A method for preparing europium ferrite nanosensors and their applications
Europium ferrite nanosensors prepared by electrospinning and low-temperature calcination processes solve the problems of complexity and applicability of existing ethylene detection methods, and achieve simple, low-cost and highly selective ethylene detection results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANSHUI NORMAL UNIV
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-30
AI Technical Summary
Existing ethylene detection methods are complex to operate, costly, and have poor applicability, making it difficult to achieve rapid response and high selectivity under various environmental conditions.
Europium ferrite nanosensors with hollow nanotube structures and high concentrations of oxygen vacancy defects were fabricated by electrospinning combined with low-temperature confined domain calcination for the detection of ethylene gas.
It achieves easy operation, low cost, rapid response and high selectivity for ethylene detection under various environmental conditions, thus improving detection performance.
Smart Images
Figure CN122301271A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of gas sensor technology, specifically relating to a method for preparing europium ferrite nanosensors and their applications. Background Technology
[0002] Ethylene is an organic compound, a colorless gas with a slight odor, and is highly volatile at room temperature and pressure. While it does not have direct and strong toxic effects on humans, high concentrations can pose a risk of asphyxiation. Furthermore, ethylene is flammable and explosive, posing certain dangers. Due to the presence of double bonds in its molecular structure, it is chemically reactive and readily undergoes polymerization and addition reactions. Therefore, ethylene plays a crucial role in chemical production, commonly used as a primary raw material for producing plastics such as polyethylene and polyvinyl chloride, and is also widely used in synthetic rubber, synthetic fibers, pharmaceuticals, and dyes. Given its widespread industrial applications and potential hazards, accurate and reliable detection of ethylene content is essential. Additionally, as a plant hormone, it is also important in monitoring fruit ripening.
[0003] The existing methods for detecting ethylene mainly include gas chromatography, photoionization detection, and infrared spectroscopy, which are described below: Gas chromatography (GC): This method utilizes the differences in partition coefficients between the gas and stationary phases to separate mixtures using a chromatographic column, and then quantitatively detects ethylene using detectors (such as FID or TCD). It offers advantages such as high sensitivity, strong resolution, and good repeatability. However, it requires specialized technicians and a high level of expertise, and it cannot directly analyze unknown substances or provide direct qualitative analysis; comparison with known substances or data and corresponding chromatographic peaks is necessary.
[0004] Photoionization detection (PID): This method detects ethylene molecules based on the principle of ionization under ultraviolet light. PID detectors selectively respond to ethylene molecules, reflecting the concentration of ethylene by measuring the intensity of the electron flow generated after ionization. While it offers fast response and a low detection limit, its accuracy is not very high and it is not suitable for long-term continuous monitoring.
[0005] Infrared spectroscopy: This method determines ethylene content by detecting the infrared spectrum of a sample, offering advantages such as low cost and speed. However, it cannot accurately monitor samples with low ethylene content and is easily affected by environmental factors.
[0006] Those skilled in the art aim to develop an ethylene detection solution that is easy to operate, low in cost, widely applicable, adaptable to various environmental conditions, and has rapid response and high selectivity. Summary of the Invention
[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing europium ferrite nanosensors and their applications. This method, through controlling the electrospinning and calcination processes, prepares hollow nanotubes with abundant oxygen vacancies, significantly improving the detection performance of ethylene gas.
[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for fabricating europium ferrite nanosensors, comprising the following steps: electrospinning combined with low-temperature confined domain calcination to in-situ construct hollow nanotube structures with high concentrations of oxygen vacancy defects. Step 1: Dissolve 0.28g-0.45g of Eu(NO3)3·6H2O and 0.25g-0.40g of Fe(NO3)3·9H2O in 2.2ml-3.2ml of DMF to form a metal salt solution; simultaneously, dissolve 0.25g-0.35g of PVP in 1.5ml-2.5ml of anhydrous ethanol to form a polymer solution; mix the metal salt solution and the polymer solution, and stir at a constant temperature of 25℃-35℃ for 3.5h-4.5h. Utilize the coordination and crosslinking effect between PVP molecular chains and metal ions to regulate the solution viscosity, thereby obtaining a homogeneous reddish-brown spinning precursor solution. Step 2: The spinning precursor liquid is placed in an electrospinning device and spinning is carried out under the conditions of applying a voltage of 11.5kV, receiving distance of 15cm to 25cm, and feed flow rate of 5.0 to 6.0μl / min. Eu / Fe / PVP composite precursor fibers are obtained on the receiving device. Step 3: The composite precursor fiber is calcined at a temperature range of 550℃ to 700℃ for 1.5h to 2.0h. During this process, the kinetic difference between the thermal decomposition rate of PVP and the grain growth rate of metal oxides is utilized to induce the formation of EuFeO3 hollow nanotube structures inside the fiber. Simultaneously, by limiting the maximum calcination temperature, complete repair of lattice oxygen is suppressed, and 34.0% to 35.0% of vacant oxygen (O2) is retained in situ in the nanotube surface lattice. v )defect; Step 4: Pre-install 4 platinum wires at both ends of the alumina ceramic tube, and insert a nickel-chromium alloy coil into the alumina ceramic tube as a heating wire. Weld the two ends of the platinum wires and the heating wire to the electrode posts in sequence to form the sensor substrate. Step 5: Place the prepared EuFeO3 nanotubes in a container, add deionized water, and grind and disperse to form a suspension homogenate. Use a coating process to uniformly coat the homogenate onto the surface of the sensor substrate. Step 6: Dry the coated sensor at room temperature, and then place it in an aging chamber at 180℃~220℃ for 36h~48h to obtain the europium ferrite nanotube gas sensor.
[0009] Preferably, the outer diameter of the EuFeO3 hollow nanotubes ranges from 200 nm to 220 nm, and the tube walls are formed by the accumulation of nanoparticles and exhibit a porous and rough morphology.
[0010] Preferably, the europium ferrite nanotube gas sensor is used to detect ethylene, especially low concentrations of ethylene released during fruit ripening.
[0011] The beneficial effects of this invention are as follows: (1) In this invention, europium ferrite (EuFO3) nanotubes were synthesized by electrospinning using chemicals such as Eu(NO3)3·6H2O, Fe(NO3)3·9H2O, PVP, DMF, deionized water, and anhydrous ethanol. Then, europium ferrite (EuFO3) powder was coated onto a sensor to detect the content of ethylene. The preparation process is simple and the sensor has high sensitivity, providing a new way to detect ethylene.
[0012] (2) Through characterization tests such as Figure 1 The SEM images shown in (a) and (b) illustrate the europium ferrite (EuFO3) samples prepared in this experiment, which are nanotubes. These nanotubes are intertwined to form a large number of pores. Figure 1 (a) and (b) clearly show the rough surface of the nanotubes. These rough surface properties allow europium ferrite (EuFO3) nanomaterials to have a larger specific surface area, thus providing more adsorption sites for oxygen ions and optimizing their gas detection performance. Figure 2 For TEM testing, the clear fringes confirmed that europium ferrite (EuFO3) has good crystallinity. The prepared europium ferrite (EuFO3) was characterized by X-ray diffraction (XRD), and its structure, crystal phase, and chemical composition were analyzed. Figure 3 As shown, we can observe that the diffraction peaks are very strong and sharp, indicating that the prepared sample has good crystallinity. All the characteristic peaks of the pretreatment are highly consistent with the standard europium ferrite (EuFO3) PDF card (PDF#74-1475). The characteristic peaks of the synthesized europium ferrite (EuFO3) nanomaterials are obviously prominent, with no other impurity peaks, and the crystal purity is excellent. XRD shows that a relatively pure europium ferrite (EuFO3) sample has been successfully prepared.
[0013] (3) To further determine the valence state and surface chemical composition of the samples in this invention, X-ray photoelectron spectroscopy (XPS) characterization analysis was performed, such as... Figure 4 As shown. The binding energy of the entire spectrum was characterized and analyzed using the C 1s peak (position 284.80 eV), as shown. Figure 4 (a) shows the characteristic spectral lines of C 1s; the high-resolution spectrum of Fe 2p is as follows. Figure 4As shown in (b), the two spectral lines of the Fe 2p state splitting are Fe 2p 1 / 2 and Fe 2p 3 / 2 These correspond to 723.87 eV and 710.67 eV respectively, with a splitting energy of 13.20 eV; Figure 4 (c) is the high-resolution spectrum of Eu3d, with peaks at 1135.43 eV and 1165.17 eV corresponding to Eu3d5 / 2 and Eu3d3 / 2, respectively; Figure 4 (d) shows the fine 1s spectrum of O, with the three peaks at 529.48 eV, 531.68 eV, and 533.96 eV representing lattice oxygen (O₂). L ), vacant oxygen (O) V ) and adsorbed oxygen (O C ), vacant oxygen (O V The presence of oxygen vacancies can provide a large amount of reaction space and active sites on the material surface. In europium ferrite (EuFO3) nanomaterials, the proportion of vacant oxygen is 34.44%, which provides a large amount of reaction space and more effective active sites for the adsorption and reaction of ethylene gas molecules. Attached Figure Description
[0014] Figure 1 The image shown is a SEM image of EuFO3 in Example 8. Figure 2 The image shown is a TEM image of EuFO3 in Example 8. Figure 3 The image shown is the XRD pattern of EuFO3 in Example 8. Figure 4 (a)-(d) are the XPS characteristic curves of C 1s, Fe 2p, Eu 3d, and O 1s in Example 8, respectively; Figure 5 (a), (c), and (e) are the sensing characteristic curves of EuFO3 in Example 8 for ethylene gas released by different types of fruits; (b), (d), and (f) are the response diagrams of EuFO3 in Example 1 for ethylene gas released by different types of fruits. Detailed Implementation
[0015] Example 1 0.28 g of Eu(NO3)3·6H2O and 0.25 g of Fe(NO3)3·9H2O were dissolved in 2.2 ml of DMF, respectively, and stirred at 1200 rpm for 0.5 h at 25 °C. Simultaneously, 0.25 g of PVP was dissolved in 1.5 ml of anhydrous ethanol and stirred at 25 °C for 1.5 h. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 1200 rpm for 3.5 h at 25 °C to obtain a homogeneous reddish-brown solution. This solution was then loaded into a 10 ml plastic syringe, with the distance between the metal tip and the collecting plate set to 15 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 5.0 μl / min. The collected nanotubes were then annealed at 550 °C for 1.5 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was then dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 180°C for 48 hours to achieve optimal stability.
[0016] Example 2 0.45 g of Eu(NO3)3·6H2O and 0.40 g of Fe(NO3)3·9H2O were dissolved in 3.2 ml of DMF, respectively, and stirred at 1200 rpm for 1.5 h at 35 °C. Simultaneously, 0.35 g of PVP was dissolved in 2.5 ml of anhydrous ethanol and stirred at 35 °C for 2.5 h. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 1200 rpm for 4.5 h at 35 °C to obtain a homogeneous reddish-brown solution. This solution was then loaded into a 15 ml plastic syringe, with the distance between the metal tip and the collecting plate set to 25 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 6.0 μl / min. The collected nanotubes were then annealed at 700 °C for 2 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was then dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 200°C for 45 hours to achieve optimal stability.
[0017] Example 3 0.323 g of Eu(NO3)3·6H2O and 0.356 g of Fe(NO3)3·9H2O were dissolved in 3.0 mL of DMF and stirred at 1200 rpm for 1.5 h at 30 °C. Simultaneously, 0.25 g of PVP was dissolved in 2.5 mL of anhydrous ethanol and stirred at 26 °C for 1.5 h. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 1200 rpm for 3.5 h at 35 °C to obtain a homogeneous reddish-brown solution. This solution was then loaded into a 10 mL plastic syringe, with the distance between the metal tip and the collecting plate set to 18 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 5.0 μl / min. The collected nanotubes were then annealed at 600 °C for 2 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was then dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 210°C for 40 hours to achieve optimal stability.
[0018] Example 4 0.312 g of Eu(NO3)3·6H2O and 0.343 g of Fe(NO3)3·9H2O were dissolved in 2.4 ml of DMF, respectively, and stirred at 1200 rpm for 0.5 h at 35 °C. Simultaneously, 0.32 g of PVP was dissolved in 2.2 ml of anhydrous ethanol and stirred at 30 °C for 1.8 h. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 1200 rpm for 4 h at 25 °C to obtain a homogeneous reddish-brown solution. This solution was then filled into a 10 ml plastic syringe, with the distance between the metal tip and the collecting plate set to 22 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 6.0 μl / min. The collected nanotubes were then annealed at 700 °C for 1.5 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was then dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 220°C for 36 hours to achieve optimal stability.
[0019] Example 5 0.299 g of Eu(NO3)3·6H2O and 0.312 g of Fe(NO3)3·9H2O were dissolved in 2.3 mL of DMF, respectively, and stirred at 1200 rpm for 1.2 h at 25 °C. Simultaneously, 0.30 g of PVP was dissolved in 2.1 mL of anhydrous ethanol and stirred at 28 °C for 2 h. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 1200 rpm for 4.5 h at 25 °C to obtain a homogeneous reddish-brown solution. This solution was then loaded into a 10 mL plastic syringe, with the distance between the metal tip and the collecting plate set to 23 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 5.3 μl / min. The collected nanotubes were then annealed at 550 °C for 2 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 190°C for 43 hours to achieve optimal stability.
[0020] Example 6 0.400 g of Eu(NO3)3·6H2O and 0.386 g of Fe(NO3)3·9H2O were dissolved in 3.0 ml of DMF and stirred at 1200 rpm for 1.5 h at 33 °C. Simultaneously, 0.35 g of PVP was dissolved in 2.5 ml of anhydrous ethanol and stirred at 32 °C for 1.5 h. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 1200 rpm for 4 h at 30 °C to obtain a homogeneous reddish-brown solution. This solution was then filled into a 15 ml plastic syringe, with the distance between the metal tip and the collecting plate set to 20 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 5.5 μl / min. The collected nanotubes were then annealed at 700 °C for 2 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was then dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 220°C for 45 hours to achieve optimal stability.
[0021] Example 7 0.374 g of Eu(NO3)3·6H2O and 0.318 g of Fe(NO3)3·9H2O were dissolved in 2.2 ml of DMF, respectively, and stirred at 1200 rpm for 1.5 h at 32 °C. Simultaneously, 0.28 g of PVP was dissolved in 2.4 ml of anhydrous ethanol and stirred at 28 °C for 2 h. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 1200 rpm for 4.5 h at 25 °C to obtain a homogeneous reddish-brown solution. This solution was then loaded into a 10 ml plastic syringe, with the distance between the metal tip and the collecting plate set to 18 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 5.8 μl / min. The collected nanotubes were then annealed at 650 °C for 1.5 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was then dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 195°C for 39 hours to achieve optimal stability.
[0022] Example 8 0.356 g of Eu(NO3)3·6H2O and 0.323 g of Fe(NO3)3·9H2O were dissolved in 2.5 ml of DMF, respectively, and stirred at 1200 rpm for 1 h at 26 °C. Simultaneously, 0.27 g of PVP was dissolved in 2 ml of anhydrous ethanol and stirred at 1200 rpm for 2 h at 30 °C. The DMF solution was then poured into the PVP solution, and the mixture was stirred at 30 °C for 4 h to obtain a homogeneous reddish-brown solution. This solution was then filled into a 10 ml plastic syringe, with the distance between the metal tip and the collecting plate set to 20 cm. An 11.5 kV voltage was applied, and the flow rate was maintained at 5.5 μl / min. The collected nanotubes were then annealed at 700 °C for 2 h to obtain the final EuFeO3 nanotubes. Four platinum wires were pre-attached to both ends of an alumina ceramic tube, and a nickel-chromium alloy coil was inserted into the alumina ceramic tube as a heating wire. The two ends of the platinum wires and the heating wire were sequentially welded to the electrode posts to form a sensor. The obtained EuFeO3 nanotubes were ground into powder in a mortar to obtain EuFO3 sample powder. A small amount of powder was placed in a clean container and an appropriate amount of deionized water was added to form a slurry. The slurry was evenly coated onto the surface of the sensor with a small brush. The coated sensor was then dried at room temperature. When the coating surface was dry, the sensor was placed in an aging chamber and aged at 210°C for 44 hours to achieve optimal stability.
[0023] Study on the gas-sensitive properties of the sample in Example 8 above for ethylene Figure 5 Figures (a) and (c) show the sensing characteristics of ethylene gas released by bananas and melons from day 0 to day 14. On the first day, the activation energy of ethylene is insufficient, making it difficult to adsorb onto the sample surface, resulting in a low response. As time progresses and the ethylene content released by bananas and melons increases, the ethylene molecules gain more energy, and their gas sensitivity increases accordingly. Similarly, Figure (e) shows the test results for cherries from day 0 to day 12. Figures (b), (d), and (f) are the corresponding response diagrams. As the concentration of ethylene released by the fruit increases, the sensor resistance first increases and then decreases. After ethylene desorption was complete, all samples returned to their initial state, indicating that the detection of ethylene was reversible for all samples. The response value increased with increasing ethylene gas concentration, which means that the sensor made from EuFeO3 sample has a high detection limit. The figure also shows that it maintains a better linear relationship in the low concentration range, and the sensor has good repeatability and stability for low concentration testing, indicating that the sensor can be used to detect low concentrations of ethylene gas.
Claims
1. A method for preparing a europium ferrite nanosensor, characterized in that, The method describes the preparation of hollow nanotube materials with surface oxygen vacancy defects and the construction of sensors through electrospinning combined with a calcination process within a specific temperature range, including the following steps: Step 1: Dissolve Eu(NO3)3·6H2O and Fe(NO3)3·9H2O in N,N-dimethylformamide (DMF) and stir to form a metal salt solution; simultaneously, dissolve polyvinylpyrrolidone (PVP) in anhydrous ethanol and stir to form a polymer solution; mix the metal salt solution and the polymer solution, and stir at a constant temperature of 25℃~35℃ for 3.5h~4.5h, using the coordination effect of PVP molecular chains and metal ions to regulate the solution viscosity, to obtain the spinning precursor solution; wherein, the mass ratio of Eu(NO3)3·6H2O, Fe(NO3)3·9H2O to PVP is controlled between (0.28-0.45): (0.25-0.40): (0.25-0.35); Step 2: Place the spinning precursor solution in an electrospinning device and spin under the conditions of applying a voltage of 11.5kV, receiving distance of 15cm to 25cm, and feed flow rate of 5.0 to 6.0μl / min to obtain Eu / Fe / PVP composite precursor fiber; Step 3: The composite precursor fiber is calcined at a temperature range of 550℃ to 700℃ for 1.5h to 2.0h. By controlling the difference between the thermal decomposition rate and the grain growth rate of PVP, a hollow EuFeO3 nanotube structure is induced to form inside the fiber. At the same time, by limiting the maximum calcination temperature, 32.0% to 36.0% of vacant oxygen (O2) is retained in situ in the nanotube surface lattice. v )defect; Step 4: Mix the prepared EuFeO3 nanotubes with deionized water, grind and disperse them to form a suspension homogenate, and coat it on the surface of an alumina ceramic tube prefabricated with heating and testing electrodes; after drying, age it at 180℃~220℃ for 36h~48h to obtain the gas sensor.
2. The method for preparing a europium ferrite nanosensor according to claim 1, characterized in that: The EuFeO3 hollow nanotubes prepared in step three have an outer diameter distribution range of 200 nm to 400 nm, and the tube walls are composed of nanoparticles and exhibit a porous and rough morphology.
3. The application of the europium ferrite nanosensor according to claim 1, characterized in that: Utilizing the high concentration of vacant oxygen (O) on the surface of the nanotubes v It acts as an active site for adsorbing ethylene molecules.