In2o3 / mxene composite material, preparation method thereof and application in triethylamine detection

Abstract

The application discloses an In2O3 / MXene composite material, a preparation method thereof and a triethylamine detection application, wherein the In2O3 / MXene composite material is composed of rod-shaped nanoparticulates under single-layer sheet-shaped wrapping of p-type semiconductor metal two-dimensional material MXene and n-type semiconductor In2O3, and small and dense voids are distributed on the surface of the rod-shaped nanoparticulates. The In2O3 / MXene composite material disclosed by the application is in a rod-shaped nanoparticulate structure under single-layer sheet-shaped wrapping, small and dense voids exist on the surface, and abundant active sites are provided for oxygen adhesion, so that a greater current response can be obtained, the gas sensing performance is better than that of pure indium oxide, and the detection performance on triethylamine gas is enhanced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of indium oxide-based composite material preparation, and particularly relates to an In2O3 / MXene composite material, a preparation method thereof, and a triethylamine detection application. BACKGROUND

[0002] In various chemical processes using triethylamine as an industrial raw material, systems related to triethylamine production, storage, and transportation, real-time detection of triethylamine leakage and timely alarm are very important to support the efficient application of safety technology.

[0003] Metal oxide semiconductor-based sensors have wide application prospects, especially In2O3, which has good response to triethylamine gas. However, the low conductivity of In2O3 limits its detection performance. The detection performance of In2O3 can be improved by compounding with a specific two-dimensional material, and the detection performance of triethylamine gas can be improved. MXene is a p-type semiconductor, and single-layer MXene has high conductivity similar to metal, high electron mobility, stable chemical properties, high specific surface area, and other advantages, and has become one of the most promising materials in the fields of sensors, catalysis, energy storage, etc. SUMMARY

[0004] The application aims to provide an In2O3 / MXene composite material, a preparation method thereof, and a triethylamine detection application, which can effectively improve the gas sensitivity of indium oxide and enhance the detection performance of triethylamine gas.

[0005] The technical scheme is as follows: The In2O3 / MXene composite material comprises rod-shaped nanometer particles wrapped by a single-layer sheet-shaped p-type semiconductor metal two-dimensional material MXene and n-type semiconductor In2O3, and the surface of the rod-shaped nanometer particles is distributed with voids for providing rich active sites for oxygen adhesion.

[0006] As a further limited scheme of the composite material of the application, the diameter of the rod-shaped nanometer particles is 30-70 nm.

[0007] The application further provides a preparation method of the In2O3 / MXene composite material for preparing the In2O3 / MXene composite material, and the specific steps are as follows:

[0008] Step 1: preparing single-layer sheet-shaped MXene;

[0009] Step 2: mixing indium nitrate hydrate and MXene with N-N-dimethylformamide respectively, stirring uniformly to obtain two mixed solutions, and then adding the two mixed solutions into polyvinylpyrrolidone and stirring and mixing;

[0010] Step 3, the mixed solution is subjected to electrostatic spinning treatment to obtain an In2O3 / MXene composite material precursor;

[0011] Step 4, the In2O3 / MXene composite material precursor is subjected to annealing treatment to obtain single-layer sheet-wrapped rod-shaped nanoparticles, that is, the In2O3 / MXene composite material.

[0012] As a further limited scheme of the preparation method of the application, in step 1, the specific steps for preparing the single-layer sheet-shaped MXene are as follows:

[0013] Step 1.1, hydrochloric acid and lithium fluoride are mixed in a polyethylene beaker and then heated and stirred in a magnetic stirrer;

[0014] Step 1.2, aluminum titanium carbide is added for etching, and then centrifugation, ultrasonic treatment and freeze-drying treatment are performed to obtain the single-layer sheet-shaped MXene.

[0015] As a further limited scheme of the preparation method of the application, in step 1.1, the mass ratio of hydrochloric acid to lithium fluoride is 1:10-1:20, the reaction time for heating and stirring in the magnetic stirrer is 5-15 minutes, the stirring speed range is 300 r / min-400 r / min, and the oil bath temperature range is 38℃-42℃.

[0016] As a further limited scheme of the preparation method of the application, in step 1.2, when the aluminum titanium carbide is added, the mass ratio of aluminum titanium carbide to hydrochloric acid is 1:20-1:30, and the reaction time for etching ranges from 36 to 48 hours.

[0017] As a further limited scheme of the preparation method of the application, in step 2, the mass ratio of indium nitrate hydrate to MXene ranges from 10:1 to 200:1, the mass ratio of indium nitrate hydrate to N-N-dimethylformamide is 1:15, the mass ratio of MXene to N-N-dimethylformamide ranges from 1:150 to 1:3000, and the stirring time for mixing with N-N-dimethylformamide is 5-15 minutes.

[0018] As a further limited scheme of the preparation method of the application, in step 2, after the two mixed solutions are added to polyvinylpyrrolidone, the mass ratio of indium nitrate hydrate to polyvinylpyrrolidone is 1:0.36, the stirring time ranges from 12 hours to 18 hours, and the stirring speed range is 500 r / min-600 r / min.

[0019] As a further limited scheme of the preparation method of the application, in step 3, when the electrostatic spinning treatment is performed, the voltage applied to the needle is 16kV-18kV, the sample injection rate is 0.3ml / h-1ml / h, the collector rotation speed is 100r / min, and the humidity control is 15%rh-20%rh; in step 4, when the annealing treatment is performed, the annealing heating rate is 5℃ / min, the highest annealing temperature is 400℃-700℃, and the annealing time is 2.5h-3.5h, and then the temperature is naturally reduced to room temperature.

[0020] The application further provides an In2O3 / MXene composite material for detecting triethylamine.

[0021] Compared with the prior art, the application has the beneficial effects that: the In2O3 / MXene composite material disclosed in the application has a single-layer sheet-shaped wrapped rod-shaped nanoparticle structure, small and dense voids exist on the surface, which provide abundant active sites for the attachment of oxygen, so that a greater current response can be obtained, the gas sensing performance is better than that of pure indium oxide, and the detection performance of triethylamine gas is enhanced; the preparation method of the application is simple, the material performance is excellent, and the cost is low, and the application has great application potential for real-time detection and timely alarm of triethylamine leakage in systems that need various chemical processes using triethylamine as an industrial raw material, and that are related to triethylamine production, storage and transportation. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The scanning electron microscope image of In2O3 / MXene is shown in the application;

[0023] Figure 2 The transmission electron microscope image of In2O3 / MXene is shown in the application;

[0024] Figure 3 The element mapping image of In2O3 / MXene is shown in the application; wherein, a is a high-angle annular dark-field image, b is a C element, c is an N element, d is an O element, e is a Ti element, and f is an In element;

[0025] Figure 4 The scanning electron microscope image of MXene is shown in the application;

[0026] Figure 5 Fig. a in the figure is a response-recovery curve of a pure In2O3-based sensor at 1V exposed to 1ppm triethylamine; Fig. b is a response-recovery curve of an In2O3 / MXene-based sensor at 1V exposed to 1ppm triethylamine in the application example;

[0027] Figure 6The response-recovery curve of the In2O3 / MXene-based sensor for the example of the present application exposed to different concentrations of triethylamine environment at 1V;

[0028] Figure 7 The concentration response fitting curve of the In2O3 / MXene-based sensor for the example of the present application exposed to different concentrations of triethylamine environment at 1V;

[0029] Figure 8 The sensor sensitivity change curve of the In2O3 / MXene-based sensor for the example of the present application continuously exposed to 1ppm triethylamine environment at 1V;

[0030] Figure 9 The sensitivity change curve of the In2O3 / MXene-based sensor for the example of the present application exposed to 1ppm triethylamine in different humidity environments at 1V. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings, but the protection scope of the present application is not limited to the described embodiments.

[0032] As shown in Figure 1 The In2O3 / MXene composite material disclosed by the present application is a rod-shaped nanoparticle under single-layer sheet-shaped wrapping composed of p-type semiconductor metal two-dimensional material MXene coating n-type semiconductor In2O3, and there are small and dense voids distributed on the surface of the rod-shaped nanoparticle, which are used to provide abundant active sites for the attachment of oxygen.

[0033] As a further limited scheme of the composite material of the present application, the diameter of the rod-shaped nanoparticle is 30nm-70nm, and the general particle diameter is about 50nm.

[0034] The present application also provides a preparation method of In2O3 / MXene composite material, which is used for preparing In2O3 / MXene composite material, and the specific steps are as follows:

[0035] Step 1, preparing single-layer sheet-shaped MXene;

[0036] Step 2, mixing indium nitrate hydrate (In(NO3)3·nH2O) and MXene with N-N-dimethylformamide (DMF) respectively, stirring uniformly to obtain two mixed solutions, then adding the two mixed solutions into polyvinylpyrrolidone (PVP), and stirring again;

[0037] Step 3, electrospinning the stirred solution to obtain In2O3 / MXene composite material precursor;

[0038] Step 4, annealing the In2O3 / MXene composite material precursor to obtain single-layer sheet-wrapped rod-shaped nanoparticles, i.e. the In2O3 / MXene composite material.

[0039] As a further limited scheme of the preparation method of the application, in step 1, the specific steps for preparing single-layer sheet-shaped MXene are as follows:

[0040] Step 1.1, mixing hydrochloric acid (HCl) and lithium fluoride (LiF) in a polyethylene beaker, and then placing it in a magnetic stirrer for heating and stirring;

[0041] Step 1.2, adding aluminum titanium carbide (Ti3AlC2) for etching, and then performing centrifugation, ultrasonic treatment and freeze-drying treatment to obtain single-layer sheet-shaped MXene.

[0042] As a further limited scheme of the preparation method of the application, in step 1.1, the mass ratio of hydrochloric acid to lithium fluoride is 1:10 to 1:20, preferably 1:15, the reaction time for heating and stirring in the magnetic stirrer is 5 to 15 minutes, preferably 10 minutes, the stirring speed is in the range of 300 r / min to 400 r / min, and the oil bath temperature is in the range of 38°C to 42°C.

[0043] As a further limited scheme of the preparation method of the application, in step 1.2, when adding aluminum titanium carbide, the mass ratio of aluminum titanium carbide to hydrochloric acid is 1:20 to 1:30, preferably 1:25, and the reaction time for etching is in the range of 36 to 48 hours, preferably 36 hours.

[0044] As a further limited scheme of the preparation method of the application, in step 1.2, the specific steps for centrifugation, ultrasonic treatment and freeze-drying treatment are as follows:

[0045] First, collect the bottom sediment and wash it with 1M dilute hydrochloric acid by centrifugation for 3 to 5 times at a speed of 3500 r / min, and then wash it with deionized water by centrifugation for 3 to 5 times at a speed of 3500 r / min until the pH is about 6, and collect the sediment for ultrasonic treatment;

[0046] Then, during the ultrasonic treatment, inert gas is introduced for protection, and the ultrasonic treatment is carried out in an ice water bath for a total of 2 hours;

[0047] Finally, the upper liquid is collected and freeze-dried, with a freezing time of 24 hours and a drying time of 48 to 60 hours.

[0048] As a further limited scheme of the preparation method of the application, in step 2, the mass ratio of indium nitrate hydrate to MXene ranges from 10:1 to 200:1, the mass ratio of indium nitrate hydrate to N-N-dimethylformamide is 1:15, the mass ratio of MXene to N-N-dimethylformamide ranges from 1:150 to 1:3000, and the mixing time of stirring with N-N-dimethylformamide is 5-15 minutes, preferably 10 minutes.

[0049] As a further limited scheme of the preparation method of the application, in step 2, after the two mixed solutions are added to polyvinylpyrrolidone, the mass ratio of indium nitrate hydrate to polyvinylpyrrolidone is 1:0.36, the stirring time ranges from 12h to 18h, and the stirring speed ranges from 500r / min to 600r / min.

[0050] As a further limited scheme of the preparation method of the application, in step 3, when performing electrospinning treatment, the voltage applied to the needle is 16kV-18kV, the sample injection rate is 0.3ml / h-1ml / h, the collector speed is 100r / min, and the humidity control is 15%rh-20%rh; in step 4, when performing annealing treatment, the annealing heating rate is 5℃ / min, the highest annealing temperature is 400℃-700℃, the annealing time is 2.5h-3.5h, and the preferred time is 3h, and then naturally cooled to room temperature.

[0051] The application also provides a triethylamine detection application of the In2O3 / MXene composite material, for example, constructing an In2O3 / MXene-based sensor for detecting triethylamine gas, and the specific construction steps are as follows:

[0052] First, the Au interdigital electrode is pretreated, the Au interdigital electrode is polished with magnesium oxide powder with particle sizes of 0.4μm and 0.02μm respectively, the polished electrode is first placed in anhydrous ethanol for ultrasonic cleaning for 6-10 minutes to remove organic dirt, then placed in ultrapure water for ultrasonic cleaning for 10-15 minutes to remove residual ethanol and magnesium oxide particles, and then the electrode surface is dried with high-purity nitrogen;

[0053] Then, 3-5mg of In2O3 / MXene composite material is weighed, mixed with 20μm-40μm of anhydrous ethanol and ultrasonically mixed uniformly to obtain a uniform In2O3 / MXene anhydrous ethanol composite dispersion liquid, 3-5μL of the In2O3 / MXene anhydrous ethanol composite dispersion liquid is removed with a pipette gun and dropped onto the surface of the Au interdigital electrode, and the modification is performed 3-5 times, and the In2O3 / MXene-based sensor is obtained after heating and drying on a heating table for 2-3h;

[0054] Then, the In2O3 / MXene-based sensor was continuously exposed to different concentrations of triethylamine, and the resistance-time characteristics of the sensor were tested at a test voltage of 1 V. The above preparation process and the prepared In2O3 / MXene-based sensor were tested and tested in combination with specific examples.

[0055] Example 1

[0056] Preparation of In2O3 and construction of In2O3-based sensor:

[0057] 0.864 g of indium nitrate hydrate (In(NO3)3·nH2O) was added to 15 ml of N-N- dimethylformamide (DMF), mixed and stirred uniformly for 10 minutes; then 2.4 g of polyvinylpyrrolidone (PVP) was added to the stirred solution and continued to stir for 3 h; the stirring speed was 500 r / min; the stirring solution was subjected to electrospinning operation, the voltage applied to the needle was 16 kv; the sample injection rate was 1 ml / h; the collector rotation speed was 100 r / min; the humidity control was 15% rh-20% rh; the spinning material was subjected to high-temperature annealing operation, the annealing heating rate was 5 ℃ / min; the highest annealing temperature was 400 ℃, the annealing time was 3 h, and the natural cooling to room temperature, obtaining pure In2O3.

[0058] The Au interdigital electrode was polished with magnesium oxide powder with particle sizes of 0.4 μm and 0.02 μm, respectively, and the polished electrode was first placed in anhydrous ethanol for ultrasonic cleaning for 6-10 minutes to remove organic dirt; then placed in ultrapure water for ultrasonic cleaning for 10-15 minutes to remove residual ethanol and magnesium oxide particles, and then dried the electrode surface with high-purity nitrogen; 3-5 mg of pure In2O3 was weighed and mixed with 20 μm-40 μm of anhydrous ethanol to obtain a uniform In2O3 anhydrous ethanol composite dispersion liquid, 3-5 μL of the In2O3 anhydrous ethanol composite dispersion liquid was removed with a pipette gun and dropped onto the surface of the Au interdigital electrode, and the In2O3-based sensor was obtained after 3-5 times of modification and heating drying on a heating table for 2-3 h.

[0059] Example 2

[0060] Preparation of In2O3 / MXene composite material and construction of In2O3 / MXene-based sensor:

[0061] First, 20 ml of HCl and 1.6 g of LiF were mixed and added to a beaker for 10 min; 1 g of Ti3AlC2 was added to the obtained mixed liquid and placed in an oil bath magnetic stirring pot for reaction for 36 h; the rotation speed was 400 r / min; the oil bath temperature was 38 ℃-42 ℃. The obtained reaction solution was subjected to centrifugation, ultrasonic, and freeze-drying for 60 h to obtain single-layer sheet-shaped MXene;

[0062] Then 0.864g of indium nitrate hydrate (In(NO3)3·nH2O) and 0.864mg of MXene were mixed with 7.5ml of N-N-dimethylformamide (DMF) respectively, and then 2.4g of polyvinylpyrrolidone (PVP) was added, and stirred for 12h; the stirred solution was electrospun, and the voltage applied to the needle during electrospinning was 16kv; the sample injection rate was 0.3ml / h; the collector rotation speed was 100r / min; the humidity control was 15%rh-20%rh, to obtain an In2O3 / MXene composite material precursor; the obtained material was subjected to high temperature annealing treatment, the annealing heating rate was 5℃ / min; the annealing temperature was 400℃, the annealing time was 3h, and the natural cooling to room temperature, to obtain an In2O3 / MXene composite material.

[0063] From Figure 1 and Figure 2 It can be seen that the In2O3 / MXene composite material is a single-layer sheet-wrapped rod-shaped nanoparticle, and the diameter of the rod-shaped nanoparticle is about 50nm. In addition, there are small and dense voids on the surface of the single-layer sheet-wrapped rod-shaped nanoparticle structure, which also provides abundant active sites for the attachment of oxygen, thereby obtaining a greater current response, and having better gas sensing performance than pure indium oxide, and enhancing the detection performance of triethylamine gas. Figure 3 is an element mapping diagram of the In2O3 / MXene composite material, as Figure 3 shown, wherein the In element and the O element belong to In2O3, and the C element, the N element and the Ti element belong to MXene. From Figure 3 it can be seen that the In element and the O element are in a uniformly dispersed state on the wrapped rod-shaped particles, which strongly confirms the successful synthesis of In2O3, and it can be seen that MXene is uniformly loaded on the surface of the In2O3 particles, so it can be proved that the In2O3 / MXene composite material is successfully prepared.

[0064] Figure 4 is an SEM image of MXene, and it can be seen that single-layer sheet-shaped MXene is successfully prepared, which lays a foundation for the successful loading of pure materials.

[0065] The Au interdigital electrode is polished with alumina powder with particle sizes of 0.4 μm and 0.02 μm, respectively, the polished electrode is first placed in anhydrous ethanol for ultrasonic cleaning for 6-10 minutes to remove organic dirt, then placed in ultrapure water for ultrasonic cleaning for 10-15 minutes to remove residual ethanol and magnesium oxide particles, and the electrode surface is dried with high-purity nitrogen; 3-5 mg of In2O3 / MXene composite material is weighed, mixed with 20 μm-40 μm anhydrous ethanol for ultrasonic homogenization to obtain a uniform In2O3 / MXene anhydrous ethanol composite dispersion liquid, 3-5 μL of the In2O3 / MXene anhydrous ethanol composite dispersion liquid is removed with a pipette gun and dropped on the surface of the Au interdigital electrode, a total of 3-5 times of modification is performed, and heating and drying are performed on a heating table for 2-3 h to obtain an In2O3 / MXene-based sensor.

[0066] Example 3

[0067] The In2O3-based sensor and the In2O3 / MXene-based sensor obtained according to the method of Example 1 and Example 2 are exposed to 1 ppm triethylamine, and the change curve of the sensor resistance with time is tested at a loading voltage of 1 V. Figure 5 As shown in the figure, it can be seen that the response time of the In2O3-based sensor is 120 s, and the recovery time is 219 s, while the response time of the In2O3 / MXene-based sensor is 1 s, and the recovery time is 11 s, which is greatly shortened compared with the response and recovery time of pure In2O3, and the composite material exhibits excellent triethylamine sensing performance.

[0068] Example 4

[0069] The In2O3 / MXene-based sensor obtained according to the method of Example 2 is continuously exposed to different triethylamine concentration environments, and the change curve of the sensor resistance with time is tested, and the change of the resistance with time is shown in Figure 6 and 7 As shown in the figure, the results show that as the triethylamine concentration gradually increases, the resistance value of the material gradually decreases, which exhibits the gas sensing behavior of an N-type semiconductor.

[0070] As can be seen from the above, the In2O3 / MXene-based sensor prepared by the application has high sensitivity and short response and recovery time for triethylamine detection, and has excellent performance in triethylamine detection, so it has great application potential for real-time detection and timely alarm of triethylamine leakage in various chemical processes using triethylamine as an industrial raw material, and systems related to triethylamine production, storage and transportation.

[0071] Example 5

[0072] The In2O3 / MXene-based sensor obtained according to the method of Example 2 is placed in a triethylamine environment with a concentration of 1 ppm for a long time, and the resistance-time curve of the sensor is tested every seven days, the long-term stability of the In2O3 / MXene-based sensor for triethylamine detection is evaluated by detecting the resistance-time change, and the change of sensitivity with time is as shown in Figure 8 Figure 8 It is shown in the above that the sensitivity of the material does not change much within a month, which proves that the material has good long-term stability. Then, the change of the response of the sensor to triethylamine is tested under different environmental humidity, and the response value of the material does not change much under the change of environmental humidity, which proves that the material has excellent moisture resistance. Figure 9

[0073] As can be seen from the above, the In2O3 / MXene-based sensor synthesized by the present application has excellent performance in the detection of triethylamine, and has great application potential in the real-time detection and timely alarm of triethylamine leakage in various chemical processes using triethylamine as an industrial raw material, systems related to the production, storage and transportation of triethylamine.

[0074] As described above, although the present application has been shown and described with reference to specific preferred embodiments, it is to be understood that such is by way of illustration and not of limitation. Various changes and modifications can be made therein without departing from the spirit and scope of the present application as defined in the appended claims.​​

Claims

1.A method for preparing an In 2O 3 / MXene composite material, wherein the In 2O 3 / MXene composite material is a single-layer sheet-shaped wrapped rod-shaped nanoparticle composed of an n-type semiconductor In 2O 3 coated by a p-type semiconductor metal two-dimensional material MXene, and a gap is distributed on the surface of the rod-shaped nanoparticle for providing abundant active sites for the attachment of oxygen, characterized in that, The specific steps for preparing the In2O3 / MXene composite material are as follows: Step 1, preparing single-layer sheet-shaped MXene; Step 2, mixing indium nitrate hydrate and MXene with N-N-dimethylformamide respectively, stirring uniformly to obtain two mixed solutions, then adding the two mixed solutions into polyvinylpyrrolidone, and stirring and mixing; Step 3, electrospinning treatment is performed on the solution after stirring and mixing to obtain an In2O3 / MXene composite material precursor; Step 4, annealing treatment is performed on the In2O3 / MXene composite material precursor to obtain single-layer sheet-shaped wrapped rod-shaped nanoparticles, which are the In2O3 / MXene composite material; In step 1, the specific steps for preparing single-layer sheet-shaped MXene are as follows: Step 1.1, mixing hydrochloric acid and lithium fluoride in a polyethylene beaker, and then heating and stirring in a magnetic stirrer; Step 1.2, adding aluminum titanium carbide for etching, and then performing centrifugation, ultrasonic treatment and freeze-drying treatment to obtain single-layer sheet-shaped MXene. 2.The method of claim 1, wherein the In 2O 3 / MXene composite is prepared by the steps of: preparing a mixture of In 2O 3 and MXene; and mixing the mixture with a solvent to prepare the In 2O 3 / MXene composite. In step 1.1, the mass ratio of hydrochloric acid to lithium fluoride is 1:10-1:20, the reaction time for heating and stirring in the magnetic stirrer is 5-15 minutes, the stirring speed range is 300-400 r / min, and the oil bath temperature range is 38-42°C. 3.The method of claim 1, wherein the In 2 O 3 / MXene composite is prepared by the steps of, In step 1.2, when adding aluminum titanium carbide, the mass ratio of aluminum titanium carbide to hydrochloric acid is 1:20-1:30, and the reaction time for etching is 36-48 hours. 4.The method of claim 1, wherein the In 2 O 3 / MXene composite is prepared by the steps of, In step 2, the mass ratio of indium nitrate hydrate to MXene is 10:1-200:1, the mass ratio of indium nitrate hydrate to N-N-dimethylformamide is 1:15, the mass ratio of MXene to N-N-dimethylformamide is 1:150-1:3000, and the stirring time with N-N-dimethylformamide is 5-15 minutes. 5.The method of claim 1, wherein the In 2 O 3 / MXene composite is prepared by the steps of, In step 2, after adding the two mixed solutions into polyvinylpyrrolidone, the mass ratio of indium nitrate hydrate to polyvinylpyrrolidone is 1:0.36, the stirring time is 12-18 hours, and the stirring speed range is 500-600 r / min. 6.The method of claim 1, wherein the In 2 O 3 / MXene composite is prepared by the steps of, In step 3, when performing electrospinning treatment, the voltage applied to the needle is 16-18 kV, the sample injection rate is 0.3-1 ml / h, the collector speed is 100 r / min, and the humidity control is 15-20% rh; in step 4, when performing annealing treatment, the annealing heating rate is 5°C / min, the highest annealing temperature is 400-700°C, the annealing time is 2.5-3.5 hours, and then the temperature is naturally reduced to room temperature. 7.The method of claim 1, wherein the In 2 O 3 / MXene composite is prepared by the steps of, The diameter of the rod-shaped nanoparticles is 30-70 nm.

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