CTAB (Cetyltrimethyl Ammonium Bromide) modified bismuth silicate / molybdenum carbide / carbon-carbon composite material photoelectrocatalytic coating material and preparation method thereof

Abstract

The invention discloses a CTAB (Cetyltrimethyl Ammonium Bromide) modified bismuth silicate / molybdenum carbide / carbon-carbon composite material photoelectrocatalysis coating material and a preparation method, and belongs to the field of photoelectrocatalysis coating materials.The preparation method comprises the following steps: adjusting the pH value of a mixed solution of bismuth nitrate pentahydrate, sodium silicate nonahydrate and hexadecyl trimethyl ammonium bromide to 7-14 to obtain a mixed system; carrying out heat preservation treatment on the mixed system at the temperature of 100 to 200 DEG C to obtain CTAB (Cetyltrimethyl Ammonium Bromide) modified Bi2SiO5 powder; the CTAB modified Bi2SiO5 and Mo2C are sequentially deposited on the surface of a carbon-carbon composite material in a hydrothermal electrophoretic deposition mode, then the CTAB modified bismuth silicate / molybdenum carbide / carbon-carbon composite material photoelectrocatalysis coating material is obtained through drying, the process is simple, the energy consumption is low, the cost is low, wide spectrum absorption and excellent electron migration are achieved, and the efficiency of photoelectrocatalysis water splitting oxygen production is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of photoelectrocatalytic coating materials, and specifically relates to a CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material and its preparation method. Background Technology

[0002] With a surge in global population and industrial output, energy demand has skyrocketed. Even with accelerated advocacy and adoption of renewable energy sources, including wind, hydropower, and biomass, traditional fossil fuels, including oil, natural gas, and coal, remain the primary drivers of global energy consumption. However, the overconsumption of fossil fuels significantly exacerbates carbon emissions and severe environmental problems. In contrast, solar energy is an inexhaustible and renewable natural resource.

[0003] Bismuth-based compounds include Bi₂O₃ and Bi₄Ti₃O₃. 12 Bi(OX) (X = Cl, Br, I), Bi₂WO₆, BiVO₄, BiFeO₃, and (BiO)₂CO₃ possess narrow band gaps, unique layered structures, and high visible-light photocatalytic activity. Among them, bismuth silicate (BSO) not only exhibits excellent photorefractive, photochromic, optical, and dielectric properties, but also superior photogenerated carrier mobility and strong antioxidant capacity for photogenerated holes. Although BSO is a promising visible-light photocatalyst, its application in photocatalysis is limited due to the rapid recombination of photogenerated carriers and its limited ability to absorb visible light. Since heterostructures can significantly promote the migration and separation of photogenerated carriers and the absorption of visible light, they are beneficial for improving its visible-light photocatalytic activity.

[0004] To date, numerous heterostructures containing BSO have been reported, including WO3 / Bi. 12 SiO 20 Fe3O4@SiO2 / Bi2SiO5, MoO3-Bi2SiO5 / SiO2, CQDs / Bi2SiO5, and Bi2S3 / Bi2SiO5. Although the construction of heterojunctions facilitates electron transfer and separation, making BSO a promising photoelectrochemical catalyst, Bi2S3 / Bi2SiO5, Fe3O4@SiO2 / Bi2SiO5, and WO3 / Bi 12 SiO 20 The construction of these structures sacrifices their redox capabilities, and the construction of MoO3-Bi2SiO5 / SiO2 and CQDs / Bi2SiO5 results in low specific surface areas. These heterostructures severely limit the photoelectrocatalytic efficiency of the composite materials. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material and its preparation method, in order to solve the problem of low photoelectrocatalytic efficiency of Bi2SiO5-based heterojunctions. The process is simple, energy-efficient, and low-cost, and it has broad-spectrum absorption and excellent electron mobility, which significantly improves the efficiency of photoelectrocatalytic water splitting for oxygen production.

[0006] This invention is achieved through the following technical solution: A method for preparing a CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material includes the following steps: Step 1: Adjust the pH of the mixture of bismuth nitrate pentahydrate, sodium silicate nonahydrate, and hexadecyltrimethylammonium bromide to 7-14. The mass ratio of bismuth nitrate pentahydrate to sodium silicate nonahydrate is (3-10):(1-10), and the mass ratio of hexadecyltrimethylammonium bromide to bismuth silicate is 1:(10-15), to obtain the mixed system. Step 2: The mixture is kept at 100-200 °C to obtain CTAB-modified Bi2SiO5 powder; Step 3: Using hydrothermal electrophoretic deposition, CTAB-modified Bi2SiO5 and Mo2C are sequentially deposited on the surface of the carbon-carbon composite material at a mass ratio of (0.1-0.5):(0.1-0.5), and then dried to obtain the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material.

[0007] Preferably, in step 1, the glycerol solution of bismuth nitrate pentahydrate is first added to the aqueous solution of sodium silicate nonahydrate, and then hexadecyltrimethylammonium bromide is added and mixed evenly to obtain a mixture.

[0008] Furthermore, the mass ratio of bismuth pentahydrate to glycerol in the bismuth pentahydrate glycerol solution is (3~10):(1~15), and the mass ratio of sodium nonahydrate to deionized water in the sodium nonahydrate aqueous solution is (1~10):(1~15).

[0009] Preferably, in step 1, the pH of the mixture is adjusted using a 0.1-5 M NaOH solution.

[0010] Preferably, in step 2, the mixed system is kept at 100-200 °C for 6-30 h to obtain CTAB-modified Bi2SiO5 powder.

[0011] Preferably, in step 3: the CTAB-modified Bi2SiO5 powder, isopropanol and p-benzoquinone aqueous solution are evenly dispersed according to the ratio of (0.1-0.5) g: (10-100) mL: (10-100) mL, and then iodine is added and dispersed evenly to obtain the CTAB-modified Bi2SiO5 deposition solution. Mo2C powder, isopropanol and p-benzoquinone aqueous solution were evenly dispersed in a ratio of (0.1-0.5) g: (10-100) mL: (10-100) mL, and then iodine was added and dispersed evenly to obtain Mo2C precipitate. Then, CTAB-modified Bi2SiO5 and Mo2C were deposited sequentially on the surface of the carbon-carbon composite material using CTAB-modified Bi2SiO5 deposition solution and Mo2C deposition solution, respectively.

[0012] Furthermore, in step 3, when depositing CTAB-modified Bi2SiO5 and Mo2C, the carbon-carbon composite material is used as the negative electrode, graphite is used as the positive electrode, and the deposition voltage is 0-10 V.

[0013] Furthermore, in step 3, CTAB-modified Bi2SiO5 and Mo2C are deposited sequentially on the surface of the carbon-carbon composite material for 1-20 min each time. After drying, the deposition of CTAB-modified Bi2SiO5 and Mo2C is repeated, followed by drying.

[0014] Furthermore, step 3 involves repeating the deposition of CTAB-modified Bi2SiO5 and Mo2C 5-20 times.

[0015] A CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material obtained by the preparation method of the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material described in any one of the above-mentioned methods.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for preparing a CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating. The method involves introducing the surfactant CTAB to guide the morphological growth of Bi₂SiO₅, constructing a stack of monolayer two-dimensional nanosheets linked by Bi-O bonds at a temperature of 100-200 °C. The chemical bonds between the monolayers promote electron transport, significantly enhance charge separation, and functionalize dangling bonds, even inducing new band structures. This band structure effectively regulates the solar light absorption range, improves visible light utilization, and broadens the light response range. Furthermore, the coating is further composited with Mo₂C, a transition metal carbide with metalloid properties, via hydrothermal electrophoretic deposition to construct a Schottky junction, forming a photoelectrocatalytic coating. This yields a CTAB-modified Bi₂SiO₅ / Mo₂C / carbon-carbon composite photoelectrocatalytic anode, promoting electron transfer and separation. The CTAB-modified Bi₂SiO₅ and Mo₂C exhibit good compatibility after being combined. By improving the band structure and constructing a heterostructure at a suitable position, excellent redox capabilities are ensured while the metalloid properties of Mo₂C promote electron transfer and inhibit recombination. Therefore, the CTAB-modified Bi₂SiO₅ / Mo₂C / carbon-carbon material photoelectrocatalytic anode prepared in this invention possesses both excellent electron-hole separation and mobility, as well as good photoelectrocatalytic performance. Attached Figure Description

[0017] Figure 1 The image shows the X-ray diffraction pattern of the CTAB-modified Bi2SiO5 / Mo2C / medium-density carbon-carbon composite material prepared in Example 2.

[0018] Figure 2 The image shows a scan of the CTAB-modified Bi2SiO5 prepared in Example 2.

[0019] Figure 3 This is a scan image of Mo2C prepared in Example 2.

[0020] Figure 4 The image shows a scan of the CTAB-modified Bi2SiO5 / Mo2C prepared in Example 2.

[0021] Figure 5 The image shows a scan of the CTAB-modified Bi2SiO5 / Mo2C / medium-density carbon-carbon composite material prepared in Example 2.

[0022] Figure 6 The UV-Vis diffuse reflectance spectrum of the CTAB-modified Bi2SiO5 / Mo2C prepared in Example 2.

[0023] Figure 7 The oxygen evolution performance of the CTAB-modified Bi2SiO5 / Mo2C / medium-density carbon composite material prepared in Example 2 in a solution at pH 9.5 is shown in the figure. Detailed Implementation

[0024] 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.

[0025] This invention discloses a method for preparing a CTAB-modified Bi2SiO5 / Mo2C / medium-density carbon-carbon composite photoelectrocatalytic anode, comprising the following steps: Step 1: Add sodium silicate nonahydrate to deionized water and bismuth nitrate pentahydrate to glycerol. Stir continuously until the solution is clear to obtain solution A and solution B respectively. The mass ratio of bismuth nitrate pentahydrate, sodium silicate nonahydrate, glycerol and deionized water is (3~10):(1~10):(1~15):(1~15). Step 2: After adding solution B dropwise to solution A, add 0.01-1 mol of CTAB and stir thoroughly. The mass ratio of CTAB to bismuth silicate is 1:(10-15). Adjust the pH to 7-14 with 0.1-5 M NaOH solution.

[0026] Step 3: Take a certain amount of the obtained mixed solution and fill it into the lining of the reactor. Place it in an oven at 100-200 °C for 6-30 h. After the temperature in the oven drops to room temperature, take out the reactor and cool it. After washing and drying, the powder is obtained, namely CTAB modified Bi2SiO5 powder. Step 4: Mo2C powder is prepared by calcining molybdenum trioxide and melamine in a mass ratio of (1~10):(1~10) under a nitrogen atmosphere in a solid-state method at a calcination temperature of 600-1000 ℃ and a calcination time of 2-6 h. Step 5: Place 0.1-0.5 g of CTAB-modified Bi2SiO5 powder in a beaker, then add 10 mL-100 mL of isopropanol and 10-100 mL of 0.1-0.4 M p-benzoquinone aqueous solution, stir until evenly dispersed, then add 0.1-1.0 g of iodine and continue stirring until evenly dispersed to obtain CTAB-modified Bi2SiO5 deposition solution; Take 0.1-0.5 g of Mo2C powder and place it in a beaker. Then add 10 mL-100 mL of isopropanol and 10-100 mL of 0.1-0.4 M p-benzoquinone aqueous solution, stir until evenly dispersed, and then add 0.1-1.0 g of iodine and continue stirring until evenly dispersed to obtain Mo2C precipitate. Step Six: Cut and clean the medium-density carbon-carbon composite material (density 1.3-1.5 g / cm³). 2The substrate was placed at the negative electrode of a microwave hydrothermal electrophoretic deposition apparatus, with graphite as the positive electrode. The deposition voltage was set to 0-10 V, and the apparatus was then connected. At 0 V (no voltage applied), the deposition was immersion-based, resulting in less growth and weaker bonding. With voltage applied, growth was greater and bonding stronger. Deposition was performed using CTAB-modified Bi₂SiO₅ and Mo₂C deposition solutions, respectively, for 1-20 minutes each. Afterward, the apparatus was shut down, the carbon-carbon composite substrate was removed, and dried. The dried carbon-carbon composite was then placed at the negative electrode of the hydrothermal electrophoretic deposition apparatus, and deposition was repeated 5-20 times to achieve layer-by-layer deposition. The apparatus was then shut down, the carbon-carbon composite substrate was removed, and dried to obtain the desired CTAB-modified Bi₂SiO₅ / Mo₂C / carbon-carbon composite photoelectrocatalytic anode, which can be used as a composite photoelectrocatalyst for hydrogen production.

[0027] Example 1 This embodiment provides a method for preparing a CTAB-modified Bi2SiO5 / Mo2C / carbon-carbon composite photoelectrocatalytic anode, including the following steps: Step 1: Add sodium silicate nonahydrate to deionized water and bismuth nitrate pentahydrate to glycerol. Stir continuously until the solution is clear to obtain solution A and solution B respectively. The mass ratio of bismuth nitrate pentahydrate, sodium silicate nonahydrate, glycerol and deionized water is 3:1:5:5. Step 2: After adding solution B dropwise to solution A, add 0.03 mol of CTAB and stir thoroughly. The mass ratio of CTAB to bismuth silicate is 1:10. Adjust the pH to 7 with 0.1 M NaOH solution.

[0028] Step 3: A certain amount of the obtained mixed solution is filled into the lining of the reactor and placed in an oven at 100 °C for 6 hours. After the temperature in the oven drops to room temperature, the reactor is taken out and cooled. After washing and drying, the powder is obtained, namely CTAB modified Bi2SiO5 powder. Step 4: Mo2C powder was prepared by calcining molybdenum trioxide and melamine in a mass ratio of 1:1 under a nitrogen atmosphere in a solid-state method at a calcination temperature of 600 °C and a calcination time of 2 h. Step 5: Take 0.1 g of CTAB-modified Bi2SiO5 powder and place it in a beaker. Then add 10 mL of isopropanol and 10 mL of 0.1 M p-benzoquinone aqueous solution, stir until evenly dispersed, and then add 0.1 g of elemental iodine and continue stirring until evenly dispersed to obtain CTAB-modified Bi2SiO5 deposition solution. Take 0.1 g of Mo2C powder and place it in a beaker. Then add 10 mL of isopropanol and 10 mL of 0.1 M p-benzoquinone aqueous solution, stir until evenly dispersed, and then add 0.1 g of elemental iodine and continue stirring until evenly dispersed to obtain Mo2C precipitate. Step Six: Place the cleaned and cut medium-density carbon-carbon composite substrate at the negative electrode of a microwave hydrothermal electrophoretic deposition apparatus, using graphite as the positive electrode. After setting the deposition voltage to 0 V, connect the apparatus and perform deposition using CTAB-modified Bi₂SiO₅ and Mo₂C deposition solutions, respectively, for 1 minute each. Then, turn off the apparatus, remove the carbon-carbon composite substrate, and dry it. Next, place the dried carbon-carbon composite substrate at the negative electrode of the hydrothermal electrophoretic deposition apparatus and repeat the deposition process 5 times. After that, turn off the apparatus, remove the carbon-carbon composite substrate, and dry it to obtain the desired CTAB-modified Bi₂SiO₅ / Mo₂C / carbon-carbon composite photoelectrocatalytic anode, which can be used as a composite photoelectrocatalyst for hydrogen production.

[0029] Example 2 This embodiment provides a method for preparing a CTAB-modified Bi2SiO5 / Mo2C / carbon-carbon composite photoelectrocatalytic anode, including the following steps: Step 1: Add sodium silicate nonahydrate to deionized water and bismuth nitrate pentahydrate to glycerol. Stir continuously until the solution is clear to obtain solution A and solution B respectively. The mass ratio of bismuth nitrate pentahydrate, sodium silicate nonahydrate, glycerol and deionized water is 3:1.5:10:10. Step 2: After adding solution B dropwise to solution A, add 0.05 mol of CTAB and stir thoroughly. The mass ratio of CTAB to bismuth silicate is 1:15. Adjust the pH to 13 with 2 M NaOH solution.

[0030] Step 3: A certain amount of the obtained mixed solution is filled into the lining of the reactor and placed in an oven at 200 °C for 12 h. After the temperature in the oven drops to room temperature, the reactor is taken out and cooled. After washing and drying, the powder is obtained, namely CTAB modified Bi2SiO5 powder. Step 4: Mo2C powder was prepared by calcining molybdenum trioxide and melamine in a mass ratio of 7:10 under a nitrogen atmosphere in a solid-state method at a calcination temperature of 800 °C and a calcination time of 2 h. Step 5: Take 0.3 g of CTAB-modified Bi2SiO5 powder and place it in a beaker. Then add 100 mL of isopropanol and 100 mL of 0.3 M p-benzoquinone aqueous solution, stir until evenly dispersed, and then add 0.3 g of elemental iodine and continue stirring until evenly dispersed to obtain CTAB-modified Bi2SiO5 deposition solution. Take 0.3 g of Mo2C powder and place it in a beaker. Then add 100 mL of isopropanol and 100 mL of 0.3 M p-benzoquinone aqueous solution, stir until evenly dispersed, and then add 0.3 g of iodine and continue stirring until evenly dispersed to obtain Mo2C precipitate. Step Six: Place the cleaned and cut medium-density carbon-carbon composite substrate at the negative electrode of a microwave hydrothermal electrophoretic deposition apparatus, using graphite as the positive electrode. Set the deposition voltage to 10 V and connect the apparatus. Deposit using CTAB-modified Bi₂SiO₅ and Mo₂C deposition solutions, respectively, for 20 min each. Afterward, turn off the apparatus, remove the carbon-carbon composite substrate, and dry it. Then, place the dried carbon-carbon composite substrate at the negative electrode of the hydrothermal electrophoretic deposition apparatus and repeat the deposition process 10 times. Afterward, turn off the apparatus, remove the carbon-carbon composite substrate, and dry it to obtain the desired CTAB-modified Bi₂SiO₅ / Mo₂C / carbon-carbon composite photoelectrocatalytic anode, which can be used as a composite photoelectrocatalyst for hydrogen production.

[0031] Example 3 This embodiment provides a method for preparing a CTAB-modified Bi2SiO5 / Mo2C / carbon-carbon composite photoelectrocatalytic anode, including the following steps: Step 1: Add sodium silicate nonahydrate to deionized water and bismuth nitrate pentahydrate to glycerol. Stir continuously until the solution is clear to obtain solution A and solution B respectively. The mass ratio of bismuth nitrate pentahydrate, sodium silicate nonahydrate, glycerol and deionized water is 10:10:15:15. Step 2: After adding solution B dropwise to solution A, add 1 mol of CTAB and stir thoroughly. The mass ratio of CTAB to bismuth silicate is 1:15. Adjust the pH to 14 with 5 M NaOH solution.

[0032] Step 3: A certain amount of the obtained mixed solution is filled into the lining of the reactor and placed in an oven at 200 °C for 30 h. After the temperature in the oven drops to room temperature, the reactor is taken out and cooled. After washing and drying, the powder is obtained, namely CTAB modified Bi2SiO5 powder. Step 4: Mo2C powder was prepared by calcining molybdenum trioxide and melamine in a mass ratio of 4:10 under a nitrogen atmosphere in a solid-state method at a calcination temperature of 1000 °C and a calcination time of 6 h. Step 5: Take 0.5 g of CTAB-modified Bi2SiO5 powder and place it in a beaker. Then add 100 mL of isopropanol and 100 mL of 0.4 M p-benzoquinone aqueous solution, stir until evenly dispersed, and then add 1.0 g of iodine and continue stirring until evenly dispersed to obtain CTAB-modified Bi2SiO5 deposition solution. Take 0.5 g of Mo2C powder and place it in a beaker. Then add 100 mL of isopropanol and 100 mL of 0.4 M p-benzoquinone aqueous solution, stir until evenly dispersed, and then add 1.0 g of iodine and continue stirring until evenly dispersed to obtain Mo2C precipitate. Step Six: Place the cleaned and cut medium-density carbon-carbon composite substrate at the negative electrode of a microwave hydrothermal electrophoretic deposition apparatus, using graphite as the positive electrode. Set the deposition voltage to 10 V and connect the apparatus. Deposit using CTAB-modified Bi₂SiO₅ and Mo₂C deposition solutions respectively, for 20 minutes each. Then, turn off the apparatus, remove the carbon-carbon composite substrate, and dry it. Next, place the dried carbon-carbon composite substrate at the negative electrode of the hydrothermal electrophoretic deposition apparatus and repeat the deposition process 20 times. After that, turn off the apparatus, remove the carbon-carbon composite substrate, and dry it to obtain the desired CTAB-modified Bi₂SiO₅ / Mo₂C / carbon-carbon composite photoelectrocatalytic anode, which can be used as a composite photoelectrocatalyst for hydrogen production.

[0033] from Figure 1 It can be seen that CTAB modification of Bi2SiO5 did not change the crystal phase of Bi2SiO5, and the original phase was still maintained after CTAB modification of Bi2SiO5 / Mo2C film was constructed by combining it with Mo2C.

[0034] from Figure 2 It can be seen that CTAB-modified Bi2SiO5 is in the form of thin flakes. Figure 3 It can be seen that Mo2C is stacked in blocks.

[0035] Figure 4 The image shows the scanning curve of CTAB-modified Bi2SiO5 / Mo2C, which demonstrates the effective combination of the two.

[0036] Figure 5 The figure shows that CTAB-modified Bi2SiO5 / Mo2C / carbon-carbon composite material was successfully grown on C / C.

[0037] Figure 6 BSO is obtained through step three without adding CTAB, from Figure 6 It can be seen that the light absorption of CTAB-modified Bi2SiO5 / Mo2C is broadened.

[0038] The prepared Bi₂SiO₅-Bi was studied using a Chi660e electrochemical workstation. 12 SiO 20 The photoelectrocatalytic performance of a Mo2C / medium-density carbon composite photoelectrocatalytic anode sample was tested. The specific testing procedure included cutting the composite photoelectrocatalyst into 1.5 × 1.5 cm pieces and placing them in a sodium borate buffer solution at pH 9.5 for photoelectrochemical oxygen evolution testing. Figure 7 As can be clearly seen, the photoelectrocatalyst prepared by this invention has good visible light oxygen production performance.

Claims

1. A method for preparing a CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material, characterized in that, Includes the following steps: Step 1: Adjust the pH of the mixture of bismuth nitrate pentahydrate, sodium silicate nonahydrate, and hexadecyltrimethylammonium bromide to 7-14. The mass ratio of bismuth nitrate pentahydrate to sodium silicate nonahydrate is (3-10):(1-10), and the mass ratio of hexadecyltrimethylammonium bromide to bismuth silicate is 1:(10-15), to obtain the mixed system. Step 2: The mixture is kept at 100-200 °C to obtain CTAB-modified Bi2SiO5 powder; Step 3: Using hydrothermal electrophoretic deposition, CTAB-modified Bi2SiO5 and Mo2C are sequentially deposited on the surface of the carbon-carbon composite material at a mass ratio of (0.1-0.5):(0.1-0.5), and then dried to obtain the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material.

2. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 1, characterized in that, Step 1: First, add the glycerol solution of bismuth nitrate pentahydrate to the aqueous solution of sodium silicate nonahydrate, then add hexadecyltrimethylammonium bromide and mix well to obtain a mixed solution.

3. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 2, characterized in that, The mass ratio of bismuth pentahydrate to glycerol in the bismuth pentahydrate glycerol solution is (3~10):(1~15), and the mass ratio of sodium nonahydrate to deionized water in the sodium nonahydrate aqueous solution is (1~10):(1~15).

4. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 1, characterized in that, Step 1: Adjust the pH of the mixture using a 0.1-5 M NaOH solution.

5. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 1, characterized in that, Step 2 involves heat-treating the mixture at 100-200 °C for 6-30 h to obtain CTAB-modified Bi2SiO5 powder.

6. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 1, characterized in that, In step 3: The CTAB-modified Bi2SiO5 powder, isopropanol and p-benzoquinone aqueous solution were evenly dispersed according to the ratio of (0.1-0.5) g: (10-100) mL: (10-100) mL, and then iodine was added and dispersed evenly to obtain the CTAB-modified Bi2SiO5 deposition solution. Mo2C powder, isopropanol and p-benzoquinone aqueous solution were evenly dispersed in a ratio of (0.1-0.5) g: (10-100) mL: (10-100) mL, and then iodine was added and dispersed evenly to obtain Mo2C precipitate. Then, CTAB-modified Bi2SiO5 and Mo2C were deposited sequentially on the surface of the carbon-carbon composite material using CTAB-modified Bi2SiO5 deposition solution and Mo2C deposition solution, respectively.

7. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 6, characterized in that, In step 3, when depositing CTAB-modified Bi2SiO5 and Mo2C, the carbon-carbon composite material is used as the negative electrode, graphite is used as the positive electrode, and the deposition voltage is 0-10 V.

8. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 7, characterized in that, Step 3: First, CTAB-modified Bi2SiO5 and Mo2C are deposited sequentially on the surface of the carbon-carbon composite material for 1-20 min each time. After drying, the deposition of CTAB-modified Bi2SiO5 and Mo2C is repeated, followed by drying.

9. The method for preparing the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to claim 8, characterized in that, Step 3 involves repeating the deposition of CTAB-modified Bi2SiO5 and Mo2C 5-20 times.

10. A CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material obtained by the preparation method of the CTAB-modified bismuth silicate / molybdenum carbide / carbon-carbon composite photoelectrocatalytic coating material according to any one of claims 1 to 9.

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