SnS2 / Nb2CT x Preparation method of heterojunction composite gas-sensitive material
Patent Information
- Application Number
- CN202611024454.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-10
- Publication Date
- 2026-09-25
AI Technical Summary
但纯 Nb2CTx传感器存在灵敏度低、检测浓度范围窄、抗干扰能力弱的问题，严重限制其实际应用
本发明制备的SnS2/Nb2CTx异质结复合气敏材料，具备更大比表面积、更丰富活性位点及更优异导电性，能够为 NH3分子提供高效的吸附与反应场所，在氨气气敏传感器领域具有重要的研究价值与应用意义。
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Figure CN122809523A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of gas-sensitive sensing material preparation technology, specifically relating to SnS2 / Nb2CT. x The preparation method of heterojunction composite gas-sensitive material also involves the SnS2 / Nb2CT. x Applications of heterojunction composite gas-sensitive materials. Background Technology
[0002] NH3, a typical toxic volatile gas, is widely present in agricultural production, industrial exhaust emissions, and food spoilage processes. It is also a potential biomarker in the exhaled breath of patients with chronic kidney disease. Accurate and rapid detection and differentiation of NH3 has significant value for environmental monitoring and health protection.
[0003] Traditional ammonia gas sensors generally suffer from poor selectivity, complex operation procedures, and high power consumption. Interface engineering techniques for two-dimensional transition metal sulfides (TMDs) offer a new research direction for optimizing the performance of gas sensors. Nb2CT x As an important member of the MXene family, it possesses characteristics such as large specific surface area, high electrical conductivity, and a surface rich in active functional groups such as -F and -OH, giving it potential application value in the field of gas sensing. However, pure Nb2CT... x The sensor suffers from low sensitivity, narrow detection concentration range, and weak anti-interference ability, which severely limits its practical application.
[0004] SnS2 is a typical two-dimensional transition metal dichalcogenide (TMD), possessing characteristics such as high carrier mobility, large adsorption coefficient, and tunable band gap. Modifying Nb2CT with SnS2... x On the surface, a composite material with a heterojunction structure can be constructed. This composite material can both promote the adsorption of NH3 molecules and accelerate the interfacial electron transfer, thereby significantly enhancing the ammonia detection performance. Summary of the Invention
[0005] The first objective of this invention is to provide SnS2 / Nb2CT. x A method for preparing heterojunction composite gas-sensitive materials, which can achieve highly selective recognition and highly sensitive response to NH3.
[0006] A second objective of this invention is to provide SnS2 / Nb2CT. x Heterojunction composite gas-sensitive materials.
[0007] A third objective of this invention is to provide SnS2 / Nb2CT. x Application of heterojunction composite gas-sensitive materials in ammonia detection gas sensors.
[0008] The first technical solution adopted in this invention is SnS2 / Nb2CT. x The preparation method of heterojunction composite gas-sensitive materials is carried out according to the following steps: Step 1: Using Nb2AlC powder as raw material, Nb2CT is obtained by HF etching. x Powder; then Nb2CT x The powder was dispersed in distilled water and stirred to obtain Nb2CT. x Solution; Step 2, to Nb2CT x Add tin tetrachloride and thiourea to the solution, stir, and transfer the above mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction; Step 3: After the reaction is complete, wash the mixture sequentially with distilled water, a distilled water-ethanol mixture, and ethanol by centrifugation. Pour off the supernatant, dry it in a vacuum oven, and grind it to obtain SnS2 / Nb2CT. x Heterojunction composite gas-sensitive materials.
[0009] The invention is further characterized in that, In step 1, the etching time is 24-48 hours; Nb2CT x The concentration of the solution is 0.03-3.33 mg / mL; the stirring rate is 300-800 r / min; and the stirring time is 30-120 min.
[0010] In step 2, the stirring rate is 500-800 r / min, the stirring time is 60-120 min, the reaction temperature is 160-220℃, and the reaction time is 12-24 h.
[0011] In step 2, Nb2CT x The mass ratio of tin tetrachloride and thiourea is 1-80:150-400:125-350.
[0012] In step 3, the drying temperature is 60-70℃ and the drying time is 12-24h.
[0013] The second technical solution adopted in this invention is SnS2 / Nb2CT. x SnS2 / Nb2CT prepared by the preparation method of heterojunction composite gas-sensitive material x Heterojunction composite gas-sensitive materials.
[0014] The third technical solution adopted in this invention is SnS2 / Nb2CT. x Application of heterojunction composite gas-sensitive materials in ammonia detection gas sensors. Specifically: SnS2 / Nb2CT... xHeterojunction composite gas-sensitive material is ground and mixed with ethanol or distilled water at a mass ratio of 1:3 to 10 to obtain SnS2 / Nb2CT. x Heterogeneous composite slurry; the slurry is coated onto the gas sensor body and dried to form a film.
[0015] The beneficial effects of this invention are: SnS2 / Nb2CT prepared in this invention x Heterojunction composite gas-sensitive materials possess a larger specific surface area, more active sites, and superior conductivity, providing efficient adsorption and reaction sites for NH3 molecules. They have significant research value and application significance in the field of ammonia gas sensors. Attached Figure Description
[0016] Figure 1 SnS2 / Nb2CT prepared for Example 1 of this invention x SEM characterization of heterojunction composite gas-sensitive materials; Figure 2 SnS2 / Nb2CT prepared for Example 2 of this invention x SEM characterization of heterojunction composite gas-sensitive materials; Figure 3 SnS2 / Nb2CT prepared in Example 3 of this invention x SEM characterization of heterojunction composite gas-sensitive materials; Figure 4 shows the sensitivity curves of the gas sensor prepared in this invention to 300 ppm ammonia at different temperatures; Figure 5 2 mg Nb2CT x Cyclic response curves of the SnS2 composite structure; Figure 6 1 mg Nb2CT x Response and recovery curves of the SnS2 composite structure to 300 ppm NH3; Figure 7 2 mg Nb2CT x Response and recovery curves of the SnS2 composite structure to 300 ppm NH3; Figure 8 18mg Nb2CT x Response and recovery curves of the SnS2 composite structure to 300 ppm NH3. Detailed Implementation
[0017] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.
[0018] This invention SnS2 / Nb2CT xThe preparation method of heterojunction composite gas-sensitive materials is carried out according to the following steps: Step 1: Using Nb2AlC powder as raw material, Nb2CT is obtained by etching with HF for 24-48 hours. x Powder; then Nb2CT x The powder was dispersed in distilled water and stirred to obtain Nb2CT. x Solution; Nb2CT x The concentration of the solution is 0.03-3.33 mg / mL; the stirring rate is 300-800 r / min; and the stirring time is 30-120 min. Step 2, to Nb2CT x Add tin tetrachloride and thiourea to the solution, stir, and transfer the above mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction; The stirring rate is 500-800 r / min, the stirring time is 60-120 min, the reaction temperature is 160-220℃, and the reaction time is 12-24 h.
[0019] Nb2CT x The mass ratio of tin tetrachloride and thiourea is 1-80:150-400:125-350; Step 3: After the reaction is complete, wash the product three times by centrifugation with distilled water, a distilled water-ethanol mixture, and ethanol in sequence. Pour off the supernatant and dry the resulting product in a vacuum oven to obtain a black substance. Grind the product to obtain SnS2 / Nb2CT. x Heterojunction composite gas-sensitive materials.
[0020] The drying temperature is 60-70℃, and the drying time is 12-24 hours; This invention SnS2 / Nb2CT x Application of heterojunction composite gas-sensitive materials in ammonia detection gas sensors, forming SnS2 / Nb2CT on the body of the ammonia detection gas sensor. x Heterogeneous composite coating, specifically: SnS2 / Nb2CT x Heterojunction composite gas-sensitive material is ground and mixed with ethanol or distilled water at a mass ratio of 1:3 to 10 to obtain SnS2 / Nb2CT. x Heterogeneous composite slurry; the slurry is coated onto the gas sensor body and dried at room temperature for 24 hours to form a film; Sensor body types include ceramic tube type devices and planar four-corner type devices; The coating method can be any one of brush coating, drip coating, or screen printing.
[0021] This sensor relies on SnS2 and Nb2CTx Synergistic effects of the resulting heterostructures: (a) Structurally, two-dimensional Nb2CT x (a) Providing a highly conductive framework and a large specific surface area to suppress lamellar aggregation, SnS2 grows uniformly on its surface, further increasing active sites; (b) At the electronic level, a built-in electric field is formed at the interface between the two, and electrons from the high Fermi level Nb2CT x (c) In terms of adsorption, Nb2CT rapidly transfers to SnS2, constructing an efficient electron transport channel, accelerating electron exchange during NH3 adsorption, and improving response speed and sensitivity; x The surface -OH and -F polar groups preferentially adsorb NH3 through hydrogen bonds. The charge transfer at the heterojunction interface can also enhance the adsorption strength and reduce the activation energy, enabling the material to respond efficiently at room temperature. The synergy of these three factors allows the composite material to achieve highly selective recognition of NH3, ultra-high sensitivity response and rapid response recovery, while also exhibiting excellent repeatability and stability.
[0022] The gas sensor of the present invention uses SnS2 / Nb2CT x The heterojunction composite gas-sensitive material serves as the core coating material, enabling stable operation at room temperature without the need for additional heating. Compared to pure Nb2CT... x And pure SnS2 material, SnS2 / Nb2CT x The heterojunction composite gas-sensitive material improves the detection sensitivity of NH3 by 2.49 times and 1.38 times, respectively, and has the characteristics of fast response, high stability and high selectivity, and can effectively resist the influence of interfering gases.
[0023] Example 1 This invention SnS2 / Nb2CT x The preparation method of heterojunction composite gas-sensitive materials is carried out according to the following steps: Nb2CT was obtained by etching Nb2AlC powder with HF for 24 hours. x Powder; Weigh 0.001 g Nb2CT x Dispersed in 30 mL of water, stirred at 500 r / min for 30 min, then 0.35 g of tin tetrachloride and 0.25 g of thiourea were added, and stirring continued for 120 min. The resulting mixture was transferred to a polytetrafluoroethylene reactor and reacted at 200 °C for 24 h. After removing the product, centrifugation and washing yielded a black precipitate, which was dried in a vacuum oven at 60 °C for 12 h. The final product was then ground to obtain SnS2 / Nb2CT. x Heterogeneous composite materials.
[0024] Example 2 SnS2 / Nb2CT x The preparation method of heterojunction composite gas-sensitive materials is as follows: Using Nb2AlC powder as raw material, Nb2CT was obtained by etching with HF for 30 hours. x Powder; weigh 0.002 g Nb2CT x The tin chloride and thiourea were dispersed separately in 30 mL of water and stirred at 500 r / min for 30 min. Then, 0.35 g of tin tetrachloride and 0.25 g of thiourea were added, and stirring continued for 120 min. The resulting mixed solution was transferred to a polytetrafluoroethylene reactor and reacted at 200 °C for 24 h. After removing the product, centrifugation and washing yielded a black precipitate, which was dried in a vacuum oven at 60 °C for 18 h. The final product was then ground to obtain SnS2 / Nb2CT. x Heterogeneous composite materials.
[0025] Example 3 SnS2 / Nb2CT x The preparation method of heterojunction composite gas-sensitive materials is as follows: Nb2AlC powder was used as raw material, and Nb2CT was obtained by etching with HF for 48 hours. x Powder; weigh 0.018 g Nb2CT x The tin chloride and thiourea were dispersed separately in 30 mL of water and stirred at 500 r / min for 30 min. Then, 0.35 g of tin tetrachloride and 0.25 g of thiourea were added, and stirring continued for 120 min. The resulting mixed solution was transferred to a polytetrafluoroethylene reactor and reacted at 200 °C for 24 h. After removing the product, centrifugation and washing yielded a black precipitate, which was dried in a vacuum oven at 70 °C for 12 h. The final product was then ground to obtain SnS2 / Nb2CT. x Heterogeneous composite materials.
[0026] Example 4 The SnS2 / Nb2CT prepared in the above examples was applied using a brush or drop coating method. x Heterojunction composite materials were coated onto the surface of ceramic tubular devices or planar quadrangular devices, and dried at room temperature for 24 hours to form a film, thus obtaining a series of gas sensors; the gas sensing performance of the sensors was tested using the CGS-8 gas sensing performance testing system; Figure 1-3 SnS2 / Nb2CT prepared for Examples 1-3 of this invention x SEM characterization images of the heterojunction composite gas-sensitive material show that SnS2 in Nb2CT x Surface growth. Nb2CT x Exhibiting an accordion-like layered structure, SnS2 exhibits a nanosheet-like layered structure, with SnS2 nanosheets mainly coating Nb2CT. x The resulting composite material has a large specific surface area and abundant active sites.
[0027] Figure 4 shows the Nb2CT prepared according to the present invention. x SnS2, 1 mg Nb2CT x SnS2 composite structure (SnS2 / Nb2CT) x -a), 2 mg Nb2CT x SnS2 composite structure (SnS2 / Nb2CT) x -b) and 18 mg Nb2CT x SnS2 composite structure (SnS2 / Nb2CT) x -c) Sensitivity histogram for 300 ppm ammonia. With the Nb2CT in the composite structure... x As the content of Nb2CT increases, the sensitivity of the composite material to NH3 first increases and then decreases. Specifically, 2 mg Nb2CT... x SnS2 composite structure (SnS2 / Nb2CT) x -b) It has the highest sensitivity to NH3, and is more sensitive to pure Nb2CT. x It is 2.49 times higher than that of pure SnS2 and 1.38 times higher than that of pure SnS2.
[0028] Figure 5 2 mg Nb2CT x Cyclic response curves of the SnS2 composite structure. The figure shows the Nb2CT... x The SnS2 composite structure exhibits excellent cycle stability.
[0029] Figure 6-8 For different concentrations of Nb2CT x The response and recovery curves of the SnS2 composite structure to 300 ppm NH3 are shown. The introduction of NH3 reduces the resistance, exhibiting N-type semiconductor characteristics, demonstrating that the synergistic effect of the heterojunction significantly enhances the ammonia sensitivity performance, fully showcasing the advantages of the composite material of this invention in the field of gas sensing.
[0030] Example 5 This invention SnS2 / Nb2CT x The preparation method of heterojunction composite gas-sensitive materials is carried out according to the following steps: Step 1: Using Nb2AlC powder as raw material, Nb2CT is obtained by etching with HF for 24 hours. x Powder; then Nb2CT x The powder was dispersed in distilled water and stirred to obtain Nb2CT. x Solution; Nb2CT x The concentration of the solution was 3 mg / mL; the stirring rate was 400 r / min; and the stirring time was 60 min. Step 2, to Nb2CT x Add tin tetrachloride and thiourea to the solution, stir, and transfer the above mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction; The stirring rate was 600 r / min, the stirring time was 100 min, the reaction temperature was 180 ℃, and the reaction time was 20 h.
[0031] Nb2CT x The mass ratio of tin tetrachloride and thiourea is 1:150:200; Step 3: After the reaction is complete, wash the product three times by centrifugation with distilled water, a distilled water-ethanol mixture, and ethanol in sequence. Pour off the supernatant and dry the resulting product in a vacuum oven at 70°C for 12 hours to obtain a black substance. Grind the product to obtain SnS2 / Nb2CT. x Heterojunction composite gas-sensitive materials.
[0032] Example 6 This invention SnS2 / Nb2CT x The preparation method of heterojunction composite gas-sensitive materials is carried out according to the following steps: Step 1: Using Nb2AlC powder as raw material, Nb2CT is obtained by etching with HF for 48 hours. x Powder; then Nb2CT x The powder was dispersed in distilled water and stirred to obtain Nb2CT. x Solution; Nb2CT x The concentration of the solution was 3.33 mg / mL; the stirring rate was 800 r / min; and the stirring time was 30 min. Step 2, to Nb2CT x Add tin tetrachloride and thiourea to the solution, stir, and transfer the above mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction; The stirring rate was 800 r / min, the stirring time was 60 min, the reaction temperature was 220℃, and the reaction time was 12 h.
[0033] Nb2CT x The mass ratio of tin tetrachloride and thiourea is 10:200:300; Step 3: After the reaction is complete, wash the product three times by centrifugation with distilled water, a distilled water-ethanol mixture, and ethanol in sequence. Pour off the supernatant and dry the resulting product in a vacuum oven at 70°C for 14 hours to obtain a black substance. Grind the product to obtain SnS2 / Nb2CT. x Heterojunction composite gas-sensitive materials.
[0034] Example 7 This invention SnS2 / Nb2CT xThe preparation method of heterojunction composite gas-sensitive materials is carried out according to the following steps: Step 1: Using Nb2AlC powder as raw material, Nb2CT is obtained by etching with HF for 24 hours. x Powder; then Nb2CT x The powder was dispersed in distilled water and stirred to obtain Nb2CT. x Solution; Nb2CT x The concentration of the solution was 3 mg / mL; the stirring rate was 300 r / min; and the stirring time was 60 min. Step 2, to Nb2CT x Add tin tetrachloride and thiourea to the solution, stir, and transfer the above mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction; The stirring rate was 800 r / min, the stirring time was 120 min, the reaction temperature was 160 ℃, and the reaction time was 12 h.
[0035] Nb2CT x The mass ratio of tin tetrachloride and thiourea is 10:150:350; Step 3: After the reaction is complete, wash the product three times by centrifugation with distilled water, a distilled water-ethanol mixture, and ethanol in sequence. Pour off the supernatant and dry the resulting product in a vacuum oven to obtain a black substance. Grind the product to obtain SnS2 / Nb2CT. x Heterojunction composite gas-sensitive materials.
[0036] The drying temperature is 60℃ and the drying time is 24 hours.
[0037] This invention SnS2 / Nb2CT x Heterojunction composite gas-sensitive materials can be applied to ammonia detection gas sensors. These sensors operate stably at room temperature without the need for additional heating devices, and combine rapid response, ultra-high detection sensitivity, and excellent stability, significantly reducing energy consumption and operating costs. Leveraging the synergistic effect of the heterojunction, compared to pure Nb2CT… x Compared with pure SnS2 material, this composite material improves the detection sensitivity of NH3 by 2.49 times and 1.38 times, respectively, while significantly optimizing the selective recognition ability of ammonia and effectively resisting the influence of other interfering gases in the environment. This invention has broad application prospects and promotional value in the fields of industrial exhaust gas monitoring, agricultural and aquaculture environmental management, and indoor air quality testing.
Claims
1. SnS2 / Nb2CT x The method for preparing heterojunction composite gas-sensitive materials is characterized by, The specific steps are as follows: Step 1: Using Nb2AlC powder as raw material, Nb2CT is obtained by HF etching. x Powder; then Nb2CT x The powder was dispersed in distilled water and stirred to obtain Nb2CT. x Solution; Step 2, to Nb2CT x Add tin tetrachloride and thiourea to the solution, stir, and transfer the above mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction; Step 3: After the reaction is complete, wash the mixture sequentially with distilled water, a distilled water-ethanol mixture, and ethanol by centrifugation. Pour off the supernatant, dry it in a vacuum oven, and grind it to obtain SnS2 / Nb2CT. x Heterojunction composite gas-sensitive materials.
2. The SnS2 / Nb2CT as described in claim 1 x The method for preparing heterojunction composite gas-sensitive materials is characterized by, In step 1, the etching time is 24-48 hours; Nb2CT x The concentration of the solution is 0.03-3.33 mg / mL; the stirring rate is 300-800 r / min; and the stirring time is 30-120 min.
3. The SnS2 / Nb2CT as described in claim 1 x The method for preparing heterojunction composite gas-sensitive materials is characterized by, In step 2, the stirring rate is 500-800 r / min, the stirring time is 60-120 min, the reaction temperature is 160-220℃, and the reaction time is 12-24 h.
4. The SnS2 / Nb2CT as described in claim 1 x The method for preparing heterojunction composite gas-sensitive materials is characterized by, In step 2, Nb2CT x The mass ratio of tin tetrachloride and thiourea is 1-80:150-400:125-350.
5. The SnS2 / Nb2CT as described in claim 1 x The method for preparing heterojunction composite gas-sensitive materials is characterized by, In step 3, the drying temperature is 60-70℃ and the drying time is 12-24h.
6. The SnS2 / Nb2CT as described in any one of claims 1-5 x SnS2 / Nb2CT prepared by the preparation method of heterojunction composite gas-sensitive material x Heterojunction composite gas-sensitive materials.
7. The SnS2 / Nb2CT as described in any one of claims 1-5 x Application of heterojunction composite gas-sensitive materials in ammonia detection gas sensors.
8. The application as described in claim 7, characterized in that, Specifically, this involves: SnS2 / Nb2CT x Heterojunction composite gas-sensitive material is ground and mixed with ethanol or distilled water at a mass ratio of 1:3 to 10 to obtain SnS2 / Nb2CT. x Heterogeneous composite slurry; the slurry is coated onto the gas sensor body and dried to form a film.