Energy storage type photo-generated cathode protection coating material and preparation method thereof

Abstract

The invention relates to an energy storage type photo-generated cathode protection coating material and a preparation method thereof, and belongs to the technical field of chemical materials. The coating material is a binary composite material which is composed of nanometer MoO3 and BiVO4. The preparation method comprises the following steps: firstly, preparing nano MoO3 by a precipitation method, and then preparing a nano MoO3 and BiVO4 binary composite material in situ by a low-temperature hydrothermal method, namely the coating material disclosed by the invention. In the coating material, nano MoO3 and BiVO4 are adopted to form a heterojunction material, so that the photoresponse range of BiVO4 is widened, and the photoelectron-hole separation efficiency is effectively improved; meanwhile, nano MoO3 is used as an energy storage material with high theoretical specific capacity, part of photo-induced electrons generated by BiVO4 can be stored in the form of a compound, and in a dark state environment, the electrons stored in MoO3 are released and quickly transferred to the surface of metal or a film-forming substrate, so that cathode protection of the metal in the dark environment is realized; the technical problems that in the prior art, nano BiVO4 is low in electron-hole separation efficiency and poor in metal surface adhesive force, and the cathode protection effect cannot be continued in the dark state are solved.

Description

Technical Field

[0001] The present invention relates to an energy storage type photocathode protection coating material and a preparation method thereof, specifically to a coating material that can store energy and has photocathode protection performance both under sunlight and in darkness and a preparation method thereof, belonging to the technical field of chemical materials. Background Art

[0002] Photogenerated cathodic protection (PCP) technology has been widely studied in recent years for metal corrosion protection due to its environmental friendliness, simple construction, and solar-powered design. Bismuth vanadate (BiVO4) is widely used in PCP technology due to its wide light absorption range, stable chemical properties, low price, and high catalytic activity. However, BiVO4 also has the following drawbacks: Its high carrier recombination rate significantly reduces its effectiveness in practical applications; the coupling between BiVO4 and the metal surface is also a key factor affecting the performance of PCP, and current contact methods require the construction of relatively complex devices; and, because PCP technology relies on light drive, BiVO4 cannot maintain its PCP effect in a dark environment. These drawbacks have hindered the practical application of BiVO4 in PCP technology.

[0003] To address these issues, current research is modifying BiVO4, such as by coupling it with semiconductor materials with energy storage properties to create heterojunctions. This not only reduces BiVO4's carrier recombination rate but also leverages the energy storage material's ability to store photoelectrons, achieving cathodic protection for metals in the dark. Zhanyuan Yang et al. (Direct Z-schemenanoporous BiVO4 / CdS quantum dots heterojunction composites as photoanodes for photocathodic protection of 316stainless steel under visible light) modified nano-BiVO4 with CdS semiconductor material, increasing the nano-BiVO4's photoresponse range. The heterojunction also significantly reduced the material's carrier recombination rate. Furthermore, due to the CdS material's energy storage properties, the composite maintained its cathodic protection effect for 14 hours in the dark after 10 hours of visible light irradiation, providing excellent photocathodic protection for 316 stainless steel.

[0004] Therefore, reducing the electron-hole recombination efficiency of BiVO4, enhancing the adhesion between the material and the metal surface, and achieving sustained photocathodic protection effect in a dark environment are of great significance for promoting the practical application of BiVO4 in photocathodic protection technology. Summary of the Invention

[0005] In response to the problems of low electron-hole separation efficiency, poor adhesion to metal surfaces, and inability to maintain cathodic protection effects in the dark, the present invention aims to provide an energy storage type photogenerated cathode protection coating material and a preparation method thereof. The coating material uses nano-MoO3 and BiVO4 to form a heterojunction material, which broadens the light response range of BiVO4 and effectively improves the photoelectron-hole separation efficiency. At the same time, nano-MoO3, as an energy storage material with a high theoretical specific capacity, can store some of the photogenerated electrons generated by BiVO4 in the form of compounds. When in a dark environment, the electrons stored in MoO3 are released and quickly transferred to the metal surface or film-forming substrate, thereby achieving cathodic protection of the metal in a dark environment.

[0006] The objectives of the present invention are achieved through the following technical solutions.

[0007] An energy storage type photogenerated cathode protection coating material, wherein the coating material is a binary composite material composed of nano MoO3 and BiVO4.

[0008] A method for preparing the energy storage type photogenerated cathode protection coating material of the present invention comprises the following steps:

[0009] Nano-MoO3 is first prepared by a precipitation method, and then a binary composite material of nano-MoO3 and BiVO4 is in situ prepared by a low-temperature hydrothermal method, namely the energy storage type photogenerated cathode protection coating material of the present invention.

[0010] Specifically, the low-temperature hydrothermal method for in-situ preparation of nano-MoO3 and BiVO4 binary composite materials comprises the following steps:

[0011] Bi salt and surfactant are added to a nitric acid solution while stirring in a water bath, and then a NaOH solution is added dropwise to the solution to adjust the pH of the system; V salt is added to the above solution to form a BiVO4 precursor solution; then nano-MoO3 is added and fully stirred in a water bath for reaction; finally, high-temperature precipitation is performed, the precipitate is separated, repeatedly washed, and then dried to obtain a nano-MoO3 and BiVO4 binary composite material.

[0012] Furthermore, the Bi salt is Bi(NO3)3·5H2O, the surfactant is sodium dodecylbenzenesulfonate, and the V salt is NH4VO3.

[0013] Furthermore, based on the total mass of water in the reaction system, i.e., the water in the nitric acid solution and the NaOH solution, being 100%, the mass fraction of the Bi salt is 4% to 5% of the mass fraction of the water, preferably 4.2%; the mass fraction of the surfactant is 0.5% to 1.5% of the mass fraction of the water, preferably 1%; and the mass fraction of the V salt is 4% to 5% of the mass fraction of the water, preferably 4.2%.

[0014] The stirring rate of the water bath is 800 r / min to 2000 r / min, preferably 1000 r / min; the temperature is 60° C. to 80° C., preferably 70° C.

[0015] The pH value of the system is pH=4-6, preferably 5.

[0016] The added amount of the nano-MoO3 is such that the molar ratio of Bi:Mo is 1:1 to 20:1, preferably 10:1.

[0017] The high temperature precipitation is performed at 100° C. to 150° C. in a vacuum or air atmosphere for 12 hours; preferably, the precipitation is performed at 120° C.

[0018] The washing step is to first add water to the precipitate for washing, then add anhydrous ethanol for washing, and repeat the washing.

[0019] Specifically, the steps of preparing nano-MoO3 by precipitation method are as follows:

[0020] A molybdenum source and a surfactant are added to water under stirring, and then a precipitant is added to the solution for ultrasonic treatment; after ultrasonic treatment, a precipitate is obtained by filtration, the precipitate is separated, repeatedly washed, and then dried to obtain nano-MoO3.

[0021] The molybdenum source is ammonium paramolybdate. Based on the mass fraction of water being 100%, the mass fraction of the molybdenum source is 3% to 4% of the mass fraction of water, preferably 3.2%.

[0022] The surfactant is sodium dodecylbenzenesulfonate. Based on the mass fraction of water being 100%, the mass fraction of the surfactant is 0.5% to 0.7% of the mass fraction of water, preferably 0.61%.

[0023] The precipitant is nitric acid. Based on the mass fraction of water being 100%, the mass fraction of the precipitant is 6% to 7% of the mass fraction of water, preferably 6.3%.

[0024] The washing step is to first add water to the precipitate for washing, then add anhydrous ethanol for washing, and repeat the washing.

[0025] The drying is carried out at 60° C. to 80° C. in an air atmosphere or in a vacuum for 10 hours; preferably, the drying is carried out at 70° C.

[0026] The basic principles of the present invention are as follows:

[0027] MoO3 is an n-type semiconductor with a high theoretical specific capacity and pseudocapacitive energy storage properties. When BiVO4 is excited by photons to generate photoelectrons, a portion of the photogenerated electrons are conducted to the metal surface to which it is coupled, causing the metal electrode potential to shift negatively, placing it in a protected state and preventing corrosion. Since the conduction band of nano-MoO3 is lower than that of BiVO4, another portion of the electrons migrate from BiVO4 to the nano-MoO3, improving the separation efficiency and greatly reducing the electron-hole recombination rate of BiVO4. At the same time, the electrons that migrate to the nano-MoO3 undergo a reduction reaction and are stored in the form of chemical energy. When in a dark environment, BiVO4 can no longer provide electrons to the metal, and the electrons stored in the MoO3 are slowly released and migrate to the metal surface, continuing the cathodic protection effect on the metal. Therefore, the present invention prepares a binary composite material composed of nano-MoO3 and BiVO4 by a low-temperature hydrothermal method, connects it to the metal, and can effectively improve the metal's corrosion resistance and form a photogenerated cathodic protection coating.

[0028] Beneficial effects

[0029] 1. The present invention provides an energy storage type photogenerated cathode protection coating material, wherein BiVO4 has excellent visible light absorption characteristics and can form a heterojunction material with nano-MoO3, thereby improving the hole-electron separation efficiency of the coating material, ensuring effective separation of carriers while improving the photoelectric conversion rate.

[0030] 2. The present invention provides an energy storage type photocathode protection coating material, which applies the pseudocapacitive energy storage properties of the energy storage material MoO3 to the photocathode protection technology. The energy storage properties of nano-MoO3 can store some of the photogenerated electrons generated by BiVO4 in the form of chemical energy. In a dark environment, the electrons are released and migrate to the surface of the protected metal, continuing the cathodic protection effect on the metal and promoting the practical application of in-situ photocathode protection technology.

[0031] 3. The present invention provides an energy storage-type photogenerated cathode protection coating material. MoO3 is an n-type semiconductor with a high theoretical specific capacity and pseudocapacitive energy storage properties. When BiVO4 is excited by photons to generate photoelectrons, a portion of the photogenerated electrons are conducted to the metal surface to which it is coupled, causing the metal electrode potential to shift negatively, thereby protecting it from corrosion. Because the conduction band of nano-MoO3 is lower than that of BiVO4, another portion of the electrons migrate from BiVO4 to nano-MoO3, improving separation efficiency and significantly reducing the electron-hole recombination rate of BiVO4. At the same time, the electrons that migrate to nano-MoO3 undergo a reduction reaction and are stored in the form of chemical energy. When in a dark environment, BiVO4 can no longer provide electrons to the metal, and the electrons stored in MoO3 are slowly released and migrate to the metal surface, continuing the cathodic protection effect on the metal.

[0032] 4. The present invention provides an energy storage type photogenerated cathode protection coating material. When the nanocomposite coating material is connected to the metal to be protected to form a coating, under simulated sunlight, the potential of the working electrode in the corrosion electrolytic cell can drop to about -800mV, which is about 400mV lower than the self-corrosion potential, and a significant cathode polarization phenomenon occurs, indicating that the photogenerated cathode protection effect of the coating material is significant.

[0033] 5. The present invention provides a method for preparing an energy storage type photogenerated cathode protection coating material, which in situ prepares nano-MoO3 and BiVO4 binary composite materials by a low-temperature hydrothermal method. The method is simple and the preparation conditions are controllable.

[0034] 6. The present invention provides a method for preparing an energy storage type photocathode protection coating material. The obtained material has the characteristics of uniform size, regular morphology, and uniform load distribution; it improves the interfacial bonding force between nano-MoO3 and BiVO4, which is beneficial to the transmission of photogenerated carriers, and can be used as a photocathode protection composite film material in anti-corrosion technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 These are UV-visible spectra of the energy storage type photogenerated cathode protection coating materials and pure BiVO4 prepared in Examples 1 to 3.

[0036] Figure 2 The fluorescence spectra of the energy storage type photogenerated cathode protection coating materials and pure BiVO4 prepared in Examples 1 to 3 are shown.

[0037] Figure 3 The current density diagrams are obtained from the 304 stainless steel working electrodes coated with the energy storage type photocathode protection coating and the pure BiVO4 coating prepared in Examples 1 to 3 under simulated sunlight irradiation.

[0038] Figure 4 This is the open circuit potential diagram of the 304 stainless steel working electrode coated with the energy storage type photocathode protection coating and coated with pure BiVO4 prepared in Example 2 under simulated sunlight irradiation. DETAILED DESCRIPTION

[0039] The present invention will be further explained below with reference to the accompanying drawings.

[0040] The energy storage type photogenerated cathode protection coating material and pure BiVO4 prepared in Example 1 were subjected to the following performance tests:

[0041] (1) UV-visible spectra: The coating material and pure BiVO4 were tested using a U-3900H UV-visible spectrophotometer (Hitachi) to characterize the optical absorption capacity of the coating material and pure BiVO4. The spectrum scanning range was 300 nm to 800 nm.

[0042] (2) Fluorescence spectra: The coating material and pure BiVO4 were tested using an FL-7000 fluorescence spectrometer to characterize the fluorescence emission capabilities of the coating material and pure BiVO4 and reveal the electron-hole separation capabilities of the materials. The excitation wavelength was 365 nm.

[0043] (3) Photogenerated cathodic protection test, the specific method is as follows:

[0044] A single-electrolytic cell electrochemical system was used. In the photoelectrolytic cell, pure BiVO₄ or the energy storage photocathodic protective coating material prepared in the examples was coated on 304SS to form a coating. The coating served as the working electrode and was placed in a 0.1 mol / L Na₂S solution. A saturated calomel electrode (SCE) served as the reference electrode, and a Pt electrode served as the counter electrode. A 300W high-voltage Xe lamp with an AM1.5 filter was used as a simulated sunlight source to directly illuminate the surface of the pure BiVO₄ or the coating material in the photoelectrolytic cell. The potential change and photocurrent density of the working electrode before and after illumination were measured using an Autolab 302N electrochemical workstation at a 0V bias. The change in open-circuit potential after the light was turned off was used to assess the duration of the coating's dark-state protection of the metal.

[0045] Example 1

[0046] An energy storage type photogenerated cathode protection coating material, wherein the coating material is a binary composite material composed of nano-MoO3 and BiVO4; the coating material is prepared by the following method:

[0047] (1) Deionized water was placed in a beaker, ammonium paramolybdate was dissolved in the deionized water, sodium dodecylbenzenesulfonate was added and stirred for 30 minutes; the beaker was placed in an ultrasonic cleaning machine, the pH value of the solution was adjusted to 2 with 1M HNO3, ultrasonicated for 20 minutes and then filtered, the precipitate obtained after filtration was first washed with water, then washed repeatedly with anhydrous ethanol, and then dried in a 70°C oven for 10 hours to obtain nano-MoO3;

[0048] Wherein, based on the mass fraction of deionized water as 100%, the mass fraction of the molybdenum source is 3.2% of the mass fraction of water; the mass fraction of the surfactant sodium dodecylbenzenesulfonate is 0.61% of the mass fraction of water; and the mass fraction of the precipitant nitric acid is 6.3% of the mass fraction of water.

[0049] (2) Bi(NO3)3·5H2O was added to 1M HNO3 solution and stirred in a water bath at a stirring rate of 1000 r / min until completely dissolved. Under the same stirring in a water bath, sodium dodecylbenzenesulfonate was added and stirred evenly. Then 1M NaOH solution was added dropwise to the solution to adjust the system to a pH of 5. Then NH4VO3 was added to the above mixed solution to form a BiVO4 precursor solution. Then nano-MoO3 was added to make the molar ratio of Bi:W 1:1, and the mixture was stirred in a water bath at 70°C for 5h. The mixture was transferred to a forced air drying oven and precipitated at 120°C for 12h. The precipitate was separated by centrifugation at a centrifugal rate of 5000 r / min for 5min, and washed alternately with deionized water and anhydrous ethanol several times until the pH was 7. The mixture was dried to obtain a nano-MoO3 and BiVO4 binary composite material, which is an energy storage type photogenerated cathode protection coating material, denoted as B1M1.

[0050] Wherein, based on the total mass of water in the reaction system, i.e., the total mass of water in the nitric acid solution and the NaOH solution, being 100%, the mass fraction of Bi(NO3)3·5H2O is 4.2%; the mass fraction of the surfactant sodium dodecylbenzenesulfonate is 1% of the mass fraction of water; and the mass fraction of NH4VO is 4.2% of the mass fraction of water.

[0051] Example 2

[0052] An energy storage type photogenerated cathode protection coating material, wherein the coating material is a binary composite material composed of nano-MoO3 and BiVO4; the coating material is prepared by the following method:

[0053] (1) Same as step (1) in Example 1.

[0054] (2) Add nano-MoO3 to make the molar ratio of Bi:W be 10:1, and the remaining steps are the same as those in step (2) of Example 1 to obtain a nano-MoO3 and BiVO4 binary composite material, which is an energy storage type photogenerated cathode protection coating material, denoted as B 10 M1.

[0055] Example 3

[0056] An energy storage type photogenerated cathode protection coating material, wherein the coating material is a binary composite material composed of nano-MoO3 and BiVO4; the coating material is prepared by the following method:

[0057] (1) Same as step (1) in Example 1.

[0058] (2) Add nano-MoO3 to make the molar ratio of Bi:W be 20:1, and the remaining steps are the same as those in step (2) of Example 1 to obtain a nano-MoO3 and BiVO4 binary composite material, which is an energy storage type photogenerated cathode protection coating material, denoted as B20 M1.

[0059] Example 4

[0060] An energy storage type photogenerated cathode protection coating material, wherein the coating material is a binary composite material composed of nano-MoO3 and BiVO4; the coating material is prepared by the following method:

[0061] (1) Deionized water was placed in a beaker, ammonium paramolybdate was dissolved in the deionized water, sodium dodecylbenzenesulfonate was added and stirred for 30 minutes; the beaker was placed in an ultrasonic cleaning machine, the pH value of the solution was adjusted to 2 with 1M HNO3, ultrasonicated for 20 minutes and then filtered, the precipitate obtained after filtration was first washed with water, then washed repeatedly with anhydrous ethanol, and then dried in a 60°C oven for 10 hours to obtain nano-MoO3;

[0062] Wherein, based on the mass fraction of deionized water as 100%, the mass fraction of the molybdenum source is 3% of the mass fraction of water; the mass fraction of the surfactant sodium dodecylbenzenesulfonate is 0.5% of the mass fraction of water; and the mass fraction of the precipitant nitric acid is 6% of the mass fraction of water.

[0063] (2) Bi(NO3)3·5H2O was added to 1M HNO3 solution and stirred in a water bath at a stirring rate of 800 r / min until completely dissolved. Under the same stirring in a water bath, sodium dodecylbenzenesulfonate was added and stirred evenly. Then 1M NaOH solution was added dropwise to the solution to adjust the system to a pH of 4. Then NH4VO3 was added to the above mixed solution to form a BiVO4 precursor solution. Then nano-MoO3 was added to make the molar ratio of Bi:W be 10:1. The mixture was stirred in a water bath at 60°C for 5 h. The mixture was moved into a forced air drying oven and precipitated at 100°C for 12 h. The precipitate was separated by centrifugation at a centrifugal rate of 5000 r / min for 5 min. The mixture was washed alternately with deionized water and anhydrous ethanol several times until the pH was 7 and dried to obtain a nano-MoO3 and BiVO4 binary composite material, which is an energy storage type photogenerated cathode protection coating material.

[0064] Wherein, based on the total mass of water in the reaction system, i.e., the water in the nitric acid solution and the NaOH solution, being 100%, the mass fraction of Bi(NO3)3·5H2O is 4%; the mass fraction of the surfactant sodium dodecylbenzenesulfonate is 0.5% of the mass fraction of water; and the mass fraction of NH4VO is 4% of the mass fraction of water.

[0065] Example 5

[0066] An energy storage type photogenerated cathode protection coating material, wherein the coating material is a binary composite material composed of nano-MoO3 and BiVO4; the coating material is prepared by the following method:

[0067] (1) Deionized water was placed in a beaker, ammonium paramolybdate was dissolved in the deionized water, sodium dodecylbenzenesulfonate was added and stirred for 30 minutes; the beaker was placed in an ultrasonic cleaning machine, the pH value of the solution was adjusted to 2 with 1M HNO3, ultrasonicated for 20 minutes and then filtered, the precipitate obtained after filtration was first washed with water, then washed repeatedly with anhydrous ethanol, and then dried in an oven at 80°C for 10 hours to obtain nano-MoO3;

[0068] Wherein, based on the mass fraction of deionized water as 100%, the mass fraction of the molybdenum source is 4% of the mass fraction of water; the mass fraction of the surfactant sodium dodecylbenzenesulfonate is 0.7% of the mass fraction of water; and the mass fraction of the precipitant nitric acid is 7% of the mass fraction of water.

[0069] (2) Bi(NO3)3·5H2O was added to 1M HNO3 solution and stirred in a water bath at a stirring rate of 2000r / min until completely dissolved. Under the same stirring in a water bath, sodium dodecylbenzenesulfonate was added and stirred evenly. Then 1M NaOH solution was added dropwise to the solution to adjust the system to a pH of 6. Then NH4VO3 was added to the above mixed solution to form a BiVO4 precursor solution. Then nano-MoO3 was added to make the molar ratio of Bi:W be 10:1. The mixture was stirred in a water bath at 80℃ for 5h. The mixture was moved into a forced air drying oven and precipitated at 150℃ for 12h. The precipitate was separated by centrifugation at a centrifugal rate of 5000r / min for 5min. The mixture was washed alternately with deionized water and anhydrous ethanol several times until the pH was 7 and dried to obtain a nano-MoO3 and BiVO4 binary composite material, which is an energy storage type photogenerated cathode protection coating material.

[0070] Wherein, based on the total mass of water in the reaction system, i.e., the water in the nitric acid solution and the NaOH solution, being 100%, the mass fraction of Bi(NO3)3·5H2O is 5%; the mass fraction of the surfactant sodium dodecylbenzenesulfonate is 1.5% of the mass fraction of water; and the mass fraction of NH4VO is 5% of the mass fraction of water.

[0071] Performance Testing

[0072] The performance tests of the energy storage type photogenerated cathode protection coating materials and pure BiVO4 prepared in Examples 1 to 5 were conducted, and the results are as follows:

[0073] (1) Figure 1 The UV-visible spectra of the coating materials prepared in Examples 1-3 and pure BiVO4 are plotted, with wavelength on the abscissa and absorption intensity on the ordinate. It can be seen that the introduction of nano-MoO3 expands the composite's light absorption range into the visible light region, indicating that the heterojunction structure constructed with MoO3 and BiVO4 enhances the material's ability to capture photons.

[0074] The coating materials prepared in Examples 4 and 5 gave similar results to the coating materials prepared in Examples 1 to 3.

[0075] (2) Figure 2 The fluorescence spectra of the coating materials and pure BiVO4 prepared in Examples 1 to 3 (excitation wave 365nm) are shown in the figure. The horizontal axis is the wavelength and the vertical axis is the absorption intensity. It can be seen that the composite material has obvious fluorescence quenching phenomenon, which indicates that there is effective charge transfer in the material. 10 The fluorescence emission peak of the M1 sample is the weakest, and the hole-electron recombination rate of the material is also the lowest.

[0076] The coating materials prepared in Examples 4 and 5 gave similar results to the coating materials prepared in Examples 1 to 3.

[0077] (3) Figure 3 The current density diagram of the coating prepared by the coating material obtained by Examples 1 to 3 and the 304 stainless steel working electrode coated with pure BiVO4 coating under simulated sunlight. The horizontal axis is time, the vertical axis is current density, on represents light, and off represents turning off the light source, i.e., dark environment. Figure 3 It can be seen that compared with the working electrode coated with pure BiVO4, the working electrode coated with the coating material shows a higher photocurrent, indicating that it has a better photoelectric conversion effect. This is mainly because the combination of nano-MoO3 and BiVO4 can reduce the recombination of photogenerated electron-hole pairs, expand the light absorption range, and effectively improve the utilization rate of light. Moreover, after repeated illumination, the photocurrent has a high degree of reproducibility, indicating that the coating material has stable performance. 10 The photocurrent density of the M1 sample is the highest, which is consistent with the fluorescence results.

[0078] The coatings prepared from the coating materials prepared in Examples 4 and 5 had similar results to those of Examples 1 to 3.

[0079] (4) Figure 4 The coating material (B 10 Open circuit potential diagram of the 304 stainless steel working electrode coated with a coating prepared by M1 sample and a pure BiVO4 coating under simulated sunlight, where the horizontal axis is time and the vertical axis is potential. On indicates light, and off indicates turning off the light source, i.e., a dark environment.

[0080] Depend on Figure 4 It can be seen that when the 304 stainless steel working electrode is coated with pure BiVO4 coating, the corrosion potential of the 304 stainless steel working electrode is reduced to about -650mV, which has a certain photoinduced cathodic protection effect; when coated with B 10When the M1 coating material is used, the potential of the 304 stainless steel working electrode can drop to about -800mV, and the potential gradually decreases with the extension of the light exposure time; when the light source is cut off, the potential of the 304 stainless steel working electrode begins to rise, and the potential of the working electrode coated with pure BiVO4 coating rises rapidly to the initial potential, while the potential of the working electrode coated with B 10 The working electrode potential of the M1 coating material slowly increased and did not return to its initial potential within 15 hours, demonstrating its ability to maintain cathodic protection even in the dark. When exposed to light, MoO3 acts as an energy storage material, storing some of the photoelectrons generated by the excited BiVO4. In the dark, these photoelectrons are slowly released and transferred to the metal surface, maintaining the cathodic protection effect.

[0081] The coatings prepared from the coating materials prepared in Examples 1, 3, 4 and 5 had similar results to that of Example 2.

[0082] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An energy storage type photogenerated cathode protection coating material, characterized by: The coating material is a binary composite material composed of nano MoO3 and BiVO4.

2. A method for preparing the energy storage type photogenerated cathode protection coating material according to claim 1, characterized in that: Nano-MoO3 is first prepared by precipitation method, and then nano-MoO3 and BiVO4 binary composite material is in situ prepared by low-temperature hydrothermal method, which is an energy storage type photogenerated cathode protection coating material.

3. The method for preparing an energy storage type photogenerated cathode protection coating material according to claim 2, characterized in that: The method for in-situ preparation of nano-MoO3 and BiVO4 binary composite materials by low-temperature hydrothermal method is as follows: Bi salt and surfactant are added to a solvent while stirring in a water bath, and then NaOH solution is added dropwise to the solution to adjust the pH of the system; V salt is added to the above solution to form a BiVO4 precursor solution; then nano-MoO3 is added and fully stirred in a water bath for reaction; finally, high-temperature precipitation is performed, the precipitate is separated, repeatedly washed, and then dried to obtain a nano-MoO3 and BiVO4 binary composite material.

4. The method for preparing an energy storage type photogenerated cathode protection coating material according to claim 3, characterized in that: The Bi salt is Bi(NO3)3·5H2O. Based on the mass fraction of water being 100%, the mass fraction of the Bi salt is 4% to 5% of the mass fraction of water. The surfactant is sodium dodecylbenzenesulfonate, and the mass fraction of the surfactant is 0.5% to 1.5% of the mass fraction of water, based on the mass fraction of water being 100%; The V salt is NH4VO3. Based on the mass fraction of water being 100%, the mass fraction of the V salt is 4% to 5% of the mass fraction of water. The added amount of nano-MoO3 is such that the molar ratio of Bi:Mo is 1:1 to 20:

1.

5. The method for preparing an energy storage type photogenerated cathode protection coating material according to claim 4, characterized in that: Taking the water mass fraction as 100%: The mass fraction of Bi salt is 4.2% of the mass fraction of water; The mass fraction of surfactant is 1% of the mass fraction of water; The mass fraction of V salt is 4.2% of the mass fraction of water; The added amount of nano-MoO3 is Bi:Mo molar ratio of 10:

1.

6. The method for preparing an energy storage type photogenerated cathode protection coating material according to claim 3, characterized in that: The stirring rate of the water bath is 800 r / min to 2000 r / min, and the temperature is 60°C to 80°C; The pH value of the system is 4 to 6; High temperature precipitation is 100℃~150℃, and precipitation is carried out in vacuum or air atmosphere for 12 hours; The washing step is to first add deionized water to the precipitate, then add anhydrous ethanol to wash, and repeat the washing.

7. The method for preparing an energy storage type photogenerated cathode protection coating material according to claim 6, characterized in that: The water bath was stirred at a rate of 1000 r / min and a temperature of 70°C; The pH value of the system is 5; The high temperature precipitation is 120°C and the precipitation is carried out in a vacuum or air atmosphere for 12 hours.

8. A method for preparing an energy storage type photogenerated cathode protection coating material according to any one of claims 2 to 7, characterized in that: The steps for preparing nano-MoO3 by precipitation method are as follows: A molybdenum source and a surfactant are added to water under stirring, and then a precipitant is added to the solution for ultrasonic treatment; after ultrasonic treatment, a precipitate is obtained by filtration, the precipitate is separated, repeatedly washed, and then dried to obtain nano-MoO3.

9. The method for preparing an energy storage type photogenerated cathode protection coating material according to claim 8, characterized in that: The molybdenum source is ammonium paramolybdate. Based on the mass fraction of water being 100%, the mass fraction of the molybdenum source is 3% to 4% of the mass fraction of water. The surfactant is sodium dodecylbenzenesulfonate, and the mass fraction of the surfactant is 0.5% to 0.7% of the mass fraction of water, based on the mass fraction of water being 100%; The precipitant is nitric acid. Based on the mass fraction of water being 100%, the mass fraction of the precipitant is 6% to 7% of the mass fraction of water. Washing is to first add deionized water to the precipitate for washing, then add anhydrous ethanol for washing, and wash repeatedly; The drying is carried out at 60°C to 80°C in air or vacuum for 10 hours.

10. The method for preparing an energy storage type photogenerated cathode protection coating material according to claim 9, characterized in that: Taking the water mass fraction as 100%: The mass fraction of the molybdenum source is 3.2% of the mass fraction of water; The mass fraction of surfactant is 0.61% of the mass fraction of water; The mass fraction of the precipitant is 6.3% of the mass fraction of water; The drying was carried out at 70° C. in air atmosphere or in vacuum for 10 hours.

Images