Preparation method of high-sensitivity MoSe2-based gas sensitive material for detecting H2S at room temperature

Abstract

The invention relates to the technical field of gas sensors for detecting H2S at room temperature, in particular to a preparation method of a high-sensitivity MoSe2-based gas sensitive material for detecting H2S at room temperature. The high-sensitivity MoSe2-based gas sensitive material for detecting H2S at room temperature is prepared by synthesizing MoSe2 nanoflowers by adopting a hydrothermal method and uniformly loading In2O3 nanoparticles on the surfaces of the MoSe2 nanoflowers by adopting a mechanical mixing method. The preparation method is simple and convenient in process and low in cost, the MoSe2 / In2O3 composite material prepared by the method has a relatively high specific surface area, and an II-type p-n heterojunction interface formed by the composite material effectively promotes separation and migration of current carriers. The response to 0.05 ppm H2S, 0.1 ppm H2S, 0.25 ppm H2S, 0.5 ppm H2S and 1ppm H2S at room temperature (the gas response is calculated according to the formula R = (Rg-Ra) / Ra) is 1.37, 1.47, 1.85, 2.74 and 4.82 respectively, the response is far better than that of an existing pure-phase MoSe2 gas sensitive material, and the working temperature is lower than that of an In2O3 pure-phase material. The research provides an effective method for constructing a gas sensitive material with a large specific surface area and II type p-n heterojunction, and further promotes the development of a gas sensitive technology.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of room-temperature H2S gas sensors, in particular to a preparation method of a MoSe2-based gas-sensitive material for high-sensitivity room-temperature detection of H2S. BACKGROUND

[0002] During the production, processing, storage and transportation of food, hydrogen sulfide gas may be generated due to various reasons, such as microbial decomposition caused by fruit rotting and fermentation or reaction of food with certain chemical substances, etc. Long-term exposure to hydrogen sulfide gas may pose a potential threat to human health. Hydrogen sulfide (H2S) gas is a highly toxic gas, and after being inhaled by the human body, it can cause damage to multiple systems, such as stimulating the respiratory mucosa to cause cough and dyspnea, and damaging the central nervous system to cause dizziness and coma. By detecting the content of hydrogen sulfide gas, potential risks can be discovered in advance, and corresponding measures can be taken to prevent food from being contaminated and reduce the possibility of food safety accidents. According to the Industrial Enterprise Design Hygienic Standard (GBZ1-2010) and the Occupational Exposure Limits for Hazardous Factors in the Workplace Part 1: Chemical Hazardous Factors (GBZ 2.1-2019), the maximum allowable concentration of H2S in air is 10 mg / m 3 , i.e. 6.6-13.2 ppm. Therefore, it is very important and urgent to develop a low-cost, high-sensitivity H2S gas sensor material under room temperature conditions.

[0003] At present, MoSe2 is a typical representative of 2D transition metal sulfide (TMDs) materials, and has excellent physical and chemical properties, such as adjustable band gap size / type, large specific surface area, high room-temperature carrier concentration, and multiple preparation process options, etc. Therefore, MoSe2 has shown great application prospects in the design and development of gas sensing materials, and has gradually attracted the attention of scientific researchers. For example, in the document “Jha RK, et al. MoSe2 nanoflakes based chemiresistive sensors for ppb-level hydrogen sulfide gas detection. Sensors and Actuators B: Chemical, 2019, 297, 126687.”, MoSe2 nanosheets were prepared by a liquid phase exfoliation method, and detection of 0.5 ppm H2S gas at 200 DEG C was realized, with a response value of about 8.13. However, the detection temperature of this system is relatively high, and it is not suitable for the requirement of room-temperature response performance.

[0004] For example, in the document "Pan WJ, et al. Hydrogen sulfide gas sensing properties of metal organic framework-derived Fe2O3 hollow nanospheres decorated with MoSe2 nanoflowers. Sensors and Actuators: B Chemical, 2021, 344: 130221.", a metal organic framework-derived Fe2O3 hollow sphere and MoSe2 nanoflower composite material is synthesized by a hydrothermal method, and a gas sensor is prepared by a screen printing process, and a response of about 17 and 29 is obtained for 1 ppm and 5 ppm H2S gas at room temperature, respectively. However, the composite material constructs an n-n type heterojunction, and the efficiency of electron separation and transfer still needs to be improved.

[0005] According to the existing research results, although the gas sensing performance of the MoSe2-based material has made certain progress, there are still problems such as limited sensitivity, high response temperature, and single heterostructure. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art, and to solve the problems of high working temperature and low response of the existing MoSe2 gas sensitive material. In the present application, In2O3 nanoparticles are constructed on the MoSe2 nanoflower structure of the base material, a nanocomposite material with synergistic enhancement effect is constructed, and a gas sensitive material capable of detecting ppb-level H2S at room temperature is provided.

[0007] The inventive concept of the present application is as follows: the present application proposes a composite gas sensitive material based on MoSe2 / In2O3. After synthesizing MoSe2 nanoflowers by a hydrothermal method, In2O3 nanoparticles are uniformly loaded on the surface of the MoSe2 nanoflowers by a mechanical mixing method, and a high specific surface area composite structure is constructed. At the same time, a type II p-n heterojunction interface is formed between MoSe2 and In2O3, which effectively promotes the separation and migration of carriers. The synergistic effect of the above structure design and interface regulation significantly improves the detection sensitivity and response speed of the material to ppb-level H2S gas at room temperature, and the overall performance is better than that of the existing MoSe2-based gas sensitive system, which has a wide application prospect.

[0008] In order to achieve the above-mentioned purpose, the present application is implemented by adopting the following specific technical solutions,

[0009] In the first aspect of the present application, a preparation method of a MoSe2-based gas sensitive material for high-sensitivity room temperature detection of H2S is provided. The material is prepared by uniformly loading In2O3 nanoparticles on the surface of MoSe2 nanoflowers synthesized by a hydrothermal method, and the specific steps are as follows:

[0010] (1) Synthesis of MoSe2 nanoflower: Se powder was dissolved in ammonia water, and the dissolved Se powder, NaBH4, Na2MoO4·2H2O and ethanol were sequentially added to deionized water, and placed in an autoclave for heating, and high-purity MoSe2 nanoflower powder was obtained after natural cooling;

[0011] (2) Synthesis of In2O3 nanopowder: In(NO3)3·4.5H2O was dissolved in ethanol, NH3·H2O was added and stirred, and after washing with deionized water and ethanol several times, it was placed in an oven for heating and naturally cooled to obtain In2O3 nanoparticles;

[0012] (3) Synthesis of In2O3 / MoSe2 nanocomposite: MoSe2 and In2O3 were dispersed in anhydrous ethanol, the mass of In2O3 was 75wt.% of the mass of MoSe2, and were fully stirred, and were placed in a tube furnace for annealing under a flowing dry atmosphere, and finally MoSe2 / In2O3 nanocomposite was obtained.

[0013] Preferably, in the step (1), the ratio of Se powder to ammonia water is 0.5g:20mL.

[0014] Preferably, in the step (1), the ratio of Se powder, NaBH4, Na2MoO4·2H2O and ethanol is 5g:1g:6g:250mL.

[0015] Preferably, in the step (1), the heating temperature of the autoclave is 200℃, and the heating time is 48h.

[0016] Preferably, in the step (2), the ratio of In(NO3)3·4.5H2O, NH3·H2O and ethanol is 1mmol:4ml:20mL, and the NH3·H2O is 25% NH3·H2O.

[0017] Preferably, in the step (2), the heating temperature of the oven is 100℃, and the heating time is 24h.

[0018] Preferably, in the step (3), the ratio of MoSe2, In2O3 and ethanol is 1g:0.75g:10mL

[0019] Preferably, in the step (3), the stirring time is 1h, the annealing atmosphere is Ar+10% H2, the heating rate is 10℃·min -1 , the temperature is 400℃, and the holding time is 2h.

[0020] In a second aspect of the present invention, a method for detecting H2S using a MoSe2-based gas-sensitive material prepared by the method described in the first aspect is provided, comprising the following steps: dispersing MoSe2 or MoSe2 / In2O3 nanomaterials in ethanol, dropping the nanomaterials on the surface of a Pt electrode, and drying the nanomaterials. Then, a dynamic four-channel gas-sensitive test system (SD101) is used to record the response and recovery characteristics of the gas-sensitive material to the target gas. After exposing the electrode coated with the gas-sensitive material to target gases of different concentrations, the corresponding resistance R is measured at room temperature. g After reaching the peak, air was introduced and the electrode was heated to 100°C to facilitate gas desorption, and then cooled to room temperature to measure its resistance in air (R a ), the gas response is given by the formula R=(R g -R a ) / R a calculate.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] (1) The present invention adopts a hydrothermal method to prepare MoSe2 nanosheets and In2O3 nanoparticles respectively, and then prepares MoSe2 / In2O3 nanocomposites with different In2O3 loading ratios by mechanical mixing. The specific surface area of ​​the prepared MoSe2 / In2O3 nanocomposites is significantly improved. The introduction of In2O3 not only significantly increases the specific surface area of ​​the MoSe2 nanostructure, but also introduces abundant oxygen vacancies into the composite material. These oxygen vacancies can serve as active adsorption sites, releasing unpaired electrons, enhancing the adsorption and reaction ability of the material with H2S molecules, thereby improving the gas-sensitive response characteristics.

[0023] (2) In the MoSe2 / In2O3 nanocomposite prepared by the present invention, a type II p-n heterojunction interface is formed between MoSe2 and In2O3, which can effectively promote the separation and migration of carriers at the interface, improve the electron transfer efficiency, and further enhance the response sensitivity and response rate to H2S. The gas-sensitive operating temperature of the MoSe2 / In2O3 nanocomposite of the present invention is room temperature. The dynamic response values ​​of the MoSe2 / 0.75-In2O3 composite material to 0.05, 0.1, 0.25, 0.5 and 1 ppm H2S are 1.37, 1.47, 1.85, 2.74 and 4.82, respectively. The minimum detection concentration of the present invention is 0.05 ppm. Existing technologies, such as Zhao Ye's master's thesis, "Research on H2S Gas Sensors Based on Thin Film Materials," utilize mechanical exfoliation to prepare few-layer MoS2 sheets. In2O3 thin films are then deposited on the MoS2 sheets using magnetron sputtering. By optimizing the magnetron sputtering process, In2O3 films of varying thicknesses were obtained. The gas-sensing test temperature for these MoS2 / In2O3 films was 100°C, and the response to H2S from 1 ppm to 50 ppm increased from 0.05 to 0.15, with a minimum detection concentration of 0.1 ppm. The gas-sensing response and detection threshold of the present invention are superior to those of existing technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 Surface scanning electron micrographs of pure MoSe2 and the MoSe2 / In2O3 nanocomposite for highly sensitive room-temperature H2S detection described in the present invention. (a) shows the morphology of MoSe2, (b) the morphology of the MoSe2 / 0.25-In2O3 composite, (c) the morphology of the MoSe2 / 0.50-In2O3 composite, and (d) the morphology of the MoSe2 / 0.75-In2O3 composite.

[0026] Figure 2 The X-ray diffraction (XRD) patterns of pure MoSe2, pure In2O3, and the highly sensitive room-temperature detection MoSe2 / In2O3 nanomaterials described in the present invention are shown in Figure 1. (a) shows the XRD patterns of pure MoSe2 and In2O3, and (b) shows the XRD patterns of MoSe2 / In2O3 nanomaterials loaded with different In2O3 contents.

[0027] Figure 3N2 adsorption-desorption isotherms of pure phase MoSe2 and high-sensitivity room temperature detection MoSe2 / 0.75-In2O3 nanocomposite according to the present application. Wherein a is the N2 adsorption-desorption isotherm of pure phase MoSe2, b is the N2 adsorption-desorption isotherm of MoSe2 / 0.75-In2O3 composite material.

[0028] Figure 4 Gas sensing performance of MoSe2 / In2O3 nanocomposite with different In2O3 loading contents according to the present application to 1 ppm H2S.

[0029] Figure 5 Response curves of high-sensitivity room temperature detection MoSe2 / 0.75-In2O3 nanocomposite according to the present application to 0.05, 0.1, 0.25, 0.5 and 1 ppm H2S.

[0030] Figure 6 (αhv) of pure phase MoSe2, In2O3 2 -hv graph and band gap fitting curve, and valence band X-ray photoelectron spectroscopy. Wherein a and b are (αhv) of pure phase MoSe2 and In2O3 respectively 2 -hv graph and band gap fitting curve, and valence band X-ray photoelectron spectroscopy. Wherein a and b are (αhv) of pure phase MoSe2 and In2O3 respectively DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in a clear and complete manner in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0032] The specific techniques or conditions not specified in the embodiments can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. It should be noted that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0033] The detailed case is explained as follows:

[0034] Embodiment 1:

[0035] (1) Synthesis of MoSe2 nanomaterials: 0.5 g of Se powder was dissolved in 20 ml of ammonia solution and stirred for 30 min. The dissolved Se powder solution, 0.1 g of NaBH4, 0.6 g of Na2MoO4·2H2O, and 25 ml of ethanol were then added to 25 ml of deionized water and stirred continuously at room temperature for 1 h. The mixture was then transferred to an autoclave, heated at 200°C for 48 h, and allowed to cool naturally. The MoSe2 nanomaterials were then washed and dried to obtain the desired product.

[0036] (2) Preparation of gas sensor: To prepare pure MoSe2 gas sensor, 0.025g MoSe2 powder was evenly dispersed in 0.1mL ethanol, and the mixed liquid was dropped on the surface of Pt electrode. After drying, the dynamic four-channel gas sensing test system (SD101) was used to record the response and recovery characteristics of the gas-sensitive material to the target gas. After the electrode coated with the gas-sensitive material was exposed to different concentrations of the target gas, its corresponding resistance R was measured at room temperature. g After reaching the peak, air was introduced and the electrode was heated to 100°C to facilitate gas desorption, and then cooled to room temperature to measure its resistance in air (R a ), the gas response is given by the formula R=(R g -R a ) / R a calculate.

[0037] To analyze the morphology and performance of MoSe2, Figure 1 As shown in a, MoSe2 powder has a unique petal-like multilayer structure and Figure 2 The XRD characteristic curve of MoSe2 is shown, confirming the successful synthesis of MoSe2. Figure 3 a shows the N2 adsorption-desorption isotherm of MoSe2 nanoflowers, and its surface specific area is 12.30 m 2 / g. Figure 4 The response values ​​of different In2O3 loading ratios to 1ppm H2S are shown. The room temperature response value of pure MoSe2 is 1.86.

[0038] Example 2:

[0039] (1) Synthesis of MoSe2 nanoflowers: 0.5 g of Se powder was dissolved in 20 ml of ammonia solution and stirred for 30 min. The dissolved Se powder solution, 0.1 g of NaBH4, 0.6 g of Na2MoO4·2H2O, and 25 ml of ethanol were then added to 25 ml of deionized water and stirred continuously at room temperature for 1 h. The mixture was then transferred to an autoclave, heated at 200°C for 48 h, and allowed to cool naturally. The MoSe2 nanoflowers were then washed and dried to obtain the desired product.

[0040] (2) Synthesis of In2O3 nanopowder: 1 mmol In(NO3)3·4.5H2O was dissolved in 20 ml of ethanol and 4 ml of 25% NH3·H2O, and mechanically stirred until transparent. The mixture was then transferred to a 100 mL reactor and placed in an oven at 100°C. After heating for 24 hours, the mixture was naturally cooled to obtain In2O3 nanoparticles.

[0041] (3) Synthesis of MoSe2 / In2O3 nanocomposite materials: 1 g of prepared MoSe2 and 0.25 g of In2O3 nanopowder were dispersed in 10 mL of anhydrous ethanol, with the mass of In2O3 being 25 wt.% of the mass of MoSe2. The mixture was mechanically stirred for 1 h. The mixture was annealed in a flowing dry Ar + 10% H2 atmosphere at a heating rate of 10°C min-1. -1 , annealing temperature is 400℃, holding time is 2h, and MoSe2 / 0.25-In2O3 composite material is obtained.

[0042] (4) Preparation of gas sensor: 0.025g MoSe2 / 0.25-In2O3 composite material powder was evenly dispersed in 0.1mL ethanol, and the mixed liquid was dropped on the surface of the Pt electrode. After drying, the dynamic four-channel gas sensing test system (SD101) was used to record the response and recovery characteristics of the gas-sensitive material to the target gas. After the electrode coated with the gas-sensitive material was exposed to different concentrations of the target gas, its corresponding resistance R was measured at room temperature. g After reaching the peak, air was introduced and the electrode was heated to 100°C to facilitate gas desorption, and then cooled to room temperature to measure its resistance in air (R a ), the gas response is given by the formula R=(R g -R a ) / R a calculate.

[0043] Figure 1 b is the morphology of MoSe2 / 0.25-In2O3 composite material, indicating that In2O3 nanoparticles are loaded on the MoSe2 material, and Figure 2 The XRD diffraction pattern also confirmed the successful synthesis and loading of In2O3. Figure 4 The response values ​​of different In2O3 loading ratios to 1ppmH2S are shown. The room temperature response value of MoSe2 / 0.25-In2O3 is 1.03.

[0044] Example 3:

[0045] (1) Synthesis of MoSe2 nanoflowers: The method is the same as step (1) of Example 2.

[0046] (2) Synthesis of In2O3 nanopowder: The method is the same as step (2) of Example 2.

[0047] (3) Synthesis of MoSe2 / In2O3 nanocomposite materials: 1 g of prepared MoSe2 and 0.5 g of In2O3 nanopowder were dispersed in 10 mL of anhydrous ethanol, with the mass of In2O3 being 50 wt.% of the mass of MoSe2. The mixture was mechanically stirred for 1 h. The mixture was annealed in a flowing dry Ar + 10% H2 atmosphere at a heating rate of 10°C min-1. -1 The annealing temperature was 400℃ and the holding time was 2h to obtain MoSe2 / 0.50-In2O3 composite material.

[0048] (4) Preparation of gas sensor: 0.025g MoSe2 / 0.50-In2O3 composite material powder was evenly dispersed in 0.1mL ethanol, and the mixed liquid was dropped on the surface of the Pt electrode. After drying, the dynamic four-channel gas sensing test system (SD101) was used to record the response and recovery characteristics of the gas-sensitive material to the target gas. After the electrode coated with the gas-sensitive material was exposed to different concentrations of the target gas, its corresponding resistance R was measured at room temperature. g After reaching the peak, air was introduced and the electrode was heated to 100°C to facilitate gas desorption, and then cooled to room temperature to measure its resistance in air (R a ), the gas response is given by the formula R=(R g -R a ) / R a calculate.

[0049] Figure 1 c is the morphology of MoSe2 / 0.50-In2O3 composite material, indicating that In2O3 nanoparticles are loaded on the MoSe2 material, and Figure 2 The XRD pattern of b also confirms that the peak intensity of In2O3 increases with the increase of In2O3 loading content. Figure 4 The response values ​​of different In2O3 loading ratios to 1ppmH2S are shown. The room temperature response value of MoSe2 / 0.50-In2O3 is 1.12.

[0050] Embodiment 4:

[0051] (1) Synthesis of MoSe2 nanoflowers: The method is the same as step (1) of Example 2.

[0052] (2) Synthesis of In2O3 nanopowder: The method is the same as step (2) of Example 2.

[0053] (3) Synthesis of MoSe2 / In2O3 nanocomposite materials: 1 g of prepared MoSe2 and 0.75 g of In2O3 nanopowder were dispersed in 10 mL of anhydrous ethanol, with the mass of In2O3 being 75 wt.% of the mass of MoSe2. The mixture was mechanically stirred for 1 h. The mixture was annealed in a flowing dry Ar + 10% H2 atmosphere at a heating rate of 10°C min-1. -1 , annealing temperature is 400℃, holding time is 2h, and MoSe2 / 0.75-In2O3 composite material is obtained.

[0054] (4) Preparation of gas sensor: 0.025g MoSe2 / 0.75-In2O3 composite material powder was evenly dispersed in 0.1mL ethanol, and the mixed liquid was dropped on the surface of the Pt electrode. After drying, the dynamic four-channel gas sensing test system (SD101) was used to record the response and recovery characteristics of the gas-sensitive material to the target gas. After the electrode coated with the gas-sensitive material was exposed to different concentrations of the target gas, its corresponding resistance R was measured at room temperature. g After reaching the peak, air was introduced and the electrode was heated to 100°C to facilitate gas desorption, and then cooled to room temperature to measure its resistance in air (R a ), the gas response is given by the formula R=(R g -R a ) / R a calculate.

[0055] Figure 1 d is the morphology of the MoSe2 / 0.75-In2O3 composite material, indicating that In2O3 nanoparticles are loaded on the MoSe2 material, and with the increase of In2O3 content, the content of particles loaded on the surface also increases, accompanied by the increase of the peak intensity of In2O3 in the XRD diffraction pattern ( Figure 2 b).

[0056] Figure 3 b shows that the specific surface area of ​​the In2O3 / 0.75-MoSe2 composite material is 56.93 m 2 / g, higher than pure MoSe2 nanoflowers (12.30m 2 / g), indicating that the loading of In2O3 can effectively increase the specific surface area of ​​MoSe2 nanoflowers, thereby providing more active adsorption sites.

[0057] Figure 4 The response values ​​of MoSe2 / In2O3 composite materials with different In2O3 loading ratios to 1ppmH2S, among which the room temperature response value of MoSe2 / 0.75-In2O3 is 4.82.

[0058] Figure 5The results show that the dynamic response values ​​of the MoSe2 / 0.75-In2O3 composite material to 0.05, 0.1, 0.25, 0.5, and 1 ppm H2S are 1.37, 1.47, 1.85, 2.74, and 4.82, respectively. This indicates that there is a good linear relationship between the response of the MoSe2 / 0.75-In2O3 composite material and the H2S concentration, and it can make good predictions for different H2S concentrations.

[0059] Figure 6 The UV-visible absorption spectra and valence-band X-ray photoelectron spectra of MoSe2 and In2O3 are shown. Based on the UV-visible absorption spectra of pure MoSe2 and In2O3, their band gaps are calculated to be 1.54 and 2.61 eV, respectively. Transvalence-band X-ray photoelectron spectroscopy can measure the valence band edges of pure MoSe2 and In2O3, calculating their positions relative to the Fermi level to be 0.23 and 1.88 eV, respectively. Based on the work functions of the two materials, it is confirmed that p-type MoSe2 can form a typical type II heterojunction with n-type In2O3.

[0060] Example 5

[0061] Referring to the method of Example 2, MoSe2 / In2O3 nanocomposites with different In2O3 loading contents were prepared, and the gas sensing properties of each nanocomposite material to different concentrations of H2S were tested according to the method of Example 2. The results are shown in Table 1:

[0062] Table 1 Gas sensing properties of MoSe2 / In2O3 nanocomposites with different In2O3 loading contents to different concentrations of H2S

[0063] <![CDATA[In2O3负载含量]]> 0.5 (ppm) 1 (ppm) 0.10 0.48 0.84 0.25 0.67 1.03 0.30 0.75 1.09 0.50 0.87 1.12 0.75 2.74 4.82 1.00 0.91 1.04

[0064] As shown in Table 1, the response of the MoSe2 / In2O3 nanocomposite to H2S increases with increasing In2O3 loading, then decreases. The gas sensor based on the MoSe2 / 0.75–In2O3 system achieves the highest gas response. Clearly, an appropriate In2O3 loading can maximize the role of the type II heterojunction in promoting carrier separation and transport, significantly enhancing the composite's gas-sensing performance.

[0065] The above descriptions are only some typical cases of the present invention and are not intended to limit the present invention. Any modifications, changes and conversions of equivalent elements made to the above embodiments based on the essence of the process of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a MoSe2-based gas-sensitive material for highly sensitive room-temperature detection of H2S, characterized in that: The material is prepared by synthesizing MoSe2 nanoflowers by a hydrothermal method and then uniformly loading In2O3 nanoparticles on the surface of the flowers by a mechanical mixing method, specifically comprising the following steps: (1) Synthesis of MoSe2 nanoflowers: Se powder was dissolved in ammonia water, and the dissolved Se powder, NaBH4, Na2MoO4·2H2O, and ethanol were added to deionized water in sequence. The mixture was placed in an autoclave for heating and naturally cooled to obtain high-purity MoSe2 nanoflower powder. (2) Synthesis of In2O3 nanopowder: In(NO3)3·4.5H2O was dissolved in ethanol, NH3·H2O was added and stirred, and the mixture was washed several times with deionized water and ethanol. The mixture was then heated in an oven and cooled naturally to obtain In2O3 nanoparticles. (3) Synthesis of In2O3 / MoSe2 nanocomposite materials: MoSe2 and In2O3 were dispersed in anhydrous ethanol, with the mass of In2O3 being 75 wt.% of the mass of MoSe2. The mixture was fully stirred and placed in a tubular furnace for annealing under a flowing dry atmosphere to obtain a MoSe2 / In2O3 nanocomposite material.

2. The method for preparing a MoSe2-based gas-sensitive material for detecting H2S at room temperature with high sensitivity according to claim 1, wherein: In the step (1), the ratio of Se powder to ammonia water is 0.5 g:20 mL.

3. The method for preparing a MoSe2-based gas-sensitive material for detecting H2S at room temperature with high sensitivity according to claim 1, wherein: In the step (1), the ratio of Se powder, NaBH4, Na2MoO4·2H2O and ethanol is 5g:1g:6g:250mL.

4. The method for preparing a MoSe2-based gas-sensitive material for detecting H2S at room temperature with high sensitivity according to claim 1, wherein: In the step (1), the autoclave is heated to a temperature of 200° C. for 48 hours.

5. The method for preparing a MoSe2-based gas-sensitive material for detecting H2S at room temperature with high sensitivity according to claim 1, wherein: In the step (2), the ratio of In(NO3)3·4.5H2O, NH3·H2O and ethanol is 1mmol:4ml:20mL, and the NH3·H2O is 25% NH3·H2O.

6. The method for preparing a MoSe2-based gas-sensitive material for detecting H2S at room temperature with high sensitivity according to claim 1, characterized in that: In the step (2), the oven is heated to a temperature of 100° C. for 24 hours.

7. The method for preparing a MoSe2-based gas-sensitive material for detecting H2S at room temperature with high sensitivity according to claim 1, characterized in that: In the step (3), the ratio of MoSe2, In2O3 and ethanol is 1g:0.75g:10mL.

8. The method for preparing a MoSe2-based gas-sensitive material for detecting H2S at room temperature with high sensitivity according to claim 1, characterized in that: In the step (3), the stirring time is 1 hour, the annealing atmosphere is Ar + 10% H2, and the heating rate is 10°C·min -1 , temperature is 400℃, and holding time is 2h.

9. A method for detecting H2S using a MoSe2-based gas-sensitive material prepared by the method according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: dispersing MoSe2 or MoSe2 / In2O3 nanomaterials in ethanol, dropping the nanomaterials on the surface of a Pt electrode, and then drying the nanomaterials. The method uses a dynamic four-channel gas sensing test system (SD101) to record the response and recovery characteristics of the gas-sensitive material to the target gas. The electrode coated with the gas-sensitive material is exposed to target gases of different concentrations, and the corresponding resistance R is measured at room temperature. g After reaching the peak, air was introduced and the electrode was heated to 100°C to facilitate gas desorption, and then cooled to room temperature to measure its resistance in air (R a ), the gas response is given by the formula R=(R g -R a ) / R a calculate.

Images