A hydrogen gas sensor based on ZnO / In2O3 heterostructure and its preparation method

Abstract

A hydrogen sensor based on ZnO / In2O3 heterostructure described in this application includes a substrate, a dielectric layer, and a gas sensing layer. Among them, the dielectric layer is disposed on the substrate, the gas sensing layer is disposed on the dielectric layer, the dielectric layer contains a high work function metal, and the gas sensing layer includes a ZnO / In2O3 heterostructure nanowire film and an electrode. The device prepared by the preparation method described in this application can obtain a lower detection limit, providing a practical new method for ppb-level hydrogen sensing.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen sensing, and particularly relates to a hydrogen sensor based on a ZnO / In2O3 heterostructure and a preparation method thereof. Background Art

[0002] Energy plays a crucial role in promoting the development of human society. With the increasing severity of environmental pollution and the consumption of non-renewable resources, the requirement for green and low-carbon development has become a trend, and it is becoming more urgent to find clean energy to replace traditional fossil fuels. Hydrogen (H2) has always been regarded as one of the cleanest renewable energies, and its high energy density, high combustion efficiency, convenient preparation, and pollution-free combustion products have received extensive attention. However, due to the small volume of hydrogen molecules, which are extremely easy to leak, its wide combustion range (~4%-75%) and explosion range (~15%-59%) pose the biggest safety hazard in the current use process. Moreover, H2 is extremely easy to combine with human hemoglobin, and as the accumulation of H2 in the air increases, it may cause hypoxia and asphyxiation. Due to its colorless and odorless nature, it is difficult to detect or perceive through the human sensory organs, so it still poses a challenge. Traditional detection methods are usually relatively complex, and the detection instruments are also relatively expensive. It is urgent to study new detection means. In order to detect H2 leakage during storage and transportation in a timely manner and avoid large-scale social hazards, it is urgent to develop various H2 detection devices.

[0003] Among the gas sensor materials so far, resistive gas sensors are the most favored by researchers. Due to the extraordinary physical and chemical properties of metal oxide semiconductor (MOS) nanomaterials in terms of optical, electrical, and magnetic properties, the gas concentration can be well detected in real time according to the resistance change of MOS in different atmospheres. However, these sensors generally have the disadvantages of long response time and high detection limit, which limit their application at extremely low hydrogen concentrations. Therefore, the trace detection of hydrogen leakage is still a technical problem existing in hydrogen storage and urgently needs to be solved. Summary of the Invention

[0004] The invention technical team studied the above-mentioned intractable technical problems and found that by simultaneously using two n-type semiconductor materials, ZnO and In2O3, and through reasonable design, they can play a good synergistic effect, which can well improve the sensing performance of the sensor. Both ZnO and In2O3 semiconductors have high electron mobility and excellent optoelectronic properties, and are both direct wide-bandgap materials. The electronic structures of their nanowires are easily affected by the external gas atmosphere. After repeated research and experiments, a hydrogen sensor with a ZnO / In2O3 heterostructure was finally obtained, which can quickly detect the hydrogen concentration for the problem of extremely low hydrogen concentration leakage.

[0005] Therefore, on the one hand, the present invention provides a hydrogen sensor based on a ZnO / In2O3 heterostructure. The hydrogen sensor includes a substrate, a dielectric layer, and a gas sensing layer. Among them, the dielectric layer is disposed on the substrate, the gas sensing layer is disposed on the dielectric layer, the dielectric layer contains a high work function metal, and the gas sensing layer includes a ZnO / In2O3 heterostructure nanowire film and an electrode.

[0006] Furthermore, in the hydrogen sensor of the present invention, the molar ratio n(Zn):n(In) in the ZnO / In2O3 heterostructure nanowire film is 95:5 to 85:15. Both ZnO and semiconductors have high electron mobility and excellent optoelectronic properties, and are both direct wide-bandgap materials. The electronic structures of the two nanowires are easily affected by the external gas atmosphere. And when n(Zn):n(In) is between 95:5 and 85:15, due to the different work functions, a built-in electric field is formed at the contact between ZnO and In2O3, and a contact potential barrier is formed at the contact interface, which can appropriately increase the resistance of the nanowire film. However, when the concentration of In2O3 is too high, the ability of ZnO to reduce the resistance provided by the metallization behavior in the hydrogen atmosphere will be reduced. Considering both, the optimal content ratio is between 95:5 and 85:15.

[0007] Furthermore, in the hydrogen sensor of the present invention, the thickness of the dielectric layer is 200 - 5000 nm, preferably 200 - 2000 nm, and more preferably 500 - 1000 nm. When the thickness is less than 200 nm, it is not easy to form a thin film for the dielectric layer. On the contrary, when the thickness is greater than 5000 nm, first, the heterojunction thin film on the surface layer will adsorb oxygen and form a depletion layer, resulting in a high resistance state. The heterojunction thin film at the bottom layer has a low probability of contacting oxygen in the air and is in a low resistance state. The current tends to flow through the low resistance system more, which is not conducive to gas sensing. Secondly, the thick dielectric layer will not only agglomerate into large particles but also easily detach from the substrate.

[0008] Furthermore, in the hydrogen sensor of the present invention, the substrate layer is selected as a quartz wafer, and the high work function metal is selected from one of Au, Pt, and Pd, preferably Au. For the hydrogen sensor core provided by the present invention, a ZnO / In2O3 nanowire film is synthesized on the Au thin film.

[0009] Furthermore, in the hydrogen sensor of the present invention, the electrodes in the gas sensing layer are disposed on both sides of the ZnO / In2O3 heterostructure nanowire film. It is a necessary condition that the high work function metals in the dielectric layer are arranged in a spaced strip shape and the two pieces of metal are not electrically connected to form electrodes.

[0010] On the other hand, the present invention also provides a preparation method for the above hydrogen sensor based on a ZnO / In2O3 heterostructure, including the following steps:

[0011] (1) Deposit the high work function metal on the substrate by magnetron sputtering, electron beam deposition or thermal evaporation to form the dielectric layer thin film;

[0012] (2) Add Zn(CH3COO)2·2H2O and In(NO3)3 to DMF and continuously stir for 2.5 h to 3.8 h to obtain solution a;

[0013] (3) Slowly add PVP (M≈1300000) to the solution a and continuously stir until completely dissolved to obtain solution b;

[0014] (4) Draw the solution b into a syringe and electrospin on the dielectric thin film to synthesize the ZnO / In2O3 nanowire film; after the electrospinning, dry at 56 - 66 °C for 20 - 28 h to obtain the precursor of the sensor core; in this step, when drawing the mixed solution into the syringe during the electrospinning process, avoid the presence of air bubbles in the syringe.

[0015] (5) Anneal the precursor at an annealing temperature of 600 °C ± 10 °C, an annealing time of 1.8 - 2.5 h, and a heating rate of 5 °C / min ± 0.5 to obtain the sensor core;

[0016] (6) Make electrodes for the sensor core with carbon paste and lead out wires, and heat at a constant temperature of 65 - 72 °C to dry the carbon paste to obtain the hydrogen sensor.

[0017] Further, in the method for preparing the hydrogen sensor of the present invention, the percentage content of salt in the solution b is C bsalt , C bsalt = 8.0 - 9.2%; the percentage content of PVP in the solution b is C bpvp , C bpvp = 8.5 - 9.5%.

[0018] Further, in the method for preparing the hydrogen sensor of the present invention, the addition rate of PVP (M≈1300000) in the step (3) cannot exceed 0.5 g / min. Slowly adding PVP is beneficial to the full dissolution of PVP in the DMF solution. If the rate exceeds 0.5 g / min, PVP is prone to agglomerate into large particles, the dissolution time is prolonged and it is difficult to dissolve.

[0019] Further, in the electrospinning process of the step (4) in the method for preparing the hydrogen sensor of the present invention, the humidity is below 30% and the temperature is below 30 °C; the electrospinning parameters are set as the positive pressure is 20 KV ± 1.5 KV, the negative pressure is 2 KV ± 0.05 KV, and the distance between the needle and the receiving plate is 20 cm ± 2.6 cm.

[0020] Further, in the method for preparing the hydrogen sensor of the present invention, a magnetic stirrer is used in the stirring processes of steps (2) and (3), and the stirring processes are carried out in a sealed manner to prevent the volatilization of reagents.

[0021] Some other oxide or oxide heterojunction (n-n type heterojunction) nanowire films can be prepared by using the above method. Furthermore, a hydrogen sensor core capable of rapidly detecting the hydrogen concentration can be prepared.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) The two semiconductor materials ZnO and In2O3 used in the present invention are both n-type semiconductors, both having high electron mobility and excellent optoelectronic properties. The band gaps of ZnO and In2O3 are 3.37 eV and 3.6 eV respectively, and both are direct wide-bandgap materials. In particular, the electronic structures of ZnO and In2O3 semiconductor nanowires are easily affected by the external gas atmosphere, so both can be used for gas sensing and humidity sensing, and they can play a good synergistic effect through reasonable design. The work functions of ZnO and In2O3 are 5.2 eV and 4.28 eV respectively. When the two are in contact, in order to balance the Fermi level, electrons will transfer from In2O3 to ZnO, causing a contact potential barrier to form at the contact between the two, further reducing the base current. When hydrogen enters the system, hydrogen will react with the oxygen ions adsorbed on the material surface, releasing electrons back into the system and increasing the current. The advantages of the present invention are as follows: Conventional ZnO-ZnO / In2O3-In2O3 homojunctions can also form contact potential barriers, but heterojunctions can provide higher contact potential barriers due to the electron movement at the contact surface caused by different Fermi levels, and can significantly reduce the base current compared with homojunctions. And in a high-temperature hydrogen atmosphere, hydrogen will react with the oxygen ions adsorbed on the ZnO surface, increasing the current; at the same time, hydrogen will react with the exposed O atoms on the ZnO surface, causing metallization behavior on the ZnO surface, which will significantly increase the conductivity of the wire film. In the present invention, ZnO plays a dominant role, so the metallization behavior will bring about a large current change. Combining the above three effects, the ZnO / In2O3 nanowire film can provide a higher current change in the presence and absence of a hydrogen atmosphere, significantly improving the response. On the other hand, when a semiconductor contacts a metal with a high work function to form a Schottky contact, the carrier concentration can also be reduced, improving the sensor sensitivity.

[0024] (2) Based on the different work functions of two semiconductors, ZnO and In2O3, an electron depletion layer is formed at the contact surface in the present invention, increasing the resistance of the sensing base. The contact between the ZnO / In2O3 nanowire film and the high-work-function metal Au can further reduce the carrier concentration of the wire film, thereby strengthening the wire film resistance. And ZnO can undergo metallization behavior in a hydrogen atmosphere, increasing the conductivity of the system, thus generating a greater current change under the conditions of the presence and absence of hydrogen, and obtaining higher response and detection sensitivity.

[0025] (3) The present invention makes full use of the size effect of the high specific surface area of the nanowires with more adsorption sites, and combines the directional movement of carriers caused by the contact of materials with different work functions, thereby further reducing the structural effect of the base current.

[0026] In the present invention, ZnO with different work functions and the contact between the two form a heterojunction. Compared with a homojunction, the heterojunction can provide a greater resistance; the oxygen ions adsorbed on the surface of the heterojunction wire film will react with hydrogen to form water and release electrons in a hydrogen atmosphere, reducing the resistance; moreover, in a hydrogen atmosphere, hydrogen atoms will combine with the exposed O atoms on the surface of ZnO to release electrons to the 2p orbital of O, further reducing the resistance of the wire film. The synergistic effect of the three can result in a large current change before and after hydrogen enters the test environment atmosphere, thereby improving the response and obtaining a lower detection limit at the ppb level. At 300 °C, the response of the device obtained in the present application can reach 2.1 at a hydrogen concentration of 10 ppb, the response time is 120 s at a hydrogen concentration of 10 ppb, and the recovery time is 300 s. And the wire film structure of the present invention maintains the one-dimensional structure of the wire with the characteristic of a large specific surface area, and can maintain its response time. Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of the hydrogen sensor core described in the present invention;

[0028] Figure 2 is an SEM image of the ZnO / In2O3 nanowire film before annealing described in the present invention;

[0029] Figure 3 is the annealed ZnO / In2O3 nanowire film described in the present invention.

[0030] Figure 4 is an SEM image of the ZnO / In2O3 nanowire film after annealing described in the present invention;

[0031] Figure 5 is the ppb-level hydrogen response diagram of the hydrogen sensor described in Example 1 of the present invention. Detailed Embodiments

[0032] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] Next, in combination with the embodiments and drawings of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0034] Embodiment 1:

[0035] As Figure 1 shown, a hydrogen sensor based on a ZnO / In2O3 heterostructure in this Embodiment 1 includes a substrate, a dielectric layer, and a gas sensing layer. Among them, the dielectric layer is disposed on the substrate, the gas sensing layer is disposed on the dielectric layer, the dielectric layer contains a high work function metal, and the gas sensing layer includes a ZnO / In2O3 heterostructure nanowire film and electrodes.

[0036] The molar ratio n(Zn):n(In) in the ZnO / In2O3 heterostructure nanowire film is 90:10.

[0037] The thickness of the dielectric layer is 200 nm;

[0038] The substrate layer selects a quartz wafer;

[0039] The high work function metal selects Au;

[0040] The electrodes in the gas sensing layer are disposed on both sides of the ZnO / In2O3 heterostructure nanowire film, and the high work function metal in the dielectric layer is arranged in a spaced strip shape.

[0041] Connect the hydrogen sensor in this Embodiment 1 to a test platform. After detection, it can be known that at 300 °C, in an atmosphere with hydrogen concentrations of 10 ppb, 20 ppb, and 30 ppb, the hydrogen response at a concentration of 10 ppb is 1.6, the hydrogen response at a concentration of 20 ppb is 2.8, and the hydrogen response at a concentration of 30 ppb is 3.7. Among them, the response time at a hydrogen concentration of 10 ppb is 120 s, and the recovery time is 300 s, as Figure 5 shown.

[0042] Embodiment 2:

[0043] The difference between this embodiment and Embodiment 1 is that n(Zn):n(In) in the ZnO / In2O3 heterostructure nanowire film is 95:5. Under the same hydrogen concentration, the response of the device obtained in this Embodiment 2 is about 52.5% of the device in Embodiment 1.

[0044] Example 3:

[0045] The difference between this example and Example 1 is that the thickness of the dielectric layer is 800 nm. The hydrogen sensor was connected to a test platform. It was detected that at 300 °C, the response of the device at a hydrogen concentration of 10 ppb was about 2.1. Compared with the device in Example 1, the response was increased by 31.3%.

[0046] Example 4:

[0047] The difference between this example and Example 1 is that the thickness of the dielectric layer is 2000 nm. The hydrogen sensor was connected to a test platform. It was detected that at 300 °C, the response of the device at a hydrogen concentration of 10 ppb was about 1.9. Compared with the device in Example 1, the response was increased by 18.8%.

[0048] Example 5:

[0049] The difference between this example and Example 1 is that the thickness of the dielectric layer is 5000 nm. The hydrogen sensor was connected to a test platform. It was detected that at 300 °C, the response of the device at a hydrogen concentration of 10 ppb was about 1.3. Compared with the device in Example 1, the response was about 81.3% of the response in Example 1.

[0050] Example 6:

[0051] The difference between this example and Example 3 is that the high work function metal is selected as Pt. It was detected that at 300 °C, the response of the device at a hydrogen concentration of 10 ppb was about 1.4. Compared with the device in Example 3, the response was about 66.7% of the response in Example 3.

[0052] Example 7:

[0053] A preparation method of the above hydrogen sensor based on the ZnO / In2O3 heterostructure includes the following steps:

[0054] (1) Deposit a high work function metal on the substrate by magnetron sputtering, electron beam deposition or thermal evaporation to form a dielectric layer thin film;

[0055] (2) Add Zn(CH3COO)2·2H2O and In(NO3)3 to DMF and continuously stir for 2.5 h to 3.8 h to obtain solution a; a magnetic stirrer is used during the stirring process, and the stirring process should be carried out in a sealed manner.

[0056] (3) Slowly add PVP (M≈1300000) to solution a and continuously stir until completely dissolved to obtain solution b; the percentage content of salt in solution b is C bsalt , C bsalt = 8.0 - 9.2%; the percentage content of PVP in solution b is Cbpvp , C bpvp = 8.5 - 9.5%. The addition rate of PVP (M≈1300000) shall not exceed 0.5 g / min. A magnetic stirrer is used during the stirring process, and the stirring process shall be carried out in a sealed manner.

[0057] (4) Draw solution b into a syringe and electrospin it onto a dielectric film to synthesize a ZnO / In2O3 nanowire film; after electrospinning, dry it at 60 °C for 24 h to obtain a precursor of the sensor core; during the electrospinning process, the humidity is below 30% and the temperature is below 30 °C; the electrospinning parameters are set as the positive pressure is 20 KV ± 1.5 KV, the negative pressure is 2 KV ± 0.0.5 KV, and the distance between the needle and the receiving plate is 20 cm ± 2.6 cm. When drawing the mixed solution into the syringe during the electrospinning process, avoid the presence of air bubbles in the syringe. The electrospinning is carried out on a sputtered gold quartz wafer (non-conductive).

[0058] (5) Anneal the precursor at an annealing temperature of 600 °C ± 10 °C for an annealing time of 1.8 - 2.5 h and a heating rate of 5 °C / min ± 0.5 to obtain the sensor core;

[0059] (6) Use carbon paste to make electrodes for the sensor core and lead out wires, and heat it at a constant temperature of 70 °C to dry the carbon paste to obtain the hydrogen sensor.

[0060] Figure 2 The electrospinning solution is electrospun onto a quartz substrate with metal electrodes by electrospinning to form an electrospinning solution nanowire film on the substrate; Figure 3 is the final device diagram, and the white surface is the macroscopic diagram of the ZnO / In2O3 heterostructure nanowire film; Figure 4 is the scanning electron microscope image after drying and annealing the electrospinning solution nanowire film to remove organic substances DMF and PVP and convert the Zn / In salts into oxides. It can be seen from the figure that the diameter of the wires becomes smaller and the surface becomes rougher after annealing, but the overall network structure of the wire film remains unchanged. The rough morphology is caused by the evaporation and decomposition of water and inorganic substances during the calcination process.

[0061] And connect the finally prepared hydrogen sensor to the test platform. After testing, it can be known that at 300 °C, in an atmosphere with hydrogen concentrations of 10 ppb, 20 ppb, and 30 ppb, the hydrogen response at a concentration of 10 ppb is 1.6, the hydrogen response at a concentration of 20 ppb is 2.8, and the hydrogen response at a concentration of 30 ppb is 3.7. Among them, the response time at a hydrogen concentration of 10 ppb is 120 s, and the recovery time is 300 s.

[0062] Comparative Example 1:

[0063] The difference between Comparative Example 1 and Example 1 is that the ZnO / In2O3 heterostructure nanowire film does not contain Zn and only contains In2O3. When the hydrogen sensor is connected to the test platform, it can be detected that its detection limit is at the ppm level, and its gas-sensing performance is worse than that of the heterojunction.

[0064] Comparative Example 2:

[0065] The difference between Comparative Example 2 and Example 1 is that the ZnO / In2O3 heterostructure nanowire film does not contain In and only contains ZnO. When the hydrogen sensor is connected to the test platform, it can be detected that its detection limit is at the ppm level, and at a concentration of 10 ppm, its gas-sensing response is less than 1, and its gas-sensing performance is worse than that of the heterojunction.

[0066] Comparative Example 3:

[0067] The difference between Comparative Example 3 and Example 1 is that in the ZnO / In2O3 heterostructure nanowire film, n(Zn):n(In) = 70:30. When the hydrogen sensor is connected to the test platform, it can be detected that the base current of the device decreases significantly, which may be caused by more introduced grain boundary barriers, resulting in a lower response, a higher detection limit, and a response of about 30% in a hydrogen atmosphere with a concentration of 50 ppm.

[0068] Comparative Example 4:

[0069] The difference between Comparative Example 4 and Example 1 is that the thickness of the dielectric layer is 100 nm. When the hydrogen sensor is connected to the test platform, it can be detected that the device is in an unstable state, the test signal has a large noise, and it is not easy to judge whether the signal change is caused by hydrogen.

[0070] Comparative Example 5:

[0071] The difference between Comparative Example 5 and Example 1 is that the thickness of the dielectric layer is 10000 nm. When the hydrogen sensor is connected to the test platform, it can be detected that the base current of the device increases significantly and the response decreases. For hydrogen with a concentration of 10 ppm, its response is about 30%.

[0072] Comparative Example 6:

[0073] The difference between Comparative Example 6 and Example 8 is that the annealing temperature is 400 °C and the annealing time is 2 h. When the hydrogen sensor is connected to the test platform, it can be detected that the base current is in an unstable state and the test signal has a large noise, which may be due to the relatively short annealing time and low temperature, resulting in incomplete decomposition of the organic matter.

[0074] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "thickness", "height", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0075] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0076] In the present invention, unless otherwise clearly defined and limited, the terms such as "mounted", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral molding; unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0078] The present invention is illustrated by the above specific embodiments. Those skilled in the art should understand that various transformations and equivalent substitutions can be made to the present invention without departing from the scope of the present invention. The parts not detailed in the specification of the present invention are well-known technologies to those skilled in the art. In addition, various modifications can be made to the present invention for a specific situation or specific circumstances without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all embodiments falling within the scope of the claims of the present invention.

Claims

1. A method for preparing a hydrogen sensor, characterized in that, It includes the following steps: (1) Deposit a high work function metal on a substrate by magnetron sputtering, electron beam deposition or thermal evaporation to form a dielectric film; (2) Add Zn(CH3COO)2·2H2O and In(NO3)3 to DMF and continuously stir for 2.5 h to 3.8 h to obtain solution a; (3) Slowly add PVP with M≈1300000 to the solution a and continuously stir until completely dissolved to obtain solution b; (4) Draw the solution b into a syringe and spin it on the dielectric film by electrospinning to synthesize a ZnO / In2O3 nanowire film; after electrospinning, dry it at 56 to 66 °C for 20 to 28 h to obtain a precursor of the sensor core; (5) Anneal the precursor at an annealing temperature of 600 °C ± 10 °C, an annealing time of 1.8 to 2.5 h, and a heating rate of 5 °C / min ± 0.5 to obtain the sensor core; (6) Make electrodes for the sensor core with carbon paste and lead out wires, and heat at a constant temperature of 65 to 72 °C to dry the carbon paste to obtain the hydrogen sensor.

2. The preparation method of the hydrogen sensor according to claim 1, wherein, The molar ratio n(Zn):n(In) of the substances in the ZnO / In2O3 nanowire film is 95:5 to 85:

15.

3. The preparation method of the hydrogen sensor according to claim 1, characterized in that, The percentage content of salt in the solution b is C bsalt , C bsalt = 8.0 - 9.2%; the percentage content of PVP in the solution b is C bpvp , C bpvp = 8.5 - 9.5%.

4. The method for preparing a hydrogen sensor according to claim 3, characterized in that, In step (3), the addition rate of the PVP cannot exceed 0.5 g / min.

5. The manufacturing method of the hydrogen sensor according to claim 4, characterized in that, In the electrospinning process of step (4), the humidity is below 30% and the temperature is below 30 °C; the electrospinning parameters are set as a positive pressure of 20 KV ± 1.5 KV, a negative pressure of 2 KV ± 0.05 KV, and a distance between the needle and the receiving plate of 20 cm ± 2.6 cm.

6. The method for preparing a hydrogen sensor according to claim 5, wherein, In steps (2) and (3), a magnetic stirrer is used for the stirring process, and the stirring process should be carried out in a sealed manner.

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