A Ti3C2T x / TiO2 / CuO nanocomposite materials and gas sensors based thereon

Abstract

This invention discloses a Ti3C2T x / TiO2 / CuO nanocomposite material and a gas sensor based thereon, the nanocomposite material being a multilayer Ti3C2T obtained by etching x The composite material prepared by this invention is prepared by a hydrothermal reaction of a mixed solution of powder and copper acetate. The composite material possesses gas-sensitive properties, based on the constructed Ti3C2T... x The TiO2 / CuO gas sensor features fast response, high sensitivity, good stability, good selectivity, and low detection limit, enabling accurate and rapid detection of ethanol gas.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial preparation technology, and particularly to a Ti3C2T x Synthesis method of / TiO2 / CuO nanocomposite material and its application in gas-sensitive element. Background Technology

[0002] Ethanol is a common volatile organic compound (VOC) and an important industrial raw material, widely used in food, medicine, agriculture, and chemical industries. However, when exposed to high temperatures, open flames, or oxidizers, it is highly flammable and can easily ignite, causing fires. Furthermore, ethanol is volatile; large amounts of ethanol vapor can adversely affect the human nervous and circulatory systems, and damage vision and respiratory mucosa. According to the Occupational Safety and Health Administration, the recommended maximum ethanol exposure level is 1000 × 10⁻⁶. -6 In certain special circumstances, such as chemical plant leaks and checks on drivers under the influence of alcohol, rapid detection is crucial, even at low concentrations. Therefore, high-performance ethanol gas sensors play a vital role in preventing public safety incidents.

[0003] Semiconductor metal oxide (SMO) gas sensors offer advantages such as low cost, simple integration, and good stability. However, their high detection limit, high operating temperature, and poor selectivity often limit their widespread application. Ti3C2T x As a novel two-dimensional material, Ti3C2T has shown great potential for VOC detection in recent years due to its abundant specific surface area, diverse functional groups, and excellent electrical conductivity. x Combining materials with metal oxides can effectively improve the defects of traditional metal oxides and enhance the selectivity, stability, and response recovery performance of sensors. Summary of the Invention

[0004] To address the shortcomings of existing SMO gas sensors, this invention provides a Ti3C2T x The synthesis method of / TiO2 / CuO nanocomposite material and its application in gas sensors are proposed to greatly improve the detection performance of ethanol gas.

[0005] To achieve its objectives, the present invention employs the following technical solution:

[0006] This invention first discloses a Ti3C2T x The preparation method of / TiO2 / CuO nanocomposite materials includes the following steps:

[0007] Step S1: Prepare etching solution;

[0008] Step S2: Prepare multilayer Ti3C2T by mixing Ti3AlT2 powder with etching solution. x powder;

[0009] Step S3: Place the Ti3C2T x The powder was ultrasonically dispersed in deionized water, copper acetate was added and stirred, then sodium hydroxide solution was added to adjust the pH to 10.5-11.5, and after ultrasonic stirring, Ti3C2T was synthesized. x Precursor liquid for / TiO2 / CuO nanocomposites;

[0010] Step S4: The precursor solution is added to the reactor, and after hydrothermal reaction, Ti3C2T is obtained by washing and drying. x / TiO2 / CuO nanocomposite material.

[0011] Further, the etching solution in step S1 is prepared as follows: 2g of LiF powder is added to a mixed solution of 20mL of deionized water and 20mL of HCl (9M) solution, and stirred to obtain the etching solution. This whole process is carried out in a polytetrafluoroethylene beaker.

[0012] Further, the specific method of step S2 is as follows: Ti3AlT2 powder is added to the etching solution and stirred in a water bath at 60°C for 48 hours. Then, it is centrifuged and washed at 9000 rpm until the pH of the supernatant is between 5.5 and 6.5. The precipitate is then freeze-dried to obtain multilayer Ti3C2T x powder.

[0013] Further, in step S3, the Ti3C2T x The mass ratio of the powder to the copper acetate is 1 to 8:1.

[0014] Furthermore, in step S4, the temperature of the hydrothermal reaction is 180°C and the reaction time is 12 hours.

[0015] The present invention also discloses Ti3C2T prepared according to the above preparation method. x Application of TiO2 / CuO nanocomposite materials in gas sensors. This gas sensor uses Ti3C2T... x / TiO2 / CuO nanocomposite materials can be used as gas-sensitive materials to detect volatile organic compounds such as ethanol.

[0016] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0017] This invention synthesizes a ternary heterostructure composite material Ti3C2T using a simple one-step hydrothermal method. xTiO2 / CuO was synthesized and used to prepare an ethanol gas sensor element. During the preparation of the composite material, Ti3C2T was used in a hydrothermal environment. x Because the main body is oxidized to form titanium dioxide, thus forming a PN heterojunction and ternary synergistic effect, a PNP-type material structure is ultimately formed, which greatly improves the gas sensing performance of the Ti3C2T based on it. x The TiO2 / CuO gas sensor features fast response, high sensitivity, good stability, good selectivity, and low detection limit. In particular, it exhibits excellent repeatability and long-term stability, and can operate at room temperature, significantly reducing power consumption. This invention ultimately yields a highly stable, highly selective ethanol gas sensor capable of operating at room temperature. Attached Figure Description

[0018] Figure 1 The image shown is a scanning electron microscope (SEM) image of the TTC2 nanocomposite material prepared in the embodiments of the present invention.

[0019] Figure 2 The XRD pattern of the TTC2 nanocomposite material prepared in the embodiments of the present invention;

[0020] Figure 3 This is a transmission electron microscope (TEM) image of the TTC2 nanocomposite material prepared in the embodiments of the present invention;

[0021] Figure 4 The response recovery curve of the TTC2 nanocomposite material prepared in the embodiments of the present invention is shown below.

[0022] Figure 5 The Ti3C2T prepared in the embodiments of the present invention x Sensitivity curves of CuO, TTC1, TTC2, TTC3, and TTC4 nanocomposites;

[0023] Figure 6 The sensitivity of the TTC2 nanocomposite material sensor prepared in the embodiments of the present invention to different gases;

[0024] Figure 7 This is a long-term stability test of the sensor made of TTC2 nanocomposite material in the embodiments of the present invention. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention Ti3C2T will be described below with reference to the accompanying drawings and embodiments. xThe synthesis method of / TiO2 / CuO nanocomposite materials and the gas sensor based thereon are described in more detail. The following content is merely illustrative and explanatory of the inventive concept. Those skilled in the art may make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the inventive concept or exceed the scope defined in these claims, all of which should fall within the protection scope of this invention.

[0026] Example 1

[0027] A Ti3C2T x The synthesis method of / TiO2 / CuO nanocomposites includes the following steps:

[0028] (1) Prepare etching solution;

[0029] Add 20 mL of deionized water and 20 mL of HCl solution (9 M) to a polytetrafluoroethylene beaker and mix thoroughly. Add 2 g of LiF powder to the mixture and stir for 30 min to obtain the etching solution.

[0030] (2) Preparation of multilayer Ti3C2T x powder;

[0031] Add 1g of Ti3AlT2 powder to the above etching solution and stir in a water bath at 60℃ for 48h. After cooling, the mixture is washed sequentially with anhydrous ethanol and deionized water at 9000rpm until the pH of the supernatant is around 6. Then, freeze-dry the centrifuged precipitate to obtain the final multilayer Ti3C2T. x powder;

[0032] (3) Preparation of Ti3C2T x Precursor liquid for / TiO2 / CuO nanocomposites;

[0033] The above Ti3C2T x The powder was ultrasonically dispersed in 40 mL of deionized water, and 0.16 g of copper acetate powder was added and stirred. Then, sodium hydroxide solution was added to adjust the pH to around 11, and after ultrasonic stirring, Ti3C2T was synthesized. x Precursor liquid for / TiO2 / CuO nanocomposites;

[0034] (4) Preparation of Ti3C2T x / TiO2 / CuO nanocomposite materials;

[0035] The above precursor solution was added to the reactor and kept at 180°C for 12 hours in a forced-air drying oven. After cooling, it was washed sequentially by centrifugation with anhydrous ethanol and deionized water, and finally obtained by freeze-drying.x / TiO2 / CuO nanocomposite material.

[0036] In this embodiment, the Ti3C2T in step (3) is adjusted. x The powders were 20 mg, 40 mg, 80 mg, and 160 mg in weight, respectively, to ensure that the final product contained Ti3C2T. x The masses of these composite materials accounted for 23.8%, 38.5%, 55.6%, and 71.4% of the total mass of the composite materials, respectively, and the resulting composite materials were named TTC1, TTC2, TTC3, and TTC4.

[0037] Figure 1 The Ti3C2T obtained in this embodiment x Scanning electron microscope (SEM) image of TiO2 / CuO nanocomposite TTC2. The image shows the presence of Ti3C2T... x The surface is uniformly covered with TiO2 particles and CuO nanosheets.

[0038] Figure 2 The Ti3C2T obtained in this embodiment x The XRD pattern of the / TiO2 / CuO nanocomposite TTC2 shows that the characteristic diffraction peaks of all three materials are present.

[0039] Figure 3 The Ti3C2T obtained in this embodiment x A transmission electron microscope (TEM) image of the TiO2 / CuO nanocomposite material TTC2. The image shows Ti3C2T... x The three materials—TiO2 particles and CuO nanosheets—are tightly bonded together.

[0040] To test the Ti3C2T obtained in this embodiment x The performance of TiO2 / CuO nanocomposite materials as gas-sensitive materials for gas sensors was demonstrated by fabricating gas-sensitive elements using the following method: Ti3C2T... x The / TiO2 / CuO nanocomposite material was ground with ethanol in a mortar until fully mixed, then evenly coated onto a planar electrode. After infrared drying for two hours and cooling, it was soldered onto a circuit board base. After aging at room temperature for two days, the preparation was complete and ready for testing.

[0041] The prepared gas-sensitive element was used for detection as follows:

[0042] 1. Response performance test:

[0043] Ethanol gas was detected using a WS-30A gas-sensitive element testing system. 0.23 mL of 99.7% pure ethanol solution (equivalent to 5 ppm) was injected into the evaporation stage of an 18L gas distribution box. The resistance change of the gas sensor was measured, and the results are shown below. Figure 4 The results showed that the sensor's resistance changed immediately after the ethanol solution was injected, with response recovery times of 32 s and 261 s, respectively, and its sensitivity was 230% (S = |R_s|). a -R g | / R a ×100%, where S is the sensitivity and R is the percentage. a Let R be the initial resistance. g The resistance after contact with the target gas indicates that the prepared sensor has a good response to the ethanol solution. Figure 5 Ti3C2T was showcased x The response recovery curves of CuO, TTC1, TTC2, TTC3, and TTC4 sensors to 10 ppm ethanol vapor were shown, with the TTC2 sensor showing the best response.

[0044] 2. Selective testing:

[0045] The WS-30A gas-sensitive element testing system was used at room temperature. Different types of standard gases, all with a concentration of 10 ppm, were injected into the gas distribution box. The resistance change of the gas sensor after contact with these gases was measured, and the sensitivity was calculated. The test results are shown below. Figure 6 It can be seen that the sensor resistance changes little after injecting other types of gases besides ethanol, indicating that the prepared sensor exhibits good selectivity for ethanol gas.

[0046] 3. Long-term stability test:

[0047] The WS-30A gas-sensitive element testing system was used. The test temperature was room temperature, and the ethanol concentration was 10 ppm. Tests were conducted every 5 days, with ethanol gas injected into the gas mixing chamber. After 60 days of use, the sensor's sensitivity to 10 ppm ethanol gas showed a change of less than 5%, indicating good sensor stability. The test results are shown in the figure. Figure 7 .

[0048] 4. Comparison between this study and existing work:

[0049] For existing ethanol gas sensors and related Ti3C2T x The performance of the gas sensors is compared and shown in Table 1. The results show that the sensor obtained by the present invention has excellent performance.

[0050] Table 1

[0051]

[0052] Thank 1 person for a snowball fight:

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[0058] [6]Liu X, Jiang L, Jiang X, et al. Design of superior ethanol gas sensor based on indium oxide / molybdenum disulfide nanocomposite via hydrothermalroute[J]. Applied Surface Science, 2018.

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[0061] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A Ti3C2T x The method for preparing / TiO2 / CuO nanocomposite materials is characterized by, Includes the following steps: Step S1: Prepare etching solution; Step S2: Prepare multilayer Ti3C2T by mixing Ti3AlT2 powder with etching solution. x powder; Step S3: Place the Ti3C2T x The powder was ultrasonically dispersed in deionized water, copper acetate was added and stirred, then sodium hydroxide solution was added to adjust the pH to 10.5-11.5, and after ultrasonic stirring, Ti3C2T was synthesized. x The precursor solution for the / TiO2 / CuO nanocomposite material; the Ti3C2T x The mass ratio of the powder to the copper acetate is 1~8:1; Step S4: The precursor solution is added to the reactor and subjected to hydrothermal reaction at 180 °C for 12 h. After washing and drying, Ti3C2T is obtained. x / TiO2 / CuO nanocomposite material.

2. The Ti3C2T according to claim 1 x The method for preparing / TiO2 / CuO nanocomposite materials is characterized by, The etching solution in step S1 is prepared as follows: 2 g of LiF powder is added to a mixture of 20 mL of deionized water and 20 mL of 9 MHCl solution, and stirred to obtain the etching solution.

3. The Ti3C2T according to claim 1 x The method for preparing / TiO2 / CuO nanocomposite materials is characterized by, The specific method for step S2 is as follows: Ti3AlT2 powder is added to the etching solution and stirred in a water bath at 60 ℃ for 48 h. Then, it is centrifuged and washed at 9000 rpm until the pH of the supernatant is between 5.5 and 6.

5. The precipitate is then freeze-dried to obtain multilayer Ti3C2T x powder.

4. A Ti3C2T prepared by the preparation method according to any one of claims 1 to 3 x / TiO2 / CuO nanocomposite material.

5. A Ti3C2T according to claim 4 x Application of TiO2 / CuO nanocomposites in gas sensors.

6. A gas sensor, characterized in that: The gas sensor uses the Ti3C2T as described in claim 4. x / TiO2 / CuO nanocomposite material as a gas-sensitive material.

7. The gas sensor according to claim 6, characterized in that: The gas sensor is used to detect ethanol.

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