A photoactivated SnO2 spherical aperture array gas sensor, its fabrication method and application

Abstract

The application discloses a light-activated SnO2 spherical pore array gas sensor and a preparation method and application thereof. The preparation method of the light-activated SnO2 spherical pore array gas sensor uses a solution containing a surfactant and Sn 2+ as an electrolyte, uses an electrochemical deposition method to prepare a tin film on the surface of a gas-sensitive ceramic substrate covered with a composite film of polystyrene microspheres and redox graphene, is heated to obtain a SnO2 spherical pore array sensor, is light-excited by using an LED-ultraviolet lamp to obtain the light-activated SnO2 spherical pore array gas sensor. The method effectively overcomes the condition that a traditional device needs to work at high temperature and the instability of device performance caused thereby, overcomes the shortcoming that a light-activated device cannot systemically regulate gas-sensitive performance by controlling the light-irradiated area of a film surface, and can further improve the sensor response by doping a noble metal through the light-irradiation method, so that the gas-sensitive performance of the sensor at room temperature is optimized.

Description

Technical Field

[0001] This invention relates to the field of gas sensors, specifically to a photoactivated SnO2 spherical aperture array gas sensor, its preparation method, and its application. Background Technology

[0002] SnO2 is a typical n-type semiconductor and has been widely studied by researchers as a gas-sensitive material. Gas sensors made primarily of SnO2 have many advantages, such as good physical and chemical stability and long operating life. However, SnO2-based gas sensors generally can only operate at high temperatures, which has several drawbacks: high energy consumption, impact on long-term device stability, and shortened sensor lifespan. To meet the need for gas detection at room temperature, noble metals, carbon, or polymers are introduced into the SnO2 matrix to enable room temperature response sensors. However, the relatively low sensing response, long response / recovery time, and cumbersome manufacturing process still significantly limit the application of room temperature sensors. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides a photoactivated SnO2 spherical aperture array gas sensor, its preparation method and application.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] The first aspect of this invention provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, comprising the following steps:

[0006] (1) Coat the polystyrene suspension evenly on a glass slide, dry it, and then immerse the glass slide obliquely in the graphene oxide dispersion to separate the monolayer polystyrene microsphere film. After standing for 20-30 minutes, use a gas-sensitive ceramic tube to take out the film and let it air dry naturally.

[0007] (2) Using a solution containing Sn salt and surfactant as electrolyte, the surface of the gas-sensitive ceramic tube carrying the thin film obtained in step (1) is electrodeposited by electrochemical deposition to obtain a polystyrene / graphene oxide / tin hydroxide composite thin film gas-sensitive ceramic tube.

[0008] (3) The polystyrene / graphene oxide / tin hydroxide composite film gas-sensitive ceramic tube obtained in step (2) is heated to convert the film into a pure SnO2 film, and SnO2 spherical hole array sensor is obtained; then, it is photoexcited by an LED-ultraviolet lamp to obtain the photoactivated SnO2 spherical hole array gas sensor.

[0009] Preferably, in step (3), the SnO2 spherical aperture array sensor is placed in a precursor solution containing noble metal salts, irradiated with a 254nm ultraviolet lamp, and then photoexcited with an LED-ultraviolet lamp to obtain the photoactivated SnO2 spherical aperture array gas sensor.

[0010] This invention utilizes ultraviolet light to activate a SnO2 spherical pore array film to achieve ethanol gas detection at room temperature. By applying a polystyrene template and controlling the electrodeposition time, the morphology of SnO2 is effectively regulated, thereby maximizing the light-receiving area of ​​the film. Furthermore, the sensitivity of SnO2 at room temperature is improved to varying degrees by doping with noble metals through photo-irradiation.

[0011] More preferably, the precursor solution contains at least one of chloroauric acid, silver nitrate, and chloroplatinic acid, wherein the concentration of the noble metal salt is ≤0.25mol / L.

[0012] Preferably, in step (1), the polystyrene in the polystyrene suspension has a particle size of 500-700 nm; and the solid content of the graphene oxide dispersion is 0.34-0.5 mg / mL.

[0013] Preferably, in step (1), the oblique immersion is to make the carrier and the liquid surface form an angle of less than 30°.

[0014] In some specific embodiments of the present invention, the gas-sensitive ceramic tube substrate is covered with conductive films at both ends, electrode lines are welded on the conductive films, and the middle is a non-conductive ceramic surface.

[0015] Preferably, in step (1), the resistance value of the thin film retrieved from the gas-sensitive ceramic tube is 50 to 100 Ω, and it is used as a conductive layer for electrochemical deposition.

[0016] Preferably, in step (2), the electrolyte contains 0.01–0.03 mol / L SnSO4, 0.05–0.15 mol / L NaNO3, and 0.05–0.1 mol / L HNO3; the surfactant is hexadecyltrimethylammonium bromide.

[0017] Preferably, the concentration of the surfactant is ≤0.05g / mL.

[0018] Preferably, in step (2), the electrodeposition current is 0.8 to 1 mA and the time is 10 to 60 min.

[0019] Preferably, in step (3), the heating temperature is 300℃~450℃ and the time is 30~120min.

[0020] In some specific embodiments of the present invention, the heating method in step (3) is as follows: a Ni / cr resistance wire is passed through the gas-sensitive ceramic tube and a voltage is applied to control the surface temperature of the gas-sensitive ceramic tube to 300℃~450℃, and it is calcined for 30~120min to remove the template and reduce the graphene oxide to obtain the SnO2 spherical hole array sensor.

[0021] Preferably, in step (3), the LED-UV lamp has a wavelength of 265nm to 365nm and a light intensity of 10 to 300mW / cm². 2 .

[0022] The second aspect of the present invention provides a method for preparing a photoactivated SnO2 spherical aperture array gas sensor, which yields a photoactivated SnO2 spherical aperture array gas sensor.

[0023] The third aspect of this invention provides the application of the aforementioned photoactivated SnO2 spherical aperture array gas sensor in ethanol detection.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention contains surfactant and Sn 2+ Using a solution as the electrolyte, an electrochemical deposition method was employed, with polystyrene microspheres as a template, to prepare a tin thin film on the surface of a gas-sensitive ceramic substrate covered with a composite film of polystyrene microspheres and reduced-oxidation graphene. Upon heating, a spherical aperture array gas sensor with controllable SnO2 surface morphology was obtained. Under LED-UV irradiation, the SnO2 sensor exhibited high sensitivity, good repeatability, and stability for ethanol gas at room temperature. The sensing performance mainly depends on the light-receiving area of ​​the thin film, which can be controlled by adjusting the height of the aperture wall structure through electrodeposition time. This method effectively overcomes the requirement of traditional devices to operate at high temperatures and the resulting instability, and overcomes the limitation of photoactivated devices where gas-sensing performance cannot be systematically controlled by adjusting the light-receiving area of ​​the thin film surface. Furthermore, the sensor's reactivity can be further improved by doping with noble metals through photo-irradiation, achieving optimization of its gas-sensing performance at room temperature. The preparation method described is simple and easy to mass-produce, which improves the problems of high operating temperature, low sensitivity and long response / recovery time of current ethanol gas sensors, and provides an efficient and promising way to prepare SnO2 thin film sensors for room temperature ethanol detection. Attached Figure Description

[0026] Figure 1 This is a scanning electron microscope image of the polystyrene and redox graphene composite film in Example 1;

[0027] Figure 2Scanning electron microscope (SEM) images of polystyrene / redox graphene / tin hydroxide composite films obtained after electrochemical deposition in various embodiments;

[0028] Figure 3 Scanning electron microscope (SEM) images of the SnO2 spherical pore array film after heating to remove the template and graphene oxide in various embodiments;

[0029] Figure 4 The graph shows the response performance of SnO2 spherical hole array gas sensors prepared at different electrodeposition times to ethanol under photoactivation.

[0030] Figure 5 The sensor's response to the ethanol gradient is shown in graphs and its linearity.

[0031] Figure 6 This is a comparison of the response of SnO2 spherical aperture array gas sensors doped with different noble metals to ethanol. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0034] Example 1

[0035] This embodiment provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, specifically including the following steps:

[0036] A monodisperse polystyrene (PS) suspension with a size of approximately 600 nm was taken with a glass rod and evenly coated onto a clean glass slide (2.54 × 7.62 cm). 2 The coating area is 2.54 × 4 cm. 2After drying, the glass slide was tilted at 30° and slowly immersed in a reduced graphene oxide solution (0.34 mg / mL). The PS microsphere film naturally separated from the glass slide and floated on the surface of the reduced graphene oxide solution. After standing for 30 minutes, the lower part of the PS template was absorbed and wrapped by the reduced graphene oxide nanosheets, forming a composite film (the reduced graphene oxide sheets act as an auxiliary conductive layer, providing conductivity for the ceramic tube). A clean gas-sensitive ceramic tube (Weisheng ceramic tube, containing a ceramic tube and a heating wire; the ceramic tube lead is made of platinum wire, and the heating wire is made of nickel-chromium material; dimensions: length * outer diameter * wall thickness 4 * 1.35 * 0.35 mm; the ceramic tube platinum wire has a high temperature resistance of ≤800 degrees Celsius, and the heating wire has a high temperature resistance of approximately 600-700 degrees Celsius; heating resistance is approximately 28-29 Ω) was used as a substrate. The film was then retrieved and air-dried naturally. The composite film resistance was approximately 70 Ω. Subsequently, the electrode wire of the ceramic tube was connected to the working electrode of the potentiostat as the cathode. The entire tube was then immersed in 30 mL of electrolyte containing 0.02 M SnSO4, 0.1 M NaNO3, 0.075 M HNO3, and 2 mM CTAB, with the graphite electrode and cathode connected. A constant current of 0.8 mA was applied for 10 min, after which the ceramic tube was removed, rinsed with deionized water, and dried. Finally, a Ni / cr resistance wire was passed through the ceramic tube, and a voltage of 6.0 V was applied, measuring the surface temperature of the tube at 400 °C. After calcination for 1 h, the template and reduced graphene oxide were removed to obtain a SnO2 spherical aperture array sensor. At a wavelength of 265 nm, the light intensity was 15.57 mW / cm². 2 Detection of ethanol gas under LED-UV light activation.

[0037] Example 2

[0038] This embodiment provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, specifically including the following steps:

[0039] A monodisperse polystyrene (PS) suspension with a size of approximately 600 nm was taken with a glass rod and evenly coated onto a clean glass slide (2.54 × 7.62 cm). 2 The coating area is 2.54 × 4 cm. 2After drying, the glass slide was tilted at 30° and slowly immersed in a reduced graphene oxide solution (0.34 mg / mL). The PS microsphere film naturally separated from the glass slide and floated on the surface of the reduced graphene oxide solution. After standing for 30 minutes, the lower part of the PS template was absorbed and wrapped by the reduced graphene oxide nanosheets, forming a composite film (the reduced graphene oxide sheets act as an auxiliary conductive layer, providing conductivity for the ceramic tube). A clean gas-sensitive ceramic tube was selected as the substrate, and the film was retrieved and air-dried naturally. The resistance of the composite film was approximately 70 Ω. Subsequently, the electrode wire of the ceramic tube was connected to the working electrode of the potentiostat as the cathode; then the entire tube was immersed in 30 mL of electrolyte containing 0.02 M SnSO4, 0.1 M NaNO3, 0.075 M HNO3, and 2 mM MCTAB, and the graphite electrode and cathode were connected; a constant current of 0.8 mA was applied for 30 minutes, the ceramic tube was removed, rinsed with deionized water, and dried. Finally, a Ni / cr resistance wire was passed through the ceramic tube, and a voltage of 6.0V was applied. The surface temperature of the tube was measured to be 400℃. After calcination for 1 hour, the template and reduced graphene oxide were removed to obtain a SnO2 spherical aperture array sensor. At a wavelength of 265nm, the light intensity was 15.57mW / cm². 2 Detection of ethanol gas under LED-UV light activation.

[0040] Example 3

[0041] This embodiment provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, specifically including the following steps:

[0042] A monodisperse polystyrene (PS) suspension with a size of approximately 600 nm was taken with a glass rod and evenly coated onto a clean glass slide (2.54 × 7.62 cm). 2 The coating area is 2.54 × 4 cm. 2After drying, the glass slide was tilted at 30° and slowly immersed in a reduced graphene oxide solution (0.34 mg / mL). The PS microsphere film naturally separated from the glass slide and floated on the surface of the reduced graphene oxide solution. After standing for 30 min, the lower part of the PS template was absorbed and wrapped by the reduced graphene oxide nanosheets, forming a composite film (the reduced graphene oxide sheets act as an auxiliary conductive layer, providing conductivity for the ceramic tube). A clean gas-sensitive ceramic tube was selected as the substrate, and the film was retrieved and air-dried naturally. The resistance of the composite film was approximately 70 Ω. Subsequently, the electrode wire of the ceramic tube was connected to the working electrode of the potentiostat as the cathode; then the entire tube was immersed in 30 mL of electrolyte containing 0.02 M SnSO4, 0.1 M NaNO3, 0.075 M HNO3, and 2 mM MCTAB, and the graphite electrode and cathode were connected; a constant current of 0.8 mA was applied for 50 min, the ceramic tube was removed, rinsed with deionized water, and dried. Finally, a Ni / cr resistance wire was passed through the ceramic tube, and a voltage of 6.0V was applied. The surface temperature of the tube was measured to be 400℃. After calcination for 1 hour, the template and reduced graphene oxide were removed to obtain a SnO2 spherical aperture array sensor. At a wavelength of 265nm, the light intensity was 15.57mW / cm². 2 Detection of ethanol gas under LED-UV light activation.

[0043] Example 4

[0044] This embodiment provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, specifically including the following steps:

[0045] A monodisperse polystyrene (PS) suspension with a size of approximately 600 nm was taken with a glass rod and evenly coated onto a clean glass slide (2.54 × 7.62 cm). 2 The coating area is 2.54 × 4 cm. 2After drying, the glass slide was tilted at 30° and slowly immersed in a reduced graphene oxide solution (0.34 mg / mL). The PS microsphere film naturally separated from the glass slide and floated on the surface of the reduced graphene oxide solution. After standing for 30 min, the lower part of the PS template was absorbed and wrapped by the reduced graphene oxide nanosheets, forming a composite film (the reduced graphene oxide sheets act as an auxiliary conductive layer, providing conductivity for the ceramic tube). A clean gas-sensitive ceramic tube was selected as the substrate, and the film was retrieved and air-dried naturally. The resistance of the composite film was approximately 70 Ω. Subsequently, the electrode wire of the ceramic tube was connected to the working electrode of the potentiostat as the cathode; then the entire tube was immersed in 30 mL of electrolyte containing 0.02 M SnSO4, 0.1 M NaNO3, 0.075 M HNO3 and 2 mM MCTAB, and the graphite electrode and cathode were connected; a constant current of 0.8 mA was applied for 60 min, the ceramic tube was removed, rinsed with deionized water and dried. Finally, a Ni / cr resistance wire was passed through the ceramic tube, and a voltage of 6.0V was applied. The surface temperature of the tube was measured to be 400℃. After calcination for 1 hour, the template and reduced graphene oxide were removed to obtain a SnO2 spherical aperture array sensor. At a wavelength of 265nm, the light intensity was 15.57mW / cm². 2 Detection of ethanol gas under LED-UV light activation.

[0046] Example 5

[0047] This embodiment provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, specifically including the following steps:

[0048] A monodisperse polystyrene (PS) suspension with a size of approximately 600 nm was taken with a glass rod and evenly coated onto a clean glass slide (2.54 × 7.62 cm). 2 The coating area is 2.54 × 4 cm. 2After drying, the glass slide was tilted at 30° and slowly immersed in a reduced graphene oxide solution (0.34 mg / mL). The PS microsphere film naturally separated from the glass slide and floated on the surface of the reduced graphene oxide solution. After standing for 30 minutes, the lower part of the PS template was absorbed and wrapped by the reduced graphene oxide nanosheets, forming a composite film (the reduced graphene oxide sheets act as an auxiliary conductive layer, providing conductivity for the ceramic tube). A clean gas-sensitive ceramic tube was selected as the substrate, and the film was retrieved and air-dried naturally. The resistance of the composite film was approximately 70 Ω. Subsequently, the electrode wire of the ceramic tube was connected to the working electrode of the potentiostat as the cathode; then the entire tube was immersed in 30 mL of electrolyte containing 0.02 M SnSO4, 0.1 M NaNO3, 0.075 M HNO3, and 2 mM MCTAB, and the graphite electrode and cathode were connected; a constant current of 0.8 mA was applied for 30 minutes, the ceramic tube was removed, rinsed with deionized water, and dried. Finally, a Ni / cr resistance wire was passed through the ceramic tube, and a voltage of 6.0V was applied. The surface temperature of the tube was measured to be 400℃. After calcination for 1 hour, the template and reduced graphene oxide were removed to obtain a SnO2 spherical array sensor. The ceramic tube containing the SnO2 gas-sensitive element was placed in a weighing bottle containing a 0.24mol / L chloroauric acid solution. The weighing bottle was then irradiated for 20 minutes under two 254nm UV lamps to obtain an Au-doped SnO2 spherical aperture array sensor. At a wavelength of 265nm, the light intensity was 15.57mW / cm². 2 Detection of ethanol gas under LED-UV light activation.

[0049] Example 6

[0050] This embodiment provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, specifically including the following steps:

[0051] A monodisperse polystyrene (PS) suspension with a size of approximately 600 nm was taken with a glass rod and evenly coated onto a clean glass slide (2.54 × 7.62 cm). 2 The coating area is 2.54 × 4 cm. 2After drying, the glass slide was tilted at 30° and slowly immersed in a reduced graphene oxide solution (0.34 mg / mL). The PS microsphere film naturally separated from the glass slide and floated on the surface of the reduced graphene oxide solution. After standing for 30 minutes, the lower part of the PS template was absorbed and wrapped by the reduced graphene oxide nanosheets, forming a composite film (the reduced graphene oxide sheets act as an auxiliary conductive layer, providing conductivity for the ceramic tube). A clean gas-sensitive ceramic tube was selected as the substrate, and the film was retrieved and air-dried naturally. The resistance of the composite film was approximately 70 Ω. Subsequently, the electrode wire of the ceramic tube was connected to the working electrode of the potentiostat as the cathode; then the entire tube was immersed in 30 mL of electrolyte containing 0.02 M SnSO4, 0.1 M NaNO3, 0.075 M HNO3, and 2 mM MCTAB, and the graphite electrode and cathode were connected; a constant current of 0.8 mA was applied for 30 minutes, the ceramic tube was removed, rinsed with deionized water, and dried. Finally, a Ni / cr resistance wire was passed through the ceramic tube, and a voltage of 6.0V was applied. The surface temperature of the tube was measured to be 400℃. After calcination for 1 hour, the template and reduced graphene oxide were removed to obtain a SnO2 spherical array sensor. The ceramic tube containing the SnO2 gas-sensitive element was placed in a weighing bottle containing a 0.05mol / L silver nitrate solution. The weighing bottle was then irradiated for 20 minutes under two 254nm UV lamps to obtain an Ag-doped SnO2 spherical aperture array sensor. At a wavelength of 265nm, the light intensity was 15.57mW / cm². 2 Detection of ethanol gas under LED-UV light activation.

[0052] Example 7

[0053] This embodiment provides a method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, specifically including the following steps:

[0054] A monodisperse polystyrene (PS) suspension with a size of approximately 600 nm was taken with a glass rod and evenly coated onto a clean glass slide (2.54 × 7.62 cm). 2 The coating area is 2.54 × 4 cm. 2After drying, the glass slide was tilted at 30° and slowly immersed in a reduced graphene oxide solution (0.34 mg / mL). The PS microsphere film naturally separated from the glass slide and floated on the surface of the reduced graphene oxide solution. After standing for 30 minutes, the lower part of the PS template was absorbed and wrapped by the reduced graphene oxide nanosheets, forming a composite film (the reduced graphene oxide sheets act as an auxiliary conductive layer, providing conductivity for the ceramic tube). A clean gas-sensitive ceramic tube was selected as the substrate, and the film was retrieved and air-dried naturally. The resistance of the composite film was approximately 70 Ω. Subsequently, the electrode wire of the ceramic tube was connected to the working electrode of the potentiostat as the cathode; then the entire tube was immersed in 30 mL of electrolyte containing 0.02 M SnSO4, 0.1 M NaNO3, 0.075 M HNO3, and 2 mM MCTAB, and the graphite electrode and cathode were connected; a constant current of 0.8 mA was applied for 30 minutes, the ceramic tube was removed, rinsed with deionized water, and dried. Finally, a Ni / cr resistance wire was passed through the ceramic tube, and a voltage of 6.0V was applied. The surface temperature of the tube was measured to be 400℃. After calcination for 1 hour, the template and reduced graphene oxide were removed to obtain a SnO2 spherical array sensor. The ceramic tube containing the SnO2 gas-sensitive element was placed in a weighing bottle containing a 0.035mol / L chloroplatinic acid solution. The weighing bottle was then irradiated for 20 minutes under two 254nm UV lamps to obtain a Pt-doped SnO2 spherical aperture array sensor. At a wavelength of 265nm, the light intensity was 15.57mW / cm². 2 Detection of ethanol gas under LED-UV light activation.

[0055] Figure 1 To observe the morphology of the PS / GO composite film. Figure 2 The images in Figures A, B, and C are, in order, morphology images of the polystyrene / reduced graphene / tin hydroxide composite films obtained in Examples 1 to 4, after which the template and graphene oxide were removed by heating. Figure 3 The images in the middle (ad) are morphology diagrams of the SnO2 spherical pore array film.

[0056] Performance testing of SnO2 spherical aperture array sensor under photoexcitation: The ceramic tube-loaded SnO2 spherical aperture array gas sensors obtained in Examples 1-4 were welded onto an ABS substrate and connected to a gas-sensitive testing system. Under LED-UV lamp excitation, 100 ppm ethanol in a room temperature environment was detected, and the performance was obtained as follows: Figure 4 As shown, when the electrodeposition time is 30 min, the SnO2 spherical hole array sensor has excellent response recovery performance and a sensitivity of 22.8.

[0057] Concentration gradient test of SnO2 spherical aperture array sensor under photoexcitation: The SnO2 spherical aperture array sensor obtained in Example 2 was connected to a gas-sensitive instrument to test its response performance under different ethanol concentration gradients. The obtained performance is as follows: Figure 5 As shown in the figure, the sensitivity gradually increases with the increase of the ethanol concentration gradient. A linear fit of the sensitivity to this concentration gradient is shown in the figure, revealing a good linear relationship.

[0058] Performance Comparison of Noble Metal Doped SnO2 Spherical Hole Array Sensors: The ceramic tube-loaded noble metal doped SnO2 spherical hole array gas sensors obtained in Examples 5-7 were connected to a gas-sensitive testing system. Under LED-UV lamp excitation, 100 ppm ethanol was detected in a room temperature environment. The obtained response was compared with that of Example 2. Figure 6 As shown, the SnO2 spherical aperture array sensor exhibits excellent response recovery performance after Au doping, and its sensitivity reaches 133.6.

[0059] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for fabricating a photoactivated SnO2 spherical aperture array gas sensor, characterized in that, Includes the following steps: (1) Coat the polystyrene suspension evenly on a glass slide, dry it, and then immerse the glass slide obliquely into the reduced graphene oxide dispersion to separate the monolayer polystyrene microsphere film. After standing for 20-30 minutes, use a gas-sensitive ceramic tube to take out the film and let it air dry naturally. (2) Using a solution containing Sn salt and surfactant as the electrolyte, the surface of the gas-sensitive ceramic tube carrying the thin film obtained in step (1) is electrodeposited by electrochemical deposition to obtain a polystyrene / reduced graphene oxide / tin hydroxide composite thin film gas-sensitive ceramic tube; the electrolyte contains 0.01~0.03 mol / L SnSO4, 0.05~0.15 mol / L NaNO3, and 0.05~0.1 mol / L HNO3; the surfactant is hexadecyltrimethylammonium bromide; the electrodeposition current is 0.8~1 mA and the time is 30 min; (3) The polystyrene / reduced graphene oxide / tin hydroxide composite film gas-sensitive ceramic tube obtained in step (2) is heated to convert the film into a pure SnO2 film to obtain a SnO2 spherical hole array sensor; then it is photoexcited by an LED-ultraviolet lamp to obtain the photoactivated SnO2 spherical hole array gas sensor.

2. The method for fabricating a photoactivated SnO2 spherical aperture array gas sensor according to claim 1, characterized in that, In step (3), the SnO2 spherical aperture array sensor is placed in a precursor solution containing noble metal salts, irradiated with a 254 nm ultraviolet lamp, and then photoexcited with an LED-ultraviolet lamp to obtain the photoactivated SnO2 spherical aperture array gas sensor.

3. The method for fabricating a photoactivated SnO2 spherical aperture array gas sensor according to claim 2, characterized in that, The precursor solution contains at least one of chloroauric acid, silver nitrate, and chloroplatinic acid, wherein the concentration of the noble metal salt is ≤0.25 mol / L.

4. The method for fabricating a photoactivated SnO2 spherical aperture array gas sensor according to claim 1 or 2, characterized in that, In step (1), the polystyrene in the polystyrene suspension has a particle size of 500~700 nm; the solid content of the graphene oxide dispersion is 0.34~0.5 mg / mL.

5. The method for fabricating a photoactivated SnO2 spherical aperture array gas sensor according to claim 1 or 2, characterized in that, In step (3), the LED-UV lamp has a wavelength of 265 nm to 365 nm and a light intensity of 10 to 300 mW / cm². 2 .

6. The photoactivated SnO2 spherical aperture array gas sensor prepared by the method according to any one of claims 1-3.

7. The application of the photoactivated SnO2 spherical aperture array gas sensor according to claim 6 in ethanol detection.

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