A controllable energy storage potential photoanode and its preparation method and application

Abstract

The present invention discloses a controllable energy storage potential photoanode and its preparation method and application, which belong to the field of photoelectric cathode protection technology. The preparation method comprises the following steps: ultrasonicating FTO conductive glass in an acetone solution and transferring it to a hydrothermal kettle; adding deionized water to a beaker, weighing sodium tungstate dihydrate, adding it to water and stirring to dissolve, subsequently adding concentrated sulfuric acid and stirring to obtain a precursor solution; transferring it to a hydrothermal kettle, then placing it in an oven for heating, taking out the conductive glass and placing it in a muffle furnace for calcining to obtain a WO3 film; taking isopropyl titanate and adding it to ethanol and stirring, then transferring it to a hydrothermal kettle with a WO3 film, then placing it in an oven for heating, taking out the conductive glass and placing it in a muffle furnace for calcining to obtain a WO3-TiO2 controllable energy storage potential photoanode. The composite heterojunction system constructed by the present invention not only has the energy storage characteristics of WO3, but also has higher photoelectric cathode protection performance, and can provide 120mV in-situ protection for 304SS.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric cathode protection, and in particular to a controllable energy storage potential photoanode film, a preparation method thereof, and applications thereof. Background Art

[0002] Harsh environments characterized by high salt spray, high radiation, and high temperatures pose significant challenges to corrosion protection for metal equipment. Electrochemical cathodic protection (ECP) technology, with its advantages of directness and thoroughness, has been widely adopted in island and reef engineering equipment and facilities. However, existing sacrificial anode and impressed current CPP technologies are time-consuming, energy-intensive, and require significant human and material resources.

[0003] The development of clean, sustainable photocathode protection technology based on the photovoltaic effect of semiconductors and utilizing existing light energy resources has important practical significance and economic value. However, due to regional, temporal, and seasonal variations, photocathode protection technology struggles to provide sustained corrosion protection for metals in low-light or no-light conditions. Therefore, there is an urgent need to develop a photoanode material with controllable energy storage capabilities. By storing the abundant daylight energy and intelligently and adapting it to nighttime or low-light environments, it can achieve sustained corrosion protection for island and reef engineering equipment in a variety of application scenarios.

[0004] In the field of photocathodic protection (PCP), semiconductor photoanodes are key to controlling the corrosion protection performance of the entire system. TiO2 is widely used in PCP due to its simple preparation process, low cost, and environmentally friendly properties. However, its high carrier recombination rate (the recombination of photogenerated electrons and holes) significantly reduces its photoelectric conversion efficiency, significantly reducing its corrosion protection effectiveness and slowing its application in PCP. Summary of the Invention

[0005] The present invention provides a photoanode film with controllable energy storage potential, its preparation method, and its application. Based on the established principles of heterostructure construction, this paper constructs a Type II composite photoanode heterojunction system with the energy storage semiconductor WO3 and TiO2 to address the aforementioned issues. Furthermore, addressing the drawbacks of existing energy storage photoanode heterojunctions, which are complex to prepare and difficult to control the energy storage potential of the energy storage semiconductor, the present invention constructs a TiO2-WO3 composite photoanode with controllable energy storage potential through a simple in-situ growth strategy, and applies it to metal corrosion protection.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for preparing a controllable energy storage potential photoanode comprises the following steps:

[0008] (1) Ultrasonicate the FTO conductive glass in acetone solution and transfer it to a hydrothermal reactor;

[0009] (2) Add deionized water to a beaker, weigh sodium tungstate dihydrate, add it to the water and stir to dissolve, then add concentrated sulfuric acid and stir to obtain a precursor solution with a pH value of 0.1-3;

[0010] (3) The precursor solution is transferred to a hydrothermal reactor, and then placed in an oven for heating. The FTO conductive glass is taken out and placed in a muffle furnace for calcination to obtain a WO3 thin film;

[0011] (4) Isopropyl titanate was added to ethanol and stirred, and then transferred to a hydrothermal reactor with a WO3 film, and then placed in an oven for heating. The FTO conductive glass was taken out and placed in a muffle furnace for calcination to obtain a WO3-TiO2 controllable energy storage potential photoanode.

[0012] The mass volume ratio of Na2WO4﹒2H2O and isopropyl titanate is (6-8): 1 g / ml.

[0013] Wherein, in step (1), the ultrasonic time is 20-40 minutes.

[0014] Wherein, in step (2), the mass volume ratio of sodium tungstate dihydrate and deionized water is (0.08-0.12): 1 g / ml.

[0015] Wherein, in step (3), the temperature of heating in an oven is 90-110° C., and the heating time is 2-4 hours; the temperature of calcining in a muffle furnace is 500-600° C., and the calcining time is 1-3 hours.

[0016] Wherein, in step (4), the volume ratio of isopropyl titanate to ethanol is 1:(50-70).

[0017] Wherein, in step (4), the temperature of heating in an oven is 160-200° C., and the heating time is 8-12 hours; the temperature of calcining in a muffle furnace is 500-600° C., and the calcining time is 1-3 hours.

[0018] The present invention also provides a controllable energy storage potential photoanode, which is made by the above-mentioned preparation method.

[0019] The present invention also provides an application of a controllable energy storage potential photoanode in the field of corrosion protection.

[0020] The present invention develops a preparation method for constructing a TiO2-WO3 composite photoanode with controllable energy storage potential through a simple in-situ growth strategy, and applies it to the corrosion protection of metals in various environments.

[0021] The heterojunction system constructed by the present invention can not only achieve the spatial separation of photogenerated electrons and holes, but also realize the storage and release process of photogenerated electrons by utilizing the reversible transformation of WO3 and Na2WO4. However, the existing TiO2 photoanodes for corrosion protection are generally derived from the anodic oxidation process of Ti foil, which not only makes the construction process of the heterojunction more complicated, but also cannot be applied to the subsequent photoanode coating process. At the same time, each semiconductor in the type II heterojunction composite system will affect the photoelectric conversion efficiency of the entire system. The relatively positive conduction band potential of the energy storage semiconductor WO3 limits the overall energy storage potential of the heterojunction system, thereby affecting the corrosion protection performance of the entire system.

[0022] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0023] 1. The composite heterojunction system constructed by WO3 and TiO2 in the present invention not only has the energy storage characteristics of WO3, but also has high photocathodic protection performance, which can provide 120mV in-situ protection for 304SS.

[0024] 2. The controllable energy storage potential WO3 photoanode film of this invention can be directly used for photocathodic protection of metals in marine environments, resolving the problem of insufficient driving force caused by the relatively positive coupling potential between existing energy storage photoanodes and metals. This invention provides valuable experience for the construction of WO3-based composite heterojunction systems, particularly those with controllable energy storage potential, and promotes the application of WO3 photoanode materials in the field of marine corrosion protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 X-ray diffraction spectra of various WO3 films (prepared in different pH environments).

[0026] Figure 2 SEM images of various WO3 films (different pH preparation environments a: pH = 0.1, b: pH = 0.7, c: pH = 1.5, d: pH = 3.0).

[0027] Figure 3 Linear sweep voltammograms of various WO3 films (prepared in different pH environments) (simulated marine environment, 3.5wt% NaCl).

[0028] Figure 4 Open circuit potential curves of various WO3 films (prepared in different pH environments) coupled with 304SS (simulated marine environment, 3.5wt% NaCl).

[0029] Figure 5 Open circuit potential curves of WO3 and WO3-TiO2 coupled with 304SS (simulated marine environment, 3.5wt% NaCl). DETAILED DESCRIPTION

[0030] The following will be combined with specific embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a photoanode with controllable energy storage potential, comprising the following steps:

[0033] (1) Ultrasonicate the FTO conductive glass in acetone solution for 30 min and transfer it to a hydrothermal reactor;

[0034] (2) Add 60 ml of deionized water to a beaker, weigh 6.9 g of sodium tungstate dihydrate, add it to the water and stir for 10 minutes to dissolve, then add concentrated sulfuric acid and stir to obtain a precursor solution with a pH of 0.1;

[0035] (3) The precursor solution was transferred to a hydrothermal reactor and then placed in an oven and heated at 100 °C for 3 h. The FTO conductive glass was taken out and placed in a muffle furnace and calcined at 550 °C for 2 h to obtain a WO3 thin film.

[0036] (4) Take 1 mL of isopropyl titanate and add it to 60 mL of ethanol and stir. Then transfer it to a hydrothermal reactor with a WO3 film, and then put it into an oven and heat it at 180 °C for 10 h. Take out the FTO conductive glass and put it into a muffle furnace and calcine it at 550 °C for 2 h to obtain a WO3-TiO2 controllable energy storage potential photoanode.

[0037] Example 2

[0038] This embodiment provides a method for preparing a photoanode with controllable energy storage potential, comprising the following steps:

[0039] (1) Ultrasonicate the FTO conductive glass in acetone solution for 20 min and transfer it to a hydrothermal reactor;

[0040] (2) Add 75 ml of deionized water to a beaker, weigh 8 g of sodium tungstate dihydrate, add it to the water and stir for 10 min to dissolve, then add concentrated sulfuric acid and stir to obtain a precursor solution with a pH of 0.7;

[0041] (3) The precursor solution was transferred to a hydrothermal reactor and then placed in an oven and heated at 90 °C for 4 h. The FTO conductive glass was taken out and placed in a muffle furnace and calcined at 600 °C for 1 h to obtain a WO3 thin film.

[0042] (4) Take 1 mL of isopropyl titanate and add it to 50 mL of ethanol and stir. Then transfer it to a hydrothermal kettle with a WO3 film, then place it in an oven and heat it at 160 °C for 12 h. Take out the FTO conductive glass and place it in a muffle furnace and calcine it at 600 °C for 1 h to obtain a WO3-TiO2 controllable energy storage potential photoanode.

[0043] Example 3

[0044] This embodiment provides a method for preparing a photoanode with controllable energy storage potential, comprising the following steps:

[0045] (1) Ultrasonicate the FTO conductive glass in acetone solution for 40 min and transfer it to a hydrothermal reactor;

[0046] (2) Add 67 ml of deionized water to a beaker, weigh 8 g of sodium tungstate dihydrate, add it to the water and stir for 10 min to dissolve, then add concentrated sulfuric acid and stir to obtain a precursor solution with a pH of 1.5;

[0047] (3) The precursor solution was transferred to a hydrothermal reactor and then placed in an oven and heated at 110 °C for 2 h. The FTO conductive glass was taken out and placed in a muffle furnace and calcined at 500 °C for 3 h to obtain a WO3 thin film.

[0048] (4) Take 1 mL of isopropyl titanate and add it to 70 mL of ethanol and stir. Then transfer it to a hydrothermal kettle with a WO3 film, then put it into an oven and heat it at 200 °C for 8 h. Take out the FTO conductive glass and put it into a muffle furnace and calcine it at 500 °C for 3 h to obtain a WO3-TiO2 controllable energy storage potential photoanode.

[0049] Example 4

[0050] This embodiment provides a method for preparing a photoanode with controllable energy storage potential, comprising the following steps:

[0051] (1) Ultrasonicate the FTO conductive glass in acetone solution for 30 min and transfer it to a hydrothermal reactor;

[0052] (2) Add 60 ml of deionized water to a beaker, weigh 6.9 g of sodium tungstate dihydrate, add it to the water and stir for 10 minutes to dissolve, then add concentrated sulfuric acid and stir to obtain a precursor solution with a pH of 3;

[0053] (3) The precursor solution was transferred to a hydrothermal reactor and then placed in an oven and heated at 100 °C for 3 h. The FTO conductive glass was taken out and placed in a muffle furnace and calcined at 550 °C for 2 h to obtain a WO3 thin film.

[0054] (4) Take 1 mL of isopropyl titanate and add it to 65 mL of ethanol and stir. Then transfer it to a hydrothermal kettle with a WO3 film, then place it in an oven and heat it at 180°C for 10 h. Take out the FTO conductive glass and place it in a muffle furnace and calcine it at 550°C for 2 h to obtain a WO3-TiO2 controllable energy storage potential photoanode.

[0055] Performance Testing

[0056] 1. X-ray diffraction test: X-ray diffraction test was performed on the WO3-TiO2 controllable energy storage potential photoanode prepared in Examples 1-4. The X-ray diffraction spectrum is shown in FIG. Figure 1 As shown in the figure (wherein, 0.1-WO3 indicates the sample obtained in Example 1, 0.7-WO3 indicates the sample obtained in Example 2, 1.5-WO3 indicates the sample obtained in Example 3, 3.0-WO3 indicates the sample obtained in Example 4, and the instructions in the following other tests are the same), as the pH increases, WO3 gradually transforms from a monoclinic phase to a triclinic phase. When the pH is in the range of 0.1-1.5, the 002 / 020 crystal plane intensity ratio of WO3 gradually decreases, indicating that the crystal plane orientation of WO3 decreases in sequence with increasing pH. In summary, pH is an important factor in regulating the crystal plane orientation of WO3.

[0057] 2. SEM test: The WO3-TiO2 controllable energy storage potential photoanode prepared in Examples 1-4 was subjected to SEM test, wherein the SEM spectrum (a: ordinary carbon nitride film, b: solid capture type photoanode film) is as follows Figure 2 As shown in the figure, all WO3 films have a nanosheet morphology, and the thickness of the nanosheets decreases with increasing pH. It is worth noting that the flake morphology of 3-WO3 changes significantly, which once again confirms that pH affects the crystal orientation of WO3, resulting in different morphological characteristics.

[0058] 3. Photocurrent density test: The test conditions are: simulated marine environment, 3.5wt% NaCl. The linear sweep voltammetry curves of various WO3 films (prepared in different pH environments) are as follows: Figure 3 As shown in Figure 2, the photocurrent densities of 0.1-WO3, 1.5-WO3, and 3-WO3 films in a simulated ocean environment are 27, 13, and 6 μA / cm, respectively. 2 Generally speaking, the magnitude of the photocurrent density is directly proportional to the photoelectric conversion efficiency. This phenomenon shows that the photoelectric conversion efficiency of WO3 decreases with the gradual increase of pH.

[0059] 4. Photoinduced open circuit potential test: The photoinduced open circuit potential test was used to investigate the photocathodic protection performance of various WO3 films on 304SS. The test conditions were a simulated marine environment with 3.5wt% NaCl. The open circuit potential curves of various WO3 films (prepared at different pH environments) coupled with 304SS are shown in the figure below. Figure 4 As shown, the initial coupling potentials of 0.1-WO3, 0.7-WO3, 1.5-WO3, and 3-WO3 films with 304SS were -0.15, -0.13, -0.06, and -0.01 V, respectively. After one illumination cycle, the coupling potentials decreased to -0.15, -0.13, -0.07, and -0.02 V, respectively. The coupling potentials exhibited an anodic polarization trend with increasing pH, indicating a gradual attenuation of the photocathodic protection performance. Compared to the 3-WO3 film, the potential decay of 0.1-WO3,3 after multiple cycles was significantly reduced (20 vs 60 mV), indicating that the 0.1-WO3 film possesses superior energy storage properties. In summary, by manipulating the preparation conditions of WO3, its energy storage properties and photocathodic protection performance can be effectively controlled.

[0060] At the same time, 0.1-WO3 film was used to in situ assemble WO3-TiO2 heterogeneous system. The open circuit potential curves of WO3 and WO3-TiO2 coupled with 304SS are shown in Figure 2. Figure 5 As shown in the figure, the composite heterojunction system constructed by WO3 and TiO2 not only has the energy storage characteristics of WO3, but also has higher photocathodic protection performance (far better than WO3-based heterojunction systems constructed by various oxides), which can provide 120mV on-site protection for 304SS.

[0061] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a controllable energy storage potential photoanode, characterized in that The steps include: (1) Ultrasonicate the FTO conductive glass in acetone solution and transfer it to a hydrothermal reactor; (2) Add deionized water to a beaker, weigh sodium tungstate dihydrate, add it to the water and stir to dissolve, then add concentrated sulfuric acid and stir to obtain a precursor solution with a pH value of 0.1-3; the mass volume ratio of sodium tungstate dihydrate to deionized water is (0.08-0.12): 1 g / ml; (3) The precursor solution is transferred to a hydrothermal reactor, and then placed in an oven for heating. The FTO conductive glass is taken out and placed in a muffle furnace for calcination to obtain a WO3 thin film. (4) adding isopropyl titanate to ethanol and stirring, then transferring it to a hydrothermal reactor with a WO3 film, and then heating it in an oven. Taking out the FTO conductive glass and calcining it in a muffle furnace to obtain a WO3-TiO2 controllable energy storage potential photoanode; the volume ratio of isopropyl titanate to ethanol is 1: (50-70); The mass volume ratio of sodium tungstate dihydrate and isopropyl titanate is (6-8): 1 g / ml.

2. The method for preparing a controllable energy storage potential photoanode according to claim 1, characterized in that: In step (1), the ultrasonication time is 20-40 min.

3. The method for preparing a controllable energy storage potential photoanode according to claim 1, wherein: In step (3), the temperature of the oven is 90-110°C and the heating time is 2-4 hours; the temperature of the muffle furnace is 500-600°C and the calcination time is 1-3 hours.

4. The method for preparing a controllable energy storage potential photoanode according to claim 1, wherein: In step (4), the temperature of heating in an oven is 160-200°C, and the heating time is 8-12 hours; the temperature of calcining in a muffle furnace is 500-600°C, and the calcining time is 1-3 hours.

5. A controllable energy storage potential photoanode, characterized in that The invention is prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the controllable energy storage potential photoanode according to claim 5 in the field of corrosion protection.

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