CN114993972B - ZnO nanowire and NO 2 Gas sensor, its preparation and application - Google Patents
ZnO nanowire and NO 2 Gas sensor, its preparation and application Download PDFInfo
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- 238000003786 synthesis reaction Methods 0.000 description 4
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- DAJSVUQLFFJUSX-UHFFFAOYSA-M sodium;dodecane-1-sulfonate Chemical compound [Na+].CCCCCCCCCCCCS([O-])(=O)=O DAJSVUQLFFJUSX-UHFFFAOYSA-M 0.000 description 3
- AYFACLKQYVTXNS-UHFFFAOYSA-M sodium;tetradecane-1-sulfonate Chemical compound [Na+].CCCCCCCCCCCCCCS([O-])(=O)=O AYFACLKQYVTXNS-UHFFFAOYSA-M 0.000 description 3
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- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical group [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- KIYJAMMLWVBYCT-UHFFFAOYSA-N 1-oxohexane-1-sulfonic acid Chemical compound CCCCCC(=O)S(O)(=O)=O KIYJAMMLWVBYCT-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
The invention belongs to the technical field of gas sensors, and particularly relates to a ZnO nanowire and NO 2 Gas sensor and its preparation and application. According to the invention, the ZnO nanowire prepared by a hydrothermal method is used as a sensitive material, and the microstructure and the internal characteristics of ZnO are changed due to the addition of the anionic surfactant, so that the prepared ZnO nanowire has high length-diameter ratio, oxygen vacancy and adsorption oxygen ratio; in addition, the surface of the ZnO nanowire is attached with anionic surfactant molecules, which can be used as a photosensitizing agent irradiated by ultraviolet light. NO based on ZnO nanowires 2 The gas sensor has high sensitivity at room temperature and in darkness, shows higher response and faster response/recovery speed under ultraviolet irradiation, and detects NO in the environment 2 Has wide application prospect in the content aspect.
Description
Technical Field
The invention belongs to the technical field of gas sensors, and particularly relates to a ZnO nanowire and NO 2 Gas sensor and its preparation and application.
Background
Nitrogen dioxide (NO) 2 ) Is a typical toxic and harmful gas, is one of common atmospheric pollutants, and is excessive in NO 2 Can damage the respiratory system of the human body directly and seriously endanger the health of the human body. In addition, NO 2 And can also be dissolved in water vapor to form acid rain which causes secondary damage to the environment. Thus, timely and accurate NO detection is developed 2 Is a work with great practical significance.
The metal oxide semiconductor-based gas sensor is widely used because of the advantages of excellent performance, simple manufacture, low cost and the like. ZnO is a typical n-type metal oxide semiconductor, has excellent thermal/chemical stability, and is one of the most commonly used gas-sensitive materials. However, the existing ZnO nanomaterial-based sensor has the problems of low sensitivity, long response/recovery time, high working temperature and the like, and the practical application range of the ZnO-based gas sensor is greatly limited. Therefore, there is a need for further improvements in ZnO nanomaterials in terms of material synthesis methods, morphology, etc. to improve their sensing properties.
Disclosure of Invention
The invention aims to provide a ZnO nanowire and NO 2 The microstructure of ZnO is changed by adding the anionic surfactant, so that the prepared ZnO nanowire has a high length-diameter ratio. The change of the morphology of the ZnO gas-sensitive material increases the ratio of the reactive sites and oxygen vacancies on the surface of the ZnO gas-sensitive material to the adsorbed oxygen, and improves the NO of the sensor in darkness 2 Is a high sensitivity. The ZnO surface adsorbed anionic surfactant molecule can be used as a photosensitizing agent, so that the utilization rate of the material to ultraviolet light is improved, and better room-temperature NO is finally obtained under ultraviolet light excitation 2 The sensing performance has wide application prospect in practical application.
According to the technical proposal of the invention, the method for synthesizing ZnO nanowires with the assistance of the anionic surfactant comprises the following steps,
a1: adding alkali into the zinc salt solution, and stirring for reaction to obtain a mixed solution I;
a2: adding an anionic surfactant into the mixed solution I, stirring and standing to obtain a mixed solution II, wherein the anionic surfactant is sodium alkyl sulfonate;
a3: and carrying out hydrothermal treatment on the mixed solution II to obtain the ZnO nanowire.
Further, the zinc salt is zinc chloride or zinc acetate and is used for providing a Zn source. The concentration of the zinc salt solution is 0.5-1.0mol/L; taking zinc acetate as an example, the preparation of the zinc salt solution is as follows: adding zinc acetate into water (such as deionized water), and stirring in ice bath for 30-40min.
Further, the alkali is sodium hydroxide or potassium hydroxide, and the alkali can be added in the form of an alkali solution, such as sodium hydroxide solution with a concentration of 10 mol/L.
Further, the molar ratio of the zinc salt to the alkali is 1:20-30.
Further, in the step a1, the stirring reaction (stirring aging) is performed under ice bath condition, and the reaction time is 3-4h.
Further, the molar ratio of the anionic surfactant to the zinc salt is 1-2:10.
specifically, the molecular formula of the sodium alkyl sulfonate is RSO 3 Na, r=c10-C22 alkyl, preferably sodium caproyl sulfonate (C 10 H 21 SO 3 Na), sodium dodecyl sulfonate (C) 12 H 25 SO 3 Na), sodium tetradecyl sulfonate (C) 14 H 29 SO 3 Na) or sodium hexadecylsulfonate (C) 16 H 33 SO 3 Na). The lengths of the C chains are different, the contents of the surfactants adsorbed on the ZnO surface are different, the lengths of the C chains are large, the adsorption capacity is large, the space effect is strong, the diameter of the nanowire is small, and the doping is deeper.
The anionic surfactant may be added as a solution, such as a sodium hexadecyl sulfonate solution at a concentration of 0.0375 mol/L.
Further, in the step a2, stirring is performed for 20-30min, and then standing is performed for 1-2h.
In step a3, hydrothermal treatment is performed at 140-160 ℃ for 1-1.5h.
Further, in the step a3, the separation operation is further included after the heating treatment,
specifically, the separation operation is as follows: cooling the mixture II after the heating treatment to room temperature, transferring the milky precipitate into a beaker filled with absolute ethyl alcohol, fully stirring for 10-15min, filtering, alternately flushing the obtained product with deionized water and absolute ethyl alcohol for 3-5 times, putting into a constant temperature drying oven, continuously drying at 60-80 ℃ for 8-12h, and naturally cooling the temperature to obtain a ZnO powder sample, namely the ZnO nanowire.
The second aspect of the invention provides a ZnO nanowire prepared by the method. The aspect ratio of the ZnO nanowire is 25-250. Specific:
the anionic surfactant is sodium sunflower-base sulfonate, the length-diameter ratio is 25-35, and the diameter is 800-1600nm;
the anionic surfactant is sodium dodecyl sulfonate, the length-diameter ratio is 60-70, and the diameter is 400-600nm;
the anionic surfactant is sodium tetradecyl sulfonate, the length-diameter ratio is 130-145, and the diameter is 150-250nm;
the anionic surfactant is sodium hexadecyl sulfonate, has an slenderness ratio of 235-250 and a diameter of 70-90nm. A third aspect of the invention provides a NO 2 The preparation method of the gas sensor comprises the following steps of b1: dispersing the ZnO nanowire in absolute ethyl alcohol or water to obtain pasty mixed solution;
b2: coating the pasty mixed solution on the electrode surface of a gas sensor carrier to form a sensitive material film, and drying to obtain the NO 2 A gas sensor.
Further, the volume ratio of the ZnO nanowire to the absolute ethyl alcohol is 2-5:1.
further, the thickness of the sensitive material film is 10-30 mu m.
Further, the gas sensor carrier comprises a monocrystalline silicon wafer substrate, a silicon dioxide insulating layer covering the surface of the monocrystalline silicon wafer substrate, and interdigital electrodes integrated on the surface of the silicon dioxide insulating layer.
Specifically, the preparation method of the gas sensor carrier comprises the following steps: and growing a silicon dioxide insulating layer on the monocrystalline silicon substrate, and integrating Cr/Au interdigital electrodes on the monocrystalline silicon substrate covered with the silicon dioxide insulating layer through a photoetching process, a radio frequency sputtering process and a stripping process.
The size of the monocrystalline silicon wafer substrate is 6 x 4 x 0.5mm, the thickness of the silicon dioxide insulating layer is 300nm, 25 pairs of interdigital electrodes are arranged, the width of each interdigital electrode is 20 mu m, the length of each interdigital electrode is 1.5mm, the gap between adjacent interdigital electrodes is 20 mu m, the electrodes are composed of Cr/Au, and the thickness of each electrode is 10nm/100nm.
Furthermore, the surface of the gas sensor carrier is uniformly covered with a sensitive material film formed by the ZnO nano-wires except the interdigital electrodes.
Further, in the step b2, the drying temperature is 80-100 ℃ and the drying time is 8-12h.
In a fourth aspect, the present invention provides NO produced by the above-described production method 2 A gas sensor.
Further, the device also comprises an illumination module, wherein the illumination module is used for carrying out UV (ultraviolet) light irradiation on the sensitive material film.
A fifth aspect of the present invention provides the ZnO nanowire, or NO 2 The gas sensor detects NO at room temperature (25+ -5deg.C) 2 Is used in the application of (a).
Compared with the prior art, the technical scheme of the invention has the following advantages:
the preparation method of the ZnO nanowire based on the anionic surfactant assisted synthesis provided by the invention can prepare the ZnO nanowire with the diameter of 50-120nm and the high length-diameter ratio, and the ZnO nanowire is covered on the outer surface of the sensor carrier to prepare NO 2 Because the prepared ZnO nanowire has high length-diameter ratio and the ZnO nanowire is doped by surfactant ions, the sensor increases the reactive sites on the surface of the gas-sensitive material and the ratio of oxygen vacancies to adsorbed oxygen, and is beneficial to more NO 2 The sensor is adsorbed on the surface of the gas-sensitive material to participate in the reaction, so that the sensing performance of the sensor is further improved;
NO of the invention 2 The gas sensor also comprises an illumination module, and the anionic surfactant can be used as a soft template to form bonding with the precursor in the hydrothermal solution to perform in-situ functionalization on the prepared ZnO nanowire, so that the prepared ZnO nanowire-based NO 2 The performance of the gas sensor can be further improved under the irradiation of room temperature UV, and the NO with high room temperature sensitivity and fast response/recovery speed is realized 2 A gas sensor;
the sensor in the technical scheme of the invention can be manufactured based on the planar gas sensor as a carrier, has simple device process and small volume, is suitable for mass production, and is applied to practical application.
Drawings
Fig. 1 is an SEM topography of ZnO nanowires prepared according to the present invention, wherein (a) is an SEM topography of pure ZnO nanorods and (b) - (e) are SEM topography of ZnO nanowires prepared according to examples 1-4.
Fig. 2 is an XRD pattern based on ZnO nanowires prepared in the present invention, wherein (a) pattern is an all-angle diffraction pattern of the prepared sample, and (b) pattern is an enlarged view of the prepared sample at 30 ° -39 °.
FIG. 3 is an FT-IR chart based on ZnO nanowires prepared in the present invention.
FIG. 4 is an XPS graph of a ZnO nanowire prepared according to the present invention, in which (a) is a comparison of S2 p nuclear spectra of ZnO nanowires prepared according to examples 1-4, (b) is an XPS peak area ratio of Zn2p to S2 p prepared according to examples 1-4, and (c) is an oxygen vacancy (O) in a prepared pure ZnO nanorod and a ZnO nanowire prepared according to examples 1-4 V ) Adsorption of oxygen (O) C ) Total content (O) V +O C ) Is a trend of change in (c).
FIG. 5 is a graph of NO produced according to examples 1-4 in the present invention 2 Sensor is used for detecting NO under room temperature dark condition 2 Wherein (a) is a dynamic response-recovery curve and (b) is a response-concentration fitting curve.
FIG. 6 is a graph of NO produced according to examples 1-4 in the present invention 2 The sensor was exposed to 10ppmNO under conditions of varying intensity of UV light at room temperature 2 Response curves of (2).
FIG. 7 is a graph of NO produced according to example 4 in the present invention 2 The sensor was exposed to room temperature UV light and room temperature darkness to 10ppmNO 2 Response-recovery curve of (c).
FIG. 8 is a graph of NO produced according to example 4 in the present invention 2 The sensor was exposed to room temperature UV light at 10ppmNO 2 Is a continuous loop response-recovery curve of (c).
Detailed Description
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Example 1
1. Anionic surfactant assisted synthesis of ZnO nanowires
a1: zinc acetate is weighed and added into deionized water to prepare a mixed solution with the concentration of 0.5mol/L, and the mixed solution is stirred for 30min in an ice bath;
a2: weighing sodium hydroxide solution (10 mol/L) according to a molar ratio of 20/1 based on zinc acetate in the step a1, adding the sodium hydroxide solution into the uniformly stirred mixed solution in the step a1, and stirring and aging the obtained mixed solution for 3 hours in an ice bath;
a3: weighing a surfactant solution (0.0375 mol/L) containing sodium sunflower-base sulfonate according to a molar ratio of 1/10 based on zinc acetate in the step a1 at room temperature, adding the surfactant solution into the mixed solution obtained in the step a2, slightly stirring the mixed solution for 20min, and then standing the mixed solution for 2h;
a4: transferring the solution obtained in the step a3 into a polytetrafluoroethylene-lined high-pressure reaction kettle, and heating to 140 ℃ under a hydrothermal condition for reaction for 1h;
a5: and d, after the reaction kettle in the step a4 is cooled to room temperature, transferring the milky precipitate into a beaker filled with absolute ethyl alcohol, fully stirring for 10min, filtering, alternately flushing the obtained product with deionized water and absolute ethyl alcohol for 3 times, putting the product into a constant-temperature drying oven, continuously drying at 60 ℃ for 12h, and naturally cooling the temperature to obtain the ZnO powder sample.
2. NO based on ZnO nanowires 2 Preparation of the sensor
b1: growing a silicon dioxide insulating layer on a monocrystalline silicon wafer substrate, and integrating Cr/Au interdigital electrodes on the monocrystalline silicon substrate covered with the silicon dioxide insulating layer through a photoetching technology, a radio frequency sputtering technology and a stripping technology to obtain a sensor carrier with a gas sensor function; the size of the monocrystalline silicon wafer substrate is 6 x 4 x 0.5mm, the thickness of the silicon dioxide insulating layer is 300nm, 25 pairs of interdigital electrodes are arranged, the width of a single interdigital is 20 mu m, the length of the single interdigital is 1.5mm, the gap between adjacent interdigital electrodes is 20 mu m, the electrodes consist of Cr/Au, and the thickness is 10nm/100nm;
b2: mixing the ZnO powder sample obtained in the step a5 with absolute ethyl alcohol according to the following 3:1, carrying out ultrasonic treatment for 5min to uniformly disperse the ZnO nanowire, so as to prepare pasty mixed solution containing ZnO nanowires;
b3: uniformly and completely covering the mixed solution obtained in the step b2 on the outer surface of the sensor carrier through spin coating to ensure that the mixed solution completely covers the electrode and form a sensitive material film with the thickness of about 20 mu m;
b4: drying the sensor carrier coated with the sensitive material film in a drying oven at 80 ℃ for 12 hours to obtain NO based on ZnO nanowires 2 A sensor.
Examples 2 to 4
Sodium sunflower-based sulfonate was replaced with sodium dodecyl sulfonate, sodium tetradecyl sulfonate and sodium hexadecyl sulfonate, respectively, on the basis of example 1.
Comparative example NO based on pure ZnO nanorods 2 Sensor and preparation thereof
1. The preparation method of the pure ZnO nano rod comprises the following steps:
a1: zinc acetate is weighed and added into deionized water to prepare a mixed solution with the concentration of 0.5mol/L, and the mixed solution is stirred for 30min in an ice bath;
a2: weighing sodium hydroxide solution (10 mol/L) according to a molar ratio of 20/1 based on zinc acetate in the step a1, adding the sodium hydroxide solution into the uniformly stirred mixed solution in the step a1, and stirring and aging the obtained mixed solution for 3 hours in an ice bath;
a3: transferring the solution obtained in the step a2 into a polytetrafluoroethylene-lined high-pressure reaction kettle, and heating to 140 ℃ under a hydrothermal condition for reaction for 1h;
a4: and d, after the reaction kettle in the step a3 is cooled to room temperature, transferring the precipitate into a beaker filled with absolute ethyl alcohol, fully stirring for 10min, filtering, alternately flushing the obtained product with deionized water and absolute ethyl alcohol for 3 times, putting the product into a constant-temperature drying oven, continuously drying at 60 ℃ for 12h, and naturally cooling the temperature of the reaction kettle to obtain the pure ZnO powder sample.
2. Pure ZnO-based nanorod NO 2 The preparation method of the sensor comprises the following steps:
b1: preparing a sensor carrier having a gas sensor function;
b2: the ZnO powder sample obtained in comparative example a4 and absolute ethanol were mixed according to 3:1, carrying out ultrasonic treatment for 5min to uniformly disperse the mixture, and preparing pasty mixed solution containing pure ZnO nano rods;
b3: uniformly and completely covering the mixed solution obtained in the step b2 on the outer surface of the sensor carrier through spin coating to ensure that the mixed solution completely covers the electrode and form a sensitive material film with the thickness of about 20 mu m;
b4: drying the sensor carrier coated with the sensitive material film in a drying oven at 80 ℃ for 12 hours to obtain the NO based on the pure ZnO nano rod 2 A sensor.
Analysis of results
As shown in fig. 1 (a), pure ZnO is a nanorod structure with a larger diameter, while ZnO prepared based on examples 1 to 4 is shown in fig. 1 (b) to (e), which is a nanowire structure with a smaller diameter, and as the chain length of the added surfactant C increases, the diameter of the ZnO nanowire shown in fig. (b) to (e) decreases and the aspect ratio increases.
As shown in fig. 2 (a), all peak positions of the pure ZnO nanorods (comparative examples) and the ZnO nanowires prepared in examples 1 to 4 were identical to the standard peaks, indicating successful preparation of the pure ZnO nanorods and the ZnO nanowires of examples 1 to 4, but the peak positions of the ZnO nanowires prepared in examples 1 to 4 were shifted to a small angle and the shift angles of examples 1 to 4 were gradually increased, as shown in fig. 2 (b), indicating an increase in the surfactant C chain, an increase in the amount of adsorbed ZnO surfactant, resulting in an increase in lattice constant of the prepared ZnO nanowires, and deeper doping, compared to the pure ZnO.
As shown in FIG. 3, pure ZnO does not have any characteristic peak due to no surfactant added, whereas ZnO nanowires synthesized with the aid of anionic surfactant have characteristic peaks due to-CH, respectively 2 Asymmetric stretching vibration of the radical (2906 cm -1 ) And symmetrical telescopic vibration (2838 cm) -1 )，-SO 3 Asymmetric stretching vibration of the s=o bond in the group (1170 cm -1 ) And symmetrical telescopic vibration (1056 cm) -1 ) -CH 2 In-plane bending vibration of the group (1421 cm -1 ) The resulting characteristic peaks, the ZnO peaks prepared in examples 1-4, were progressively stronger, indicating an anionic tableThe surfactant molecules interact with the surface of the ZnO crystal and are finally adsorbed on the surface of the ZnO crystal, and the adsorption amount of the surfactant gradually increases along with the increase of the length of the C chain. Furthermore, during the growth of ZnO crystals, the anionic surfactant forms micelles and aggregates at the ZnO grain surface, and this steric effect is believed to be a potential cause of the formation of high aspect ratio of ZnO crystals by inhibition of radial growth;
as shown in FIG. 4 (a), the peak area of S2 p was gradually increased, and the sharp decrease in the peak area ratio of Z2 p to S2 p shown in FIG. 4 (b) all showed a sharp increase in the content of the anionic surfactant adsorbed on the ZnO surface, and as shown in FIG. 4 (c), the oxygen vacancies (O) of the ZnO nanowires prepared in examples 1 to 4 V ) With adsorption of oxygen (O) C ) The total content is gradually increased, so that the ZnO synthesized by the anionic surfactant has rich defects, and is beneficial to enhancing the gas sensing response;
as shown in FIG. 5 (a), the sensors prepared based on examples 1-4 had responses with NO in a dark environment at room temperature 2 Increasing concentration and increasing response values of the sensors prepared according to examples 1-4 at the same concentration, in FIG. 5 (b), the sensor responses prepared according to examples 1-4 are linear with concentration and the slope of the fitted curve increases gradually, indicating that the prepared sensor has NO 2 The discrimination capability of the gas concentration gradually increases.
As shown in FIG. 6, the sensors prepared based on comparative examples and examples 1-4 were exposed to 10ppm NO at different light intensities when the sensors were exposed to room temperature UV light 2 The response of the sensor prepared in comparative example and example 1 was increased and decreased at 0.42mW/cm 2 Maximum response was obtained for the sensors prepared in examples 2-4 at 0.68mW/cm 2 The maximum response was obtained and the response of the sensors prepared in examples 1-4 was much higher than that of the comparative example sensor, regardless of dark and UV light, demonstrating that the anionic surfactant-assisted synthesized ZnO nanowires have excellent NO 2 Sensing performance.
As shown in FIG. 7, the sensor prepared based on example 4 was irradiated with UV light (0.68 mW/cm at room temperature 2 ) For 10ppmNO under irradiation environment 2 Is 602% in response to58s between, 91s recovery time, and 10ppmNO in a dark ambient temperature environment 2 The response of the ZnO nanowire synthesized by the auxiliary synthesis of the anionic surfactant is 271 percent, the response time is 393s and the recovery time is 953s, and the response/recovery time of the ZnO nanowire synthesized by the auxiliary synthesis of the anionic surfactant under UV illumination are further enhanced, so that the ZnO nanowire has better NO under the UV illumination 2 Sensing performance. Besides the activation of ultraviolet light on ZnO semiconductor, the surfactant molecules adsorbed on the ZnO surface with high length-diameter ratio can be used as photosensitizers to promote the absorption efficiency of ultraviolet light, and finally lead to better photo-excitation of NO 2 Gas sensitive properties.
As shown in FIG. 8, the sensor prepared based on example 4 was irradiated with UV light at room temperature to 10ppm NO 2 The characteristic curve of the sensor is almost unchanged under continuous cycle test, which shows that the sensor of the embodiment has good stability.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (8)
1. NO (NO) 2 The preparation method of the gas sensor is characterized by comprising the following steps,
a1: adding alkali into the zinc salt solution, and stirring for reaction to obtain a mixed solution I;
a2: adding an anionic surfactant into the mixed solution I, stirring and standing to obtain a mixed solution II, wherein the anionic surfactant is sodium alkyl sulfonate;
a3: carrying out hydrothermal treatment on the mixed solution II to obtain ZnO nanowires;
b1: dispersing the ZnO nanowire in absolute ethyl alcohol or water to obtain pasty mixed solution;
b2: coating the pasty mixed liquid on the surface of the electrode of the gas sensor carrierForming a sensitive material film, and drying to obtain the NO 2 A gas sensor.
2. NO according to claim 1 2 The preparation method of the gas sensor is characterized in that the molar ratio of zinc salt to alkali is 1:20-30.
3. NO according to claim 1 2 The preparation method of the gas sensor is characterized in that the molar ratio of the anionic surfactant to the zinc salt is 1-2:10.
4. NO according to claim 1 2 The preparation method of the gas sensor is characterized in that in the step a3, the temperature of the heating treatment is 140-160 ℃ and the time is 1-1.5-h.
5. NO according to claim 1 2 The preparation method of the gas sensor is characterized in that the thickness of the sensitive material film is 10-30 mu m.
6. An NO produced by the production method of any one of claims 1 to 5 2 A gas sensor.
7. The NO according to claim 6 2 A gas sensor, characterized in that the NO 2 The gas sensor further comprises an illumination module for carrying out UV light illumination on the sensitive material film.
8. NO as claimed in claim 6 or 7 2 Gas sensor detects NO at room temperature 2 Is used in the application of (a).
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