring for 30 min, a NaOH solution was added to adjust the pH to 9.5 to obtain a BaTiO3 precursor solution. The copper foil with Cu3P nanospheres grown on the surface was added to the reaction kettle and then poured into the BaTiO3 precursor solution, and hydrothermal treatment was performed at 180°C for 20 h. After cooling, the copper foil was taken out and washed with deionized water to obtain a Cu3P nanosphere-BaTiO3 nanosheet (Cu3P-BaTiO3) Z-type heterojunction photoanode.

[0063] Example 3

[0064] The preparation method of the CoIn2S4 quantum dot-Zn2SnO4 nanosheet (CoIn2S4-Zn2SnO4) Z-type heterojunction photoanode of this example comprises the following steps:

[0065] (1) Preparation of Zn2SnO4 nanosheet:

[0066] ITO conductive glass was selected as the substrate. 6 mmol of zinc acetate (Zn(Ac)2) and 3 mmol of tin tetrachloride (SnCl4) were dissolved in 20 mL of deionized water and stirred for 30 min, and then NaOH was slowly added to the solution to adjust the pH to 11.5 to obtain a Zn2SnO4 precursor solution. The Zn2SnO4 precursor solution was poured into a polytetrafluoroethylene liner with ITO conductive glass, and heated at 180°C for 16 h. After natural cooling, the ITO was taken out and washed with deionized water to obtain a Zn2SnO4 nanosheet sample.

[0067] (2) CoIn2S4 quantum dot sensitized Zn2SnO4 nanosheet:

[0068] CoIn2S4 quantum dots were deposited by a successive ion layer adsorption reaction (SILAR). The ITO conductive glass loaded with the Zn2SnO4 nanosheet was sequentially immersed in Co 2+ (Co(NO3)2 ethanol solution), In 3+ (InNO3 ethanol solution), and S 2- (Na2S methanol solution) precursor solutions, and repeated for 15 cycles to obtain a CoIn2S4 quantum dot-Zn2SnO4 nanosheet (CoIn2S4-Zn2SnO4) Z-type heterojunction photoanode after washing.

[0069] Example 4

[0070] The preparation method of the NiCo2O4 nanorod-Ag3PO4 nanosphere (NiCo2O4-Ag3PO4) Z-type heterojunction photoanode of the embodiment comprises the following steps:

[0071] (1) Preparation of NiCo2O4 nanorod:

[0072] FTO conductive glass is selected as the substrate. 2 mmol of nickel nitrate (Ni(NO3)2), 4 mmol of cobalt nitrate (Co(NO3)2) and 5 mmol of urea (CO(NH2)2) are weighed into a beaker, 20 ml of deionized water is added and stirred for 30 min. After stirring is completed, the solution is poured into a polytetrafluoroethylene liner with FTO conductive glass, and reacted at 140°C for 6h. After cooling, the FTO conductive glass is taken out and placed in a muffle furnace, heated at 350°C for 5h, and the FTO conductive glass loaded with NiCo2O4 nanorods is obtained.

[0073] (2) Ag3PO4 nanosphere complexation:

[0074] Ag3PO4 nanospheres are prepared by chemical deposition. 30 mmol of silver nitrate (AgNO3) is dissolved in 20 ml of deionized water, and 10 ml of 2 mol / L sodium hydrogen phosphate (Na2HPO4) aqueous solution is slowly added, stirred for 1h, and the precipitate is obtained by filtration. The precipitate is washed and dried, dispersed in anhydrous ethanol, and a film is formed on the FTO conductive glass loaded with NiCo2O4 nanorods by drop coating to obtain a NiCo2O4 nanorod-Ag3PO4 nanosphere (NiCo2O4-Ag3PO4) Z-type heterojunction photoanode.

[0075] Comparative Example 1

[0076] The preparation method of the ZnGa2O4 photoanode of the comparative example is different from that of Example 1 only in that step (2) is omitted; the rest is the same as Example 1.

[0077] Comparative Example 2

[0078] The preparation method of the SnIn4S8 photoanode of the comparative example is different from that of Example 1 only in that step (1) is omitted; clean FTO conductive glass is loaded into a polytetrafluoroethylene liner; the rest is the same as Example 1.

[0079] Comparative Example 3

[0080] The preparation method of the Cu3P photoanode of the comparative example is different from that of Example 2 only in that step (2) is omitted; the rest is the same as Example 2.

[0081] Comparative Example 4

[0082] The preparation method of the BaTiO3 photoanode of the present comparative example is different from that of Example 2 only in that step (1) is omitted; the copper foil with Cu3P nanospheres grown on the surface is replaced by clean FTO conductive glass; and the rest is consistent with Example 2.

[0083] Comparative Example 5

[0084] The preparation method of the Zn2SnO4 photoanode of the present comparative example is different from that of Example 3 only in that step (2) is omitted; and the rest is consistent with Example 3.

[0085] Comparative Example 6

[0086] The preparation method of the CoIn2S4 photoanode of the present comparative example is different from that of Example 3 only in that step (1) is omitted; the conductive substrate is clean ITO conductive glass; and the rest is consistent with Example 3.

[0087] Comparative Example 7

[0088] The preparation method of the NiCo2O4 photoanode of the present comparative example is different from that of Example 4 only in that step (2) is omitted; and the rest is consistent with Example 4.

[0089] Comparative Example 8

[0090] The preparation method of the Ag3PO4 photoanode of the present comparative example is different from that of Example 4 only in that step (1) is omitted; the conductive substrate is clean FTO conductive glass; and the rest is consistent with Example 4.

[0091] Experimental Example

[0092] 1. The Z-type heterojunction photoanode (SnIn4S8-ZnGa2O4) of Example 1, the ZnGa2O4 photoanode of Comparative Example 1 and the SnIn4S8 photoanode of Comparative Example 2 were respectively coupled with stainless steel, and then open circuit potential tests were carried out under intermittent light and light conditions:

[0093] The open circuit potential test was carried out using a Gamry Interface 5000E electrochemical workstation. A double electrolytic cell made of polytetrafluoroethylene was used for the test, and a quartz glass light transmission hole was left on the side to ensure that the light could pass through and be incident on the surface of the photoelectrode. A 300W xenon lamp was used as the excitation light source to simulate the light intensity and light range of the full spectrum of sunlight.

[0094] The results of the open circuit potential test under intermittent light are shown in Figure 1 Figure 1 ​It can be seen that the photovoltage drop of the ZnGa2O4 photoanode of Comparative Example 1 coupled with stainless steel is 0.09 V; the photovoltage drop of the SnIn4S8 photoanode of Comparative Example 2 coupled with stainless steel is -0.61 V; and the photovoltage drop of the Z-type heterojunction photoanode (SnIn4S8-ZnGa2O4) of Example 1 coupled with stainless steel is from -0.24 V to -0.99 V, and the photovoltage drop reaches 0.75 V, which indicates that the Z-type heterojunction photoanode (SnIn4S8-ZnGa2O4) of Example 1 can provide more photo-generated electrons for stainless steel under light, and has better photoelectrocathodic protection performance.

[0095] 2. Under light conditions, the Z-type heterojunction photoanode (Cu3P-BaTiO3) of Example 2, the Cu3P photoanode of Comparative Example 3 and the BaTiO3 photoanode of Comparative Example 4 were subjected to alternating current impedance (EIS) test:

[0096] The alternating current impedance (EIS) test was performed using a Gamry Interface 5000E electrochemical workstation, the electrolyte solution was 3.5 wt% NaCl solution, the test temperature was room temperature, and the alternating current voltage amplitude was set to 0.01 V.

[0097] The alternating current impedance test results are shown in Figure 2 It can be seen from Figure 2 that compared with the Cu3P photoanode of Comparative Example 3 and the BaTiO3 photoanode of Comparative Example 4, the Z-type heterojunction photoanode (Cu3P-BaTiO3) of Example 2 has the smallest impedance arc radius under light conditions, indicating that the charge transfer impedance of the Z-type heterojunction photoanode (Cu3P-BaTiO3) of Example 2 is the smallest. This indicates that the construction of the Z-type heterojunction of Example 2 improves the migration efficiency of photo-generated carriers and effectively improves the separation rate of photo-generated electron-hole pairs.

[0098] 3. The Z-type heterojunction photoanode (CoIn2S4-Zn2SnO4) of Example 3, the Zn2SnO4 photoanode of Comparative Example 5 and the CoIn2S4 photoanode of Comparative Example 6 were subjected to ultraviolet-visible light absorption (UV-Vis) test:

[0099] The ultraviolet-visible light absorption (UV-Vis) test was performed using a Japan-Shimadzu-UV-3600 plus spectrometer, the vertical axis was set as the light absorption intensity, and the wavelength range was set as 200 nm to 800 nm.

[0100] The ultraviolet-visible light absorption spectrum is shown in Figure 3 It can be seen from Figure 3It can be seen that the light absorption band edge of Zn2SnO4 in Comparative Example 5 is located at 332nm, and the light absorption band edge of CoIn2S4 in Comparative Example 6 is located at 545nm. However, the light absorption band edge of the Z-type heterojunction photoanode (CoIn2S4-Zn2SnO4) in Example 3 is significantly red-shifted to 586nm, and the light absorption intensity within the absorption range is also significantly enhanced. This indicates that the presence of the Z-type heterojunction improves the utilization efficiency of visible light by the semiconductor material and enhances its light absorption capability.

[0101] 4. Antibacterial tests were conducted on the Z-type heterojunction photoanode (NiCo2O4–Ag3PO4 composite film) of Example 4, the NiCo2O4 photoanode of Comparative Example 7, and the Ag3PO4 photoanode of Comparative Example 8:

[0102] Two typical bacterial species, *Escherichia coli* and *Staphylococcus aureus*, were selected for antibacterial testing. The bacterial strains were cultured on petri dishes using the spread plate method. First, the photoanode sample and bacterial solution were co-cultured under a cold light source for 1 hour to construct the photocatalytic antibacterial experimental system. Then, the treated bacterial solution was evenly spread on the surface of a solid culture medium and placed in a 25°C incubator for 24 hours to ensure sufficient proliferation of surviving bacteria and the formation of visible colonies. Finally, the number of surviving colonies was calculated using image processing software, and the change in colony count visually evaluated the antibacterial effect of different photoanodes.

[0103] Antibacterial test results as follows Figure 4 As shown; from Figure 4 It can be seen that the Z-type heterojunction photoanode (NiCo2O4–Ag3PO4) in Example 4 exhibited a kill efficiency of 96.27% and 94.78% against Escherichia coli and Staphylococcus aureus, respectively, which is significantly better than the NiCo2O4 photoanode in Comparative Example 5 and the Ag3PO4 photoanode in Comparative Example 6. This indicates that the unique carrier migration mechanism of the Z-type heterojunction effectively suppresses photogenerated electron-hole recombination while retaining strong redox properties, enabling the Z-type heterojunction photoanode to continuously generate a large number of highly effective bactericidal reactive oxygen species (e.g., ·OH, ·O). 2- It exhibits excellent antibacterial properties.

[0104] 5. Anti-algae experiments were conducted on the Z-type heterojunction photoanode (SnIn4S8-ZnGa2O4) of Example 1, the Z-type heterojunction photoanode (Cu3P-BaTiO3) of Example 2, the Z-type heterojunction photoanode (CoIn2S4-Zn2SnO4) of Example 3, and the Z-type heterojunction photoanode (NiCo2O4-Ag3PO4) of Example 4:

[0105] In the anti-algae experiment, a homogeneous algal solution was constructed using Chlorella vulgaris and divided into equal volumes in experimental and control containers containing semiconductors. The containers were placed in a simulated natural light environment, with a temperature controlled at 25-30℃ and a light / dark cycle of 12h / 12h, for 7 days. After 7 days, samples were taken to measure absorbance values, which were then converted to algal concentration. Differences in algal concentration were compared to evaluate the anti-algae activity.

[0106] Results of anti-algae experiments as follows Figure 5 Show: From Figure 5 It can be seen that the Z-type heterojunction photoanodes of Example 1 (SnIn4S8-ZnGa2O4), Example 2 (Cu3P-BaTiO3), Example 3 (CoIn2S4-Zn2SnO4), and Example 4 (NiCo2O4-Ag3PO4) all exhibit excellent anti-algae properties. This indicates that the construction of Z-type heterostructures can effectively promote the separation and transport of photogenerated carriers, thereby enabling the material to generate more substances with strong redox activity (e.g., ·OH, ·O) under illumination. 2- These active substances can disrupt the structure and function of algal cells, fully demonstrating the key role of Z-shaped heterojunctions in enhancing photocatalytic anti-algae performance. Meanwhile, from... Figure 5 It can be seen that the Z-type heterojunction photoanode (SnIn4S8-ZnGa2O4) in Example 1 has the highest algae inhibition rate, indicating that the Z-type heterojunction photoanode in Example 1 has the best algae inhibition effect.

[0107] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A Z-type heterojunction photoanode, characterized in that, The application relates to a Z-type heterojunction functional layer and a preparation method and application thereof. The Z-type heterojunction functional layer comprises a conductive substrate and a Z-type heterojunction functional layer grown on the conductive substrate. The Z-type heterojunction functional layer is composed of two kinds of semiconductor materials with matched energy band structures, and forms a Z-type heterojunction structure capable of realizing selective recombination and migration of photo-generated electron-hole pairs, so as to realize the functions of corrosion and pollution prevention and illumination antibacterial function.

2. The Z-type heterojunction photoanode according to claim 1, characterized in that, The two kinds of semiconductor materials of the Z-type heterojunction functional layer comprise a first semiconductor material and a second semiconductor material. The conduction band potential of the first semiconductor material is more negative than that of the second semiconductor material. The valence band potential of the second semiconductor material is more positive than that of the first semiconductor material.

3. The Z-type heterojunction photoanode according to claim 2, wherein The first semiconductor material is a reducing semiconductor, and the second semiconductor material is an oxidizing semiconductor.

4. The Z-type heterojunction photoanode according to claim 3, characterized in that, The reducing semiconductor is one of tin indium sulfide (SnIn4S8), cuprous phosphide (Cu3P), cobalt indium sulfide (CoIn2S4) and nickel cobaltate (NiCo2O4). The oxidizing semiconductor is one of zinc gallate (ZnGa2O4), barium titanate (BaTiO3), zinc stannate (Zn2SnO4) and silver phosphate (Ag3PO4).

5. The Z-type heterojunction photoanode according to claim 1, wherein The morphology of the Z-type heterojunction functional layer is one or two of a nanowire array, a nanotube array, a nanosheet array, a nanosphere, a nanofilm, a porous film or a quantum dot sensitization structure.

6. The Z-type heterojunction photoanode of claim 1, wherein The conductive substrate is one of FTO conductive glass, ITO conductive glass, a titanium foil, a stainless steel foil, a copper foil or a steel bar.

7. A method for preparing a Z-type heterojunction photoanode, characterized in that, The Z-type heterojunction photoanode is prepared by the method in any one of claims 1-6.

8. The method for producing a Z-type heterojunction photoanode according to claim 7, wherein The preparation method comprises the following steps: (1) cleaning and pretreating the conductive substrate; (2) preparing the first semiconductor material on the pretreated conductive substrate; (3) loading the second semiconductor material on the first semiconductor material layer to form the Z-type heterojunction photoanode.

9. The method for producing a Z-type heterojunction photoanode according to claim 8, wherein The preparation method of the first semiconductor material and the second semiconductor material comprises one or two of a hydrothermal method, a sol-gel method, a chemical precipitation method, a high-temperature decomposition method, a gas phase phosphorization method or a continuous ion layer adsorption reaction method.

10. Use of a Z-type heterojunction photoanode, characterized in that The Z-type heterojunction photoanode is prepared by the method in any one of claims 1-9.

11. Use of a Z-type heterojunction photoanode according to claim 10, characterized in that, The application range comprises: (1) being used for providing photoelectrode protection for metal structural members in a photoelectrochemical system; (2) simultaneously realizing corrosion and pollution prevention and algae resistance for itself and the surrounding environment.

12. Use of a Z-type heterojunction photoanode according to claim 11, characterized in that, The photoelectrode protection object of the Z-type heterojunction photoanode is a metal structural member in marine engineering, including a steel part of a ship, an offshore platform, a submarine pipeline or a bridge.

13. Use of a Z-type heterojunction photoanode according to claim 11, characterized in that, The application field of the Z-type heterojunction photoanode in the aspects of antifouling and algae inhibition comprises marine antifouling, medical equipment surface treatment or water treatment disinfection.

Images