A preparation method of a Ru-modified SnS2 / SnO2 flower-shaped composite material, a hydrogen sulfide gas sensor and a preparation method thereof

Abstract

The application relates to a preparation method of a Ru-modified SnS2 / SnO2 flower-shaped composite material, a hydrogen sulfide gas sensor and a preparation method thereof, and belongs to the technical field of semiconductor gas sensitive sensors. In order to solve the technical problems of low sensitivity, low conductivity and slow response rate of a SnS2 semiconductor gas sensor, the preparation of the gas-sensitive material is as follows: SnS2 sensitive material is synthesized by using a hydrothermal method; spherical SnO2 nanoparticles are grown on the surface of the SnS2 nanoflower-shaped structure by using a secondary hydrothermal method, so as to form a two-dimensional flower-shaped structure material with surface particle distribution; the SnS2 / SnO2 material is modified by using a ruthenium acetate immersion form, and the metal hybrid modification is formed by high-temperature decomposition. The application significantly improves the sensitivity and response recovery rate of the gas-sensitive material to H2S gas, and especially realizes the ultrafast response to H2S. The gas sensor based on the Ru-modified SnS2 / SnO2 flower-shaped composite material prepared by the application has a wide prospect in the monitoring of H2S toxic gas.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor gas-sensitive sensor technology, specifically relating to a method for preparing a Ru-modified SnS2 / SnO2 flower-like composite material, a hydrogen sulfide gas sensor and its preparation method. Background Technology

[0002] Hydrogen sulfide (H2S) is an extremely dangerous, colorless, flammable gas with high corrosiveness and toxicity. Even trace amounts of H2S can be toxic to the human central nervous system and respiratory system. Industrial manufacturing and agricultural activities generate large quantities of H2S, and coal mines and wastewater treatment plants also typically produce H2S gas; H2S is also used as a biomarker for the early diagnosis of halitosis. Furthermore, the permissible exposure limit for H2S is 10 ppm, according to data from the Occupational Safety and Health Administration (OSHA). Therefore, developing a stable and sensitive H2S gas sensor is of great significance for environmental protection and human health.

[0003] Currently, common methods for detecting H2S include electrochemical sensors, gas chromatography, and light scattering. Among these, semiconductor gas sensors, with their advantages of simple structure, low cost, and rapid detection, have attracted widespread attention from various industries and fields. Therefore, designing an H2S gas sensor with high sensitivity, fast response rate, low power consumption, and ease of fabrication has become a research hotspot. SnS2 shows particular potential in gas detection applications due to its high physical affinity and suitable bandwidth. Although SnS2 has good electron-donating properties, its poor conductivity leads to high operating temperature, unsatisfactory selectivity, and slow response / recovery characteristics. Summary of the Invention

[0004] To address the technical problems of low sensitivity, low conductivity, and slow response rate in SnS2 semiconductor gas sensors, this invention provides a method for preparing Ru-modified SnS2 / SnO2 flower-like composite materials, a hydrogen sulfide gas sensor, and the method for preparing the same.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a Ru-modified SnS2 / SnO2 flower-like composite material includes the following steps:

[0007] Step 1: Add the tin source and sulfur source to solvent I, and stir evenly with a magnetic stirrer to obtain a dispersion;

[0008] Step 2: Place the dispersion in a high-pressure reactor for the first hydrothermal reaction. After the reaction is complete, cool to room temperature, open the reactor, and collect the yellow solid product obtained from the reaction, which is the crude tin disulfide product. Wash and dry the crude tin disulfide product to obtain tin disulfide powder with a two-dimensional flower-like structure.

[0009] Step 3: Dissolve the new tin source and the tin disulfide powder obtained in Step 2 in Solvent II, add solvent and catalyst, stir evenly to obtain a suspension, place the suspension in a high-pressure reactor for a second hydrothermal reaction to obtain a precipitate, pour the precipitate into a centrifuge bottle for centrifugation, washing and drying to obtain spherical SnO2 particles dispersed and embedded in flower-shaped SnS2 SnS2 SnS2 / SnO2 powder;

[0010] Step 4: Place SnS2 / SnO2 powder into a centrifuge tube, add ruthenium acetate solution, sonicate, then immerse for 1-2 hours, and finally vacuum dry to obtain Ru-modified SnS2 / SnO2 flower-like composite material.

[0011] Furthermore, in step one, the sulfur source is thioacetamide, and the tin source includes one or a combination of two of tin tetrachloride pentahydrate and anhydrous tin tetrachloride; the mass ratio of the tin source to the sulfur source is 9:(4-8).

[0012] Furthermore, in step one, the temperature of the first hydrothermal reaction is 160–200℃, and the reaction time is 20–30 h.

[0013] Furthermore, in step three, the new tin source includes one or a combination of two of tin tetrachloride pentahydrate and anhydrous tin tetrachloride; the solvent is oxalic acid, and the catalyst is polyvinylpyrrolidone; the mass ratio of the new tin source, tin disulfide, solvent and catalyst is 1:(4-5):(8-10):(4-5).

[0014] Furthermore, in step three, the temperature of the second hydrothermal reaction is 150–200°C, and the time is 20–40 hours.

[0015] Furthermore, in steps one and three, solvent I and solvent II are each independently selected from one or more combinations of isopropanol, methanol, and ethanol.

[0016] Furthermore, in step four, the mass ratio of the SnS2 / SnO2 powder to ruthenium acetate is (75-100):1, and the concentration of ruthenium acetate in the ruthenium acetate solution is 1 wt%.

[0017] A hydrogen sulfide gas sensor includes a Ru-modified SnS2 / SnO2 flower-like composite material prepared by the method described above, a sensor substrate, a signal electrode, a heating electrode, and a Ru heating film. The composite material is coated on the front side of the sensor substrate, the signal electrode is electrically connected to the composite material, the Ru heating film is disposed on the back side of the sensor substrate, and the heating electrode is electrically connected to the Ru heating film.

[0018] A method for preparing a hydrogen sulfide gas sensor includes the following steps:

[0019] Step 1: Place the Ru-modified SnS2 / SnO2 flower-like composite material into a mortar, add terpineol, mix and grind to form a slurry, coat the slurry evenly on the front side of the sensor substrate, and electrically connect the signal electrode. Then, attach the Ru heating film to the back side of the sensor substrate and electrically connect the heating electrode to obtain the gas sensor chip.

[0020] Step 2: After vacuum drying the gas sensor chip at 50-100℃ for 4 hours, weld the signal electrode and heating electrode of the gas sensor chip onto a dedicated sensor base, and then perform an aging treatment to obtain a hydrogen sulfide gas sensor.

[0021] Furthermore, in step 2, the aging temperature is 160–220°C, and the time is 48–64 hours.

[0022] This invention produces a Ru-modified SnS2 / SnO2 flower-like composite gas sensor that exhibits high sensitivity and ultrafast response recovery rate for H2S gas. The invention employs a secondary hydrothermal method to prepare SnS2 / SnO2 with spherical SnO2 particles dispersed and embedded in flower-like SnS2. Ru-modified SnS2 / SnO2 material is prepared through immersion doping. The gas sensor prepared using this material demonstrates high sensitivity and fast response when used for H2S gas sensing. This material and sensor preparation method are simple to operate, have good repeatability, low cost, and are suitable for mass production.

[0023] This invention comprises an n-type two-dimensional flower-shaped semiconductor SnS2, an n-type spherical particle semiconductor SnO2 grown on the petals, and a method of doping with noble metals on the basis of forming an n-n junction, which significantly improves the sensitivity and response recovery rate to H2S gas and improves selectivity.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) The raw materials of this invention are readily available and have low hazard, the manufacturing method is simple, and it does not pollute the environment. An H2S gas sensor based on Ru-modified SnS2 / SnO2 flower-like composite material is prepared by a simple two-step hydrothermal method and an immersion mixing and doping method. The material and sensor preparation method are simple to operate, have good repeatability, low cost, and are suitable for mass production.

[0026] (2) The Ru-modified SnS2 / SnO2 flower-like composite material prepared by the present invention has a two-dimensional flower-like structure. Spherical SnO2 nanoparticles grow and attach to the surface of the SnS2 flower-like structure. It has the characteristics of high specific surface area, multiple pores and good dispersibility, which is conducive to the adsorption and desorption of target gas, thus obtaining good gas-sensing characteristics for H2S gas.

[0027] (3) In the preparation method of Ru-modified SnS2 / SnO2 flower-like composite material, the metal Ru modification is carried out by immersing SnS2 / SnO2 powder in ruthenium acetate solution and ultrasonically dispersing it to form a suspension. The Ru ions are uniformly dispersed, which improves the adsorption activity and is beneficial to gas adsorption.

[0028] (4) An H2S gas sensor based on Ru-modified SnS2 / SnO2 flower-like composite material was used to test H2S gas at a concentration of 100 ppm. The response rate was 3.9 s, and the sensitivity was 9.89. It can achieve good detection of low-concentration gases up to 250 ppb, and has no significant response to easily interfering gases such as carbon monoxide and ethanol. The sensor fabricated in this invention exhibits superior sensitivity and ultrafast response recovery rate for H2S gas, enabling rapid measurement of H2S gas.

[0029] This invention prepares Ru-modified SnS2 / SnO2 flower-like composite materials for use in the field of H2S gas sensors. Attached Figure Description

[0030] Figure 1 The image shows a scanning electron microscope (SEM) image of the SnS2 gas-sensitive material prepared in Example 1.

[0031] Figure 2 Scanning electron microscope (SEM) image of the SnS2 / SnO2 gas-sensitive material prepared in Example 2;

[0032] Figure 3 X-ray diffraction (XRD) patterns of SnS2 gas-sensitive materials and SnS2 / SnO2 gas-sensitive materials prepared in Examples 1-2;

[0033] Figure 4 This is a front view of the H2S gas sensor prepared in Example 3; where 1 is the sensor substrate, 2 is the signal electrode, and 3 is the sensitive material layer.

[0034] Figure 5 This is a back view of the H2S gas sensor prepared in Example 3, where 4 is the heating electrode and 5 is the Ru heating film.

[0035] Figure 6 The response and sensitivity curves of the H2S gas sensors prepared in Examples 1-3 are shown.

[0036] Figure 7 This is a front view of the H2S gas sensor prepared in Example 3. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] Example 1:

[0039] The specific fabrication process for an H2S gas sensor using pure SnS2 as the sensing material is as follows:

[0040] 1. Weigh 0.9g of tin tetrachloride pentahydrate and 0.8g of thioacetamide, dissolve them in 50ml of isopropanol, and stir with a magnetic stirrer for 0.5h to obtain a uniform dispersion.

[0041] 2. Transfer the dispersion to a 100ml PPL-lined hydrothermal reactor, seal the reactor and carry out a constant temperature reaction at 180℃ for 24 hours.

[0042] 3. After the reaction is complete, let the reaction vessel cool naturally to room temperature, open the reaction vessel, place the product on a centrifuge for centrifugation at a speed of 5000 r / min for 15 min, and obtain a yellow precipitate, which is the crude tin disulfide product.

[0043] 4. The crude tin disulfide product was washed by alternating centrifugation with anhydrous ethanol and deionized water. The product was washed three times with anhydrous ethanol and three times with deionized water. The initial centrifugation speed was 5000 r / min, and the centrifugation speed was gradually reduced by 500 r / min each time as the number of washings increased. The yellow precipitate after washing and centrifugation was placed in a vacuum drying oven, and the temperature was set at 60℃ for 24 hours. After drying, a two-dimensional flower-shaped tin disulfide solid powder was obtained.

[0044] 5. Place the tin disulfide gas-sensitive material obtained in step 4 into a mortar, add terpineol, and grind to form a mixed slurry. Evenly coat this slurry onto the front side of the sensor substrate 1 to form a sensitive material layer 3. The sensitive material layer 3 is electrically connected to the signal electrode 2. A Ru heating film 5 is attached to the back side of the sensor substrate 1, and the Ru heating film 5 is electrically connected to the heating electrode 4, thus obtaining a gas sensor chip. Both the signal electrode 2 and the heating electrode 4 are made of Au, and the sensor substrate is made of alumina. There are two signal electrodes 2, respectively located at the two edges of the sensitive material layer 3, and two heating electrodes 4, respectively located at the two edges of the Ru heating film 5.

[0045] 6. Place the gas sensor chip obtained above into a vacuum drying oven for drying for 2-4 hours at a temperature of 50-100°C. Then, solder the gas sensor chip onto a dedicated sensor base and age it on an aging bench. After aging, the desired H2S gas sensor is obtained.

[0046] The optimal operating condition for the sensor is 200℃. The H2S gas sensor prepared in Example 1 was tested for H2S gas concentrations ranging from 10-100 ppm. Specifically, the H2S gas sensor was installed in a sealed test chamber. The heating voltage was adjusted to reach the operating temperature. After the sensor resistance stabilized, H2S concentrations of 10-100 ppm were injected. At each concentration point, the sensor resistance was allowed to stabilize before the H2S gas was expelled to allow the sensor resistance to recover. The test results showed a sensitivity response value of 1.57 for a 100 ppm concentration, a response time of 35 s, and a recovery time of 73 s.

[0047] Figure 1 The image shows a scanning electron microscope (SEM) image (500 nm) of the two-dimensional flower-like tin disulfide prepared in Example 1; from Figure 1 As can be seen from the microscopic view, the obtained tin disulfide is mainly composed of thin sheet-like structures similar to two-dimensional petal shapes. The thickness of each nanosheet is similar, about 50nm to 80nm. Macroscopically, these petal-like structures exhibit a flower-like petal structure. Figure 3 The XRD diffraction pattern of the two-dimensional flower-shaped tin disulfide prepared in Example 1 is included. Figure 6 The sensor response and sensitivity curves of the gas sensor prepared in Example 1 are included.

[0048] Example 2:

[0049] The specific fabrication process of an H2S gas sensor using SnS2 / SnO2 as the sensing material is as follows:

[0050] 1. Weigh 0.9g of tin tetrachloride pentahydrate and 0.8g of thioacetamide, dissolve them in 50ml of isopropanol, and stir with a magnetic stirrer for 0.5h to obtain a uniform dispersion I.

[0051] 2. Transfer Dispersion I to a 100ml PPL-lined hydrothermal reactor, seal the reactor and carry out a constant temperature reaction at 180℃ for 24 hours.

[0052] 3. After the reaction is complete, let the reaction vessel cool naturally to room temperature, open the reaction vessel, place the product on a centrifuge for centrifugation at a speed of 5000 r / min for 15 min, and obtain a yellow precipitate, which is the crude tin disulfide product.

[0053] 4. The crude tin disulfide product was washed by alternating centrifugation with anhydrous ethanol and deionized water. The product was washed three times with anhydrous ethanol and three times with deionized water. The initial centrifugation speed was 5000 r / min, and the centrifugation speed was gradually reduced by 500 r / min each time as the number of washings increased. The yellow precipitate after centrifugation and washing was placed in a vacuum drying oven, and the temperature was set at 60℃ for 24 hours. After drying, a two-dimensional flower-shaped tin disulfide solid powder was obtained.

[0054] 5. Dissolve 0.225g of tin tetrachloride pentahydrate and 0.9g of SnS2 powder obtained in step 4 above in 50ml of isopropanol, add 1.8g of oxalic acid and 1g of polyvinylpyrrolidone, stir with a magnetic stirrer for 0.5h and sonicate for 0.5h to obtain a uniform dispersion II.

[0055] 6. Transfer Dispersion II to a 100ml PPL-lined hydrothermal reactor, seal the reactor and carry out a constant temperature reaction at 180℃ for 24 hours. After the reaction is complete, allow the reactor to cool naturally to room temperature, open the reactor, and place the product on a centrifuge for centrifugation at 5000r / min for 15min to obtain a yellowish-brown precipitate, which is the crude SnS2 / SnO2 product.

[0056] 7. The crude SnS2 / SnO2 product was washed by alternating centrifugation with anhydrous ethanol and deionized water, three times with anhydrous ethanol and three times with deionized water. The initial centrifugation speed was 5000 r / min, and the centrifugation speed was gradually reduced by 500 r / min each time as the number of washings increased. The yellowish-brown precipitate after centrifugation and washing was placed in a vacuum drying oven, set at 60℃ for 24 h. After drying, SnS2 / SnO2 solid powder was obtained.

[0057] 8. Place the SnS2 / SnO2 solid powder gas-sensitive material prepared in step 7 into a mortar, add terpineol, and grind to form a mixed slurry. Evenly coat the slurry onto the front side of the sensor substrate 1 to form a sensitive material layer 3. The sensitive material layer 3 is electrically connected to the signal electrode 2. A Ru heating film 5 is attached to the back side of the sensor substrate 1, and the Ru heating film 5 is electrically connected to the heating electrode 4, thus obtaining a gas sensor chip. Both the signal electrode 2 and the heating electrode 4 are made of Au, and the sensor substrate is made of alumina. There are two signal electrodes 2, respectively located at the two edges of the sensitive material layer 3, and two heating electrodes 4, respectively located at the two edges of the Ru heating film 5.

[0058] 9. Place the gas sensor chip obtained above into a vacuum drying oven for drying for 2-4 hours at a temperature of 50-100°C. Then, solder the gas sensor chip onto a dedicated sensor base and age it on an aging bench. After aging, the prepared H2S gas sensor is obtained.

[0059] The testing method for the sensor prepared in Example 2 was the same as that in Example 1. The sensor prepared in Example 2 was tested and the sensitivity response value of the sensor was found to be 7.05.

[0060] Figure 2 The image shown is a scanning electron microscope (SEM) image (1 μm) of the SnS2 / SnO2 prepared in Example 2; from Figure 2 As can be seen, the obtained SnS2 / SnO2 is mainly composed of the flower-like structure of SnS2 and spherical SnO2 nanoparticles attached to the flower-like structure. Figure 3 The XRD diffraction pattern of SnS2 / SnO2 prepared in Example 2 is included. Figure 6 The sensor response and sensitivity curves of the gas sensor prepared in Example 2 are included.

[0061] Example 3:

[0062] An H2S gas sensor was fabricated using Ru-modified SnS2 / SnO2 as the sensing material. The specific fabrication process is as follows:

[0063] 1. Weigh 0.9g of tin tetrachloride pentahydrate and 0.8g of thioacetamide, dissolve them in 50ml of isopropanol, and stir with a magnetic stirrer for 0.5h to obtain a uniform dispersion I.

[0064] 2. Transfer Dispersion I to a 100ml PPL-lined hydrothermal reactor, seal the reactor and carry out a constant temperature reaction at 180℃ for 24 hours.

[0065] 3. After the reaction is complete, let the reaction vessel cool naturally to room temperature, open the reaction vessel, place the product on a centrifuge for centrifugation at a speed of 5000 r / min for 15 min, and obtain a yellow precipitate, which is the crude tin disulfide product.

[0066] 4. The crude tin disulfide product was washed by alternating centrifugation with anhydrous ethanol and deionized water. The product was washed three times with anhydrous ethanol and three times with deionized water. The initial centrifugation speed was 5000 r / min, and the centrifugation speed was gradually reduced by 500 r / min each time as the number of washings increased. The yellow precipitate after centrifugation and washing was placed in a vacuum drying oven, and the temperature was set at 60℃ for 24 hours. After drying, a two-dimensional flower-shaped tin disulfide solid powder was obtained.

[0067] 5. Dissolve 0.225g of tin tetrachloride pentahydrate and 0.9g of SnS2 powder obtained in step 4 above in 50ml of isopropanol, add 1.8g of oxalic acid and 1g of polyvinylpyrrolidone, stir with a magnetic stirrer for 0.5h and sonicate for 0.5h to obtain a uniform dispersion II.

[0068] 6. Transfer Dispersion II to a 100ml PPL-lined hydrothermal reactor, seal the reactor and carry out a constant temperature reaction at 180℃ for 24 hours. After the reaction is complete, allow the reactor to cool naturally to room temperature, open the reactor, and place the product on a centrifuge for centrifugation at 5000r / min for 15min to obtain a yellowish-brown precipitate, which is the crude SnS2 / SnO2 product.

[0069] 7. The crude SnS2 / SnO2 product was washed by alternating centrifugation with anhydrous ethanol and deionized water, three times with anhydrous ethanol and three times with deionized water. The initial centrifugation speed was 5000 r / min, and the centrifugation speed was gradually reduced by 500 r / min each time as the number of washings increased. The yellowish-brown precipitate after centrifugation and washing was placed in a vacuum drying oven, set at 60℃ for 24 h. After drying, SnS2 / SnO2 solid powder was obtained.

[0070] 8. Place 20 mg of the SnS2 / SnO2 powder obtained in step 7 into a centrifuge tube, add 0.02 ml of 1 wt% ruthenium acetate solution, immerse and sonicate for 20 s to form a suspension. The sonication frequency is 30-50 kHz and the power is 120-150 W. After immersion for 1.5 h, place it in a drying oven at 50 °C and vacuum dry for 6 h. After drying, a Ru-modified two-dimensional flower-like SnS2 / SnO2 gas-sensitive material is obtained.

[0071] 9. Place the Ru-modified two-dimensional flower-shaped SnS2 / SnO2 gas-sensitive material into a mortar, add terpineol, and grind to form a mixed slurry. Evenly coat the slurry onto the front side of the sensor substrate 1 to form a sensitive material layer 3. The sensitive material layer 3 is electrically connected to the signal electrode 2. A Ru heating film 5 is attached to the back side of the sensor substrate 1, and the Ru heating film 5 is electrically connected to a heating electrode 4, thus obtaining a gas sensor chip. Both the signal electrode 2 and the heating electrode 4 are made of Au, and the sensor substrate is made of alumina. There are two signal electrodes 2, respectively located at the two edges of the sensitive material layer 3, and two heating electrodes 4, respectively located at the two edges of the Ru heating film 5.

[0072] 10. Place the sensor chip obtained in step 9 into a vacuum drying oven for drying for 2-4 hours at a temperature of 50-100°C. Then, solder the gas sensor chip onto a dedicated sensor base and age it on an aging bench. After aging, the prepared H2S gas sensor is obtained.

[0073] The testing method for the sensor prepared in Example 3 was the same as that in Example 1. The H2S gas sensor prepared in Example 3 was tested and found to have a sensitivity response value of 9.89, a response time of 3.9 s, and a recovery time of 41 s.

[0074] Figure 4 This is a front view of the H2S gas sensor prepared in Example 3. Figure 5 This is a back view of the H2S gas sensor prepared in Example 3. Figure 6 Includes the response and sensitivity curves of the H2S gas sensor prepared in Example 3. Figure 7 This is a front view of the H2S gas sensor prepared in Example 3.

[0075] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a Ru-modified SnS2 / SnO2 flower-like composite material, characterized in that, Includes the following steps: Step 1: Add the tin source and sulfur source to solvent I and stir until a dispersion is obtained; Step 2: Place the dispersion in a high-pressure reactor for the first hydrothermal reaction. After the reaction is complete, cool to room temperature, collect the yellow solid product obtained from the reaction, wash and dry it to obtain tin disulfide powder with a two-dimensional flower-like structure; the temperature of the first hydrothermal reaction is 160~200℃, and the reaction time is 20~30h. Step 3: Dissolve the new tin source and tin disulfide powder in solvent II, add solvent and catalyst, stir until homogeneous to obtain a suspension, place the suspension in a high-pressure reactor for a second hydrothermal reaction to obtain a precipitate, wash and dry to obtain SnS2 / SnO2 powder with spherical SnO2 particles dispersed and embedded in flower-shaped SnS2; the new tin source includes one or a combination of two of tin tetrachloride pentahydrate and anhydrous tin tetrachloride; the solvent is oxalic acid, and the catalyst is polyvinylpyrrolidone; the mass ratio of the new tin source, tin disulfide, solvent and catalyst is 1:(4~5):(8~10):(4~5); the temperature of the second hydrothermal reaction is 150~200℃, and the time is 20~40h; solvent I and solvent II are each independently selected from one or a combination of isopropanol, methanol and ethanol; Step 4: Add ruthenium acetate solution to SnS2 / SnO2 powder, sonicate and then immerse, and then vacuum dry to obtain Ru-modified SnS2 / SnO2 flower-like composite material.

2. The preparation method according to claim 1, characterized in that: In step one, the sulfur source is thioacetamide, and the tin source includes one or a combination of two of tin tetrachloride pentahydrate and anhydrous tin tetrachloride; the mass ratio of tin source to sulfur source is 9:(4-8).

3. The preparation method according to claim 1, characterized in that: In step four, the mass ratio of SnS2 / SnO2 powder to ruthenium acetate is (75-100):1, and the concentration of ruthenium acetate in the ruthenium acetate solution is 1 wt%.

4. A hydrogen sulfide gas sensor, characterized in that: The hydrogen sulfide gas sensor comprises a Ru-modified SnS2 / SnO2 flower-like composite material prepared by the method described in any one of claims 1-3, a sensor substrate, a signal electrode, a heating electrode, and a Ru heating film. The composite material is coated on the front side of the sensor substrate, the signal electrode is electrically connected to the composite material, the Ru heating film is disposed on the back side of the sensor substrate, and the heating electrode is electrically connected to the Ru heating film.

5. A method for preparing the hydrogen sulfide gas sensor according to claim 4, characterized in that, Includes the following steps: Step 1: Mix and grind the Ru-modified SnS2 / SnO2 flower-like composite material with terpineol to form a mixed slurry. Coat the slurry evenly on the front side of the sensor substrate and electrically connect the signal electrode. Attach the Ru heating film to the back side of the sensor substrate and electrically connect the heating electrode to obtain the gas sensor chip. Step 2: After vacuum drying the gas sensor chip, solder the gas sensor chip onto a dedicated sensor base, and then perform an aging treatment to obtain a hydrogen sulfide gas sensor.

6. The preparation method according to claim 5, characterized in that: In step 2, the aging temperature is 160~220℃ and the time is 48~64h.

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