CN108931559B - Boron-doped graphene-modified Au @ ZnO core-shell heterojunction type triethylamine gas sensor and preparation method thereof - Google Patents
Boron-doped graphene-modified Au @ ZnO core-shell heterojunction type triethylamine gas sensor and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas sensor and a preparation method thereof, and belongs to the field of triethylamine gas sensors. The gas sensitive material comprises reduced graphene oxide loaded with boron atoms, Au particles and ZnO nanoparticles, wherein the ZnO nanoparticles are coated on the surfaces of gold particles serving as a core structure, the reduced graphene oxide loaded with the boron atoms is attached to the ZnO nanoparticles, the diameter of the Au particles is 100nm-1.5 mu m, the diameter of the ZnO nanoparticles is 30-50nm, and the doping proportion of the boron atoms is controlled to be 3-5%. According to the invention, the characteristics that the core-shell structure of the gas-sensitive material is high in electron transfer speed and the specific surface area of the graphene material is high, and the heterojunction is constructed by the characteristics of the p-type semiconductor of the boron-doped graphene and the ZnO of the shell layer, so that the gas-sensitive performance can be improved are utilized, and the high-sensitivity detection of the toxic and explosive gas triethylamine can be realized at the room temperature.
Description
Technical Field
The invention relates to the field of triethylamine gas sensors, in particular to a core-shell heterojunction type triethylamine gas sensor and a preparation method thereof.
Background
Since the 60 s of the 20 th century, Seiyama et al developed a combustible gas sensor by using a metal oxide semiconductor for the first time, the metal oxide-based gas sensor developed rapidly, and the sensor of this type had the advantages of wide range of measured gases, low manufacturing cost, simple structure, fast response recovery speed, and the like, and thus, the sensor was widely applied and developed at a high speed in three fields of civil, industrial, and environmental detection. However, such sensors still face the problem of too high (>200 ℃) of the operating temperature, power consumption required by the device, which limits their further applications.
Triethylamine is a highly irritating, toxic and explosive gas, and is widely used in the industrial fields of corrosion prevention, catalysis, organic solvents and the like. Generally, when the concentration of the gas is more than 10ppm, symptoms such as headache, skin injury, edema and the like can be caused, and when the gas is exposed for a long time, serious consequences such as blindness, death and the like can be caused. Therefore, the development of a triethylamine gas sensor with high sensitivity, low power consumption and high stability is urgently needed to realize the detection and analysis of specific concentration.
The prior art discloses methods for preparing various triethylamine sensors. CN106814111A discloses a hollow porous SnO2A microtubule gas-sensitive sensor is prepared by taking alginic acid fiber which is an environment-friendly biomass new material as a template and preparing hollow SnO through ion exchange and high-temperature heat treatment2The micro-tube, based on the gas sensitive device with the structure, has a response of triethylamine with a concentration of 100ppm reaching 49.5 at 280 ℃, and shows a higher gas sensitive characteristic. But the working temperature is still higher, the power consumption is larger, and the special environment application is limited.
CN107337473A discloses an in-situ growth MoO on a ceramic tube3The triethylamine gas sensor of the nano-sheet is mainly prepared by mixing a titanium oxide seed crystal layer and a molybdenum oxide solution and combining a dipping method with high-temperature calcination, and the prepared gas sensor can realize the sensitive detection of triethylamine gas with the concentration of 50ppm, has higher selectivity, but still needs to be reduced in operating temperature and is lack of stability test.
At present, for a traditional gas-sensitive material system, a heterojunction structure is specifically assembled, so that the synergistic effect can be realized, the performance of a gas-sensitive device is improved, the response time is shortened, and the application prospect is wide. CN107356635A discloses a NiO/Fe-based method2O3A triethylamine gas sensor made of a heterostructure composite material. The NiO/Fe is prepared by combining a hydrothermal method and high-temperature annealing treatment2O3Composite sensitive material using NiO/Fe2O3The heterostructure formed between the three elements improves the detection capability of triethylamine, but does not mention low-temperature gas-sensitive performance and repeatability, and cannot judge the specific performance of the triethylamine.
In summary, the existing triethylamine sensor still has the problems of high working temperature, poor stability and the like, so that a new triethylamine gas sensor needs to be developed.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas sensor and a preparation method thereof. According to the invention, the high-sensitivity detection of triethylamine, a toxic and explosive gas, is realized at a temperature close to room temperature (50 ℃), by utilizing the characteristics that the core-shell structure of the gas-sensitive material is high in electron transfer speed and the specific surface area of the graphene material is high, and the gas-sensitive performance can be improved by constructing a heterojunction by using the characteristics of the p-type semiconductor of the boron-doped graphene and shell ZnO; meanwhile, the preparation method is simple and controllable, can realize large-scale production, and has great application prospect.
The invention aims to provide a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
The invention also aims to provide a preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
The invention further aims to provide a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas sensor.
The fourth purpose of the invention is to provide a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material, a preparation method thereof and application of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive sensor.
In order to achieve the above purpose, the invention specifically discloses the following technical scheme:
the gas-sensitive material is prepared by reducing and oxidizing graphene loaded with boron atoms, Au particles and ZnO nanoparticles, wherein the ZnO nanoparticles are coated on the surface of gold particles serving as a core structure, the reducing and oxidizing graphene loaded with the boron atoms is attached to the ZnO nanoparticles, the diameter of the Au particles is 100nm-1.5 mu m, and the diameter of the ZnO nanoparticles is 30-50 nm; preferably, the doping proportion of the boron atoms is controlled to be 3-5% of the total mass of the gas sensitive material by mass fraction.
The invention further discloses a preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material, which comprises the following steps:
(1) preparation of core structure: sputtering and depositing a gold nanoparticle film on a substrate by using a direct-current magnetron sputtering technology, and then annealing in a protective atmosphere to obtain gold particles which are uniformly and independently distributed on the substrate for later use; the gold particles are used as a core structure, so that the gas-sensitive material can still keep good catalytic activity in a low-temperature region.
(2) Preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) so that the zinc film is coated on the surface of the gold particles; then annealing in the air, and oxidizing zinc into zinc oxide to obtain an Au @ ZnO core-shell structure material, wherein the Au @ ZnO core-shell structure material is attached to the surface of the substrate; the core-shell heterostructure can effectively reduce the potential barrier of a grain boundary, improve the transfer speed of electrons and improve the detection sensitivity;
(3) and (3) electrode deposition: depositing a Ti electrode on the surface of the Au @ ZnO core-shell structure obtained in the step (2) by using a standard photoetching process and a metal deposition technology, and then depositing an Au electrode for later use; the introduction of the metal titanium can effectively improve the binding force between the gold electrode and the substrate;
(4) preparing boron-doped graphene: adding graphene oxide and boric acid into a solvent to form a mixed solution of boron-doped graphene oxide, and then carrying out hydrothermal reaction on the mixed solution to obtain a mixed solution of boron-doped reduced graphene oxide for later use;
(5) and (3) uniformly dripping the mixed solution obtained in the step (4) on the surface of the Au @ ZnO core-shell structure material deposited with the Ti and Au electrodes obtained in the step (3) by using a dripping process, and annealing the dried product to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material. The amount of the drop coating mixed liquid can be determined according to the area of the substrate and the required thickness of the boron-doped reduced graphene oxide layer formed after drop coating.
In the step (1), the technical parameters of the direct current magnetron sputtering Au are as follows: the sputtering power is 30W, the pressure is 0.5Pa, the argon flow is 20SCCM, and the deposition time can be set according to the thickness of Au to be deposited.
In the step (1), the protective atmosphere comprises argon or nitrogen.
In the step (1), the substrate comprises SiO grown2Si substrate of insulating layer, wherein, SiO2Layer thickness 300nm, expressed as SiO2(300nm)/Si。
In the step (1), the thickness of the gold nanoparticle film is 5nm-300 nm; preferably 10-50 nm; more preferably 12 nm. The thickness of the gold nanoparticle film can seriously affect the size of the gold nanoparticles formed after annealing, and the excessive thickness of the gold nanoparticle film can cause the overlarge diameter of the gold particles formed after annealing, so that the zinc film can not be coated on the surfaces of the gold particles, and a core-shell structure can not be obtained.
In the step (1), the annealing conditions are as follows: the temperature is 800-: 10 ℃/min.
Preferably, the annealing temperature is 900 ℃ and the annealing time is 10 min. The annealing temperature and time determine the size and crystallization degree of the gold nanoparticles. The structural design that the size of gold particles is larger than that of ZnO particles in the design is influenced, and the gas-sensitive characteristic of the device is influenced.
In the step (1), the diameter of the gold particles formed after annealing is between 100nm and 1.5 mu m, and the gold particles are in (111) preferred orientation.
In the step (2), the technical parameters of depositing the zinc film on the surface of the gold particles by adopting the direct current magnetron sputtering technology are as follows: the sputtering power is 20W, the pressure is 1Pa, the argon flow is 20SCCM, the Zn deposition rate is 0.45nm/s, and the deposition time is 5s-2min, preferably 10s-1 min. More preferably 15 s. The deposition time determines the existence form of zinc oxide, and if the deposition time is too long, tin oxide exists in the form of a thin film, so that the activity of the catalyst is reduced, and the gas-sensitive characteristic of the core-shell structure is reduced and improved.
In the step (2), the annealing conditions are as follows: the temperature is 300 ℃ and 600 ℃, the time is 0.5-3h, and the heating rate is 10 ℃/min.
Preferably, the annealing temperature is 400-600 ℃, and the time is 2 h. The temperature and time of the annealing will ensure that Zn will be fully oxidized to ZnO. If the temperature is too high, gold migration increases to form an alloy of gold and zinc, and if the temperature is too low, it becomes difficult to completely oxidize zinc.
In the step (3), the thickness of the Au electrode is 100nm, and the thickness of the Ti electrode is 20 nm.
In the step (4), the mass ratio of the graphene oxide to the boric acid is 1:1-10: 1; preferably: 7:1.
In the step (4), the solvent is ethanol, and the addition amount of the solvent can disperse graphene oxide and boric acid.
In the step (4), the hydrothermal reaction conditions are as follows: the temperature is 200 ℃, the time is 12h-24h, and after the reaction is finished, the absolute ethyl alcohol and the deionized water are sequentially and repeatedly washed for 5 times for later use.
Preferably, the hydrothermal reaction time is 16 h. The hydrothermal reaction can ensure that boric acid and graphene are uniformly compounded, and can partially reduce graphene oxide.
In the step (5), the drying conditions are as follows: vacuum drying, and baking at 80 deg.C for 1-3 hr.
In the step (5), the annealing conditions are as follows: in a protective atmosphere H with a flow rate of 5SCCM and 100SCCM, respectively2And Ar, and keeping the temperature at 400-500 ℃ for 1-3 h; preferably at 400 ℃ and 500 ℃ for 2 h. Annealing under the condition can realize boron doping, partial reduction treatment can be carried out on the graphene, and active sites are increased.
The boron-doped graphene sheet layer can improve the conductivity of the device, increase the response speed of the device and reduce the working temperature of the device. Meanwhile, the combination of the reduced graphene oxide and the Au @ ZnO core-shell structure can be enhanced through vacuum drying. The response characteristic of the device to triethylamine can be greatly improved by reducing the graphene oxide, and the sensitivity of the device is improved under the combined action of the device and the Au @ ZnO core-shell structure.
The invention further discloses a gas sensor, wherein a gas sensitive material in the sensor is the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas sensitive material prepared by the method. The triethylamine sensor is a resistance type semiconductor gas-sensitive sensor, and the main action principle is that the change of resistance before and after the sensitive unit adsorbs gas is detected in real time.
Finally, the invention also discloses a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material, a preparation method thereof and application of the triethylamine gas-sensitive sensor in the fields of industrial detection and environmental detection.
Compared with the prior art, the invention has the beneficial effects that:
(1) according to the preparation method, the Au @ ZnO core-shell heterojunction type composite structure modified by the boron-doped graphene is prepared by combining a magnetron sputtering technology with an annealing treatment mode, the advantages of high specific surface area of the graphene material and electron transfer of the core-shell structure are fully exerted, the adsorption capacity of gas is enhanced, the working temperature of a device is reduced, and the sensitivity of the device is improved.
(2) According to the invention, the boron-doped reduced graphene oxide is synthesized by a simple hydrothermal synthesis mode. The boron-doped graphene has p-type semiconductor characteristics, forms heterojunction contact with shell ZnO in a core-shell heterostructure, has the advantages of high sensitivity, good repeatability, low detection limit and the like at the working temperature of 50 ℃, and has great application prospects.
(3) The technical process is controllable, the advantages of the traditional gas sensitive material are utilized by virtue of reasonable device structure design, and the high-sensitivity triethylamine sensitive device is obtained by constructing the heterojunction, so that the high-sensitivity triethylamine sensitive device has a high application value.
(4) The technology of the invention can also be expanded to form a gas sensor array, and the process operation is simple and controllable.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.
Fig. 1 is an SEM image and an EDS spectrum of a gas sensitive material prepared in example 1 of the present invention.
FIG. 2 is an X-ray diffraction pattern of a gas-sensitive material prepared in example 1 of the present invention.
FIG. 3 is a graph showing the gas-sensitive characteristics of the gas-sensitive material prepared in example 1 of the present invention with respect to triethylamine at a concentration ranging from 1ppm to 50 ppm.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
As introduced in the background art, the existing triethylamine sensor still has the problems of high working temperature, poor stability and the like, so that the invention provides a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas sensor and a preparation method thereof, and the invention is further described with reference to the accompanying drawings and specific embodiments.
In the following detailed description, the substrate is 1.4cm by 0.7cm (length by width).
Example 1
A preparation method of a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material comprises the following steps:
(1) preparation of core structure: by using DC magnetron sputtering technique on SiO2Sputtering and depositing a gold nanoparticle film with the thickness of 300nm and the same area as the substrate on a (300nm)/Si substrate, wherein the sputtering power is 30W, the pressure is 0.5Pa, the argon flow is 20SCCM, then annealing is carried out at 900 ℃ for 10min under the argon atmosphere, the annealing temperature rise rate is 10 ℃/min, gold particles uniformly and independently distributed on the surface of the substrate are obtained, the diameter of the Au particles is controlled at the level of 300nm, and the gold particles are in (111) preferred orientation;
(2) preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) to coat the zinc film on the surface of the gold particles, wherein the sputtering power is 20W, the pressure is 1Pa, the argon flow is 20SCCM, the deposition rate is 0.45nm/s, and the deposition time is 15 s; then annealing in air at 500 ℃ for 2h, wherein the annealing temperature rise rate is 10 ℃/min, and zinc is oxidized into zinc oxide, so that the Au @ ZnO core-shell structure material is obtained, and the core-shell structure material is attached to the surface of the substrate;
(3) and (3) electrode deposition: respectively depositing Ti (100nm) and Au (20nm) electrodes on the surface of the core-shell structure of the Au @ ZnO obtained in the step (2) by using a standard photoetching process and a metal deposition technology for later use;
(4) preparing boron-doped graphene: graphene oxide and boric acid are mixed according to the mass ratio of 7:1, mixing the solution into an ethanol solution, performing ultrasonic treatment to form a mixed solution of boron-doped graphene oxide, then filling the mixed solution into a reaction kettle, reacting for 16 hours at 200 ℃, and repeatedly cleaning for 5 times according to the sequence of absolute ethyl alcohol and deionized water after the reaction is finished for later use;
(5) measuring a mixed solution (with the concentration of 1mg/ml) of boron-doped reduced graphene oxide with the volume of 0.1ml, and uniformly dripping the mixed solution in the step (4) on the Au @ ZnO core-shell structure deposited with the Ti and Au electrodes in the step (3) by using a dripping process. Baking the product at 80 deg.C for 2H under vacuum, and then introducing protective atmosphere H with flow rate of 5SCCM and 100SCCM respectively2And annealing for 2h at 450 ℃ under Ar to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
Example 2
A preparation method of a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material comprises the following steps:
(1) preparation of core structure: by using DC magnetron sputtering technique on SiO2A gold nanoparticle film with the thickness of 300nm and the same area as the substrate is sputtered and deposited on the (300nm)/Si substrate, the sputtering power is 30W, the pressure is 0.5Pa, and the argon flow is 20 SCCM; then annealing at 950 ℃ for 10min under the argon atmosphere, wherein the annealing temperature rise rate is 10 ℃/min, gold particles which are uniformly and insulatively distributed on the surface of the substrate are obtained, the diameter of the Au particles is controlled at 100nm, and the gold particles are in (111) preferred orientation;
(2) preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) to coat the zinc film on the surface of the gold particles, wherein the sputtering power is 20W, the pressure is 1Pa, the argon flow is 20SCCM, the deposition rate is 0.45nm/s, and the deposition time is 20 s; then annealing in air at 500 ℃ for 3h, wherein the annealing temperature rise rate is 10 ℃/min, and zinc is oxidized into zinc oxide, so that the Au @ ZnO core-shell structure material is obtained, and the core-shell structure material is attached to the surface of the substrate;
(3) and (3) electrode deposition: respectively depositing Ti (100nm) and Au (20nm) electrodes on the surface of the core-shell structure of the Au @ ZnO obtained in the step (2) by using a standard photoetching process and a metal deposition technology, and repeatedly cleaning the electrodes for 5 times according to the sequence of absolute ethyl alcohol and deionized water after the reaction is finished for later use;
(4) preparing boron-doped graphene: mixing graphene oxide and boric acid according to the mass ratio of 6: 1, mixing the mixed solution into an ethanol solution, performing ultrasonic treatment to form a mixed solution of boron-doped graphene oxide, then filling the mixed solution into a reaction kettle, and reacting at 200 ℃ for 24 hours for later use;
(5) measuring a mixed solution (1mg/ml) of boron-doped reduced graphene oxide with the volume of 0.3ml, and uniformly dripping the mixed solution in the step (4) on the Au @ ZnO core-shell structure deposited with the Ti and Au electrodes in the step (3) by using a dripping process. Baking the product at 80 deg.C for 2H under vacuum, and then introducing protective atmosphere H with flow rate of 5SCCM and 100SCCM respectively2And annealing for 2 hours at 400 ℃ under Ar to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
Example 3
A preparation method of a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material comprises the following steps:
(1) preparation of core structure: by using DC magnetron sputtering technique on SiO2A gold nanoparticle film with the thickness of 300nm and the same area as the substrate is sputtered and deposited on the (300nm)/Si substrate, the sputtering power is 30W, the pressure is 0.5Pa, and the argon flow is 20 SCCM; then annealing at 1000 ℃ for 10min under the argon atmosphere, wherein the annealing temperature rise rate is 10 ℃/min, so that gold particles uniformly and independently distributed on the surface of the substrate are obtained, the diameter of the Au particles is controlled at 100nm, and the gold particles are in (111) preferred orientation;
(2) preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) to coat the zinc film on the surface of the gold particles, wherein the sputtering power is 20W, the pressure is 1Pa, the argon flow is 20SCCM, the deposition rate is 0.45nm/s, and the deposition time is 2 min; then annealing in air at 400 ℃ for 2h, wherein the annealing temperature rise rate is 10 ℃/min, and zinc is oxidized into zinc oxide, so that the Au @ ZnO core-shell structure material is obtained, and the core-shell structure material is attached to the surface of the substrate;
(3) and (3) electrode deposition: respectively depositing Ti (100nm) and Au (20nm) electrodes on the surface of the Au @ ZnO core-shell structure obtained in the step (2) by using a standard photoetching process and a metal deposition technology, and repeatedly cleaning the electrodes for 5 times according to the sequence of absolute ethyl alcohol and deionized water after the reaction is finished for later use;
(4) preparing boron-doped graphene: mixing graphene oxide and boric acid according to the mass ratio of 6: 1, mixing the mixed solution into an ethanol solution, performing ultrasonic treatment to form a mixed solution of boron-doped graphene oxide, then filling the mixed solution into a reaction kettle, and reacting for 12 hours at 200 ℃ for later use;
(5) measuring a mixed solution (1mg/ml) of boron-doped reduced graphene oxide with the volume of 0.4ml, and uniformly dripping the mixed solution in the step (4) on the Au @ ZnO core-shell structure deposited with the Ti and Au electrodes in the step (3) by using a dripping process. Baking the product at 80 deg.C for 2H under vacuum, and then introducing protective atmosphere H with flow rate of 5SCCM and 100SCCM respectively2And annealing for 2 hours at 500 ℃ under Ar to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
Example 4
A preparation method of a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material comprises the following steps:
(1) preparation of core structure: by using DC magnetron sputtering technique on SiO2A gold nanoparticle film with the thickness of 300nm and the same area as the substrate is sputtered and deposited on the (300nm)/Si substrate, the sputtering power is 30W, the pressure is 0.5Pa, and the argon flow is 20 SCCM; then, annealing at 1050 ℃ for 5min in a nitrogen atmosphere, wherein the annealing temperature rise rate is 10 ℃/min, so that gold particles uniformly and independently distributed on the substrate are obtained, the diameter of the Au particles is controlled at 100nm, and the gold particles are in (111) preferred orientation;
(2) preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) to coat the zinc film on the surface of the gold particles, wherein the sputtering power is 20W, the pressure is 1Pa, the argon flow is 20SCCM, the deposition rate is 0.45nm/s, and the deposition time is 1 min; then annealing in the air at 600 ℃ for 0.5h at the annealing temperature rise rate of 10 ℃/min, and oxidizing zinc into zinc oxide to obtain an Au @ ZnO core-shell structure material, wherein the core-shell structure material is attached to the surface of the substrate;
(3) and (3) electrode deposition: respectively depositing Ti (100nm) and Au (20nm) electrodes on the surface of the Au @ ZnO core-shell structure obtained in the step (2) by using a standard photoetching process and a metal deposition technology, and repeatedly cleaning the electrodes for 5 times according to the sequence of absolute ethyl alcohol and deionized water after the reaction is finished for later use;
(4) preparing boron-doped graphene: graphene oxide and boric acid are mixed according to the mass ratio of 1:1, mixing the mixed solution into an ethanol solution, performing ultrasonic treatment to form a mixed solution of boron-doped graphene oxide, then filling the mixed solution into a reaction kettle, and reacting for 16 hours at 200 ℃ for later use;
(5) measuring a mixed solution (1mg/ml) of boron-doped reduced graphene oxide with the volume of 0.6ml, and uniformly dripping the mixed solution in the step (4) on the Au @ ZnO core-shell structure deposited with the Ti and Au electrodes in the step (3) by using a dripping process. Baking the product at 80 deg.C for 3H under vacuum, and then introducing protective atmosphere H with flow rate of 5SCCM and 100SCCM respectively2And annealing for 2 hours at 500 ℃ under Ar to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
Example 5
A preparation method of a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material comprises the following steps:
(1) preparation of core structure: by using DC magnetron sputtering technique on SiO2A gold nanoparticle film with the thickness of 300nm and the same area as the substrate is sputtered and deposited on the (300nm)/Si substrate, the sputtering power is 30W, the pressure is 0.5Pa, and the argon flow is 20 SCCM; then annealing at 800 ℃ for 30min in a nitrogen atmosphere, wherein the annealing temperature rise rate is 10 ℃/min, so that gold particles uniformly and independently distributed on the substrate are obtained, the diameter of the Au particles is controlled at 1500nm, and the gold particles are in (111) preferred orientation;
(2) preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) to coat the zinc film on the surface of the gold particles, wherein the sputtering power is 20W, the pressure is 1Pa, the argon flow is 20SCCM, the deposition rate is 0.45nm/s, and the deposition time is 10 s; then annealing in air at 300 ℃ for 3h, wherein the annealing temperature rise rate is 10 ℃/min, and oxidizing zinc into zinc oxide to obtain an Au @ ZnO core-shell structure material, wherein the core-shell structure material is attached to the surface of the substrate;
(3) and (3) electrode deposition: respectively depositing Ti (100nm) and Au (20nm) electrodes on the surface of the Au @ ZnO core-shell structure obtained in the step (2) by using a standard photoetching process and a metal deposition technology for later use;
(4) preparing boron-doped graphene: mixing graphene oxide and boric acid according to the mass ratio of 10:1, mixing the solution with an ethanol solution, performing ultrasonic treatment to form a mixed solution of boron-doped graphene oxide, then filling the mixed solution into a reaction kettle, reacting for 18 hours at 200 ℃, and repeatedly cleaning for 5 times according to the sequence of absolute ethyl alcohol and deionized water after the reaction is finished for later use;
(5) and (3) measuring a mixed solution (1mg/ml) of boron-doped reduced graphene oxide with the volume of 0.8ml, and uniformly dripping the mixed solution in the step (4) on the Au @ ZnO core-shell structure deposited with the Ti and Au electrodes in the step (3) by using a dripping process. Baking the product at 80 deg.C for 3H under vacuum, and then introducing protective atmosphere H with flow rate of 5SCCM and 100SCCM respectively2And annealing for 2 hours at 500 ℃ under Ar to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
Example 6
A preparation method of a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material comprises the following steps:
(1) preparation of core structure: by using DC magnetron sputtering technique on SiO2A gold nanoparticle film with the thickness of 300nm and the same area as the substrate is sputtered and deposited on the (300nm)/Si substrate, the sputtering power is 30W, the pressure is 0.5Pa, and the argon flow is 20 SCCM; then annealing at 800 deg.C for 30min in nitrogen atmosphere at an annealing temperature rise rate of 10 deg.C/min to obtain gold particles uniformly and independently distributed on the substrate, and controlling the diameter of Au particlesOn the order of 1500nm, and the gold particles are in a (111) preferred orientation;
(2) preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) to coat the zinc film on the surface of the gold particles, wherein the sputtering power is 20W, the pressure is 1Pa, the argon flow is 20SCCM, the deposition rate is 0.45nm/s, and the deposition time is 5 s; then annealing in air at 500 ℃ for 2h, wherein the annealing temperature rise rate is 10 ℃/min, and zinc is oxidized into zinc oxide, so that the Au @ ZnO core-shell structure material is obtained, and the core-shell structure material is attached to the surface of the substrate;
(3) and (3) electrode deposition: respectively depositing Ti (100nm) and Au (20nm) electrodes on the surface of the Au @ ZnO core-shell structure material obtained in the step (2) by using a standard photoetching process and a metal deposition technology, and repeatedly cleaning the Au @ ZnO core-shell structure material for 5 times according to the sequence of absolute ethyl alcohol and deionized water after the reaction is finished for later use;
(4) preparing boron-doped graphene: mixing graphene oxide and boric acid according to the mass ratio of 3: 1, mixing the mixed solution into an ethanol solution, performing ultrasonic treatment to form a mixed solution of boron-doped graphene oxide, then filling the mixed solution into a reaction kettle, and reacting for 20 hours at 200 ℃ for later use;
(5) measuring a mixed solution (1mg/ml) of boron-doped reduced graphene oxide with the volume of 1ml, and uniformly dripping the mixed solution in the step (4) on the Au @ ZnO core-shell structure deposited with the Ti and Au electrodes in the step (3) by using a dripping process. Baking the product at 80 deg.C for 1.5H under vacuum, and then introducing protective atmosphere H with flow rate of 5SCCM and 100SCCM respectively2And annealing for 2h at 450 ℃ under Ar to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
And (3) performance testing:
fig. 3 is a gas-sensitive characteristic test chart of the gas-sensitive material prepared in embodiment 1 of the present invention for triethylamine, where the operating temperature is 50 ℃, and the triethylamine concentration is 1ppm to 50ppm, and it can be seen from the chart that, at a concentration of 30ppm, the gas-sensitive response sensitivity of the sensor prepared in the present invention for triethylamine reaches 52%, the minimum detected concentration value reaches 1ppm, and the fluctuation degree of the sensitivity of the tested cycling stability is lower than 5%, compared with the similar sensors, the device has low operating temperature and good stability, and can implement high-sensitivity detection for the toxic and explosive gas triethylamine at near room temperature (50 ℃).
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (12)
1. A preparation method of a boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material is characterized by comprising the following steps: the method comprises the following steps:
(1) preparation of core structure: sputtering and depositing a gold nanoparticle film on a substrate by using a direct-current magnetron sputtering technology, and then annealing in a protective atmosphere to obtain gold particles which are uniformly and independently distributed on the substrate for later use; the gold particles are used as a core structure, so that the gas-sensitive material can still keep good catalytic activity in a low-temperature region;
(2) preparation of the shell structure: continuously utilizing a direct current magnetron sputtering technology to deposit a zinc film on the surface of the gold particles in the step (1) so that the zinc film is coated on the surface of the gold particles; then annealing in the air, and oxidizing zinc into zinc oxide to obtain an Au @ ZnO core-shell structure material, wherein the Au @ ZnO core-shell structure material is attached to the surface of the substrate; the core-shell heterostructure can effectively reduce the potential barrier of a grain boundary, improve the transfer speed of electrons and improve the detection sensitivity;
(3) and (3) electrode deposition: depositing a Ti electrode on the surface of the Au @ ZnO core-shell structure material obtained in the step (2) by using a standard photoetching process and a metal deposition technology, and then depositing an Au electrode for later use; the introduction of the metal titanium can effectively improve the binding force between the gold electrode and the substrate;
(4) preparing boron-doped graphene: adding graphene oxide and boric acid into a solvent to form a mixed solution of boron-doped graphene oxide, and then carrying out hydrothermal reaction on the mixed solution to obtain a mixed solution of boron-doped reduced graphene oxide for later use;
(5) and (3) uniformly dripping the mixed solution obtained in the step (4) on the surface of the Au @ ZnO core-shell structure material deposited with the Ti and Au electrodes obtained in the step (3) by using a dripping process, and annealing the dried product to obtain the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material.
2. The preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material according to claim 1, characterized by comprising the following steps: in the step (1), the technical parameters of the direct current magnetron sputtering Au are as follows: the sputtering power is 30W, the pressure is 0.5Pa, the argon flow is 20SCCM, and the deposition time can be set according to the thickness of Au to be deposited; the protective atmosphere comprises argon or nitrogen.
3. The preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material according to claim 1, characterized by comprising the following steps: in the step (1), the thickness of the gold nanoparticle film is 5nm-300 nm; in the step (1), the annealing conditions are as follows: the temperature is 800-: 10 ℃/min.
4. The preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material according to claim 1, characterized by comprising the following steps: in the step (1), the thickness of the gold nanoparticle film is 10-50 nm; the annealing conditions are as follows: the annealing temperature is 900 ℃ and the annealing time is 10 min.
5. The preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material according to claim 1, characterized by comprising the following steps: in the step (1), the diameter of the gold particles formed after annealing is between 100nm and 1.5 mu m, and the gold particles are in (111) preferred orientation;
in the step (2), the technical parameters of depositing the zinc film on the surface of the gold particles by adopting the direct current magnetron sputtering technology are as follows: sputtering power is 20W, pressure intensity is 1Pa, argon flow is 20SCCM, Zn deposition rate is 0.45nm/s, and deposition time is 5s-2 min;
in the step (2), the annealing conditions are as follows: the temperature is 300 ℃ and 600 ℃, the time is 0.5-3h, and the heating rate is 10 ℃/min.
6. The preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material according to claim 1, characterized by comprising the following steps: in the step (2), the annealing conditions are as follows: the annealing temperature is 400-600 ℃, and the time is 2 h.
7. The preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material according to claim 1, characterized by comprising the following steps: in the step (3), the thickness of the Au electrode is 100nm, and the thickness of the Ti electrode is 20 nm;
in the step (4), the mass ratio of the graphene oxide to the boric acid is 1:1-10: 1;
in the step (4), the hydrothermal reaction conditions are as follows: the temperature is 200 ℃, the time is 12h-24h, and after the reaction is finished, the absolute ethyl alcohol and the deionized water are sequentially and repeatedly washed for 5 times for later use.
8. The preparation method of the boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material according to claim 1, characterized by comprising the following steps: in the step (5), the drying conditions are as follows: vacuum drying, and baking at 80 deg.C for 1-3 hr;
in the step (5), the annealing conditions are as follows: in a protective atmosphere H with a flow rate of 5SCCM and 100SCCM, respectively2And Ar, and keeping the temperature at 400-500 ℃ for 1-3 h.
9. The boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material prepared by the preparation method of any one of claims 1 to 8 is characterized in that: the gas sensitive material consists of reduced graphene oxide loaded with boron atoms, Au particles and ZnO nanoparticles, wherein the ZnO nanoparticles are coated on the surfaces of gold particles serving as a core structure, and the reduced graphene oxide loaded with the boron atoms is attached to the ZnO nanoparticles.
10. The boron-doped graphene modified Au @ ZnO core-shell heterojunction triethylamine gas-sensitive material of claim 9, which is characterized in that: the diameter of the Au particles is 100nm-1.5 mu m, the diameter of the ZnO nanoparticles is 30-50nm, and the doping proportion of the boron atoms is controlled to be 3-5% of the total mass of the gas sensitive material by mass fraction.
11. A gas sensor, characterized in that: the gas-sensitive material in the sensor is the triethylamine gas-sensitive material as claimed in claim 9.
12. Use of the gas sensor of claim 11 in the fields of industrial detection, environmental detection.
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