Transition metal doped room temperature hydrogen sensitive material and method of making same

Abstract

The application provides a transition metal doped room temperature hydrogen sensitive material and a preparation method thereof, and belongs to the technical field of semiconductor gas sensor materials. In view of the problems of high-temperature work, slow response speed, complex preparation process and serious pollution of the existing hydrogen sensor, the transition metal doped room temperature hydrogen sensitive material is prepared through a hydrothermal synthesis combined with a hydrobromic acid assisted ion exchange process. The response value of the material to 5000 ppm hydrogen gas reaches 65.4% at room temperature, and the response / recovery time is only 6 seconds / 36 seconds. Meanwhile, the environmentally friendly process is used to replace the strong corrosive acid, and the cost is reduced by 80%, so that the material is suitable for high-sensitivity and rapid leakage monitoring of hydrogen energy storage and transportation facilities.

Description

Technical Field

[0001] This invention relates to the field of semiconductor gas sensor materials technology, and in particular to a room temperature hydrogen-sensitive material based on transition metal doping and its preparation method. Background Technology

[0002] Hydrogen sensors have important applications in the field of hydrogen energy safety monitoring, but traditional technologies have significant drawbacks. For example, SnO2-based sensors need to operate at temperatures above 200°C, relying on external heating modules, which leads to high energy consumption and safety hazards; their response / recovery time typically exceeds 60 seconds, making it difficult to meet real-time monitoring requirements.

[0003] The modification of existing niobium pentoxide (Nb₂O₅)-based sensors mostly relies on doping with noble metals (such as Pt and Pd), which is costly and requires the use of concentrated hydrochloric acid or nitric acid in the preparation process, resulting in serious acid mist pollution and residual Cl. - It also reduces material stability. Related research indicates that nanowire structures can be prepared by treating with hydrochloric acid, but Cl... - Complete removal is difficult, and strong acid operation poses a high risk. Currently, there are no reports of Nb2O5-based hydrogen-sensitive materials using hydrobromic acid (HBr)-assisted ion exchange combined with nickel chloride thermal decomposition doping technology, and there is also a lack of solutions to enhance room-temperature hydrogen-sensitive performance through the synergistic effect of heterojunctions and mesophases.

[0004] Therefore, there is an urgent need to develop a hydrogen-sensitive material that operates at room temperature, responds quickly, is environmentally friendly, and is low in cost. Summary of the Invention

[0005] This invention provides a room-temperature hydrogen-sensitive material based on transition metal doping and its preparation method, which solves the defects of existing technologies such as high temperature dependence, slow response speed, complex preparation process, pollution and high cost.

[0006] On one hand, the present invention provides a method for preparing a room-temperature hydrogen-sensitive material based on transition metal doping, characterized by comprising the following steps:

[0007] (1) Niobium powder, NaOH and deionized water were added to a hydrothermal reactor for hydrothermal reaction. After washing until pH=7, the mixture was dried under vacuum to obtain sodium niobate precursor.

[0008] (2) The precursor was immersed in hydrobromic acid solution and stirred, and then allowed to stand to react, resulting in niobic acid precipitate;

[0009] (3) NiCl2·6H2O was added and mixed with niobic acid precipitate and ground, followed by annealing to obtain room temperature hydrogen-sensitive material based on transition metal doping;

[0010] In step (1), the mass ratio of niobium powder, NaOH and deionized water is 1:(50~90):(150~240);

[0011] In step (2), the concentration of the hydrobromic acid solution is 1.95~2.05M;

[0012] In step (3), the mass ratio of NiCl2·6H2O to niobic acid precipitate is 1:2~5.

[0013] According to the present invention, a method for preparing a room temperature hydrogen-sensitive material based on transition metal doping is provided. In step (1), the temperature of the hydrothermal reaction is 110~150℃ and the time of the hydrothermal reaction is 12~48 hours.

[0014] According to the preparation method of room temperature hydrogen-sensitive material based on transition metal doping provided by the present invention, in step (2), the stirring time is 7-11 hours and the standing reaction time is 6-10 hours.

[0015] According to the preparation method of room temperature hydrogen-sensitive material based on transition metal doping provided by the present invention, in step (3), the grinding time is 8 to 12 minutes.

[0016] According to the preparation method of room temperature hydrogen-sensitive material based on transition metal doping provided by the present invention, in step (3), the annealing treatment is carried out in an argon atmosphere, the annealing temperature is 700~1100℃, and the annealing time is 2~6 hours.

[0017] On the other hand, the present invention also provides a room temperature hydrogen-sensitive material based on transition metal doping, which is prepared by a method for preparing room temperature hydrogen-sensitive materials based on transition metal doping.

[0018] According to the present invention, a room-temperature hydrogen-sensitive material based on transition metal doping is provided, wherein the room-temperature hydrogen-sensitive material based on transition metal doping is composed of a Ni-doped Nb2O5 matrix and forms an Nb2O5 / NiNb2O6 heterojunction and (NiNb2O6). 0.6667 It is an intermediate phase and has a nanowire structure.

[0019] According to the present invention, a room-temperature hydrogen-sensitive material based on transition metal doping is provided, wherein the diameter of the nanowire structure is 50~80nm and the length of the nanowire structure is 5~12μm.

[0020] On the other hand, the present invention also provides a hydrogen sensor comprising a room temperature hydrogen-sensitive material based on transition metal doping as a sensitive film, wherein the thickness of the sensitive film formed on the surface of the hydrogen sensor is 4~6 μm.

[0021] On the other hand, the present invention also provides a method for preparing a hydrogen sensor, comprising the following steps:

[0022] (1) Disperse the room temperature hydrogen-sensitive material based on transition metal doping in ethanol to obtain a dispersion;

[0023] (2) The dispersion was drop-coated onto the surface of the interdigitated electrode and dried to obtain a hydrogen sensor;

[0024] The interdigitated electrode is a Ti / Pt electrode;

[0025] The drying temperature is 70~110℃, and the drying time is 20~60 minutes.

[0026] The present invention provides a room-temperature hydrogen-sensitive material based on transition metal doping and its preparation method, which uses hydrobromic acid (HBr) instead of a highly corrosive acid, and produces environmentally friendly byproducts NaBr and H2O, thus avoiding acid mist pollution.

[0027] This invention provides a room-temperature hydrogen-sensitive material based on transition metal doping and its preparation method, which forms Nb₂O₅ / NiNb₂O₆ heterojunctions and (NiNb₂O₆) through Ni doping. 0.6667 The mesophase synergistically enhances the surface electron depletion effect, achieving a response value of 65.4% to 5000ppmH2 at room temperature.

[0028] The present invention provides a room-temperature hydrogen-sensitive material based on transition metal doping and its preparation method, which forms a nanowire structure, provides a high specific surface area and gas diffusion channels, and has a response / recovery time of only 6 seconds / 36 seconds.

[0029] The present invention provides a room-temperature hydrogen-sensitive material based on transition metal doping and its preparation method. This method avoids the use of precious metals through a NiCl2 thermal decomposition doping process, reducing costs by 80%, and Cl... - Complete removal ensures material stability. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the hydrogen sensor provided in an embodiment of the present invention;

[0032] Figure 2 This is a process flow diagram of the preparation process of room temperature hydrogen-sensitive materials based on transition metal doping provided in the embodiments of the present invention;

[0033] Figure 3 This is the XRD pattern of the room-temperature hydrogen-sensitive material based on transition metal doping provided in the embodiments of the present invention;

[0034] Figure 4 This is one of the SEM images of the nanowire structure in the room-temperature hydrogen-sensitive material based on transition metal doping provided in the embodiments of the present invention;

[0035] Figure 5 This is the second SEM image of the nanowire structure in the room-temperature hydrogen-sensitive material based on transition metal doping provided in this embodiment of the invention.

[0036] Figure 6 This is the response / recovery curve of the hydrogen sensor provided in this embodiment of the invention;

[0037] Figure label:

[0038] 1. Ti / Pt interdigitated electrode; 2. SiO2 substrate. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] This invention provides a method for preparing room-temperature hydrogen-sensitive materials based on transition metal doping, comprising the following steps:

[0041] (1) Niobium powder, NaOH and deionized water were added to a hydrothermal reactor for hydrothermal reaction. After washing until pH=7, the mixture was dried under vacuum to obtain sodium niobate precursor.

[0042] (2) The precursor was immersed in hydrobromic acid solution and stirred, and then allowed to stand to react, resulting in niobic acid precipitate;

[0043] (3) NiCl2·6H2O was added and mixed with niobic acid precipitate and ground, followed by annealing to obtain room temperature hydrogen-sensitive material based on transition metal doping;

[0044] In step (1), the mass ratio of niobium powder, NaOH and deionized water is 1:(50~90):(150~240), preferably 1:(60~80):(160~220), and more preferably 1:(65~75):(165~200);

[0045] In step (2), the concentration of the hydrobromic acid solution is 1.95~2.05M;

[0046] In step (3), the mass ratio of NiCl2·6H2O to niobic acid precipitate is 1:2~5, preferably 1:2.5~4, and more preferably 1:3~3.5.

[0047] In this invention, in step (1), the temperature of the hydrothermal reaction is 110~150℃, preferably 120~140℃, and more preferably 125~135℃; the time of the hydrothermal reaction is 12~48 hours, preferably 18~36 hours, and more preferably 24~30 hours.

[0048] In this invention, in step (2), the stirring time is 7 to 11 hours, preferably 8 to 10 hours, and more preferably 8.5 to 9.5 hours; the standing reaction time is 6 to 10 hours, preferably 7 to 9 hours, and more preferably 7.5 to 8.5 hours.

[0049] In this invention, in step (3), the grinding time is 8 to 12 minutes, preferably 9 to 11 minutes, and more preferably 9.5 to 10.5 minutes.

[0050] In this invention, in step (3), the annealing treatment is carried out in an argon atmosphere, the annealing temperature is 700~1100℃, preferably 750~1000℃, and more preferably 800~900℃; the annealing time is 2~6 hours, preferably 2.5~5 hours, and more preferably 3~4 hours.

[0051] The present invention also provides a room temperature hydrogen-sensitive material based on transition metal doping, which is prepared by a method for preparing room temperature hydrogen-sensitive materials based on transition metal doping.

[0052] In this invention, the room-temperature hydrogen-sensitive material based on transition metal doping is composed of a Ni-doped Nb2O5 matrix, forming an Nb2O5 / NiNb2O6 heterojunction and (NiNb2O6). 0.6667 It is an intermediate phase and has a nanowire structure.

[0053] In this invention, the diameter of the nanowire structure is 50-80 nm, preferably 55-75 nm, and more preferably 60-70 nm; the length of the nanowire structure is 5-12 μm, preferably 7-10 μm.

[0054] The present invention also provides a hydrogen sensor comprising a room temperature hydrogen-sensitive material based on transition metal doping as a sensitive film, wherein the thickness of the sensitive film formed on the surface of the hydrogen sensor is 4~6 μm.

[0055] This invention also provides a method for preparing a hydrogen sensor, comprising the following steps:

[0056] (1) Disperse the room temperature hydrogen-sensitive material based on transition metal doping in ethanol to obtain a dispersion;

[0057] (2) The dispersion was drop-coated onto the surface of the interdigitated electrode and dried to obtain a hydrogen sensor;

[0058] The interdigitated electrode is a Ti / Pt electrode;

[0059] The drying temperature is 70~110℃, preferably 80~100℃, and more preferably 85~110℃; the drying time is 20~60 minutes, preferably 25~50 minutes, and more preferably 30~40 minutes.

[0060] The following is combined with Figures 1-6 The present invention describes a room-temperature hydrogen-sensitive material based on transition metal doping and its preparation method.

[0061] Figure 1 This is a schematic diagram of the structure of the hydrogen sensor provided in an embodiment of the present invention.

[0062] like Figure 1 As shown, the sensor includes a Ti / Pt interdigitated electrode with an electrode spacing of 100 μm and a sensitive film covering its surface; and a SiO2 substrate for supporting the interdigitated electrode. This structure detects hydrogen concentration by measuring the resistance change of the interdigitated electrode, exhibiting high sensitivity and fast response characteristics.

[0063] Figure 2 This is a process flow diagram of the preparation process of room temperature hydrogen-sensitive materials based on transition metal doping provided in the embodiments of the present invention.

[0064] like Figure 2 As shown, the preparation process includes: mixing niobium powder, NaOH, and deionized water in a certain proportion, hydrothermally reacting at 110-150℃ for 12-48 hours, and obtaining a precursor after washing and drying; immersing the precursor in a 1.95-2.05MHBr solution and stirring for 7-11 hours, and allowing it to stand to form niobic acid precipitate; mixing and grinding NiCl2·6H2O with the precipitate, and annealing at 700-1100℃ for 2-6 hours under an argon atmosphere; and then... - The material is removed by HCl to form a Ni-doped Nb2O5 / NiNb2O6 heterojunction; the material is then dispersed and drop-coated onto the surface of the interdigitated electrode, and dried to form a sensitive film.

[0065] Figure 3 This is the XRD pattern of a room-temperature hydrogen-sensitive material based on transition metal doping provided in an embodiment of the present invention.

[0066] like Figure 3As shown in the spectrum, the characteristic peaks of the Nb₂O₅ phase (JCPDS27-1003) are clearly visible: 2θ = 22.5°, 28.3°, 36.5°, etc.; and the characteristic peaks of the NiNb₂O₆ phase (JCPDS34-0421) are visible: 2θ = 24.8°, 33.1°, 49.7°, etc.; (NiNb₂O₆) 0.6667 Intermediate phase: Non-standard peaks such as 2θ=25.6° and 37.2° indicate that nickel doping leads to lattice distortion and the formation of high-density oxygen vacancies. The three-phase coexistence structure significantly enhances the surface electron depletion effect of the material through the synergistic effect of the heterojunction and the intermediate phase.

[0067] Figure 4 and Figure 5 This is a SEM image of the nanowire structure in the room-temperature hydrogen-sensitive material based on transition metal doping provided in this embodiment of the invention.

[0068] like Figure 4 As shown, the material exhibits a uniform nanowire structure with a diameter of 50-80 nm and a length of 5-12 μm; Figure 5 Further analysis revealed that the nanowires have smooth surfaces and are cross-linked, forming a porous network. The high specific surface area provides a rapid channel for hydrogen adsorption and diffusion, a key factor in the short response time.

[0069] Figure 6 This is the response / recovery curve of the hydrogen sensor provided in this embodiment of the invention.

[0070] like Figure 6 As shown, under conditions of 25°C and 5000 ppm H2, the resistance value decreased to 34.6% of the initial value within 6 seconds during the response phase; and the resistance value recovered to 90% of the initial value within 36 seconds during the recovery phase. The rapid response and recovery performance is attributed to the efficient gas diffusion of the nanowire structure and the rapid charge transfer of the Schottky barrier at the heterojunction interface.

[0071] Example 1

[0072] Take 0.24 g of niobium powder, 16.67 g of NaOH, and 40 mL of deionized water, mix them, and transfer them to a hydrothermal reactor. React hydrothermally at 130 °C for 24 hours. After the reaction, wash with deionized water until pH=7, and dry under vacuum at 60 °C for 12 hours to obtain the sodium niobate precursor.

[0073] The precursor was immersed in 2M hydrobromic acid solution and magnetically stirred for 9 hours, followed by standing for 8 hours. The precipitate was collected by filtration, washed three times with deionized water, and dried at 60°C to obtain niobic acid precipitate.

[0074] NiCl₂·6H₂O and niobic acid precipitate were mixed at a mass ratio of 1:3 and ground for 10 minutes until homogeneous. The mixture was placed in a tube furnace and annealed at 800°C for 3 hours under an argon atmosphere, with a heating rate of 5°C / min. After annealing, it was allowed to cool naturally to obtain a room-temperature hydrogen-sensitive material based on transition metal doping.

[0075] Testing revealed that the room-temperature hydrogen-sensitive material based on transition metal doping formed a nanowire structure with a diameter of 60-70 nm and a length of 8-10 μm.

[0076] A room-temperature hydrogen-sensitive material based on transition metal doping was dispersed in ethanol, ultrasonicated for 30 minutes, and then drop-coated onto the surface of a Ti / Pt interdigitated electrode at a spacing of 100 μm.

[0077] The hydrogen sensor was obtained by drying the membrane at 80°C for 30 minutes to form a 5μm thick sensitive membrane.

[0078] The hydrogen sensor provided in this embodiment was tested at 25°C, 50% relative humidity, and 5000 ppm H2. The response value was 65.4%, the response time was 6 seconds, the recovery time was 36 seconds, the detection limit was 300 ppm, the humidity interference was ±35%, and the response value decayed by <5% after 30 days of continuous operation.

[0079] Example 2

[0080] Take 0.24 g of niobium powder, 18 g of NaOH, and 45 mL of deionized water, mix them, and transfer them to a hydrothermal reactor. React hydrothermally at 120 °C for 36 hours. After the reaction, wash with deionized water until pH=7, and dry under vacuum at 60 °C for 12 hours to obtain the sodium niobate precursor.

[0081] The precursor was immersed in 1.98M hydrobromic acid solution and magnetically stirred for 8 hours, followed by standing for 7 hours. The precipitate was collected by filtration, washed three times with deionized water, and dried at 60°C to obtain niobic acid precipitate.

[0082] NiCl₂·6H₂O and niobic acid precipitate were mixed at a mass ratio of 1:4 and ground for 12 minutes until homogeneous. The mixture was placed in a tube furnace and annealed at 750°C for 4 hours under an argon atmosphere, with a heating rate of 3°C / min. After annealing, it was allowed to cool naturally to obtain a room-temperature hydrogen-sensitive material based on transition metal doping.

[0083] Testing revealed that the room-temperature hydrogen-sensitive material based on transition metal doping formed a nanowire structure with a diameter of 55-65 nm and a length of 6-9 μm.

[0084] A room-temperature hydrogen-sensitive material based on transition metal doping was dispersed in ethanol, ultrasonicated for 30 minutes, and then drop-coated onto the surface of a Ti / Pt interdigitated electrode at a spacing of 100 μm.

[0085] The hydrogen sensor was obtained by drying the membrane at 90°C for 40 minutes to form a sensitive membrane with a thickness of 4.5 μm.

[0086] The hydrogen sensor provided in this embodiment was tested at 25°C, 50% relative humidity, and 5000 ppm H2. The response value was 63.8%, the response time was 7 seconds, the recovery time was 38 seconds, the detection limit was 320 ppm, the humidity interference was ±38%, and the response value decayed by <6% after 30 days of continuous operation.

[0087] Example 3

[0088] Take 0.24 g of niobium powder, 14 g of NaOH, and 35 mL of deionized water, mix them, and transfer them to a hydrothermal reactor. React hydrothermally at 140 °C for 18 hours. After the reaction, wash with deionized water until pH=7, and dry under vacuum at 60 °C for 12 hours to obtain the sodium niobate precursor.

[0089] The precursor was immersed in 2.02M hydrobromic acid solution and magnetically stirred for 10 hours, followed by standing for 9 hours. The precipitate was collected by filtration, washed three times with deionized water, and dried at 60°C to obtain niobic acid precipitate.

[0090] NiCl₂·6H₂O and niobic acid precipitate were mixed at a mass ratio of 1:2.5 and ground for 9 minutes until homogeneous. The mixture was placed in a tube furnace and annealed at 850°C for 2.5 hours under an argon atmosphere, with a heating rate of 8°C / min. After annealing, it was allowed to cool naturally to obtain a room-temperature hydrogen-sensitive material based on transition metal doping.

[0091] Testing revealed that the room-temperature hydrogen-sensitive material based on transition metal doping formed a nanowire structure with a diameter of 70-80 nm and a length of 10-12 μm.

[0092] A room-temperature hydrogen-sensitive material based on transition metal doping was dispersed in ethanol, ultrasonicated for 30 minutes, and then drop-coated onto the surface of a Ti / Pt interdigitated electrode at a spacing of 100 μm.

[0093] The hydrogen sensor was obtained by drying the membrane at 100°C for 25 minutes to form a 6μm thick sensitive membrane.

[0094] The hydrogen sensor provided in this embodiment was tested at 25°C, 50% relative humidity, and 5000 ppm H2. The response value was 67.1%, the response time was 5 seconds, the recovery time was 34 seconds, the detection limit was 280 ppm, the humidity interference was ±32%, and the response value decayed by <4% after 30 days of continuous operation.

[0095] Example 4

[0096] Take 0.24 g of niobium powder, 20 g of NaOH, and 50 mL of deionized water, mix them, and transfer them to a hydrothermal reactor. React hydrothermally at 115 °C for 48 hours. After the reaction, wash with deionized water until pH=7, and dry under vacuum at 60 °C for 12 hours to obtain the sodium niobate precursor.

[0097] The precursor was immersed in 1.95M hydrobromic acid solution and magnetically stirred for 7 hours, followed by standing for 10 hours. The precipitate was collected by filtration, washed three times with deionized water, and dried at 60°C to obtain niobic acid precipitate.

[0098] NiCl₂·6H₂O and niobic acid precipitate were mixed at a mass ratio of 1:5 and ground for 8 minutes until homogeneous. The mixture was placed in a tube furnace and annealed at 900°C for 5 hours under an argon atmosphere, with a heating rate of 4°C / min. After annealing, it was allowed to cool naturally to obtain a room-temperature hydrogen-sensitive material based on transition metal doping.

[0099] Testing revealed that the room-temperature hydrogen-sensitive material based on transition metal doping formed a nanowire structure with a diameter of 50-60 nm and a length of 5-7 μm.

[0100] A room-temperature hydrogen-sensitive material based on transition metal doping was dispersed in ethanol, ultrasonicated for 30 minutes, and then drop-coated onto the surface of a Ti / Pt interdigitated electrode at a spacing of 100 μm.

[0101] The hydrogen sensor was obtained by drying the membrane at 70°C for 60 minutes to form a sensitive membrane with a thickness of 4μm.

[0102] The hydrogen sensor provided in this embodiment was tested at 25°C, 50% relative humidity, and 5000 ppm H2. The response value was 60.2%, the response time was 8 seconds, the recovery time was 40 seconds, the detection limit was 350 ppm, the humidity interference was ±42%, and the response value decayed by <8% after 30 days of continuous operation.

[0103] Example 5

[0104] Take 0.24 g of niobium powder, 15 g of NaOH, and 38 mL of deionized water, mix them, and transfer them to a hydrothermal reactor. React hydrothermally at 150 °C for 12 hours. After the reaction, wash with deionized water until pH=7, and dry under vacuum at 60 °C for 12 hours to obtain the sodium niobate precursor.

[0105] The precursor was immersed in 2.05M hydrobromic acid solution and magnetically stirred for 11 hours, followed by standing for 6 hours. The precipitate was collected by filtration, washed three times with deionized water, and dried at 60°C to obtain niobic acid precipitate.

[0106] NiCl₂·6H₂O and niobic acid precipitate were mixed at a mass ratio of 1:3.5 and ground for 11 minutes until homogeneous. The mixture was placed in a tube furnace and annealed at 700°C for 6 hours under an argon atmosphere, with a heating rate of 2°C / min. After annealing, it was allowed to cool naturally to obtain a room-temperature hydrogen-sensitive material based on transition metal doping.

[0107] Testing revealed that the room-temperature hydrogen-sensitive material based on transition metal doping formed a nanowire structure with a diameter of 75-80 nm and a length of 11-12 μm.

[0108] A room-temperature hydrogen-sensitive material based on transition metal doping was dispersed in ethanol, ultrasonicated for 30 minutes, and then drop-coated onto the surface of a Ti / Pt interdigitated electrode at a spacing of 100 μm.

[0109] The hydrogen sensor was obtained by drying the membrane at 110°C for 20 minutes to form a 4μm thick sensitive membrane.

[0110] The hydrogen sensor provided in this embodiment was tested at 25°C, 50% relative humidity, and 5000 ppm H2. The response value was 62.5%, the response time was 6.5 seconds, the recovery time was 37 seconds, the detection limit was 310 ppm, the humidity interference was ±37%, and the response value decayed by <5% after 30 days of continuous operation.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a room-temperature hydrogen-sensitive material based on transition metal doping, characterized in that, Includes the following steps: (1) Niobium powder, NaOH and deionized water were added to a hydrothermal reactor for hydrothermal reaction. After washing until pH=7, the mixture was dried under vacuum to obtain sodium niobate precursor. (2) The precursor was immersed in hydrobromic acid solution and stirred, and then allowed to stand to react, resulting in niobic acid precipitate; (3) NiCl2·6H2O was added and mixed with niobic acid precipitate and ground, followed by annealing to obtain room temperature hydrogen-sensitive material based on transition metal doping; In step (1), the mass ratio of niobium powder, NaOH and deionized water is 1:(50~90):(150~240); In step (2), the concentration of the hydrobromic acid solution is 1.95~2.05M; In step (3), the mass ratio of NiCl2·6H2O to niobic acid precipitate is 1:2~5; The room-temperature hydrogen-sensitive material based on transition metal doping is composed of a Ni-doped Nb2O5 matrix, forming an Nb2O5 / NiNb2O6 heterojunction and (NiNb2O6). 0.6667 It is an intermediate phase and has a nanowire structure; The nanowire structure has a diameter of 50~80nm and a length of 5~12μm.

2. The method for preparing room-temperature hydrogen-sensitive materials based on transition metal doping according to claim 1, characterized in that, In step (1), the temperature of the hydrothermal reaction is 110~150℃ and the time of the hydrothermal reaction is 12~48 hours.

3. The method for preparing room-temperature hydrogen-sensitive materials based on transition metal doping according to claim 1, characterized in that, In step (2), the stirring time is 7 to 11 hours and the standing reaction time is 6 to 10 hours.

4. The method for preparing room-temperature hydrogen-sensitive materials based on transition metal doping according to claim 1, characterized in that, In step (3), the grinding time is 8 to 12 minutes.

5. The method for preparing room-temperature hydrogen-sensitive materials based on transition metal doping according to claim 1, characterized in that, In step (3), the annealing process is carried out in an argon atmosphere, the annealing temperature is 700~1100℃, and the annealing time is 2~6 hours.

6. A room-temperature hydrogen-sensitive material based on transition metal doping, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 5.

7. A hydrogen sensor, characterized in that, The sensor comprises a room-temperature hydrogen-sensitive material based on transition metal doping as described in claim 6 as a sensitive membrane, wherein the thickness of the sensitive membrane formed on the surface of the hydrogen sensor is 4~6 μm.

8. The method for preparing a hydrogen sensor as described in claim 7, characterized in that, Includes the following steps: (1) Disperse the room temperature hydrogen-sensitive material based on transition metal doping in ethanol to obtain a dispersion; (2) The dispersion was drop-coated onto the surface of the interdigitated electrode and dried to obtain a hydrogen sensor; The interdigitated electrode is a Ti / Pt electrode; The drying temperature is 70~110℃, and the drying time is 20~60 minutes.

Images