Simple preparation method of BiVO4 visible-light-driven photocatalyst
Through the method of aqueous phase precipitation and burning at a specific temperature, the problems of large energy consumption and high equipment cost of traditional hydrothermal method are solved, and low-cost and high-efficiency catalyst preparation is achieved, which is suitable for large-scale production.
Patent Information
- Application Number
- CN202411703530.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-02-28
AI Technical Summary
The existing hydrothermal method of preparing BiVO4 catalysts has problems such as large energy consumption, high equipment costs, and being unfavorable to expanding production scale.
The nano-scale monoclinic syringe tungsten ore-type BiVO4 visible photocatalyst was prepared by controlling the concentration, pH value, reaction temperature, reaction time, burning temperature and time of the reactants.
The equipment cost and energy consumption are reduced, the production scale is enhanced, the preparation process is safe, and the production process is not required to use additional catalysts. The resulting BiVO4 catalyst has good visible photocatalytic effect.
Smart Images
Figure CN119524834A_ABST
Abstract
Description
[Technical field]
[0001] The invention relates to the technical field of photocatalytic materials, and in particular to a simple preparation method of a BiVO4 visible light catalyst. [Background technology]
[0002] The preparation and development of efficient, stable and safe photocatalytic materials is a research hotspot in the fields of materials science, chemistry and environmental science. TiO2 is one of the most widely used photocatalysts, but due to its large bandgap (Eg = 3.2eV), TiO2 can only show catalytic activity under ultraviolet light, and ultraviolet light accounts for less than 5% of the solar spectrum, which limits the use of TiO2 for clean energy such as solar energy. Visible light accounts for as much as 43% of sunlight, so it is of great significance to develop photocatalytic materials with high activity under visible light.
[0003] Among the many new visible light responsive photocatalysts, bismuth vanadate (BiVO4) is a photocatalyst with great potential. BiVO4 of the monoclinic scheelite type has attracted widespread attention due to its narrow bandgap (Eg=2.4eV), strong absorption in the visible light range, good photocatalytic effect, and environmentally friendly characteristics. At present, the preparation method of BiVO4 (monoclinic scheelite type) is mostly hydrothermal method. However, since the hydrothermal method requires a long time of reaction at high temperature, the energy consumption is relatively large; at the same time, the hydrothermal method requires the use of a high temperature and high pressure resistant hydrothermal autoclave as a reaction container, and the reaction needs to be placed in a high temperature box with an explosion-proof door to avoid safety problems. Therefore, the hydrothermal method not only has high energy consumption and high equipment cost, but also has high safety requirements for the synthesis device, which is not conducive to expanding the production scale and also increases the preparation cost of BiVO4. [Summary of the invention]
[0004] The technical problem to be solved by the present invention is to provide a simple preparation method of BiVO4 visible light catalyst, so as to solve the problems of high energy consumption, high preparation cost and disadvantageous for expanding production scale in the existing preparation of BiVO4 by hydrothermal method.
[0005] The present invention is achieved by: a simple preparation method of BiVO4 visible light catalyst, the preparation method comprising the following steps:
[0006] Step S1: dissolve bismuth nitrate [Bi(NO3)3·5H2O] in concentrated nitric acid and add deionized water to a concentration of 0.05 mol·L -1 Bi(NO3)3 solution;
[0007] Step S2: Dissolve ammonium metavanadate (NH4VO3) in hot deionized water to a concentration of 0.05 mol·L -1 NH4VO3 solution;
[0008] Step S3, mixing Bi(NO3)3 solution and NH4VO3 solution at a molar ratio of 1:1, adjusting the pH value to 4, and then stirring the mixture in a 90°C water bath to separate the generated precipitate;
[0009] Step S4, drying the separated precipitate, transferring the dried precipitate to a crucible, and calcining it at 450° C. in a muffle furnace to obtain a BiVO4 visible light catalyst;
[0010] There is no particular order for step S1 and step S2.
[0011] Further, in step S3, the pH value is adjusted to 4 and then heated and stirred in a 90° C. water bath to react as follows:
[0012] The mixed solution was placed in a conical flask, and the pH value of the mixed solution was adjusted to 4 using concentrated ammonia water; the conical flask containing the mixed solution was placed in a water bath, and stirred in a 90°C water bath for 6 hours at a stirring speed of 90-110 rpm.
[0013] Furthermore, the stirring speed is 100 rpm.
[0014] Further, in step S3, the mixing of the Bi(NO3)3 solution and the NH4VO3 solution at a molar ratio of 1:1 is specifically as follows:
[0015] Place the NH4VO3 solution in a conical flask, and while shaking the conical flask, slowly add the same volume of Bi(NO3)3 solution into the conical flask and mix it with the NH4VO3 solution.
[0016] Furthermore, in step S3, the separation of the generated precipitate is specifically: separating the precipitate obtained by the reaction by suction filtration or filtration, and washing the precipitate with deionized water for 6 to 8 times.
[0017] Furthermore, in step S4, the separated precipitate is dried by placing the separated precipitate in an oven and drying it at 80° C. for 1 hour;
[0018] The calcining at 450° C. in a muffle furnace specifically includes: calcining at 450° C. in a muffle furnace for 1 hour.
[0019] Furthermore, in step S4, the obtained BiVO4 visible light photocatalyst is a yellow powder, the crystal phase is a monoclinic scheelite type, and the morphology is aggregated particles.
[0020] Furthermore, in step S2, the temperature of the hot deionized water is 85-95°C.
[0021] The present invention replaces the traditional hydrothermal method to prepare BiVO4 catalyst by water phase precipitation + calcination at a specific temperature, and prepares nano-scale monoclinic scheelite-type BiVO4 visible light catalyst by controlling the concentration of reactants bismuth salt and vanadium salt, pH value of the mixed solution, reaction temperature, reaction time, calcination temperature and calcination time. Compared with the traditional hydrothermal method, the technical solution of the present invention has at least the following significant advantages:
[0022] 1. No complicated and expensive equipment is required, and the requirements for synthesis equipment are low, which can effectively reduce equipment costs and is conducive to expanding production scale.
[0023] 2. There is no need for long-term reaction at high temperature. The preparation process is highly safe, has low energy consumption, and uses cheap raw materials. It can effectively reduce the preparation cost of BiVO4 and is suitable for large-scale production.
[0024] 3. The whole preparation method is very simple and easy to control and operate.
[0025] 4. The entire preparation process does not require the use of additional catalysts, avoiding the possibility of introducing other impurities. The prepared BiVO4 visible light catalyst is a monoclinic scheelite type, which has a good visible light catalytic effect and has no significant difference in catalytic efficiency compared with the sample prepared by the hydrothermal method.
Brief Description of the Drawings
[0026] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.
[0027] Figure 1 is a simplified structural diagram of the synthesis device used in the present invention;
[0028] Figure 2 is a field emission scanning electron microscope image of the BiVO4 visible light photocatalyst obtained in Example 1 of the present invention;
[0029] Figure 3 is an X-ray diffraction (XRD) pattern of the powder of the BiVO4 visible light photocatalyst obtained in Example 1 of the present invention;
[0030] Figure 4 is the UV-Vis diffuse reflectance spectrum of the BiVO4 visible light catalyst obtained in Example 1 of the present invention;
[0031] Figure 5 This is a comparison chart of the degradation rates of the typical environmental pollutant methylene blue (MB) by the BiVO4 visible light photocatalyst obtained in Example 1 of the present invention and the sample prepared by the hydrothermal method (the concentration of the reactants and the pH of the mixed solution are the same, and the water bath heat-burning step in Example 1 is replaced by separating the generated precipitate after hydrothermal reaction at 160°C for 6 hours and then washing and drying).
[0032] Description of reference numerals:
[0033] Bracket 1;
[0034] Water bath 2;
[0035] Agitator 3, stirring blade 31;
[0036] Conical flask 4;
[0037] Fixed clip 5, iron clip 51. [Specific implementation method]
[0038] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.
[0039] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.
[0040] See also Figures 1 to 5 As shown, the present invention provides a simple preparation method of BiVO4 visible light catalyst, the preparation method comprising the following steps:
[0041] Step S1: dissolve bismuth nitrate [Bi(NO3)3·5H2O] in concentrated nitric acid and add deionized water to a concentration of 0.05 mol·L -1 of Bi(NO3)3 solution.
[0042] In the specific implementation of the present invention, the amounts of bismuth nitrate [Bi(NO3)3·5H2O], concentrated nitric acid and deionized water can be weighed and measured according to actual use requirements.
[0043] Step S2: Dissolve ammonium metavanadate (NH4VO3) in hot deionized water to a concentration of 0.05 mol·L -1 NH4VO3 solution; wherein, step S1 and step S2 are in no particular order.
[0044] In the specific implementation of the present invention, the amounts of hot deionized water and ammonium metavanadate (NH4VO3) can be weighed and measured according to actual use requirements.
[0045] In step S2, in order to make ammonium metavanadate (NH4VO3) dissolve better, the temperature of hot deionized water is 85-95°C.
[0046] As a preferred embodiment of the present invention, the temperature of the hot deionized water is 90°C.
[0047] Step S3, mixing Bi(NO3)3 solution and NH4VO3 solution at a molar ratio of 1:1, adjusting the pH value to 4, and then stirring the mixture in a 90°C water bath to separate the generated precipitate (specifically, a yellow precipitate). In the specific implementation of the present invention, the Bi(NO3)3 solution and the NH4VO3 solution can be mixed without waiting for the NH4VO3 solution to cool down.
[0048] In step S3, the pH value is adjusted to 4 and then heated and stirred in a 90° C. water bath to react as follows:
[0049] The pH value of the mixed solution is adjusted to 4 with concentrated ammonia water; the conical flask 4 containing the mixed solution is placed in a water bath 2, and stirred in a 90°C water bath for 6 hours at a stirring speed of 90-110 rpm. As a preferred embodiment of the present invention, the stirring speed is 100 rpm.
[0050] In step S3, the mixing of Bi(NO3)3 solution and NH4VO3 solution at a molar ratio of 1:1 is specifically as follows:
[0051] The NH4VO3 solution is placed in a conical flask 4, and the same volume of Bi(NO3)3 solution is slowly added into the conical flask 4 while shaking the conical flask 4 to mix with the NH4VO3 solution. Since the concentrations of the Bi(NO3)3 solution and the NH4VO3 solution in the present invention are both 0.05 mol·L -1 Therefore, it is only necessary to mix equal volumes of Bi(NO3)3 solution and NH4VO3 solution.
[0052] In the specific implementation of the present invention, a synthesis device can be used to conduct a water bath heat stirring reaction on the mixed solution, such as Figure 1As shown, the synthesis device includes a bracket 1, a water bath 2, a stirrer 3, a conical flask 4 and a fixing clamp 5; one end of the fixing clamp 5 is fixed to the bracket 1, and the other end of the fixing clamp 5 has an iron clamp 51, and the upper end of the conical flask 4 is clamped by the iron clamp 51, so that the conical flask 4 is supported by the iron clamp 5; the stirrer 3 is installed on the bracket 1, and the stirring blade 31 of the stirrer 3 extends into the interior of the conical flask 4, so that the stirrer 3 can drive the stirring blade 31 to rotate to realize automatic stirring of the solution in the conical flask 4; the water bath 2 is located below the conical flask 4, and the middle and lower part of the conical flask 4 is located inside the water bath 2, so that the middle and lower part of the conical flask 4 can be immersed in the hot water of the water bath 2. During specific use, the NH4VO3 solution needs to be placed in the conical flask 4 first, and then the same volume of Bi(NO3)3 solution is slowly added into the conical flask 4 while shaking the conical flask 4 to mix with the NH4VO3 solution, and the pH value of the mixed solution is adjusted to 4 with concentrated ammonia water; then the water in the water bath 2 is heated to 90°C and kept warm, and the middle and lower part of the conical flask 4 is placed in the hot water in the water bath 2, and the water level of the hot water in the water bath 2 is higher than the liquid level of the solution in the conical flask 4; finally, the agitator 3 is used to drive the stirring blades 31 to automatically stir the solution in the conical flask 4, so that the Bi(NO3)3 solution and the NH4VO3 solution can react fully.
[0053] In step S3, the separation of the generated precipitate is specifically: separating the precipitate obtained by the reaction by suction filtration or filtration, and washing the precipitate with deionized water for 6 to 8 times to remove the filtrate. Suction filtration or filtration are both technologies used to separate liquids and solids; filtration relies on gravity to allow liquid to pass through the filter medium, while solid particles are intercepted; suction filtration uses external negative pressure in addition to gravity to allow liquid to pass through the filter medium faster.
[0054] Step S4, drying the separated precipitate, transferring the dried precipitate to a crucible, and calcining it at 450° C. in a muffle furnace to obtain a BiVO4 visible light catalyst.
[0055] In step S4, the step of drying the separated precipitate is as follows: placing the separated precipitate in an oven and drying it at 80° C. for 1 hour;
[0056] The calcining at 450° C. in a muffle furnace specifically includes: calcining at 450° C. in a muffle furnace for 1 hour.
[0057] In step S4, the obtained BiVO4 visible light photocatalyst is yellow powder, the crystal phase is monoclinic scheelite type, the morphology is aggregated particles, and the particle size of the particles is about 200 nm.
[0058] The present invention replaces the traditional hydrothermal method to prepare BiVO4 catalyst by water phase precipitation + calcination at a specific temperature, and prepares nano-scale monoclinic scheelite-type BiVO4 visible light catalyst by controlling the concentration of reactants bismuth salt and vanadium salt, pH value of the mixed solution, reaction temperature, reaction time, calcination temperature and calcination time. Compared with the traditional hydrothermal method, the technical solution of the present invention has at least the following significant advantages:
[0059] 1. No complicated and expensive equipment is required, and the requirements for synthesis equipment are low, which can effectively reduce equipment costs and is conducive to expanding production scale.
[0060] 2. There is no need for long-term reaction at high temperature. The preparation process is highly safe, has low energy consumption, and uses cheap raw materials. It can effectively reduce the preparation cost of BiVO4 and is suitable for large-scale production.
[0061] 3. The whole preparation method is very simple and easy to control and operate.
[0062] 4. The entire preparation process does not require the use of additional catalysts, avoiding the possibility of introducing other impurities. The prepared BiVO4 visible light catalyst is a monoclinic scheelite type, which has a good visible light catalytic effect and has no significant difference in catalytic efficiency compared with the sample prepared by the hydrothermal method.
[0063] The technical solution of the present invention is further described below in conjunction with some specific embodiments:
[0064] Example 1
[0065] Take 2.4254 g of bismuth nitrate [Bi(NO3)3·5H2O], dissolve it in 3 mL of concentrated nitric acid and a small amount of deionized water, and then add deionized water to a volume of 100 mL to prepare a concentration of 0.05 mol·L -1 Heat 100 mL of deionized water to 90°C, dissolve 0.5849 g of ammonium metavanadate (NH4VO3) in hot deionized water to a concentration of 0.05 mol·L -1 NH4VO3 solution. Place the NH4VO3 solution in a conical flask. Without waiting for the NH4VO3 solution to cool, slowly add the Bi(NO3)3 solution to the conical flask and the NH4VO3 solution while shaking the conical flask. After adjusting the pH value of the mixed solution to 4 with concentrated ammonia water, place the conical flask in a water bath and stir at 90°C for 6 hours (stirring speed is 90rpm). After the reaction is completed, filter to obtain a precipitate, wash the precipitate with deionized water 6 times, and discard the filtrate; place the precipitate in an oven and dry it at 80°C for 1 hour (i.e. 1 hour), then transfer the dried precipitate to a crucible and burn it in a muffle furnace at 450°C for 1 hour.
[0066] The photocatalytic efficiency of the prepared BiVO4 visible light photocatalyst was investigated by using methylene blue (MB) solution to simulate industrial wastewater. -1 Place the methylene blue solution in a small beaker, add 0.20g BiVO4 photocatalyst, shake for 5min (i.e. 5 minutes) and then stand in the dark for 12h to allow the sample to be completely adsorbed. Use a 100W incandescent lamp as the light source, and use a filter to allow only visible light with λ≥400nm to pass; the distance between the liquid surface and the light source is 15cm. Take the supernatant every 3h and use a 722 spectrophotometer to detect the absorbance of methylene blue at λ=664nm, and calculate the degradation rate of methylene blue D:
[0067]
[0068] Where, C: methylene blue concentration
[0069] C0: initial concentration of methylene blue
[0070] A: Absorbance of methylene blue
[0071] A0: initial absorbance of methylene blue
[0072] The sample prepared by the hydrothermal method was used as a comparison. The preparation of the hydrothermal reference sample: the preparation, mixing and pH adjustment steps of the reactant solution were the same as those in Example 1, except that the mixed solution was placed in a hydrothermal kettle, and the hydrothermal kettle was placed in a high-temperature oven with an explosion-proof door, and the hydrothermal reaction was carried out at 160°C for 6 hours, filtered, and the precipitate was washed 6 times with deionized water, the filtrate was discarded, and the obtained precipitate was placed in an oven and dried at 80°C for 1 hour.
[0073] like Figure 2 As shown, the Figure 2 This is a field emission scanning electron microscope image of the BiVO4 visible light photocatalyst obtained in Example 1. Figure 2 It can be seen that the morphology of the BiVO4 visible light catalyst is agglomerated particles with a particle size of about 200 nm. Figure 3 As shown, the Figure 3 The X-ray diffraction (XRD) pattern of the powder of BiVO4 visible light photocatalyst obtained in Example 1 is shown in FIG. Figure 3 It can be seen that the diffraction peak corresponds to the monoclinic scheelite type of BiVO4 (PDF card number 14-0688). Figure 4 As shown, the Figure 4 The UV-Vis diffuse reflectance spectrum of the BiVO4 visible light catalyst obtained in Example 1 is shown in FIG. Figure 4 It can be seen that it has absorption in the visible light region, and its bandgap width Eg can be determined to be 2.44eV from the absorption edge of the curve in the figure. Figure 5 As shown, the Figure 5 The degradation rate of the typical environmental pollutant methylene blue (MB) by the BiVO4 visible light photocatalyst obtained in Example 1 and the sample prepared by the hydrothermal method is compared. Figure 5 It can be seen that after 9 hours of visible light irradiation, the degradation rate of methylene blue (MB) by the BiVO4 visible light catalyst obtained in Example 1 is good, and there is no significant difference in catalytic efficiency between the sample prepared by the hydrothermal method and the sample.
[0074] Example 2
[0075] Take 3.6381g of bismuth nitrate [Bi(NO3)3·5H2O], dissolve it in 4.5mL of concentrated nitric acid and a small amount of deionized water, then add deionized water to a volume of 150mL to prepare a concentration of 0.05mol·L -1 Heat 150 mL of deionized water to 90 °C, dissolve 0.8774 g of ammonium metavanadate (NH4VO3) in the hot deionized water to a concentration of 0.05 mol·L -1 NH4VO3 solution. The NH4VO3 solution is placed in a conical flask. Without waiting for the NH4VO3 solution to cool, the Bi(NO3)3 solution is slowly added to the conical flask and the NH4VO3 solution while shaking the conical flask. After the pH value of the mixed solution is adjusted to 4 with concentrated ammonia, the conical flask is placed in a water bath and stirred at 90°C for 6h (stirring speed 100rpm). After the reaction is completed, the precipitate is obtained by suction filtration, and the precipitate is washed with deionized water 7 times, the filtrate is discarded, the precipitate is placed in an oven and dried at 80°C for 1h, and the dried precipitate is transferred to a crucible and burned in a muffle furnace at 450°C for 1h. The morphology of the BiVO4 visible light catalyst obtained in Example 2 is agglomerated particles with a particle size of about 200nm, and its diffraction peak corresponds to the monoclinic scheelite type of BiVO4, and its bandgap width Eg is 2.44eV.
[0076] Example 3
[0077] Take 4.8507g of bismuth nitrate [Bi(NO3)3·5H2O], dissolve it in 6mL of concentrated nitric acid and a small amount of deionized water, then add deionized water to a volume of 200mL to prepare a concentration of 0.05mol·L -1 Heat 200 mL of deionized water to 90 °C, dissolve 1.1698 g of ammonium metavanadate (NH4VO3) in the hot deionized water to a concentration of 0.05 mol·L -1NH4VO3 solution. The NH4VO3 solution is placed in a conical flask. Without waiting for the NH4VO3 solution to cool, the Bi(NO3)3 solution is slowly added to the conical flask and the NH4VO3 solution while shaking the conical flask. After the pH value of the mixed solution is adjusted to 4 with concentrated ammonia, the conical flask is placed in a water bath and stirred at 90°C for 6h (stirring speed 110rpm). After the reaction is completed, the precipitate is obtained by suction filtration, and the precipitate is washed with deionized water 8 times. The filtrate is discarded, and the precipitate is placed in an oven and dried at 80°C for 1h. The dried precipitate is then transferred to a crucible and burned at 450°C in a muffle furnace for 1h. The morphology of the BiVO4 visible light catalyst obtained in Example 3 is agglomerated particles with a particle size of about 200nm, and its diffraction peak corresponds to the monoclinic scheelite type of BiVO4, and its bandgap width Eg is 2.44eV.
[0078] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.
Claims
1. A simple preparation method of BiVO4 visible light catalyst, characterized in that: The preparation method comprises the following steps: Step S1: dissolve bismuth nitrate [Bi(NO3)3·5H2O] in concentrated nitric acid and add deionized water to a concentration of 0.05 mol·L -1 Bi(NO3)3 solution; Step S2: Dissolve ammonium metavanadate (NH4VO3) in hot deionized water to a concentration of 0.05 mol·L -1 NH4VO3 solution; Step S3, mixing Bi(NO3)3 solution and NH4VO3 solution at a molar ratio of 1:1, adjusting the pH value to 4, and then stirring the mixture in a 90°C water bath to separate the generated precipitate; Step S4, drying the separated precipitate, transferring the dried precipitate to a crucible, and calcining it at 450° C. in a muffle furnace to obtain a BiVO4 visible light catalyst; There is no particular order for step S1 and step S2.
2. The simple preparation method of a BiVO4 visible light photocatalyst as claimed in claim 1, characterized in that: In step S3, the pH value is adjusted to 4 and then heated and stirred in a 90° C. water bath to react as follows: The pH value of the mixed solution was adjusted to 4 with concentrated ammonia water; the conical flask containing the mixed solution was placed in a water bath, and the mixture was stirred in a 90° C. water bath for 6 hours at a stirring speed of 90 to 110 rpm.
3. A simple preparation method of a BiVO4 visible light photocatalyst as claimed in claim 2, characterized in that: The stirring speed was 100 rpm.
4. The simple preparation method of a BiVO4 visible light photocatalyst as claimed in claim 1, characterized in that: In step S3, the mixing of Bi(NO3)3 solution and NH4VO3 solution at a molar ratio of 1:1 is specifically as follows: Place the NH4VO3 solution in a conical flask, and while shaking the conical flask, slowly add the same volume of Bi(NO3)3 solution into the conical flask and mix it with the NH4VO3 solution.
5. The simple preparation method of a BiVO4 visible light photocatalyst as claimed in claim 1, characterized in that: In step S3, the separation of the generated precipitate specifically comprises: separating the precipitate obtained by the reaction by suction filtration or filtration, and washing the precipitate with deionized water for 6 to 8 times.
6. The simple preparation method of a BiVO4 visible light photocatalyst as claimed in claim 1, characterized in that: In step S4, the separation of the precipitate is dried by placing the separated precipitate in an oven and drying it at 80° C. for 1 hour; The calcining at 450° C. in a muffle furnace specifically includes: calcining at 450° C. in a muffle furnace for 1 hour.
7. The simple preparation method of a BiVO4 visible light photocatalyst as claimed in claim 1, characterized in that: In step S4, the prepared BiVO4 visible light photocatalyst is a yellow powder, the crystal phase is a monoclinic scheelite type, and the morphology is aggregated particles.
8. The simple preparation method of BiVO4 visible light photocatalyst according to claim 1, characterized in that: In step S2, the temperature of the hot deionized water is 85-95°C.
9. A simple preparation method of a BiVO4 visible light photocatalyst as claimed in claim 8, characterized in that: In step S2, the temperature of the hot deionized water is 90°C.