Preparation method and application of ZnO material with tetragonal bipyramid-like structure

Abstract

The invention discloses a preparation method and application of a ZnO material with a tetragonal bipyramid-like structure, relates to a preparation method of a metal oxide semiconductor material, and aims to solve the technical problems of high working temperature and low response value of an existing metal oxide semiconductor sensor for detecting di-n-butylamine and diisopropylamine. The method comprises the following steps: dissolving Zn (NO3) 2.6 H2O, citric acid, urea and a complexing and constructing agent into water to obtain a precursor solution, wherein the complexing and constructing agent is oxalic acid or ammonium acetate; the precursor solution is subjected to a hydrothermal reaction and then calcined, the ZnO material with the tetragonal bipyramid-like structure is obtained, and the response of the ZnO material serving as a gas sensitive material to 100 ppm di-n-butylamine is 300.6; the response to 100 ppm of diisopropylamine is 271.5, and the fluorescent probe can be used in the field of detection of di-n-butylamine or diisopropylamine.

Description

Technical Field

[0001] The present invention relates to the technical field of metal oxide semiconductor material preparation, and in particular to the preparation and sensitive performance application of zinc oxide (ZnO) material. Background Art

[0002] Dibutylamine and diisopropylamine are widely used in chemical production and pharmaceutical fields such as dyes, pesticides, medicines, emulsifiers, and corrosion inhibitors as organic synthesis reagents. However, when dibutylamine and diisopropylamine are widely used and exposed for a long time, their toxicity and strong irritation often cause great harm to human eyes, skin, lungs, respiratory system, cardiovascular system, and immune system, and in severe cases, even cause death. In addition, dibutylamine and diisopropylamine are easy to cause explosions, with explosion volumes ranging from 0.6 to 6.8% and 1.1 to 7.1%, respectively, which seriously pollute the environment. Therefore, it is very meaningful to be able to quickly and accurately monitor the above two toxic and harmful gases in real time.

[0003] Metal oxide semiconductors have been widely used in environmental monitoring and detection of hazardous gas leaks due to their good stability, good selectivity, high sensitivity, portability, low manufacturing cost and ease of large-scale production. Currently, metal oxide semiconductor sensitive materials for detecting di-n-butylamine and diisopropylamine include TiO2, MoO3, WO3, etc. The article "Corn stigma template-assisted synthesis of single crystal MoO3 elliptical nanosheets for chemiresistive detection of dibutylamine vapor" published in the 408th volume of Sensors and Actuators B-Chemical in 2024, the operating temperature of the sensor is 170 ° C, and the response value to 100 ppm dibutylamine is 254.8. The article "Controllable assembly of corn cob-like h / γ-WO3 hierarchical structure for enhanced sensitive detection of dibutylamine vapor" published in the 415th volume of Sensors and Actuators B-Chemical in 2024 The working temperature of the sensor is 252 ° C, and the response value to 100 ppm of di-n-butylamine is 105. The article "Porous MoO3 nanosheets for conductometric gas sensors to detect diisopropylamine" published in Volume 382 of "Sensors and Actuators B-Chemical" in 2023, the working temperature of the sensor is 217 ° C, and the response value to 10 ppm of diisopropylamine is 30.4.

[0004] The metal oxide semiconductor sensors prepared above still have the disadvantages of high operating temperature and low response value. Summary of the invention

[0005] The present invention aims to solve the technical problems of high operating temperature and low response value of the existing metal oxide semiconductor sensor for detecting di-n-butylamine and diisopropylamine, and provides a preparation method and application of a tetragonal bipyramidal structure ZnO material.

[0006] The preparation method of the tetragonal bipyramidal structure ZnO material of the present invention is carried out according to the following steps:

[0007] 1. Weigh Zn(NO3)2·6H2O, citric acid, urea and complexing agent in a mass ratio of 1:(0.5-0.6):(0.35-1.5):(0.6-0.8) and add them into water, stir for 60-80 minutes to obtain a precursor solution; wherein the complexing agent is oxalic acid or ammonium acetate;

[0008] 2. Transfer the precursor liquid into a polytetrafluoroethylene-lined reactor, place the reactor in an oven at 70-160°C for 6-36 hours for hydrothermal reaction, centrifuge after the reaction, wash the solid phase with water and ethanol in turn, and dry to obtain a precursor;

[0009] 3. Place the precursor in a high-temperature furnace, heat it to 400-700°C and calcine it for 2-3 hours to obtain a tetragonal bipyramidal ZnO material.

[0010] Furthermore, the drying in step 2 is carried out at a temperature of 60 to 70° C. for 6 to 12 hours.

[0011] The application of the tetragonal bipyramid ZnO material is to use the tetragonal bipyramid ZnO material as a gas-sensitive material for the detection of di-n-butylamine or diisopropylamine.

[0012] The present invention uses oxalic acid or ammonium acetate as a complexing agent. In a hydrothermal process, under the action of the complexing agent, a tetragonal bipyramidal ZnO precursor is formed, in which two tetragonal pyramids are connected by two grooves as a "bridge". Then, through calcination, nearly spherical nanoparticles are uniformly and orderly cross-linked and stacked to form a tetragonal bipyramidal structure. At the same time, the surface is relatively rough and has grooves distributed on the surface. Oxalic acid and ammonium acetate, as complexing agents of the tetragonal bipyramidal morphology, play a decisive role in the tetragonal bipyramidal morphology.

[0013] The tetragonal bipyramidal ZnO material of the present invention has a high response to di-n-butylamine and diisopropylamine, and the response to 100 ppm di-n-butylamine is 300.6 at an operating temperature of 133°C, and the response to 100 ppm diisopropylamine is 271.5 at an operating temperature of 217°C. The material can be used in the field of di-n-butylamine and diisopropylamine detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a scanning electron microscope photograph of the precursor obtained in step 2 in Example 1;

[0015] Figure 2 is a scanning electron microscope photograph of ZnO-550 obtained in step 3 in Example 1;

[0016] Figure 3 The XRD spectra of the precursors and the tetragonal bipyramidal ZnO materials ZnO-550, ZnO-500, ZnO-450 and ZnO-400 prepared in Examples 1 to 4;

[0017] Figure 4 This is a scanning electron microscope photo of the ZnO material prepared in Comparative Example 1;

[0018] Figure 5 It is a response value curve diagram of the ZnO-550 prepared in Example 1 tested at different concentrations of di-n-butylamine at a working temperature of 133°C.

[0019] Figure 6 It is a response value curve diagram of the ZnO-550 prepared in Example 1 tested with different concentrations of diisopropylamine at a working temperature of 217°C;

[0020] Figure 7 This is a scanning electron microscope photograph of the tetragonal bipyramid-like ZnO material prepared in Example 5. DETAILED DESCRIPTION

[0021] The beneficial effects of the present invention are verified by the following examples.

[0022] Embodiment 1: The preparation method of the tetragonal bipyramidal ZnO material of this embodiment is carried out according to the following steps:

[0023] 1. Weigh 0.20 g of Zn(NO3)2·6H2O, 0.11 g of citric acid, 0.11 g of urea and 0.14 g of oxalic acid and dissolve them in 25 mL of ultrapure water. Place the mixed solution on a magnetic stirrer and stir for 80 min to obtain a precursor solution.

[0024] 2. Transfer the precursor solution into a 50 mL polytetrafluoroethylene-lined reactor, and then place the reactor in an oven at 100°C for 12 hours for hydrothermal reaction. After the reaction is completed, centrifuge and separate the solid phase by washing it with ultrapure water and ethanol three times respectively, and then dry it in an oven at 70°C for 8 hours to obtain a precursor.

[0025] 3. Place the precursor in a high-temperature furnace, heat it to 550°C and calcine it for 2 hours to obtain a tetragonal bipyramidal ZnO material, recorded as ZnO-550.

[0026] Example 2: This example is different from Example 1 in that the calcination in step 3 is 500°C, and the other steps and parameters are the same as those in Example 1. The obtained tetragonal bipyramidal ZnO material is recorded as ZnO-500.

[0027] Example 3: This example is different from Example 1 in that the calcination in step 3 is 450°C, and the other steps and parameters are the same as those in Example 1. The obtained tetragonal bipyramidal ZnO material is recorded as ZnO-450.

[0028] Example 4: This example is different from Example 1 in that the calcination in step 3 is 400°C, and the other steps and parameters are the same as those in Example 1. The obtained tetragonal bipyramidal ZnO material is recorded as ZnO-400.

[0029] The scanning electron microscope photo of the precursor obtained in step 2 in Example 1 is as follows Figure 1 As shown, the scanning electron microscope photo of ZnO-550 obtained in step 3 is as follows Figure 2 As shown, from Figure 1 It can be seen that the precursor is a tetragonal bipyramid structure, with two trenches as bridges connecting two tetragonal bipyramids. Its surface is smooth, the tetragonal bipyramids are evenly dispersed, and most of them are micron-sized structures. Figure 2 It can be seen that compared with the precursor, the tetragonal bipyramidal structure of ZnO-550 is composed of uniformly distributed and nearly spherical nanoparticles that are orderly cross-linked and stacked. After calcination, its surface becomes relatively rough, the size of the nanoparticles increases, and the depth of the grooves becomes shallower.

[0030] The precursors prepared in Examples 1 to 4 and the tetragonal bipyramidal ZnO materials ZnO-550, ZnO-500, ZnO-450 and ZnO-400 were subjected to XRD tests, and the obtained XRD spectra were as follows: Figure 3 As shown, from Figure 3 It can be seen that the precursor ZnO is transformed into hexagonal ZnO after calcination, and with the increase of calcination temperature, it is found that the peaks of (100), (002), (101), (102), (110) and (103) crystal planes gradually increase, indicating that the crystallinity is enhanced. It also shows that ZnO-550 has the best crystallinity.

[0031] Comparative Example 1: In this comparative example, no complexing agent is added. The difference between this comparative example and Example 1 is that oxalic acid is omitted in step 1, and the other steps and parameters are the same as Example 1 to obtain ZnO material.

[0032] The scanning electron microscope photo of the ZnO material prepared in Comparative Example 1 is as follows Figure 4 As shown, from Figure 4It can be seen that the ZnO material is in the form of micron spheres. Comparison Example 1 shows that the formation of the tetragonal bipyramidal ZnO in Example 1 is mainly related to oxalic acid, which acts as a complexing agent and a structural agent for the tetragonal bipyramidal morphology, and plays a decisive role in the tetragonal bipyramidal morphology. In Comparative Example 1, citric acid and urea work together to form nanocrystals with Zn salt, thereby forming micron spherical ZnO.

[0033] The method for detecting di-n-butylamine or diisopropylamine using the tetragonal bipyramidal ZnO material ZnO-550 prepared in Example 1 as a gas-sensitive material is as follows:

[0034] 1. Mix 0.010g ZnO-550 and 1 drop of pine alcohol evenly, apply it to the surface of Al2O3 ceramic tube, and then calcine it in a furnace at 300℃ for 1h to remove the pine alcohol binder;

[0035] 2. Insert a resistance wire into the Al2O3 ceramic tube and weld its two ends to the hexagonal base to obtain the sensor;

[0036] 3. Then insert the ZnO-550 sensor into the equipment channel of the JF02F gas sensor test system; at the same time, use the static gas distribution method to prepare di-n-butylamine or diisopropylamine samples, use a micro-syringe to extract di-n-butylamine or diisopropylamine liquid samples, and then pass them into a 10L volume test bottle equipped with a vacuum system, and the test gas is diluted by air to maintain a suitable detection environment; finally, insert the sensor into the test bottle and start the gas-sensitive performance test.

[0037] The response curve of ZnO-550 to different concentrations of di-n-butylamine at a working temperature of 133°C is shown in the figure below. Figure 5 As shown, from Figure 5 It can be seen that 0.5-100ppm di-n-butylamine is directly close to the response in a linear relationship. When the concentration of di-n-butylamine is 100ppm, the response is 300.6. When the concentration of di-n-butylamine is greater than 100ppm, the response value gradually increases. When the concentration of di-n-butylamine reaches 400ppm, the response value is slightly greater than the response value of 300ppm di-n-butylamine, indicating that the detection of 400ppm di-n-butylamine is close to saturation.

[0038] The response curve of ZnO-550 to different concentrations of diisopropylamine at a working temperature of 217°C is shown in the figure below. Figure 6 As shown, from Figure 6It can be seen that 0.01-30ppm diisopropylamine is directly close to the response in a linear relationship. When the concentration of di-n-butylamine is greater than 30ppm, the response value gradually increases. When the concentration of diisopropylamine is 100ppm, the response value is 271.5. When the concentration of diisopropylamine reaches 400ppm, the response value is slightly greater than the response value of 300ppm diisopropylamine, indicating that the detection of 400ppm diisopropylamine is close to saturation.

[0039] The response value of the micron-spherical ZnO material prepared in Comparative Example 1 to 100 ppm di-n-butylamine at a working temperature of 133° C. is 55.3, and the response value of the micron-spherical ZnO material prepared in Comparative Example 1 to 100 ppm diisopropylamine at a working temperature of 217° C. is 38.2. This indicates that the tetragonal bipyramidal ZnO crystal has a better detection effect than the micron-spherical ZnO material.

[0040] Example 5: This example uses ammonium acetate as a complexing agent. The preparation method of the tetragonal bipyramidal ZnO material of this example is carried out according to the following steps:

[0041] 1. Weigh 0.23 g of Zn(NO3)2·6H2O, 0.12 g of citric acid, 0.14 g of urea and 0.14 g of ammonium acetate and dissolve them in 25 mL of ultrapure water. Place the mixed solution on a magnetic stirrer and stir for 80 min to obtain a precursor solution.

[0042] 2. Transfer the precursor solution into a 50 mL polytetrafluoroethylene-lined reactor, place the reactor in an oven at 100°C for 12 hours for hydrothermal reaction, centrifuge after the reaction, wash the solid phase with ultrapure water and ethanol three times respectively, and then dry it in an oven at 70°C for 8 hours to obtain a precursor;

[0043] 3. Place the precursor in a high-temperature furnace, heat it to 550°C and calcine it for 2 hours to obtain a tetragonal bipyramidal structure ZnO material.

[0044] The scanning electron microscope photograph of the tetragonal bipyramidal ZnO material prepared in Example 5 is as follows: Figure 7 As shown, from Figure 7 It can be seen that tetragonal bipyramidal ZnO crystals can also be obtained using ammonium acetate as a complexing agent.

[0045] The response value of the tetragonal bipyramidal ZnO material prepared in Example 5 to 100 ppm di-n-butylamine at an operating temperature of 133° C. is 179.2, and the response value to 100 ppm diisopropylamine at an operating temperature of 217° C. is 135.7.

Claims

1. A method for preparing a tetragonal bipyramidal ZnO material, characterized in that: The method proceeds as follows:

1. Weigh Zn(NO3)2·6H2O, citric acid, urea and complexing agent in a mass ratio of 1:(0.5-0.6):(0.35-1.5):(0.6-0.8) and add them into water, stir for 60-80 minutes to obtain a precursor solution; wherein the complexing agent is oxalic acid or ammonium acetate; 2. Transfer the precursor liquid into a polytetrafluoroethylene-lined reactor, place the reactor in an oven at 70-160°C for 6-36 hours for hydrothermal reaction, centrifuge after the reaction, wash the solid phase with water and ethanol in turn, and dry to obtain a precursor; 3. Place the precursor in a high-temperature furnace, heat it to 400-700°C and calcine it for 2-3 hours to obtain a tetragonal bipyramidal ZnO material.

2. The method for preparing a tetragonal bipyramidal ZnO material according to claim 1, characterized in that: The drying in step 2 is carried out at a temperature of 60 to 70° C. for 6 to 12 hours.

3. Application of a tetragonal bipyramidal ZnO material prepared by the method of claim 1, characterized in that: The application is to use the tetragonal bipyramidal structure ZnO material as a gas-sensitive material for the detection of di-n-butylamine or diisopropylamine.

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