CN113916946A - N-amyl alcohol gas sensor based on ZnO nano sensitive material and preparation method thereof - Google Patents
N-amyl alcohol gas sensor based on ZnO nano sensitive material and preparation method thereof Download PDFInfo
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- CN113916946A CN113916946A CN202111176364.1A CN202111176364A CN113916946A CN 113916946 A CN113916946 A CN 113916946A CN 202111176364 A CN202111176364 A CN 202111176364A CN 113916946 A CN113916946 A CN 113916946A
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- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
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- G01N27/127—Composition of the body, e.g. the composition of its sensitive layer comprising nanoparticles
Abstract
An n-amyl alcohol gas sensor based on ZnO nano sensitive material and a preparation method thereof belong to the field of semiconductor oxide gas sensors. The sensor is made of Al with two annular, parallel and mutually separated gold electrodes on the outer surface2O3Ceramic tube substrate coated with Al2O3ZnO nano sensitive material on ceramic tube outer surface and gold electrode and Al arranged on the same2O3A nichrome heating coil in the ceramic tube. The ZnO nano sensitive material is prepared by a hydrothermal method, and the ZnO nano flower is composed of porous nano sheets. The invention realizes the adjustment of the content of the oxygen vacancy on the surface of the nano material by changing the temperature rise speed of the nano material during sintering, thereby improving the sensitivity of the sensor to the amyl alcohol. The invention provides a method with lower cost and simpler operation to realize real-time monitoring on the amyl alcohol, and the sensor has simple process and small volume and is suitable for mass production.
Description
Technical Field
The invention belongs to the technical field of semiconductor oxide gas sensors, and particularly relates to an N-pentanol (N-pentanol) gas sensor based on a ZnO nano sensitive material and a preparation method thereof.
Background
N-pentanol is taken as a multi-chain alcohol, is the most promising 'next generation' alcohol fuel, and is widely applied to daily life as a coating solvent, a flotation agent, an antifoaming agent and a medical raw material. However, N-pentanol is a volatile organic compound, has a slight odor, and the vapor thereof is very harmful to human health. The low concentration of n-pentanol can cause irritation to eyes, skin, mucous membranes and upper respiratory tract, and also cause symptoms of headache, cough, nausea, vomiting, etc. Prolonged exposure to high concentrations of N-pentanol can lead to diplopia, deafness, delirium and even methemoglobinemia. Therefore, the method has important significance for detecting N-pentanol.
Among a variety of gas sensors, a resistance-type gas sensor using a semiconductor oxide as a sensitive material has the advantages of high sensitivity, low detection lower limit, good selectivity, high response and recovery speed, simple manufacturing method, low cost and the like, and is one of the most widely used gas sensors at present. With the development of nano science and technology, various methods for improving the gas-sensitive performance of sensors appear, wherein the gas-sensitive performance of nano materials can be improved by increasing active sites.
ZnO is an n-type semiconductor material with a wide forbidden band, and is widely applied to the aspect of gas sensing due to the fact that ZnO is non-toxic and simple in manufacturing method. However, although many ZnO materials with different morphologies and large specific surface area and active site density have been developed, these methods for improving gas sensing performance not only increase experimental difficulty, but also are inconvenient for subsequent popularization and application. Therefore, a simple method is found for further modifying the ZnO material, so that the gas-sensitive property of the ZnO material is improved.
Disclosure of Invention
The invention aims to provide an N-pentanol (N-pentanol) gas sensor based on a ZnO nano sensitive material and a preparation method thereof.
The invention synthesizes ZnO as a sensitive material by a hydrothermal method, and realizes the oxidation of ZnO surface oxygen species (O) by changing the temperature rise speed of the sensitive material during sinteringL、OC、OV) The adjustment of the content improves the reaction efficiency of the gas and the sensitive material, and further improves the sensitivity of the sensor. The sensor with the commercially available tubular structure adopted by the invention has the advantages of simple manufacturing process and small volume, and is beneficial to industrial mass production, thereby having important application value.
The N-pentanol gas sensor based on the ZnO nano sensitive material comprises Al, the outer surface of which is provided with two parallel, annular and mutually separated gold electrodes2O3Ceramic tube substrate coated with Al2O3Sensitive material on the outer surface of the ceramic tube and the gold electrode, Al2O3A nickel-chromium heating coil in the ceramic tube; the method is characterized in that: the sensitive material is a ZnO nano sensitive material, and the oxygen species distribution on the surface of ZnO is optimized by changing the temperature rise speed of sintering, so that the gas-sensitive performance of the ZnO nano sensitive material is improved, and the ZnO nano sensitive material is prepared by the following steps:
(1) adding 0.3-0.35 g of zinc nitrate and 0.3-0.35 g of urea into 35-40 mL of deionized water, and stirring for 60-70 min until the zinc nitrate and the urea are completely dissolved; putting the solution into a 50mL hydrothermal kettle, and reacting for 5-6 h at 140-150 ℃;
(2) and (2) alternately carrying out centrifugal washing on the product obtained in the step (1) by using water and ethanol, wherein the centrifugal speed is 10000-11000 r min-1Centrifuging for 10-12 min;
(3) drying the product centrifugally washed in the step (2) at 80-85 ℃ for 12-13 h;
(4) calcining the dried product obtained in the step (3) at 450-500 ℃ for 1-2 h, wherein the temperature rise speed of the calcination is 4-6 ℃ for min-1Thereby preparing the ZnO nano sensitive material;
the preparation method of the N-pentanol gas sensor based on the ZnO nano sensitive material comprises the following steps:
(1) mixing 1-2 g of ZnO nano sensitive material with 2-3 mL of deionized water, and grinding to form pasty slurry;
(2) then dipping a small amount of slurry to evenly coat Al with two parallel, annular and separated gold electrodes on the outer surface2O3Forming a sensitive material film with the thickness of 20-30 mu m on the surface of the ceramic tube, and enabling the sensitive material to completely cover the annular gold electrode;
(3) coated Al2O3Baking the ceramic tube at 50-100 ℃ for 30-45 minutes, and drying the sensitive material, and then, adding Al2O3Sintering the ceramic tube at 400-450 ℃ for 2-3 hours;
(4) penetrating a nickel-chromium heating coil with a resistance value of 30-40 omega through Al2O3The interior of the ceramic tube is used as a heating wire;
(5) and (4) welding and packaging the device obtained in the step (4) according to an indirectly heated gas sensitive element, so as to obtain the N-pentanol (N-pentanol) gas sensor based on the ZnO nano sensitive material.
Al2O3The ceramic tube has a length of 4-4.5 mm, an outer diameter of 1.2-1.5 mm and an inner diameter of 0.8-1.0 mm. Al (Al)2O3The surface of the ceramic tube is covered with annular Au electrodes, the width of the Au electrodes is 0.4-0.5 mm, and the distance between every two adjacent Au electrodes is 0.5-0.6 mm.
The N-pentanol gas sensor based on the ZnO nano sensitive material prepared by the invention has the following advantages:
1. the ZnO nano sensitive material can be prepared by a simple hydrothermal method, the synthetic method is simple, and the cost is low;
2. the optimization of oxygen species on the surface of the material can be realized by changing the temperature rise speed of the sensitive material during sintering, so that the sensitivity of the sensor to N-pentanol is improved, and the sensor has quick response recovery speed and good repeatability and has wide application prospect in the aspect of detecting the content of the N-pentanol;
3. the tube sensor is commercially available, and the device has simple process and small volume and is suitable for mass production.
Drawings
FIG. 1: SEM topography of the ZnO nano sensitive material prepared in example 1; wherein (a) the magnification of the graph is 3300 times, and (b) the magnification of the graph is 1000 times;
FIG. 2: XRD pattern of ZnO nano-sensing material prepared in example 1;
FIG. 3: comparison of the selectivity of the sensors in comparative example 1, comparative example 2 and example 1 with the operating temperature of 300 ℃ for 100ppm of the different gases;
FIG. 4: the sensitivity of the sensor in example 1 at the optimum operating temperature is plotted against the N-pentanol concentration.
As shown in FIG. 1, the ZnO nano sensitive material is in a hexagonal flower-shaped structure, the nanoflowers are composed of porous nanosheets, the diameter of the nanoflowers is 13-16 microns, the length of the nanosheets is 5-7 microns, and the nanomaterial has good uniformity;
as shown in fig. 2, the XRD spectrogram of the ZnO nano-sensing material can see the characteristic peak of ZnO, indicating that the sample is a pure phase;
as shown in fig. 3, the sensor in the embodiment has a higher response to N-pentanol. And compared with comparative example 1 and comparative example 2, the selectivity of the sensor in the examples is greatly improved, and the sensitivity of the device to 100ppm of N-pentanol is 5.1, 3.9 and 22.1 respectively;
as shown in fig. 4, when the device operating temperature is 300 ℃, the sensitivity of the sensor in the embodiment increases with the increase of the N-pentanol concentration at the optimal operating temperature;
note: the sensitivity of the device is defined as the resistance value (R) in air between two gold electrodes of the sensora) And resistance value (R) in the measured gasg) The ratio is S ═ Ra/Ra. During the testing process, a dynamic testing system is used for testing. Placing the device in a 1L closed container filled with air, and recording the resistance of the sensor as Ra. Injecting a certain amount of organic gas to be measured, observing and recording the resistance value change, and recording the resistance value R when the resistance is stablegAnd calculating to obtain corresponding sensitivity value.
Detailed Description
Comparative example 1:
1. preparing a sensitive material: firstly, 0.3g of zinc nitrate and 0.3g of urea are added into 35mL of deionized water and stirred for 60min until the zinc nitrate and the urea are completely dissolved; the solution was put into a 50mL hydrothermal kettle and reacted at 140 ℃ for 5 hours. Then, the obtained product is washed by centrifugation alternately by water and ethanol, and the working parameter of the centrifuge is set to 10000r min-1Drying the product after centrifugal washing at 80 deg.C for 12 hr, calcining at 450 deg.C for 2 hr, and setting the temperature rise rate at 1 deg.C for min-1Preparing ZnO nano sensitive material;
2. coating sensitive materials: 2g of ZnO nano sensitive material is mixed with 3mL of deionized water and ground to form pasty slurry, and then a small amount of slurry is dipped and evenly coated on Al of which the outer surface is provided with two parallel, annular and mutually separated gold electrodes2O3Forming a sensitive material film with the thickness of 30 mu m on the surface of the ceramic tube, completely covering the annular gold electrode with the sensitive material, and coating Al2O3Baking the ceramic tube at 70 ℃ for 30 minutes, and drying the sensitive material, and then adding Al2O3Calcining the ceramic tube at 450 ℃ for 2 hours;
3. n-pentanol (N-pentanol) gas sensor device soldering: a nickel-chromium heating coil having a resistance value of 30 Ω was passed through Al2O3And finally, welding and packaging the device according to a general indirectly heated gas sensitive element by using the inside of the ceramic tube as a heating wire, thereby obtaining the N-pentanol (N-pentanol) gas sensor based on the ZnO nano sensitive material.
Comparative example 2:
1. preparing a sensitive material: firstly, 0.3g of zinc nitrate and 0.3g of urea are added into 35mL of deionized water and stirred for 60min until the zinc nitrate and the urea are completely dissolved; the solution was put into a 50mL hydrothermal kettle and reacted at 140 ℃ for 5 hours. Then, the obtained product is washed by centrifugation alternately by water and ethanol, and the working parameter of the centrifuge is set to 10000r min-1Drying the product after centrifugal washing at 80 deg.C for 12 hr for 10min, and drying at 450 deg.CCalcining for 2h, and setting the temperature rise rate to 10 deg.C for min-1Preparing ZnO nano sensitive material;
2. coating sensitive materials: 2g of ZnO nano sensitive material is mixed with 3mL of deionized water and ground to form pasty slurry, and then a small amount of slurry is dipped and evenly coated on Al of which the outer surface is provided with two parallel, annular and mutually separated gold electrodes2O3Forming a sensitive material film with the thickness of 30 mu m on the surface of the ceramic tube, completely covering the annular gold electrode with the sensitive material, and coating Al2O3Baking the ceramic tube at 70 ℃ for 30 minutes, and drying the sensitive material, and then adding Al2O3Calcining the ceramic tube at 450 ℃ for 2 hours;
3. n-pentanol (N-pentanol) gas sensor device soldering: a nickel-chromium heating coil having a resistance value of 30 Ω was passed through Al2O3And finally, welding and packaging the device according to a general indirectly heated gas sensitive element by using the inside of the ceramic tube as a heating wire, thereby obtaining the N-pentanol (N-pentanol) gas sensor based on the ZnO nano sensitive material.
Example 1:
1. preparing a sensitive material: firstly, 0.3g of zinc nitrate and 0.3g of urea are added into 35mL of deionized water and stirred for 60min until the zinc nitrate and the urea are completely dissolved; the solution was put into a 50mL hydrothermal kettle and reacted at 140 ℃ for 5 hours. Then, the obtained product is washed by centrifugation alternately by water and ethanol, and the working parameter of the centrifuge is set to 10000r min-1Drying the product after centrifugal washing at 80 deg.C for 12 hr, calcining at 450 deg.C for 2 hr, and setting the temperature rise rate at 5 deg.C for 5 min-1Preparing ZnO nano sensitive material;
2. coating sensitive materials: 2g of ZnO nano sensitive material is mixed with 3mL of deionized water and ground to form pasty slurry, and then a small amount of slurry is dipped and evenly coated on Al of which the outer surface is provided with two parallel, annular and mutually separated gold electrodes2O3Forming a sensitive material film with the thickness of 30 mu m on the surface of the ceramic tube, completely covering the annular gold electrode with the sensitive material, and coating Al2O3Ceramic tubes at 70 deg.CBaking for 30 minutes, drying the sensitive material, and adding Al2O3Calcining the ceramic tube at 450 ℃ for 2 hours;
3. n-pentanol (N-pentanol) gas sensor device soldering: a nickel-chromium heating coil having a resistance value of 30 Ω was passed through Al2O3And finally, welding and packaging the device according to a general indirectly heated gas sensitive element by using the inside of the ceramic tube as a heating wire, thereby obtaining the N-pentanol (N-pentanol) gas sensor based on the ZnO nano sensitive material.
Claims (3)
1. An n-amyl alcohol gas sensor based on ZnO nano-sensitive material is composed of Al whose external surface has two parallel, annular and mutually separated gold electrodes2O3Ceramic tube substrate coated with Al2O3Sensitive material on the outer surface of the ceramic tube and the gold electrode, Al2O3A nickel-chromium heating coil in the ceramic tube; the method is characterized in that: the sensitive material is a ZnO nano sensitive material, and the ZnO nano sensitive material is prepared by the following steps:
(1) adding 0.3-0.35 g of zinc nitrate and 0.3-0.35 g of urea into 35-40 mL of deionized water, and stirring for 60-70 min until the zinc nitrate and the urea are completely dissolved; putting the solution into a 50mL hydrothermal kettle, and reacting for 5-6 h at 140-150 ℃;
(2) and (2) alternately carrying out centrifugal washing on the product obtained in the step (1) by using water and ethanol, wherein the centrifugal speed is 10000-11000 r min-1Centrifuging for 10-12 min;
(3) drying the product centrifugally washed in the step (2) at 80-85 ℃ for 12-13 h;
(4) calcining the dried product obtained in the step (3) at 450-500 ℃ for 1-2 h, wherein the temperature rise speed of the calcination is 4-6 ℃ for min-1Thereby preparing the ZnO nano sensitive material.
2. The n-amyl alcohol gas sensor based on the ZnO nano sensitive material as claimed in claim 1, wherein: al (Al)2O3The ceramic tube has a length of 4-4.5 mm, an outer diameter of 1.2-1.5 mm and an inner diameter of 0.8-1.0 mm; the width of the gold electrode is0.4-0.5 mm, and the distance between gold electrodes is 0.5-0.6 mm.
3. The preparation method of the n-amyl alcohol gas sensor based on the ZnO nano sensitive material, which is disclosed by claim 1 or 2, comprises the following steps:
(1) mixing 1-2 g of ZnO nano sensitive material with 2-3 mL of deionized water, and grinding to form pasty slurry;
(2) then dipping a small amount of slurry to evenly coat Al with two parallel, annular and separated gold electrodes on the outer surface2O3Forming a sensitive material film with the thickness of 20-30 mu m on the surface of the ceramic tube, and enabling the sensitive material to completely cover the annular gold electrode;
(3) coated Al2O3Baking the ceramic tube at 50-100 ℃ for 30-45 minutes, and drying the sensitive material, and then, adding Al2O3Sintering the ceramic tube at 400-450 ℃ for 2-3 hours;
(4) penetrating a nickel-chromium heating coil with a resistance value of 30-40 omega through Al2O3The interior of the ceramic tube is used as a heating wire;
(5) and (4) welding and packaging the device obtained in the step (4) according to an indirectly heated gas sensitive element, so as to obtain the n-amyl alcohol gas sensor based on the ZnO nano sensitive material.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111830089A (en) * | 2020-08-20 | 2020-10-27 | 吉林大学 | Based on two shell shape Cu2N-propanol gas sensor of O-grade structure micron sphere sensitive material and preparation method thereof |
| CN113189153A (en) * | 2021-05-11 | 2021-07-30 | 吉林大学 | Ethanol sensor based on ZnO porous nanosheet microsphere sensitive material, preparation method and application thereof |
| CN113219010A (en) * | 2021-05-19 | 2021-08-06 | 吉林大学 | Ethanol sensor of ZnO double-shell hollow structure microsphere sensitive material and preparation |
| CN113433174A (en) * | 2021-07-02 | 2021-09-24 | 吉林大学 | Ethanol sensor based on ZnO porous structure microsphere sensitive material, preparation method and application thereof |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111830089A (en) * | 2020-08-20 | 2020-10-27 | 吉林大学 | Based on two shell shape Cu2N-propanol gas sensor of O-grade structure micron sphere sensitive material and preparation method thereof |
| CN113189153A (en) * | 2021-05-11 | 2021-07-30 | 吉林大学 | Ethanol sensor based on ZnO porous nanosheet microsphere sensitive material, preparation method and application thereof |
| CN113219010A (en) * | 2021-05-19 | 2021-08-06 | 吉林大学 | Ethanol sensor of ZnO double-shell hollow structure microsphere sensitive material and preparation |
| CN113433174A (en) * | 2021-07-02 | 2021-09-24 | 吉林大学 | Ethanol sensor based on ZnO porous structure microsphere sensitive material, preparation method and application thereof |
Non-Patent Citations (3)
| Title |
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| BENXIA LI ET AL.: "Hierarchically assembled porous ZnO microstructures and applications in a gas sensor", 《SUPERLATTICES AND MICROSTRUCTURES》 * |
| HONGTAO WANG ET AL.: "N-pentanol sensor based on ZnO nanorods functionalized with Au catalysts", 《SENSORS AND ACTUATORS: B. CHEMICAL》 * |
| XIAOFENG WANG ET AL.: "Surface Structure Engineering of Nanosheet-Assembled NiFe2O4 Fluffy Flowers for Gas Sensing", 《NANOMATERIALS》 * |
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Application publication date: 20220111 |