A kind of acetone gas sensor based on PtRu alloy modified hollow spherical ZnFe2O4, preparation method and application thereof
By modifying hollow spherical ZnFe2O4 nanomaterials with PtRu alloy, the problems of low sensitivity and poor selectivity in acetone detection of existing gas sensors are solved, realizing the practical application of a high-sensitivity, low-cost acetone gas sensor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2026-03-17
- Publication Date
- 2026-06-09
AI Technical Summary
Existing gas sensors have low sensitivity and poor selectivity in acetone detection, making it difficult to achieve rapid and accurate detection. They are also costly and difficult to widely adopt.
Hollow spherical ZnFe2O4 nanomaterials were modified with PtRu alloy. Hollow ZnFe2O4 microspheres were prepared by hydrothermal and co-reduction methods, and PtRu alloy nanocrystals were loaded on their surface to form a Schottky barrier to improve the sensitivity and selectivity of the sensor.
It improves the sensor's sensitivity and selectivity to acetone, lowers the detection limit, and shortens the response recovery time, making it suitable for mass production and miniaturized applications.
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Figure CN122171629A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor oxide gas sensor technology, specifically relating to an acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4, its preparation method, and its application in acetone gas detection. Background Technology
[0002] Acetone, a colorless, highly volatile organic compound gas, is classified as a hazardous chemical due to its significant toxicity and flammability. Long-term exposure to acetone concentrations exceeding 300 ppm can cause multi-system damage to the body. Acetone has important value in medical diagnostics, being a byproduct of human metabolism, and its exhaled concentration is closely related to blood glucose metabolism. Under normal physiological conditions, the acetone concentration in the exhaled breath of healthy individuals remains at a low level, typically between 0.3 and 0.9 ppm. However, the acetone concentration in the exhaled breath of diabetic patients is significantly elevated, often exceeding 1.8 ppm. This characteristic makes acetone a key biomarker for diabetes screening and disease monitoring. Therefore, achieving rapid, accurate, and real-time detection of various harmful gases has crucial practical significance and broad application prospects.
[0003] Currently, methods for detecting acetone gas mainly include chemical analysis, gas chromatography, mass spectrometry, and Fourier transform infrared spectroscopy. However, these methods are lengthy, involve expensive instruments, and are cumbersome to operate, hindering their widespread adoption. Gas sensors, on the other hand, offer advantages such as simple structure, low cost, and ease of operation, and are easily miniaturized and integrated, demonstrating significant application potential in environmental monitoring, industrial safety, and medical diagnostics. However, in practical applications, sensors face challenges such as low sensitivity, poor selectivity, and insufficient adaptability. Therefore, developing novel gas sensors with high sensitivity, high selectivity, good stability, and low power consumption has become a research hotspot in the field of gas sensing. Summary of the Invention
[0004] The purpose of this invention is to provide an acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4, its preparation method, and its application in acetone gas detection.
[0005] This invention modifies the semiconductor material ZnFe2O4 with PtRu alloy, thereby increasing the sensitivity of the gas sensor, shortening the sensor's recovery time, and lowering the sensor's detection limit, thus promoting the practical application of this type of sensor in the field of gas detection.
[0006] The present invention discloses an acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4, comprising an Al2O3 ceramic tube substrate with two parallel, annular, and discrete gold electrodes on its outer surface, a nano-sensitive material coated on the outer surface of the Al2O3 ceramic tube and the gold electrodes, and a nickel-chromium alloy heating coil placed inside the Al2O3 ceramic tube; the nano-sensitive material is a bimetallic PtRu alloy-modified hollow spherical ZnFe2O4, and it is prepared by the following steps:
[0007] (1) Dissolve 0.1~0.2g zinc nitrate hexahydrate and 0.4~0.6g ferric nitrate hexahydrate in a mixed solvent of 8~10g glycerol and 30~40mL isopropanol, and stir magnetically for 4~5h; then transfer the mixed solution to a 100mL stainless steel autoclave lined with Teflon, and hydrothermally react at 160~180°C for 20~30h; after cooling to room temperature, wash the reaction product alternately with deionized water and anhydrous ethanol several times, dry the product, and then heat it to 450~500°C at a heating rate of 2~3°C / min, and calcine it for 1.5~3.0h to obtain hollow spherical ZnFe2O4 sensitive material;
[0008] (2) Mix 0.1-0.2 mmol of ruthenium trichloride, 0.1-0.2 mmol of platinum acetylacetonate, 40-50 mg of ascorbic acid and 40-50 mg of polyvinylpyrrolidone in 10-12 mL of ethylene glycol, stir magnetically for 30-40 minutes, and heat in an oil bath at 160-170°C for 2-3 hours; cool to room temperature, wash the precipitate with acetone and anhydrous ethanol by ultrasonic shaking and centrifugation several times, and disperse the product in 10-15 mL of ethanol to obtain a bimetallic PtRu alloy nanocrystal ethanol dispersion;
[0009] (3) 50 mg of the ZnFe2O4 sensitive material obtained in step (1) was ultrasonically dispersed in 10-15 mL of anhydrous ethanol, and 0.03-0.09 mL of the bimetallic PtRu alloy nanocrystal ethanol dispersion obtained in step (2) was added to it. The mixture was ultrasonically dispersed for 30-60 minutes. The mass of the PtRu alloy nanocrystals was 0.3-0.7% of the mass of ZnFe2O4. The mixture was then dried overnight at 60-70°C to obtain the hollow spherical ZnFe2O4 sensitive material modified with PtRu alloy.
[0010] The hollow spherical ZnFe2O4 sensing material modified with PtRu alloy prepared in this invention consists of hollow microspheres with a diameter of 1~1.5μm. The bimetallic PtRu alloy is modified on the surface of the hollow spherical ZnFe2O4, and the PtRu nanoparticles have a size of about 3nm. Due to the different work functions of PtRu and ZnFe2O4, electron transfer occurs between them, forming a Schottky barrier, which increases the baseline resistance of the sensor, thus improving its response to gases.
[0011] The method for preparing an acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4 according to the present invention comprises the following steps:
[0012] (1) Mix 10-20 mg of hollow spherical ZnFe2O4 sensitive material modified with PtRu alloy with 1-3 mL of deionized water in a mortar. Then, use a small brush to evenly coat the resulting mixture solution onto the outer surface of an Al2O3 ceramic tube with a diameter of 3.5-4.5 mm, an outer diameter of 1.1-1.3 mm, and an inner diameter of 0.7-0.9 mm, and cover it with gold electrodes. The width of the gold electrodes is 0.35-0.45 mm, and the distance between the two gold electrodes is 0.4-0.6 mm. Then bake it under an infrared lamp for 8-15 minutes. Then sinter the Al2O3 ceramic tube at 250-350℃ for 1.5-3.0 hours to improve its mechanical strength.
[0013] (2) The sintered Al2O3 ceramic tube is welded onto a hexagonal base, and a 30-40 ohm nickel-chromium heating wire is inserted into the Al2O3 ceramic tube as a heater. The working temperature of the sensor is controlled by adjusting the current through the nickel-chromium heating wire. Finally, the sensor is aged at 200-300℃ for 5-10 days to obtain the acetone gas sensor based on PtRu alloy modified hollow spherical ZnFe2O4 described in this invention.
[0014] The acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4 prepared in this invention has the following advantages:
[0015] 1. Hollow ZnFe2O4 microspheres and PtRu alloy nanocrystals can be prepared using simple hydrothermal and co-reduction methods. Then, an acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4 can be prepared. This synthesis method is simple and low in cost.
[0016] 2. ZnFe2O4 has a hollow microsphere morphology, and its large specific surface area can provide more reaction sites. Due to the synergistic effect of bimetals, better gas-sensing performance can be obtained with a smaller bimetal loading, which is beneficial to improving the utilization rate of the catalyst and reducing the cost.
[0017] 3. This invention uses a commercially available tubular sensor, which has a simple manufacturing process, small size, and is suitable for mass production. Attached Figure Description
[0018] Figure 1 (a) is a TEM image of PtRu alloy nanocrystals; Figure 1 (b) is a high-resolution TEM image of PtRu alloy nanocrystals; Figure 1(c) TEM image of 0.5wt% PtRu-ZnFe2O4; Figure 1 (d) is a high-resolution TEM image of 0.5wt% PtRu-ZnFe2O4;
[0019] like Figure 1 As shown, the PtRu alloy nanocrystals are uniformly dispersed without obvious agglomeration, and have a diameter of 2-4 nm. The lattice fringes of approximately 0.222 nm correspond to the (111) plane of PtRu, proving that the presence of Ru can alter the lattice spacing of Pt. The ZnFe2O4 microspheres have a diameter of approximately 1-1.5 μm, and the lattice spacing indicates that PtRu was successfully supported on ZnFe2O4.
[0020] Figure 2 Sensitive materials for ZnFe2O4, 0.3wt% PtRu-ZnFe2O4, 0.5wt% PtRu-ZnFe2O4 and 0.7wt% PtRu-ZnFe2O4 20 o ~80 o XRD patterns within the range and XRD standard card patterns of ZnFe2O4 materials;
[0021] like Figure 2 As shown, the diffraction peaks of all samples correspond to standard card No. 82-1049, proving that the synthesized ZnFe2O4 samples have high purity. However, no diffraction peaks corresponding to Pt or Ru were observed in the PtRu-ZnFe2O4 sensitive material, which may be due to the small particle size of the PtRu alloy nanocrystals and insufficient loading.
[0022] Figure 3 The operating temperature-sensitivity curves of sensors based on ZnFe2O4, 0.3wt% PtRu-ZnFe2O4, 0.5wt% PtRu-ZnFe2O4 and 0.7wt% PtRu-ZnFe2O4 sensitive materials are shown. The sensitivity is defined as: Sensitivity = Resistance between two gold electrodes in air / Resistance between two gold electrodes in acetone.
[0023] like Figure 3As shown, all sensors exhibited good responses to 100 ppm acetone gas at temperatures ranging from 180 to 220 °C. It can be observed that the sensitivity initially increases and then gradually decreases with increasing temperature. The ZnFe₂O₄ loaded with 0.5 wt% PtRu showed a sensitivity as high as 364 at 200 °C, 3.34 times that of pure ZnFe₂O₄, indicating that the synergistic effect of PtRu nanoparticles can improve gas sensing performance. Clearly, the gas sensing performance of the sensor improves with increasing PtRu loading. However, the sensitivity of the sensor based on 0.7% PtRu-ZnFe₂O₄ sensitive material decreased, possibly due to agglomeration caused by excessive PtRu.
[0024] Figure 4 (a) is the response recovery curve of pure ZnFe2O4 to 100ppm acetone at 210℃; Figure 4 (b) is the response recovery curve of 0.5wt%PtRu-ZnFe2O4 to 100ppm acetone at 200℃;
[0025] like Figure 4 As shown, the response time of 0.5wt% PtRu-ZnFe2O4 material to 100ppm acetone at 200℃ is 2 seconds and the recovery time is 222 seconds. It can be seen that after loading PtRu alloy nanocrystals, the response and recovery times of the material are reduced by 1 second and 97 seconds, respectively, which proves the strong catalytic activity of PtRu alloy nanocrystals.
[0026] Figure 5 Repeatability curve of 0.5wt% PtRu-ZnFe2O4 at 200℃ against 100ppm acetone;
[0027] like Figure 5 As shown, the response curve of the 0.5wt% PtRu-ZnFe2O4 sensor did not change significantly during ten repeated exposures to 100ppm acetone gas, indicating that the sensor has good repeatability.
[0028] Figure 6 (a) is the sensitivity curve of pure ZnFe2O4 to different concentrations of acetone at 210℃; Figure 6 (b) is the sensitivity curve of 0.5wt% PtRu-ZnFe2O4 to different concentrations of acetone at 200℃;
[0029] like Figure 6As shown, the sensitivity of both sensors gradually increases with increasing concentration. The 0.5wt% PtRu-ZnFe2O4 material exhibits a sensitivity of 1.5 for acetone concentrations as low as 50 ppb at 200℃, while pure ZnFe2O4 material cannot detect this concentration, demonstrating the application potential of the sensor described in this invention in the detection of low-concentration acetone.
[0030] Figure 7 Selectivity histograms of ZnFe2O4 and 0.5wt% PtRu-ZnFe2O4 for 100ppm gas at their respective optimal operating temperatures;
[0031] like Figure 7 As shown, the sensitive material loaded with PtRu alloy exhibits excellent selectivity. Among them, 0.5wt%PtRu-ZnFe2O4 has a much higher sensitivity to acetone gas than to other gases, proving that the sensor has good selectivity to acetone gas. Detailed Implementation
[0032] Example 1
[0033] (1) Dissolve 0.149 g zinc nitrate hexahydrate and 0.404 g ferric nitrate nonahydrate in a mixed solvent of 10 g glycerol and 36 mL isopropanol and stir magnetically for 5 hours; transfer the resulting mixture to a 100 mL Teflon-lined stainless steel autoclave and hydrothermally react in an oven at 180 °C for 24 hours; after naturally cooling to room temperature, wash the resulting precipitate with deionized water and anhydrous ethanol 6 times in sequence, dry the product in an oven at 60 °C overnight, and then heat it to 500 °C in a muffle furnace at a heating rate of 2 °C / min and calcine it for 2 hours to obtain hollow spherical ZnFe2O4 sensitive material;
[0034] (2) Dissolve 50 mg polyvinylpyrrolidone, 50 mg ascorbic acid, 0.1 mmol ruthenium trichloride and 0.1 mmol platinum acetylacetonate in 10 mL ethylene glycol, stir magnetically for 30 minutes until completely dissolved, and then heat in an oil bath at 160 °C for 3 hours. After cooling to room temperature, wash the precipitate four times with acetone and anhydrous ethanol by ultrasonic vibration and centrifugation. Disperse the product in 10 mL ethanol to obtain a bimetallic PtRu alloy nanocrystal ethanol dispersion.
[0035] Then, its concentration was measured: a small glass slide was placed on a balance and its mass was weighed; 20 μL of the bimetallic PtRu alloy nanocrystal ethanol dispersion was dropped onto the glass slide with a pipette, and its mass was weighed again after the ethanol evaporated. The process was repeated several times and the average value was taken to obtain the concentration of the PtRu alloy nanocrystal ethanol dispersion as 4.4 mg / mL.
[0036] (3) 50 mg of the ZnFe2O4 sensitive material obtained in step (1) was ultrasonically dispersed in 10 mL of anhydrous ethanol, and 0.057 mL of the bimetallic PtRu alloy nanocrystal ethanol dispersion obtained in step (2) was added dropwise to the above mixture. After ultrasonication for 30 minutes, the mass of the PtRu alloy nanocrystal was 0.5% of the mass of ZnFe2O4. The mixture was then dried overnight in an oven at 60 °C to obtain hollow spherical ZnFe2O4 material modified with PtRu alloy, labeled as 0.5 wt% PtRu-ZnFe2O4.
[0037] 4. Mix 10 mg of PtRu alloy nanocrystal-modified ZnFe2O4 material with 2 mL of deionized water in a mortar until homogeneous. Then, use a small brush to evenly coat the mixture onto the outer surface of an Al2O3 ceramic tube with a length of 4 mm, an outer diameter of 1.2 mm, and an inner diameter of 0.8 mm, and cover it with gold electrodes. The width of the gold electrodes is 0.40 mm, and the distance between the two gold electrodes is 0.5 mm. Then, bake it under an infrared lamp for 10 minutes. After the moisture evaporates, sinter the Al2O3 ceramic tube in a muffle furnace at 300 °C for 2 hours to improve its mechanical strength.
[0038] 5. The sintered Al2O3 ceramic tube is welded onto a hexagonal base, and a 35-ohm nickel-chromium heating wire is inserted inside the Al2O3 ceramic tube as a heater. The working temperature of the sensor is controlled by adjusting the current passing through the nickel-chromium heating wire. Finally, the sensor is aged at 250℃ for 5 days to obtain an acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4.
[0039] Example 2
[0040] ZnFe₂O₄ nanomaterials and PtRu alloy nanocrystals were prepared according to the method in Example 1, with the mixing ratio of the two varied. 0.034 mL of PtRu ethanol dispersion was mixed with 10 mL of anhydrous ethanol solution containing 50 mg ZnFe₂O₄. The mass of the PtRu alloy nanocrystals in the prepared device was 0.3% of the mass of ZnFe₂O₄, labeled as 0.3 wt% PdtRu-ZnFe₂O₄. The device preparation and testing methods were consistent with those in Example 1.
[0041] Example 3
[0042] ZnFe₂O₄ nanomaterials and PtRu alloy nanocrystals were prepared according to the method in Example 1, with the mixing ratio of the two varied. 0.080 mL of PtRu ethanol dispersion was mixed with 10 mL of anhydrous ethanol solution containing 50 mg ZnFe₂O₄. The mass of the PtRu alloy nanocrystals in the prepared device was 0.7% of the mass of ZnFe₂O₄, labeled as 0.7 wt% PtRu-ZnFe₂O₄. The device preparation and testing methods were consistent with those in Example 1.
[0043] Comparative Example 1
[0044] Pure-phase ZnFe2O4 nanomaterials were prepared according to the aforementioned method, i.e., steps (2) and (3) were omitted. The device preparation method and testing method were the same as in Example 1.
Claims
1. An acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4, comprising an Al2O3 ceramic tube substrate with two parallel, annular, and discrete gold electrodes on its outer surface, nano-sensitive materials coated on the outer surface of the Al2O3 ceramic tube and the gold electrodes, and a nickel-chromium alloy heating coil placed inside the Al2O3 ceramic tube; characterized in that: The nano-sensitive material is a bimetallic PtRu alloy-modified hollow spherical ZnFe2O4, and it is prepared by the following steps. (1) Dissolve 0.1~0.2g zinc nitrate hexahydrate and 0.4~0.6g ferric nitrate hexahydrate in a mixed solvent of 8~10g glycerol and 30~40mL isopropanol, and stir magnetically for 4~5h; then react the mixed solution hydrothermally at 160~180 °C for 20~30h; after cooling to room temperature, wash the reaction product alternately with deionized water and anhydrous ethanol several times, dry the product, heat it to 450~500°C at a heating rate of 2~3°C / min, and calcine it for 1.5~3.0h to obtain hollow spherical ZnFe2O4 sensitive material; (2) Mix 0.1-0.2 mmol of ruthenium trichloride, 0.1-0.2 mmol of platinum acetylacetonate, 40-50 mg of ascorbic acid and 40-50 mg of polyvinylpyrrolidone in 10-12 mL of ethylene glycol, stir magnetically for 30-40 minutes, and heat in an oil bath at 160-170°C for 2-3 hours; cool to room temperature, wash the precipitate with acetone and anhydrous ethanol by ultrasonic shaking and centrifugation several times, and disperse the product in 10-15 mL of ethanol to obtain a bimetallic PtRu alloy nanocrystal ethanol dispersion; (3) 50 mg of the ZnFe2O4 sensitive material obtained in step (1) was ultrasonically dispersed in 10-15 mL of anhydrous ethanol, and 0.03-0.09 mL of the bimetallic PtRu alloy nanocrystal ethanol dispersion obtained in step (2) was added to it. The mixture was ultrasonically dispersed for 30-60 minutes. The mass of the PtRu alloy nanocrystals was 0.3-0.7% of the mass of ZnFe2O4. The mixture was then dried overnight at 60-70°C to obtain the hollow spherical ZnFe2O4 sensitive material modified with PtRu alloy.
2. The preparation method of the acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4 according to claim 1, the steps of which are as follows: (1) Mix 10-20 mg of hollow spherical ZnFe2O4 sensitive material modified with PtRu alloy with 1-3 mL of deionized water in a mortar. Then, use a small brush to evenly coat the resulting mixture solution on the outer surface of the Al2O3 ceramic tube and cover it with gold electrodes. Then, bake it under an infrared lamp for 8-15 minutes. Then, sinter the Al2O3 ceramic tube at 250-350℃ for 1.5-3.0 hours to improve its mechanical strength. (2) The sintered Al2O3 ceramic tube is welded onto a hexagonal base, and a nickel-chromium heating wire is inserted into the Al2O3 ceramic tube as a heater. The working temperature of the sensor is controlled by adjusting the current passing through the nickel-chromium heating wire. Finally, the sensor is aged at 200~300℃ for 5~10 days to obtain an acetone gas sensor based on hollow spherical ZnFe2O4 modified with PtRu alloy.
3. The method for preparing an acetone gas sensor based on PtRu alloy-modified hollow spherical ZnFe2O4 as described in claim 1, characterized in that: The Al2O3 ceramic tube has a length of 3.5~4.5mm, an outer diameter of 1.1~1.3mm, and an inner diameter of 0.7~0.9mm; the gold electrode has a width of 0.35~0.45mm, and the distance between the two gold electrodes is 0.4~0.6mm.