阅读说明：本技术 一种利用纳米纤维素进行低温水热反应制备氧化锡及so2气敏传感器的方法 (Preparation of tin oxide and SO by low-temperature hydrothermal reaction of nano-cellulose2Method for gas sensor ) 是由 何星欣 应智花 李丽丽 汶飞 郑鹏 王高峰 于 2021-06-30 设计创作，主要内容包括：本发明公开一种利用纳米纤维素进行低温水热反应制备氧化锡及SO-(2)气敏传感器的方法,属于气体传感器领域。该SO-(2)气体传感器以纳米纤维素、五水四氯化锡为原料,通过低温水热合成得到氧化锡材料。随后将该材料配成悬浊液通过喷涂法均匀地喷涂在叉指电极上,形成一层气敏薄膜,从而得到SO-(2)气体传感器。该制备方法简单、环保,且得到的传感器能够检测低浓度的SO-(2)。(The invention discloses a method for preparing tin oxide and SO by using nanocellulose to carry out low-temperature hydrothermal reaction 2 A method of a gas sensor belongs to the field of gas sensors. The SO 2 The gas sensor takes nano-cellulose and stannic chloride pentahydrate as raw materials, and the stannic oxide material is obtained through low-temperature hydrothermal synthesis. Then preparing the material into suspension, and uniformly spraying the suspension on the interdigital electrode by a spraying method to form a layer of gas-sensitive film, thereby obtaining SO 2 A gas sensor. The preparation method is simple and environment-friendly, and the obtained sensor can detect low-concentration SO 2 。)

1. A method for preparing tin oxide by utilizing nanocellulose to carry out low-temperature hydrothermal reaction is characterized by comprising the following preparation processes:

adding a certain mass of nano-cellulose solution into a solution, wherein the solution is prepared by dissolving stannic chloride pentahydrate in deionized water; and (3) uniformly stirring the mixed solution, carrying out low-temperature hydrothermal reaction, and after the reaction is finished, carrying out centrifugation, washing, drying and calcining treatment to obtain the tin oxide material.

2. Preparation of SO by using nanocellulose to carry out low-temperature hydrothermal reaction₂A method of making a gas sensor, comprising the steps of:

step 1: preparing a tin oxide material, wherein the preparation process comprises the following steps:

adding a certain mass of nano-cellulose solution into a solution, wherein the solution is prepared by dissolving stannic chloride pentahydrate in deionized water; uniformly stirring the mixed solution, carrying out low-temperature hydrothermal reaction, and after the reaction is finished, carrying out centrifugation, washing, drying and calcining treatment to obtain a tin oxide material;

step 2: preparation of SO₂The gas sensor is prepared by the following steps:

adding deionized water into the tin oxide material obtained in the step 1, performing ultrasonic treatment to obtain uniformly dispersed suspension, transferring the suspension into a spray pen container through a liquid transfer gun, uniformly spraying the suspension on the surface of the interdigital electrode, and drying to obtain SO₂A gas sensor.

3. SO prepared by low-temperature hydrothermal reaction of nano-cellulose according to claim 2₂The method for preparing the gas sensor is characterized in that the mixture ratio of the mixed solution in the step 1 is any one of the following:

the stannic chloride pentahydrate is 209.32mg and 30mg of nano-cellulose solution;

or, the stannic chloride pentahydrate is 209.32mg and 40mg nanocellulose solution;

or, the stannic chloride pentahydrate is 209.32mg and 50mg nanocellulose solution;

alternatively, the stannic chloride pentahydrate is 209.32mg and 60mg nanocellulose solution.

4. The method for preparing SO according to claim 2, wherein the nano-cellulose is used for carrying out low-temperature hydrothermal reaction₂The method of the gas sensor is characterized in that in the step 1, the added nano-cellulose solution is CNF.

5. The method for preparing SO according to claim 2, wherein the nano-cellulose is used for carrying out low-temperature hydrothermal reaction₂The method of the gas sensor is characterized in that in the step 1, the condition of the low-temperature hydrothermal reaction is 60 ℃/2 h; centrifuging at 8000rpm for 10 min; drying at 60 deg.C for 24 h.

6. The method for preparing SO according to claim 2, wherein the nano-cellulose is used for carrying out low-temperature hydrothermal reaction₂The method for preparing the gas sensor is characterized in that in the step 1, the mixed solution is subjected to low-temperature hydrothermal reaction, and after the reaction is finished, a tin oxide precursor (Sn (OH)) is obtained through centrifugation, washing and drying treatment₄) And finally calcining at the high temperature of 600 ℃ for 2 hours to obtain the tin oxide nano material.

7. The method for preparing SO according to claim 2, wherein the nano-cellulose is used for carrying out low-temperature hydrothermal reaction₂The method for preparing the gas sensor is characterized in that in the step 2, the mass of tin oxide in the suspension is 10 mg/ml.

8. The method for preparing SO according to claim 2, wherein the nano-cellulose is used for carrying out low-temperature hydrothermal reaction₂The method for the gas sensor is characterized in that in the step 2, the interdigital electrode is cleaned firstly, and the cleaning step is as follows:

(1) carrying out ultrasonic treatment for 3-5 minutes by using acetone;

(2) ultrasonically cleaning the glass substrate for 3-5 minutes by using absolute ethyl alcohol;

(3) ultrasonically cleaning for 3-5 minutes by using deionized water;

(4) and drying the surface of the interdigital electrode by using nitrogen.

9. The method for preparing SO according to claim 2, wherein the nano-cellulose is used for carrying out low-temperature hydrothermal reaction₂The method of the gas sensor is characterized in that in step 2, the inter-finger width of the interdigital electrode is 50 μm.

10. The method for preparing SO according to claim 2, wherein the nano-cellulose is used for carrying out low-temperature hydrothermal reaction₂The method of the gas sensor is characterized in that in the step 2, when a spraying method is used, the air pressure of a spray pen is 0.01 MPa-0.03 MPa; and drying the sprayed sensor for 5 hours at 60 ℃.

Technical Field

The invention relates to the field of gas sensors, in particular to a sensor utilizing nanocelluloseSynthesis method for preparing tin oxide by low-temperature hydrothermal reaction and application of synthesis method in SO₂Application in gas sensors. Detecting SO according to resistance change of sensor of tin oxide prepared from nano-cellulose under ultraviolet light₂A gas.

Background

SO₂Is a typical polluted environment gas. Since coal and petroleum generally contain sulfur, SO is formed during combustion₂。SO₂Can be oxidized into SO₃And the acid rain reacts with rainwater to form acid rain, so that the health of aquatic ecosystems and land ecosystems is greatly damaged. In addition, it is a toxic gas, which is tolerated by humans at about 5ppm, and has a long-term exposure limit of 2ppm, since it can cause serious diseases in humans, such as respiratory and cardiovascular diseases and lung cancer. Therefore, real-time continuous detection of SO2 gas is important, especially for detecting low concentration SO₂。

The metal oxide semiconductor is considered as the most promising gas sensitive material, and plays a crucial role in monitoring toxic and harmful gases due to the advantages of simple manufacture, low cost and the like. However, the semiconductor sensor also has problems such as complicated operating equipment, high reaction temperature, long time, high detection concentration, and low response value. Therefore, a sensor having simple operation, low requirement for use conditions, and high sensitivity is required.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a method for preparing tin oxide and SO by using nanocellulose to carry out low-temperature hydrothermal reaction₂Method for gas sensor, measurement under ultraviolet light for effective detection of SO₂Gas, simultaneously reduces the use temperature of equipment, has complex operation and the like.

In order to solve the technical problems in the prior art, the scheme of the invention is as follows:

a method for preparing tin oxide by utilizing nanocellulose to carry out low-temperature hydrothermal reaction comprises the following preparation processes:

adding a certain mass of nano-cellulose solution into a solution, wherein the solution is prepared by dissolving stannic chloride pentahydrate in deionized water; and (3) uniformly stirring the mixed solution, carrying out low-temperature hydrothermal reaction, and after the reaction is finished, carrying out centrifugation, washing, drying and calcining treatment to obtain the tin oxide material.

The invention also discloses a method for preparing tin oxide by using nanocellulose to carry out low-temperature hydrothermal reaction and applying the tin oxide to SO₂A gas sensor comprising the steps of:

step 1: the preparation method of the tin oxide gas-sensitive material comprises the following steps:

209.32mg of stannic chloride pentahydrate is added into nano-cellulose solutions with different mass, deionized water is added to ensure that the solution is 10ml, the solution is stirred uniformly, the hydrothermal reaction is carried out at low temperature, and after the reaction is finished, the solution is centrifuged, washed and dried to obtain a stannic oxide precursor (Sn (OH)₄) And finally, performing high-temperature calcination at 600 ℃/2h to obtain the tin oxide nano material.

Step 2: preparation of SO₂Adding a proper amount of water into the tin oxide material obtained in the step 1, performing ultrasonic dispersion to obtain uniformly dispersed tin oxide suspension, transferring the suspension into a container of a spray pen through a liquid transfer gun, uniformly spraying the suspension on an interdigital electrode by using a spraying method, and drying to prepare SO₂A gas sensor.

Based on the above scheme, the nanocellulose is preferably CNF ((the raw material is filter paper, prepared by a chemical mechanical method, and the cellulose is macromolecular polysaccharide composed of D-glucose with beta-1, 4 glycosidic bonds).

On the basis of the above scheme, it is preferable that the tin tetrachloride pentahydrate in the step 1 is 209.32 mg; the nanocellulose solution was 30mg (3 ml).

The amount of the stannic chloride pentahydrate is 209.32 mg; the nanocellulose solution was 40mg (4 ml).

The amount of the stannic chloride pentahydrate is 209.32 mg; the nanocellulose solution was 50mg (5 ml).

The amount of the stannic chloride pentahydrate is 209.32 mg; the nanocellulose solution was 60mg (6 ml).

On the basis of the above scheme, preferably, the magnetic stirring time is 60 min.

On the basis of the scheme, the low-temperature hydrothermal condition is preferably that the reaction is carried out for 2 hours at 60 ℃ in a polytetrafluoroethylene reaction kettle.

On the basis of the above scheme, preferably, the centrifugation condition is 8000rpm for 10 minutes.

On the basis of the scheme, preferably, the washing and drying conditions are that deionized water and absolute ethyl alcohol are alternately washed and centrifuged for 3 times, and finally the obtained precipitate is dried for 24 hours at the temperature of 60 ℃.

On the basis of the above scheme, preferably, the high-temperature calcination condition is 4 ℃/min rising to 600 ℃ and keeping for 2 h.

On the basis of the scheme, preferably, the concentration of tin oxide in the suspension in the step 2 is 10mg/ml, and ultrasonic treatment is carried out for 30-50 min.

In addition to the above embodiments, the air pressure of the air brush is preferably 0.01 to 0.03 MPa.

Based on the above scheme, it is preferable that the inter-finger distance of the inter-finger electrode in step 2 is 50 μm.

On the basis of the scheme, preferably, the sensor is dried for 5 hours at 60 ℃ in the step 2.

Compared with the prior art, the technical scheme of the invention is as follows:

(1) the method prepares the tin oxide by the nano-cellulose, has the hydrothermal reaction temperature of 60 ℃, has short time of only 2 hours, and is green and environment-friendly. In the traditional scheme for preparing tin oxide by hydrothermal method, sodium citrate is generally needed for reduction or sodium hydroxide is needed for forming precipitate, other medicines are needed to be added, multiple medicines are needed, the reaction temperature is 160-200 ℃, the addition is not needed, and the prepared tin oxide has good effect.

(2) The invention prepares tin oxide by nano-cellulose and uses the tin oxide as SO₂The gas sensor can detect low-concentration SO₂. The nanometer size effect of the nanometer cellulose can prepare the tin oxide nanometer material. In addition, the tin oxide nano material prepared from the nano cellulose has higher surface activity and stronger adsorbability, and is beneficial to monitoring low-concentration SO₂。

Drawings

FIG. 1 shows that the invention utilizes nano-cellulose to carry out low-temperature hydrothermal reaction to prepare tin oxide and apply the tin oxide to SO₂Method of gas sensor TG/DTG analysis of tin oxide prepared in the examples was carried out.

FIG. 2 shows that the invention utilizes nano-cellulose to perform low-temperature hydrothermal reaction to prepare tin oxide and apply the tin oxide to SO₂Method of gas sensor XRD analysis of tin oxide prepared in the examples.

FIG. 3 shows that the present invention utilizes nanocellulose to perform a low-temperature hydrothermal reaction to prepare tin oxide and apply the tin oxide to SO₂Method of gas sensor the electron microscope scan of the tin oxide prepared in the examples was carried out.

FIG. 4 shows that the present invention utilizes nanocellulose to perform a low-temperature hydrothermal reaction to prepare tin oxide and apply the tin oxide to SO₂Method for gas sensor implementation examples tin oxide materials prepared from nanocellulose of different masses were treated for different concentrations (250, 500, 750, 1000, 1250ppb) of SO₂Gas response recovery test plots.

FIG. 5 shows that the present invention utilizes nanocellulose to perform a low-temperature hydrothermal reaction to prepare tin oxide and apply the tin oxide to SO₂Method of gas sensor the gas-sensitive properties of the tin oxide materials prepared in the examples were carried out.

Wherein (a) SnO₂/50mg CNF sensor in SO₂A repeatability test chart at a gas concentration of 1000ppb, and (b) SnO₂/50mg CNF sensor in SO₂Stability test chart at gas concentration of 1000ppb (c) SnO₂/50mg CNF sensor in SO₂Response plot with increasing concentration (RH ═ 9.4% to 73.9%) at a gas concentration of 1000 ppb.

Detailed Description

The invention will be elucidated below with reference to the drawings and an embodiment example, from which the invention will be better understood.

Examples

Synthesis method for preparing tin oxide by taking tin tetrachloride pentahydrate as tin source and performing low-temperature hydrothermal reaction on nanocellulose and application of synthesis method in SO₂Use in gas sensorsThe method comprises the following steps:

step 1: preparing a tin oxide nano material; the preparation process comprises the following steps:

adding a proper amount of nano cellulose solution into 209.32mg of stannic chloride pentahydrate dropwise, adding deionized water dropwise to ensure that the total volume of the four components is 10ml, magnetically stirring for 30min, placing the solution in a polytetrafluoroethylene reaction kettle, carrying out hydrothermal treatment at a low temperature of 60 ℃ for 2h, carrying out centrifugal drying on the obtained precipitate to obtain a stannic oxide precursor, and finally carrying out high-temperature calcination (600 ℃/2h) to obtain stannic oxide nano material powder.

Step 2: preparation of SO₂A gas sensor; the preparation process comprises the following steps:

mixing 10mg of the tin oxide material obtained in the step 1 in 1ml of deionized water, performing ultrasonic dispersion for 30min to obtain uniformly dispersed tin oxide suspension, transferring the suspension into a container of a spray pen through a liquid transfer gun, uniformly spraying the suspension on a clean interdigital electrode by using a spraying method, and drying to prepare SO₂A gas sensor. Obtained SO₂And the gas sensor performs gas-sensitive performance test under ultraviolet.

In this example, as shown in fig. 1, TG/DTG of tin oxide nanomaterial has a slight mass loss at a temperature of 41.97 ℃, which is caused by desorption of water from the precursor, and a large mass loss occurs in a range of 41.97 to 381.25 ℃, and CNF and crystal water are desorbed from the sample. In the whole process, the steel is always in a weightless state until the steel is stable at about 600 ℃.

In this example, the XRD pattern of the tin oxide nanomaterial is shown in fig. 2, and it can be seen that the diffraction peaks of the four components can all correspond to PDF, which indicates that the prepared product is tin oxide.

In this example, the XRD patterns of the tin oxide nano-materials are shown in fig. 3, and it can be seen that the sizes of the tin oxide are all less than 100 nm.

In this example, SO₂The recovery test of the response of the gas sensor to the bodies with different concentrations (250, 500, 750, 1000, 1250ppb) is shown in fig. 4, and it can be seen that the response of the four components increases with the increase of the gas concentration, and the response value of tin oxide prepared by 50mg CNF is the most excellentHigh, next 60mg of tin oxide prepared by CNF, 40mg of tin oxide prepared by CNF, and finally 30mg of tin oxide prepared by CNF.

In this example, SnO₂/50mg CNF sensor in SO₂The reproducibility at a gas concentration of 1000ppb is shown in fig. 5 a, which shows that the reproducibility of the sensor is better.

In this example, SnO₂/50mg CNF sensor in SO₂Stability at a gas concentration of 1000ppb as shown in b of fig. 5, it can be seen that the sensor has good stability without a great change in response value within one month.

In this example, SnO₂/50mg CNF sensor in SO₂The response of the gas concentration of 1000ppb at different humidities is shown in fig. 5 c, and it can be seen that the response of the sensor is slightly decreased with the increase of the humidity, but the detection of the gas sensitivity is not greatly affected.

The principal features and advantages of the invention have been shown and described.

The above embodiments are illustrative and not restrictive, and several embodiments may be enumerated without departing from the scope of the present invention, and therefore, changes and modifications may be made without departing from the spirit of the present invention.