Hydrogen sulfide gas sensor and method for detecting concentration of hydrogen sulfide in gas

Abstract

The invention relates to the field of gas sensors, and discloses a hydrogen sulfide gas sensor and a method for detecting the concentration of hydrogen sulfide in gas. The hydrogen sulfide gas sensor comprises a substrate and a gas sensitive material, a cavity is formed in the substrate, the gas-sensitive material is located above the cavity, and the two ends of the gas-sensitive material are connected with the gold electrodes on the substrate; the gas sensitive material comprises graphene fiber and metal oxide loaded on the graphene fiber. The metal oxide is selected from one or more than two of oxides of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg and Al; the specific surface area of the gas sensitive material is 80-150m < 2 > / g; the loading capacity of the metal oxide is 0.05 to 5 weight percent. The hydrogen sulfide gas sensor can be self-heated, has high sensitivity to hydrogen sulfide gas, and is suitable for being applied to the field of gas monitoring.

Description

Technical Field

[0001] The invention relates to the field of gas sensors, and in particular to a hydrogen sulfide gas sensor and a method for detecting the concentration of hydrogen sulfide in gas. Background Art

[0002] In recent years, as people's attention to the environment, safety and health has gradually increased, research on gas sensors that can accurately monitor toxic and harmful gases has also begun to heat up. As a widely used gas sensor, resistive gas sensors can convert gas concentration signals into electrical signals through the resistance changes generated by the reaction between oxygen anions on the device surface and the target gas, thereby monitoring and analyzing the concentration of toxic and harmful gases. Common gas-sensitive materials used to prepare resistive gas sensors are nano-metal oxides, including nano-iron trioxide (Fe 2 O 3 ), tin dioxide (SnO 2 ), tungsten trioxide (WO 3 ), molybdenum trioxide (MoO 3 ), copper oxide (CuO), zinc oxide (ZnO), etc. However, due to the disadvantage of low room temperature conductivity of metal oxides, metal oxide-based gas sensors need to be heated to 200-400°C to work properly. According to statistics, nearly 60% of the energy of the sensor is used to heat the gas-sensitive material, which not only increases energy consumption, but also is not conducive to the miniaturization and long-term use of gas sensors, and also brings safety hazards. Therefore, how to prepare sensors with low energy consumption and excellent gas-sensitive performance has become one of the hot topics in the field of gas sensors in recent years.

[0003] Common graphene materials can be divided into one-dimensional nanofibers, two-dimensional nanofilms and three-dimensional graphene spheres according to their dimensions. One-dimensional graphene fibers have great development potential in the fields of energy, catalysis and sensing due to their good flexibility, conductivity and processability. However, pure-phase graphene fibers have a single surface structure and few functional groups, which limits their further application.

[0004] At present, one-dimensional graphene / metal oxide gas sensors still have problems such as low sensitivity and slow response speed at room temperature and cannot meet people's needs in real life. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of the prior art hydrogen sulfide gas sensor, such as large size, high energy consumption, low sensitivity, slow response speed, etc., and to provide a hydrogen sulfide gas sensor and a method for detecting the concentration of hydrogen sulfide in gas. The hydrogen sulfide gas sensor of the present invention can be self-heated, does not require an external heating element, is easy to process and realizes miniaturization of the circuit, and has high sensitivity to hydrogen sulfide gas, and is very suitable for application in the field of gas monitoring.

[0006] In order to achieve the above object, the present invention provides a hydrogen sulfide gas sensor on one hand, wherein the hydrogen sulfide gas sensor comprises a substrate and a gas-sensitive material;

[0007] A cavity is provided on the substrate, the gas-sensitive material is located above the cavity, and two ends of the gas-sensitive material are connected to gold electrodes on the substrate;

[0008] The gas-sensitive material comprises graphene fibers and metal oxides supported on the graphene fibers;

[0009] The metal oxide is selected from one or more of the oxides of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg and Al;

[0010] The specific surface area of ​​the gas-sensitive material is 80-150 m 2 / g;

[0011] Based on the total weight of the gas-sensitive material, the loading amount of the metal oxide is 0.05-5wt%.

[0012] Preferably, the substrate is a MEMS chip.

[0013] Preferably, the gas-sensitive material is connected to the gold electrode via a conductive silver paste.

[0014] Preferably, the method for preparing the gas-sensitive material comprises the following steps:

[0015] (1) mixing alginate, graphene oxide and water to obtain a mixed dispersion;

[0016] (2) mixing the mixed dispersion with a solution containing calcium ions to obtain graphene oxide hydrogel fibers;

[0017] (3) soaking the graphene oxide hydrogel fiber in a metal salt solution and then sintering it;

[0018] The metal salt is selected from one or more of salts of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg and Al.

[0019] Preferably, the weight ratio of graphene oxide to alginate is 1:0.8-10:5-50.

[0020] Preferably, in the mixed dispersion, the mass concentration of the alginate is 0.01-5%;

[0021] Preferably, in the mixed dispersion, the concentration of graphene oxide is 1-15 mg / mL.

[0022] Preferably, the concentration of the metal salt in the metal salt solution is 0.05-0.2 mol / L.

[0023] A second aspect of the present invention provides a method for detecting the concentration of hydrogen sulfide in a gas, the method comprising: applying a working voltage to a hydrogen sulfide gas sensor, and then placing the sensor in a gas containing hydrogen sulfide for detection;

[0024] Wherein, the operating voltage is 0.1-20V;

[0025] The hydrogen sulfide gas sensor is the hydrogen sulfide gas sensor mentioned above.

[0026] Preferably, in the gas containing hydrogen sulfide, the concentration of hydrogen sulfide is 0.5-50 ppm.

[0027] The hydrogen sulfide gas sensor of the present invention obtains a gas-sensitive material by compounding one-dimensional graphene fiber and metal oxide, and the gas-sensitive material has high electrical conductivity and excellent electrical conductivity, and the gas-sensitive material has a large specific surface area and a large number of active sites on the surface, so the hydrogen sulfide gas sensor of the present invention has high sensitivity to hydrogen sulfide gas, a lower detection limit, and a fast response speed, and can be well applied to the detection of hydrogen sulfide gas. In addition, the hydrogen sulfide gas sensor of the present invention can realize the self-heating function through Joule's law, without the need to add additional heating elements, and better realize the miniaturization of the device. The process of the hydrogen sulfide gas sensor is simpler, and the gas-sensitive material can be directly bonded without the need for coating or grinding operations, and thanks to the gas-sensitive material being a one-dimensional graphene fiber, the hydrogen sulfide gas sensor can be more convenient to integrate and has a larger integrated amount. Further, the hydrogen sulfide gas sensor further reduces heat dissipation and reduces the energy consumption of the overall device by setting a hollow substrate, truly realizing low-energy rapid detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the hydrogen sulfide gas sensor of the present invention;

[0029] Figure 2 is a SEM morphology image of the gas-sensitive material described in Example 1 of the present invention;

[0030] Figure 3 is a SEM morphology image of the gas-sensitive material described in Example 2 of the present invention;

[0031] Figure 4 This is a SEM morphology image of the gas-sensitive material described in Example 3 of the present invention.

[0032] Description of Reference Numerals

[0033] 1. Substrate; 2. Gas-sensitive material; 3. Gold electrode; 4. Conductive silver paste. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0035] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0036] In the present invention, the hydrogen sulfide gas sensor comprises a substrate 1 and a gas-sensitive material 2; the structural schematic diagram of the hydrogen sulfide gas sensor is as shown in Figure 1 As shown, a cavity is provided on the substrate 1 , the gas-sensitive material 2 is located above the cavity, and two ends of the gas-sensitive material 2 are connected to gold electrodes 3 on the substrate 1 .

[0037] In the present invention, the gas-sensitive material 2 is suspended above the cavity of the substrate 1, and the ends of the gas-sensitive material 2 can be connected to the gold electrodes 3 through wires, so that the current can effectively pass through the gas-sensitive material 2. In addition, the gas-sensitive material 2 further realizes the self-heating function through Joule's law. When the hydrogen sulfide gas sensor is self-heated, the cavity below the gas-sensitive material 2 can significantly reduce the heat dissipation of the gas-sensitive material 2, reduce the heat loss of the hydrogen sulfide gas sensor, and further reduce the energy loss of the gas sensor, thereby realizing low-energy detection. In addition, the hydrogen sulfide gas sensor described in the present invention does not need to be equipped with an additional external heating element, which further simplifies the structure of the gas sensor, reduces the volume of the gas sensor, and realizes the miniaturization of the device.

[0038] In the present invention, the gas-sensitive material 2 comprises graphene fibers and metal oxides supported on the graphene fibers; the metal oxides are selected from one or more of oxides of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg, and Al. The gas-sensitive material is a one-dimensional graphene fiber composite material. By compounding one-dimensional graphene fibers with metal oxides, the conductivity of the gas-sensitive material 2 can be significantly improved, thereby further enhancing the self-heating performance of the gas-sensitive material 2. Additionally, by loading the metal oxides, the active sites of the gas-sensitive material are further increased.

[0039] In a preferred embodiment, in order to further improve the performance of the gas-sensitive material 2 and save its preparation cost, the metal oxides are selected from one or more of Zn, Cu, Co, Fe, and Mn.

[0040] In a specific embodiment, the specific surface area of the gas-sensitive material 2 is 80 - 150 m 2 / g. Based on the total weight of the graphene-metal oxide composite fiber, the loading amount of the metal oxide is 0.05 - 5 wt%, preferably 0.8 - 4 wt%. The gas-sensitive material 2 of the present invention has a large specific surface area and a higher loading amount of the metal oxide. Therefore, the gas-sensitive material of the present invention can provide more active sites, so that on the premise of having excellent self-heating performance, the sensitivity to hydrogen sulfide gas can be further improved, the detection limit of sulfide gas is lower, and the response speed is faster.

[0041] In the present invention, the substrate 1 can be a substrate of a common gas sensor in the art and is used as a support for the gas-sensitive material 2. Preferably, the substrate 1 is a MEMS chip.

[0042] In the present invention, both ends of the gas-sensitive material 2 can be connected to the gold electrode 3 by common methods in the art. Preferably, the gas-sensitive material 2 is connected to the gold electrode 3 through a conductive silver paste 4.

[0043] In the present invention, the preparation method of the gas-sensitive material 2 comprises the following steps:

[0044] (1) Mix alginate with graphene oxide and water to obtain a mixed dispersion;

[0045] (2) Mix the mixed dispersion with a solution containing calcium ions to obtain graphene oxide hydrogel fibers;

[0046] (3) Immerse the graphene oxide hydrogel fibers in a metal salt solution and then perform sintering;

[0047] The metal salt is selected from one or more of salts of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg and Al.

[0048] In a specific embodiment, in step (1), graphene oxide may be first dispersed in water to obtain a graphene oxide dispersion, and then alginate and the graphene oxide dispersion are mixed to obtain a mixed dispersion.

[0049] In the present invention, due to the addition of alginate, the viscosity of the material obtained by mixing alginate and graphene oxide dispersion increases, thereby avoiding the agglomeration of graphene oxide caused by the addition of alginate. In step (1), ultrasonic mixing is used to evenly disperse the material obtained by mixing graphene oxide and alginate, and the graphene oxide flakes are completely peeled off.

[0050] In a preferred embodiment, in order to better disperse graphene oxide, the power of ultrasonic mixing is 100-500 W, preferably 200-400 W, and the time of ultrasonic mixing is 10-120 min, preferably 20-50 min.

[0051] In a specific embodiment, in step (1), the solubility of alginate in water is increased by heating, so that the alginate is completely dissolved, while preventing the agglomeration of graphene oxide. Preferably, the heating temperature is 60-100° C. In the present invention, the heating time is not limited, and it only needs to be heated until the added alginate is completely dissolved, for example, it can be 3-5 hours.

[0052] In a specific embodiment, the alginate may be a commercially available alginate product commonly found in the art, for example, sodium alginate and / or potassium alginate.

[0053] In the present invention, alginate is added to the graphene oxide dispersion to improve the viscosity and strength of the mixed dispersion, thereby preventing deformation due to too low strength during the subsequent preparation of graphene oxide hydrogel fibers, thereby affecting the morphology and specific surface area of ​​the obtained composite fibers; at the same time, thanks to the addition of alginate, the strength performance of the prepared gas-sensitive material 2 is increased, and it is not easy to deform during the application process.

[0054] In a preferred embodiment, in the mixed dispersion, the mass concentration of the alginate is 0.01-5%, preferably 1-3%. Specifically, the mass concentration of the alginate can be 1%, 1.5%, 2%, 2.5% or 3%.

[0055] In a preferred embodiment, in the mixed dispersion, the concentration of the graphene oxide is 1-15 mg / mL, preferably 3-10 mg / mL. Specifically, the concentration of the graphene oxide can be 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL or 8 mg / mL.

[0056] In the present invention, in step (2), the mixed dispersion is mixed with a solution containing calcium ions for cross-linking, and the calcium ions in the solution react with the negative ions on the graphene oxide and the alginate to perform physical cross-linking, thereby combining the graphene oxide and the alginate to prepare graphene oxide hydrogel fibers.

[0057] In a preferred embodiment, the mass concentration of calcium ions in the solution containing calcium ions is 1-10%. When the concentration of calcium ions in the solution containing calcium ions is too low, the strength of the prepared graphene oxide hydrogel fiber will be too low. However, when the concentration of calcium ions is too high, the residual calcium-containing substances in the prepared graphene oxide hydrogel fiber will be too much, thereby affecting the structure and performance of the graphene-metal oxide composite fiber prepared subsequently. Specifically, the mass concentration of calcium ions in the solution containing calcium ions can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0058] In a specific embodiment, the solution containing calcium ions can be a calcium chloride solution, a calcium nitrate solution or a calcium sulfate solution.

[0059] In a preferred embodiment, in step (2), in order to ensure the morphology of the obtained graphene oxide hydrogel fiber, a microinjection pump can be used to inject the mixed dispersion into a solution containing calcium ions to form uniform graphene oxide hydrogel fibers. Specifically, the mixed dispersion can be added to a microinjection pump, and the flow rate of the microinjection pump is controlled so that the mixed dispersion falls evenly into the solution containing calcium ions for cross-linking.

[0060] In a specific embodiment, the flow rate of the microinjection pump is controlled to be 0.05-0.15 mL / min, preferably 0.1-0.15 mL / min.

[0061] In the present invention, the graphene oxide hydrogel fiber is immersed in a metal salt solution and then calcined to combine the metal oxide with the one-dimensional graphene fiber. In the present invention, when the graphene oxide hydrogel fiber is immersed in the metal salt solution, the volume of the metal salt solution used is not limited, and it is only necessary to ensure that the graphene oxide hydrogel fiber is completely immersed in the metal salt solution. The temperature during immersion is also not limited, for example, it can be room temperature 25°C. Preferably, the immersion time can be 10-15h.

[0062] In a specific embodiment, the metal salt is selected from one or more of salts of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg and Al.

[0063] In a preferred embodiment, the metal salt is selected from one or more of Zn, Cu, Co, Fe and Mn.

[0064] In the present invention, after the graphene oxide hydrogel fiber is prepared in step (2), solid-liquid separation is performed, and the graphene oxide hydrogel fiber is taken out and directly immersed in a metal salt solution without drying. When the graphene oxide hydrogel fiber is dried and then immersed in a metal salt solution, it will lead to problems such as low subsequent metal oxide loading.

[0065] In a preferred embodiment, in order to allow the graphene oxide hydrogel fiber to be more fully immersed in the metal salt solution in step (3), the graphene oxide hydrogel fiber can be wound on a roller and immersed in the metal salt solution.

[0066] In a preferred embodiment, in order to further improve the performance of the prepared graphene-metal oxide composite fiber, the weight ratio of graphene oxide to alginate is 1:0.8-10:5-50, preferably 1:1-5:6-30.

[0067] In a preferred embodiment, the concentration of the metal salt in the metal salt solution is 0.05-0.2 mol / L. Specifically, the concentration of the metal salt may be 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.15 mol / L or 0.2 mol / L.

[0068] In the present invention, sodium alginate and graphene oxide are combined to form graphene oxide hydrogel fibers. When the graphene oxide hydrogel fibers are immersed in a metal salt solution, the adsorption amount of the metal salt is increased, and the adsorbed metal salt is more evenly distributed on the fiber surface. The composite fiber finally obtained has higher strength and better performance.

[0069] In the present invention, the soaked material is sintered to remove the sodium alginate in the material, and the graphene oxide can also be reduced to further improve its conductivity and electrical properties, while also obtaining a metal oxide structure with a more stable crystal form. When the sintering temperature is too high, the metal oxide and graphene will undergo a carbon thermal reaction, and the graphene will react to generate CO 2 , resulting in a reduction in the carbon content in the final product and more carbon defects, which is not conducive to improving the performance of the graphene-metal oxide composite fiber. When the sintering temperature is too low, the content of the metal oxide will be too low.

[0070] In a preferred embodiment, in order to further improve the performance of the graphene-metal oxide composite fiber, the sintering temperature is controlled to be 200-700° C., preferably 300-600° C.; and the sintering time is 1-4 hours.

[0071] In a specific embodiment, in step (3), the sintering atmosphere is an inert atmosphere, which can be a nitrogen atmosphere, an argon atmosphere or an argon atmosphere.

[0072] The present invention further provides a method for detecting the concentration of hydrogen sulfide in gas, the method comprising: applying a working voltage to the hydrogen sulfide gas sensor, and then placing the sensor in a gas containing hydrogen sulfide for detection.

[0073] In the present invention, when the hydrogen sulfide gas sensor monitors the concentration of toxic gas, it is not necessary to heat the gas-sensitive material 2 with an external heating component in order to start the operation of the hydrogen sulfide gas sensor. The gas-sensitive material 2 can be heated by adjusting the resistance of the gas-sensitive material and the applied measurement voltage and using the current provided by the measurement circuit. Moreover, since the heating is directly generated by the gas-sensitive material 2 itself, no heat conduction is required in the middle, which can greatly reduce heat dissipation, and after removing the external heating circuit, energy consumption can be further reduced. In addition, thanks to the hollow design of the substrate in the hydrogen sulfide gas sensor, the thermal diffusion of the gas-sensitive material is further reduced, further saving the energy consumption of the entire hydrogen sulfide gas sensor, and truly realizing low-energy monitoring.

[0074] In the present invention, the working voltage is 0.1-40 V, preferably 0.5-35 V, and more preferably 1-30 V. The working voltage refers to the measured voltage of the hydrogen sulfide gas sensor during monitoring. When the applied voltage is less than the minimum value of the defined working voltage range, the temperature of the gas-sensitive material will be too low, and the hydrogen sulfide gas sensor will not be able to start monitoring; when the applied voltage is greater than the maximum value of the defined working voltage, the voltage of the hydrogen sulfide gas sensor will be too high and a fault will occur.

[0075] In the present invention, since the types of metal oxides loaded in the gas-sensitive material 2 are different, when the hydrogen sulfide gas sensor is used for monitoring, the working voltage of the hydrogen sulfide gas sensor will be adjusted accordingly according to the type of metal oxide selected, but the adjusted working voltage still needs to fall within the working voltage range specified by the present invention.

[0076] In a specific embodiment, when the metal oxide in the gas-sensitive material 2 is selected from one or more of Zn, Cu, Co, Fe and Mn, the operating voltage is 1-30V.

[0077] In the present invention, the concentration of hydrogen sulfide in the gas containing hydrogen sulfide is 0.5-50 ppm.

[0078] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0079] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0080] Example 1

[0081] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely exfoliate the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 300 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 1%).

[0082] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 mL / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0083] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of zinc nitrate aqueous solution (the concentration of zinc nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and zinc nitrate is 1:2:26.152, and the weight of zinc nitrate is calculated as zinc element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then, the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 500°C, and the sintering time is 2 hours. After sintering, the gas-sensitive material graphene-ZnO composite fiber is obtained. After thermal gravimetric detection, it is known that the ZnO content in the gas-sensitive material is 3.8wt%, and the specific surface area is 142.1m 2 / g;

[0084] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-ZnO composite fiber hydrogen sulfide gas sensor.

[0085] Example 2

[0086] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.2 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely exfoliate the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 200 W and the ultrasonic time was 40 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 2%).

[0087] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 mL / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0088] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of cobalt nitrate aqueous solution (the concentration of cobalt nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and cobalt nitrate is 1:4:23.6, and the weight of cobalt nitrate is calculated as cobalt element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 600°C, the sintering time is 2 hours, and after sintering, the gas-sensitive material graphene-Co is obtained. 3 O 4 Composite fiber. After thermal gravimetric testing, it was found that Co 3 O 4 The content is 2.7wt%, and the specific surface area is 136.5m2 / g;

[0089] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-Co 3 O 4 Composite fiber hydrogen sulfide gas sensor.

[0090] Example 3

[0091] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion, so that the graphene oxide sheets were completely peeled off and evenly dispersed in water, the ultrasonic power was 350 W, and the ultrasonic time was 35 min; then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 1%);

[0092] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 mL / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0093] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of ferric nitrate aqueous solution (the concentration of ferric nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and ferric nitrate is 1:2:22.32, and the weight of ferric nitrate is calculated as iron element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then, the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 400°C, and the sintering time is 2 hours. After sintering, the gas-sensitive material graphene-Fe 2 O 3 Composite fiber. Thermogravimetric test shows that Fe in gas-sensitive materials 2 O 3 The content is 2.9wt%, and the specific surface area is 129.3m 2 / g;

[0094] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-Fe 2 O 3 Composite fiber hydrogen sulfide gas sensor.

[0095] Example 4

[0096] (1) 100 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely exfoliate the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 300 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 10 mg / mL and the mass concentration of sodium alginate was 0.5%).

[0097] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 mL / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0098] (3) The graphene oxide hydrogel fiber is immersed in a mixed solution of 200 mL of an aqueous solution of ferric nitrate and an aqueous solution of cobalt nitrate (the concentrations of ferric nitrate and cobalt nitrate are both 0.2 mol / L, the molar ratio of ferric nitrate to cobalt nitrate is 10:1, and the total weight ratio of graphene oxide, sodium alginate, ferric nitrate and cobalt nitrate is 1:1:22.68, where the total weight of ferric nitrate and cobalt nitrate is calculated as iron and cobalt elements) at a uniform speed, and then wound onto a roller and soaked for 12 hours. The soaked graphene oxide hydrogel fiber is then dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 550°C, the sintering time is 2 hours, and after sintering, the gas-sensitive material graphene-Fe 2 O 3 / Co 3 O 4 Composite fiber. After thermal gravimetric testing, it was found that Fe 2 O 3 and Co 3 O 4 The total content is 3.1wt%, and the specific surface area is 96.9m 2 / g;

[0099] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-Fe 2 O 3 / Co 3 O 4 Composite fiber hydrogen sulfide gas sensor.

[0100] Example 5

[0101] (1) 100 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely exfoliate the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 400 W and the ultrasonic time was 25 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 10 mg / mL and the mass concentration of sodium alginate was 1%).

[0102] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 mL / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0103] (3) The graphene oxide hydrogel fiber is immersed in a mixed solution of 200 mL of an aqueous solution of iron nitrate and an aqueous solution of copper nitrate at a uniform speed (the concentrations of iron nitrate and copper nitrate are both 0.06 mol / L, the molar ratio of iron nitrate to copper nitrate is 1:1, and the total weight ratio of graphene oxide, sodium alginate, and iron nitrate to copper nitrate is 1:1:7.163, where the total weight of iron nitrate and copper nitrate is calculated as iron and copper elements), and then wound onto a roller and immersed for 12 hours. The immersed graphene oxide hydrogel fiber is then dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 600°C, the sintering time is 2 hours, and after sintering, the gas-sensitive material graphene-Fe 2 O 3 / CuO composite fiber, through the thermal gravimetric test, it can be seen that Fe in the gas-sensitive material 2 O 3 The total content of CuO is 3.5wt%, and the specific surface area is 93.4m 2 / g;

[0104] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-Fe 2 O 3 / CuO composite fiber hydrogen sulfide gas sensor.

[0105] Example 6

[0106] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely peel off the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 400 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 1%).

[0107] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 mL / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0108] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of zinc nitrate aqueous solution (the concentration of zinc nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and zinc nitrate is 1:2:26.152, and the weight of zinc nitrate is calculated as zinc element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then, the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 700°C, and the sintering time is 2 hours. After sintering, the gas-sensitive material graphene-ZnO composite fiber is obtained. After thermal gravimetric detection, it is known that the ZnO content in the gas-sensitive material is 3.4wt%, and the specific surface area is 103.2m 2 / g;

[0109] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-ZnO composite fiber hydrogen sulfide gas sensor.

[0110] Example 7

[0111] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely peel off the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 400 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 1%).

[0112] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 ml / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0113] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of zinc nitrate aqueous solution (the concentration of zinc nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and zinc nitrate is 1:2:26.152, and the weight of zinc nitrate is calculated as zinc element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then, the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 650°C, and the sintering time is 2 hours. After sintering, the gas-sensitive material graphene-ZnO composite fiber is obtained. After thermal gravimetric detection, it is known that the ZnO content in the gas-sensitive material is 3.1wt%, and the specific surface area is 111.6m 2 / g;

[0114] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-ZnO composite fiber hydrogen sulfide gas sensor.

[0115] Example 8

[0116] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely peel off the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 400 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 1%).

[0117] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 ml / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0118] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of zinc nitrate aqueous solution (the concentration of zinc nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and zinc nitrate is 1:2:26.152, and the weight of zinc nitrate is calculated as zinc element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then, the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 250°C, and the sintering time is 2 hours. After sintering, the gas-sensitive material graphene-ZnO composite fiber is obtained. After thermal gravimetric detection, it is known that the ZnO content in the gas-sensitive material is 2.6wt%, and the specific surface area is 110.4m 2 / g;

[0119] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-ZnO composite fiber hydrogen sulfide gas sensor.

[0120] Example 9

[0121] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 350 mg of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely exfoliate the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 300 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 3.3%).

[0122] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 ml / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0123] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of zinc nitrate aqueous solution (the concentration of zinc nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and zinc nitrate is 1:7:26.152, and the weight of zinc nitrate is calculated as zinc element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then, the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 500°C, and the sintering time is 2 hours. After sintering, the gas-sensitive material graphene-ZnO composite fiber is obtained. After thermal gravimetric detection, it is known that the ZnO content in the gas-sensitive material is 4.2wt%, and the specific surface area is 139.8m 2 / g;

[0124] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-ZnO composite fiber hydrogen sulfide gas sensor.

[0125] Example 10

[0126] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 40 mg of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely exfoliate the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 300 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 0.4%).

[0127] (2) adding the mixed dispersion into a microinjection pump, controlling the flow rate of the microinjection pump to 0.1 ml / min, and uniformly injecting the mixed dispersion into a calcium chloride aqueous solution (the mass concentration of calcium chloride is 5%) to form graphene oxide hydrogel fibers;

[0128] (3) The graphene oxide hydrogel fiber is immersed in 200 mL of zinc nitrate aqueous solution (the concentration of zinc nitrate is 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and zinc nitrate is 1:0.8:26.152, and the weight of zinc nitrate is calculated as zinc element) at a uniform speed, and then wound on a roller and soaked for 12 hours. Then, the soaked graphene oxide hydrogel fiber is dried in an oven at 80°C for 24 hours, and then placed in a tubular furnace for sintering in a nitrogen atmosphere; the sintering temperature is 500°C, and the sintering time is 2 hours. After sintering, the gas-sensitive material graphene-ZnO composite fiber is obtained. After thermal gravimetric detection, it is known that the ZnO content in the gas-sensitive material is 1.8wt%, and the specific surface area is 108.5m 2 / g;

[0129] (4) Connecting the two ends of the gas-sensitive material 2 to the gold electrodes 3 on the MEMS substrate 1 through the conductive silver glue 4 to obtain a one-dimensional graphene-ZnO composite fiber hydrogen sulfide gas sensor.

[0130] Comparative Example 1

[0131] The method of Example 1 was followed, except that the zinc nitrate aqueous solution was replaced with a larger volume of nano ZnO dispersion, wherein the weight of the nano ZnO was equal to the weight of the zinc nitrate. Thermogravimetric test showed that the ZnO content in the obtained gas-sensitive material was 0.046 wt % and the specific surface area was 28.3 m 2 / g; a hydrogen sulfide gas sensor is prepared by using the gas-sensitive material.

[0132] Comparative Example 2

[0133] The method of Example 1 is followed, except that the gas-sensitive material prepared in Example 1 is ground into powder, which is then coated on the surface of a flat ceramic tube substrate to obtain a hydrogen sulfide gas sensor.

[0134] Comparative Example 3

[0135] The method of Example 1 is used for implementation, except that the gas-sensitive material is laid flat on a substrate ceramic tube (with a flat surface and no cavity) to obtain a hydrogen sulfide gas sensor.

[0136] Comparative Example 4

[0137] The method of Example 1 was followed, except that the content of ZnO in the gas-sensitive material was 0.028 wt %, and the specific surface area was 19.2 m 2 / g, and the gas-sensitive material is in powder form and does not have a fiber structure;

[0138] The gas-sensitive material is prepared by the following method:

[0139] (1) 50 mg of graphene oxide was dispersed in 10 mL of deionized water to obtain a graphene oxide dispersion, and then 0.1 g of sodium alginate was added to the graphene oxide dispersion for ultrasonic dispersion to completely peel off the graphene oxide sheets and evenly disperse them in water. The ultrasonic power was 400 W and the ultrasonic time was 30 min. The mixture was then heated at 70° C. for 4 h to obtain a mixed dispersion (wherein the concentration of graphene oxide was 5 mg / mL and the mass concentration of sodium alginate was 1%).

[0140] (2) The mixed dispersion was mixed evenly with 200 mL of an aqueous zinc nitrate solution (the concentration of zinc nitrate was 0.1 mol / L, the weight ratio of graphene oxide, sodium alginate and zinc nitrate was 1:2:26.152, and the weight of zinc nitrate was calculated as zinc element) and allowed to stand for 12 h. The obtained mixed solution was then added to a microinjection pump, the flow rate of the microinjection pump was controlled to be 0.1 ml / min, and the mixed solution was evenly injected into an aqueous calcium chloride solution (the mass concentration of calcium chloride was 5%). The obtained material was then sintered in a nitrogen atmosphere at a sintering temperature of 500° C. and a sintering time of 2 h.

[0141] Comparative Example 5

[0142] The method of Example 1 is used for implementation. The difference is that sodium alginate is not added in step (1). In step (2), the graphene oxide dispersion is directly injected into the calcium chloride aqueous solution to prepare the gas-sensitive material. The ZnO content in the gas-sensitive material is 0.031wt% and the specific surface area is 25.5m 2 / g; a hydrogen sulfide gas sensor is prepared by using the gas-sensitive material.

[0143] Test Case

[0144] Test Example 1

[0145] The surface morphology of the gas-sensitive materials prepared in Examples 1-3 was characterized by SEM. Figure 2-4 shown.

[0146] Figure 1 This is the surface morphology of the gas-sensitive material graphene-ZnO composite fiber prepared in Example 1. Figure 1It can be seen that the graphene surface has many wrinkles, which come from the stacking that occurs during the reduction of graphene oxide. At the same time, there are particles of about 10nm evenly distributed on the surface. These particles are nano-ZnO, and the distribution of nano-ZnO is even.

[0147] Figure 2 The gas-sensitive material graphene / Co prepared in Example 2 3 O 4 Surface morphology of composite fibers. Figure 2 It can be seen that nanoparticles with a particle size of about 10 nm are also distributed on the surface of graphene fibers. These particles are Co 3 O 4 Particles, and Co 3 O 4 The particles are evenly distributed on the surface of graphene fibers.

[0148] Figure 3 The gas-sensitive material graphene / Fe prepared in Example 3 2 O 3 Surface morphology of composite fibers. Figure 2 It can be seen that nanoparticles with a particle size of about 10 nm are also distributed on the surface of graphene fibers. These particles are Fe 2 O 3 Particles, and Fe 2 O 3 The particles are evenly distributed on the surface of graphene fibers.

[0149] The surface morphology of the gas-sensitive materials prepared in the other embodiments is similar to Figure 1-3 similar.

[0150] Test Example 2

[0151] The self-heating performance and power consumption of the gas sensors prepared in Examples 1-10 and Comparative Examples 1-5 were tested;

[0152] Test method: Place the hydrogen sulfide gas sensor in a sealed cavity, apply different working voltages to the hydrogen sulfide gas sensor through the power supply meter, measure the resistance of the gas sensor, and use the formula P = U 2 / R is used to obtain the power consumption of the gas sensor. At the same time, an infrared thermometer is used to measure the temperature of the gas-sensitive material in the hydrogen sulfide gas sensor under different working voltages. The results are shown in Table 1.

[0153] Table 1

[0154] Example No. Heating to 100℃ Power consumption (W) Heating to 200℃ Power consumption (W) Example 1 0.011 0.030 Example 2 0.028 0.117 Example 3 0.057 0.224 Example 4 0.048 0.267 Example 5 0.059 0.231 Example 6 0.057 0.273 Example 7 0.062 0.281 Example 8 0.061 0.293 Example 9 0.073 0.205 Example 10 0.051 0.254 Comparative Example 1 0.423 0.769 Comparative Example 2 0.592 1.146 Comparative Example 3 0.544 1.098 Comparative Example 4 0.843 1.576 Comparative Example 5 0.373 0.658

[0155] It can be seen from the data in Table 1 that the hydrogen sulfide gas sensor of the present invention can be self-heated, and the power consumption required to reach the target heating temperature is lower.

[0156] Test Example 3

[0157] Response values ​​of the hydrogen sulfide gas sensors prepared in Examples 1-10 and Comparative Examples 1-5 to hydrogen sulfide gas;

[0158] Response value test method: put the hydrogen sulfide gas sensor into a closed cavity, apply working voltage to the hydrogen sulfide gas sensor, then introduce hydrogen sulfide gas (hydrogen sulfide concentration is 0.5-50ppm), and measure its response value to hydrogen sulfide at different hydrogen sulfide concentrations.

[0159] During the test, the response value of the hydrogen sulfide gas sensor S (Sensitivity) = (R x -R 0 ) / R 0 , where R 0 is the resistance value of the hydrogen sulfide gas sensor in the air, R x is the resistance value of the hydrogen sulfide gas sensor after hydrogen sulfide gas is introduced; the response time of the hydrogen sulfide gas sensor is the time when the resistance value change is 90% of the total change after hydrogen sulfide gas is introduced; the recovery time of the hydrogen sulfide gas sensor is the time when the resistance value change is 90% of the total change after air is introduced. The test results are shown in Table 2.

[0160] Table 2

[0161]

[0162] It can be seen from the results in Table 2 that the hydrogen sulfide gas sensor of the present invention has a high response value to hydrogen sulfide gas, a lower detection limit, and a shorter response time and recovery time.

[0163] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A hydrogen sulfide gas sensor, It is characterized in that The hydrogen sulfide gas sensor comprises a substrate (1) and a gas-sensitive material (2); The substrate (1) is provided with a cavity, the gas-sensitive material (2) is located above the cavity, and two ends of the gas-sensitive material (2) are connected to gold electrodes (3) on the substrate (1); The gas-sensitive material (2) comprises graphene fibers and metal oxides supported on the graphene fibers; The metal oxide is selected from one or more of the oxides of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg and Al; The specific surface area of ​​the gas-sensitive material (2) is 80-150 m 2 / g; Based on the total weight of the gas-sensitive material (2), the loading amount of the metal oxide is 0.05-5wt%.

2. The hydrogen sulfide gas sensor according to claim 1, It is characterized in that The substrate (1) is a MEMS chip.

3. The hydrogen sulfide gas sensor according to claim 1, It is characterized in that The gas-sensitive material (2) is connected to the gold electrode (3) via a conductive silver paste (4).

4. The hydrogen sulfide gas sensor according to claim 1 or 3, It is characterized in that The preparation method of the gas-sensitive material (2) comprises the following steps: (1) mixing alginate, graphene oxide and water to obtain a mixed dispersion; (2) mixing the mixed dispersion with a solution containing calcium ions to obtain graphene oxide hydrogel fibers; (3) soaking the graphene oxide hydrogel fiber in a metal salt solution and then sintering it; The metal salt is selected from one or more of salts of Zn, Cd, Cu, Ni, Pd, Pt, Co, Ir, Fe, Mn, Cr, Mo, W, V, Ti, Mg and Al.

5. The hydrogen sulfide gas sensor according to claim 4, It is characterized in that The weight ratio of graphene oxide, alginate and metal salt is 1:0.8-10:5-50.

6. The hydrogen sulfide gas sensor according to claim 4 or 5, It is characterized in that In the mixed dispersion, the mass concentration of the alginate is 0.01-5%; Preferably, in the mixed dispersion, the concentration of graphene oxide is 1-15 mg / mL; Preferably, the concentration of the metal salt in the metal salt solution is 0.05-0.2 mol / L.

7. The hydrogen sulfide gas sensor according to claim 4, It is characterized in that In step (2), the mixed dispersion is mixed with a solution containing calcium ions using a microinjection pump; Preferably, the flow rate of the microinjection pump is 0.05-0.15 mL / min.

8. Use of the hydrogen sulfide gas sensor according to any one of claims 1 to 7 in detecting the concentration of hydrogen sulfide gas.

9. A method for detecting the concentration of hydrogen sulfide in gas, It is characterized in that The method comprises: applying a working voltage to the hydrogen sulfide gas sensor, and then placing the sensor in a gas containing hydrogen sulfide for detection; Wherein, the operating voltage is 0.1-40V; The hydrogen sulfide gas sensor is the hydrogen sulfide gas sensor according to any one of claims 1 to 7.

10. The method for detecting the concentration of hydrogen sulfide in gas according to claim 9, It is characterized in that In the gas containing hydrogen sulfide, the concentration of hydrogen sulfide is 0.5-50 ppm.

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