A hybrid potentiometric isoprene sensor based on Gd₂Zr₂O₇ solid electrolyte, its preparation method and its application

Abstract

A kind of hybrid potential type isoprene sensor based on Gd2Zr2O7 solid electrolyte, preparation method and application thereof belong to gas sensor technical field.It is composed of Al2O3 ceramic plate with Pt heating electrode, Gd2Zr2O7 solid electrolyte substrate, CdSb2O6 sensitive electrode and Pt reference electrode, CdSb2O6 sensitive electrode and Pt reference electrode are respectively prepared on the two ends of the upper surface of Gd2Zr2O7 solid electrolyte substrate, the lower surface of Gd2Zr2O7 solid electrolyte substrate is bonded together with the surface of Al2O3 ceramic plate with Pt heating electrode through inorganic adhesive.The application constructs Gd2Zr2O7 solid electrolyte base isoprene sensor with CdSb2O6 sensitive electrode material, can realize high sensitivity, high stability detection to 0.05-100ppm isoprene, and can be applied in isoprene dynamic monitoring in human movement process.

Description

Technical Field

[0001] This invention belongs to the field of gas sensor technology, specifically relating to a hybrid potential type isoprene sensor based on Gd2Zr2O7 solid electrolyte, its preparation method, and its application in dynamic monitoring of isoprene during human movement. Background Technology

[0002] Detecting specific components in human exhaled breath using gas analysis technology has become an emerging non-invasive diagnostic technique. Gas sensors, due to their miniaturization and portability, have become the best choice for real-time and large-scale monitoring. The biological source of isoprene in the human body has been revealed for the first time in the last two years. The isoprene in exhaled breath mainly originates from muscle metabolism. Therefore, monitoring isoprene in human exhaled breath can dynamically reflect the physiological state of muscle metabolism during exercise. This is of great importance for guiding athletes' training and is expected to provide technical means for further research on the relationship between exercise, skeletal muscle, and organ metabolism.

[0003] Many isoprene sensors based on oxide semiconductors have been developed. However, the sensitivity of these gas sensors is greatly affected by humidity. Since exhaled gas has a complex composition and high humidity, solid electrolyte gas sensors with good moisture resistance and stability have greater application potential for exhaled gas detection.

[0004] Solid electrolyte sensors typically consist of a solid electrolyte, a sensitive electrode, and a reference electrode. Their sensing signal is primarily determined by the electrochemical reaction at the electrode / electrolyte / gas three-phase interface (TPB). The sensing process and mechanism can be explained using the hybrid potential theory. For a typical sensing process, gas molecules first undergo a heterogeneous catalytic reaction within the electrode layer during diffusion (reaction (1)). After diffusing to the TPB, they undergo electrochemical reactions (2) and (3) with O2. When the reaction rates of (2) and (3) are equal, the reaction reaches dynamic equilibrium, forming a hybrid potential on the electrode. Therefore, the sensor's sensitivity is also influenced by the heterogeneous catalytic reaction, and is closely related to the electrochemical activity, catalytic activity, microstructure of the sensitive electrode material, and the composition and reactive sites of the three-phase interface.

[0005] The reaction formula is:

[0006] C5H8+9 / 2O2=5CO+4H2O (1)

[0007] O2+4e - =2O 2- (2)

[0008] C5H8+9O 2-= 5CO + 4H2O + 18e - (3)

[0009] Although hybrid potential sensors have shown great application potential in breath detection, research on hybrid potential sensors for isoprene detection has not yet been reported. To achieve the detection of more types of gases, the expansion of novel solid electrolyte systems and the development of high-performance sensitive electrode materials have been the focus of researchers in this field. Summary of the Invention

[0010] This invention provides a hybrid potential-type isoprene sensor based on Gd2Zr2O7 solid electrolyte, its preparation method, and its application in dynamic monitoring of isoprene during human movement. The prepared sensor has high sensitivity, low detection limit, good selectivity, and stability for isoprene.

[0011] The hybrid potential-type isoprene sensor based on Gd₂Zr₂O₇ solid electrolyte described in this invention is constructed using Gd₂Zr₂O₇ as the solid electrolyte, Pt as the reference electrode, and CdSb₂O₆ as the sensitive electrode. Its structure is as follows: Figure 1 As shown. The sensor of this invention has a planar layered structure, consisting from bottom to top of an Al2O3 ceramic plate with a Pt heating electrode, a Gd2Zr2O7 solid electrolyte substrate, a CdSb2O6 sensitive electrode, and a Pt reference electrode. The CdSb2O6 sensitive electrode and the Pt reference electrode are respectively fabricated at both ends of the upper surface of the Gd2Zr2O7 solid electrolyte substrate. The lower surface of the Gd2Zr2O7 solid electrolyte substrate is bonded to the surface of the Al2O3 ceramic plate with the Pt heating electrode using an inorganic adhesive. The sensor of this invention exhibits good sensitivity to isoprene, achieving high sensitivity and high stability detection of isoprene from 0.05 to 100 ppm.

[0012] The preparation method of a hybrid potential-type isoprene sensor based on Gd2Zr2O7 solid electrolyte according to the present invention comprises the following steps:

[0013] A. Preparation of electrolyte substrate

[0014] Gd₂Zr₂O₇ solid electrolyte substrate was prepared by hydrothermal method: 5 mmol of Gd(NO₃)₃·6H₂O, 5 mmol of ZrOCl₂·8H₂O and 25 mmol of urea (precipitant) were dissolved sequentially in 30-50 mL of deionized water. After stirring for 20-40 min, the resulting solution was transferred to a 100 mL polytetrafluoroethylene reactor and reacted at 170-190 °C for 22-26 h. The white precipitate was collected and washed alternately with deionized water and ethanol, centrifuged, and dried. The resulting powder was pre-sintered at 500-700 °C for 3-5 h to remove moisture and organic impurities, and then pressed into discs under a pressure of 280-300 MPa. Finally, it was sintered at 1500-1600 °C for 3-5 h and cut to obtain the Gd₂Zr₂O₇ solid electrolyte substrate.

[0015] B. Preparation of CdSb2O6 Sensitive Electrode Material

[0016] CdSb2O6 sensitive electrode material was synthesized by hydrothermal method: 5 mmol of Sb2O5, 5 mmol of Cd(NO3)2·4H2O and 0.1 g of hexadecyltrimethylammonium bromide (CTAB) were dissolved sequentially in 60-80 mL of ethanol and stirred for 20-40 min. Ammonia water was added dropwise to the resulting solution until the pH of the solution was 6-8. The solution was then transferred to a 100 mL polytetrafluoroethylene reactor and reacted at 150-170 °C for 22-26 h. The precipitate obtained from the reaction was collected, washed alternately with deionized water and ethanol, centrifuged, and dried. The resulting powder was sintered at 800-1000 °C for 3-5 h to obtain CdSb2O6 sensitive electrode material.

[0017] C. Sensor fabrication

[0018] Strip-shaped reference and sensing electrodes were fabricated on a Gd₂Zr₂O₇ solid electrolyte substrate. Then, an Al₂O₃ ceramic plate with a Pt heating electrode was adhered to the lower surface of the electrolyte substrate using an inorganic binder to provide the required operating temperature for the sensor. Specific steps included:

[0019] (1) Fabrication of Pt reference electrode: A 5-10 μm thick Pt paste is brushed onto one side of the upper surface of the Gd2Zr2O7 solid electrolyte substrate obtained in step A as a reference electrode. At the same time, two Pt wires are folded in half. One Pt wire is glued to the middle position of the reference electrode with Pt paste as a reference electrode lead, and the other Pt wire is glued to the other end of the upper surface of the Gd2Zr2O7 solid electrolyte substrate as a sensitive electrode lead. The Gd2Zr2O7 solid electrolyte substrate is baked at 90-120℃ for 20-40 min, and then sintered at 900-1100℃ for 20-40 min to remove the organic solvent in the Pt paste and solidify the Pt paste to ensure good contact between the reference electrode, the lead and the electrolyte substrate. Finally, it is cooled to room temperature.

[0020] (2) Fabrication of CdSb2O6 sensitive electrode: The CdSb2O6 sensitive electrode material obtained in step B is mixed with deionized water to prepare a viscous CdSb2O6 slurry; the CdSb2O6 slurry is dipped with a brush to prepare a sensitive electrode with a thickness of 80-100 μm on one side of the sensitive electrode lead of the Gd2Zr2O7 solid electrolyte substrate in step (1); then the electrolyte substrate is placed in a muffle furnace and heated to 800-1000℃ at a heating rate of 1.5-3.0℃ / min, and sintered for 2-3 hours to ensure close contact between the sensitive electrode and the electrolyte;

[0021] (3) Bonding Al2O3 ceramic plate with Pt heating electrode: First, mix 2-4 mL of Na2SiO3·9H2O with 0.7-1.0 g of Al2O3 powder and stir evenly to prepare an inorganic binder; prepare an “M”-shaped Pt heating electrode on the Al2O3 ceramic plate by screen printing; use the inorganic binder to bond the Al2O3 ceramic plate with Pt heating electrode to the lower surface of the solid electrolyte substrate and make the Pt heating electrode contact the lower surface of the solid electrolyte substrate.

[0022] (4) The device obtained in step (3) is welded and packaged to obtain the hybrid potential type isoprene sensor based on Gd2Zr2O7 solid electrolyte as described in this invention.

[0023] Advantages of this invention:

[0024] (1) An isoprene sensor was constructed using Gd2Zr2O7 solid electrolyte. This type of solid electrolyte is advantageous for obtaining high conductivity at lower temperatures, thus expanding the types of solid electrolyte isoprene sensors.

[0025] (2) A CdSb2O6 sensitive electrode material was prepared, which has high electrochemical catalytic activity for isoprene;

[0026] (3) For the first time, a Gd2Zr2O7 solid electrolyte-based isoprene sensor was constructed using CdSb2O6 sensitive electrode material, realizing high sensitivity and high stability detection of isoprene gas by a solid electrolyte gas sensor. Attached Figure Description

[0027] Figure 1 : A schematic diagram of the structure of the hybrid potential-type isoprene sensor based on Gd2Zr2O7 solid electrolyte described in this invention;

[0028] The sensor has a planar layered structure, consisting of an Al2O3 ceramic plate 7 with a Pt heating electrode 6, a Gd2Zr2O7 solid electrolyte substrate 1, a Pt reference electrode 2, and a CdSb2O6 sensitive electrode 3 from bottom to top. The Pt reference electrode 2 and the CdSb2O6 sensitive electrode 3 are respectively fabricated at both ends of the upper surface of the Gd2Zr2O7 solid electrolyte substrate 1. The lower surface of the Gd2Zr2O7 solid electrolyte substrate 1 is bonded to the surface of the Al2O3 ceramic plate 7 with the Pt heating electrode 6 by an inorganic adhesive 5. Pt leads 4 are fabricated on the Pt reference electrode 2 and the CdSb2O6 sensitive electrode 3.

[0029] Figure 2 XRD and SEM images of the CdSb2O6 sensitive material prepared in this invention;

[0030] like Figure 2 (a) shows the XRD pattern of the prepared sensitive material. The diffraction peaks are consistent with the standard card JCPDS#44-219 of CdSb2O6, indicating that the sensitive electrode material prepared in this invention is CdSb2O6. Figure 2 (b) is a surface SEM image of the sensitive electrode. It can be seen that the CdSb2O6 sensitive material is composed of irregular micro and nano particles, and a large number of pore structures are visible on the surface, which is conducive to the migration and diffusion of gas molecules in the sensitive electrode layer. Figure 3 The inset in (b) is a cross-sectional SEM image of the sensitive electrode, which shows that the thickness of the sensitive electrode layer is approximately 90.3 μm.

[0031] Figure 3 The continuous response recovery curve (a) of the Gd2Zr2O7 solid electrolyte-based hybrid potentiometric isoprene sensor with CdSb2O6 as the sensitive electrode prepared in this invention, at 530℃ and 70% RH, the response recovery characteristic curve (b) in 20ppm isoprene, and the relationship curves between the response value and the isoprene concentration (c, d) are shown.

[0032] like Figure 3 (a) shows the continuous response recovery curves of the sensor based on Gd2Zr2O7 solid electrolyte with CdSb2O6 as the sensitive electrode to isoprene from 0.05 to 100 ppm. The main plot is for the concentration range of 0.5 to 100 ppm, and the inset is for the concentration range of 0.05 to 0.2 ppm. It can be seen that the sensor has good response recovery characteristics to isoprene from 0.05 to 100 ppm. Figure 3(b) shows the response recovery characteristic curve of the sensor in 20 ppm isoprene. The response recovery times of the sensor to 20 ppm isoprene are 30 s and 136 s, respectively. The response time is defined as the time required for the sensor to reach 90% of the potential value change from contact with the gas to be measured, and the recovery time is the time required for the sensor to recover 90% of the potential value from being removed from the gas to be measured and re-exposed to the air. Figure 3 (c,d) represents the relationship curve between the sensor's response value (defined as the difference between the potential values ​​between the sensitive electrode and the reference electrode in different concentrations of isoprene gas and in air, measured by a Fluke 8846A digital multimeter connected between the two electrodes of the sensor) and the isoprene concentration. The sensor's response values ​​to different concentrations of isoprene are listed in Table 1. It can be seen that the response value and concentration exhibit linear and logarithmic linear relationships in the ranges of 0.05–1 ppm and 1–100 ppm, respectively. The slope of the fitted line is defined as the sensor's sensitivity. The sensor's sensitivities to 0.05–1 ppm and 1–100 ppm isoprene are -21.2 mV / ppm and -65.8 mV / decade, respectively.

[0033] Figure 4 A bar graph showing the response values ​​of a Gd2Zr2O7 solid electrolyte-based hybrid potentiometric isoprene sensor with CdSb2O6 as the sensitive electrode, using different gases.

[0034] like Figure 4 The figure shows a bar graph illustrating the response values ​​of the Gd2Zr2O7 solid electrolyte-based hybrid potentiometric isoprene sensor prepared in this invention, using CdSb2O6 as the sensitive electrode, to different concentrations of interfering gases such as acetone, formaldehyde, benzene, CO2, CO, and H2. The sensor's response values ​​to 0.5 ppm of isoprene, acetone, formaldehyde, and benzene are -13.0 mV, -4.2 mV, -1.9 mV, and -1.9 mV, respectively. The sensor's response values ​​for isoprene (-0.4 mV), acetone (-78.8 mV), formaldehyde (-41.5 mV), and benzene (-11.3 mV) at concentrations of 50 ppm are -0.4 mV, respectively. This shows that the sensor's response to isoprene at 0.5 ppm and 50 ppm is much higher than that to other gases. Furthermore, the response values ​​for CO2, CO, and H2 at concentrations as high as 1000 ppm are only -1.4 mV, -5.5 mV, and -28.8 mV, respectively, indicating that the sensor has excellent selectivity.

[0035] Figure 5The response curves of a Gd2Zr2O7 solid electrolyte-based hybrid potentiometric isoprene sensor with CdSb2O6 as the sensitive electrode to 2 ppm isoprene under different relative humidity conditions (a) and the long-term stability curve of the sensor during a continuous 60-day high-temperature aging process (b).

[0036] like Figure 5 As shown in (a), the response curves of the Gd2Zr2O7 solid electrolyte-based hybrid potentiometric isoprene sensor with CdSb2O6 as the sensitive electrode prepared in this invention to 2 ppm isoprene under different relative humidity conditions are shown. It can be seen that the response value of the sensor is relatively high under low humidity conditions, while it remains relatively stable in the higher humidity range of 60-90% RH. This is closer to the humidity range of exhaled breath. The good stability in this high humidity range ensures the reliability of exhaled breath detection. Figure 5 (b) shows the response curve of the sensor to 5 ppm isoprene during a continuous 60-day high-temperature aging process. The maximum fluctuation during this period was only -12.7%, which also showed good long-term stability.

[0037] Figure 6 The response of a Gd2Zr2O7 solid electrolyte-based hybrid potentiometric isoprene sensor with CdSb2O6 as the sensitive electrode to the exhaled air of volunteers at different stages of exercise (a) and the calculated concentration change of isoprene in exhaled air (b).

[0038] like Figure 6 The image shows the application of the Gd2Zr2O7 solid electrolyte-based hybrid potentiometric isoprene sensor with CdSb2O6 as the sensitive electrode, prepared according to this invention, in monitoring human movement. The sensor was used to test the exhaled breath of athletes in a relaxed state before exercise, at 2 min, 5 min, 10 min, 15 min, and 20 min after exercise, and at a 20 min rest period after exercise. Figure 6 (a) shows the change in the sensor response value. Based on the sensor response value and... Figure 3 The sensitivity curves (c,d) can be used to calculate the isoprene concentration in exhalation at different stages, such as... Figure 6 As shown in (b), it can be seen that by testing the exhaled air at different stages of exercise using the sensor, the trend of isoprene concentration change was obtained. In the calm state before exercise, the isoprene concentration in exhaled air was only 30 ppb. After the start of exercise, the isoprene content increased sharply to about 700 ppb, and then gradually decreased to the initial content level. The sensor successfully realized the dynamic monitoring of isoprene content in exhaled air during exercise. Detailed Implementation

[0039] Example 1:

[0040] The CdSb₂O₆ sensitive electrode material was prepared, a planar sensor was fabricated on a Gd₂Zr₂O₇ solid electrolyte substrate, and its gas-sensing performance was tested. The specific process is as follows:

[0041] 1. Preparation of Gd₂Zr₂O₇ solid electrolyte substrate: 5 mmol of Gd(NO₃)₃·6H₂O, 5 mmol of ZrOCl₂·8H₂O, and 25 mmol of urea (as a precipitant) were dissolved in 40 mL of deionized water and stirred for 30 min. After the solution was completely mixed, it was transferred to a 100 mL polytetrafluoroethylene reactor and placed in an oven. The reactor was reacted at 180 °C for 24 h. The precipitate obtained from the reaction was collected, washed alternately with deionized water and ethanol, centrifuged, and dried. The resulting powder was pre-sintered at 600 °C for 4 h to ensure thorough drying and remove impurities. Then, it was formed into a disc with a certain diameter and thickness under a pressure of 290 MPa. The disc was then sintered at 1550 °C for 4 h to obtain an electrolyte plate. Finally, the obtained electrolyte plate was cut into thin-film electrolyte substrates with certain geometric dimensions (2 mm long × 2 mm wide × 0.3 mm thick) for sensor fabrication.

[0042] 2. Fabrication of Pt reference electrode: A 0.5mm × 2mm, 8μm thick Pt reference electrode was fabricated on one side of the upper surface of the Gd2Zr2O7 solid electrolyte substrate obtained in step 1 using Pt paste. At the same time, two Pt wires were folded in half. One wire was attached to the middle of the reference electrode with Pt paste as a reference electrode lead, and the other wire was attached to the other end of the upper surface of the electrolyte substrate as a sensitive electrode lead. The electrolyte substrate was then baked at 110℃ for 30min, and then sintered at 1000℃ for 30min to remove the organic solvent in the Pt paste and to solidify the Pt paste to ensure good contact between the reference electrode, the lead, and the electrolyte substrate. Finally, the substrate was cooled to room temperature.

[0043] 3. Fabrication of CdSb₂O₆ sensitive electrode: 5 mmol of Sb₂O₅, 5 mmol of Cd(NO₃)₂·4H₂O, and 0.1 g of hexadecyltrimethylammonium bromide (CTAB) were dissolved sequentially in 70 mL of ethanol and stirred for 20 min. Ammonia water was added dropwise to the solution until the pH reached 7. The solution was then transferred to a 100 mL polytetrafluoroethylene reactor and reacted at 160 °C for 24 h. The precipitate obtained from the reaction was collected, washed alternately with deionized water and ethanol, centrifuged, and dried. The resulting powder was sintered at 900 °C for 4 h to obtain the CdSb₂O₆ sensitive electrode material.

[0044] Take 20 mg of powdered CdSb2O6 sensitive electrode material and mix it with 2 mL of deionized water to prepare a slurry with a certain viscosity. Use a brush to dip the slurry and coat a 0.5 mm × 2 mm thick sensitive electrode on one side of the sensitive electrode lead prepared in step 2, so that it completely covers the junction between the sensitive electrode lead and the electrolyte substrate.

[0045] The prepared electrolyte substrate with reference and sensitive electrodes was placed in a muffle furnace and heated to 900°C at a heating rate of 2.0°C / min and held for 2 hours before being cooled to room temperature.

[0046] 4. Bonding the ceramic plate with heating electrodes: First, an inorganic adhesive is prepared using Al2O3 and Na2SiO3·9H2O (water glass) in a mass ratio of 5:1. The lower surface of the electrolyte substrate (the side without electrodes) is then bonded to an Al2O3 ceramic plate of the same size (2mm x 2mm, 0.2mm thick) with “M”-shaped Pt heating electrodes using the inorganic adhesive.

[0047] 5. Device soldering and packaging. The device is soldered onto a hexagonal socket, covered with a protective cover, and the isoprene sensor based on Gd2Zr2O7 solid electrolyte with CdSb2O6 as the sensitive electrode is completed.

[0048] 6. Gas-sensing test of the fabricated device: An ammeter was connected to both ends of an Al2O3 ceramic plate with a Pt heating electrode to control the sensor's operating temperature by controlling the current. The fabricated sensor was connected to a Fluke 8846A digital multimeter, with the sensitive electrode connected to the positive terminal of the multimeter and the reference electrode connected to the negative terminal. The sensor was placed in air, 50 ppb isoprene, 0.1 ppm isoprene, 0.2 ppm isoprene, 0.5 ppm isoprene, 1 ppm isoprene, 2 ppm isoprene, 5 ppm isoprene, 10 ppm isoprene, 20 ppm isoprene, 50 ppm isoprene, and 100 ppm isoprene gases to collect potential signals. The difference between the potential of the device in different concentrations of isoprene and the potential in air was taken as the sensor's response value. The experimental results are shown in Table 1.

[0049] Table 1: Response data of the isoprene sensor prepared in this invention to different concentrations of isoprene at 530℃

[0050]

[0051] Table 1 shows the response values ​​of the isoprene sensor prepared in this invention to different concentrations of isoprene at 530℃. Each concentration was tested three times. It can be seen that the sensor's response values ​​to each concentration of isoprene gas are very close in the three tests, indicating that the sensor has stable and reliable sensitivity. The sensor can detect isoprene as low as 50 ppb with a response value of -2.4 mV, exhibiting an extremely low detection limit.

Claims

1. A method for preparing a hybrid potentiometric isoprene sensor based on Gd₂Zr₂O₇ solid electrolyte, comprising the following steps: A. Preparation of electrolyte substrate Gd₂Zr₂O₇ solid electrolyte substrate was prepared by hydrothermal method: 5 mmol of Gd(NO₃)₃·6H₂O, 5 mmol of ZrOCl₂·8H₂O and 25 mmol of urea were dissolved sequentially in 30–50 mL of deionized water. After stirring for 20–40 min, the resulting solution was transferred to a 100 mL polytetrafluoroethylene reactor and reacted at 170–190 °C for 22–26 h. The white precipitate was collected and washed alternately with deionized water and ethanol, centrifuged, and dried. The resulting powder was pre-sintered at 500–700 °C for 3–5 h to remove moisture and organic impurities, and then pressed into discs under a pressure of 280–300 MPa. Finally, it was sintered at 1500–1600 °C for 3–5 h and cut to obtain the Gd₂Zr₂O₇ solid electrolyte substrate. B. Preparation of CdSb2O6 Sensitive Electrode Material CdSb2O6 sensitive electrode material was synthesized by hydrothermal method: 5 mmol of Sb2O5, 5 mmol of Cd(NO3)2·4H2O and 0.1 g of hexadecyltrimethylammonium bromide (CTAB) were dissolved sequentially in 60-80 mL of ethanol and stirred for 20-40 min. Ammonia water was added dropwise to the resulting solution until the pH of the solution was 6-8. The solution was then transferred to a 100 mL polytetrafluoroethylene reactor and reacted at 150-170 °C for 22-26 h. The precipitate obtained from the reaction was collected, washed alternately with deionized water and ethanol, centrifuged, and dried. The resulting powder was sintered at 800-1000 °C for 3-5 h to obtain CdSb2O6 sensitive electrode material. C. Sensor fabrication (1) Fabrication of Pt reference electrode: A 5-10 μm thick Pt paste is brushed onto one side of the upper surface of the Gd2Zr2O7 solid electrolyte substrate obtained in step A as a reference electrode. At the same time, two Pt wires are folded in half. One Pt wire is glued to the middle position of the reference electrode with Pt paste as a reference electrode lead, and the other Pt wire is glued to the other end of the upper surface of the Gd2Zr2O7 solid electrolyte substrate as a sensitive electrode lead. The Gd2Zr2O7 solid electrolyte substrate is baked at 90-120℃ for 20-40 min, then sintered at 900-1100℃ for 20-40 min, and finally cooled to room temperature. (2) Fabrication of CdSb2O6 sensitive electrode: The CdSb2O6 sensitive electrode material obtained in step B is mixed with deionized water to prepare a viscous CdSb2O6 slurry; the CdSb2O6 slurry is dipped with a brush to prepare an 80-100 μm thick sensitive electrode on one side of the sensitive electrode lead of the Gd2Zr2O7 solid electrolyte substrate in step (1); then the electrolyte substrate is placed in a muffle furnace and sintered at 800-1000℃ for 2-3 h. (3) Bonding Al2O3 ceramic plate with Pt heating electrode: First, mix 2-4 mL of Na2SiO3·9H2O with 0.7-1.0 g of Al2O3 powder and stir evenly to prepare an inorganic binder; prepare an "M"-shaped Pt heating electrode by screen printing on Al2O3 ceramic plate; use inorganic binder to bond Al2O3 ceramic plate with Pt heating electrode to the lower surface of solid electrolyte substrate and make Pt heating electrode contact with the lower surface of solid electrolyte substrate. (4) The device obtained in step (3) is welded and packaged to obtain the hybrid potential type isoprene sensor based on Gd2Zr2O7 solid electrolyte.

2. The hybrid potential type isoprene sensor based on Gd2Zr207 solid electrolyte according to claim 1, characterized in that: In step (2), the temperature is increased to 800-1000℃ at a heating rate of 1.5-3.0℃ / min.

3. A hybrid potentiometric isoprene sensor based on Gd₂Zr₂O₇ solid electrolyte, characterized in that: It is prepared by the method described in claim 1.

4. The application of the hybrid potential type isoprene sensor based on Gd2Zr2O7 solid electrolyte as described in claim 3 in the dynamic monitoring of isoprene during human movement.

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