阅读说明：本技术 一种对no2敏感的具有三维核壳结构的复合气敏材料的制备方法 (For NO2Preparation method of sensitive composite gas-sensitive material with three-dimensional core-shell structure ) 是由 刘丕均 张亚非 邹城 齐燕 余致远 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种对NO2敏感的具有三维核壳结构的复合气敏材料的制备方法,该方法包括以下步骤：(1)使用水热法制备γ-Fe<Sub>2</Sub>O<Sub>3</Sub>微球；(2)在γ-Fe<Sub>2</Sub>O<Sub>3</Sub>微球基础上利用静电自组装法再制备γ-Fe<Sub>2</Sub>O<Sub>3</Sub>@GO三维核壳结构的纳米复合材料；(3)然后对γ-Fe<Sub>2</Sub>O<Sub>3</Sub>@GO进行原位热还原以制备γ-Fe<Sub>2</Sub>O<Sub>3</Sub>@RGO,用于NO<Sub>2</Sub>气敏性能测试。该方法制备具有三维核壳结构的复合气敏材料对NO<Sub>2</Sub>具有很高的灵敏度以及很低的检测极限。本发明操作简便,反应条件简易,可用于大规模的制备器皿传感器元器件,适用于工业化生产。(The invention discloses a preparation method of a composite gas-sensitive material sensitive to NO2 and having a three-dimensional core-shell structure, which comprises the following steps: (1) preparation of gamma-Fe using hydrothermal method 2 O 3 Microspheres; (2) in the presence of gamma-Fe 2 O 3 Gamma-Fe is prepared by utilizing electrostatic self-assembly method on the basis of microspheres 2 O 3 @ GO nano composite material with three-dimensional core-shell structure; (3) then to gamma-Fe 2 O 3 @ GO undergoes in-situ thermal reduction to produce gamma-Fe 2 O 3 @ RGO for NO 2 And (5) testing gas-sensitive performance. The method is used for preparing the NO of the composite gas-sensitive material with the three-dimensional core-shell structure 2 Has high sensitivity and low detection limit. The invention has simple and convenient operation and simple reaction condition, and can be used for large plantsThe scale preparation ware sensor component is suitable for industrial production.)

1. A preparation method of a composite gas sensitive material sensitive to NO2 and having a three-dimensional core-shell structure is characterized by comprising the following steps:

step (1) of preparing gamma-Fe by using hydrothermal method₂O₃Microspheres;

step (2) for the prepared gamma-Fe₂O₃The microspheres are modified to make gamma-Fe₂O₃The surface of the microsphere is positively charged;

step (3), mixing GO with gamma-Fe₂O₃The microspheres are compounded to coat GO with gamma-Fe₂O₃Micro-spheres to form gamma-Fe₂O₃@ GO three-dimensional core-shell structures;

step (4) of applying gamma-Fe by a dropping coating method₂O₃The @ GO composite material is uniformly deposited on the gas sensor interdigital electrode substrate;

step (5), for gamma-Fe₂O₃@ GO is subjected to in-situ thermal reduction to obtain gamma-Fe₂O₃@ RGO gas sensor, and for NO₂And (5) carrying out gas-sensitive performance test.

2. The method for preparing the composite gas-sensitive material with the three-dimensional core-shell structure and sensitive to NO2, according to claim 1, wherein the hydrothermal method in the step (1) is performed at a temperature of 200 ℃ for a time of 18 h.

3. The method for preparing the composite gas-sensitive material with the three-dimensional core-shell structure and sensitive to NO2 as claimed in claim 1, wherein the chemical used for the modification in the step (2) is 3-aminopropyltriethoxysilane.

4. The method for preparing the NO2 sensitive composite gas-sensitive material with the three-dimensional core-shell structure according to claim 1, wherein the step (3) of compounding is to use an electrostatic self-assembly method to combine negative GO and modified positive gamma-Fe₂O₃And (4) compounding the microspheres.

5. The method for preparing the NO2 sensitive composite gas sensitive material with the three-dimensional core-shell structure according to claim 1, wherein the dripping method in the step (4) is a magnetic field assisted dripping method by gamma-Fe₂O₃The magnetic property of the microsphere forms a uniform sensing film when being dripped.

6. The method for preparing a composite gas-sensitive material sensitive to NO2 and having a three-dimensional core-shell structure as claimed in claim 1, wherein the in-situ thermal reduction in step (5) is carried out by treating the interdigital electrode at 200 ℃ to enhance γ -Fe₂O₃The connectivity of @ RGO to the interdigitated electrodes.

Technical Field

The invention relates to a method for preparing a gas sensitive material on a sensor component, in particular to a method for preparing a composite gas sensitive material which is sensitive to NO2 and has a three-dimensional core-shell structure.

Background

A gas sensor is a sensor used to detect the composition and content of a gas. A gas sensor is generally considered to be a transducer that converts a certain gas volume fraction into a corresponding electrical signal.

Sensing technology is one of the most rapidly developing high and new technologies in the world today. Since the end of the last 70 s, the research and development work of sensors has been widely emphasized by countries in the world due to the rapid development of electronic computer technology and artificial intelligence, and the protection of natural ecological environment. In recent years, with the rapid development of the scientific and technological level and the industrialization process, the leakage and the overproof emission of various toxic and harmful gases become very common. This not only has an adverse effect on the health of humans or animals, but also endangers the surrounding ecological environment, causing irreparable damage. In order to protect the ecological environment and personal safety, gas detection is increasingly widely applied in the fields of traditional industries such as earthquake prediction, mine safety, oil exploration, medical health, pollution source detection, chemical process control, metallurgy and the like, and even all the fields of the subject of the new technology revolution, such as bioscience, microelectronics, novel materials and the like. Most attention is paid to the fact that as the scale of industrial production is gradually enlarged, the kinds of products are gradually increased, and the kinds and amounts of gas raw materials used in production and gases generated during the production are also increased, such as acetone, liquefied petroleum gas, city gas, natural gas, nitrogen dioxide (NO)₂) Etc. [2-3 ]]. Some of these gases are flammable and explosive, and some are toxic and harmful, and once they are released into the air, they can seriously pollute the environment and cause explosion, fire and potential danger of poisoning people. In order to ensure safety, it is necessary to detect and quantitatively analyze various gases in advance.

Therefore, the development of gas sensor technology is increasingly demanded, and the research and development of gas sensors are particularly important.

Disclosure of Invention

The purpose of the invention is as follows: the preparation method of the composite gas sensitive material sensitive to NO2 and provided with the three-dimensional core-shell structure is provided to solve the problems involved in the background technology.

The technical scheme is as follows: a preparation method of a composite gas sensitive material sensitive to NO2 and having a three-dimensional core-shell structure comprises the following steps:

step (1) of preparing gamma-Fe by using hydrothermal method₂O₃Microspheres;

step (2) for the prepared gamma-Fe₂O₃The microspheres are modified to make gamma-Fe₂O₃The surface of the microsphere is positively charged;

step (3), mixing GO with gamma-Fe₂O₃The microspheres are compounded to coat GO with gamma-Fe₂O₃Micro-spheres to form gamma-Fe₂O₃@ GO three-dimensional core-shell structures;

step (4) of applying gamma-Fe by a dropping coating method₂O₃The @ GO composite material is uniformly deposited on the gas sensor interdigital electrode substrate;

step (5), for gamma-Fe₂O₃@ GO is subjected to in-situ thermal reduction to obtain gamma-Fe₂O₃@ RGO gas sensor, and for NO₂And (5) carrying out gas-sensitive performance test.

In a further embodiment, the hydrothermal process of step (1) is carried out at a temperature of 200 ℃ for a period of 18 h.

In a further embodiment, the chemical used for the modification described in step (2) is 3-aminopropyltriethoxysilane.

In a further embodiment, the step (3) of compounding is to use an electrostatic self-assembly method to combine the self-negatively-charged GO with the modified positively-charged gamma-Fe₂O₃And (4) compounding the microspheres.

In a further embodiment, the dispensing process of step (4) is a magnetic field assisted dispensing process with gamma-Fe₂O₃The magnetic property of the microsphere forms a uniform sensing film when being dripped.

In a further embodiment, the in-situ thermal reduction in step (5) is carried out by treating the interdigital electrodes together at 200 ℃ to enhance gamma-Fe₂O₃The connectivity of @ RGO to the interdigitated electrodes.

Has the advantages that: the invention relates to a preparation method of a composite gas sensitive material with a three-dimensional core-shell structure and sensitive to NO2, which adopts an electrostatic self-assembly method to prepare GO and gamma-Fe₂O₃The microspheres are compounded together to form a heterojunction, so that the NO of a single material is greatly improved₂The sensitivity of (2). Mixing GO and gamma-Fe₂O₃The microspheres are compounded together by an electrostatic self-assembly method to prepare the NO gas sensor pair₂Has great sensitivity and low detection limit. The higher the test temperature, the lower the detection limit and the higher the sensitivity. The invention has simple operation, simple reaction condition and low price of the electrostatic self-assembly method, can be used for preparing the ware sensor element in a large scale and is suitable for industrialized production.

Drawings

FIG. 1 shows γ -Fe prepared in example 1 of the present invention₂O₃Microspheres and gamma-Fe₂O₃@ GO SEM image of three-dimensional core-shell structure; wherein the diagram (a) is gamma-Fe₂O₃SEM image of the microspheres, and figure b is gamma-Fe₂O₃@ GO SEM image of three-dimensional core-shell structure.

FIG. 2 shows the deposition of gamma-Fe in example 1 of the present invention₂O₃Microspheres and gamma-Fe₂O₃The thermogravimetric regression analysis chart of the @ GO three-dimensional core-shell structure.

FIG. 3 shows the gas sensor for different concentrations of NO in example 1 of the present invention₂The sensitivity map of (c).

Detailed Description

Generally, an ideal gas sensor should have the following characteristics: (1) the response speed is high, and is generally required to be less than 50s (including two processes of gas adsorption and desorption), and ideally is less than 10 s; (2) the sensitivity is high, and only the high sensitivity can be sensitive to the concentration of a tiny amount of gas; (3) high selectivity, sensitivity to a specific gas only and insensitivity to other gases; (4) reversibility, repeated sensitivity, that is, sensitivity which is not disposable and can be used for a plurality of times for a long time; (5) the service life is long, and generally more than half a year or one year is required; (6) small volume, convenient installation and carrying.

The physical interface between two different materials is commonly referred to as a heterojunction, while materials that combine the two different compositions have a heterostructure. The conductivity type of both sides of the junction is controlled by doping, and the same type of doping is called homoheterojunction (n-n, p-p), and the different type of doping is called heteroheterojunction (n-p, p-n). The homotype heterojunction is a majority carrier device, has higher speed than a minority carrier device, and is suitable for being used as a gas sensor.

The electrostatic self-assembly method has the advantages of simple equipment, low price, suitability for mass molding and the like, and is widely applied to industrial production at present.

The sensor has wide measuring range, high precision and good input and output linearity in the application process; the function is complete, the use is convenient, and the device can be used for measurement and protection of a common system; the volume is small, the weight is light, no pollution is caused, the interference resistance is realized, and the environment-friendly characteristic is excellent.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.