阅读说明：本技术 一种基于介孔In2O3-NiO敏感材料的三乙胺气体传感器及其制备方法 (In based on mesoporous2O3Triethylamine gas sensor of-NiO sensitive material and preparation method thereof ) 是由 孙鹏 于淇 卢革宇 王天双 刘方猛 闫旭 王晨光 刘晓敏 于 2021-08-18 设计创作，主要内容包括：一种基于介孔In-(2)O-(3)-NiO敏感材料的三乙胺气体传感器及其制备方法,属于半导体氧化物气体传感器技术领域。由外表面带有金电极的Al-(2)O-(3)陶瓷管衬底、涂覆在衬底外表面的介孔In-(2)O-(3)-NiO敏感材料和置于衬底内的镍铬加热线圈组成。本发明利用Ni-MOF为模板,通过将Ni～(2+)与In～(3+)交换,将Ni-MOF转化为In/Ni-MOF可以防止在煅烧过程中对Ni-MOF多孔网状骨架和分级结构的破坏。介孔In-(2)O-(3)-NiO中空复合材料具有大比表面积(55.5m～(2)g～(-1)),可为VOCs分子提供足够的渗透途径,最大化活性位点,增强VOCs捕获能力,使传感器灵敏度大幅度提高。(In based on mesoporous 2 O 3 A triethylamine gas sensor of a NiO sensitive material and a preparation method thereof, belonging to the technical field of semiconductor oxide gas sensors. Al with gold electrode on outer surface 2 O 3 Ceramic tube substrate and mesoporous In coated on outer surface of substrate 2 O 3 NiO sensitive material and NiCr heating coil placed inside the substrate. The invention uses Ni-MOF as a template by adding Ni 2+ And In 3+ The exchange, converting Ni-MOF to In/Ni-MOF, may prevent the disruption of the Ni-MOF porous network framework and hierarchical structure during calcination. Mesoporous In 2 O 3 -NiO hollow composite material with large specific surface area (55.5 m) 2 g ‑1 ) The method can provide enough permeation path for VOCs molecules, maximize active sites, enhance the capture capacity of VOCs and greatly improve the sensitivity of the sensor.)

1. In based on mesoporous₂O₃The triethylamine gas sensor of the NiO sensitive material is an indirectly heated structure and is composed of Al with two parallel, annular and mutually separated gold electrodes on the outer surface₂O₃Ceramic tube substrate coated with Al₂O₃Semiconductor metal oxide gas sensitive material on ceramic tube outer surface and gold electrode and Al-containing alloy₂O₃The nickel-chromium heating coil in the ceramic tube comprises the following components: the sensitive material is MOF-derived mesoporous In₂O₃-NiO sensitive material and is prepared by the following steps:

(1) mixing 15-20 mL of DMF (N, N-dimethylformamide) and 15-20 mL of ethylene glycol, and then mixing 1mmol of Ni (NO)₃)₂·6H₂Adding O and 1.5mmol of terephthalic acid into the mixture, stirring for 20-40 minutes to obtain a uniformly mixed solution, transferring the uniformly mixed solution into a hydrothermal kettle, heating to react for 4-8 hours at 140-160 ℃, cooling to room temperature after the reaction is finished, centrifuging and cleaning the generated precipitate for multiple times by using ethanol, and then centrifuging the centrifugal product at 70 ℃. (E)Drying for 10-15 hours at 90 ℃ to obtain a Ni-MOF precursor;

(2) dissolving 2g of polyvinylpyrrolidone (PVP) in 30-50 mL of ethanol, weighing 200mg of the Ni-MOF precursor obtained in the step (1), adding the Ni-MOF precursor into the mixed solution, performing ultrasonic treatment on the obtained mixed solution for 3-8 minutes, stirring for 20-30 minutes, standing at room temperature for 10-15 hours, performing centrifugal cleaning on the generated precipitate for multiple times by using ethanol, and drying the centrifugal product at 70-90 ℃ for 10-15 hours to obtain a PVP-Ni-MOF material;

(3) adding 30mg of PVP-Ni-MOF obtained In the step (2) and indium nitrate into 10-15 mL of ethanol, wherein the mass of the indium nitrate is 15-25% of that of the PVP-Ni-MOF, carrying out ultrasonic treatment for 10-20 minutes, stirring for 10-20 minutes, reacting for 20-30 hours at room temperature, centrifuging and cleaning the generated precipitate for multiple times by using ethanol, and drying the centrifugal product at 70-90 ℃ for 10-15 hours to obtain an In/Ni-MOF precursor;

(4) calcining the In/Ni-MOF precursor obtained In the step (3) at the temperature of 450-550 ℃ for 1.5-3.0 hours to obtain mesoporous In derived based on MOF₂O₃-NiO sensitive material.

2. The mesoporous In-based material of claim 1₂O₃-a triethylamine gas sensor of NiO sensitive material, characterized in that: al (Al)₂O₃The inner diameter of the ceramic tube is 0.6-0.8 mm, the outer diameter is 1.0-1.5 mm, the length is 4-5 mm, the width of a single annular gold electrode is 0.4-0.5 mm, and the distance between two gold electrodes is 0.5-0.6 mm; and a platinum wire lead is led out of the gold electrode, and the length of the platinum wire lead is 4-6 mm.

3. The mesoporous In-based material of claim 1₂O₃The preparation method of the triethylamine gas sensor of the NiO sensitive material comprises the following steps:

(1) taking mesoporous In₂O₃The NiO sensitive material and the deionized water are mixed into uniform slurry, a small amount of the slurry is dipped by a brush and evenly coated on the Al₂O₃Forming a sensitive material film with the thickness of 40-50 mu m on the outer surfaces of the ceramic tube and the gold electrode;

(2) will be provided withAl coated with sensitive material film₂O₃Baking the ceramic tube under an infrared lamp for 10-15 minutes, and drying the sensitive material, and then, adding Al₂O₃Calcining the ceramic tube at 150-250 ℃ for 1.5-3.0 hours; then enabling a nickel-chromium heating coil with a resistance value of 30-40 omega to penetrate through Al₂O₃The interior of the ceramic tube is used as a heating wire, and finally the device is welded and packaged according to an indirectly heated gas sensitive element to prepare the In based on the mesoporous₂O₃A triethylamine gas sensor of NiO sensitive material.

Technical Field

The invention belongs to the technical field of semiconductor oxide gas sensors, and particularly relates to mesoporous In-based₂O₃A triethylamine gas sensor of a NiO sensitive material and a preparation method thereof.

Background

Triethylamine, as a common volatile organic solvent, has a strong ammonia odor, is flammable, explosive, toxic and highly irritating, and is an important raw material for producing preservatives, catalysts, pesticides and synthetic fuels. Prolonged exposure to triethylamine can cause respiratory irritation and significant damage to the skin and mucous membranes. At present, some scientific research groups find that the concentration of triethylamine is closely related to the freshness of seafood products, and the triethylamine can be used as the identification standard of the freshness of the seafood. Therefore, in order to ensure the safety of the related chemical industry workers, the environmental quality of the chemical plant and the freshness of the seafood related to food safety, it is important to develop a simple, efficient, low-cost and stable triethylamine gas sensor.

Among the numerous gas sensors, metal oxide semiconductor gas sensors have received much attention because of their simple preparation method, their ease of miniaturization, their cost effectiveness, and their high sensitivity. In recent years, a great number of researchers research the relationship between the microstructure of the metal oxide semiconductor sensitive material and the gas sensing performance, and the metal oxide semiconductor sensitive material with the mesoporous hierarchical structure is found to be capable of effectively improving the sensing performance of the sensor due to the fact that the metal oxide semiconductor sensitive material has a large specific surface area, a high-efficiency sensing active site and a structure which is beneficial to gas adsorption and diffusion.

In recent years, with the rise of research on metal oxides derived from Metal Organic Frameworks (MOFs), mesoporous metal oxides derived from MOFs as templates are widely applied to the fields of supercapacitors, lithium ion batteries, catalysts, gas sensors and the like due to the advantages of large specific surface area, larger pore volume, rich mesoporous structure, adjustable morphology and the like. Meanwhile, recent studies indicate that the cation exchange method can be used for preparing a bimetallic metal organic framework composed of two different semiconductor materials, and the bimetallic metal organic framework can be used as a precursor or a self-sacrificial template to produce a composite material with a layered porous nano structure. In with mesoporous and hollow hierarchical structure is synthesized by solvothermal method and subsequent cation exchange₂O₃NiO composite material for improving the sensing performance of the sensor.

Disclosure of Invention

The invention aims to provide mesoporous In based on MOF (Metal organic framework) derivation₂O₃A triethylamine gas sensor of a NiO sensitive material and a preparation method thereof.

The invention prepares the mesoporous In by a simple solvothermal method and an ion exchange method₂O₃-NiO sensitive material. The invention uses Ni-MOF as a template by adding Ni²⁺Ions and In³⁺And ion exchange is carried out, so that the Ni-MOF is converted into In/Ni-MOF, and the damage to the porous network framework and the hierarchical structure of the Ni-MOF In the calcining process can be prevented. Meanwhile, the mesoporous In prepared by the invention₂O₃-NiO sensitive material is In₂O₃And NiO, and has a large specific surface area (55.5 m)²g^-1) The method can provide enough permeation path for VOCs molecules, maximize active sites, enhance the capture capacity of VOCs and greatly improve the sensitivity of the sensor. Based on mesoporous In₂O₃The NiO sensitive material sensor shows excellent sensitivity (33.9-100ppm) and selectivity to triethylamine, and has good long-term stability and repeatability.

The invention relates to mesoporous In based on MOF derivation₂O₃A triethylamine gas sensor of NiO sensitive material,is indirectly heated structure, and is composed of Al with two parallel, annular and separated gold electrodes on its external surface₂O₃Ceramic tube substrate coated with Al₂O₃Semiconductor metal oxide gas sensitive material on ceramic tube outer surface and gold electrode and Al-containing alloy₂O₃The nickel-chromium heating coil in the ceramic tube comprises the following components: the sensitive material is MOF-derived mesoporous In₂O₃-NiO sensitive material and is prepared by the following steps:

(1) mixing 15-20 mL of DMF (N, N-dimethylformamide) and 15-20 mL of ethylene glycol, and then mixing 0.8-1.2 mmol of Ni (NO)₃)₂·6H₂Adding O and 1.3-1.7 mmol of terephthalic acid into the mixture, stirring for 20-40 minutes to obtain a uniformly mixed solution, transferring the uniformly mixed solution into a hydrothermal kettle, heating the mixture at 140-160 ℃ for reaction for 4-8 hours, cooling the reaction product to room temperature after the reaction is finished, centrifuging and cleaning the generated precipitate for multiple times by using ethanol, and drying the centrifugal product at 70-90 ℃ for 10-15 hours to obtain a Ni-MOF precursor;

(2) dissolving 1.8-2.2 g of polyvinylpyrrolidone (PVP) in 30-50 mL of ethanol, weighing 180-220 mg of the Ni-MOF precursor obtained in the step (1), adding the Ni-MOF precursor into the mixed solution, performing ultrasonic treatment on the obtained mixed solution for 3-8 minutes, stirring the mixed solution for 20-30 minutes, standing the mixed solution at room temperature for 10-15 hours, performing multiple centrifugal cleaning on the generated precipitate by using ethanol, and drying the centrifugal product at 70-90 ℃ for 10-15 hours to obtain a PVP-Ni-MOF material;

(3) adding 28-32 mg of PVP-Ni-MOF obtained In the step (2) and indium nitrate into 10-15 mL of ethanol, wherein the indium nitrate is 15-25% of the mass of the PVP-Ni-MOF, carrying out ultrasonic treatment for 10-20 minutes, stirring for 10-20 minutes, reacting at room temperature for 20-30 hours, centrifuging and cleaning the generated precipitate for multiple times by using ethanol, and drying the centrifugal product at 70-90 ℃ for 10-15 hours to obtain an In/Ni-MOF precursor;

(4) calcining the In/Ni-MOF precursor obtained In the step (3) at the temperature of 450-550 ℃ for 1.5-3.0 hours to obtain mesoporous In derived based on MOF₂O₃-NiO sensitive material.

The invention is described inMesoporous In based on MOF derivation₂O₃The preparation method of the triethylamine gas sensor of the NiO sensitive material comprises the following steps:

(1) taking mesoporous In₂O₃The NiO sensitive material and the deionized water are mixed into uniform slurry, a small amount of the slurry is dipped by a brush and evenly coated on the Al₂O₃Forming a sensitive material film with the thickness of 40-50 mu m on the outer surfaces of the ceramic tube and the gold electrode; al (Al)₂O₃The inner diameter of the ceramic tube is 0.6-0.8 mm, the outer diameter is 1.0-1.5 mm, the length is 4-5 mm, the width of a single annular gold electrode is 0.4-0.5 mm, and the distance between two gold electrodes is 0.5-0.6 mm; a platinum wire lead is led out of the gold electrode, and the length of the platinum wire lead is 4-6 mm;

(2) al coated with sensitive material film₂O₃Baking the ceramic tube under an infrared lamp for 10-15 minutes, and drying the sensitive material, and then, adding Al₂O₃Calcining the ceramic tube at 150-250 ℃ for 1.5-3.0 hours; then enabling a nickel-chromium heating coil with a resistance value of 30-40 omega to penetrate through Al₂O₃The interior of the ceramic tube is used as a heating wire, and finally the device is welded and packaged according to an indirectly heated gas sensitive element to prepare the mesoporous In derived based on the MOF₂O₃A triethylamine gas sensor of NiO sensitive material.

The invention has the following advantages:

(1) MOF-derived mesoporous In was prepared by solvothermal reaction and subsequent cation exchange₂O₃-a NiO composite.

(2) By mixing Ni²⁺Ions and In³⁺Ion exchange, which converts Ni-MOF into In/Ni-MOF, can prevent the destruction of the porous network framework and the layered structure of Ni-MOF during the calcination process.

(3) Mesoporous In prepared by the invention based on MOF derivation₂O₃The NiO sensitive material sensor shows excellent sensitivity and selectivity to triethylamine (33.9-100 ppm).

(4) Mesoporous In prepared by the invention based on MOF derivation₂O₃The triethylamine gas sensor of the NiO sensitive material has simple manufacturing process, is cheap and is suitable for industrial mass production.

Drawings

FIG. 1: (a-c) is an SEM topography of the NiO material under the low power and the high power; (d-f) is In₂O₃SEM topography at low and high magnification for NiO composites;

FIG. 2: NiO and In₂O₃-XRD pattern of NiO composite;

FIG. 3: sensitivity curves of the sensors for the comparative example and the example at different working temperatures for 100ppm triethylamine gas;

FIG. 4: the selectivity curves of the sensors in the comparative example and the example at 200 ℃ for 7 gases to be measured of 100ppm are shown;

FIG. 5: (a) the transient response curve of the sensor at 200 ℃ for different concentrations of triethylamine gas in the embodiment is shown; (b) the sensitivity curves of the sensor in the examples at 200 ℃ for different concentrations of triethylamine gas are shown.

As shown in FIG. 1, the NiO material can be seen in FIGS. 1(a-c) as a hollow chip structure consisting of many particles. In can be seen from FIG. 1(d-f)₂O₃The NiO composite material is a hollow chip structure consisting of nano sheets, namely a hollow structure.

As shown In FIG. 2, it can be seen that the XRD spectrum of the obtained material has the same standard NiO card and In₂O₃The standard cards matched and no other miscellaneous peaks appeared.

As shown in FIG. 3, the optimum operating temperatures of the sensors in the comparative example and the example are both 200 ℃, and the sensitivities to 100ppm triethylamine at the optimum operating temperatures are 10.6 and 33.9, respectively, so that the gas sensing performance of the sensors in the example is greatly improved compared with the sensors in the comparative example.

As shown in fig. 4, the sensors in the comparative example and the example have excellent selectivity to triethylamine at 200 ℃, but the selectivity of the sensor in the example is significantly higher than that of the comparative example.

As shown in FIG. 5, the sensor in the embodiment has good transient response recovery performance for triethylamine gas with different concentrations (0.5-200ppm) at the optimal working temperature of 200 ℃, the sensitivity of the device is increased along with the increase of the concentration of the triethylamine gas, and a good linear growth relationship is shown between the sensitivity and the concentration, the lower limit of detection of the sensor in the embodiment on the triethylamine gas can reach 0.5ppm, and the sensitivity is 1.2.

Note: the sensitivity of the device (P-type semiconductor) is defined in the test reducing atmosphere as the ratio of the resistance in the tested atmosphere to the resistance in air, i.e. S-R_g/R_a。

Detailed Description

Comparative example 1:

a triethylamine gas sensor based on mesoporous NiO sensitive material derived from MOF and a preparation method thereof comprise the following steps:

(1) 16mL of DMF (N, N-dimethylformamide) and 16mL of ethylene glycol were mixed, and 1mmol of Ni (NO) was added₃)₂·6H₂Adding O and 1.5mmol of terephthalic acid into the mixture, stirring the mixture for 30 minutes to obtain a uniformly mixed solution, transferring the uniformly mixed solution into a hydrothermal kettle, heating the mixture to react for 6 hours at 150 ℃, cooling the mixture to room temperature after the reaction is finished, centrifuging and cleaning the generated precipitate for multiple times by using ethanol, drying the centrifuged product for 12 hours at 80 ℃ to obtain a Ni-MOF precursor, wherein the mass of the obtained product is 150 mg.

(2) And (2) calcining the Ni-MOF precursor obtained in the step (1) at 500 ℃ for 2 hours to obtain a mesoporous NiO sensitive material derived based on MOF, wherein the mass of the obtained product is 35 mg.

(3) Mixing the mesoporous NiO sensitive material and deionized water to form uniform slurry, dipping a small amount of the slurry by a brush, and uniformly coating the slurry on Al₂O₃Forming a sensitive material film with the thickness of 45 mu m on the outer surfaces of the ceramic tube and the gold electrode; al (Al)₂O₃The inner diameter of the ceramic tube is 0.7mm, the outer diameter is 1.25mm, the length is 4.5mm, the width of a single annular gold electrode is 0.45mm, and the distance between two gold electrodes is 0.55 mm; a platinum wire lead is led out of the gold electrode, and the length of the platinum wire lead is 5 mm;

(4) al coated with sensitive material film₂O₃Baking the ceramic tube under an infrared lamp for 10 minutes, and drying the sensitive material, and then adding Al₂O₃Calcining the ceramic tube at 200 ℃ for 2 hours; then the resistance is measuredA 38 omega nichrome heating coil was passed through the Al₂O₃And finally, welding and packaging the device according to an indirectly heated gas sensitive element to obtain the triethylamine gas sensor based on the MOF derived mesoporous NiO sensitive material.

Example 1:

mesoporous In based on MOF derivation₂O₃The triethylamine gas sensor of the-NiO sensitive material and the preparation method thereof comprise the following steps:

(1) 16mL of DMF (N, N-dimethylformamide) and 16mL of ethylene glycol were mixed, and 1mmol of Ni (NO) was added₃)₂·6H₂Adding O and 1.5mmol of terephthalic acid into the mixture, stirring the mixture for 30 minutes to obtain a uniformly mixed solution, transferring the uniformly mixed solution into a hydrothermal kettle, heating the mixture to react for 6 hours at 150 ℃, cooling the mixture to room temperature after the reaction is finished, centrifuging and cleaning the generated precipitate for multiple times by using ethanol, drying the centrifuged product for 12 hours at 80 ℃ to obtain a Ni-MOF precursor, wherein the mass of the obtained product is 150 mg.

(2) Dissolving 2g of polyvinylpyrrolidone (PVP) in 40mL of ethanol, weighing 200mg of Ni-MOF precursor obtained in the step (1), adding the Ni-MOF precursor into the mixed solution, performing ultrasonic treatment on the obtained mixed solution for 5 minutes, stirring the mixed solution for 25 minutes, standing the mixed solution at room temperature for 12 hours, performing centrifugal cleaning on the generated precipitate for multiple times by using ethanol, and drying the centrifugal product at 80 ℃ for 12 hours to obtain a PVP-Ni-MOF material, wherein the mass of the obtained product is 160 mg.

(3) Adding 30mg of PVP-Ni-MOF obtained In the step (2) and indium nitrate into 10mL of ethanol, wherein the mass of the indium nitrate is 20% of that of the PVP-Ni-MOF, carrying out ultrasonic treatment for 15 minutes, stirring for 15 minutes, reacting for 24 hours at room temperature, carrying out centrifugal cleaning on the generated precipitate for multiple times by using ethanol, and then drying the centrifugal product at 80 ℃ for 12 hours to obtain an In/Ni-MOF precursor, wherein the mass of the obtained product is 26 mg.

(4) Calcining the In/Ni-MOF precursor obtained In the step (3) for 2 hours at 500 ℃ to obtain mesoporous In derived based on MOF₂O₃NiO sensitive material, mass of product obtained 10 mg.

(5) Taking mesoporous In₂O₃The NiO sensitive material and the deionized water are mixed into uniform slurry, a small amount of the slurry is dipped by a brush and evenly coated on the Al₂O₃Forming a sensitive material film with the thickness of 45 mu m on the outer surfaces of the ceramic tube and the gold electrode; al (Al)₂O₃The inner diameter of the ceramic tube is 0.7mm, the outer diameter is 1.25mm, the length is 4.5mm, the width of a single annular gold electrode is 0.45mm, and the distance between two gold electrodes is 0.55 mm; a platinum wire lead is led out of the gold electrode, and the length of the platinum wire lead is 5 mm;

(6) al coated with sensitive material film₂O₃Baking the ceramic tube under an infrared lamp for 10 minutes, and drying the sensitive material, and then adding Al₂O₃Calcining the ceramic tube at 200 ℃ for 2 hours; then, a nickel-chromium heating coil having a resistance value of 38 Ω was passed through Al₂O₃The interior of the ceramic tube is used as a heating wire, and finally the device is welded and packaged according to an indirectly heated gas sensitive element to prepare the mesoporous In derived based on the MOF₂O₃A triethylamine gas sensor of NiO sensitive material.