A monoclinic phase BiVO4 microtube prepared by microwave radiation and its preparation method
Monoclinic BiVO4 microtubes were prepared by combining microwave radiation with polyethylene glycol surfactants and controlling reaction parameters. This solved the problem of the difficulty in mass-producing photocatalytic BiVO4 materials in the existing technology and achieved high-efficiency photocatalytic performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIJING UNIV
- Filing Date
- 2023-01-03
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies make it difficult to easily and massively prepare monoclinic scheelite-structured BiVO4 materials for use in photocatalysis.
Monoclinic BiVO4 microtubes were prepared by using microwave radiation and controlling reaction parameters such as microwave power, frequency, temperature and time, combined with polyethylene glycol as a surfactant.
This method enables the simple and efficient preparation of BiVO4 microtubes with regular morphology and small particle size, thereby improving photocatalytic activity and making them suitable for applications such as pollutant degradation and photoelectrochemical water splitting to produce hydrogen.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of functional materials, and specifically relates to a monoclinic phase BiVO4 microtube prepared by microwave radiation method and its preparation method. Background Technology
[0002] Bismuth vanadate (BiVO4) is an n-type semiconductor material with a narrow band gap, stable function, and high conductivity, and has gradually become a research hotspot in the fields of photochemistry and electrochemistry (G.Zan,T.Wu,h.Chen,etal.BiVO4 nanocoralsuperstructures and their excellent electrical / optical dual-functions[J].Journal of Alloys and Compounds,2021,852:157035). Laboratory-prepared BiVO4 mainly exhibits three crystal structures: monoclinic scheelite, tetragonal scheelite, and tetragonal zircon. The monoclinic scheelite BiVO4 structure contains four unique lattice points: Bi(4e), V(4e), O1(8f), and O2(8f). Bismuth atoms are coordinated by distorted oxygen octahedra, with the closest distance being [missing information]. Meanwhile, the vanadium atom is located at the center of a twisted VO4 tetrahedron. O1 is coordinated with one Bi and one V, and O2 is coordinated with two Bi and one V. Calculations show that Bi(5d 10 6s 2 ), V(3d 0 ) and O(2p 6 The oxidation states of ) are 3 + 5 + and 2 - Such a lattice structure is extremely beneficial to the photocatalytic performance of monoclinic scheelite BiVO4 (A. Walsh, Y. Yan, MNhuda, et al. Band edge electronic structure of BiVO4: elucidating the role of the Bis and Vd orbitals[J]. Chemistry of Materials, 2009, 21(3): 547-551). Currently, there are many methods for synthesizing monoclinic scheelite BiVO4 materials, such as hydrothermal synthesis, chemical precipitation, sol-gel method, spin coating, and electrodeposition method (Wang Lijie. Preparation and photoelectric performance study of bismuth vanadate photocatalysts[D]. Mudanjiang Normal University, 2020). However, exploring a simple preparation method for large-scale preparation of monoclinic scheelite BiVO4 materials for photocatalysis still needs to be studied in detail. Summary of the Invention
[0003] The purpose of this invention is to provide a simple process for the mass production of monoclinic BiVO4 microtubes prepared by microwave irradiation for use in photocatalysis, and a method thereof.
[0004] This invention is implemented using the following scheme:
[0005] A method for preparing monoclinic BiVO4 microtubes by microwave radiation includes the following steps:
[0006] First, at room temperature (25℃), weigh 0.0100–15.0000 g of analytical grade Bi(NO3)3·5H2O and 1.0000–20.0000 g of polyethylene glycol PEG-10000 with a molecular weight of 10000 and place them in a 250 mL beaker. Add 5–150 mL of distilled water, stir evenly, and then sonicate to obtain mixed solution A.
[0007] Second, weigh 0.1000-15.0000g of analytical grade NH4VO3 and place it in a 100mL beaker. Add 30-90mL of distilled water and heat and keep warm to fully dissolve it to obtain a homogeneous solution B.
[0008] Third, pour the mixed solution A obtained in the first step and the homogeneous solution B obtained in the second step into a 500mL quartz round-bottom flask to obtain mixed solution C;
[0009] Fourth, place the mixed solution C obtained in the third step into a microwave reactor with a power of 200-1500W and a frequency of 2450MHz; set the heating temperature to 80-150℃ and the reaction time to 10-200min.
[0010] Fifth, after the reaction is complete, the product is naturally cooled to room temperature (25°C), transferred to a centrifuge, centrifuged, and the precipitate is taken. It is then washed several times with distilled water and ethanol, and dried to obtain monoclinic BiVO4 microtubes.
[0011] Furthermore, in the first step, the solution is stirred clockwise at a uniform speed with a glass rod for 5 to 150 minutes, and then sonicated for 10 to 150 minutes to obtain mixed solution A.
[0012] Furthermore, in the second step, the heating process involves maintaining the temperature in an oven at 60–100°C for 1–5 hours.
[0013] Furthermore, in the fifth step, the product is naturally cooled to room temperature (25°C) and then centrifuged at 2000–8000 rpm for 1–20 minutes, and the precipitate is collected.
[0014] Furthermore, in the fifth step, the drying process involves maintaining the temperature at 0–90°C for 5–48 hours.
[0015] A monoclinic phase BiVO4 microtube was prepared by a microwave radiation method. The microtube has a length of 1.91–10.61 μm and a width of 0.94–2.97 μm.
[0016] A monoclinic BiVO4 microtube was prepared by a microwave irradiation method, and the cell parameters of the product were as follows: α = γ = 90.0° and β = 90.38°, space group I2 / a, where the strongest peak corresponds to the crystal plane indices of...
[0017] Compared with the prior art, the present invention has the following beneficial technical effects:
[0018] The microwave radiation method employed in this invention is simple, energy-concentrated, and allows for large-scale preparation, which is beneficial for improving the synthesis efficiency of BiVO4 materials and reducing the generation of byproducts during the reaction process. The BiVO4 prepared by this invention is a narrow-bandgap, non-toxic n-type semiconductor material with photocatalytic properties, which is widely used in the fields of pollutant degradation, photoelectrochemical water splitting for hydrogen and oxygen production. The monoclinic BiVO4 microtube material prepared by the microwave radiation method of this invention has a regular morphology and small particle size, which increases the active sites of the monoclinic BiVO4 microtube material, thereby improving the photocatalytic activity of the monoclinic BiVO4 microtube, and has profound application value in the field of photocatalysis.
[0019] The microwave radiation process employed is simple to operate, energy-saving and environmentally friendly, with low energy consumption and concentrated energy, which is beneficial to improving the reaction rate and the synthesis efficiency of BiVO4 materials. By changing factors such as the molar ratio of reactants, the amount of surfactant PEG-10000, reaction time, and temperature, the microstructure of the product can be precisely controlled, which is beneficial to obtaining monoclinic phase BiVO4 materials that meet practical needs. The target product, BiVO4 material, has the ability to catalyze the degradation of pollutants and catalyze the photoelectrochemical decomposition of water for energy storage, and is expected to play an important role in the field of photocatalysis.
[0020] The synthesis mechanism of the method of this invention is as follows: Microwave radiation heating has the advantages of being fast, uniform, and without temperature gradients or hysteresis effects. Microwaves, as an energy source, can accelerate the movement and collision of bismuth nitrate and ammonium metavanadate particles in the solution, providing the energy required for thermodynamic crystallization of the reactant molecules and increasing the nucleation rate of the product bismuth vanadate. PEG is a nonionic surfactant whose molecular chains are easily adsorbed on the surface of BiVO4 crystal nuclei, thereby reducing the activity of the initial particles. Furthermore, the adsorption of PEG by the initial crystal nuclei in certain directions can hinder particle growth in the adsorption direction. Therefore, the addition of PEG will change the kinetic deposition process of growth, promoting the anisotropy of crystal nucleus growth. At the same time, the amount of PEG also significantly affects the morphology of the product. If the PEG concentration is less than the CMC, the surfactant cannot form micelles; at this time, the interaction between PEG and the initial BiVO4 crystal nuclei is small and unstable. If excessive PEG is added, exceeding the CMC, supersaturated adsorption will occur, and long-chain macromolecules in the solution system tend to become entangled, increasing the system viscosity and causing particle aggregation. Therefore, under microwave radiation and with specific parameters such as PEG dosage, reactant concentration, and temperature, the method of this invention can controllably synthesize monoclinic BiVO4 microtubes. Attached Figure Description
[0021] Figure 1 X-ray diffraction (XRD) pattern of monoclinic BiVO4 sample with 1g of PEG-10000 added and a reaction time of 110min;
[0022] Figure 2 The crystal structure diagram of monoclinic BiVO4 in sample 14-0688 is shown.
[0023] Figure 3 A 5kx scanning electron microscope (SEM) image of a monoclinic BiVO4 sample with 1g of PEG-10000 added and a reaction time of 110min.
[0024] Figure 4 A 10kx scanning electron microscope (SEM) image of a monoclinic BiVO4 sample with 1g of PEG-10000 added and a reaction time of 110min.
[0025] Figure 5 This is a schematic diagram of the synthesized morphology of the sample;
[0026] Figure 6 X-ray diffraction (XRD) pattern of monoclinic BiVO4 sample with 1g of PEG-10000 added and a reaction time of 130min;
[0027] Figure 7A 5kx scanning electron microscope (SEM) image of a monoclinic BiVO4 sample with 1g of PEG-10000 added and a reaction time of 130min.
[0028] Figure 8 A 10kx scanning electron microscope (SEM) image of a monoclinic BiVO4 sample with 1g of PEG-10000 added and a reaction time of 130min. Detailed Implementation
[0029] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.
[0030] Example 1: Preparation of BiVO4 sample 1 by microwave irradiation method
[0031] At room temperature, 2.0615 g of analytical grade Bi(NO3)3·5H2O and 1 g of polyethylene glycol PEG-10000 with a molecular weight of 10000 were weighed into a 250 mL beaker, and 115 mL of distilled water was added. The mixture was stirred clockwise with a glass rod for 75 min, and then sonicated for 15 min to obtain mixed solution A. Next, 0.7457 g of… NH4VO3 was placed in a 100mL beaker and 85mL of distilled water was added. The solution was kept in an oven at 75℃ for 1h to obtain solution B. Then, mixed solution A and solution B were poured into a 500mL quartz round-bottom flask to obtain mixed solution C. Finally, mixed solution C was placed in a Midea PJ21C-AU microwave reactor, which was modified to have a power of 1000W and a frequency of 2450MHz. An atmospheric pressure reflux cooling device was set up on the microwave reactor and the heating temperature was set to 100℃ and the reaction time to 110min. After the reaction was completed, the quartz round-bottom flask was cooled to room temperature, and the product was transferred to a centrifuge and centrifuged at 8000rpm for 2min. The centrifuged product was taken out, washed 3 times with distilled water, and then washed 3 times with ethanol. The washed product was then placed in an oven and kept at 60℃ for 24h to obtain the target BiVO4 material.
[0032] like Figure 1 As shown, X-ray diffraction results indicate that when the amount of PEG-10000 added is 1g and the reaction time is 110min, the obtained product is pure-phase monoclinic BiVO4. When 2θ = 18.669°, 28.586°, 28.822°, 28.947°, 30.548°, 34.494°, 35.221°, 39.455°, and 46.711°, characteristic peaks consistent with those of monoclinic BiVO4 with standard JCPDS card number No. 14-0688 are observed, and these peaks are consistent with (110). (121), (040), (200), (002) Corresponding to the (240) crystal plane, the cell parameters of the product are: and α = γ = 90.0° and β = 90.38°, space group I2 / a, where the strongest peak corresponds to the (121) crystal plane, the lattice spacing is 0.309 nm, and its crystal structure is as follows. Figure 2 As shown.
[0033] In addition, scanning electron microscope (SEM) images ( Figure 3 , 4 The results show that the obtained product consists of microtubes with a length of 1.91–10.61 μm and a width of 0.98–2.83 μm, as illustrated in the schematic diagram below. Figure 5 As shown, both X-ray diffraction and scanning electron microscopy (SEM) results fully demonstrate that the target product BiVO4 material has a regular morphology and small particle size, making it a functional material with excellent photocatalytic performance.
[0034] Example 2: Preparation of BiVO4 sample 2 by microwave irradiation method
[0035] At room temperature, 2.0615 g of analytical grade Bi(NO3)3·5H2O and 1 g of polyethylene glycol PEG-10000 with a molecular weight of 10000 were weighed into a 250 mL beaker, and 115 mL of distilled water was added. The mixture was stirred clockwise with a glass rod for 75 min, and then sonicated for 15 min to obtain mixed solution A. Next, 0.7457 g of… NH4VO3 was placed in a 100mL beaker and 85mL of distilled water was added. The solution was kept in an oven at 75℃ for 1h to obtain solution B. Then, mixed solution A and solution B were poured into a 500mL quartz round-bottom flask to obtain mixed solution C. Finally, mixed solution C was placed in a Midea PJ21C-AU microwave reactor, which was modified to have a power of 1000W and a frequency of 2450MHz. An atmospheric pressure reflux cooling device was set up on the microwave reactor and the heating temperature was set to 100℃ and the reaction time to 130min. After the reaction was completed, the quartz round-bottom flask was cooled to room temperature, and the product was transferred to a centrifuge and centrifuged at 8000rpm for 2min. The centrifuged product was taken out, washed 3 times with distilled water, and then washed 3 times with ethanol. The washed product was then placed in an oven and kept at 60℃ for 24h to obtain the target BiVO4 material.
[0036] X-ray diffraction results showed that when the amount of PEG-10000 added was 1 g and the reaction time was 130 min, the product obtained was pure-phase monoclinic BiVO4, and its XRD pattern is shown in the figure. Figure 6As shown, when 2θ = 18.988°, 28.822°, 28.947°, 30.548°, 34.494°, 35.221°, 39.455°, 39.545° and 46.711°, there are characteristic peaks that match the monoclinic BiVO4 of standard JCPDS card number No. 14-0688, and are consistent with (011). (121), (040), (200), (002) Corresponding to crystal planes (141) and (240), the cell parameters of the product are: b = 11.701 and α = γ = 90.0° and β = 90.38°, space group I2 / a, where the strongest peak corresponds to the (121) crystal plane, the lattice spacing is 0.309 nm, and its crystal structure is as follows. Figure 2 As shown.
[0037] In addition, scanning electron microscope (SEM) images ( Figure 7 , 8 The results show that the obtained product consists of microtubes with a length of 2.52–8.72 μm and a width of 0.94–2.97 μm, as illustrated in the schematic diagram below. Figure 5 As shown.
[0038] Example 3: Preparation of BiVO4 sample by microwave irradiation method
[0039] At room temperature, 2.0615 g of analytical grade Bi(NO3)3·5H2O and 1 g of polyethylene glycol PEG-10000 with a molecular weight of 10000 were weighed into a 250 mL beaker, and 115 mL of distilled water was added. The mixture was stirred clockwise with a glass rod for 75 min, and then sonicated for 15 min to obtain mixed solution A. Next, 0.7457 g of… NH4VO3 was placed in a 100mL beaker and 85mL of distilled water was added. The solution was kept in an oven at 75℃ for 1h to obtain solution B. Then, mixed solution A and solution B were poured into a 500mL quartz round-bottom flask to obtain mixed solution C. Finally, mixed solution C was placed in a Midea PJ21C-AU microwave reactor, which was modified to have a power of 1000W and a frequency of 2450MHz. An atmospheric pressure reflux cooling device was set up on the microwave reactor and the heating temperature was set to 100℃ and the reaction time to 120min. After the reaction was completed, the quartz round-bottom flask was cooled to room temperature, and the product was transferred to a centrifuge and centrifuged at 8000rpm for 2min. The centrifuged product was taken out, washed 3 times with distilled water, and then washed 3 times with ethanol. The washed product was then placed in an oven and kept at 60℃ for 24h to obtain the target BiVO4 material.
[0040] To demonstrate the effects achieved by the experimental steps used in Examples 1-3 of this invention, the product cannot achieve the expected effects and innovation of Examples 1-3 of this invention if the operations of Examples 1-3 are not used.
[0041] Comparative example of Example 1:
[0042] In (Lin Y, Lu C, Wei C. Microstructure and photocatalytic performance of BiVO4 prepared by hydrothermal method[J]. Journal of Alloys and Compounds, 2019, 781: 56-63), Lin et al. synthesized BiVO4 material using a hydrothermal method as follows: At room temperature, 2.4253 g of Bi(NO3)3·5H2O was first weighed and dissolved in 30 mL of 0.2 mol / L HNO3 solution, and 0.5849 g of… NH4VO3 was dissolved in 30 mL of distilled water; then, the two solutions were stirred with a glass rod for 1 h and mixed evenly; subsequently, the pH of the mixed solution was adjusted to 12 with ammonia and stirred with a glass rod until the solution became a yellow suspension; finally, the suspension was transferred to a high-pressure reactor with a polytetrafluoroethylene liner and heated at 180 °C for 24 h; after the reaction was completed, the product was filtered and washed with distilled water, and dried to obtain the target product BiVO4 material; this method cannot prepare high-purity BiVO4 of a single phase, and the obtained product is a micron rod with a size of 20 μm.
[0043] This invention patent is fundamentally different from the comparative example, and this invention patent has distinct innovation.
[0044] Comparative example of Example 2:
[0045] In (Su J,guo L,Yoriya S, et al. Aqueous growth of pyramidal-shaped BiVO4 nanowire arrays and structural characterization: application to photoelectrochemical Water splitting[J]. Crystal growth & Design, 2009, 10(2): 856-861), Su et al. synthesized BiVO4 material using a hydrothermal method as follows: At room temperature, firstly, 0.9701 g of Bi(NO3)3·5H2O and 0.2340 g of NH4VO3 were weighed and added to 50 mL of 14% hNO3 solution; secondly, the mixture was vigorously stirred and 14.3 g of NH4VO3 was added during the stirring process. NaHCO3; then, the resulting solution was placed on a magnetic stirrer and stirred under reflux at 60°C for 6 hours; finally, the precipitate was separated and washed with deionized water and then dried in a nitrogen environment; after the product was dried, it was annealed in air at 500°C for 0.5 hours to obtain the target product BiVO4 material; this method cannot prepare high-purity BiVO4 of a single phase, and the obtained product is a nanobulk with a size of 50-100 nm.
[0046] This invention patent is fundamentally different from the comparative example, and this invention patent has distinct innovation.
[0047] Comparative example of Example 3:
[0048] In (Ke D, Peng T, Ma L, et al. Photocatalytic Water splitting for O2 production under visible-light irradiation on BiVO4 nanoparticles indifferent sacrificial reagent solutions[J]. Applied Catalysis A:general,2008,350(1):111-117), Ke et al. synthesized BiVO4 material by precipitation as follows: At room temperature, firstly, 2.9100g Bi(NO3)3·5H2O and 0.7204g NH4VO3 were weighed and added to 30mL of 1mol / L HNO3 solution and magnetically stirred for 1h; secondly, 3g of Bi(NO3)3·5H2O and NH4VO3 were weighed and added to 30mL of 1mol / L HNO3 solution and magnetically stirred for 1h; CO(NH2)2 was added to the above mixed solution, and the mixture was stirred evenly with a glass rod. The resulting solution was then heated at 80°C for 24 hours. Subsequently, the product was centrifuged and the precipitate was washed clean with distilled water. Finally, the product was dried at 65°C. After the product was completely dried, it was calcined at 400°C for 3 hours to obtain the target product, BiVO4 material. This method cannot prepare high-purity BiVO4 with a single phase, and the obtained product is nanoparticles with a size of 16.6–36.6 nm.
[0049] This invention patent is fundamentally different from the comparative example, and this invention patent has distinct innovation.
[0050] Example 4: Preparation of BiVO4 sample by microwave irradiation method
[0051] At room temperature (25℃), 0.0100 g of analytical grade Bi(NO3)3·5H2O and 10 g of polyethylene glycol PEG-10000 with a molecular weight of 10000 were weighed into a 250 mL beaker, and 150 mL of distilled water was added. The mixture was stirred clockwise with a glass rod for 5 min, and then sonicated for 150 min to obtain mixed solution A. Next, 0.1000 g of… NH4VO3 was placed in a 100mL beaker and 90mL of distilled water was added. The solution was kept in an oven at 60℃ for 5h to obtain solution B. Then, mixed solution A and solution B were poured into a 500mL quartz round-bottom flask to obtain mixed solution C. Finally, mixed solution C was placed in a Midea PJ21C-AU microwave reactor, which was modified to have a power of 200W and a frequency of 2450MHz. An atmospheric pressure reflux cooling device was set up on the microwave reactor and the heating temperature was set to 150℃ and the reaction time to 200min. After the reaction was completed, the quartz round-bottom flask was cooled to room temperature, and the product was transferred to a centrifuge and centrifuged at 2000rpm for 20min. The centrifuged product was taken out, washed 5 times with distilled water, and then washed 4 times with ethanol. The washed product was then placed in an oven and kept at 50℃ for 48h to obtain the target BiVO4 material.
[0052] Example 5: Preparation of BiVO4 sample by microwave irradiation method
[0053] At room temperature (25℃), 15.0000g of analytical grade Bi(NO3)3·5H2O and 20g of polyethylene glycol PEG-10000 with a molecular weight of 10000 were weighed into a 250mL beaker, and 150mL of distilled water was added. The mixture was stirred clockwise with a glass rod for 150min, and then sonicated for 10min to obtain mixed solution A. Next, 15.0000g of… NH4VO3 was placed in a 100mL beaker and 30mL of distilled water was added. The solution was kept in an oven at 100℃ for 4 hours to obtain solution B. Then, mixed solution A and solution B were poured into a 500mL quartz round-bottom flask to obtain mixed solution C. Finally, mixed solution C was placed in a Midea PJ21C-AU microwave reactor, which was modified to have a power of 1500W and a frequency of 2450MHz. An atmospheric pressure reflux cooling device was set up on the microwave reactor and the heating temperature was set to 80℃ and the reaction time was set to 10min. After the reaction was completed, the quartz round-bottom flask was cooled to room temperature, and the product was transferred to a centrifuge and centrifuged at 5000rpm for 1min. The centrifuged product was taken out, washed 4 times with distilled water, and then washed 5 times with ethanol. The washed product was then placed in an oven and kept at 90℃ for 5 hours to obtain the target BiVO4 material.
Claims
1. A method for preparing monoclinic BiVO4 microtubes by microwave radiation, characterized in that... Includes the following steps: First, at room temperature (25 ℃), weigh 0.0100~15.0000g of analytical grade Bi(NO3)3·5H2O and 1.0000~20.0000g of polyethylene glycol PEG-10000 with a molecular weight of 10000 and place them in a 250mL beaker, add 5~150mL of distilled water, stir evenly, and then sonicate to obtain mixed solution A; Second, weigh 0.1000~15.0000g of analytical grade NH4VO3 and place it in a 100mL beaker. Add 30~90mL of distilled water and heat and keep warm to fully dissolve it to obtain a homogeneous solution B. Third, pour the mixed solution A obtained in the first step and the homogeneous solution B obtained in the second step into a 500mL quartz round-bottom flask to obtain mixed solution C; Fourth, place the mixed solution C obtained in the third step into a microwave reactor with a power of 200~1500W and a frequency of 2450MHz; set the heating temperature to 80~150 ℃ and the reaction time to 10~200min. Fifth, after the reaction is complete, the product is naturally cooled to room temperature (25 °C), transferred to a centrifuge, centrifuged, and the precipitate is taken. It is washed several times with distilled water and ethanol, and dried to obtain monoclinic BiVO4 microtubes. The microtubes have lengths ranging from 1.91 to 10.61 μm and widths ranging from 0.94 to 2.97 μm; the unit cell parameters of the products are a = 5.195 Å, b = 11.701 Å, and c = 5.092 Å, α = γ = 90.0° and β = 90.38°, and the space group is [insert space group here]. I2 / a, where the crystal plane index corresponding to the strongest peak is ( twenty one).
2. The method for preparing a monoclinic phase BiVO4 microtube by microwave radiation according to claim 1, characterized in that: In the first step, the solution is stirred clockwise at a constant speed for 5-150 minutes with a glass rod, and then sonicated for 10-150 minutes to obtain mixed solution A.
3. The method for preparing a monoclinic phase BiVO4 microtube by microwave radiation according to claim 1, characterized in that: The heating process in the second step involves keeping the food at 60~100℃ in an oven for 1~5 hours.
4. The method for preparing a monoclinic phase BiVO4 microtube by microwave radiation according to claim 1, characterized in that: In the fifth step, the product is naturally cooled to room temperature (25°C) and centrifuged in a centrifuge at a speed of 2000-8000 rpm for 1-20 minutes, and the precipitate is collected.
5. The method for preparing a monoclinic phase BiVO4 microtube by microwave radiation according to claim 1, characterized in that: The drying process in the fifth step involves maintaining a temperature of 60-90°C for 5-48 hours.