A kind of Bi2S3 / (Bi 0.5 Na 0.5 )TiO3 composite catalyst preparation method and its application

Abstract

The application belongs to the field of piezoelectric photocatalysts, and particularly relates to a preparation method and application of a sulfur-vacancy-containing Bi2S3 / (Bi 0.5 Na 0.5 )TiO3 composite catalyst. The application adopts a hydrothermal method to composite sulfur-vacancy-containing Bi2S3 and (Bi 0.5 Na 0.5 )TiO3 to prepare the sulfur-vacancy-containing Bi2S3 / (Bi 0.5 Na 0.5 )TiO3 composite catalyst, and the material has a high piezoelectric photocatalytic H2 production rate under the synergistic action of sunlight irradiation and ultrasonic vibration. The application has a short experimental cycle, low cost and simple preparation process. The prepared catalyst has abundant active sites, can improve the utilization rate of sunlight, and significantly improves the hydrogen production performance under the condition of ultrasonic-assisted photocatalysis.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of piezoelectric photocatalysis, and particularly relates to a preparation method and application of a BS(V) / BNT composite catalyst containing sulfur vacancies. BACKGROUND

[0002] In recent decades, with the rapid development of modern industry, environmental pollution has become a major problem. Recently, piezocatalysis based on piezoelectric materials is becoming a progressive strategy to solve environmental problems. When a mechanical force is applied, piezoelectric materials will generate polarized positive and negative charges on both sides of the catalyst surface, and subsequently form an internal electric field, which separates electrons and holes, thereby inhibiting the recombination of carriers. Although a lot of efforts have been made in the innovation of piezocatalysts, most piezocatalysts still have the problems of weak piezoelectric polarization and insufficient catalytic active sites, which seriously restrict the performance of piezocatalysis. Therefore, developing new strategies to improve the efficiency of piezocatalysis is crucial for achieving breakthroughs in piezocatalysis.

[0003] Piezocatalysis has great application potential in the field of new energy. It is of great significance to develop piezocatalysts with high hydrogen evolution reaction performance, but it is still challenging. The(Bi 0.5 Na 0.5 )TiO3(BNT) cube synthesized by hydrothermal synthesis has excellent piezocatalytic hydrogen evolution performance. Based on strong piezoelectric properties, BNT cubes allow effective water splitting through the action of ultrasonic vibration.

[0004] Combining BNT with narrow-bandgap semiconductors is a promising method to improve photocatalytic activity. Bi2S3 is a relatively narrow-bandgap semiconductor with a bandgap of about 1.2eV, which has been proven to be an excellent light absorption material. In addition, vacancy engineering (such as S vacancies) can provide more active sites and enhance the separation rate of carriers, thereby improving the hydrogen evolution performance of water splitting. There is no report on the preparation of a catalyst by combining Bi2S3 containing sulfur vacancies with(Bi 0.5 Na 0.5 )TiO3 and its application in piezo-photocatalysis. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a Bi2S3 / (Bi 0.5 Na 0.5 )TiO3 composite catalyst containing sulfur vacancies, and to apply it to piezo-photocatalytic H2 production.

[0006] The technical solution of the present application: The preparation method of the Bi2S3 / (Bi 0.5 Na 0.5 )TiO3 composite catalyst containing sulfur vacancies provided by the present application comprises the following steps:

[0007] (1)(Bi 0.5 Na 0.5 Preparation of TiO3: BiCl3 and TiO2 were added to NaOH solution and then magnetically stirred for 1.5–2.5 h to form a homogeneous suspension. The suspension was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and heated in an oven at 180–220 °C for 18–22 h. After naturally cooling to room temperature, the product was collected by vacuum filtration, washed several times with water, and dried at 60–80 °C to obtain the final product (BiCl3). 0.5 Na 0.5 TiO3.

[0008] Furthermore, the mass ratio of BiCl3 to TiO2 is (2-2.5):(1-1.4).

[0009] Furthermore, the concentration of the NaOH solution is 13–17 mol / L.

[0010] (2) Preparation of Bi2S3 containing sulfur vacancies: Bi(NO3)3·5H2O and distilled water were mixed evenly, and then CH4N2S was added and stirred for 1 h. The mixture was then transferred to a reaction vessel lined with polytetrafluoroethylene and subjected to hydrothermal reaction in an oven at a temperature of 130–150 °C for 11–13 h. After washing several times with distilled water and ethanol by centrifugation, the mixture was dried in a vacuum oven at 60–80 °C and ground to obtain black Bi2S3 containing sulfur vacancies.

[0011] Furthermore, the molar ratio of Bi(NO3)3·5H2O to CH4N2S is 1:12.

[0012] (3) Preparation of composite catalyst: Bi2S3 containing sulfur vacancies and (Bi 0.5 Na 0.5 TiO3 was dispersed in 30 ml of distilled water and reacted with stirring at room temperature for 22–24 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a gray powder containing sulfur vacancies, Bi2S3 / (Bi 0.5 Na 0.5 TiO3 composite catalyst.

[0013] Furthermore, the mass of the Bi₂S₃ containing sulfur vacancies is (Bi 0.5 Na 0.5 The content of TiO3 is 3%-12% by mass, preferably 5%;

[0014] The above-mentioned sulfur-containing Bi2S3 / (Bi 0.5 Na 0.5 The application of TiO3 composite catalysts in piezoelectric photogeneration of H2 includes: the use of Bi2S3 / (Bi2O3) catalysts containing sulfur vacancies.0.5 Na 0.5 TiO3 composite catalyst was added to distilled water, fully dispersed, and then lactic acid was added. N2 was then introduced, and finally the reaction was carried out in a closed system under ultrasonic and simulated sunlight irradiation to catalyze the production of H2.

[0015] Furthermore, the simulated sunlight is generated using a xenon lamp with a power of 50–60W.

[0016] Furthermore, the ultrasonic power is 160–180W.

[0017] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0018] (1) The catalyst provided by this invention is a Bi2S3 / (Bi2S3) containing sulfur vacancies. 0.5 Na 0.5 The TiO3 composite catalyst has simple synthesis conditions, is easy to operate, and has the characteristics of being fast, efficient, and stable.

[0019] (2) Bi2S3 containing sulfur vacancies and (Bi 0.5 Na 0.5 The composite of TiO3 can significantly improve the hydrogen production capacity under piezoelectric-photoelectric interaction, while the introduction of Bi2S3 containing sulfur vacancies does not change (Bi 0.5 Na 0.5 The crystal structure of TiO3 exhibits excellent crystallinity and purity. The mass of Bi₂S₃ containing sulfur vacancies in the composite catalyst is (Bi 0.5 Na 0.5 When TiO3 contains 5% by mass, under the synergistic effect of ultrasound and simulated sunlight, the H2 production rate can reach 1019.39 μmol / (g·h), which is higher than that of BiO3. 0.5 Na 0.5 It is 9.5 times that of TiO3, 65 times that of Bi2S3, and 15.3 times that of Bi2S3 containing sulfur vacancies. Attached image description:

[0020] Figure 1 It is the sulfur-vacancy-containing Bi2S3 / (Bi) synthesized in Example 1 0.5 Na 0.5 Scanning electron microscope image of TiO3 composite catalyst;

[0021] Figure 2 The XRD patterns of the catalysts synthesized in Comparative Example 4 (BS(V)) and Comparative Example 6 (BS) are shown.

[0022] Figure 3 These are XRD patterns of the catalysts synthesized in Examples 1, 4-6, Comparative Examples 1, 4, and 6.

[0023] Figure 4 The graph shows the performance of the catalysts synthesized in Examples 1, 4-6, Comparative Examples 1, and 5-6 in producing H2 under 55W xenon lamp irradiation and 180W ultrasonic vibration.

[0024] Figure 5 The graph shows the performance of the catalysts synthesized in Examples 1, 4-6, Comparative Examples 1, and 5-6 in producing H2 under ultrasonic vibration at 180W.

[0025] Figure 6 The graph shows the performance of the catalysts synthesized in Examples 1, 4-6, Comparative Examples 1, and 5-6 in producing H2 under 55W xenon lamp irradiation. Detailed Implementation

[0026] This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0027] The H2 production efficiency is calculated using the following formula:

[0028]

[0029] R: H2 production rate, unit: μmol / (g·h)

[0030] V: Volume of hydrogen gas, unit: μL

[0031] m: Catalyst mass, unit: g

[0032] t: Reaction time, unit: h

[0033] Example 1

[0034] (1)(Bi 0.5 Preparation of Na0.5)TiO3(BNT): 2.361 g BiCl3 and 1.2 g TiO2 were added to 50 mL of NaOH solution (15 mol / L), and then magnetically stirred for 2 h to form a homogeneous suspension. The suspension was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and heated in an oven at 200 °C for 20 h. After naturally cooling to room temperature, the product was collected by vacuum filtration, washed several times with water, and dried at 60 °C to finally obtain the product (Bi0.5)TiO3(BNT). 0.5 Na0.5)TiO3.

[0035] (2) Preparation of Bi2S3 (BS(V)) containing sulfur vacancies: 0.6064 g Bi(NO3)3·5H2O was dispersed in 60 mL of distilled water and stirred for 0.5 h. Then, 1.1418 g CH4N2S was added and stirred for another 1 h. The mixture was then transferred to a reaction vessel lined with polytetrafluoroethylene and subjected to a hydrothermal reaction in an oven at 140 °C for 12 h. After washing several times with distilled water and ethanol by centrifugation, the mixture was dried overnight in a vacuum oven at 60 °C. After grinding, black Bi2S3 containing sulfur vacancies was obtained.

[0036] (3) Preparation of composite catalyst: Bi2S3 containing sulfur vacancies and (Bi 0.5 Na0.5)TiO3 was dispersed in 30 ml of distilled water and allowed to react fully. After the reaction was complete, the mixture was filtered, washed, and dried at room temperature to obtain a gray powder containing sulfur vacancies, Bi2S3 / (Bi 0.5 Na0.5)TiO3 composite catalyst. The mass of Bi2S3 containing sulfur vacancies added is (Bi 0.5 5% of the mass of Na0.5)TiO3 is denoted as 5%BS-12 / BNT.

[0037] Application of the catalyst in catalytic H2 production: 2 mg of composite catalyst was weighed and added to 18 mL of distilled water, then sonicated for 30 min. 2 mL of lactic acid was then added, followed by N2 purging for 30 min. Finally, the mixture was sealed for 1 h under ultrasonic (180 W) and xenon lamp (55 W) irradiation. After the experiment, 0.5 mL of gas was extracted from the tube, and the peak area was detected using a gas chromatograph. The H2 production rate was calculated to be 1019.39 μmol / (g·h).

[0038] Under the same conditions, adjusting the mass of Bi₂S₃ containing sulfur vacancies is (Bi 0.5 Adding 4.5% (Na0.5)TiO3 by mass resulted in a hydrogen production rate of 478.35 μmol / (g·h); adjusting the amount of Bi2S3 containing sulfur vacancies added resulted in (Bi... 0.5 The hydrogen production rate of 5.5% (Na0.5)TiO3 by mass is 500.21 μmol / (g·h).

[0039] Example 2

[0040] Compared to Example 1, the difference lies in the application method conditions: the mixture is sealed under ultrasound (180W) for 1 hour, otherwise the conditions remain the same as in Example 1. Bi₂S₃ / (Bi) containing sulfur vacancies. 0.5 The H2 production rate of the Na0.5)TiO3 composite catalyst was 527.54 μmol / (g·h).

[0041] Example 3

[0042] Compared to Example 1, the difference lies in the application method conditions: the application is carried out under xenon lamp (55W) irradiation for 1 hour in a sealed environment; all other conditions remain the same as in Example 1. Bi₂S₃ / (Bi) containing sulfur vacancies. 0.5 The H2 production rate of the Na0.5)TiO3 composite catalyst was 118.71 μmol / (g·h).

[0043] Example 4

[0044] Compared with Example 1, the difference is that the mass of Bi2S3 containing sulfur vacancies added during the preparation process is (Bi 0.5 The Na0.5)TiO3 was 3% by mass, and the other preparation methods were the same as in Example 1.

[0045] The application method is the same as in Example 1, to obtain Bi2S3 / (Bi) containing sulfur vacancies. 0.5 The Na0.5)TiO3 composite catalyst, designated as 3%BS-12 / BNT, has an H2 production rate of 422.37 μmol / (g·h).

[0046] Example 5

[0047] Compared with Example 1, the difference is that the mass of Bi2S3 containing sulfur vacancies added during the preparation process is (Bi 0.5 The Na0.5)TiO3 was 8% by mass, and the other preparation methods were the same as in Example 1.

[0048] The application method is the same as in Example 1, to obtain Bi2S3 / (Bi) containing sulfur vacancies. 0.5 The Na0.5)TiO3 composite catalyst, designated as 8%BS-12 / BNT, has an H2 production rate of 490.43 μmol / (g·h).

[0049] Example 6

[0050] Compared with Example 1, the difference is that the mass of Bi2S3 containing sulfur vacancies added during the preparation process is (Bi 0.5 The Na0.5)TiO3 mass was 10%, and the other preparation methods were the same as in Example 1.

[0051] The application method is the same as in Example 1, and the sulfur-vacancy-containing Bi2S3 / (Bi) prepared in Example 7 is also described. 0.5 A Na0.5)TiO3 composite catalyst, designated as 10% BS-12 / BNT, exhibits an H2 production rate of 363.65 μmol / (g·h).

[0052] Example 7

[0053] The difference compared to Example 1 is: (Bi) 0.5When preparing Na0.5)TiO3(BNT), the concentration of NaOH solution was 13 mol / L, and other preparation methods were the same as in Example 1.

[0054] The application method is the same as in Example 1, and the sulfur-vacancy-containing Bi2S3 / (Bi) prepared in Example 7 is also described. 0.5 The H2 production rate of the Na0.5)TiO3 composite catalyst was 798.32 μmol / (g·h).

[0055] Example 8

[0056] The difference compared to Example 1 is: (Bi) 0.5 In the preparation of Na0.5)TiO3(BNT), the concentration of NaOH solution was 17 mol / L, and other preparation methods were the same as in Example 1.

[0057] The application method is the same as in Example 1, and the sulfur-vacancy-containing Bi2S3 / (Bi) prepared in Example 7 is also described. 0.5 The H2 production rate of the Na0.5)TiO3 composite catalyst was 675.24 μmol / (g·h).

[0058] Comparative Example 1

[0059] (Bi 0.5 Na 0.5 Preparation of TiO3(BNT): 2.361 g BiCl3 and 1.2 g TiO2 were added to 50 mL of NaOH solution (15 mol / L), and then magnetically stirred for 2 h to form a homogeneous suspension. The suspension was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and heated in an oven at 200 °C for 20 h. After naturally cooling to room temperature, the product was collected by vacuum filtration, washed several times with water, and dried at 60 °C to finally obtain the product (BiCl3(BNT)). 0.5 Na 0.5 TiO3, denoted as BNT.

[0060] Application of catalyst in catalytic H2 production: Weigh 2 mg (Bi 0.5 Na0.5TiO3 catalyst was added to 18 mL of distilled water and sonicated for 30 min. Then, 2 mL of lactic acid was added, followed by N2 purging for 30 min. Finally, the mixture was sealed for 1 h under ultrasonic (180 W) and xenon lamp (55 W) irradiation. After the experiment, 0.5 mL of gas was extracted from the tube, and the peak area was detected using a gas chromatograph. The H2 production rate was calculated, and the calculated H2 production rate was 107.44 μmol / (g·h).

[0061] Comparative Example 2

[0062] Compared with Comparative Example 1, the difference is that the application conditions were changed to: sealed under ultrasound (180W) for 1 hour, otherwise the same as Comparative Example 1. (Bi)0.5 The H2 production rate of the Na0.5)TiO3 catalyst is 87.06 μmol / (g·h).

[0063] Comparative Example 3

[0064] Compared to Comparative Example 1, the difference lies in the application method: the conditions are changed to: 1 hour of sealed exposure under xenon lamp (55W), otherwise the same as Comparative Example 1. (Bi) 0.5 The H2 production rate of the Na0.5)TiO3 catalyst is 13.13 μmol / (g·h).

[0065] Comparative Example 4

[0066] 0.6064 g of Bi(NO3)3·5H2O was dispersed in 60 mL of distilled water and stirred for 0.5 h. Then, 1.1418 g of CH4N2S was added and stirred for another 1 h. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and subjected to a hydrothermal reaction in an oven at 140 °C for 12 h. After washing several times with distilled water and ethanol by centrifugation, the mixture was dried overnight in a vacuum oven at 60 °C. After grinding, a black Bi2S3 catalyst containing sulfur vacancies was obtained.

[0067] Application of the catalyst in catalytic H2 production: 2 mg of Bi2S3 catalyst containing sulfur vacancies was weighed and added to 18 mL of distilled water, then sonicated for 30 min. Next, 2 mL of lactic acid was added, followed by N2 purging for 30 min. Finally, the mixture was sealed for 1 h under ultrasonic (180 W) and xenon lamp (55 W) irradiation. After the experiment, 0.5 mL of gas was extracted from the tube, and the peak area was detected using a gas chromatograph. The H2 production rate was calculated to be 66.66 μmol / (g·h).

[0068] Comparative Example 5

[0069] Compared with Example 1, the difference is that the mass of Bi2S3 containing sulfur vacancies added during the preparation process is (Bi 0.5 Na 0.5 The TiO3 mass was 1%, and the other preparation methods were the same as in Example 1.

[0070] The application method is the same as in Example 1 and Example 4, which prepares Bi2S3 / (Bi) containing sulfur vacancies. 0.5 Na 0.5 The H2 production rate of the TiO3 composite catalyst was 242.94 μmol / (g·h).

[0071] Comparative Example 6

[0072] (1)(Bi 0.5 Na 0.5Preparation of TiO3(BNT): 2.361 g BiCl3 and 1.2 g TiO2 were added to 50 mL of NaOH solution (15 mol / L), and then magnetically stirred for 2 h to form a homogeneous suspension. The suspension was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and heated in an oven at 200 °C for 20 h. After naturally cooling to room temperature, the product was collected by vacuum filtration, washed several times with water, and dried at 60 °C to finally obtain the product (BiCl3(BNT)). 0.5 Na 0.5 TiO3.

[0073] (2) Preparation of Bi2S3(BS): 0.6064 g Bi(NO3)3·5H2O was dispersed in 60 mL of distilled water and stirred for 0.5 h. Then, 1.903 g CH4N2S was added and stirred for another 1 h. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and subjected to a hydrothermal reaction in an oven at 140 °C for 12 h. After washing several times with distilled water and ethanol by centrifugation, the mixture was dried overnight in a vacuum oven at 60 °C and then ground to obtain BS powder.

[0074] (3) Preparation of composite catalyst: Bi2S3 and (Bi 0.5 Na 0.5 TiO3 was dispersed in 30 ml of distilled water and allowed to react fully. After the reaction was complete, the mixture was filtered, washed, and dried at room temperature to obtain a 5% BS / BNT composite catalyst. The mass of Bi2S3 added was (Bi 0.5 Na 0.5 5% of the mass of TiO3.

[0075] Application of catalyst in catalytic H2 production: Weigh 2 mg Bi2S3 / (Bi 0.5 Na 0.5 TiO3 catalyst was added to 18 mL of distilled water and sonicated for 30 min. Then 2 mL of lactic acid was added, followed by N2 purging for 30 min. Finally, the mixture was sealed under ultrasonic (180 W) and xenon lamp (55 W) irradiation for 1 h. After the experiment, 0.5 mL of gas was extracted from the tube, and the peak area was detected using a gas chromatograph. The H2 production rate was calculated to be 515.49 μmol / (g·h).

[0076] Comparative Example 7

[0077] Compared to Comparative Example 6, the difference lies in the application conditions: the conditions were changed to: 1 hour under xenon lamp (55W) irradiation in a sealed environment, while other conditions remained the same as Comparative Example 6. The H2 production rate of the BS / BNT catalyst was 53.28 μmol / (g·h).

[0078] Comparative Example 8

[0079] Compared with Comparative Example 6, the difference lies in the application conditions: the conditions were changed to: sealed under ultrasound (180W) for 1 hour, while other conditions remained the same as Comparative Example 6. The H2 production rate of the BS / BNT catalyst was 331.78 μmol / (g·h).

[0080] Comparative Example 9

[0081] Preparation of Bi2S3(BS): 0.6064 g Bi(NO3)3·5H2O was dispersed in 60 mL of distilled water and stirred for 0.5 h. Then, 1.903 g CH4N2S was added and stirred for another 1 h. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and subjected to a hydrothermal reaction in an oven at 140 °C for 12 h. After washing several times with distilled water and ethanol by centrifugation, the mixture was dried overnight in a vacuum oven at 60 °C and then ground to obtain Bi2S3.

[0082] Application of the catalyst in catalytic H2 production: 2 mg of Bi2S3 (BS) catalyst was weighed and added to 18 mL of distilled water, and the mixture was sonicated for 30 min. Then, 2 mL of lactic acid was added, followed by N2 purging for 30 min. Finally, the mixture was sealed for 1 h under ultrasonic (180 W) and xenon lamp (55 W) irradiation. After the experiment, 0.5 mL of gas was extracted from the tube, and the peak area was detected using a gas chromatograph. The H2 production rate was calculated to be 15.65 μmol / (g·h).

Claims

1. A sulfur-vacancy-containing Bi₂S₃ / (Bi 0.5 Na 0.5 The application of TiO3 composite catalysts is characterized by: Application in piezoelectric photogeneration of H2; the sulfur-vacancy-containing Bi2S3 is coated with (Bi 0.5 Na 0.5 The TiO3 surface forms a core-shell structure; the mass of the Bi2S3 containing sulfur vacancies is (Bi 0.5 Na 0.5 5% of the mass of TiO3; The application is as follows: Bi₂S₃ / (Bi) containing sulfur vacancies... 0.5 Na 0.5 TiO3 composite catalyst was added to distilled water and fully dispersed, then lactic acid was added, followed by the introduction of N2, and finally the reaction was carried out in a closed system under ultrasonic and simulated sunlight irradiation to catalyze the production of H2; the simulated sunlight was generated by a xenon lamp with a power of 50~60W; the ultrasonic power was 160~180W.

2. The sulfur-vacancy-containing Bi₂S₃ / (Bi) according to claim 1 0.5 Na 0.5 The application of TiO3 composite catalysts is characterized by: The sulfur-containing Bi2S3 / (Bi 0.5 Na 0.5 The TiO3 composite catalyst was prepared by the following steps: (1) After mixing Bi(NO3)3·5H2O and distilled water evenly, add CH4N2S and stir for 1.5~2.5h. Then transfer the mixture to a reaction vessel lined with polytetrafluoroethylene and place it in an oven for hydrothermal reaction. After centrifugation, washing, drying and grinding, Bi2S3 containing sulfur vacancies is obtained. (2) BiCl3 and TiO2 were added to a 13-17 mol / L NaOH solution and stirred for 2 hours to form a suspension. The suspension was then transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and heated at 180-220 °C for 18-22 hours. After naturally cooling to room temperature, the suspension was filtered, washed, and dried to obtain (BiCl3) 0.5 Na 0.5 TiO3; (3) Bi2S3 containing sulfur vacancies and (Bi 0.5 Na 0.5 TiO3 was dispersed in distilled water, stirred until homogeneous, and reacted at room temperature for 22-24 hours. After the reaction was completed, the mixture was filtered, washed, and dried to obtain Bi2S3 / (Bi2O3) containing sulfur vacancies. 0.5 Na 0.5 TiO3 composite catalyst.

3. The sulfur-vacancy-containing Bi₂S₃ / (Bi) according to claim 2 0.5 Na 0.5 The application of TiO3 composite catalysts is characterized by: The molar ratio of Bi(NO3)3·5H2O and CH4N2S in step (1) is 1:

12.

4. The sulfur-vacancy-containing Bi₂S₃ / (Bi) according to claim 2 0.5 Na 0.5 The application of TiO3 composite catalyst is characterized by, The hydrothermal reaction temperature in step (1) is 130~150℃ and the reaction time is 11~13h.

5. The sulfur-vacancy-containing Bi₂S₃ / (Bi) according to claim 2 0.5 Na 0.5 The application of TiO3 composite catalyst is characterized by, The mass ratio of BiCl3 to TiO2 in step (2) is (2~2.5):(1~1.4).

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