Process for the preparation of vanadium vacancy-rich vanadate photocatalysts, products and uses thereof

Abstract

The application discloses a preparation method of a vanadium-vacancy-rich vanadate photocatalyst, and a product and application thereof, and belongs to the technical field of photocatalytic materials. The preparation method comprises the following steps: dispersing a vanadate photocatalyst in an alkaline solution for etching treatment, and collecting the vanadium-vacancy-rich vanadate photocatalyst from the product. The preparation method can introduce a large number of vanadium vacancies into the vanadate photocatalyst, form a vanadium gradient etching layer on the surface layer, and meanwhile, retain active metal atoms, so that the charge separation efficiency of the vanadate photocatalyst is effectively improved. Meanwhile, the preparation conditions are easy to control, the equipment requirement is simple, and the industrial production can be realized.

Description

Technical Field

[0001] This application belongs to the field of photocatalytic materials technology, and in particular relates to a method for preparing vanadium vacancy-rich vanadate photocatalysts, their products, and applications. Background Technology

[0002] Vanadate photocatalysts can directly degrade pollutants and convert them into clean energy under sunlight, which is of great significance for controlling environmental pollution and solving energy shortages. However, the low charge separation efficiency of vanadate photocatalysts under visible light greatly restricts their practical application. Therefore, it is necessary to design and develop modification methods to improve the charge separation efficiency of vanadate photocatalysts under visible light.

[0003] Currently, the main technologies for modifying vanadate photocatalysts involve doping and constructing heterojunctions. For example, Gao Xiaoming et al. synthesized Ag-BiVO4 and Co-BiVO4 catalysts with visible light response via a hydrothermal method, achieving improved photocatalytic activity and quantum efficiency; Zhang et al. synthesized ZnFe2O4-BiVO4 heterojunction materials via a one-step chemical coprecipitation method, achieving improved photocatalytic efficiency.

[0004] However, modifying vanadate photocatalysts by doping or constructing heterojunctions has the following problems: First, the types of dopants available are limited, and the dopants are also prone to becoming charge recombination centers, leading to a decrease in charge separation efficiency. Furthermore, the modification process is complex and requires stringent conditions, which is not conducive to industrial production. Second, it can easily cause undirected changes in the crystal structure of vanadate photocatalysts, resulting in poor controllability. Third, it requires the selection of photocatalysts with band gaps that match those of vanadate photocatalysts for composite modification. The number of selectable catalysts is limited, and the construction of composite catalysts has stringent requirements on the size of both catalysts and the synthesis conditions, making large-scale application difficult. Summary of the Invention

[0005] This application discloses a method for preparing vanadium-vacancy-rich vanadate photocatalysts, along with its products and applications, thereby solving the technical problems of complex processes, demanding conditions, significant limitations, and poor controllability in existing doping or composite modification of vanadate photocatalysts.

[0006] To achieve the above objectives, the first aspect of this application provides a method for preparing a vanadium-vacancy-rich vanadate photocatalyst. The preparation method of this application includes the following steps:

[0007] Vanadate photocatalysts are dispersed in an alkaline solution and then etched.

[0008] Collect vanadium vacancy-rich vanadate photocatalysts from the product of the previous step.

[0009] In some embodiments, the vanadate photocatalyst is one of iron vanadate, bismuth vanadate, silver vanadate, zinc vanadate, cadmium vanadate, copper vanadate, or their modified forms or heterojunctions.

[0010] In some embodiments, the alkaline solution is one or a mixture of several of ammonia solution, NaOH solution, KOH solution, and LiOH solution.

[0011] In some embodiments, the solvent for preparing the alkaline solution is one or a mixture of several of water, methanol, ethanol, ethylene glycol, acetone, toluene, and N,N′-dimethylformamide.

[0012] In some embodiments, the concentration of the alkaline solution is 0.01-0.1 mol / L.

[0013] In some implementations, the etching process takes 1-10 minutes.

[0014] In some implementations, the etching process takes 3-8 minutes.

[0015] In some implementations, the etching process takes 6 minutes.

[0016] The second aspect of this application provides a vanadium-vacancy-rich vanadate photocatalyst prepared by the method described in this application.

[0017] The third aspect of this application provides the application of the vanadium vacancy-rich vanadate photocatalyst of this application in photocatalytic degradation, photocatalytic water splitting, and photocatalytic production of hydrogen peroxide.

[0018] Compared with the prior art, the advantages or beneficial effects of the embodiments of this application include at least the following:

[0019] The preparation method provided in this application involves alkaline etching of vanadate photocatalysts, which controllably generates vanadium vacancies on the surface of the vanadate photocatalyst crystal planes and forms a vanadium gradient etched functional layer. Due to the presence of this vanadium gradient etched functional layer, the Fermi level of the etched surface of the vanadate photocatalyst shifts downward, creating an energy level difference with the unetched crystal planes. This imparts a greater charge separation driving force to the prepared vanadium-vacancy-rich vanadate photocatalyst, effectively improving the charge separation efficiency of the vanadate photocatalyst. Furthermore, this preparation method does not introduce exogenous metal ions, is easy to implement, requires simple equipment, is low-cost, and offers good controllability, possessing excellent prospects for industrial production. Moreover, it does not alter the crystal structure of the photocatalyst, thus facilitating the targeted modification of vanadate photocatalysts. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 Photocatalytic water oxidation activity diagrams of vanadium vacancy-rich vanadate photocatalysts etched with different alkaline solutions in embodiments of this application;

[0022] Figure 2 Photocatalytic water oxidation activity diagrams of vanadium-rich vacancy vanadate photocatalysts under different alkaline etching times provided in the embodiments of this application;

[0023] Figure 3 Atomic-resolution annular dark-field scanning transmission electron microscope images of the BiVO4 photocatalyst and the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch1-BiVO4 along the

[001] direction provided in the embodiments of this application.

[0024] Figure 4 Fluorescence intensity test results of BiVO4 photocatalyst and Etch1-BiVO4 photocatalyst rich in vanadium vacancy bismuth vanadate provided in the embodiments of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0027] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0028] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0029] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0030] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood as each intermediate value between the upper and lower limits of the specifically disclosed range. Any stated value or intermediate value within a stated range, as well as any smaller range between any other stated value or intermediate value within said range, are also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] In a first aspect, embodiments of this application provide a method for preparing a vanadium-vacancy-rich vanadate photocatalyst. The preparation method of this application includes:

[0033] Vanadate photocatalysts are dispersed in an alkaline solution and then etched.

[0034] Collect vanadium vacancy-rich vanadate photocatalysts from the product of the previous step.

[0035] Among them, vanadate photocatalysts refer to metal vanadates with photocatalytic activity, including bismuth vanadate (BiVO4), silver vanadate (Ag3VO4), iron vanadate (FeVO4), indium vanadate (InVO4), copper vanadate (CuV2O6), cadmium vanadate (CdV2O6), zinc vanadate (ZnV2O6), etc., prepared by various strategies. In the embodiments of this application, there are no special limitations on the source and preparation strategy of vanadate photocatalysts, and any metal vanadate with photocatalytic activity can be used.

[0036] In this embodiment, collecting vanadium-vacancy-rich vanadate photocatalysts from the product of the previous step includes:

[0037] The product obtained by alkaline etching is then subjected to filtration and drying to obtain a vanadium-vacancy-rich vanadate photocatalyst.

[0038] It should be noted that the filtration separation in this application embodiment can be replaced by various known separation strategies, as long as the vanadium vacancy-rich vanadate photocatalyst that meets the requirements can be separated from the product; the drying treatment is preferably under vacuum conditions, and a reasonable temperature range is selected according to actual needs. This application embodiment will not elaborate on this in detail, as long as the water attached to the vanadium vacancy-rich vanadate photocatalyst is completely removed.

[0039] The preparation method of this application involves alkaline etching of vanadate photocatalysts. This not only controllably generates vanadium vacancies on the surface of the vanadate photocatalyst crystal planes and forms a vanadium gradient etched functional layer, but also selectively exposes active metal atoms such as Bi, Ag, Fe, and Cd. Due to the presence of this vanadium gradient etched functional layer, the Fermi level of the etched crystal planes of the vanadate photocatalyst shifts downward, creating a band difference with the Fermi level of the unetched crystal planes. This imparts a greater charge separation driving force to the prepared vanadium-vacancy-rich vanadate photocatalyst, effectively improving the charge separation efficiency of the vanadate photocatalyst. Furthermore, this preparation process does not introduce exogenous metal ions, is easy to perform, requires simple equipment, is low-cost, and offers good controllability, possessing excellent prospects for industrial production. Moreover, it does not alter the crystal structure of the photocatalyst, thus facilitating the targeted modification of vanadate photocatalysts.

[0040] In a specific embodiment, the vanadate photocatalyst is preferably one of bismuth vanadate (BiVO4), silver vanadate (Ag3VO4), iron vanadate (FeVO4), copper vanadate (CuV2O6), cadmium vanadate (CdV2O6), zinc vanadate (ZnV2O6), or their modified forms or heterojunctions. These vanadate photocatalysts are all visible light photocatalysts with a broad photoresponse range and excellent catalytic activity, enabling better utilization of solar energy and achieving better photoelectrochemical water oxidation capabilities.

[0041] In a specific embodiment, the alkaline solution is one or a mixture of several of ammonia solution, NaOH solution, KOH solution, and LiOH solution. These alkaline solutions are all commonly available, inexpensive, and have easily adjustable alkalinity, making them economically viable and controllable for modifying vanadate photocatalysts.

[0042] To illustrate the effect of different alkaline solutions on the photocatalytic activity of vanadium vacancy-rich vanadate photocatalysts, this application uses BiVO4 photocatalyst as an example. The photocatalytic activity of vanadium vacancy-rich vanadate photocatalysts etched with different alkaline solutions was studied using a single-factor experimental method. The experimental results are as follows: Figure 1 As shown. Among them, Figure 1 Photocatalytic water oxidation activity of vanadium-vacancy-rich BiVO4 photocatalysts modified by etching with different alkaline solutions.

[0043] according to Figure 1 It is evident that, compared to BiVO4 photocatalysts, the photocatalytic water oxidation activity of vanadium-vacancy-rich BiVO4 photocatalysts obtained through etching modification with different alkaline solutions is improved to a certain extent, indicating that alkaline solution etching modification has a promoting effect on the photocatalytic water oxidation activity of vanadium-vacancy-rich vanadate photocatalysts. Furthermore, a comparison of the photocatalytic water oxidation activities of vanadium-vacancy-rich BiVO4 photocatalysts etched with different alkaline solutions shows that the photocatalytic water oxidation activities of vanadium-vacancy-rich vanadate photocatalysts obtained through etching modification with different alkaline solutions vary. NaOH solution etching modification shows the best effect, followed by KOH solution, while LiOH solution etching modification has no significant effect. Therefore, in the embodiments of this application, NaOH solution and KOH solution are preferably used for etching modification.

[0044] In a specific embodiment, the solvent used to prepare the alkaline solution described above is one or a mixture of several of water, methanol, ethanol, ethylene glycol, acetone, toluene, and N,N′-dimethylformamide. These solvents are commonly available, inexpensive, and widely applicable, enabling the uniform and stable dispersion of common vanadate photocatalysts, thus improving the etching effect.

[0045] In a specific embodiment, the concentration of the alkaline solution is preferably 0.01-0.1 mol / L, and can be any concentration selected from 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, or 0.1 mol / L. This concentration of alkaline solution can be used for etching and modification to obtain a vanadium-vacancy-rich vanadate photocatalyst with high photocatalytic activity.

[0046] In a specific embodiment, the etching time is 1-10 min, which can be any time selected from 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, more preferably 3-8 min, and even more preferably 6 min. In this embodiment, controlling the etching time effectively improves the photocatalytic activity of the prepared vanadium-vacancy-rich vanadate photocatalyst.

[0047] To illustrate the effect of etching time on the photocatalytic activity of vanadium vacancy-rich vanadate photocatalysts, this application uses BiVO4 photocatalyst as an example. A single-factor experimental method was used to study the photocatalytic activity of vanadium vacancy-rich vanadate photocatalysts under different alkaline etching times. The experimental results are as follows: Figure 2 As shown. Among them, Figure 2 Photocatalytic water oxidation activity of vanadium-vacancy-rich BiVO4 photocatalysts under different alkaline etching times.

[0048] according to Figure 2 It is evident that within the etching time range of 1-10 min, the prepared vanadium vacancy-rich vanadate photocatalyst exhibits better photocatalytic water oxidation activity compared to vanadate photocatalysts, and this activity first increases and then decreases with increasing etching time. Specifically, within the etching time range of 3-8 min, the photocatalytic water oxidation activity of the vanadium vacancy-rich vanadate photocatalyst further improves, reaching its highest level at an etching time of 6 min. Therefore, the alkaline etching time in this embodiment is further preferably 3-8 min, resulting in a photocatalytic water oxidation activity of over 220 μmol / h for the prepared vanadium vacancy-rich vanadate photocatalyst; and even more preferably 6 min, resulting in a photocatalytic water oxidation activity of over 270 μmol / h for the prepared vanadium vacancy-rich vanadate photocatalyst.

[0049] Secondly, embodiments of this application provide vanadium-vacancy-rich vanadate photocatalysts prepared by the method described in this application. Specifically, embodiments of this application enable the introduction of a large number of vanadium vacancies into the surface layer of the vanadate photocatalyst crystal plane while selectively exposing active metal atoms such as Bi, Ag, Fe, and Cd to form a vanadium gradient etching functional layer. Therefore, the vanadium-vacancy-rich vanadate photocatalysts of this application exhibit superior charge separation efficiency.

[0050] Thirdly, after the embodiments of this application provide the vanadium vacancy-rich vanadate photocatalyst for applications including photocatalytic degradation, photocatalytic water splitting, and photocatalytic production of hydrogen peroxide, the vanadium vacancy-rich vanadate photocatalyst of this application has a more superior charge separation efficiency, thereby significantly improving the conversion efficiency of hydrogen energy and reducing development costs.

[0051] The technical solution of this application will be further described below with reference to specific embodiments.

[0052] Example 1

[0053] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch1-BiVO4, comprising the following steps:

[0054] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.01 mM NaOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch1-BiVO4.

[0055] Example 2

[0056] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch2-BiVO4, comprising the following steps:

[0057] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch2-BiVO4.

[0058] Example 3

[0059] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch3-BiVO4, comprising the following steps:

[0060] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.1 mM NaOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch3-BiVO4.

[0061] Example 4

[0062] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch4-BiVO4, comprising the following steps:

[0063] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 2 min. The powder product was then separated by filtration and collected. The obtained powder product was then washed with water and dried to obtain the vanadium vacancy-rich bismuth vanadate photocatalyst Etch4-BiVO4.

[0064] Example 5

[0065] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch5-BiVO4, comprising the following steps:

[0066] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 4 min. The powder product was then separated by filtration and collected. The obtained powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch6-BiVO4.

[0067] Example 6

[0068] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch6-BiVO4, comprising the following steps:

[0069] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 8 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch6-BiVO4.

[0070] Example 7

[0071] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch7-BiVO4, comprising the following steps:

[0072] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 10 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch7-BiVO4.

[0073] Example 8

[0074] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch8-BiVO4, comprising the following steps:

[0075] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.05 mM LiOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch8-BiVO4.

[0076] Example 9

[0077] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch9-BiVO4, comprising the following steps:

[0078] 100 mg of BiVO4 photocatalyst was dispersed in 100 mL of 0.05 mM KOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch9-BiVO4.

[0079] Example 10

[0080] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch10-FeVO4, comprising the following steps:

[0081] 100 mg of FeVO4 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The obtained powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch10-FeVO4.

[0082] Example 11

[0083] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch11-Ag3VO4, comprising the following steps:

[0084] 100 mg AgVO4 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 6 min. Then, the powder product was separated by filtration and collected. The powder product was washed with water and dried in sequence to obtain the vanadium vacancy bismuth vanadate photocatalyst Etch11-Ag3VO4.

[0085] Example 12

[0086] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch12-ZnV2O6, comprising the following steps:

[0087] 100 mg of ZnV2O6 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 6 min. Then, the powder product was separated by filtration and collected. The powder product was washed with water and dried in sequence to obtain the vanadium vacancy bismuth vanadate photocatalyst Etch12-ZnV2O6.

[0088] Example 13

[0089] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch13-CdV2O6, comprising the following steps:

[0090] 100 mg of CdV2O6 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch13-CdV2O6.

[0091] Example 14

[0092] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch14-CuV2O6, comprising the following steps:

[0093] 100 mg of CuV2O6 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch14-CuV2O6.

[0094] Example 15

[0095] This embodiment provides a method for preparing the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch15-ZnV2O6, comprising the following steps:

[0096] 100 mg of ZnV2O6 photocatalyst was dispersed in 100 mL of 0.05 mM NaOH solution and etched for 6 min. The powder product was then separated by filtration and collected. The powder product was then washed with water and dried to obtain the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch15-ZnV2O6.

[0097] To verify the actual effect of the preparation method in the embodiments of this application, the inventors performed the following morphological and structural characterization and performance characterization:

[0098] First, the vanadium-vacancy-rich bismuth vanadate photocatalysts Etch1-BiVO4 and BiVO4 photocatalysts were subjected to atomic-resolution annular dark-field scanning transmission electron microscopy along the

[001] direction, and the results were as follows: Figure 3As shown. Among them, Figure 3 Atomic-resolution annular dark-field scanning transmission electron microscope images of BiVO4 photocatalyst and Etch1-BiVO4 photocatalyst rich in vanadium vacancy bismuth vanadate along the

[001] direction.

[0099] according to Figure 3 As can be seen, vanadium vacancies are formed on the surface of the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch1-BiVO4 while retaining surface Bi atoms. This indicates that by etching the BiVO4 photocatalyst with an alkaline solution, the V atoms on the BiVO4 surface can be controlled to be etched and the surface Bi atoms exposed. At the same time, the lattice fringe spacing of the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch1-BiVO4, which is etched and modified, does not change, indicating that the modification method in this application does not change the crystal form of vanadate photocatalysts.

[0100] Secondly, the fluorescence intensity of the vanadium-vacancy-rich bismuth vanadate photocatalysts Etch1-BiVO4 and BiVO4 was tested, and the results were as follows: Figure 4 As shown. Among them, Figure 4 The fluorescence intensity test results are for BiVO4 photocatalyst and Etch1-BiVO4 photocatalyst rich in vanadium vacancy bismuth vanadate.

[0101] according to Figure 4 It is evident that, compared to the BiVO4 photocatalyst, the fluorescence intensity of the vanadium-vacancy-rich bismuth vanadate photocatalyst Etch1-BiVO4 is significantly reduced, indicating that the electron and hole separation ability is enhanced. This demonstrates that alkaline etching modification can effectively improve the charge separation efficiency of the BiVO4 photocatalyst.

[0102] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0103] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. The application of vanadium vacancy-rich vanadate photocatalysts in photocatalytic degradation, photocatalytic water splitting, and photocatalytic hydrogen peroxide production, characterized in that, The preparation method of the vanadium vacancy-rich vanadate photocatalyst includes: The vanadate photocatalyst was dispersed in an alkaline solution with a concentration of 0.01 mol / L and etched for 6 min. Collect vanadium vacancy-rich vanadate photocatalysts from the product of the previous step; The vanadate photocatalyst is bismuth vanadate; The alkaline solution is a NaOH solution.

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