An antimonate composite material based on a heterostructure junction and preparation and application thereof

Abstract

The application belongs to the technical field of gas sensors, and particularly relates to a stibinate composite material based on a heterostructure junction and preparation and application thereof. x Mg 1‑x Sb2O6 or a stibinate / titanium dioxide composite Ni x Mg 1‑x Sb2O6 / TiO2 as a sensitive material, and a n-propanol gas sensor is prepared. At an optimal working temperature, the response value of the sensor to 20 ppm n-propanol reaches above 35, the detection limit is as low as 20 ppb, and the sensor has excellent selectivity, and has great potential in environmental monitoring, industrial production and early screening of diseases through breath analysis.

Description

Technical Field

[0001] This invention belongs to the field of gas sensor technology, specifically relating to an antimonate composite material based on heterogeneous isomorphism and its preparation and application. Background Technology

[0002] Volatile organic compounds (VOCs) have a significant impact on human health. Short-term exposure to certain concentrations of VOCs can cause varying degrees of discomfort such as dizziness, headaches, nausea, and dry heaving. Prolonged exposure can cause varying degrees of damage to internal organs and the nervous system, and in severe cases, can even lead to shock and death. n-Propanol, a typical VOC gas, is widely used in the production of paints, cosmetics, and pharmaceuticals. Exposure to high concentrations of n-propanol gas can cause respiratory illnesses, drowsiness, headaches, central nervous system depression, and carries a carcinogenic risk. Furthermore, some typical VOCs have been identified as biomarkers for specific diseases. For example, analysis of breath samples from lung cancer patients revealed an average n-propanol concentration of approximately 500 ppb, far exceeding the concentration in normal human breath. Therefore, developing advanced n-propanol gas sensors with high response, high selectivity, and low detection limits is of great significance for environmental monitoring, industrial production, and early disease screening through breath analysis.

[0003] Titanium dioxide (TiO2) is a polycrystalline metal oxide. Rutile TiO2, in particular, possesses advantages such as structural stability, high catalytic performance, and a unique electronic structure, making it widely used in photocatalysis, solar cells, and gas sensing. However, pure TiO2 materials still suffer from low response, weak selectivity, and high detection limits in gas sensing applications, making it difficult to meet the demands for high response, strong selectivity, and low detection limits for target gases in environmental monitoring, industrial production, and especially breath diagnostics. Antimonate materials are still in the early stages of application in gas sensors, with few reports. Constructing heterojunctions is a typical strategy to enhance gas sensing performance. The conductivity type and band structure of the material are frequently considered factors when constructing heterojunctions, but the crystal structure receives less attention. Summary of the Invention

[0004] This invention proposes a heterostructure-based antimonate composite material, its synthesis method, and its application in gas detection. The sensor prepared by this invention uses the heterostructure-based antimonate composite material as the sensitive material, exhibiting advantages such as high response, excellent selectivity, low detection limit, good repeatability, and long-term stability. It can achieve high-performance detection of typical volatile organic compounds and has great potential for environmental monitoring, industrial production, and early disease screening based on breath analysis.

[0005] This invention discloses a heterogeneous isomorphic antimonate composite material, which is a composite material containing antimonate and having a heterogeneous isomorphic structure; the composite material is a bimetallic antimonate Ni containing Ni and Mg. x Mg 1-x Sb₂O₆, where 0 < x < 1; or Ni composed of antimonate and titanium dioxide. x Mg 1-x Sb₂O₆ / TiO₂ complex, where 0 ≤ x ≤ 1;

[0006] When x=0, the composite material is a complex of MgSb2O6 / TiO2, which is composed of Mg-containing monometallic antimonate MgSb2O6 and titanium dioxide.

[0007] When x=1, the composite material is a composite of NiSb2O6 / TiO2, which is composed of Ni-containing monometallic antimonate NiSb2O6 and titanium dioxide.

[0008] When 0 < x < 1, the antimonate is a bimetallic antimonate containing Ni and Mg. x Mg 1-x Sb₂O₆, in this case, the composite material may or may not contain titanium dioxide; if it contains titanium dioxide, the composite material is a complex of bimetallic antimonate and titanium dioxide. Ni x Mg 1-x Sb₂O₆ / TiO₂; if titanium dioxide is not present, the composite material is a bimetallic antimonate Ni. x Mg 1-x Sb2O6.

[0009] Heteroisomeric structures are formed in bimetallic antimonates and in composites of antimonates and titanium dioxide.

[0010] Heteromorphic isomorphism refers to an interfacial structure in composite materials formed by the close contact and bonding of different materials with identical (or highly similar) crystal structures at the microscopic scale. In bimetallic antimonate composites, heteromorphic isomorphism is composed of NiSb₂O₆ and MgSb₂O₆, two different substances belonging to the rutile phase; in monometallic antimonate / titanium dioxide composites, it is composed of rutile phase MgSb₂O₆ or NiSb₂O₆ and rutile phase TiO₂, two materials belonging to the tetragonal crystal system and P42 / mnm space group, with highly similar and related crystal structures; in bimetallic antimonate / titanium dioxide composites, it is composed of rutile phase NiSb₂O₆ or NiSb₂O₆ and rutile phase TiO₂, two materials belonging to the tetragonal crystal system and P42 / mnm space group, with highly similar and related crystal structures; in bimetallic antimonate / titanium dioxide composites, it is composed of rutile phase NiSb₂O₆ or NiSb₂O₆. x Mg 1-x Sb₂O₆ and rutile TiO₂ are two materials that belong to the tetragonal crystal system and the P42 / mnm space group, and are highly similar and related in crystal structure.

[0011] The present invention discloses a method for preparing antimonate composite materials based on heterostructure, comprising the following:

[0012] The preparation method of antimonate includes the following steps: dissolving nickel acetate and / or magnesium acetate in ethanol, adding antimony trichloride and triethylamine, mixing well, and reacting at 140℃~180℃ for 10h~20h. After the reaction is completed, heat treatment is performed at 600℃~800℃ for 1h~3h to obtain antimonate Ni. x Mg 1-x Sb₂O₆, 0≤x≤1;

[0013] Add nickel acetate, magnesium acetate, and antimony trichloride according to the stoichiometric ratio;

[0014] When only nickel acetate is added, NiSb2O6, a monometallic antimonate containing Ni, is obtained, in which case x=1;

[0015] When only magnesium acetate is added, a monometallic antimonate MgSb2O6 containing Mg is obtained, at which point x=0;

[0016] When nickel acetate and magnesium acetate are added simultaneously, a bimetallic antimonate Ni is obtained. x Mg 1-x Sb₂O₆, where 0 < x < 1.

[0017] The preparation method of the antimonate / titanium dioxide composite includes the following steps: reacting a titanium-based metal-organic framework, antimonate, and polyvinylpyrrolidone in ethanol using a solvothermal method; followed by heat treatment after the reaction is complete to obtain the composite material Ni. x Mg 1-x Sb2O6 / TiO2.

[0018] The mass ratio of titanium-based metal-organic framework to antimonate is 40:1 to 10:1. The reaction temperature is 140℃ to 180℃, and the reaction time is 2h to 10h; the heat treatment temperature is 600℃ to 800℃, and the heat treatment time is 1h to 3h.

[0019] The preparation method of titanium-based metal-organic frameworks includes the following steps: tetrabutyl titanate and terephthalic acid are added to a mixed solvent of N,N-dimethylformamide and methanol, mixed thoroughly, and reacted at 140℃~180℃ for 16h~24h to obtain titanium-based metal-organic frameworks. The molar ratio of tetrabutyl titanate to terephthalic acid is 1:2~1:4, and the volume ratio of N,N-dimethylformamide to methanol is 9:1~1:1.

[0020] This invention discloses an antimonate composite material based on heterogeneous isomorphism, which can be used as a sensing material for a n-propanol gas sensor. The method of use includes the following: a pair of annular gold electrodes are attached to a ceramic tube, each annular gold electrode having two conductive platinum wires led out and welded to the base pins respectively; a nickel-chromium alloy heating wire passes through the ceramic tube and is welded to the remaining two pins of the base; a slurry made of antimonate composite material and ethanol is coated on the surface of the ceramic tube, and aged at 0.3W~0.5W for 24h~48h to obtain the n-propanol gas sensor with antimonate composite material.

[0021] The sensor is connected to the test system and placed in the atmosphere to be tested. The gas-sensitive performance of the sensor is characterized by the response value, where response value = R. a / R g , where R a R is the resistance value of the sensor in air. g This represents the resistance value of the sensor in the target gas atmosphere.

[0022] The beneficial effects of this invention are:

[0023] This invention provides for the first time a gas sensor based on heterostructured antimonate nanocomposites. Using bimetallic antimonates, monometallic antimonate / titanium dioxide, and bimetallic antimonate / titanium dioxide with heterostructured structures as sensing materials, it exhibits better selectivity and repeatability for n-propanol compared to monometallic antimonate and titanium dioxide materials. Metallic antimonates M(II)Sb₂O₆ (M = Ni, Mg) are a class of multi-metal oxides with a unique trirutile structure. Due to Sb... 5+ The high charge density alters the bond length and bond angle between Sb and oxygen, resulting in a distorted Sb-O structure that exposes more active sites. Furthermore, the synergistic effect between metal ions and the Sb-O polyhedron further enhances the catalytic performance of the material.

[0024] Among them, bimetallic antimonate Ni with heterostructure isomorphism 0.9 Mg 0.1 The response of Sb₂O₆ to 20 ppm n-propanol is 2.22 times and 8.09 times that of monometallic antimonate NiSb₂O₆ and MgSb₂O₆, respectively; the response of monometallic antimonate / titanium dioxide composite NiSb₂O₆ / TiO₂ to 20 ppm n-propanol is 4.71 times and 2.64 times that of monometallic antimonate NiSb₂O₆ and TiO₂, respectively; the response of bimetallic antimonate / titanium dioxide composite NiSb₂O₆ / TiO₂ is... 0.9 Mg 0.1 The response of Sb₂O₆ / TiO₂ to 20 ppm n-propanol is 6.48 times that of the monometallic antimonate NiSb₂O₆ and 3.64 times that of TiO₂. The detection limit for n-propanol decreases from 0.1 ppm for NiSb₂O₆ and TiO₂ to that of NiSb₂O₆. 0.9Mg 0.1 0.05 ppm of Sb₂O₆, NiSb₂O₆ / TiO₂ and Ni 0.9 Mg 0.1 0.02 ppm of Sb2O6 / TiO2.

[0025] This invention utilizes the characteristic of different materials having the same (or highly similar) structure in crystal structure to construct a heteromorphic composite material. Thanks to the similar lattice constants and similar atomic layouts between different materials, the heteromorphic composite has a lower lattice mismatch rate and higher electron transport performance, which improves the gas-sensing performance of the material. It can meet the high-performance requirements of gas sensors with high response, strong selectivity and low detection limit in fields such as environmental monitoring, industrial production and breath diagnosis.

[0026] In summary, compared to monometallic antimonates and titanium dioxide, bimetallic antimonates and antimonate / titanium dioxide composites with heterostructures exhibit significantly improved gas-sensing performance, specifically characterized by a markedly higher response value, significantly improved selectivity, a substantial reduction in the detection limit, and excellent repeatability. Therefore, constructing heterostructures is an effective strategy for enhancing gas-sensing performance. Furthermore, the solvothermal method employed in this invention offers advantages such as low cost, simple preparation process, flexible reaction parameter settings, and good repeatability. Attached Figure Description

[0027] Figure 1 The images show comparisons between the XRD spectra of the materials prepared in the embodiments and comparative examples of the present invention and the standard PDF cards; wherein, (a) are Examples 1-2 and Comparative Examples 1-2, and (b) are Examples 3-5 and Comparative Example 3.

[0028] Figure 2 The graph shows a comparison of the response values ​​of various gas sensors to n-propanol at different temperatures when the concentration of n-propanol is 20 ppm; where (a) represents Examples 1-2 and Comparative Examples 1-2, and (b) represents Examples 3-5 and Comparative Examples 1 and 3.

[0029] Figure 3 The graph shows the response of each gas sensor to different gases.

[0030] Figure 4 The graphs show the response curves of each gas sensor to different concentrations of n-propanol at the optimal temperature; where (a) is Comparative Example 1, (b) is Example 1, (c) is Example 2, (d) is Comparative Example 3, (e) is Example 3, (f) is Example 4, and (g) is Example 5.

[0031] Figure 5The graphs show the response cycle test curves of each gas sensor to 20 ppm n-propanol at the optimal temperature; where (a) is Comparative Example 1, (b) is Comparative Example 3, (c) is Example 1, (d) is Example 2, (e) is Example 3, (f) is Example 4, (g) is Example 5, and (h) is the response value.

[0032] Figure 6 This is a schematic diagram of the structure of the sensor prepared according to the present invention; wherein, (a) is the overall structure and (b) is a partial enlarged view; 1-pin, 2-base, 3-nickel-chromium alloy heating wire, 4-ceramic tube, 5-ring gold electrode, 6-sensing material.

[0033] Figure 7 The image shows a physical view of the sensor prepared according to the present invention; wherein, (a) is a front view and (b) is a top view. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. It should be noted that the embodiments described in this invention are only for further explanation and illustration, and not for limiting their application scope. Based on this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention.

[0035] First, we prepared monometallic antimonates NiSb2O6 and MgSb2O6, as well as titanium-based metal-organic frameworks MIL-125(Ti) and its derived TiO2 nanosheets. This can be used to prepare for the preparation of composite materials and also as a comparative example to compare the performance of composite materials.

[0036] Comparative Example 1

[0037] Preparation of NiSb2O6:

[0038] (1) Dissolve 1 mmol of nickel acetate and 2 mmol of antimony trichloride in 30 mL of anhydrous ethanol and stir continuously until homogeneous. Then add 1 mL of triethylamine and denote it as solution A.

[0039] (2) Pour solution A into the inner liner of a 50 mL reactor, place it in an oven and react at 160 °C for 16 h. After natural cooling, wash with anhydrous ethanol and collect by centrifugation. After drying, calcine the obtained precipitate in air at 700 °C for 2 h to obtain the monometallic antimonate NiSb2O6.

[0040] Comparative Example 2

[0041] Preparation of MgSb2O6:

[0042] (1) Dissolve 1 mmol of magnesium acetate and 2 mmol of antimony trichloride in 30 mL of anhydrous ethanol and stir continuously until homogeneous. Then add 1 mL of triethylamine and denote it as solution B.

[0043] (2) Pour solution B into the inner liner of a 50 mL reactor, place it in an oven and react at 160 °C for 16 h. After natural cooling, wash with anhydrous ethanol and collect by centrifugation. After drying, calcine the obtained precipitate in air at 700 °C for 2 h to obtain monometallic antimonate MgSb2O6.

[0044] Comparative Example 3

[0045] Preparation of titanium-based metal-organic frameworks MIL-125(Ti) and TiO2 nanosheets:

[0046] 3.32 g of terephthalic acid was dissolved in 60 mL of a mixed solvent of N,N-dimethylformamide and methanol. 1.7 mL of tetrabutyl titanate was added while stirring at room temperature. After stirring for 1 h, the solution was poured into a reaction vessel and placed in an oven at 150 °C for 20 h. After cooling, the mixture was washed with ethanol, centrifuged, collected, and dried to obtain the titanium-based metal-organic framework MIL-125(Ti).

[0047] Titanium-based metal-organic frameworks were calcined at high temperature in air (700°C) for 2 hours to obtain rutile TiO2 nanosheets.

[0048] Example 1

[0049] Ni 0.9 Mg 0.1 Synthesis of Sb2O6 composite materials:

[0050] 0.9 mmol of nickel acetate and 0.1 mmol of magnesium acetate were added sequentially to 30 mL of ethanol solvent, followed by 2 mmol of antimony chloride and 1 mL of triethylamine. After stirring thoroughly at room temperature, the mixture was poured into a reaction vessel and reacted at 160 °C for 16 h. After the reaction was completed and the reaction vessel was cooled to room temperature, the resulting precipitate was washed with ethanol, collected by centrifugation, and dried. Finally, it was calcined at 700 °C for 2 h to obtain Ni with heterogeneous homogeneous structure. 0.9 Mg 0.1 Sb2O6 composite material.

[0051] Example 2

[0052] Ni 0.7 Mg 0.3 Synthesis of Sb2O6 composite materials:

[0053] 0.7 mmol of nickel acetate and 0.3 mmol of magnesium acetate were added sequentially to 30 mL of ethanol solvent, followed by 2 mmol of antimony chloride and 1 mL of triethylamine. After stirring thoroughly at room temperature, the mixture was poured into a reaction vessel and reacted at 160 °C for 16 h. After the reaction was completed and the reaction vessel was cooled to room temperature, the resulting precipitate was washed with ethanol, collected by centrifugation, and dried. Finally, it was calcined at 700 °C for 2 h to obtain Ni with heterogeneous homogeneous structure. 0.7 Mg 0.3 Sb2O6 composite material.

[0054] Example 3

[0055] Synthesis of NiSb2O6 / TiO2-2 composite material:

[0056] 0.02 g of NiSb₂O₆ was dispersed in 30 mL of ethanol, and 0.5 g of polyvinylpyrrolidone (K30) was added, followed by 0.4 g of MIL-125(Ti). After stirring continuously at room temperature until homogeneous, the solution was poured into a reaction vessel and placed in an oven at 160 °C for 5 h. After the reaction was completed, the precipitate was washed, centrifuged, and dried, and then calcined at 700 °C for 2 h to obtain a NiSb₂O₆ / TiO₂⁻ composite material with heterogeneous homogeneous structure.

[0057] Example 4

[0058] Synthesis of NiSb2O6 / TiO2-4 composite material:

[0059] 0.04 g of NiSb₂O₆ was dispersed in 30 mL of ethanol, and 0.5 g of polyvinylpyrrolidone (K30) was added, followed by 0.4 g of MIL-125 (Ti). After stirring continuously at room temperature until homogeneous, the solution was poured into a reaction vessel and placed in an oven at 160 °C for 5 h. After the reaction was completed, the precipitate was washed, centrifuged, and dried, and then calcined at 700 °C for 2 h to obtain a NiSb₂O₆ / TiO₂⁻⁴ composite material with heterogeneous homogeneous structure.

[0060] Example 5

[0061] Ni 0.9 Mg 0.1 Synthesis of Sb2O6 / TiO2 composite material:

[0062] Take 0.01g Ni 0.9 Mg 0.1Sb₂O₆ was dispersed in 30 mL of ethanol, and 0.5 g of polyvinylpyrrolidone (K₃₀) was added, followed by 0.4 g of MIL-125 (Ti). After continuous stirring at room temperature until homogeneous, the solution was poured into a reaction vessel and placed in an oven at 160 °C for 5 h. After the reaction, the resulting precipitate was washed, centrifuged, and dried, and then calcined at 700 °C for 2 h to obtain Ni with a heterogeneous homogeneous junction. 0.9 Mg 0.1 Sb2O6 / TiO2 composite material.

[0063] The prepared material was characterized, and the results are as follows:

[0064] Depend on Figure 1 (a) It can be seen that the XRD characteristics of Comparative Examples 1 and 2 are highly consistent with those of NiSb₂O₆ (PDF No.: 38-1083) and MgSb₂O₆ (PDF No.: 37-1420), respectively, and the corresponding crystal form is trirutile phase, with space group P42 / mnm (space group number: 136), indicating that pure NiSb₂O₆ and MgSb₂O₆ were successfully synthesized. In addition, no other impurity peaks were found in the XRD characteristic peaks of Examples 1 and 2, indicating that Ni with heterostructure was synthesized. x Mg 1-x Sb₂O₆ composite material. (The text appears to be incomplete and contains several grammatical errors. Figure 1 (b) It can be seen that the XRD characteristic peaks of Comparative Example 3 highly match those of rutile TiO2 (PDF No.: 21-1276), with space group P42 / mnm (space group number: 136). The XRD patterns of Examples 3-4 simultaneously show characteristic peaks corresponding to both rutile TiO2 and NiSb2O6, indicating the successful synthesis of a monometallic antimonate / titanium dioxide composite material (NiSb2O6 / TiO2) with heterogeneous isomorphism. The XRD spectrum of Example 5 does not show characteristic peaks other than those of NiSb2O6, MgSb2O6, and rutile TiO2, indicating the successful synthesis of a bimetallic antimonate / titanium dioxide composite material (NiSb2O6 / TiO2). x Mg 1-x Sb2O6 / TiO2).

[0065] The materials prepared in each embodiment and comparative example were used as sensing materials to fabricate a n-propanol gas sensor, and the specific methods are as follows:

[0066] The gas sensor consists of pins 1, base 2, nickel-chromium alloy heating wire 3, ceramic tube 4, ring-shaped gold electrode 5, and sensing material 6. The overall structure is as follows: Figure 6 As shown in (a), a magnified view of the sensing part is as follows: Figure 6 As shown in (b). A physical image is shown below. Figure 7 (a) and Figure 7 As shown in (b).

[0067] The specific preparation method is as follows: prepare a sensor base with six pins, a ceramic tube with a pair of ring-shaped gold electrodes, and lead out two conductive platinum wires and one nickel-chromium alloy heating wire from each ring-shaped gold electrode, as well as the sensing material prepared above.

[0068] (1) Assemble the gas sensor: Weld the ceramic tube to the sensor base, weld the conductive platinum wire to the four pins and connect it to the test circuit, and weld the two ends of the nickel-chromium alloy heating wire through the ceramic tube to the remaining two pins of the sensor base to connect the heating circuit.

[0069] (2) Coating gas-sensitive materials: Take an appropriate amount of the sensing materials prepared in each example and comparative example and a certain amount of ethanol to make a slurry. Use a pipette to take an appropriate amount of slurry and drop it onto the ceramic tube. Rotate quickly to coat the material evenly on the surface of the ceramic tube to obtain gas sensors with different sensing materials.

[0070] (3) After coating, place it on a heating table and age it at 0.3W~0.5W for 24h~48h to improve the stability of the sensor in preparation for subsequent gas-sensitive tests.

[0071] The prepared sensor was connected to the test system and placed in the atmosphere to be tested. The gas-sensitive sensing performance was characterized by the response value, where response value = R. a / R g , where R a R is the resistance value of the sensor in air. g This represents the resistance value of the sensor in the target gas atmosphere.

[0072] The gas-sensing performance of each prepared sensor was tested, and the results are as follows:

[0073] Using n-propanol as the target gas, the gas-sensing properties of the proposed heterostructured antimonate composite material were analyzed. Figure 2 (a) It can be seen that Comparative Examples 1-2 and Examples 1-2 all showed the highest response value to n-propanol at 320°C. Among them, Examples 1-2 (bimetallic antimonate) showed a much higher response to n-propanol at the optimal operating temperature (320°C) than Comparative Examples 1 and 2. Example 1 performed the best, with a response of 12.06 to 20 ppm n-propanol at 320°C, which is 2.22 times and 8.09 times that of Comparative Examples 1 and 2, respectively.

[0074] Depend on Figure 2(b) It can be seen that the optimal operating temperatures for n-propanol in Comparative Example 3 and Examples 3-5 are 240°C, 260°C, 260°C and 240°C, respectively. The response of Examples 3-5 to n-propanol at their respective optimal operating temperatures is significantly improved compared with Comparative Example 3. Specifically, the response of Example 3 (monometallic antimonate / titanium dioxide composite material) to 20 ppm n-propanol at 260°C reaches 25.55, which is 4.71 and 2.64 times that of Comparative Example 1 and Comparative Example 3, respectively. The response of Example 5 (bimetallic antimonate / titanium dioxide composite material) to 20 ppm n-propanol at 240°C reaches 35.19, which is 6.48 and 3.64 times that of Comparative Example 1 and Comparative Example 3, respectively.

[0075] The test results above demonstrate that constructing heterogeneous isomorphic structures from different materials with the same or highly similar crystal structures can significantly improve the gas-sensing performance of the materials. This applies to materials with similar chemical formulas (such as the bimetallic antimonate composites of Examples 1 and 2 based on NiSb₂O₆ and MgSb₂O₆), materials with different chemical formulas (such as the monometallic antimonate / titanium dioxide composites of Examples 3 and 4 based on NiSb₂O₆ and TiO₂), and even composites of multiple components (such as the bimetallic antimonate / titanium dioxide composite of Example 5 based on NiSb₂O₆, MgSb₂O₆, and TiO₂). All these materials exhibit a gain effect during gas-sensing testing. This is because although the designed basic components are heterogeneous (i.e., each component is a different substance), they are also isomorphic (i.e., each component belongs to the same space group and crystal system, and has similar lattice constants). Constructing heterogeneous isomorphic structures at the interface allows for higher lattice matching and lower lattice mismatch rates, which is beneficial for carrier migration and transport, resulting in a significant improvement in gas-sensing performance.

[0076] Depend on Figure 3It can be seen that Examples 1-5, at their respective optimal temperatures of 320℃, 320℃, 260℃, 260℃, and 240℃, all exhibited excellent selectivity for n-propanol, with responses to n-propanol significantly higher than those to gases including benzene, toluene, methanol, styrene, methyl ethyl ketone (MEK), acetone, and isopropanol. The types and concentrations of the detection atmosphere are as follows: n-propanol 20 ppm, benzene 100 ppm, toluene 100 ppm, methanol 20 ppm, styrene 20 ppm, MEK 20 ppm, acetone 20 ppm, and isopropanol 20 ppm. Among them, the response of Example 1 to 20 ppm n-propanol at the optimal operating temperature was 6.79 times, 4.16 times, 2.17 times, 2.85 times, 1.62 times, 1.83 times, and 1.45 times that of the above detection atmosphere, respectively; the response of Example 3 to 20 ppm n-propanol at the optimal operating temperature was 14.19 times, 10.8 times, 9.9 times, 10.41 times, 1.8 times, 4.2 times, and 3.55 times that of the above detection atmosphere, respectively; and the response of Example 5 to 20 ppm n-propanol at the optimal operating temperature was 26.76 times, 19.71 times, 13.1 times, 11.97 times, 1.92 times, 5.49 times, and 4.92 times that of the above detection atmosphere, respectively.

[0077] Depend on Figure 4 As shown, by Figure 4 (a) and Figure 4 (b) It can be seen that, compared with Comparative Example 1, the detection limit of n-propanol in Example 1 was significantly reduced, from 0.1 ppm in Comparative Example 1 to 0.05 ppm in Example 1, and the corresponding response value increased from 1.38 in Comparative Example 1 to 1.59 in Example 1; Figure 4 (c) It can be seen that although the detection limit of Example 2 remains at 0.1 ppm, the corresponding response value has increased to 2.03. Figure 4 (d) shows that the detection limit for n-propanol in Comparative Example 3 is 0.1 ppm; Figure 4 (e) Figure 4 (f) and Figure 4 (g) As can be seen, compared with Comparative Example 3, the detection limits for n-propanol in Examples 3-5 decreased significantly, all to 0.02 ppm, with corresponding response values ​​of 1.33, 1.23, and 1.68, respectively. The detection limits for n-propanol in Examples 1-5 are much lower than the content of n-propanol in the exhaled breath of lung cancer patients, which can meet the low detection limit requirement for early disease screening and has great potential for achieving early disease screening through breath analysis.

[0078] Figure 5 (a) is Comparative Example 1. Figure 5 (b) is Comparative Example 3. Figure 5 (c) is Example 1. Figure 5 (d) is Example 2. Figure 5 (e) is Example 3. Figure 5 (f) is Example 4. Figure 5 (g) is the resistivity diagram of five consecutive tests on 20 ppm n-propanol in Example 5. The similar response-recovery curves indicate that each sensor exhibits excellent repeatability in five consecutive tests on 20 ppm n-propanol at its optimal operating temperature. Figure 5 (h) It can be seen that the responses of Example 1 to 20 ppm n-propanol in five consecutive tests were 12.14, 12.38, 12.30, 11.97, and 12.21, respectively; the responses of Example 2 to 20 ppm n-propanol in five consecutive tests were 8.82, 8.95, 8.82, 8.73, and 8.62, respectively; and the responses of Example 3 to 20 ppm n-propanol in five consecutive tests were 25.95, 26.58, 26.02, 25.74, and 25. .22, The responses of five consecutive tests of 20 ppm n-propanol in Example 4 were 23.10, 22.88, 22.21, 22.49 and 22.70, respectively. The responses of five consecutive tests of 20 ppm n-propanol in Example 5 were 35.67, 35.28, 34.97, 34.27 and 35.22, respectively. The variances of the five consecutive test response values ​​of each sensor were 0.025, 0.015, 0.242, 0.118 and 0.269, respectively.

[0079] Finally, it is worth noting that the above examples are merely specific embodiments of the present invention, meaning that the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this invention should be considered within the scope of protection of this invention.

Claims

1. An antimonate composite material based on heterostructure, characterized in that, The composite material, used as the sensing material for the n-propanol gas sensor, has a heterogeneous isomorphic structure and is composed of Ni consisting of antimonate and titanium dioxide. x Mg 1-x Sb2O6 / TiO2 complex, 0 < x < 1; The preparation method of the composite material includes the following steps: dissolving magnesium acetate and nickel acetate in ethanol, adding antimony trichloride and triethylamine, mixing and reacting, and then heat-treating after the reaction is complete to obtain antimonate Ni. x Mg 1-x Sb₂O₆; Titanium-based metal-organic frameworks, antimonate, and polyvinylpyrrolidone were reacted in ethanol using a solvothermal method, followed by heat treatment to obtain Ni. x Mg 1-x Sb2O6 / TiO2 complex.

2. The method for preparing an antimonate composite material based on heterostructure as described in claim 1, characterized in that, The process includes the following steps: dissolving magnesium acetate and nickel acetate in ethanol, adding antimony trichloride and triethylamine, mixing thoroughly, and reacting at 140℃~180℃ for 10h~20h. After the reaction is complete, heat treatment is performed at 600℃~800℃ for 1h~3h to obtain antimonate Ni. x Mg 1-x Sb₂O₆, 0 < x < 1; Titanium-based metal-organic frameworks, antimonate, and polyvinylpyrrolidone were reacted in ethanol using a solvothermal method. After the reaction was completed, heat treatment was performed to obtain the composite material Ni. x Mg 1-x Sb2O6 / TiO2.

3. The method for preparing an antimonate composite material based on heterostructure according to claim 2, characterized in that, The mass ratio of the titanium-based metal-organic framework to antimonate is 40:1 to 10:1, the reaction temperature is 140℃ to 180℃, and the reaction time is 2h to 10h; the heat treatment temperature after the solvothermal reaction is 600℃ to 800℃, and the heat treatment time is 1h to 3h.

4. The method for preparing an antimonate composite material based on heterostructure according to claim 2, characterized in that, The preparation method of the titanium-based metal-organic framework includes the following steps: adding tetrabutyl titanate and terephthalic acid to a mixed solvent of N,N-dimethylformamide and methanol, mixing well, and reacting at 140℃~180℃ for 16h~24h to obtain the titanium-based metal-organic framework.

5. The method for preparing an antimonate composite material based on heterostructure according to claim 4, characterized in that, The molar ratio of tetrabutyl titanate to terephthalic acid is 1:2 to 1:4, and the volume ratio of N,N-dimethylformamide to methanol is 9:1 to 1:

1.

6. The application of the antimonate composite material based on heterogeneous isomorphism as described in claim 1, characterized in that, The composite material is used for n-propanol gas detection, including the following: a pair of annular gold electrodes are attached to a ceramic tube, a conductive platinum wire is led out from the annular gold electrodes and welded to the base pins, and a nickel-chromium alloy heating wire passes through the ceramic tube and is welded to other pins of the base; a slurry made of antimonate composite material and ethanol is coated on the surface of the ceramic tube to obtain an n-propanol gas sensor with antimonate composite material. The sensor is connected to the test system and placed in the atmosphere to be tested. The gas-sensitive sensor performance is characterized by the response value, where response value = R. a / R g , where R a R is the resistance value of the sensor in air. g The resistance value of the sensor in the target gas atmosphere.

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