Layer-by-layer in-situ growth method for preparing 2D-MoS2 / 1D-CuPc composite material and application thereof

Abstract

The invention provides a two-dimensional-molybdenum sulfide / one-dimensional copper phthalocyanine (2D-MoS2 / 1D-CuPc) composite material prepared by a layer-by-layer in-situ growth method and application of the two-dimensional-molybdenum sulfide / one-dimensional copper phthalocyanine composite material. The composite material is prepared from molybdenum sulfide (MoS2 nanosheets) and copper phthalocyanine (CuPc) films on the surfaces of the MoS2 nanosheets, and the CuPc films grow on the surfaces of the MoS2 nanosheets layer by layer in situ to form the composite material. A gas-sensitive sensing test result shows that the composite material has response performance to ammonia gas (NH3), acetone (C3H6O) and formaldehyde (CH20) gas. In addition, the 2D-MoS2 / 1D-CuPc composite material has the highest sensitivity to NH3, the response value to NH3 reaches 0.29, and the response time and the recovery time are 15 s and 12.5 s respectively. Through radar map analysis, the 2D-MoS2 / 1D-CuPc composite material shows selectivity to NH3 in three target gases including CH2O, C3H6O and NH3, so that identification and detection of the three target gases at room temperature are realized.

Description

Technical Field

[0001] The present invention belongs to the field of materials, and particularly relates to a method for preparing 2D-MoS2 / 1D-CuPc composite material by in-situ growth layer by layer and its application. Background Art

[0002] Molybdenum disulfide (MoS2), as a typical two-dimensional (2D) layered structure, has strong application potential in material preparation and optoelectronic property research due to its unique physical and chemical properties, high surface area ratio, low power and temperature. In addition, the ultra-high specific surface area, tunable bandgap (~1.8 eV) and excellent carrier mobility of MoS2 make it have a high affinity for most harmful gas molecules, showing great application prospects in the fields of gas detection and gas sensor research. In recent years, a large number of relevant literature reports on the gas-sensing properties of MoS2 and its composite materials have emerged. For example, Wang Hao et al. prepared MoS2 nanosheets based on two commonly used grinding solvents, N-methylpyrrolidone (NMP) and acetonitrile (ACN), by grinding-assisted liquid-phase exfoliation method. The results showed that the MoS2 nanosheets exfoliated with NMP had higher sensitivity to the target gas than those exfoliated with ACN, and the MoS2 nanosheets exfoliated with NMP showed fast response and recovery characteristics to 50-1000 ppm CH2O gas, and the response time and recovery time to 100 ppm CH2O were only 11 s and 0.6 s. Hai et al. obtained monolayer and multilayer MoS2 films by mechanical exfoliation method, and for the first time prepared a field-effect transistor (FET) for NO gas detection by photolithography technology. When MoS2 was in the range of 2-4 layers, the FET showed stable and sensitive characteristics (LOD was 0.8 ppm), but they found that the stability of the FET-type gas sensor based on monolayer MoS2 in air needed to be improved.

[0003] The research results show that although a single 2D MoS2 material has good gas-sensing response when used as a sensitive layer, due to the interaction between the sheets, MoS2 is prone to agglomeration and stacking. This leads to problems such as insufficient contact between the material and the target gas, resulting in a decrease in the sensitivity of the sensor and a long response time. In view of the current research status, researchers found that the heterostructure formed by the composite material and MoS2 nanosheets can effectively inhibit the agglomeration between MoS2 sheets, so that gas molecules can fully contact with the sensitive material, which helps to further improve the gas detection based on MoS2. Zhaoet al. prepared Bi2S3 / MoS2 by microwave hydrothermal method and tested the NO2 sensing performance from 100ppb to 10ppm. The test results showed that at 200℃ and 10ppm, the response and recovery time of the sensor were less than 25s. This is because the composite material of Bi2S3 and MoS2 formed a heterogeneous structure, which produced more active sites on the surface of the material, thereby improving the gas sensing response of the Bi2S3 / MoS2 sensor. M.Sangeetha et al. synthesized MoS2 / graphene nanocomposites by hydrothermal method, designed and manufactured molybdenum disulfide (MoS2) / graphene hybrid sensors, and evaluated the gas sensing performance of various gases (ethanol, methanol, acetone, CO, NO2 and formaldehyde) by cladding removal fiber method. The results showed that the interconnection of MoS2 spherical nanoparticles and two-dimensional graphene sheets provided a large active surface area, which was conducive to the gas molecules having more absorption characteristics in the presence of evanescent light. Compared with pure MoS2 sensors, the hybrid sensor exhibits excellent sensitivity (61%), fast response (22s) and recovery time (35s) ​​to NO2 gas, indicating that 2D MoS2 composites have better gas-sensing properties than MoS2 monomers. However, these methods cannot ensure uniform dispersion between MoS2 and the composite matrix and reliable bonding between them, and cannot obtain materials with better performance. In addition, there are problems such as high operating temperature and poor flexibility, which greatly restrict the practical application of sensors. At the same time, the current research on the preparation and gas-sensing properties of 2D MoS2 composites mainly focuses on the composite with inorganic materials, and there are few reports on organic materials and 2DMoS2 composites. Summary of the invention

[0004] The object of the present invention is to provide a 2D-MoS2 / 1D-CuPc composite material and a preparation method thereof.

[0005] The 2D-MoS2 / 1D-CuPc composite material of the present invention is made of MoS2 nanosheets and a copper phthalocyanine (CuPc) film on the surface thereof, wherein the CuPc film is in-situ grown layer by layer on the surface of the MoS2 nanosheets to form a composite material.

[0006] The thickness of the copper phthalocyanine film may be 200nm-1000nm;

[0007] Preferably, in the copper phthalocyanine (CuPc) film, CuPc nanowires are thin and uniformly grown on the surface of MoS2 nanosheets.

[0008] The 2D-MoS2 / 1D-CuPc composite material provided by the present invention is prepared by a method comprising the following steps:

[0009] 1) Prepare MoS2 nanosheets by a grinding-assisted liquid-phase exfoliation method;

[0010] 2) Use physical vapor transport method to in-situ grow CuPc layer by layer on the surface of MoS2 nanosheets to obtain 2D-MoS2 / 1D-CuPc composite

[0011] Disperse the MoS2 nanosheets obtained in step 1) in absolute ethanol to obtain a MoS2 nanosheet dispersion. Coat the obtained dispersion on a ceramic substrate. Place the obtained ceramic electrode sheet in a two-zone temperature-controlled tube furnace at a certain distance from the high-temperature zone. Use the vapor transport method to in-situ grow CuPc layer by layer on the surface of MoS2 nanosheets to form a composite material, thus obtaining it.

[0012] The operation of step 1) of the above method is as follows: Grind the MoS2 raw material, dry it, disperse the dried sample in an ethanol solution, perform ultrasonic treatment, and centrifuge to obtain MoS2 nanosheets;

[0013] The time of the grinding treatment can be 0.5 - 2 h, specifically 2 h;

[0014] Add an appropriate amount of NMP during the grinding process, specifically: add 5 ml - 50 mL of NMP per 100 mg of MoS2 raw material;

[0015] The drying is to dry the sample in a vacuum oven;

[0016] The drying time can be 8 - 16 h, specifically 12 h;

[0017] The ethanol solution can be a 30 - 60 vol% ethanol solution, specifically a 45 vol% ethanol solution;

[0018] The ultrasonic treatment time can be 0.5 - 1.5 h, specifically 1 h;

[0019] The centrifugation conditions are: centrifuge at 1500 r / min for 20 min.

[0020] In step 2) of the above method, the concentration of the MoS2 nanosheet dispersion can be 5 - 20 mg / mL, specifically 10 mg / mL;

[0021] The dispersion is coated on the ceramic substrate in a volume of 1 - 3 μL (specifically 2 μL);

[0022] The distance at a certain distance from the high-temperature zone can be: at a distance of 20 - 25 cm from the high-temperature zone, specifically at a distance of 20 cm - 22.7 cm from the high-temperature zone, more specifically at distances of 20 cm, 21.4 cm, and 22.7 cm from the high-temperature zone;

[0023] The temperature in the high-temperature zone can be 380 - 460 °C;

[0024] The transport agent used in the vapor transport method is nitrogen or argon;

[0025] The specific operation of the vapor transport method is as follows: Prepare a CuPc suspension, drip it onto a ceramic substrate coated with a MoS2 nanosheet dispersion to act as crystal nuclei, dry the precipitated CuPc, and place it in the high-temperature zone of a tube furnace. Grow it at a temperature of 400 °C and a N2 carrier gas flow rate of 20 ml / min for 4 h, that is, make CuPc grow in-situ layer by layer on the surface of MoS2 nanosheets to form a composite material.

[0026] The vapor transport method is a commonly used method. In the experiment, the nanowire morphologies, lengths, and deposition thicknesses at different positions are different.

[0027] Specifically, the growth (i.e., evaporation coating) by the vapor transport method can be carried out multiple times, specifically 1 - 4 times, more specifically 3 times, and the conditions are the same during each evaporation coating process.

[0028] The application of the above 2D-MoS2 / 1D-CuPc composite material as a gas-sensitive material also belongs to the protection scope of the present invention.

[0029] Specifically, the gas-sensitive material has at least one of the following uses:

[0030] 1) Detect any one of NH3, C3H6O, and CH2O;

[0031] 2) Prepare a gas-sensitive sensor for detecting any one of NH3, C3H6O, and CH2O.

[0032] The present invention also provides a gas-sensitive sensor for detecting any one of NH3, C3H6O, and CH2O, and the gas-sensitive sensor contains a sensing chip based on the above 2D-MoS2 / 1D-CuPc composite material.

[0033] The present invention uses a method of in-situ growth by physical vapor transport to grow CuPc thin films with different thicknesses on a MoS2 substrate, obtaining a 2D-MoS2 / 1D-CuPc composite material. It is characterized by means such as XRD, XPS, SEM, EDS, and FTIR. The results prove that CuPc is successfully compounded on the surface of MoS2. The gas-sensing test results show that the composite material has a response performance to ammonia, acetone, and formaldehyde gases. In addition, the 2D-MoS2 / 1D-CuPc composite material has the highest sensitivity to NH3, with a response value to NH3 reaching 0.29, and the response and recovery times are 15 s and 12.5 s respectively. Through radar chart analysis, among the three target gases of CH2O, C3H6O, and NH3, the 2D-MoS2 / 1D-CuPc composite material shows selectivity for NH3, realizing the identification and detection of the three target gases at room temperature. Due to the different Fermi levels between the MoS2 and CuPc materials, a depletion layer is formed. After contacting the target gas, oxygen desorption and adsorption of target gas molecules release electrons, balancing the electrons in the depletion layer, thereby reducing the thickness of the depletion layer and improving the gas-sensing performance. Description of the Drawings

[0034] Figure 1 SEM images of the MoS2 nanosheets prepared in Example 1 of the present invention (a); SEM images of the 2D-MoS2 / 1D-CuPc composite material at different positions ((b) A1, (c) A2, (d) A3).

[0035] Figure 2 EDS maping spectra of the 2D-MoS2 / 1D-CuPc composite material prepared in Example 1 of the present invention.

[0036] Figure 3 XRD patterns of CuPc, MoS2, and 2D-MoS2 / 1D-CuPc composite materials.

[0037] Figure 4 Fourier infrared spectra of CuPc, MoS2, and 2D-MoS2 / 1D-CuPc composite materials (the inset is a partial enlarged view).

[0038] Figure 5 XPS spectra of MoS2 and 2D-MoS2 / 1D-CuPc composite materials.

[0039] Figure 6 Response curves of the sensors (A1, A2, A3) of the 2D-MoS2 / 1D-CuPc composite material to 1000 ppm NH3, C3H6O, and CH2O.

[0040] Figure 7The (a, b, c) average responses and (e, f, g) recovery times of A1, A2, A3 to NH3, C3H6O, CH2O.

[0041] Figure 8 The average response of the 2D-MoS2 / 1D-CuPc (A1, A2, A3) sensor to NH3.

[0042] Figure 9 The radar chart of the responses of A1, A2, A3 to NH3, C3H6O, CH2O. Specific embodiments

[0043] The present invention will be further described in detail below in conjunction with specific embodiments. The provided embodiments are only for clarifying the present invention, rather than limiting the scope of the present invention. The following provided embodiments can be used as a guide for those of ordinary skill in the art to make further improvements, and do not constitute any limitation to the present invention in any way.

[0044] In the experimental methods of the following embodiments, unless otherwise specified, they are all conventional methods, carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following embodiments, unless otherwise specified, can all be obtained from commercial channels.

[0045] The sources of the materials used in the following embodiments:

[0046] Molybdenum disulfide (MoS2) and copper phthalocyanine (CuPc) were purchased from Sigma Aldrich. Potassium nitrate (KNO3) was purchased from Xuzhuangzi, Dongli District, Tianjin. Absolute ethanol (C2H6O), acetonitrile (CH3CH), N-methylpyrrolidone (C5H9NO), formaldehyde (CH2O), ammonia water (NH3) and acetone (C3H6O) were purchased from Tianjin Zhiyuan Chemical Reagent Co., Ltd. The above chemicals are all of analytical grade (AR) and do not require further purification.

[0047] Example 1. Preparation of 2D-MoS2 / 1D-CuPc composite material

[0048] 1) Preparation of MoS2 nanosheets

[0049] The MoS2 nanosheets were prepared by a grinding-assisted liquid-phase exfoliation method: First, 100 mg of MoS2 raw material was weighed and placed in an agate mortar and ground for 2 h. During the grinding process, an appropriate amount of NMP (20 mL) was added. After grinding, the sample was placed in a vacuum oven and dried for 12 h. After drying, the sample was dispersed in 20 ml of a 45 vol% ethanol solution and ultrasonicated for 1 h, and then the dispersion was centrifuged for 20 min (1500 r / min) to obtain MoS2 nanosheets, and finally it was dried in air for standby.

[0050] 2) Fabrication of 2D-MoS2 / 1D-CuPc Composite Material Sensor

[0051] The composite material was prepared by physical vapor transport method: First, the prepared MoS2 nanosheets were dispersed in absolute ethanol at a concentration of 10 mg / ml to obtain a MoS2 nanosheet dispersion. Then, the dispersion was evenly coated (2 μl of MoS2 nanosheet dispersion) on three ceramic substrates to fabricate MoS2-based sensing chips. Finally, the three ceramic electrode chips were placed in a two-zone temperature-controlled tube furnace at positions 20 cm, 21.4 cm, and 22.7 cm away from the high-temperature zone, respectively. The gas-phase transport method was used to grow CuPc layer by layer in situ on the surface of MoS2 nanosheets to form a composite material (specific operation: First, 1 mg of purified CuPc was placed in a beaker, 20 ml of ethanol was added, sealed and sonicated for 1 h. After sonication, the suspension was allowed to stand at room temperature for 24 h; then the CuPc suspension was dropped onto the ceramic substrate coated with MoS2 nanosheet dispersion to act as nuclei to induce the growth of CuPc micro-nano wires; finally, the precipitated CuPc was dried and placed in the high-temperature zone of the tube furnace to grow at a temperature of 400 °C and a N2 carrier gas flow rate of 20 ml / min for 4 h), obtaining a sensing chip based on 2D-MoS2 / 1D-CuPc composite material. For convenience of description, the three electrode chips were named A1, A2, and A3 in the text. Under the same conditions, the samples of A1, A2, and A3 were vapor-deposited 1-4 times, and the influence of the vapor-deposition times on the gas-sensing performance of the composite material was compared.

[0052] Example 2: Material Characterization and Testing

[0053] The structure of the samples was measured by X-ray diffraction (XRD) (Bruker D8 Advance, operating with Cu-Kα radiation at 40 kV and 40 mA) and Fourier transform infrared (FTIR) spectrometer (Bruker VERTEX 70, Germany); the morphology of the samples was studied by field emission scanning electron microscope (JSM-7610F Plus), and the elemental content of the materials was measured by energy-dispersive X-ray spectroscopy (EDS); the surface chemical properties of the samples were measured by X-ray photoelectron spectroscopy (XPS K-Alpha + , USA).

[0054] Figure 1 The SEM morphology of the 2D-MoS2 / 1D-CuPc composite material is shown. Figure 1 (a) is the SEM morphology of pure MoS2 nanosheets, Figure 1 (b, c, d) are the SEM morphologies of the samples of A1, A2, and A3. Figure 1(b) shows that the CuPc nanowires evaporated on the A1 electrode are relatively dense and have uneven sizes. Most of the nanowires are thicker because CuPc is in the β-phase state at a high deposition temperature, and CuPc forms large-sized ribbon-shaped single crystals. Figure 1 (c) shows that the CuPc evaporated on the A2 electrode is relatively uniform, but the nanowires agglomerate seriously. Figure 1 (d) shows that the CuPc nanowires evaporated on the A3 electrode are thinner and grow uniformly on the surface of MoS2 nanosheets. This is because at a low deposition temperature (A3), CuPc is in the α-phase state, forming nanowire clusters, particles, and other small-sized morphologies. The smaller the size of the CuPc nanowires, the larger the surface area of the sample, which can greatly improve the adsorption and responsiveness of gas sensing performance.

[0055] Figure 2 Shown is the EDS maping spectrogram of the A3 electrode. It can be clearly seen from the figure that the 2D-MoS2 / 1D-CuPc composite material is composed of six elements, namely C, N, O, Cu, Mo, and S, without other impurity elements, indicating that the prepared 2D-MoS2 / 1D-CuPc composite material has a high purity.

[0056] Figure 3 Shown are the XRD patterns of CuPc nanowires, MoS2 nanosheets, and the 2D-MoS2 / 1D-CuPc (A3) composite material. It can be seen from the XRD patterns that two typical diffraction peaks appear at 7° and 9.2°, corresponding to the (-1,0,1) and (1,0,1) crystal planes of β-phase CuPc, respectively. The typical diffraction peaks at 14.4°, 32.6°, 33.5°, 35.8°, 39.5°, 44.2°, and 49.8° correspond to the (0,0,2), (1,0,0), (1,0,1), (1,0,2), (1,0,3), (1,0,4), and (1,0,5) crystal planes of MoS2. The XRD test results show that CuPc has grown successfully on the surface of MoS2.

[0057] Among them, CuPc micro-nanowires are prepared by physical vapor transport method using a two-stage temperature-controlled tube furnace. To improve the yield of micro-nanowires, the substrate in the growth area is pretreated as follows: First, 1 mg of purified CuPc is placed in a beaker, 20 ml of ethanol is added, sealed and ultrasonically treated for 1 h. After the ultrasonic treatment, the suspension is left standing at room temperature for 24 h; then the CuPc suspension is dropped onto the ceramic substrate to act as crystal nuclei to induce the growth of CuPc micro-nanowires; finally, the precipitated CuPc is dried and placed in a tube furnace to grow at a temperature of 400 °C and a N2 carrier gas flow rate of 20 ml / min for 4 h to obtain CuPc micro-nanowires with a length of more than 100 μm.

[0058] Figure 4The Fourier transform infrared spectra of CuPc, MoS2, and 2D-MoS2 / 1D-CuPc composites are shown. It can be seen from the figure that absorption peaks of CuPc, A1, A2, and A3 all appear at the same positions. Among them, 726 cm -1 , 752 cm -1 , 800 cm -1 belong to the out-of-plane bending vibration of -C-H-. 874 cm -1 , 900 cm -1 , 1065 cm -1 , 1086 cm -1 , 1119 cm -1 belong to the stretching vibration of -C-C-. 1166 cm -1 and 1333 cm -1 belong to the stretching vibration of -C-O-. 1285 cm -1 belongs to the in-plane stretching vibration of -O-H-. 1418 cm -1 , 1465 cm -1 , 1507 cm -1 and 1611 cm -1 belong to the stretching vibration of -C=C- phthalocyanine skeleton. In addition, from Figure 4 the inset, it can be seen that MoS2, A1, A2, and A3 all have absorption peaks at 468 cm -1 . And with the change of the position of the electrode sheet, the intensity of the MoS2 absorption peak decreases significantly, which may be because with the decrease of the deposition temperature, the growth thickness of CuPc on the surface of MoS2 nanosheets increases.

[0059] Figure 5 Shown are the XPS spectra of pure MoS2 nanosheets and 2D-MoS2 / 1D-CuPc composites. Figure 5 As shown in Fig. a, two spectral peaks appear at 955.55 and 935.59 eV in the composite, which are attributed to Cu2p 1 / 2 and Cu2p 3 / 2 . Figure 5 Fig. b shows the Mo3d spectra of MoS2 nanosheets and 2D-MoS2 / 1D-CuPc composites. For pure MoS2 nanosheets, two sharp peaks can be seen at 228.23 eV and 232.28 eV, corresponding to the 3d 4+ and 3d 3 / 2 of Mo 5 / 2 , respectively. In addition, the weak peak at 234.77 eV is a typical signal of Mo 6+ 3d 3 / 2 in the Mo-O bond, indicating that the introduction of O is caused by defects or vacancies on the surface of MoS2. At the same time, it can be seen that the peak shifts towards higher energy, indicating a decrease in the electron cloud density around MoS2. Figure 5c is the energy spectrum of S2p. Two spectral peaks can be observed at 161.88 eV and 163.28 eV, corresponding to S2 in MoS2 - . Figure 5 d is the C1s spectrum of the composite material. The spectral peak at 288.5 eV is mainly attributed to the O-C=O bond, the peak at 285.42 eV is mainly attributed to the C-O-H bond, and the peak at 284.8 eV is mainly attributed to the C-C bond. Figure 5 e is the spectrum of N element in the composite material. The main peak at 339.12 eV is attributed to N1s Figure 5 f is the O1s spectrum of molybdenum disulfide and the composite material. The peak at 532.80 eV is attributed to the adsorption of oxygen and becomes .

[0060] Example 3. Gas sensing performance test

[0061] First, apply a voltage of 2 V to the 2D-MoS2 / 1D-CuPc composite material sensing chips (A1, A2, A3) and age them in air for about 48 h to ensure good sensing stability. Then use NH3, C3H6O, and CH2O solutions to obtain gas environments of 1000 ppm NH3, C3H6O, and CH2O respectively. Use a Keithley 2636b workstation (Keithley Instruments, Inc.) to evaluate the gas sensing performance of the sensor at room temperature under a constant voltage of 2 V. Place the gas sensor in different types of gas environments for testing. After the current reaches a stable value, switch to the next gas environment to continue testing. The current response of the gas sensing performance test is defined as: Response=(I G -I R ) / I R , where I R and I G are the currents of the sensor in the reference gas and the target gas respectively. The response time is defined as the time period when the current of the sensor reaches 90% of the response value after exposure to the target gas, and the recovery time is defined as the time period when the sensor current becomes 10% of the response value after removing the target gas.

[0062] A self-built gas sensing detection platform is used to study the gas sensing performance of the gas sensor constructed with in-situ grown 2D-MoS2 / 1D-CuPc composite material. Figure 6Gas sensing property test diagrams of CuPc evaporated layer by layer on the surface of MoS2 at different positions as shown. The test results show that at room temperature, sensors A1, A2, and A3 all have relatively stable gas responses to 1000 ppm of NH3, C3H6O, and CH2O. With the increase in the number of evaporation times (a total of 4 evaporation times), the response magnitudes of A1, A2, and A3 to the three target gases first increase and then decrease, and when evaporating for the third time, all sensors exhibit the best gas performance. In addition, it can also be seen that the 2D-MoS2 / 1D-CuPc composite material after evaporation is most sensitive to NH3. Among them, the average responses of sensor A1 to NH3 after four evaporations are 0.070, 0.082, 0.225, and 0.063 respectively; for sensor A2, the average responses to NH3 increase to 0.076, 0.100, 0.274, and 0.075 respectively; sensor A3 shows a relatively high gas sensing response to NH3, and the average responses of the sensor after four evaporations are 0.115, 0.125, 0.29, and 0.076 respectively. The results show that the response value of the sensor to NH3 reaches the highest of 0.29 after the third evaporation, and the response and recovery times are 15 s and 12.5 s respectively. Combining the characterization test results, this is because the CuPc nanowires grown on the A3 electrode sheet at a low deposition temperature have more uniform sizes and grow more uniformly on the surface of the MoS2 nanosheets, providing richer edge active sites for gas molecules, thereby enhancing the gas sensing performance.

[0063] Figure 7 Shown are the average response magnitudes and recovery times of A1, A2, and A3 to NH3, C3H6O, and CH2O. It can be seen from Figures (a-c) that the response of the 2D-MoS2 / 1D-CuPc composite material to the target gas first increases and then decreases with the increase in the number of CuPc evaporation times. The statistical results show that the best responses of A1, A2, and A3 to NH3, C3H6O, and CH2O are 0.29, 0.11, and 0.10 respectively, and the corresponding recovery times are 12.5 s, 8.2 s, and 7.0 s respectively. The recovery times of the sensors are all less than 16 s (Figures d-f), reflecting a relatively fast recovery characteristic. This is because the heterojunction formed by the uniformly sized CuPc nanowires and the MoS2 nanosheets with a super high specific surface area greatly increases the electron transport and transfer, making the MoS2 / CuPc composite material show a fast response and recovery to the target gas.

[0064] Figure 8 Shown is the comparison of the average responses of MoS2 nanosheets and 2D-MoS2 / 1D-CuPc composite materials to NH3. The gas sensing property of the composite material is significantly higher than that of single MoS2. When evaporating CuPc (A3) for the third time, the gas sensing property is the best.

[0065] Figure 9As can be seen from the radar chart, the 2D-MoS2 / 1D-CuPc composite material has the highest sensitivity to NH3. For the three gases of NH3, C3H6O, and CH2O, the three devices show selectivity for NH3.

[0066] In this invention, the 2D-MoS2 / 1D-CuPc (A1, A2, and A3) composite material was prepared by a layer-by-layer in-situ growth method and used as a gas-sensitive material. It was characterized by means such as XRD, XPS, SEM, EDS, and FTIR. The results proved that CuPc was successfully compounded on the surface of MoS2. The gas-sensing test results showed that the responses of the A1, A2, and A3 sensors to ammonia, acetone, and formaldehyde gases were related to the number of times of in-situ growth of CuPc. The response reached the highest after the growth times reached 3 times (A3). In addition, it can also be seen that the 2D-MoS2 / 1D-CuPc composite material has the highest sensitivity to NH3, the response value to NH3 reaches 0.29, and the response and recovery times are 15 s and 12.5 s respectively. Through radar chart analysis, among the three target gases of CH2O, C3H6O, and NH3, the 2D-MoS2 / 1D-CuPc composite material shows selectivity for NH3, realizing the identification and detection of four target gases at room temperature. Due to the different Fermi levels between the MoS2 and CuPc materials, a depletion layer is formed. After contacting the target gas, oxygen desorption and target gas molecule adsorption release electrons, balancing the electrons in the depletion layer, thereby reducing the thickness of the depletion layer and improving the gas-sensing performance.

[0067] The above has detailed the present invention. For those skilled in the art, without departing from the purpose and scope of the present invention and without unnecessary experiments, the present invention can be implemented within a relatively wide range under equivalent parameters, concentrations, and conditions. Although specific embodiments of the present invention are given, it should be understood that the present invention can be further improved. In short, according to the principle of the present invention, this application intends to include any changes, uses, or improvements to the present invention, including changes made using conventional techniques known in the art that are outside the scope disclosed in this application.

Claims

1. 2D-MoS2 / 1D-CuPc composite material, characterized in that: The composite material is made of MoS2 nanosheets and CuPc films on their surfaces, wherein the CuPc films are in-situ grown layer by layer on the surface of the MoS2 nanosheets to form the composite material; The copper phthalocyanine film has a thickness of 200nm-1000nm.

2. A method for preparing the composite material according to claim 1, comprising the following steps: 1) preparing MoS2 nanosheets by a grinding-assisted liquid phase exfoliation method; 2) Physical vapor transport method was used to in situ grow CuPc layer by layer on the surface of MoS2 nanosheets to obtain 2D-MoS2 / 1D-CuPc composite materials The MoS2 nanosheets obtained in step 1) are dispersed in anhydrous ethanol to obtain a MoS2 nanosheet dispersion, and the obtained dispersion is coated on a ceramic substrate. The obtained ceramic electrode sheet is placed in a two-stage temperature-controlled tubular furnace at a distance from the high-temperature zone, and a gas phase transport method is used to make CuPc grow in situ layer by layer on the surface of the MoS2 nanosheet to form a composite material.

3. The method according to claim 2, characterized in that The operation of step 1) is: grinding the MoS2 raw material, drying it, dispersing the dried sample into an ethanol solution, ultrasonically treating it, and centrifuging it to obtain MoS2 nanosheets; The grinding time is 0.5-2h; N-methylpyrrolidone NMP was added during the grinding process; The ethanol solution is a 30-60 vol% ethanol solution; The ultrasonic treatment time is 0.5-1.5h; The centrifugal conditions are: 1500r / min for 20min.

4. The method according to claim 2, characterized in that: In step 2), the concentration of the MoS2 nanosheet dispersion is 5-20 mg / mL; The dispersion is coated on a ceramic substrate in a volume of 1-3 μL; The distance from the high temperature zone is 20-25 cm from the high temperature zone; The temperature of the high temperature zone is 380-460°; The transporting agent used in the gas phase transport method is nitrogen or argon.

5. The method according to claim 2, characterized in that: The gas phase transport growth method is performed multiple times, specifically 1 to 4 times, and the conditions during each gas phase transport growth method are the same.

6. Use of the 2D-MoS2 / 1D-CuPc composite material according to claim 1 as a gas-sensitive material.

7. The use according to claim 6, characterized in that: The gas-sensitive material has at least one of the following uses: 1) Detect any one of NH3, C3H6O and CH2O; 2) Prepare a gas sensor, wherein the gas sensor is used to detect any one of NH3, C3H6O and CH2O.

8. A gas sensor for detecting any one of NH3, C3H6O and CH2O, characterized in that: The gas sensor contains a sensor chip based on the 2D-MoS2 / 1D-CuPc composite material according to claim 1.

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