Preparation method and application of semiconductor metal oxide modified by rare earth element
By modifying semiconductor metal oxides by rare earth elements, gas sensing materials with hollow nano microsphere structures were prepared, which solved the problems of poor selectivity and low sensitivity of gas sensors in the prior art, and achieved efficient detection of trace ethanolamine.
Patent Information
- Application Number
- CN202311258274.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-26
- Publication Date
- 2025-03-28
AI Technical Summary
Existing semiconductor metal oxide gas sensors have problems such as high operating temperature, poor selectivity and low sensitivity, making it difficult to effectively detect trace amounts of ethanolamine.
By modifying semiconductor metal oxides by rare earth elements, gas sensing materials with hollow nano microsphere structure and large specific surface area were prepared, and their unique microstructure and electronic structure regulation were used to improve gas sensing response capabilities.
It realizes rapid, sensitive and highly selective detection of trace ethanolamine, reduces detection temperature, enhances the environmental humidity resistance of the sensor, and has the potential for commercial application.
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Figure CN119706964A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a preparation method and application of a semiconductor metal oxide modified by a rare earth element, and belongs to the technical field of nano-functional materials and environmental monitoring. Background Art
[0002] As one of the common volatile organic compounds (VOCs), ethanolamine is an important fine organic chemical raw material, which is commonly used in various links of industrial production. From the structure of ethanolamine, there are both N atoms and -OH groups, and it has the chemical properties of both amines and alcohols. Therefore, ethanolamine is widely used, including textiles, daily chemicals, cleaning, medicine and pesticides, rubber, polyurethane, etc.
[0003] However, this organic compound is harmful to the human body. Since ethanolamine is slightly corrosive, it will cause a certain degree of irritation after skin contact or inhalation, causing severe skin burns and eye burns. Inhalation may cause respiratory irritation, bronchitis, spasm, etc. Therefore, it is very necessary to detect ethanolamine in production and life.
[0004] Sensing technology is an important technical means to realize information perception and collection, and it is also a link between the upper and lower parts of the "IOT" system. In the rich and complex sensor system, gas sensors have shown important application value and wide application demand in many fields such as environmental protection, food safety, agricultural production, medical health, national defense security, etc. Especially in the 21st century when science and technology are developing steadily, people have higher and higher requirements for their own safety and the quality of the surrounding environment. The combustion of fossil fuels such as coal and oil, the leakage of various waste gases in industrial production and manufacturing processes, and the release of harmful gases in indoor furniture and building materials in daily life not only pollute the environment but also endanger human health. Therefore, it is urgent to develop gas sensing technology and develop gas sensing equipment to effectively and in real time monitor gases that threaten the human environment and health.
[0005] The core of gas sensors is the design and preparation of gas-sensitive materials. Metal oxide semiconductor nanostructures have attracted extensive attention from researchers due to their low cost, simple preparation method, and high detection sensitivity. However, there are some problems with single metal oxides, such as low stability, poor selectivity, and high operating temperature. These problems limit the application of semiconductor oxide gas sensors. Therefore, in order to improve the performance of semiconductor metal oxide gas sensors, the modification of metal oxides is very important.
[0006] Rare earth elements have rich gradient energy levels. Modifying the surface of metal oxides with rare earth elements can achieve the modification of the energy band structure of the original metal oxides. Rare earth elements are introduced into metal oxides as impurity energy levels to achieve the regulation of the "d band center" of the original metal oxides and enhance their accessibility to target gas molecules.
[0007] The mechanism of semiconductor resistance gas sensor to detect target gas molecules is to change the resistance of the sensor by the reaction between the absorbed target gas molecules and the chemically adsorbed oxygen species on the surface of the sensing material, and detect the concentration of the target gas by the change of resistance under the condition of the target gas. The determination of the gas concentration is achieved by establishing the relationship between the gas concentration and the change of the resistance value. Summary of the invention
[0008] At present, single semiconductor metal oxides have disadvantages such as high operating temperature, poor selectivity, and low sensitivity. Therefore, it is necessary to modify the original semiconductor metal oxides to improve the performance of gas sensors. The improvement of the gas sensing performance of semiconductor metal oxides is mainly divided into two aspects: the first is the design of its microscopic morphology, and the second is the regulation of its surface electronic structure.
[0009] The gas sensing performance of semiconductor metal oxides is closely related to size, structure and morphology. Nano / micro structures with outstanding porosity and adjustable large surface-to-volume ratio can greatly improve the performance of sensors. In addition, designing the material morphology based on the pore structure is conducive to further improving the material's adsorption capacity for target gas molecules, thereby ultimately improving the gas sensing response.
[0010] In addition, surface electronic regulation of metal oxide semiconductor materials is conducive to further improving the gas sensing response ability of the material. Heteroatom modification is a powerful means to improve gas sensing performance. The introduction of heteroatoms can change the original state of the material surface and can achieve selective adsorption of different target gas molecules. More importantly, the introduction of heteroatoms can form abundant oxygen vacancies on the surface of the material. The presence of vacancies is conducive to the adsorption of target gas molecules by the material to achieve improved gas sensing performance. In summary, the microscopic morphology and structural design of semiconductor metal oxides and the optimization of their surface electronic structure have achieved mutual synergy, which is the key to improving the performance of gas sensors.
[0011] The purpose of the present invention is to provide a method for preparing a rare earth element-modified semiconductor metal oxide gas sensing material with low cost and simple operation, and to use the metal oxide in a gas sensor to achieve rapid and sensitive detection of trace ethanolamine in production and life.
[0012] Based on this purpose, the present invention first prepares a new type of rare earth element modified semiconductor metal oxide gas sensing material, and utilizes the unique hollow nano-microsphere structure, large specific surface area and chemical sensitization and electronic sensitization brought by rare earth element modification of the material to realize the detection of trace ethanolamine gas.
[0013] According to one aspect of the present application, a method for preparing a semiconductor metal oxide modified with a rare earth element is provided, wherein the preparation method comprises:
[0014] In a closed reactor, a mixture containing a nickel precursor, a rare earth element precursor, isopropanol and glycerol is reacted, dried and calcined to obtain the rare earth element-modified semiconductor metal oxide.
[0015] Optionally, the nickel precursor is selected from at least one of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate.
[0016] Optionally, the rare earth element precursor is selected from at least one of a La precursor, a Ce precursor, a Pr precursor, a Y precursor, and a Tb precursor.
[0017] Optionally, the La precursor is selected from at least one of lanthanum sulfate, lanthanum chloride, lanthanum nitrate, lanthanum acetate, and organic lanthanum compounds.
[0018] Optionally, the Ce precursor is selected from at least one of cerium sulfate, cerium chloride, cerium nitrate, cerium acetate, and an organic cerium compound.
[0019] Optionally, the Pr precursor is selected from at least one of praseodymium sulfate, praseodymium chloride, praseodymium nitrate, praseodymium acetate, and organic praseodymium compounds.
[0020] Optionally, the Y precursor is selected from at least one of yttrium sulfate, yttrium chloride, yttrium nitrate, yttrium acetate, and an organic yttrium compound.
[0021] Optionally, the Tb precursor is selected from at least one of terbium sulfate, terbium chloride, terbium nitrate, terbium acetate, and an organic terbium compound.
[0022] Optionally, the mass ratio of the nickel precursor to the rare earth element precursor is 1-2 g: 0.02-0.1 g;
[0023] The mass of the nickel precursor is calculated by its own mass, and the mass of the rare earth element precursor is calculated by its own mass.
[0024] Optionally, the mass volume ratio of the nickel precursor, isopropanol and glycerol is 0.5-1 g: 30-70 mL: 5-10 mL.
[0025] Optionally, the reaction further includes centrifugation, and the number of centrifugation is 3 to 7 times.
[0026] Optionally, the reaction further includes washing the material, and the solvent is selected from at least one of water, ethanol and methanol.
[0027] Optionally, the reaction temperature is 140-200° C., and the reaction time is 12-24 hours.
[0028] Optionally, the reaction temperature is selected from any value of 140°C, 160°C, 170°C, 180°C, 190°C, 200°C or a range between any two of the above points.
[0029] Optionally, the reaction time is selected from any value among 12h, 16h, 20h, 24h or a range between any two of the above points.
[0030] Optionally, the drying temperature is 40 to 90° C., and the drying time is 12 to 24 hours.
[0031] Optionally, the drying temperature is selected from any value of 40°C, 60°C, 70°C, 80°C, 90°C or a range between any two of the above points.
[0032] Optionally, the drying time is selected from any value among 12h, 16h, 20h, 24h or a range between any two of the above points.
[0033] Optionally, the calcination temperature is 300-500° C., and the calcination time is 1-3 hours.
[0034] According to another aspect of the present application, there is provided a rare earth element modified semiconductor metal oxide prepared by the above-mentioned preparation method, wherein the rare earth element modified semiconductor metal oxide is a hollow nano-microsphere;
[0035] The semiconductor metal oxide in the rare earth element modified semiconductor metal oxide is NiO.
[0036] Optionally, the modification amount of the rare earth element in the rare earth element modified semiconductor metal oxide is 1wt% to 3wt%.
[0037] According to another aspect of the present application, there is provided a use of the above-mentioned rare earth element modified semiconductor metal oxide in an ethanolamine gas sensor.
[0038] Optionally, the detection limit of the ethanolamine gas sensor for ethanolamine is 450-500 ppb.
[0039] Optionally, the detection limit of the ethanolamine gas sensor for ethanolamine is any value among 450ppb, 455ppb, 460ppb, 470ppb, 500ppb, or a range value between any two of the above points.
[0040] Optionally, the operating temperature of the ethanolamine gas sensor is 100-160°C.
[0041] Optionally, the ethanolamine gas sensor has better selectivity for ethanolamine.
[0042] In this application, the preparation of NiO hollow nanospheres:
[0043] In this invention, we adopt a two-step method to prepare NiO hollow nanospheres. First, we synthesize NiO-gly structure using glycerate as a template, and then achieve the transformation of glycerate to metal oxide through a one-step calcination.
[0044] 1) First, a certain amount of Ni precursor is dissolved in 60 mL of isopropanol, and then 7 mL of glycerol is added to the above solution. Subsequently, the mixed solution is stirred until a uniform and transparent solution is obtained. After that, 5 mL of deionized (DI) water is added to the above solution under magnetic stirring. Finally, the mixed solution is continuously stirred to obtain a uniform system. The mixed solution is transferred to a 100 mL Teflon-lined stainless steel reactor. At a certain temperature, react, and when the reactor is cooled to room temperature, the precipitate is collected by a centrifuge and then washed several times with a polar solvent. The obtained product is dried in a vacuum drying oven to obtain the final product.
[0045] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined in a muffle furnace, and cooled to room temperature to obtain NiO hollow nanospheres.
[0046] As a specific implementation, the present invention is implemented by the following technical solutions:
[0047] 1. A design and preparation of a semiconductor metal oxide gas sensor based on rare earth element modification. The preparation of the gas sensing material and its application in ethanolamine gas sensing. The preparation method comprises the following preparation steps:
[0048] Step a, preparing a rare earth element modified semiconductor metal oxide gas sensing material;
[0049] Step b, constructing an ethanolamine gas sensor;
[0050] Among them, the specific steps of step a for preparing the rare earth element modified semiconductor metal oxide gas sensing material are:
[0051] 1) First, a certain amount of Ni precursor and rare earth element precursor are dissolved in 60 mL of isopropanol, and then 7 mL of glycerol is added to the above solution. Subsequently, the mixed solution is stirred until a uniform and transparent solution is obtained. After that, 5 mL of deionized (DI) water is added to the above solution under magnetic stirring. Finally, the mixed solution is continuously stirred to obtain a uniform system. The mixed solution is transferred to a 100 mL Teflon-lined stainless steel reactor. At a certain temperature, react, and when the reactor is cooled to room temperature, the precipitate is collected by a centrifuge and then washed several times with a polar solvent. The obtained product is dried in a vacuum drying oven to obtain the final product.
[0052] 2) taking a certain amount of the product obtained in 1) into a crucible, calcining it in a muffle furnace, and cooling it to room temperature to obtain NiO hollow nano-microspheres modified with rare earth elements.
[0053] Step b: The specific construction steps for constructing the ethanolamine gas sensor are:
[0054] (1) Using the interdigital electrode as the gas sensing electrode, add the prepared sample to an appropriate amount of solvent and mix to form a uniform slurry. Evenly drop the slurry on the electrode surface to form a film. Dry the interdigital electrode in an oven to evaporate the solvent to obtain a sensing film.
[0055] (2) The electrode obtained in step (1) is then aged in an oven to remove the organic solvent remaining on the electrode, thereby obtaining a gas sensing electrode with stable resistance. The gas sensing electrode is connected to a test instrument to obtain an ethanolamine gas sensor.
[0056] Optionally, in step (1), the solvent is selected from at least one of ultrapure water, anhydrous ethanol, and acetone.
[0057] 2. The gas sensor based on the two-dimensional metal oxide gas-sensitive material is applied to the detection of ethanolamine gas molecules, and its characteristics are that the specific detection method is:
[0058] (1) Using interdigital electrodes as gas sensing electrodes, 5-10 μL of slurry was dropped onto the surface of the substrate with Ag-Pd printed interdigital electrodes. The electrodes were dried at 65-100°C to form a sensing film.
[0059] (2) The modified interdigital electrode is heated in an oven to 180-200° C. for 12-24 hours to remove the residual organic solvent, thereby obtaining an ethanolamine gas sensor to be tested.
[0060] (3) The gas sensor test is carried out using the static gas distribution method, that is, a certain amount of ethanolamine liquid is evaporated on a hot stage using a micro-injector to obtain a certain concentration of ethanolamine gas. The vaporized ethanolamine gas evaporates in the test chamber, and the ethanolamine gas molecules are detected by recording the resistance change of the sensor before and after the gas is introduced.
[0061] (4) Record the initial resistance of the sensor in air as R a , different concentrations of ethanolamine were introduced into the test chamber, and the resistance when the gas was introduced was recorded as R g , with R g With R a A working curve is drawn based on the relationship between the ratio and the concentration of ethanolamine gas molecules.
[0062] The present invention constructs a series of rare earth element modified NiO hollow nano-microspheres for the first time, and uses them in ultra-sensitive gas sensing detection, realizing the detection of ethanolamine at a relatively low temperature. The constructed sensor has the characteristics of high sensitivity, fast response recovery speed, good selectivity, etc. In addition, due to the introduction of rare earth elements, the sensor has a certain environmental moisture resistance, which greatly enhances its application possibility in the actual environment and provides strong technical support for commercial use. The material presents the characteristics of hollow nano-microspheres and has a porous structure. This unique microstructure increases the specific surface area of the material, is conducive to the mass transfer process of the gas, and is also conducive to the adsorption of gas molecules on the surface of the material. In addition, the modification of rare earth ions effectively realizes the regulation of the electronic structure of the material surface, improves the ability of the material to capture the target gas molecules, and greatly improves the sensor's response to the target gas molecules. The introduction of heteroelements also brings abundant oxygen vacancies to the surface of the substrate material to improve the accessibility of the material to gas molecules. The successful preparation of the material also provides a technical reference for related sensors, such as photoelectrochemical sensors, electrochemical sensors, etc., and has a wide range of potential use value.
[0063] The beneficial effects of this application include:
[0064] 1) The ethanolamine gas sensor provided in the present application is simple to prepare and easy to operate, and can achieve rapid, sensitive, and highly selective detection of ethanolamine gas molecules at a low cost. In addition, the test conditions close to room temperature provide conditions for portable detection of the sensor, and have market development prospects.
[0065] 2) The present application provides a design and preparation of a semiconductor metal oxide gas sensor modified with rare earth elements. The preparation method is simple and uses a "one-pot" hydrothermal synthesis to achieve controllable preparation of the material.
[0066] 3) The thorn-shaped porous microspheres provided in this application provide a new idea for the morphology design of semiconductor metal oxides. BRIEF DESCRIPTION OF THE DRAWINGS
[0067] Figure 1 This is a FE-TEM image of the rare earth element modified semiconductor metal oxide gas sensing material prepared in Example 1 of the present application, with a scale of 500 nm.
[0068] Figure 2 This is a working curve diagram of the gas sensor prepared in Example 11 of the present application.
[0069] Figure 3 This is a selectivity diagram of the gas sensor prepared in Example 12 of the present application. DETAILED DESCRIPTION
[0070] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.
[0071] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.
[0072] In the examples of the present application, the instruments used to characterize the semiconductor metal oxide gas sensing material modified with rare earth elements are as follows:
[0073]
[0074]
[0075] Example 1 Preparation of rare earth element modified semiconductor metal oxide gas sensing material
[0076] 1) First, dissolve 0.5g of nickel sulfate and 0.01g of lanthanum nitrate in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 150°C for 5h. When the reactor is cooled to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol; the obtained product is dried in a vacuum drying oven at 60°C for 5h to obtain the final product.
[0077] 2) Take a certain amount of the product obtained in 1) in a crucible, calcine it in a muffle furnace at 400°C for 3 hours, and cool it to room temperature to obtain NiO hollow nanospheres modified with rare earth elements. Figure 1 It can be seen that the prepared samples have a good hollow nanosphere structure and good dispersibility.
[0078] Example 2 Preparation of rare earth element modified semiconductor metal oxide gas sensing material
[0079] 1) First, dissolve 0.5g of nickel sulfate and 0.01g of cerium nitrate in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 160°C for 6h. When the reactor cools to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol. The obtained product is dried in a vacuum drying oven at 60°C for 7h to obtain the final product.
[0080] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined at 400° C. for 3 h in a muffle furnace, and cooled to room temperature to obtain NiO hollow nanospheres modified with rare earth elements.
[0081] Example 3 Preparation of rare earth element modified semiconductor metal oxide gas sensing material
[0082] 1) First, dissolve 0.75g of nickel chloride and 0.02g of praseodymium nitrate in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 170°C for 6h. When the reactor cools to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol. The obtained product is dried in a vacuum drying oven at 60°C for 7h to obtain the final product.
[0083] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined at 400° C. for 3 h in a muffle furnace, and then cooled to room temperature to obtain NiO hollow nanospheres modified with rare earth elements.
[0084] Example 4 Preparation of rare earth element modified semiconductor metal oxide gas sensing material
[0085] 1) First, dissolve 0.75g of nickel chloride and 0.02g of yttrium nitrate in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 160°C for 6h. When the reactor cools to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol. The obtained product is dried in a vacuum drying oven at 60°C for 7h to obtain the final product.
[0086] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined at 400° C. for 3 h in a muffle furnace, and then cooled to room temperature to obtain NiO hollow nanospheres modified with rare earth elements.
[0087] Example 5 Preparation of rare earth element modified semiconductor metal oxide gas sensing material
[0088] 1) First, dissolve 0.9g of nickel nitrate and 0.03g of terbium nitrate in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 160°C for 6h. When the reactor cools to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol. The obtained product is dried in a vacuum drying oven at 60°C for 7h to obtain the final product.
[0089] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined at 400° C. for 3 h in a muffle furnace, and then cooled to room temperature to obtain NiO hollow nanospheres modified with rare earth elements.
[0090] Example 6
[0091] 1) First, dissolve 0.9g of nickel nitrate and 0.03g of cerium chloride in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 160°C for 6h. When the reactor cools to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol. The obtained product is dried in a vacuum drying oven at 60°C for 7h to obtain the final product.
[0092] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined at 400° C. for 3 h in a muffle furnace, and then cooled to room temperature to obtain NiO hollow nanospheres modified with rare earth elements.
[0093] Example 7
[0094] 1) First, dissolve 1.0g of nickel nitrate and 0.04g of praseodymium chloride in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 160°C for 6h. When the reactor cools to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol. The obtained product is dried in a vacuum drying oven at 60°C for 7h to obtain the final product.
[0095] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined at 400° C. for 3 h in a muffle furnace, and cooled to room temperature to obtain NiO hollow nanospheres modified with rare earth elements.
[0096] Example 8
[0097] 1) First, dissolve 1.0g of nickel acetate and 0.05g of lanthanum chloride in 60mL of isopropanol, and then add 7mL of glycerol to the above solution. Subsequently, stir the mixed solution until a uniform and transparent solution is obtained. After that, add 5mL of deionized (DI) water to the above solution under magnetic stirring. Finally, continue to stir the mixed solution to obtain a uniform system. Transfer the mixed solution to a 100mL Teflon-lined stainless steel reactor. React at 160°C for 6h. When the reactor cools to room temperature, collect the precipitate with a centrifuge and then wash it several times with ethanol. The obtained product is dried in a vacuum drying oven at 60°C for 7h to obtain the final product.
[0098] 2) A certain amount of the product obtained in 1) is placed in a crucible, calcined at 400° C. for 3 h in a muffle furnace, and then cooled to room temperature to obtain NiO hollow nanospheres modified with rare earth elements.
[0099] Example 9 Construction of ethanolamine gas sensor
[0100] (1) Using the interdigital electrode as the gas sensing electrode, the rare earth element modified semiconductor metal oxide gas sensing material prepared in Example 1 was added to an appropriate amount of water and mixed to form a uniform slurry. Then 10 μL of the slurry was dropped on the surface of the substrate with Ag-Pd printed interdigital electrodes. The electrode was dried at 80°C to form a sensing film.
[0101] (2) The electrode obtained in step (1) is then heated to 200° C. in an oven for 5 hours to remove the residual organic solvent, thereby obtaining an ethanolamine gas sensor.
[0102] Example 10 Construction of ethanolamine gas sensor
[0103] (1) Using the interdigital electrode as the gas sensing electrode, the rare earth element modified semiconductor metal oxide gas sensing material prepared in Example 3 was added to an appropriate amount of anhydrous ethanol and mixed to form a uniform slurry. Then 5 μL of the slurry was dropped on the surface of the substrate with Ag-Pd printed interdigital electrodes. The electrode was dried at 60°C to form a sensing film.
[0104] (2) The electrode obtained in step (1) is then heated to 180° C. in an oven for 3 hours to remove the residual organic solvent, thereby obtaining an ethanolamine gas sensor.
[0105] Embodiment 11
[0106] The ethanolamine gas sensors prepared in Examples 9 and 10 are applied to the detection of ethanolamine gas molecules, and the steps are as follows:
[0107] (1) Preparation of gas sensing electrode: The ethanolamine gas sensor constructed in Example 9 was used as the working electrode;
[0108] (2) Preparation of standard gas: To obtain the required gas, ethanolamine liquid was added into the test chamber using a micro syringe and evaporated directly;
[0109] (3) Drawing a working curve: Connect the electrode described in (1) to a gas sensor detection device, and distribute gas in a gas chamber using the method described in (2); test the resistance of the sensor before and after ventilation in a chamber with constant relative humidity and temperature; draw a working curve based on the relationship between the obtained resistance change and the ethanolamine concentration; the resistance change is expressed by R g / R a Indicates that R a refers to the resistance in ambient air, while R g is the resistance in the measured gas; the working curve takes the concentration of ethanolamine gas molecules as the horizontal axis, R g / R a is plotted as the vertical axis. Figure 2 It can be seen that the sensor shows a good linear range for ethanolamine.
[0110] Example 12
[0111] Inject interfering gas molecules with the same concentration as ethanolamine into the chamber, test their gas-sensitive properties, and obtain the selectivity of the sensor. (The test method and test conditions are consistent with those of ethanolamine gas detection); Figure 3 It can be seen that the sensor has good selectivity for ethanolamine molecules.
[0112] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing a rare earth element modified semiconductor metal oxide, characterized in that: The preparation method comprises: In a closed reactor, a mixture containing a nickel precursor, a rare earth element precursor, isopropanol and glycerol is reacted, dried and calcined to obtain the rare earth element-modified semiconductor metal oxide.
2. The preparation method according to claim 1, characterized in that: The nickel precursor is selected from at least one of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate; Preferably, the rare earth element precursor is selected from at least one of a La precursor, a Ce precursor, a Pr precursor, a Y precursor, and a Tb precursor; Preferably, the La precursor is selected from at least one of lanthanum sulfate, lanthanum chloride, lanthanum nitrate, lanthanum acetate, and an organic lanthanum compound; Preferably, the Ce precursor is selected from at least one of cerium sulfate, cerium chloride, cerium nitrate, cerium acetate, and an organic cerium compound; Preferably, the Pr precursor is selected from at least one of praseodymium sulfate, praseodymium chloride, praseodymium nitrate, praseodymium acetate, and organic praseodymium compounds; Preferably, the Y precursor is selected from at least one of yttrium sulfate, yttrium chloride, yttrium nitrate, yttrium acetate, and an organic yttrium compound; Preferably, the Tb precursor is selected from at least one of terbium sulfate, terbium chloride, terbium nitrate, terbium acetate, and an organic terbium compound.
3. The preparation method according to claim 1, characterized in that: The mass ratio of the nickel precursor to the rare earth element precursor is 1-2 g: 0.02-0.1 g; The mass of the nickel precursor is calculated by its own mass, and the mass of the rare earth element precursor is calculated by its own mass.
4. The preparation method according to claim 1, characterized in that: The mass volume ratio of the nickel precursor, isopropanol and glycerol is 0.5-1 g: 30-70 mL: 5-10 mL.
5. The preparation method according to claim 1, characterized in that: The reaction temperature is 140-200°C and the reaction time is 12-24h; Preferably, the drying temperature is 40 to 90° C., and the drying time is 12 to 24 hours.
6. The preparation method according to claim 1, characterized in that: The calcination temperature is 300-500° C., and the calcination time is 1-3 hours.
7. The rare earth element-modified semiconductor metal oxide prepared by the preparation method according to any one of claims 1 to 6, characterized in that: The rare earth element modified semiconductor metal oxide is hollow nano-microspheres; The semiconductor metal oxide in the rare earth element modified semiconductor metal oxide is NiO.
8. The rare earth element modified semiconductor metal oxide according to claim 7, characterized in that: The modification amount of the rare earth element in the rare earth element modified semiconductor metal oxide is 1 wt % to 3 wt %.
9. Use of the rare earth element modified semiconductor metal oxide according to any one of claims 7 to 8 in an ethanolamine gas sensor.
10. The use according to claim 9, characterized in that: The detection limit of the ethanolamine gas sensor for ethanolamine is 450-500 ppb; Preferably, the operating temperature of the ethanolamine gas sensor is 100-160°C.