A Bi2MoO6 / VC / CC composite photoelectrocatalyst and its preparation method and application

Abstract

The invention discloses a Bi2MoO6 / VC / C-C composite photoelectrocatalyst and a preparation method thereof. The preparation method comprises: separately preparing a Bi2MoO6 precursor and VC powder, dispersing the Bi2MoO6 precursor and VC powder in deionized water, adding polyvinyl alcohol to obtain a precursor solution, placing the precursor solution in a crucible and keeping it at 140-180°C for 5-15 minutes, placing a cleaned C-C substrate in the solution and immersing it for 1-10 minutes, removing the C-C substrate, and drying to obtain the desired Bi2MoO6 / VC / C-C photoelectrocatalyst. The Bi2MoO6 / VC / C-C composite photoelectrocatalyst prepared by the invention has effectively improved oxygen evolution efficiency, and the entire preparation process is simple, the conditions are easily controllable, the production cost is low, and it is easy to industrialize production. The prepared product has high purity and good crystallinity.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials and relates to photoelectrocatalytic materials, and specifically to a Bi2MoO6 / VC / CC composite photoelectrocatalyst and its preparation method and application. Background Art

[0002] Energy is one of the greatest challenges facing human society today, and developing clean, sustainable new energy sources is an effective strategy to address this issue. Currently, the full development and utilization of solar energy is becoming a growing research trend in energy utilization. Photoelectrochemical (PEC) water splitting, which converts solar energy into hydrogen (H2), is a highly promising solar energy utilization strategy. This approach converts solar energy into equally clean and sustainable hydrogen energy for storage and utilization. A complete PEC system consists of a photocathode, a photoanode, and an electrolyte. To achieve an efficient PEC water splitting system, it is necessary to develop stable, efficient, and inexpensive electrode materials to achieve high solar-to-hydrogen conversion efficiency. During the operation of a PEC water splitting system, the efficiency of light absorption, charge transport, and interfacial charge transfer jointly determine the performance of the device. Currently developed electrode materials still suffer from low light absorption, severe charge recombination, and slow reaction kinetics. To address these issues, it is necessary to develop high-quality semiconductor materials and further optimize them through strategies such as morphology manipulation, doping, and heterojunction construction to achieve efficient and stable photoelectrochemical water splitting for hydrogen and oxygen production.

[0003] Bismuth molybdate (Bi2MoO6) is made of MoO4 2- With Bi2O2 2+ Layered Aurivillius compounds formed by alternating stacking. The built-in electric field is composed of MoO4 2- With Bi2O2 2+The heterogeneous charge polarization between the two species is beneficial to improve the separation efficiency of photogenerated carriers. Bi2MoO6 shows great potential in the field of visible-light-driven photocatalysis due to its narrow band gap, high stability and environmental friendliness. However, bismuth-based catalysts also have some disadvantages, such as small specific surface area, long migration distance of photogenerated carriers and high possibility of bulk recombination. In order to further enhance the performance of Bi2MoO6 PEC, people have made considerable efforts on various chemical modifications (such as doping) and heterostructures. However, nanoengineering provides us with a completely different approach to improve PEC performance by adjusting intrinsic electrochemical processes such as surface reactions and charge separation / migration. Transition metal carbides (TMCs) are a member of many catalysts composed of non-noble transition metals. Since 1973, they have been famous for their "Pt-like behavior". Mo2C and W2C are typical representatives of TMCs and have been widely studied as efficient and promising HER electrocatalysts. Compared to the former, VB group metal carbides, especially vanadium carbide (VC), have attracted extensive attention due to their high natural abundance, low cost, and low density. However, the electrocatalytic activity of VC remains unsatisfactory due to inappropriate interactions between the surface and reaction intermediates. Therefore, it is necessary to tune its catalytic performance through surface modification and defect engineering. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a Bi2MoO6 / VC / CC composite photoelectrocatalyst and its preparation method and application. The photoelectrocatalyst is a composite photoelectrocatalytic material composed of Bi2MoO6 and VC deposited on a CC substrate after compounding. The heterogeneous structure formed after the thin nanosheet structure of Bi2MoO6 and VC is compounded increases the range of light absorption and enhances the transfer of electrons. The surface of the CC substrate is loose and porous. After compounding, the oxygen evolution efficiency of the Bi2MoO6 / VC / CC composite photoelectrocatalyst is effectively improved.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a Bi2MoO6 / VC / CC composite photoelectrocatalyst comprises the following steps:

[0007] Step 1: Sodium molybdate dihydrate and bismuth nitrate pentahydrate powders are prepared in a mass ratio of 1: (1-3), mixed evenly, placed in a white magnetic boat, placed in a tube furnace, and heated from room temperature to 500-700°C at a rate of 5-20°C / min under the protection of an inert atmosphere of Ar. The temperature is kept at this temperature for 2-4 hours. After the product is cooled, it is taken out, ground, centrifuged, washed, and dried to obtain a Bi2MoO6 precursor.

[0008] Step 2: ammonium metavanadate, dicyandiamide, and urea are mixed in a mass ratio of 1: (0.5-4): (1-5), placed in a white magnetic boat, and placed in a tube furnace. Under the protection of an inert atmosphere of Ar, the temperature is increased from room temperature to 800-1000°C at a rate of 5-20°C / min, and the temperature is kept for 2-4 hours. After the product is cooled, it is taken out and ground to obtain VC powder;

[0009] Step 3: Take 0.3-0.6 g of Bi2MoO6 powder prepared in step 1 and VC powder prepared in step 2 and place them in the same beaker, add 30-50 mL of deionized water, stir until uniformly dispersed, then add 0.005-0.02 g of polyvinyl alcohol, continue stirring until uniformly dispersed, obtain a precursor solution and transfer it to a crucible;

[0010] Step 4: Set the working temperature of the muffle furnace to 140-180°C. When the temperature inside the muffle furnace reaches the set temperature, place the crucible containing the precursor solution in the muffle furnace and keep it warm for 5-15 minutes. Then, use crucible tongs to take it out, place the cleaned CC substrate in the solution and immerse it for 1-10 minutes. Take out the CC substrate and dry it to obtain the required Bi2MoO6 / VC / CC photoelectrocatalyst.

[0011] The present invention also has the following technical features:

[0012] Preferably, the grinding in step 1 and step 2 is performed using a mortar for 40 to 120 minutes.

[0013] Preferably, the centrifugal washing in step 1 is to transfer the product to a centrifuge tube, centrifuge at 8000-12000 r / min for 5-15 minutes to separate the solid, and rinse with deionized water and anhydrous ethanol alternately for 3-5 times.

[0014] Preferably, the drying in step 1 and step 4 is to place the product in a vacuum drying oven at 80° C. and dry it for 8 to 16 hours.

[0015] Preferably, the stirring time in step 3 is 5 to 10 minutes, and the stirring rate is 500 to 700 r / min.

[0016] Preferably, the CC substrate in step 4 is cleaned by placing the substrate in a beaker and performing alternating ultrasonic cleaning with water and alcohol for 20 minutes.

[0017] The present invention also protects a Bi2MoO6 / VC / CC composite photoelectrocatalyst prepared by the method as described above and its use as a photoanode in photocatalytic water electrolysis.

[0018] Compared with the prior art, the present invention has the following technical effects:

[0019] In the process of preparing Bi2MoO6 / VC / CC photoelectrocatalytic materials, the present invention combines a solid-phase sintering method with a hot impregnation method. The required raw materials are first mixed and synthesized through a simple solid-phase sintering process, and then the composite photoelectrocatalytic material is obtained through a one-step impregnation process. The entire preparation process is simple, the conditions are easy to control, the production cost is low, and it is easy to industrialize production. The prepared product has high purity and good crystallinity.

[0020] The Bi2MoO6 / VC / CC photoelectrocatalyst prepared by the present invention is a composite photoelectrocatalytic material composed of Bi2MoO6 and VC deposited on a CC substrate after compounding. The thin nanosheet structure of Bi2MoO6 is compounded with VC to construct a heterojunction with strong electronic interaction at the two-phase heterogeneous interface, which increases the range of light absorption, enhances electron transfer, and can improve the overall conductivity, adsorption energy and reaction kinetics. The surface of the CC substrate is loose and porous, and can present more active sites to effectively promote the separation and transmission of photogenerated charges. After compounding, the oxygen evolution efficiency of the Bi2MoO6 / VC / CC composite photoelectrocatalyst is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the X-ray diffraction analysis diagram of Bi2MoO6 prepared in Example 2;

[0022] Figure 2 This is the X-ray diffraction analysis pattern of VC prepared in Example 2;

[0023] Figure 3 This is a scanning electron microscope image of the Bi2MoO6 / VC / CC photoelectrocatalyst prepared in Example 2 at 5 μm;

[0024] Figure 4 This is the oxygen evolution performance diagram of Bi2MoO6 / VC / CC prepared in Example 2 in a solution with a pH of 9.5. DETAILED DESCRIPTION

[0025] The specific contents of the present invention are further explained in detail below with reference to the embodiments.

[0026] The reagents, methods, and equipment used in the present invention are conventional in the art. The experimental methods in the following examples, where specific experimental conditions are not specified, generally follow conventional experimental conditions. Unless otherwise specified, the reagents and raw materials used in the present invention are commercially available.

[0027] In the following examples, the CC substrate was cleaned by placing the substrate in a beaker and ultrasonically cleaning it with water and alcohol alternately for 20 minutes.

[0028] Example 1

[0029] Step 1, sodium molybdate dihydrate and bismuth nitrate pentahydrate powder are prepared in a mass ratio of 1:1, ground with a mortar for 5 minutes until the mixture is evenly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and under the protection of an inert atmosphere of Ar, heated to 500°C at a rate of 5°C / min, kept warm for 4 hours, and after the product is cooled, taken out and transferred to a centrifuge tube, centrifuged at 8000r / min for 15 minutes, rinsed alternately with deionized water and anhydrous ethanol three times, and after removing the supernatant, a precipitate is obtained. The product is placed in a vacuum drying oven at 80°C and dried for 8 hours, taken out and ground with a mortar for 40 minutes to obtain a Bi2MoO6 precursor;

[0030] Step 2: ammonium metavanadate, dicyandiamide, and urea are mixed in a mass ratio of 1:0.5:1, ground in a mortar for 5 minutes until the mixture is uniformly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and heated to 800°C at a rate of 5°C / min under the protection of an inert atmosphere of Ar. The temperature is kept at 4 hours, and after the product is cooled, it is taken out and ground in a mortar for 40 minutes to obtain VC powder;

[0031] Step 3: Take 0.3g of Bi2MoO6 powder prepared in step 1 and VC powder prepared in step 2 and place them in the same beaker, add 30mL of deionized water, stir for 10min at a stirring rate of 500r / min, then add 0.005g of polyvinyl alcohol (PVA) and continue stirring for 5min until uniformly dispersed to obtain precursor solution B, and transfer solution B to a crucible;

[0032] Step 4: Set the working temperature of the muffle furnace to 140°C. After the temperature inside the muffle furnace rises to the set temperature, place the crucible in the muffle furnace and keep it warm for 15 minutes. Then, use crucible tongs to take it out. Then, turn off the equipment. Place the cleaned CC substrate in the solution and immerse it for 10 minutes. Take out the CC substrate and place it in a vacuum drying oven at 80°C for 8 hours. Then, the required Bi2MoO6 / VC / CC photoelectrocatalyst can be obtained.

[0033] The photoelectrocatalytic effect of Bi2MoO6 / VC / CC was tested using a chi660e device. The test involved cutting the composite photoelectrocatalyst into pieces 1 x 1.5 cm in size and placing them in a sodium tetraborate solution with a pH of 9.5 for the photoelectrochemical oxygen evolution test.

[0034] Example 2:

[0035] Step 1, sodium molybdate dihydrate and bismuth nitrate pentahydrate powder are prepared in a mass ratio of 1:2, ground with a mortar for 5 minutes until the mixture is evenly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and under the protection of an inert atmosphere of Ar, heated to 600°C at a rate of 10°C / min, kept warm for 3 hours, and after the product is cooled, taken out and transferred to a centrifuge tube, centrifuged at 8000r / min for 5 minutes, rinsed alternately with deionized water and anhydrous ethanol three times, and after removing the supernatant, a precipitate is obtained. The product is placed in a vacuum drying oven at 80°C for 12 hours, taken out and ground with a mortar for 80 minutes to obtain a Bi2MoO6 precursor;

[0036] Step 2: ammonium metavanadate, dicyandiamide, and urea are mixed in a mass ratio of 1:2:3, ground in a mortar for 5 minutes until the mixture is uniformly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and under the protection of an inert atmosphere of Ar, heated to 900°C at a rate of 10°C / min and kept warm for 3 hours. After the product is cooled, it is taken out and ground in a mortar for 80 minutes to obtain VC powder;

[0037] Step 3: Take 0.45g of Bi2MoO6 powder prepared in step 1 and VC powder prepared in step 2 and place them in the same beaker, add 40mL of deionized water, stir for 5min at a stirring rate of 700r / min, then add 0.01g of polyvinyl alcohol (PVA) and continue stirring for 10min until uniformly dispersed to obtain precursor solution B, and transfer solution B to a crucible;

[0038] Step 4: Set the working temperature of the muffle furnace to 160°C. After the temperature inside the muffle furnace rises to the set temperature, place the crucible in the muffle furnace and keep it warm for 10 minutes. Then, use crucible tongs to take it out. Then, turn off the equipment. Place the cleaned CC substrate in the solution and immerse it for 5 minutes. Then take out the CC substrate and place it in a vacuum drying oven at 80°C for 12 hours. Then, the required Bi2MoO6 / VC / CC photoelectrocatalyst can be obtained.

[0039] The photoelectrocatalytic effect of Bi2MoO6 / VC / CC was tested using a chi660e device. The test involved cutting the composite photoelectrocatalyst into pieces 1 x 1.5 cm in size and placing them in a sodium tetraborate solution with a pH of 9.5 for the photoelectrochemical oxygen evolution test.

[0040] Figure 1 This is the X-ray diffraction analysis diagram of Bi2MoO6 prepared in Example 2, where the horizontal axis is the 2θ angle and the vertical axis is the diffraction peak intensity. The Bi2MoO6 can also accurately correspond to the Bi2MoO6 PDF#76-2388 card, indicating that the Bi2MoO6 powder was successfully prepared;

[0041] Figure 2 This is the X-ray diffraction analysis diagram of VC prepared in Example 2, where the horizontal axis is the 2θ angle and the vertical axis is the diffraction peak intensity. At the same time, VC can accurately correspond to the VC PDF#73-0476 card, indicating that VC powder was successfully prepared;

[0042] Figure 3 This is a scanning electron microscope image of the Bi2MoO6 / VC / CC photoelectrocatalyst prepared in Example 2 at 5 μm. 6 / VC powder was successfully deposited on the CC substrate;

[0043] Figure 4 This is the oxygen evolution performance diagram of Bi2MoO6 / VC / CC prepared in Example 2 in a solution with a pH of 9.5. The composite photoelectrocatalyst exhibits a current of 4.2 mA / cm at 1.23 V. 2 overpotential.

[0044] Example 3:

[0045] Step 1, sodium molybdate dihydrate and bismuth nitrate pentahydrate powder are prepared in a mass ratio of 1:3, ground with a mortar for 5 minutes until the mixture is evenly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and under the protection of an inert atmosphere of Ar, heated to 700°C at a rate of 20°C / min, kept warm for 2 hours, and after the product is cooled, taken out and transferred to a centrifuge tube, centrifuged at 12000r / min for 5 minutes, rinsed alternately with deionized water and anhydrous ethanol three times, and after removing the supernatant, a precipitate is obtained. The product is placed in a vacuum drying oven at 80°C for 16 hours, taken out and ground with a mortar for 120 minutes to obtain a Bi2MoO6 precursor;

[0046] Step 2: ammonium metavanadate, dicyandiamide, and urea are mixed in a mass ratio of 1:4:5, ground in a mortar for 5 minutes until the mixture is uniformly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and heated at a rate of 20°C / min to 1000°C under the protection of an inert atmosphere of Ar. The temperature is kept at this temperature for 2 hours. After the product is cooled, it is taken out and ground in a mortar for 120 minutes to obtain VC powder.

[0047] Step 3: Take 0.6g of Bi2MoO6 powder prepared in step 1 and VC powder prepared in step 2 and place them in the same beaker, add 50mL of deionized water, stir for 8min at a stirring rate of 600r / min, then add 0.02g of polyvinyl alcohol (PVA) and continue stirring for 8min until uniformly dispersed to obtain precursor solution B, and transfer solution B to a crucible;

[0048] Step 4: Set the working temperature of the muffle furnace to 180°C. When the temperature inside the muffle furnace rises to the set temperature, place the crucible in the muffle furnace and keep it warm for 5 minutes. Then, use crucible tongs to take it out. Then, turn off the equipment. Place the cleaned CC substrate in the solution and immerse it for 1 minute. Take out the CC substrate and place it in a vacuum drying oven at 80°C for 16 hours. Then, the required Bi2MoO6 / VC / CC photoelectrocatalyst can be obtained.

[0049] The photoelectrocatalytic effect of Bi2MoO6 / VC / CC was tested using a chi660e device. The test involved cutting the composite photoelectrocatalyst into pieces 1 x 1.5 cm in size and placing them in a sodium tetraborate solution with a pH of 9.5 for the photoelectrochemical oxygen evolution test.

[0050] Example 4:

[0051] Step 1, sodium molybdate dihydrate and bismuth nitrate pentahydrate powder are prepared in a mass ratio of 1:1.5, ground with a mortar for 5 minutes until mixed evenly to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and under the protection of an inert atmosphere of Ar, heated to 700°C at a rate of 15°C / min, kept warm for 2 hours, and after the product is cooled, taken out and transferred to a centrifuge tube, centrifuged at 12000r / min for 5 minutes, rinsed alternately with deionized water and anhydrous ethanol three times, and after removing the supernatant, a precipitate is obtained. The product is placed in a vacuum drying oven at 80°C and dried for 16 hours, taken out and ground with a mortar for 120 minutes to obtain a Bi2MoO6 precursor;

[0052] Step 2: ammonium metavanadate, dicyandiamide, and urea are mixed in a mass ratio of 1:0.5:5, ground in a mortar for 5 minutes until the mixture is uniformly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and heated to 1000°C at a rate of 20°C / min under the protection of an inert atmosphere of Ar. The temperature is kept at 1000°C for 2 hours. After the product is cooled, it is taken out and ground in a mortar for 120 minutes to obtain VC powder;

[0053] Step 3: Take 0.6g of Bi2MoO6 powder prepared in step 1 and VC powder prepared in step 2 and place them in the same beaker, add 50mL of deionized water, stir for 8min at a stirring rate of 600r / min, then add 0.02g of polyvinyl alcohol (PVA) and continue stirring for 8min until uniformly dispersed to obtain precursor solution B, and transfer solution B to a crucible;

[0054] Step 4: Set the working temperature of the muffle furnace to 180°C. When the temperature inside the muffle furnace rises to the set temperature, place the crucible in the muffle furnace and keep it warm for 5 minutes. Then, use crucible tongs to take it out. Then, turn off the equipment. Place the cleaned CC substrate in the solution and immerse it for 1 minute. Take out the CC substrate and place it in a vacuum drying oven at 80°C for 16 hours. Then, the required Bi2MoO6 / VC / CC photoelectrocatalyst can be obtained.

[0055] The photoelectrocatalytic effect of Bi2MoO6 / VC / CC was tested using a chi660e device. The test involved cutting the composite photoelectrocatalyst into pieces 1 x 1.5 cm in size and placing them in a sodium tetraborate solution with a pH of 9.5 for the photoelectrochemical oxygen evolution test.

[0056] Example 5:

[0057] Step 1, sodium molybdate dihydrate and bismuth nitrate pentahydrate powder are prepared in a mass ratio of 1:2.5, ground with a mortar for 5 minutes until the mixture is uniformly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and under the protection of an inert atmosphere of Ar, heated to 700°C at a rate of 20°C / min, kept warm for 2 hours, and after the product is cooled, taken out and transferred to a centrifuge tube, centrifuged at 12000r / min for 5 minutes, rinsed alternately with deionized water and anhydrous ethanol three times, and after removing the supernatant, a precipitate is obtained. The product is placed in a vacuum drying oven at 80°C for 16 hours, taken out and ground with a mortar for 120 minutes to obtain a Bi2MoO6 precursor;

[0058] Step 2: ammonium metavanadate, dicyandiamide, and urea are mixed in a mass ratio of 1:4:1, ground in a mortar for 5 minutes until the mixture is uniformly mixed to obtain a mixed powder, placed in a white magnetic boat, placed in a tube furnace, and heated to 1000°C at a rate of 20°C / min under the protection of an inert atmosphere of Ar. The temperature is kept at 1000°C for 2 hours. After the product is cooled, it is taken out and ground in a mortar for 120 minutes to obtain VC powder;

[0059] Step 3: Take 0.5g of Bi2MoO6 powder prepared in step 1 and VC powder prepared in step 2 and place them in the same beaker, add 50mL of deionized water, stir for 8min at a stirring rate of 600r / min, then add 0.02g of polyvinyl alcohol (PVA) and continue stirring for 8min until uniformly dispersed to obtain precursor solution B, and transfer solution B to a crucible;

[0060] Step 4: Set the working temperature of the muffle furnace to 180°C. When the temperature inside the muffle furnace rises to the set temperature, place the crucible in the muffle furnace and keep it warm for 5 minutes. Then, use crucible tongs to take it out. Then, turn off the equipment. Place the cleaned CC substrate in the solution and immerse it for 1 minute. Take out the CC substrate and place it in a vacuum drying oven at 80°C for 16 hours. Then, the required Bi2MoO6 / VC / CC photoelectrocatalyst can be obtained.

[0061] The photoelectrocatalytic effect of Bi2MoO6 / VC / CC was tested using a chi660e device. The test involved cutting the composite photoelectrocatalyst into pieces 1 x 1.5 cm in size and placing them in a sodium tetraborate solution with a pH of 9.5 for the photoelectrochemical oxygen evolution test.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it; without departing from the concept of the present invention, the deduction or replacement made by those skilled in the art shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a Bi2MoO6 / VC / CC composite photoelectrocatalyst, characterized in that: The following steps are involved: Step 1: Sodium molybdate dihydrate and bismuth nitrate pentahydrate powder are prepared in a mass ratio of 1: (1-3), mixed evenly, and placed in a white porcelain boat. The mixture is then placed in a tube furnace. Under the protection of an inert atmosphere of Ar, the temperature is raised from room temperature to 500-700°C at a rate of 5-20°C / min, and the temperature is kept for 2-4 hours. After the product is cooled, it is taken out, centrifuged, washed, dried, and then ground to obtain a Bi2MoO6 precursor. Step 2: ammonium metavanadate, dicyandiamide, and urea are mixed in a mass ratio of 1: (0.5-4): (1-5), placed in a white porcelain boat, and placed in a tube furnace. Under the protection of an inert atmosphere of Ar, the temperature is increased from room temperature to 800-1000°C at a rate of 5-20°C / min, and the temperature is kept for 2-4 hours. After the product is cooled, it is taken out and ground to obtain VC powder; Step 3: Take 0.3-0.6 g of Bi2MoO6 powder prepared in step 1 and VC powder prepared in step 2 and place them in the same beaker, add 30-50 mL of deionized water, stir until uniformly dispersed, then add 0.005-0.02 g of polyvinyl alcohol, continue stirring until uniformly dispersed, obtain a precursor solution and transfer it to a crucible; Step 4: Set the working temperature of the muffle furnace to 140-180°C. When the temperature inside the muffle furnace reaches the set temperature, place the crucible containing the precursor solution in the muffle furnace and keep it warm for 5-15 minutes. Then, use crucible tongs to take it out, place the cleaned CC substrate in the solution and immerse it for 1-10 minutes. Take out the CC substrate and dry it to obtain the required Bi2MoO6 / VC / CC photoelectrocatalyst.

2. The method for preparing the Bi2MoO6 / VC / CC composite photoelectrocatalyst according to claim 1, wherein: The grinding described in step 1 and step 2 is performed by grinding in a mortar for 40 to 120 minutes.

3. The method for preparing the Bi2MoO6 / VC / CC composite photoelectrocatalyst according to claim 1, wherein: The centrifugal washing in step 1 is to transfer the product to a centrifuge tube, centrifuge at 8000-12000 r / min for 5-15 minutes to separate the solid, and then rinse with deionized water and anhydrous ethanol alternately for 3-5 times.

4. The method for preparing the Bi2MoO6 / VC / CC composite photoelectrocatalyst according to claim 1, wherein: The drying in step 1 and step 4 is to place the product in a vacuum drying oven at 80° C. and dry it for 8 to 16 hours.

5. The method for preparing the Bi2MoO6 / VC / CC composite photoelectrocatalyst according to claim 1, wherein: The stirring time in step 3 is 5 to 10 minutes, and the stirring rate is 500 to 700 r / min.

6. The method for preparing the Bi2MoO6 / VC / CC composite photoelectrocatalyst according to claim 1, wherein: The CC substrate described in step 4 is cleaned by placing the substrate in a beaker and ultrasonically cleaning it alternately with water and alcohol for 20 minutes.

7. A Bi2MoO6 / VC / CC composite photoelectrocatalyst prepared by the method according to any one of claims 1 to 6.

8. Use of the Bi2MoO6 / VC / CC composite photoelectrocatalyst as claimed in claim 7 as a photoanode in photocatalytic water electrolysis.

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