Preparation Method and Application of a Bismuth Sulfide / Zinc Oxide Heterojunction Material

Abstract

Preparation method and application of bismuth sulfide / zinc oxide heterojunction material, which solves the problem that the gas sensor prepared from Bi2S3-based heterostructure can only detect H2S gas under dark conditions, while there are still problems of low response value and poor selectivity under visible light conditions. Method: Synthesize Bi2S3 nanowires, and mechanically mix them with ZnO nanoparticles to form a Bi2S3 / ZnO heterostructure. Regulate the quantity of zinc oxide, change the electronic structure of bismuth sulfide, improve the surface adsorption active sites, and then improve the response value and selectivity for detecting H2S under room temperature visible light, and shorten the response time. After the surface of Bi2S3 nanowires is modified with ZnO in the present invention, it has a response value of 16.0 times for 500 ppb of H2S under room temperature visible light, the response time is only 51.6 s, and it has good selectivity, low cost and simple process, and is suitable for industrial production. It is used for rapid detection of H2S under room temperature and visible light conditions.

Description

Technical Field

[0001] The present invention specifically relates to a preparation method and application of a bismuth sulfide / zinc oxide heterojunction material. Background Art

[0002] Hydrogen sulfide (H2S) is a colorless, flammable, toxic gas with a rotten egg odor, and is one of the threats causing environmental pollution and affecting human health. In recent years, H2S gas detection has been gradually applied to the fields of medicine and food detection, and non-invasive diagnosis is achieved by detecting the content of H2S in human exhaled gas. In addition, H2S gas is a marker gas for food spoilage, and the freshness of food can be evaluated by H2S gas detection. Therefore, it is very important to explore a sensor that can sensitively respond to low-concentration H2S gas in a complex environment. Among various types of gas sensors, planar resistive sensors are widely used to prepare various gas sensors due to their advantages of non-toxicity, low cost, small device volume, and integrability. Currently, commercially available gas sensors based on semiconductor metal oxides have played an important role in production and life. However, metal oxides have poor room-temperature conductivity and usually need to work under high-temperature (250°C - 700°C) conditions, and heating the sensor leads to high power consumption of the sensor, complex preparation processes, and the side effects of the heating current can cause losses to the device itself. Therefore, the development of gas-sensitive materials for use at room temperature is of great significance for breaking through the development bottleneck of existing planar resistive gas sensors.

[0003] Bismuth sulfide (Bi2S3) is a narrow-bandgap semiconductor that easily forms a nanowire structure and has unique properties such as a large specific surface area and strong surface activity. The carrier mobility is about 10 3 cm 2 V -1 s -1 , enabling room-temperature detection of gases. However, currently, gas sensors prepared based on Bi2S3 still have problems of low sensitivity and difficulty in detecting ppb-level concentrations when detecting H2S. By constructing a heterojunction, the active sites for gas adsorption can be increased, and the electronic structure of the system can be adjusted to achieve the effects of improving the response value and shortening the response / recovery time. Currently, the reported Bi2S3-based heterostructures available for H2S detection mainly include Bi2S3 / ZnS and Bi2S3 / SnS2. Both heterostructures have good H2S detection performance only in a dark environment. Under visible light irradiation conditions, the response values of both heterostructures to H2S gas are relatively low, and the difference in the response values of the Bi2S3 / ZnS heterostructure to H2S and NO2 gases under visible light irradiation conditions is small, that is, the selectivity is poor. Therefore, it is urgent to develop a new type of Bi2S3-based heterojunction material with high response value and high selectivity for H2S detection performance under visible light irradiation conditions, which is of great significance for expanding the application fields of H2S gas sensors. Summary of the Invention

[0004] The object of the present invention is to solve the problem that the gas sensor prepared from the Bi2S3-based heterostructure can only detect H2S gas under dark conditions, and there are still problems of low response value and poor selectivity under visible light conditions, and to provide a preparation method and application of a bismuth sulfide / zinc oxide heterojunction material.

[0005] A preparation method of a bismuth sulfide / zinc oxide heterojunction material is realized according to the following steps:

[0006] First, solution B is slowly added dropwise to vigorously stirred solution A, stirred for 0.5 h to 1 h, then transferred to the inner liner of a 50 mL polytetrafluoroethylene hydrothermal autoclave for reaction. The obtained solid particles are washed and dried to obtain Bi2S3. Then, Bi2S3 is dissolved in absolute ethanol and ultrasonically dispersed for 20 min to 60 min to obtain a Bi2S3 dispersion with a concentration of 0.001 mol / L to 0.01 mol / L.

[0007] Second, solution C is cooled to 20°C to 50°C in air, then solution D is added to solution C, stirred for 5 s to 30 s, and then cooled in cold water and continuously stirred to obtain a ZnO solution.

[0008] Third, take 50 μL to 5000 μL of the above ZnO solution, add it to 1 mL to 50 mL of absolute ethanol and ultrasonically disperse it, then drop it into the above Bi2S3 dispersion to obtain a mixed solution. After stirring at room temperature for 1 h to 3 h, centrifuge to take the lower layer precipitate, wash and dry it to obtain the Bi2S3 / ZnO heterojunction material, and thus complete the preparation method;

[0009] Among them, in step one, solution A: bismuth nitrate pentahydrate is added to ethylene glycol and stirred until completely dissolved to obtain solution A;

[0010] Solution B in step one: sodium sulfide nonahydrate is added to ethylene glycol, ultrasonically dissolved and dispersed evenly to obtain solution B;

[0011] Solution C in step two: zinc acetate dihydrate is dissolved in absolute ethanol and heated in a water bath at 60°C to 120°C for 1 h to 3 h to obtain solution C;

[0012] Solution D in step two: solid NaOH is dissolved in absolute ethanol and stirred to form a NaOH ethanol solution to obtain solution D.

[0013] Further, the concentration of solution A in step one is 0.01 mol / L to 0.1 mol / L; the concentration of solution B is 0.01 mol / L to 0.1 mol / L.

[0014] Further, the volume ratio of solution A to solution B in step one is 1:(1 - 3).

[0015] Further, the reaction in step one: reacts at 150°C - 220°C for 6h - 12h.

[0016] Further, the cleaning and drying in step one: are each cleaned 3 - 5 times with ultrapure water and absolute ethanol, and then dried at 60°C - 80°C for 6h - 12h.

[0017] Further, the slow dropping in step one: the dropping rate is 10 - 60 drops / min.

[0018] Further, the concentration of solution C in step two is 0.01mol / L - 0.1mol / L; the concentration of solution D is 10g / L - 50g / L.

[0019] Further, the volume ratio of solution D to solution C in step two is 1:(6 - 30).

[0020] Further, the cooling in cold water in step two: cools to 0 - 10°C in water at 0 - 5°C.

[0021] Further, the cleaning and drying in step three: are each cleaned 3 - 5 times with ultrapure water and absolute ethanol, and then dried at 60°C - 100°C for 6h - 24h.

[0022] Further, the molar ratio of Bi2S3 to ZnO in the mixed solution in step three is 1:(0.01 - 0.3).

[0023] Application of the prepared bismuth sulfide / zinc oxide heterojunction material: Prepare the Bi2S3 / ZnO heterojunction material into an electrode sheet for rapid detection of H2S at room temperature under visible light conditions.

[0024] Advantages of the present invention:

[0025] 1. In the present invention, Bi2S3 nanowires are synthesized by a hydrothermal method, and then ZnO nanoparticles are modified onto the surface of Bi2S3 nanowires by mechanical mixing with ZnO nanoparticles to form a Bi2S3 / ZnO heterojunction. By regulating the quantity of ZnO, the electronic structure of Bi2S3 is changed, and the surface adsorption active sites are increased, thereby increasing the response value of H2S detection at room temperature and shortening the response time.

[0026] 2. The Bi2S3 / ZnO heterojunction material obtained in the present invention solves the problem that the gas sensor prepared from the Bi2S3-based heterostructure can only detect H2S gas under dark conditions, while there are still problems of low response value and poor selectivity under visible light illumination conditions. After the surface of Bi2S3 nanowires is modified with ZnO in the present invention, it has a response value 16.0 times that of 500 ppb of H2S under room temperature and visible light illumination conditions, and has the advantages of high response value and high selectivity. It not only overcomes the disadvantage that ZnO cannot work at room temperature, but also has a response value 3 times higher than that of pure-phase Bi2S3, and the response time is shortened from 233.2 s to 51.6 s. The preparation method of the present invention has low cost and simple process, and is suitable for industrial production.

[0027] The Bi2S3 / ZnO heterojunction material prepared in the present invention is used for rapid detection of H2S under room temperature and visible light conditions. Brief Description of the Drawings

[0028] Figure 1 SEM image of Bi2S3 prepared in the example;

[0029] Figure 2 SEM image of the Bi2S3 / ZnO heterostructure prepared in the example;

[0030] Figure 3 XRD comparison chart of the Bi2S3 / ZnO heterostructure prepared in the example with pure-phase Bi2S3 and ZnO, where 1 represents the synthesized pure-phase ZnO, 2 represents the Bi2S3 / ZnO heterostructure, 3 represents the synthesized pure-phase Bi2S3, 4 represents JCPDS: 89-0511 (standard PDF card of ZnO), and 5 represents JCPDS: 84-0279 (standard PDF card of Bi2S3);

[0031] Figure 4 HRTEM image of the Bi2S3 / ZnO heterostructure prepared in the example;

[0032] Figure 5 For Figure 4 Local enlarged HRTEM image of area A in

[0033] Figure 6 Comparison chart of the sensing performance differences of the Bi2S3 / ZnO heterojunction material for detecting H2S under visible light illumination conditions and dark conditions in the example, where 1 represents under visible light conditions and 2 represents under dark conditions;

[0034] Figure 7 Comparison chart of the H2S sensing response value differences of the Bi2S3 / ZnO heterostructure prepared in the example under room temperature and visible light illumination conditions, where 1 represents Bi2S3 and 2 represents the Bi2S3 / ZnO heterojunction material;

[0035] Figure 8 It is a comparison chart of the response times of the Bi2S3 / ZnO heterojunction material prepared in the examples and pure-phase Bi2S3, where 1 represents Bi2S3 and 2 represents the Bi2S3 / ZnO heterojunction material;

[0036] Figure 9 It is a dynamic response curve graph for detecting H2S under visible light irradiation at room temperature of the Bi2S3 / ZnO heterojunction material prepared in the examples;

[0037] Figure 10 It is a curve graph showing the change of the response value with the H2S concentration when the Bi2S3 / ZnO heterojunction material prepared in the examples detects H2S under visible light irradiation at room temperature;

[0038] Figure 11 It is a selectivity test graph for the Bi2S3 / ZnO heterojunction material prepared in the examples to detect H2S under visible light irradiation at room temperature. Specific Embodiments

[0039] The technical solution of the present invention is not limited to the following specific embodiments listed, and also includes any combination between the specific embodiments.

[0040] Specific Embodiment 1: A preparation method of a bismuth sulfide / zinc oxide heterojunction material, which is realized according to the following steps:

[0041] I. Slowly drop solution B into vigorously stirred solution A, stir for 0.5 h to 1 h, then transfer it to the inner liner of a 50 mL polytetrafluoroethylene hydrothermal autoclave for reaction. The obtained solid particles are washed and dried to obtain Bi2S3. Then dissolve Bi2S3 in absolute ethanol and ultrasonically disperse it for 20 min to 60 min to obtain a Bi2S3 dispersion with a concentration of 0.001 mol / L to 0.01 mol / L;

[0042] II. Cool solution C in air to 20 °C to 50 °C, then add solution D to solution C, stir for 5 s to 30 s, then cool it in cold water and continue stirring to obtain a ZnO solution;

[0043] III. Take 50 μL to 5000 μL of the above ZnO solution, add it to 1 mL to 50 mL of absolute ethanol and ultrasonically disperse it, then drop it into the above Bi2S3 dispersion to obtain a mixed solution. Stir at room temperature for 1 h to 3 h, then centrifuge to take the lower-layer precipitate, wash and dry it to obtain the Bi2S3 / ZnO heterojunction material, thus completing the preparation method;

[0044] Among them, in step I, solution A: Add bismuth nitrate pentahydrate to ethylene glycol and stir until completely dissolved to obtain solution A;

[0045] Solution B described in Step 1: Add sodium sulfide nonahydrate to ethylene glycol, ultrasonically dissolve and disperse evenly to obtain Solution B;

[0046] Solution C described in Step 2: Dissolve zinc acetate dihydrate in absolute ethanol, and heat it in a water bath at 60°C - 120°C for 1h - 3h to obtain Solution C;

[0047] Solution D described in Step 2: Dissolve solid NaOH in absolute ethanol, stir to form an NaOH ethanol solution to obtain Solution D.

[0048] In Step 1 of this embodiment, the stirring speed used for the vigorous stirring is 800 r / min.

[0049] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that the concentration of Solution A in Step 1 is 0.01 mol / L - 0.1 mol / L; the concentration of Solution B is 0.01 mol / L - 0.1 mol / L. Other steps and parameters are the same as those in Specific Embodiment 1.

[0050] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 or 2 is that the volume ratio of Solution A to Solution B in Step 1 is 1:(1 - 3). Other steps and parameters are the same as those in Specific Embodiment 1 or 2.

[0051] Specific Embodiment 4: The difference between this embodiment and any one of Specific Embodiments 1 to 3 is that the reaction in Step 1 is carried out at 150°C - 220°C for 6h - 12h. Other steps and parameters are the same as those in any one of Specific Embodiments 1 to 3.

[0052] Specific Embodiment 5: The difference between this embodiment and any one of Specific Embodiments 1 to 4 is that the cleaning and drying in Step 1 are carried out by cleaning 3 - 5 times each with ultrapure water and absolute ethanol, and then drying at 60°C - 80°C for 6h - 12h. Other steps and parameters are the same as those in any one of Specific Embodiments 1 to 4.

[0053] Specific Embodiment 6: The difference between this embodiment and any one of Specific Embodiments 1 to 5 is that the slow dropping in Step 1: The dropping rate is 10 - 60 drops / min. Other steps and parameters are the same as those in any one of Specific Embodiments 1 to 5.

[0054] Specific Embodiment 7: The difference between this embodiment and any one of Specific Embodiments 1 to 6 is that the concentration of Solution C in Step 2 is 0.01 mol / L - 0.1 mol / L; the concentration of Solution D is 10 g / L - 50 g / L. Other steps and parameters are the same as those in any one of Specific Embodiments 1 to 6.

[0055] Embodiment VIII: The difference between this embodiment and any one of Embodiments I - VII is that the volume ratio of Solution D to Solution C in Step 2 is 1:(6 - 30). Other steps and parameters are the same as those in any one of Embodiments I - VII.

[0056] Embodiment IX: The difference between this embodiment and any one of Embodiments I - VIII is that in Step 2, cooling in cold water: cooling to 0 - 10°C in water at 0 - 5°C. Other steps and parameters are the same as those in any one of Embodiments I - VIII.

[0057] Embodiment X: The difference between this embodiment and any one of Embodiments I - IX is that in Step 3, cleaning and drying: cleaning 3 - 5 times each with ultrapure water and absolute ethanol, and then drying at 60°C - 100°C for 6h - 24h. Other steps and parameters are the same as those in any one of Embodiments I - IX.

[0058] Embodiment XI: The difference between this embodiment and any one of Embodiments I - X is that in Step 3, the molar ratio of Bi2S3 to ZnO in the mixed solution is 1:(0.01 - 0.3). Other steps and parameters are the same as those in any one of Embodiments I - X.

[0059] Embodiment XII: Application of the Bi2S3 / ZnO heterojunction material. The Bi2S3 / ZnO heterojunction material is prepared into an electrode sheet for rapid detection of H2S under room temperature and visible light conditions.

[0060] In this embodiment, the process of preparing the Bi2S3 / ZnO heterojunction material into an electrode sheet: Dissolve the Bi2S3 / ZnO heterojunction material in absolute ethanol to prepare a solution with a concentration of 10mg / mL. After ultrasonic treatment for 10 minutes, a dispersion of the Bi2S3 / ZnO heterojunction material is obtained. The dispersion of the Bi2S3 / ZnO heterojunction material is dropped onto the surface of the electrode sheet by the dropping method and dried at 70°C for 1 hour. After the absolute ethanol solvent evaporates, the Bi2S3 / ZnO heterojunction material will form a uniform thin film on the electrode surface, and this electrode sheet can be directly used for gas - sensing performance testing.

[0061] In this embodiment, the concentration range for rapid detection of H2S is 0.02ppm - 8ppm.

[0062] The beneficial effects of the present invention are verified through the following examples:

[0063] Example:

[0064] A preparation method of a bismuth sulfide / zinc oxide heterojunction material, which is realized according to the following steps:

[0065] 1. Slowly add solution B dropwise to vigorously stirred solution A. After stirring for 1 h, transfer it to the inner liner of a 50 mL polytetrafluoroethylene hydrothermal reactor for reaction. The obtained solid particles are washed and dried to obtain Bi2S3. Then, dissolve Bi2S3 in absolute ethanol and ultrasonically disperse it for 30 min to obtain a Bi2S3 dispersion with a concentration of 0.002 mol / L.

[0066] 2. Cool solution C to 40 °C in air, then add solution D to solution C. After stirring for 10 s, cool it in cold water and continue stirring to obtain a ZnO solution.

[0067] 3. Take 800 μL of the above ZnO solution, add it to 10 mL of absolute ethanol and ultrasonically disperse it, then drop it into the above Bi2S3 dispersion to obtain a mixed solution. After stirring at room temperature for 2 h, centrifuge and take the lower precipitate. After washing and drying, a Bi2S3 / ZnO heterojunction material is obtained, thus completing the preparation method.

[0068] Among them, in step 1, solution A: Add 1 mmol (0.485 g) of bismuth nitrate pentahydrate to 15 mL of ethylene glycol, stir until completely dissolved to obtain solution A.

[0069] In step 1, solution B: Add 2 mmol (0.480 g) of sodium sulfide nonahydrate to 15 mL of ethylene glycol, ultrasonically dissolve and disperse evenly to obtain solution B.

[0070] In step 2, solution C: Dissolve 1.75 mmol (0.384 g) of zinc acetate dihydrate in 35 mL of absolute ethanol, and heat it in a water bath at 80 °C for 2 h to obtain solution C.

[0071] In step 2, solution D: Dissolve 0.3 g of solid NaOH in 10 mL of absolute ethanol, stir to form a NaOH ethanol solution to obtain solution D.

[0072] In step 1 of this example, the volume ratio of solution A to solution B is 1:1.

[0073] In step 1 of this example, the reaction: React at 180 °C for 12 h.

[0074] In step 1 of this example, the washing and drying: Wash 3 times each with ultrapure water and absolute ethanol, and then dry at 60 °C for 12 h.

[0075] In step 1 of this example, the slow dropwise addition: The dropping rate is 30 drops / min.

[0076] In step 2 of this example, the volume ratio of solution D to solution C is 1:10.

[0077] Cooling in cold water in Step 2 of this embodiment: Cool to 5°C in water at 0°C.

[0078] Cleaning and drying in Step 3 of this embodiment: Clean 3 times each with ultrapure water and absolute ethanol, and then dry at 60°C for 12 h.

[0079] The Bi2S3 prepared in Step 1 of this embodiment has a scanning electron micrograph as Figure 1 shown. Bi2S3 is in the shape of nanorods with a length of about 5 μm. After further loading ZnO nanoparticles by mechanical mixing, the formed Bi2S3 / ZnO heterostructure has ZnO nanoparticles dotted on the surface of Bi2S3 nanorods, and its scanning electron microscope is as Figure 2 shown. The XRD pattern of this material is as Figure 3 shown. The XRD data of the Bi2S3 / ZnO heterojunction material is consistent with the XRD data of pure-phase Bi2S3, which can further illustrate that the composite ZnO nanoparticles do not affect the crystal structure of Bi2S3. No diffraction peaks related to ZnO are observed in the composite, mainly due to the small amount of ZnO in the composite. To further confirm that the nanoparticles on the surface of Bi2S3 nanowires are ZnO nanoparticles, high-resolution transmission electron microscopy was tested, as Figure 4 shown. Lattice fringes with a clear spacing of 0.379 nm can be observed, which belong to the (110) plane of Bi2S3. Region A was locally magnified, as Figure 5 shown. Lattice fringes with a spacing of 0.251 nm can be observed, which belong to the (101) plane of ZnO. The above data prove that the Bi2S3 / ZnO heterojunction material was successfully synthesized, and ZnO nanoparticles are deposited on the surface of Bi2S3 nanowires without affecting the crystal structure of Bi2S3.

[0080] Dissolve the Bi2S3 / ZnO heterojunction material in absolute ethanol to prepare a 10 mg / mL solution. After ultrasonic treatment for 10 min, a dispersion of the Bi2S3 / ZnO heterojunction material is obtained. Drop the dispersion of the Bi2S3 / ZnO heterojunction material onto the surface of the electrode sheet by the dropping method and dry it at 70°C for 1 h. After the absolute ethanol solvent evaporates, the Bi2S3 / ZnO heterojunction material will form a uniform thin film on the electrode surface, and this electrode sheet can be directly used for gas-sensing performance testing. The gas-sensing performance is tested by an electrochemical workstation. The sensitivity S of the sensor is defined as: S = R a / R g , where R a is the resistance of the sensor in air, and R gis the resistance value of the sensor in H2S. First, the difference in the sensing performance of the Bi2S3 / ZnO heterojunction material for detecting H2S under visible light illumination and in the dark was compared. It was found that the difference in the detection of H2S by this material under visible light illumination and in the dark was small, as Figure 6 shown. Further, the performance differences between the Bi2S3 / ZnO heterojunction material and pure-phase Bi2S3 and pure-phase ZnO under visible light illumination were compared. Regarding the response value of the sensor, it is defined as the ratio of the resistance of the sensor before and after contacting the target gas (R g is the resistance in the gas to be measured, R a is the resistance of the sensor in air. If R g >R a , the response value is R g / R a ; if R g <R a , the response value is R a / R g ). The test results are as Figure 7 shown. When detecting 500 ppb H2S, the response value of the Bi2S3 / ZnO heterojunction material is 16 times, while the response value of pure-phase Bi2S3 is only 4 times. Pure-phase ZnO cannot detect H2S at room temperature due to its too large resistance value. Regarding the response time of the sensor, it is defined as the time required from when the sensor contacts a certain concentration of the measured gas until its resistance reaches 90% of the stable resistance value at this concentration. The test results are as Figure 8 shown. The response time of pure-phase Bi2S3 is 233.2 s, while the response time of the Bi2S3 / ZnO heterojunction material is shortened to 51.6 s. This shows that constructing the Bi2S3 / ZnO heterostructure can not only effectively enhance the response value but also significantly shorten the response time of the material. Figure 9 is the relationship curve of the response value varying with the H2S concentration of the sensor prepared with the Bi2S3 / ZnO heterojunction gas-sensitive material prepared in this embodiment under visible light illumination. The H2S concentration is between 0.02 and 8 ppm. As the H2S concentration increases, the response value of the sensor first shows a linear increasing trend and then gradually reaches saturation, as Figure 10 shown. The Bi2S3 / ZnO sensor prepared in this embodiment also has good selectivity under visible light illumination, as Figure 11 shown.

[0081] Therefore, the Bi2S3 / ZnO heterojunction material obtained in this embodiment solves the problem that the gas sensor prepared by the existing Bi2S3-based heterostructure can only detect H2S gas under dark conditions, while there are still problems of low response value and poor selectivity under visible light conditions, and realizes high response value, high selectivity and rapid H2S detection under visible light irradiation at room temperature. The preparation method in this embodiment has low cost and simple preparation process, and is suitable for industrial production.

Claims

1. A preparation method of a bismuth sulfide / zinc oxide heterojunction material, characterized in that It is realized according to the following steps: First, slowly drop solution B into vigorously stirred solution A. After stirring for 0.5 h to 1 h, transfer it to the inner liner of a 50 mL polytetrafluoroethylene hydrothermal autoclave for reaction. The obtained solid particles are washed and dried to obtain Bi2S3. Then, dissolve Bi2S3 in absolute ethanol and ultrasonically disperse it for 20 min to 60 min to obtain a Bi2S3 dispersion with a concentration of 0.001 mol / L to 0.01 mol / L. Second, cool solution C in air to 20 °C to 50 °C, then add solution D to solution C. After stirring for 5 s to 30 s, cool it in cold water and continue stirring to obtain a ZnO solution. Third, take 50 μL to 5000 μL of the above ZnO solution, add it to 1 mL to 50 mL of absolute ethanol and ultrasonically disperse it, then drop it into the above Bi2S3 dispersion to obtain a mixed solution. After stirring at room temperature for 1 h to 3 h, centrifuge to take the lower-layer precipitate, wash and dry it to obtain the Bi2S3 / ZnO heterojunction material, thus completing the preparation method. Among them, in step one, solution A: Add bismuth nitrate pentahydrate to ethylene glycol and stir until completely dissolved to obtain solution A. In step one, solution B: Add sodium sulfide nonahydrate to ethylene glycol, ultrasonically dissolve and disperse it evenly to obtain solution B. In step two, solution C: Dissolve zinc acetate dihydrate in absolute ethanol and heat it in a water bath at 60 °C to 120 °C for 1 h to 3 h to obtain solution C. In step two, solution D: Dissolve solid NaOH in absolute ethanol and stir to form a NaOH ethanol solution to obtain solution D.

2. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, wherein In step one, the concentration of solution A is 0.01 mol / L to 0.1 mol / L; the concentration of solution B is 0.01 mol / L to 0.1 mol / L.

3. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, wherein In step one, the volume ratio of solution A to solution B is 1: (1 to 3).

4. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, characterized in that In step one, the reaction: React at 150 °C to 220 °C for 6 h to 12 h.

5. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, characterized in that In step one, the washing and drying: Wash 3 to 5 times with ultrapure water and absolute ethanol respectively, and then dry at 60 °C to 80 °C for 6 h to 12 h.

6. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, characterized in that In step two, the concentration of solution C is 0.01 mol / L to 0.1 mol / L; the concentration of solution D is 10 g / L to 50 g / L.

7. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, wherein In step two, the volume ratio of solution D to solution C is 1: (6 to 30).

8. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, wherein In step three, the washing and drying: Wash 3 to 5 times with ultrapure water and absolute ethanol respectively, and then dry at 60 °C to 100 °C for 6 h to 24 h.

9. The preparation method of a bismuth sulfide / zinc oxide heterojunction material according to claim 1, characterized in that In step three, the molar ratio of Bi2S3 to ZnO in the mixed solution is 1: (0.01 to 0.3).

10. The application of the bismuth sulfide / zinc oxide heterojunction material according to claim 1, characterized in that Prepare the Bi2S3 / ZnO heterojunction material into an electrode sheet for rapid detection of H2S at room temperature under visible light conditions.

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