Method for removing tetravalent tin on surface of stannous niobate through reduction method and application

Abstract

The invention provides a method for removing tetravalent tin on the surface of stannous niobate through a reduction method and application, and relates to the technical field of photocatalysis and photoelectrocatalysis. The method comprises the following steps: infiltrating a stannous niobate electrode material in an electrolyte solution, so that the surface of stannous niobate is in full contact with the electrolyte solution; bias voltage is applied to the stannous niobate electrode material, so that the tetravalent tin on the surface of the stannous niobate is subjected to reduction reaction to be removed, and the charge shielding layer formed on the surface of the stannous niobate by the tetravalent tin is removed. By adopting the technical scheme, the reduction dissolution of tetravalent tin on the surface of stannous niobate is effectively regulated and controlled by controlling the composition of the electrolyte solution and applying the bias voltage, so that the problem of relatively low photovoltage caused by Fermi level pinning due to the existence of the tetravalent tin is solved, the recombination of charges at tetravalent tin sites is also reduced, and the photoelectric conversion efficiency is improved. Therefore, the purpose of cleaning the surface and restoring the surface to the initial state is achieved.

Description

Technical Field

[0001] This invention relates to the fields of photocatalysis and photoelectrocatalysis, specifically to a method and application for removing tetravalent tin from the surface of stannous niobate by reduction. Background Technology

[0002] Energy shortage and environmental degradation are two major challenges facing society today. Photocatalysis and photoelectrocatalysis are novel energy acquisition methods in which semiconductors absorb solar energy to generate electrons and holes, thereby reducing and oxidizing water into hydrogen and oxygen or converting low-value organic matter into high-value organic matter. However, this process places high demands on the semiconductor, which not only has a suitable band gap position, but also the crystallinity, morphology, internal carrier concentration and surface properties of the semiconductor material together determine the material's performance.

[0003] Stannous niobate materials have attracted widespread attention due to their suitable band gap and band position. The photocurrent density of stannous niobate reported in the prior art can reach 1 mA / cm². 2 (1.23 V vs. RHE), but the actual photocurrent value of the product is far lower than its theoretical photocurrent value (7.9 mA / cm). 2 One significant influencing factor is the easy oxidation of divalent tin to tetravalent tin on the surface of stannous niobate, forming a charge shielding layer that prevents charge transfer from the interior to the surface, thus greatly degrading the performance of stannous niobate. Furthermore, the oxidation process from divalent to tetravalent tin occurs extremely rapidly, occurring almost instantaneously upon light application to the electrode. This results in Fermi level pinning, causing the photovoltage generated under illumination to be far lower than its theoretical value. Ineffective charge separation and the resulting charge recombination centers lead to charge annihilation at these sites. Therefore, removing this charge shielding layer without damaging the substrate and forming a new, defect-free surface is a key challenge in solving these technical problems.

[0004] Based on this, the present invention discloses a method for removing the tetravalent tin oxide layer on the surface of tin niobate without destroying its bulk structure. By applying a negative bias voltage to the electrode, the tetravalent tin layer that shields charge transport is effectively removed, and the electrode surface can be restored to its initial state. The whole method does not destroy the internal crystallinity of the material, nor does it introduce defects into the new surface after treatment, and can form a perfect electrode surface. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a reduction method for removing the tetravalent tin oxide layer on the surface of tin niobate. This method is not only simple, fast, and efficient, but also repeatable and does not damage the bulk structure of tin niobate. In particular, it is suitable for removing tetravalent tin from electrode surfaces over large areas, making it suitable for large-scale promotion and industrial application.

[0006] To achieve the above objectives, the present invention provides a method for removing tetravalent tin from the surface of tin niobate by reduction, comprising immersing a tin niobate electrode material in an electrolyte solution to ensure sufficient contact between the surface of the tin niobate and the electrolyte solution; and applying a bias voltage to the tin niobate electrode material to reduce the tetravalent tin on the surface of the tin niobate, thereby removing the charge shielding layer formed by the tetravalent tin on the surface of the tin niobate.

[0007] Preferably, the tin niobate electrode material is prepared by vapor deposition of tin niobate powder onto the surface of a conductive substrate.

[0008] More preferably, the stannous niobate electrode material is prepared by ion transfer method using 10 μm Ti as a substrate.

[0009] Preferably, the tin niobate film is prepared by growing a thin film on the surface of a conductive substrate.

[0010] Preferably, the pH of the electrolyte solution is 1 to 14.

[0011] Preferably, the electrolyte solution includes, but is not limited to, any one of acid solution, alkaline solution, phosphate buffer solution, and borate buffer solution.

[0012] Preferably, the electrolyte solution includes, but is not limited to, any one of sulfuric acid solution, acetic acid solution, sodium hydroxide solution, potassium hydroxide solution, potassium dihydrogen phosphate / dipotassium hydrogen phosphate buffer solution, and potassium borate buffer solution.

[0013] Preferably, the electrolyte includes, but is not limited to, a sulfuric acid solution with pH=1, an acetic acid / sodium acetate buffer solution with pH=4, a potassium dihydrogen phosphate / dipotassium hydrogen phosphate buffer solution with pH=7, a potassium borate buffer solution with pH=9, and a potassium hydroxide solution with pH=14.

[0014] Preferably, the bias voltage applied to the stannous niobate electrode material is -0.1V to -2V vs. RHE.

[0015] Preferably, the bias voltage is applied for 1 to 30 minutes.

[0016] Preferably, after the reduction reaction is completed, the stannous niobate electrode material is cleaned and then dried with an inert gas.

[0017] The above technical solution, after removing the charge shielding layer formed by tetravalent tin on the surface of the stannous niobate electrode material, is applied in the fields of photocatalysis and photoelectrocatalysis.

[0018] The beneficial technical effects obtained by this invention are as follows: 1. By adopting the technical solution of the present invention, the reduction and dissolution of tetravalent tin on the surface of stannous niobate is effectively regulated by controlling the composition of the electrolyte solution and applying a bias voltage. This reduces the problem of low photovoltage caused by Fermi level pinning due to the presence of tetravalent tin, and also reduces charge recombination at the tetravalent tin sites, thereby achieving the purpose of cleaning the surface and restoring it to its original state.

[0019] 2. The present invention employs a reduction method to treat tetravalent tin on the surface of stannous niobate. After the tetravalent tin is reduced, it combines with -OH to form hydrated tin hydroxide, which dissolves in the solution. Compared with other solutions, the alkalinity is enhanced, and the reduction time required to achieve the same effect is shorter.

[0020] 3. By adopting the technical solution of the present invention, the removal of the tetravalent tin amorphous layer will not damage the stannous niobate crystal and will form a perfect and defect-free surface. In particular, the process can be repeated to restore the stannous niobate to its initial state, thereby greatly saving material costs. Moreover, the removal process is simple, easy to operate, and has low manufacturing costs, providing a technical foundation for future industrialization and application promotion. Attached Figure Description

[0021] Figure 1a This is an HRTEM image of the stannous niobate electrode surface after 1000 s of electrode oxidation, provided in Example 1 of this invention.

[0022] Figure 1b The image shown is an HRTEM image of the stannous niobate semiconductor electrode after reduction, provided in Example 1 of this invention.

[0023] Figure 2a , Figure 2b and Figure 2c The images shown are SEM images of the tin niobate semiconductor electrode, the tin niobate electrode after oxidation for 1000 s, and the electrode after oxidation and reduction, respectively, provided in Example 1 of this invention.

[0024] Figure 2d , Figure 2e , Figure 2f and Figure 2g The images shown are SEM images of the stannous niobate semiconductor electrodes after reduction, provided in Examples 3, 4, 6 and 8 of this invention, respectively.

[0025] Figure 3 This is a graph showing the photocurrent variation of the stannous niobate semiconductor electrode in Embodiment 1 of the present invention under intermittent illumination.

[0026] Figure 4 The photocurrent change diagram of the stannous niobate semiconductor electrode provided in Embodiment 3 of the present invention after five reduction operations.

[0027] Figure 5The photocurrent change diagram of the stannous niobate semiconductor electrode provided in Embodiment 2 of the present invention after three reduction operations.

[0028] Figure 6 Comparison charts showing the surface elemental analysis of the stannous niobate semiconductor electrode provided in Embodiment 3 of the present invention, the stannous niobate semiconductor electrode after reduction under applied bias, the stannous niobate semiconductor electrode after oxidation for 1000 s, and the stannous niobate semiconductor electrode after oxidation for 1000 s followed by reduction. Detailed Implementation

[0029] In view of the deficiencies of the prior art, the present invention provides a method and application for removing tetravalent tin from the surface of stannous niobate by reduction. The specific technical solution of the present invention will be described in detail below through specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. For the sake of concise description, this specification cannot describe all features of the actual embodiments in detail. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that, unless otherwise defined, the technical or scientific terms used in this specification should be known to those skilled in the art described in this application.

[0031] The method for removing tetravalent tin from the surface of tin niobate by reduction provided by the present invention includes immersing a tin niobate electrode material or a tin niobate semiconductor electrode in an electrolyte solution to ensure sufficient contact between the surface of the tin niobate and the electrolyte solution; and applying a bias voltage to the tin niobate electrode material to reduce the tetravalent tin on the surface of the tin niobate, thereby removing the charge shielding layer formed by the tetravalent tin on the surface of the tin niobate.

[0032] In some specific embodiments, the stannous niobate semiconductor electrode is prepared using an ion transfer method on a 10 μm Ti substrate.

[0033] In some specific embodiments, the electrolyte solution includes, but is not limited to, a sulfuric acid solution with pH=1, an acetic acid / sodium acetate buffer solution with pH=4, a potassium dihydrogen phosphate / dipotassium hydrogen phosphate buffer solution with pH=7, a potassium borate buffer solution with pH=9, and a potassium hydroxide solution with pH=14.

[0034] In some specific embodiments, the applied voltage range is -0.1V to -2V vs. RHE.

[0035] In some specific embodiments, the voltage is applied for 1 to 30 minutes.

[0036] The present invention effectively regulates the dissolution of tetravalent tin on the surface of stannous niobate by controlling the composition of the electrolyte solution and the magnitude of the applied bias voltage. This reduces the problem of low photovoltage caused by Fermi level pinning due to the presence of tetravalent tin, and also reduces charge recombination at the tetravalent tin sites, thereby cleaning the surface and restoring it to its original state.

[0037] The technical solution of the present invention will be described in detail below through specific embodiments.

[0038] Example 1 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a sulfuric acid solution with pH 1, and the immersion time is 1 minute.

[0039] 3. Apply a bias voltage of -0.5V vs. RHE to the stannous niobate semiconductor electrode for 2 minutes; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0040] The photoelectric properties of stannous niobate semiconductors were tested.

[0041] See Figure 1a and Figure 1b These are HRTEM images of the stannous niobate semiconductor electrode provided in this embodiment before and after reduction, respectively. Figure 1a As can be seen, the amorphous layer oxidized on the electrode surface is clearly visible before reduction; by Figure 1b It is evident that the amorphous layer of the reduced electrode has been completely removed, indicating that the tetravalent tin amorphous layer on the surface has been removed after reduction.

[0042] Figure 2a , Figure 2b and Figure 2c The images shown are SEM images of the tin niobate semiconductor electrode before oxidation, after oxidation for 1000 seconds, and after oxidation and reduction, respectively. By comparison, it can be seen that the surface of the oxidized electrode is extremely rough due to the formation of a tetravalent tin amorphous layer caused by the oxidation of divalent tin. The surface of the electrode after reduction is relatively smooth, indicating that the tetravalent tin layer has been removed.

[0043] See Figure 3The photocurrent change of the tin niobate semiconductor electrode provided in this embodiment under intermittent illumination was tested three times under the same bias voltage. The photocurrent response after the second illumination was much lower than that after the first illumination. It can be seen that the divalent tin on the surface of the electrode was oxidized to tetravalent and damaged at the moment the light was applied during the first test.

[0044] Combining the HRTEM image and the photocurrent change diagram, it can be seen that after the oxide layer was reduced, the photocurrent returned to the state before oxidation. The high-resolution lattice fringes show that there was no impact on the interior, indicating that the technical solution of this invention only removed the surface oxide layer.

[0045] Example 2 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a boric acid solution with pH 9, and the immersion time is 1 minute.

[0046] 3. Apply a bias voltage of -0.9V vs. RHE to the stannous niobate semiconductor electrode for 4 minutes; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0047] See Figure 5 The figure shows the photocurrent change of the tin niobate semiconductor electrode provided in this embodiment after two reduction operations. After each test, the above operation was repeated to remove the charge shielding layer and then test again. As shown in the figure, 1 is the original state, and 2-3 are the photocurrent magnitudes after two uses and then cleaning. The results show that the electrode surface can be refreshed after each cleaning and will return to the original state.

[0048] Example 3 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a sodium hydroxide buffer solution with pH=14, and the immersion time is 1 minute.

[0049] 3. Apply a bias voltage of -0.4 V vs. RHE to the stannous niobate semiconductor electrode for 6 min; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0050] See Figure 2d The image shows an SEM image of the electrode material surface after reduction by applying a bias voltage in this embodiment. As can be seen from the image, the surface of the reduced electrode material is smoother than that before reduction, indicating that the shielding layer on the surface has been removed.

[0051] See Figure 4 The tin niobate semiconductor electrode provided in this embodiment was used multiple times, and the charge shielding layer was removed by the above reduction method. The photocurrent was then tested. After each test, the above operation was repeated to remove the charge shielding layer and then test again. As shown in the figure, 1 is the original state, and 2-5 are the photocurrent after multiple uses and removal. The results show that the electrode surface can be refreshed (the oxide layer is reduced) after each removal and will return to the original state.

[0052] See Figure 6 The figure shows a comparison of the elemental analysis of the electrode surfaces of the stannous niobate semiconductor electrode (bare electrode), the stannous niobate semiconductor electrode after reduction by applying a bias voltage, the stannous niobate semiconductor electrode after oxidation for 1000 s, and the stannous niobate semiconductor electrode after oxidation for 1000 s followed by reduction. As can be seen from the figure, the elemental analysis of the electrode after oxidation and reduction is consistent with that of the stannous niobate semiconductor electrode (bare electrode), indicating that the electrode surfaces after cleaning can be refreshed back to the original bare electrode state.

[0053] Example 4 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a boric acid solution with pH=9, and the immersion time is 1 minute.

[0054] 3. Apply a bias voltage of -1.5 V vs. RHE to the stannous niobate semiconductor electrode for 1 min; see Figure 2c 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0055] See Figure 2eThe image shows an SEM image of the electrode material surface after reduction by applying a bias voltage in this embodiment. As can be seen from the image, the surface of the reduced electrode material is smoother than that before reduction, indicating that the shielding layer on the surface has been removed.

[0056] Example 5 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a phosphate buffer solution with pH 7, and the immersion time is 1 minute.

[0057] 3. Apply a bias voltage of -0.2 V vs. RHE to the stannous niobate semiconductor electrode for 10 min; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0058] After removing the surface charge shielding layer using the method of this embodiment, the tin niobate semiconductor material is tested by photocurrent. Each time the electrode surface is cleared by reduction, it can be refreshed and returned to its original state.

[0059] Example 6 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution, ensuring complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a potassium hydroxide solution with pH 14, and the immersion time is 1 minute. 3. Apply a bias voltage of -0.3 V vs. RHE to the stannous niobate semiconductor electrode for 5 min; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0060] See Figure 2f The image shows an SEM image of the electrode material surface after reduction by applying a bias voltage in this embodiment. As can be seen from the image, the surface of the reduced electrode material is smoother than that before reduction, indicating that the surface shielding has been removed.

[0061] Example 7 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is an acetic acid / sodium acetate buffer solution with pH=4, and the immersion time is 1 minute.

[0062] 3. Apply a bias voltage of -0.5 V vs. RHE to the stannous niobate semiconductor electrode for 2 min; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0063] After removing the surface charge shielding layer using the method of this embodiment, the tin niobate semiconductor material is tested by photocurrent. Each time the electrode surface is cleared by reduction, it can be refreshed and returned to its original state.

[0064] Example 8 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is an acetate buffer solution with pH=4, and the immersion time is 1 minute.

[0065] 3. Apply a bias voltage of -1.8 V vs. RHE to the stannous niobate semiconductor electrode for 5 min. 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0066] See Figure 2g The image shows an SEM image of the electrode material surface after reduction by applying a bias voltage in this embodiment. As can be seen from the image, the surface of the reduced electrode material is smoother than that before reduction, indicating that the surface shielding has been removed.

[0067] Example 9 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a phosphate / sodium phosphate buffer solution with pH 7, and the immersion time is 1 minute.

[0068] 3. Apply a bias voltage of -1.3 V vs. RHE to the stannous niobate semiconductor electrode for 20 min; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0069] After removing the surface charge shielding layer using the method of this embodiment, the tin niobate semiconductor material is tested by photocurrent. Each time the electrode surface is cleared by reduction, it can be refreshed and returned to its original state.

[0070] Example 9 This embodiment provides a method for removing tetravalent tin from the surface of stannous niobate, the specific steps of which include: 1. A stannous niobate semiconductor electrode is prepared by vapor deposition of stannous niobate powder onto the surface of a substrate material using a particle transfer method. The substrate material is a 10 μm thick Ti. 2. Immerse the stannous niobate semiconductor electrode in the electrolyte solution to ensure complete wetting of the electrode surface and full contact with the electrolyte; the electrolyte solution is a phosphate / sodium phosphate buffer solution with pH=7, and the immersion time is 1 minute.

[0071] 3. Apply a bias voltage of -1.6 V vs. RHE to the stannous niobate semiconductor electrode for 15 min; 4. Remove the stannous niobate semiconductor electrode, rinse it with plenty of water, and then dry it with argon gas.

[0072] After removing the surface charge shielding layer using the method of this embodiment, the tin niobate semiconductor material is tested by photocurrent. Each time the electrode surface is cleared by reduction, it can be refreshed and returned to its original state.

[0073] In addition, the inventors of this case also conducted corresponding experiments using other raw materials and process conditions listed above as alternatives to the various raw materials and corresponding process conditions of the embodiments. The obtained stannous niobate material has high crystallinity and strong photocatalytic activity, and is basically similar to the stannous niobate product prepared in the embodiments.

[0074] The above are merely preferred embodiments of the present invention and do not limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these embodiments within the spirit and principles of the present invention, achieved through conventional substitutions or by achieving the same function without departing from the principles and spirit of the present invention, fall within the scope of protection of the present invention.

Claims

1. A method for removing tetravalent tin from the surface of stannous niobate, characterized in that, This includes immersing a stannous niobate electrode material in an electrolyte solution to ensure that the surface of the stannous niobate electrode material is in full contact with the electrolyte solution; When a bias voltage is applied to the stannous niobate electrode material, the tetravalent tin on the surface of the stannous niobate electrode material undergoes a reduction reaction, combines with -OH to form hydrated tin hydroxide, and dissolves in the electrolyte solution, thereby removing the charge shielding layer on the surface of the stannous niobate electrode material.

2. The method for removing tetravalent tin from the surface of stannous niobate according to claim 1, characterized in that, The stannous niobate electrode material is a photoelectrode prepared by particle transfer; or... The tin niobate film was prepared by growing a thin film of tin niobate on the surface of a conductive substrate.

3. The method for removing tetravalent tin from the surface of stannous niobate according to claim 1, characterized in that, The pH of the electrolyte solution is 1 to 14.

4. The method for removing tetravalent tin from the surface of stannous niobate according to claim 3, characterized in that, The electrolyte solution includes any one of acid solution, alkaline solution, phosphate buffer solution, and borate buffer solution.

5. The method for removing tetravalent tin from the surface of stannous niobate according to claim 3, characterized in that, The electrolyte solution includes any one of sulfuric acid solution, acetic acid solution, sodium hydroxide solution, potassium hydroxide solution, potassium dihydrogen phosphate / dipotassium hydrogen phosphate buffer solution, and potassium borate buffer solution.

6. The method for removing tetravalent tin from the surface of stannous niobate according to claim 1, characterized in that, The bias voltage applied to the stannous niobate electrode material is -0.1V to -2V vs. RHE.

7. The method for removing tetravalent tin from the surface of stannous niobate according to claim 4, characterized in that, The applied bias voltage is applied for 1 to 30 minutes.

8. The method for removing tetravalent tin from the surface of stannous niobate according to claim 1, characterized in that, After the reduction reaction is complete, the stannous niobate electrode material is cleaned and dried with inert gas.

9. The stannous niobate electrode material prepared by the method for removing tetravalent tin from the surface of stannous niobate according to any one of claims 1-8.

10. The application of the stannous niobate electrode material according to claim 9 in the fields of photocatalysis and photoelectrocatalysis.

Images