WO2023231191A1 - Sno2/nio/graphene ternary composite material, and preparation method therefor and application thereof - Google Patents

Sno2/nio/graphene ternary composite material, and preparation method therefor and application thereof Download PDF

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WO2023231191A1
WO2023231191A1 PCT/CN2022/114144 CN2022114144W WO2023231191A1 WO 2023231191 A1 WO2023231191 A1 WO 2023231191A1 CN 2022114144 W CN2022114144 W CN 2022114144W WO 2023231191 A1 WO2023231191 A1 WO 2023231191A1
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nio
sno
composite material
graphene
gas
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Chinese (zh)
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王艳艳
黄曼曼
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苏州大学
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    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/182—Graphene
    • C01B32/198—Graphene oxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G19/00—Compounds of tin
    • C01G19/02—Oxides
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    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/04—Oxides; Hydroxides
    • G—PHYSICS
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    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
    • G01N27/127—Composition of the body, e.g. the composition of its sensitive layer comprising nanoparticles
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    • C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/32—Spheres
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
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    • C01—INORGANIC CHEMISTRY
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    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • 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
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention belongs to gas-sensitive material technology, and specifically relates to a SnO 2 /NiO/graphene ternary three-dimensional composite material and its preparation method and application.
  • Gas-sensitive materials determine the quality of sensors and are the key to sensor research.
  • graphene has attracted widespread attention due to its extremely high electron mobility and large specific surface area.
  • graphene-sensitive materials have bottlenecks such as low response sensitivity, slow response, and poor selectivity.
  • combining graphene with metal oxides to form heterostructures is one of the effective ways to solve this problem.
  • gas sensing performance can be improved by designing different new structures.
  • single graphene or metal oxide gas sensors have shortcomings such as low gas-sensing response and high operating temperature, which are often improved by compounding graphene with metal oxides.
  • the gas-sensing response performance of existing composite gas-sensing materials needs to be improved.
  • the present invention prepares graphene oxide nanosieve HGO by etching GO with MnO 2 under acidic conditions, and obtains SnO 2 /NiO/HrGO ternary composite material, which exhibits excellent NO 2 gas-sensing properties.
  • AFM testing the morphology and structure of GO and HGO were compared.
  • HGO has a slightly smaller sheet diameter than GO.
  • SnO 2 /NiO/rGO the same testing and characterization methods were adopted for SnO 2 /NiO/HrGO.
  • the response of the SnO 2 /NiO/HrGO ternary composite material to 1 ppm NO 2 is 23.4%, which is significantly higher than the existing composite sensing device.
  • the present invention adopts the following technical solution: a SnO 2 /NiO/graphene ternary composite material, including nano SnO 2 , nano NiO and porous graphene; specifically, nano SnO 2 , nano NiO, and graphene oxide nano sieve are mixed After grinding and calcining, SnO 2 /NiO/graphene ternary composite material is obtained.
  • a gas sensor device includes interdigital electrodes and a gas-sensitive material.
  • the gas-sensitive material is the above-mentioned SnO 2 /NiO / graphene ternary composite material. As common sense, it also includes leads, bases, etc.
  • the creativity of the present invention lies in The above-mentioned SnO 2 /NiO/graphene ternary composite material is a gas-sensitive material, and other components used in the device are all existing products.
  • the nano NiO solution, the graphene oxide nanosieve solution, and the nano SnO 2 solution are stirred and mixed and then centrifuged, and the precipitates are collected, dried, ground, and then calcined to obtain the SnO 2 /NiO/graphene ternary composite material.
  • the nano-NiO solution and the graphene oxide nanosieve solution are added to the nano-SnO 2 solution in sequence, stirred and mixed, and then centrifuged. The precipitate is collected, dried, ground, and then calcined to obtain the SnO 2 /NiO/graphene ternary composite material.
  • the mass ratio of nano-SnO 2 , nano-NiO, and graphene oxide nanosieve is (1-20): (1-20):1, preferably (2-10): (2-5):1, and more preferably ( 5 ⁇ 10):2:1, such as 10:2:1, 5:2:1. Calcining is performed in air at 180-220°C for 1.5-3 hours.
  • potassium permanganate and graphene oxide solution are mixed, then heated by microwave, and treated with hydrochloric acid to obtain graphene oxide nanosieve;
  • the power of microwave heating is 500-1000W, and the time is 3-6 minutes, preferably The power of microwave heating is 600 ⁇ 800W and the time is 4 ⁇ 5 minutes; during hydrochloric acid treatment, the temperature is 60°C ⁇ 80°C and the time is 2h ⁇ 4h.
  • nickel salt and citrate are used as raw materials, dried and calcined after hydrothermal reaction to obtain nano NiO; preferably, the hydrothermal reaction is 170°C to 190°C for 15 to 18 hours; the calcination is 370°C to 190°C. Calculate at 420°C for 2h ⁇ 4h.
  • polyvinylpyrrolidone and tin salt are used as raw materials, and after solvothermal reaction, they are dried and calcined to obtain nano-SnO 2 ; preferably, the solvothermal reaction is at 170°C to 190°C for 2 to 4 hours; the calcination is at 470°C Calcined at ⁇ 520°C for 1h ⁇ 3h.
  • the present invention adopts an oxidative etching method to prepare graphene oxide nanosieve HGO, and constructs a two-dimensional reduced graphene oxide nanosieve HrGO supporting a ternary composite structure of metal oxide SnO 2 nanospheres and NiO nanoflowers. Based on this structure, the NO 2 sensing performance of the SnO 2 /NiO/HrGO ternary composite sensor was studied in depth, and the test results of the SnO 2 /NiO/rGO ternary composite material were compared and analyzed. The gas-sensing response of SnO 2 /NiO/HrGO ternary composite devices is significantly improved.
  • the invention discloses the application of the above-mentioned SnO2 /NiO/graphene ternary composite material or gas sensor device in nitrogen dioxide detection, or the use of the above-mentioned SnO2 /NiO/graphene ternary composite material in the preparation of gas sensors for nitrogen dioxide detection. Applications in Materials.
  • the present invention is based on the Hummers method for preparing graphene oxide (GO) and surface-controlled semiconductor sensitive materials, and adopts solvothermal, oxidative etching, high-temperature annealing and other methods to obtain tin oxide/nickel oxide/reduced graphene oxide nanosieve (SnO 2 /NiO/HrGO) ternary composite material, and its room temperature gas-sensing properties for NO 2 were studied.
  • the specific research results are as follows: After structural control, a new reduced graphene oxide nanosieve (HrGO) was obtained as the substrate, loaded with The ternary composite material of nickel oxide nanoflowers and tin oxide nanospheres shows better gas sensing performance for NO 2 gas.
  • Graphene oxide nanosieve was prepared using oxidative etching method. Then, the SnO 2 /NiO/HrGO ternary composite material is obtained through high-temperature annealing and reduction.
  • the gas sensing test results show that the highest response value of SnO 2 /NiO/HrGO ternary composite material to 1 ppm is 23.4%, which is 1.7 for SnO 2 /HrGO binary composite material, NiO/HrGO binary composite material and single HrGO respectively. , 2 and 3.2 times.
  • the mass ratio of SnO 2 to NiO increases, the gas sensing response of SnO 2 /NiO/HrGO first increases and then decreases.
  • the response value of HrGO series products is higher than that of rGO series.
  • Figure 1 is the SEM image of NiO nanoflowers.
  • Figure 2 is an SEM image of SnO2 nanospheres.
  • Figure 3 shows the AFM image of HGO.
  • Figure 4 shows the XRD patterns of HGO and ternary composite SnO 2 /NiO/HrGO.
  • Figure 5 shows the XPS (a) full spectrum and (b) C 1s fine spectrum of HGO.
  • Figure 6 shows the XPS fine spectrum of the ternary composite SnO 2 /NiO/HrGO: (a) C 1s; (b) O 1s; (c) Ni 2p; (d) Sn 3d.
  • Figure 7 shows the gas-sensitive response curves of SnO 2 /NiO/HrGO, SnO 2 /HrGO, NiO/HrGO and HrGO to 1 ppm NO 2 .
  • Figure 8 shows the gas-sensitive response curve of SnO 2 /NiO/HrGO ternary composite sensor to different concentrations of NO 2 .
  • Figure 9 shows the real-time gas sensing response curves of (a) SnO 2 /NiO/HrGO with different mass ratios to 1 ppm NO 2 .
  • Figure 10 is a line chart of the gas sensing response values of SnO 2 /NiO/rGO and SnO 2 /NiO/HrGO.
  • Figure 11 shows the gas-sensitive response curve of SnO 2 /NiO/rGO ternary composite sensor to different concentrations of NO 2 .
  • Figure 12 is a histogram of the gas-sensitive response values of the SnO 2 /NiO/HrGO ternary composite sensor to different gases.
  • the present invention uses two-dimensional graphene and metal oxides with two unique shapes, spherical and flower-shaped, to form a ternary composite structure model of PNP heterojunction.
  • the heterostructure of the contact surface is used to significantly improve the NOx of the ternary composite material.
  • the combination of the three morphologies of nanospheres, nanoflowers and nanosheets allows SnO2 nanospheres and NiO nanoflowers to be dispersed between graphene sheets, effectively reducing the stacking of graphene nanosheets and establishing electron transport between composite materials. Transport channels increase gas adsorption sites, and abundant oxygen defects can improve the sensitivity of composite materials to target gases.
  • the invention prepares SnO 2 /NiO/graphene ternary composite material and obtains excellent gas-sensitive response characteristics.
  • the present invention adopts annealing reduction method to prepare SnO 2 /NiO/HrGO ternary composite material.
  • SnO 2 and NiO powders were added to ethanol respectively to obtain a uniform solution.
  • the milky white SnO 2 solution was then added dropwise to the green NiO solution, and then the HGO solution was added dropwise.
  • the product was collected by centrifugation and dried in a 60°C oven; the solid was then ground to obtain SnO 2 /
  • the NiO/HGO powder is then put into a tube furnace, calcined in air at 200°C for 2 hours for reduction, and finally the SnO 2 /NiO/HrGO ternary composite material is obtained.
  • An atomic force microscope was used to scan the morphology of HrGO, and the composite SnO 2 /NiO/HrGO was conventionally characterized by XRD, Raman, XPS, and FTIR.
  • the graphene oxide of the present invention is prepared by referring to the conventional Hummers method.
  • the principle is to use strong acid and strong oxidant to oxidize and intercalate natural graphite flakes to increase the interlayer spacing of graphite flakes, and then use thermal expansion to further increase the interlayer spacing and increase the number of layers.
  • mechanical stirring and ultrasonic peeling were combined to separate the graphite sheets, and finally graphene oxide (GO) was successfully prepared.
  • the preparation process is as follows: 1) Weigh 2 g of natural graphite (500 mesh), and combine it with Mix 50 ml of concentrated sulfuric acid in a 250 ml beaker and stir for 30 minutes. Add 1 g of sodium nitrate and stir for 2 hours under ice bath. Add 7.3 g of potassium permanganate in three batches, and then react. The solution was stirred in a 35°C water bath for 2 hours to further complete the oxidation intercalation; then 150 ml of deionized water, stir for 30 minutes to make the solution exothermic, and use thermal expansion to further increase the interlayer spacing; then add 55 ml of 4% hydrogen peroxide solution dropwise to the mixed solution and stir for 30 minutes to further oxidize and consume excess hydrogen peroxide.
  • Example 1 Preparation of NiO nanoflowers: Use solvothermal method to prepare NiO nanoflowers.
  • the specific operation process is as follows: (1) Weigh 1.5 g of nickel nitrate hexahydrate (Ni(NO 3 ) 2 . 6H 2 O) In the beaker, add 30 mL of deionized water to obtain solution A; weigh 0.5 g of sodium citrate dihydrate (Na 3 C 6 H 5 O 7 . 2H 2 O), and add 30 mL of deionized water to obtain solution B; (2) Add solution B dropwise to the stirring solution A to obtain a transparent light green mixed solution.
  • Example 2 Preparation of SnO 2 nanospheres: SnO 2 nanospheres with a particle size of about 500 nm were obtained using a solvothermal method combined with high-temperature annealing.
  • the specific preparation method is as follows: (1) Add 0.5 g polyvinylpyrrolidone (PVP), 0.25 g tin tetrachloride pentahydrate (SnCl 4 . 5H 2 0), and 60 mL methanol into a polytetrafluoroethylene autoclave, and place it in a polytetrafluoroethylene autoclave.
  • PVP polyvinylpyrrolidone
  • SnCl 4 . 5H 2 0 0.25 g tin tetrachloride pentahydrate
  • 60 mL methanol into a polytetrafluoroethylene autoclave, and place it in a polytetrafluoroethylene autoclave.
  • FIG. 1 is an SEM image of SnO 2 nanospheres.
  • the diameter of SnO 2 nanospheres is about 0.5 ⁇ m.
  • the SnO 2 nanospheres have uniform particle size, complete morphology, and no impurity particles.
  • Example Preparation of graphene oxide nanosieve The preparation of graphene oxide nanosieve is based on the etching of GO by MnO 2 under acidic conditions.
  • the specific preparation method is as follows: (1) Weigh 0.2 g KMnO 4 Add to 100 ml of GO aqueous solution with a concentration of 1 mg/ml and stir magnetically for 20 minutes to obtain a dark purple solution; (2) Move the above dark purple solution into a conventional household microwave oven (700 W) and heat at high heat for 5 minutes; (3) ) After the microwave reaction, the product is naturally cooled to room temperature, then taken out, centrifuged and washed 5 times with deionized water; (4) The washed precipitate is moved into a round-bottomed flask, hydrochloric acid (37wt%) is added to cover the product, and then placed in a water bath Treat in a water bath at 70°C for 3 hours in the container, during which magnetic stirring is continued; (5) The product after hydrochloric acid treatment
  • Example 4 Preparation of SnO 2 /NiO/HrGO ternary composite material: The response speed and sensitivity of the sensor device are closely related to the structural size, specific surface area, and heterogeneity of the active material. SnO 2 /NiO/HrGO ternary composite materials were prepared by annealing reduction.
  • the solid matter is ground to obtain SnO 2 /NiO/HGO powder, which is then placed in a tube furnace, calcined in air at 200°C for 2 hours for reduction, and finally the SnO 2 /NiO/HrGO ternary composite material is obtained.
  • the XRD spectrum of SnO 2 /NiO/HrGO ternary composite material and HGO is shown in Figure 4.
  • Each diffraction plane has been marked in the figure, and there are no characteristic peaks of impurities, and no other phases related to nickel, tin or tin-nickel compounds were observed, which indicates that the SnO 2 /NiO/HrGO ternary composite material was successfully synthesized.
  • the (001) and (004) diffraction planes located at 12.23° and 42.59° belong to graphene oxide, and the (002) peak located at 20° belongs to reduced graphene oxide; the ternary composite material contains (002) of reduced graphene oxide. ) peak, this important change indicates that the composite material is successfully reduced.
  • Figure 5 shows the XPS full spectrum and C 1s fine spectrum of graphene oxide nanosieve.
  • the peaks corresponding to C and O can be clearly observed and no other impurity peaks are seen.
  • Figure 6 shows the fine spectra of C 1s, O 1s, Ni 2p and Sn 3d of SnO 2 /NiO/HrGO ternary composite material under narrow scanning.
  • the surface chemical element composition and electronic state of the SnO 2 /NiO/HrGO ternary composite material were analyzed through XPS characterization.
  • O 1s is composed of components in three different chemical states: O Lattice , O V , and O- x.
  • NiO nanoflowers Weigh 0.02g of NiO nanoflowers and add 50 ml of ethanol into the beaker to obtain a green NiO solution; then add 10 ml of HGO aqueous solution with a concentration of 1 mg/ml dropwise into the above green NiO solution, and stir for 15 minutes as usual; then stir at 4000 Centrifuge at 100 rpm/min, collect the precipitate and dry it in a 60°C oven to obtain a solid. Grind the solid to obtain NiO/HGO powder, then put it into a tube furnace in the air and calcine at 200°C for 2 hours for reduction. Finally, NiO/HrGO composite material was obtained.
  • interdigital electrodes can be used as physical carrier components to supply voltage to the attached and connected gas-sensitive materials.
  • the interdigital electrode of the gas sensor of the present invention is an existing product. It is manufactured based on silicon technology and adopts traditional micro-machining technology.
  • the preparation process is as follows: putting the cleaned silicon wafer into a mixture of concentrated H 2 SO 4 and H 2 O 2 In the mixed solution, treat it at 90°C for half an hour to obtain a silicon wafer substrate with a hydrophilic surface. After washing and drying, spin-coat photoresist on the surface, put a conventional interdigitated mask on for exposure and development, and then paint on the substrate. Gold was sputtered, and finally the photoresist was ultrasonically peeled off to prepare interdigital electrodes. The distance between the interdigitated electrodes prepared was 10 microns, 10 microns wide, and 600 microns long.
  • the gas-sensitive material was changed as a control: the SnO 2 /NiO/HrGO ternary composite material was changed to SnO 2 /NiO/HGO powder, and the rest remained unchanged to obtain the SnO 2 /NiO/HGO gas sensor. .
  • the SnO 2 /NiO/HrGO ternary composite material is changed to SnO 2 /HrGO composite material, and the other components remain unchanged to obtain a SnO 2 /HGO gas sensor.
  • HGO aqueous solution with a concentration of 1 mg/ml was dropped into the effective contact area of the interdigital electrode. After it was naturally dried, it was placed in a tube furnace and calcined in the air at 200°C for 2 hours for reduction, and finally the HrGO gas sensor was obtained. .
  • Embodiment 6 Gas-sensitive sensing test: According to the existing technology, a gas-sensitive testing system was built using the Agilent B1500A semiconductor tester. The test system consists of two parts: gas supply and data acquisition. The gas supply system uses compressed air as the background gas and NO 2 as the target gas. The two gases are first fully mixed in the mixing chamber and then passed into the test chamber where the device is located.
  • the gas sensor Place the gas sensor into the test chamber and connect the two pins to the Agilent tester. Before testing, switch to the IV mode of the tester to check whether the device is conducting. Then, the background gas is introduced for a period of time to remove the residual NO 2 gas, and the background gas is continuously introduced. The test mode is adjusted to I/VT, and the voltage is set to 0.5 V. At this time, the dynamic curve of the device resistance can be observed. After obtaining a stable baseline, the target gas NO 2 is introduced, and the required NO 2 concentration C n is determined by adjusting the NO 2 flow rate F n and the background gas flow rate Fa . After the resistance is stable and lasts for a suitable period of time, all gases can be turned off. When the gas sensitivity curve reaches stability again, a complete cycle of gas response is obtained. The response percentage is the ratio of the resistance change to the initial resistance and is calculated as follows: .
  • the improved graphene nanosieves are mostly small flake structures and have porous structures.
  • SnO 2 /NiO/HrGO SnO 2 /NiO/HGO was tested in this section /NO 2 gas sensing performance of HrGO.
  • Figure 7 shows the gas-sensitive response curves of SnO 2 /NiO/HrGO, SnO 2 /HrGO, NiO/HrGO and HrGO to 1 ppm NO 2 .
  • the gas sensing response values of SnO 2 /NiO/HrGO, SnO 2 /HrGO, NiO/HrGO and HrGO are 23.4%, 13.9%, 11.8% and 7.4% respectively.
  • the gas-sensing response of SnO 2 /NiO/HrGO ternary composite material is significantly higher than that of SnO 2 /HrGO binary composite material, NiO/HrGO binary composite material and single HrGO material, effectively demonstrating the fast response rate and stable response state of the present invention.
  • the response of the existing SnO 2 -CuO/rGO sensor to 5 ppm NO 2 is only 18%; the device with a single metal oxide has basically no response at room temperature.
  • Figure 8 shows the gas-sensitive response curves of the SnO 2 /NiO/HrGO ternary composite sensor to 200 ppb, 500 ppb, and 1 ppm NO 2.
  • the gas-sensitive response values are 16.9%, 18.9%, and 23.4% respectively.
  • There are obvious changes in the response of each concentration which shows that SnO 2 /NiO/HrGO has excellent resolving power for low concentrations of NO 2 and is suitable for applications where the detection limit of NO 2 concentration is low.
  • Example 7 Based on the preparation method of Example 4, change the input of SnO 2 /NiO/HrGO, that is, keep the amount of HGO aqueous solution unchanged, change the amount of SnO 2 /NiO, and keep the rest unchanged, to obtain different raw material ratios.
  • the SnO 2 /NiO/HrGO ternary composite material was used for gas testing in Example 6.
  • Figure 9 explores the impact of different compound ratios on the sensor performance of the SnO 2 /NiO/HrGO ternary composite material.
  • Example 8 First, weigh 0.1g SnO 2 nanospheres and 0.02g NiO nanoflowers into a beaker and add 50 ml of ethanol respectively to obtain a milky white SnO 2 solution and a green NiO solution; then add the milky white SnO 2 solution drop by drop.
  • Figure 10 is a comparison chart of the gas sensing responses of SnO 2 /NiO/HrGO and SnO 2 /NiO/rGO.
  • the NO 2 concentration is all 1 ppm. It can be observed that as the mass ratio of SnO 2 to NiO increases, the gas sensitivity value of SnO 2 /NiO/HrGO first increases and then decreases. When SnO 2 :NiO:HGO is 10:2:1, the response reaches the maximum. This change is the same as SnO 2 /NiO/rGO. The difference is that in all ratios, the response value of SnO 2 /NiO/HrGO is much higher than that of SnO 2 /NiO/rGO. Especially when the ratio is 10:2:1, the response value of SnO 2 /NiO/HrGO is 23.4%, which is 7.2% higher than SnO 2 /NiO/rGO.
  • Figure 11 shows the gas sensing response curve of the SnO 2 /NiO/rGO ternary composite sensor under different NO 2 concentrations. As the concentration of NO 2 increases, the coverage of NO 2 gas on the surface of the material increases, which intensifies the surface reaction and improves the gas-sensitive response. As shown in the figure, the gas-sensitive response values of SnO 2 /NiO/rGO to 200 ppb, 500 ppb, and 1 ppm NO 2 are 10.9%, 13.7%, and 16.2% respectively.
  • Embodiment 9 shows the gas-sensitive response histogram of the SnO 2 /NiO/HrGO ternary composite material (Example 4) gas sensor to different gases in different gas environments.
  • the response values of SnO 2 /NiO/HrGO to NO 2 , formaldehyde, ethanol, acetone, chloroform, and ethyl acetate are 23.4, 2.5%, 1.2%, 3.0%, 2.3%, and 1.7% respectively.
  • the ternary composite material has The response of NO2 is much greater than other gases.
  • the research focus of this invention is to prepare a ternary composite material SnO 2 /NiO/HrGO with reduced graphene oxide nanosieves supporting tin oxide and nickel oxide, and analyze its gas-sensing properties for NO 2 .
  • an oxidative etching method is used to improve graphene oxide, and a graphene oxide nanosieve is prepared.
  • high-temperature annealing reduction is used to obtain the SnO 2 /NiO/HrGO ternary composite material.
  • the sensitive material is dropped onto the interdigital electrode to obtain the SnO 2 /NiO/HrGO ternary composite material sensor, and gas sensing is performed on it. test.
  • SnO 2 /NiO/HrGO devices show extremely fast response speed, excellent environmental stability and good selectivity compared to SnO 2 /NiO/rGO in gas sensing tests of different composite ratio materials.
  • in the response value In terms of performance, SnO 2 /NiO/HrGO is higher.
  • the present invention successfully develops a simpler, more sensitive, and more reliable NO gas sensor based on SnO 2 /NiO/HrGO.

Abstract

Disclosed in the present invention are a SnO2/NiO/graphene ternary composite material, and a preparation method therefor and an application thereof. On the basis of graphene oxide (GO) prepared by means of the Hummers' method and a surface-controlled semiconductor sensitive material, and by means of methods such as solvothermal method, oxidation etching method, and high-temperature annealing method, a tin oxide/nickel oxide/reduced graphene oxide nanosieve (SnO2/NiO/HrGO) ternary composite material is obtained. The defects such as low gas-sensitive response and high working temperature still existing in a single graphene and a metal oxide gas sensor are successfully overcome by means of the ternary compounding and structural regulation of graphene and metal oxide, so that high-response test at room temperature of NO2 is achieved, and a good guiding effect on the design, preparation and NO2 gas-sensitive test of a multi-element composite material is achieved.

Description

一种SnO2/NiO/石墨烯三元复合材料及其制备方法与应用A SnO2/NiO/graphene ternary composite material and its preparation method and application 技术领域Technical field
本发明属于气敏材料技术，具体涉及一种SnO 2/NiO/石墨烯三元三维复合材料及其制备方法与应用。 The invention belongs to gas-sensitive material technology, and specifically relates to a SnO 2 /NiO/graphene ternary three-dimensional composite material and its preparation method and application.
背景技术Background technique
由于环境污染加剧以及生产生活需要，设计制备出灵敏度高、响应速度快、稳定性好、便携、成本低的气体传感器是一个重要课题。气敏材料决定着传感器质量，是传感器研究的关键。其中，石墨烯因其极高的电子迁移率、较大的比表面积而广受关注。然而，石墨烯敏感材料存在响应灵敏度偏低、响应慢及选择性差等瓶颈。通常，将石墨烯与金属氧化物复合形成异质结构，是解决该问题的有效途径之一。为了满足实际NO 2传感器的低检测限、低功耗、高灵敏度等要求，可以从设计不同的新型结构这一策略出发提高气体传感性能。作为常识，单一石墨烯或金属氧化物气体传感器存在气敏响应低、工作温度高等缺点，常通过石墨烯与金属氧化物复合来改善，现有复合气敏材料的气敏响应性能还需提升。 Due to the intensification of environmental pollution and the needs of production and life, it is an important topic to design and prepare gas sensors with high sensitivity, fast response, good stability, portability and low cost. Gas-sensitive materials determine the quality of sensors and are the key to sensor research. Among them, graphene has attracted widespread attention due to its extremely high electron mobility and large specific surface area. However, graphene-sensitive materials have bottlenecks such as low response sensitivity, slow response, and poor selectivity. Usually, combining graphene with metal oxides to form heterostructures is one of the effective ways to solve this problem. In order to meet the requirements of low detection limit, low power consumption, and high sensitivity of actual NO 2 sensors, gas sensing performance can be improved by designing different new structures. As common sense, single graphene or metal oxide gas sensors have shortcomings such as low gas-sensing response and high operating temperature, which are often improved by compounding graphene with metal oxides. The gas-sensing response performance of existing composite gas-sensing materials needs to be improved.
技术问题technical problem
本发明通过MnO 2在酸性条件下对GO的刻蚀制得氧化石墨烯纳米筛HGO，并获得了SnO 2/NiO/HrGO三元复合材料，该材料展现出优异的NO 2气敏特性。通过AFM测试，对比了GO与HGO的形貌结构，HGO除了具有多孔结构外，片径也比GO稍小。参照SnO 2/NiO/rGO，对SnO 2/NiO/HrGO采用了同样的的测试及表征方法。在室温条件下，SnO 2/NiO/HrGO三元复合材料对1 ppm的NO 2的响应为23.4%，明显比现有复合传感器件提高很多。 The present invention prepares graphene oxide nanosieve HGO by etching GO with MnO 2 under acidic conditions, and obtains SnO 2 /NiO/HrGO ternary composite material, which exhibits excellent NO 2 gas-sensing properties. Through AFM testing, the morphology and structure of GO and HGO were compared. In addition to having a porous structure, HGO has a slightly smaller sheet diameter than GO. Referring to SnO 2 /NiO/rGO, the same testing and characterization methods were adopted for SnO 2 /NiO/HrGO. At room temperature, the response of the SnO 2 /NiO/HrGO ternary composite material to 1 ppm NO 2 is 23.4%, which is significantly higher than the existing composite sensing device.
技术解决方案Technical solutions
本发明采用如下技术方案：一种SnO 2/NiO/石墨烯三元复合材料，包括纳米SnO 2、纳米NiO以及多孔石墨烯；具体的，将纳米SnO 2、纳米NiO、氧化石墨烯纳米筛混合后研磨、煅烧，得到SnO 2/NiO/石墨烯三元复合材料。 The present invention adopts the following technical solution: a SnO 2 /NiO/graphene ternary composite material, including nano SnO 2 , nano NiO and porous graphene; specifically, nano SnO 2 , nano NiO, and graphene oxide nano sieve are mixed After grinding and calcining, SnO 2 /NiO/graphene ternary composite material is obtained.
一种气体传感器件，包括叉指电极以及气敏材料，所述气敏材料为上述SnO 2/NiO/石墨烯三元复合材料；作为常识，还包括引线、底座等，本发明的创造性在于以上述SnO 2/NiO/石墨烯三元复合材料为气敏材料，其他用于器件的元件都为现有产品。 A gas sensor device includes interdigital electrodes and a gas-sensitive material. The gas-sensitive material is the above-mentioned SnO 2 /NiO / graphene ternary composite material. As common sense, it also includes leads, bases, etc. The creativity of the present invention lies in The above-mentioned SnO 2 /NiO/graphene ternary composite material is a gas-sensitive material, and other components used in the device are all existing products.
本发明中，将纳米NiO溶液、氧化石墨烯纳米筛溶液、纳米SnO 2溶液搅拌混合后离心处理，收集沉淀干燥、研磨，然后煅烧，得到SnO 2/NiO/石墨烯三元复合材料。优选的，将纳米NiO溶液、氧化石墨烯纳米筛溶液依次加入纳米SnO 2溶液中，搅拌混合后离心处理，收集沉淀干燥、研磨，然后煅烧，得到SnO 2/NiO/石墨烯三元复合材料。纳米SnO 2、纳米NiO、氧化石墨烯纳米筛的质量比为（1～20）∶（1～20）∶1，优选为（2～10）∶（2～5）∶1，再优选为（5～10）∶2∶1，比如10:2:1、5: 2:1。煅烧为空气中，180～220℃加热1.5～3小时。 In the present invention, the nano NiO solution, the graphene oxide nanosieve solution, and the nano SnO 2 solution are stirred and mixed and then centrifuged, and the precipitates are collected, dried, ground, and then calcined to obtain the SnO 2 /NiO/graphene ternary composite material. Preferably, the nano-NiO solution and the graphene oxide nanosieve solution are added to the nano-SnO 2 solution in sequence, stirred and mixed, and then centrifuged. The precipitate is collected, dried, ground, and then calcined to obtain the SnO 2 /NiO/graphene ternary composite material. The mass ratio of nano-SnO 2 , nano-NiO, and graphene oxide nanosieve is (1-20): (1-20):1, preferably (2-10): (2-5):1, and more preferably ( 5～10):2:1, such as 10:2:1, 5:2:1. Calcining is performed in air at 180-220°C for 1.5-3 hours.
本发明中，将高锰酸钾与氧化石墨烯溶液混合，然后微波加热，在经过盐酸处理，得到氧化石墨烯纳米筛；微波加热的功率为500～1000W，时间为3～6分钟，优选的微波加热的功率为600～800W，时间为4～5分钟；盐酸处理时，温度为60℃～80℃，时间为2h～4h。In the present invention, potassium permanganate and graphene oxide solution are mixed, then heated by microwave, and treated with hydrochloric acid to obtain graphene oxide nanosieve; the power of microwave heating is 500-1000W, and the time is 3-6 minutes, preferably The power of microwave heating is 600~800W and the time is 4~5 minutes; during hydrochloric acid treatment, the temperature is 60℃~80℃ and the time is 2h~4h.
本发明中，以镍盐、柠檬酸盐为原料，经过水热反应后干燥、煅烧，得到纳米NiO；优选的，水热反应为170℃～190℃反应15～18小时；煅烧为370℃～420℃下煅烧2h～4h。In the present invention, nickel salt and citrate are used as raw materials, dried and calcined after hydrothermal reaction to obtain nano NiO; preferably, the hydrothermal reaction is 170°C to 190°C for 15 to 18 hours; the calcination is 370°C to 190°C. Calculate at 420℃ for 2h~4h.
本发明中，以聚乙烯吡咯烷酮、锡盐为原料，经过溶剂热反应后干燥、煅烧，得到纳米SnO 2；优选的，溶剂热反应为170℃～190℃反应2～4小时；煅烧为470℃～520℃下煅烧1h～3h。 In the present invention, polyvinylpyrrolidone and tin salt are used as raw materials, and after solvothermal reaction, they are dried and calcined to obtain nano-SnO 2 ; preferably, the solvothermal reaction is at 170°C to 190°C for 2 to 4 hours; the calcination is at 470°C Calcined at ~520°C for 1h~3h.
本发明采用氧化刻蚀的方法制备得到氧化石墨烯纳米筛HGO，并建构一种二维还原氧化石墨烯纳米筛HrGO负载金属氧化物SnO 2纳米球与NiO纳米花的三元复合结构。基于此结构深入研究SnO 2/NiO/HrGO三元复合材料传感器对NO 2的传感性能，并与SnO 2/NiO/rGO三元复合材料的测试结果进行比较分析。SnO 2/NiO/HrGO三元复合材料器件的气敏响应显著提高。本发明公开了上述SnO 2/NiO/石墨烯三元复合材料或者气体传感器件在二氧化氮检测中的应用，或者上述SnO 2/NiO/石墨烯三元复合材料在制备二氧化氮检测气敏材料中的应用。 The present invention adopts an oxidative etching method to prepare graphene oxide nanosieve HGO, and constructs a two-dimensional reduced graphene oxide nanosieve HrGO supporting a ternary composite structure of metal oxide SnO 2 nanospheres and NiO nanoflowers. Based on this structure, the NO 2 sensing performance of the SnO 2 /NiO/HrGO ternary composite sensor was studied in depth, and the test results of the SnO 2 /NiO/rGO ternary composite material were compared and analyzed. The gas-sensing response of SnO 2 /NiO/HrGO ternary composite devices is significantly improved. The invention discloses the application of the above-mentioned SnO2 /NiO/graphene ternary composite material or gas sensor device in nitrogen dioxide detection, or the use of the above-mentioned SnO2 /NiO/graphene ternary composite material in the preparation of gas sensors for nitrogen dioxide detection. Applications in Materials.
有益效果beneficial effects
目前，关于石墨烯二元复合材料已有大量研究报道，而关于三元复合材料的报道偏少。构建石墨烯基三元复合异质结构，研究三元复合界面作用下的气敏特性，对于厘清石墨烯多元复合异质结构的气敏机制具有重要的意义。本发明以Hummers法制备氧化石墨烯（GO）和表面控制型半导体敏感材料为基础，采用溶剂热、氧化刻蚀、高温退火等方法获得了氧化锡/氧化镍/还原氧化石墨烯纳米筛（SnO 2/NiO/HrGO）三元复合材料，并研究了其对NO 2的室温气敏性能，具体研究成果如下：经结构调控得到一种以新型还原氧化石墨烯纳米筛（HrGO）为基底，负载氧化镍纳米花和氧化锡纳米球的三元复合材料，并对NO 2气体表现出更优异的气敏性能。采用氧化刻蚀法制备了氧化石墨烯纳米筛（HGO）。然后经高温退火还原得到SnO 2/NiO/HrGO三元复合材料。气敏测试结果表明，SnO 2/NiO/HrGO三元复合材料对1 ppm的最高响应值为23.4%，分别是SnO 2/HrGO二元复合材料、NiO/HrGO二元复合材料和单一HrGO的1.7、2和3.2倍。随着SnO 2与NiO质量比增加，SnO 2/NiO/HrGO的气敏响应先增大后降低。另外，HrGO系列产物的响应值比rGO系列高。 At present, there have been a large number of research reports on graphene binary composites, but there are fewer reports on ternary composites. Constructing a graphene-based ternary composite heterostructure and studying the gas-sensing characteristics under the action of the ternary composite interface is of great significance for clarifying the gas-sensing mechanism of graphene-based multi-component composite heterostructures. The present invention is based on the Hummers method for preparing graphene oxide (GO) and surface-controlled semiconductor sensitive materials, and adopts solvothermal, oxidative etching, high-temperature annealing and other methods to obtain tin oxide/nickel oxide/reduced graphene oxide nanosieve (SnO 2 /NiO/HrGO) ternary composite material, and its room temperature gas-sensing properties for NO 2 were studied. The specific research results are as follows: After structural control, a new reduced graphene oxide nanosieve (HrGO) was obtained as the substrate, loaded with The ternary composite material of nickel oxide nanoflowers and tin oxide nanospheres shows better gas sensing performance for NO 2 gas. Graphene oxide nanosieve (HGO) was prepared using oxidative etching method. Then, the SnO 2 /NiO/HrGO ternary composite material is obtained through high-temperature annealing and reduction. The gas sensing test results show that the highest response value of SnO 2 /NiO/HrGO ternary composite material to 1 ppm is 23.4%, which is 1.7 for SnO 2 /HrGO binary composite material, NiO/HrGO binary composite material and single HrGO respectively. , 2 and 3.2 times. As the mass ratio of SnO 2 to NiO increases, the gas sensing response of SnO 2 /NiO/HrGO first increases and then decreases. In addition, the response value of HrGO series products is higher than that of rGO series.
附图说明Description of the drawings
图1为NiO纳米花的SEM图。Figure 1 is the SEM image of NiO nanoflowers.
图2为SnO 2纳米球的SEM图。 Figure 2 is an SEM image of SnO2 nanospheres.
图3为HGO的AFM图像。Figure 3 shows the AFM image of HGO.
图4为HGO及三元复合材料SnO 2/NiO/HrGO的XRD图。 Figure 4 shows the XRD patterns of HGO and ternary composite SnO 2 /NiO/HrGO.
图5为HGO的XPS（a）全谱及（b）C 1s精细谱图。Figure 5 shows the XPS (a) full spectrum and (b) C 1s fine spectrum of HGO.
图6为三元复合材料SnO 2/NiO/HrGO的XPS精细谱图：（a）C 1s；（b）O 1s；（c）Ni 2p；（d）Sn 3d。 Figure 6 shows the XPS fine spectrum of the ternary composite SnO 2 /NiO/HrGO: (a) C 1s; (b) O 1s; (c) Ni 2p; (d) Sn 3d.
图7为SnO 2/NiO/HrGO、SnO 2/HrGO、NiO/HrGO及HrGO对1 ppm NO 2的气敏响应曲线。 Figure 7 shows the gas-sensitive response curves of SnO 2 /NiO/HrGO, SnO 2 /HrGO, NiO/HrGO and HrGO to 1 ppm NO 2 .
图8为SnO 2/NiO/HrGO三元复合材料传感器对不同浓度NO 2的气敏响应曲线。 Figure 8 shows the gas-sensitive response curve of SnO 2 /NiO/HrGO ternary composite sensor to different concentrations of NO 2 .
图9为不同质量比的（a）SnO 2/NiO/HrGO对1 ppm NO 2的实时气敏响应曲线。 Figure 9 shows the real-time gas sensing response curves of (a) SnO 2 /NiO/HrGO with different mass ratios to 1 ppm NO 2 .
图10为SnO 2/NiO/rGO与SnO 2/NiO/HrGO的气敏响应值折线图。 Figure 10 is a line chart of the gas sensing response values of SnO 2 /NiO/rGO and SnO 2 /NiO/HrGO.
图11为SnO 2/NiO/rGO三元复合材料传感器对不同浓度NO 2的气敏响应曲线。 Figure 11 shows the gas-sensitive response curve of SnO 2 /NiO/rGO ternary composite sensor to different concentrations of NO 2 .
图12为SnO 2/NiO/HrGO三元复合材料传感器对不同气体的气敏响应值柱状图。 Figure 12 is a histogram of the gas-sensitive response values of the SnO 2 /NiO/HrGO ternary composite sensor to different gases.
本发明的实施方式Embodiments of the invention
本发明采用二维石墨烯与球形、花形两种独特形貌的金属氧化物结合形成P-N-P异质结的三元复合结构模型，利用接触面的异质结构显著提高了该三元复合材料的NO 2气体传感性能。纳米球、纳米花、纳米片三种形貌的组合，使得SnO 2纳米球和NiO纳米花分散于石墨烯片层之间，有效降低石墨烯纳米片的堆叠，复合材料之间建立了电子输运通道，增加了气体吸附位点，丰富的氧缺陷可以提高复合材料对目标气体的敏感性。复合材料的维度降低或者尺寸结构减小会有特别的性质出现，比如表面和界面效应、小尺寸效应、量子尺寸效应、介电限域效应、宏观量子隧道效应。本发明制得SnO 2/NiO/石墨烯三元复合材料，并获得了优异的气敏响应特性。 The present invention uses two-dimensional graphene and metal oxides with two unique shapes, spherical and flower-shaped, to form a ternary composite structure model of PNP heterojunction. The heterostructure of the contact surface is used to significantly improve the NOx of the ternary composite material. 2 Gas sensing performance. The combination of the three morphologies of nanospheres, nanoflowers and nanosheets allows SnO2 nanospheres and NiO nanoflowers to be dispersed between graphene sheets, effectively reducing the stacking of graphene nanosheets and establishing electron transport between composite materials. Transport channels increase gas adsorption sites, and abundant oxygen defects can improve the sensitivity of composite materials to target gases. Special properties will appear when the dimensions or size structure of composite materials are reduced, such as surface and interface effects, small size effects, quantum size effects, dielectric confinement effects, and macroscopic quantum tunneling effects. The invention prepares SnO 2 /NiO/graphene ternary composite material and obtains excellent gas-sensitive response characteristics.
本发明采用退火还原的方式制备SnO 2/NiO/HrGO三元复合材料。首先，分别将SnO 2、NiO粉末加入乙醇中，获得均匀溶液。常规搅拌下，随后将乳白色SnO 2溶液逐滴滴加至绿色NiO溶液中，然后滴加HGO溶液，常规搅拌混合后离心收集产物，在60℃烘箱中干燥处理；再将固体研磨得到SnO 2/NiO/HGO粉末，再将其放入管式炉，空气中，200℃下煅烧2小时进行还原，最终得到SnO 2/NiO/HrGO三元复合材料。采用原子力显微镜对HrGO进行形貌扫描，并对复合材料SnO 2/NiO/HrGO进行XRD、Raman、XPS、FTIR等常规表征。 The present invention adopts annealing reduction method to prepare SnO 2 /NiO/HrGO ternary composite material. First, SnO 2 and NiO powders were added to ethanol respectively to obtain a uniform solution. Under normal stirring, the milky white SnO 2 solution was then added dropwise to the green NiO solution, and then the HGO solution was added dropwise. After mixing with normal stirring, the product was collected by centrifugation and dried in a 60°C oven; the solid was then ground to obtain SnO 2 / The NiO/HGO powder is then put into a tube furnace, calcined in air at 200°C for 2 hours for reduction, and finally the SnO 2 /NiO/HrGO ternary composite material is obtained. An atomic force microscope was used to scan the morphology of HrGO, and the composite SnO 2 /NiO/HrGO was conventionally characterized by XRD, Raman, XPS, and FTIR.
本发明所有原料都为市售产品，具体制备操作以及室温气敏测试都为现有技术，比如搅拌、洗涤等都为常规试验操作。本发明的氧化石墨烯参考常规Hummers方法制备得到，原理为用强酸强氧化剂对天然的石墨鳞片进行氧化插层，增大石墨片层的层间距，再利用热膨胀的方法进一步增加层间距，增加层间距的过程中结合机械搅拌和超声剥离的方法将石墨片层分开，最终成功制备出氧化石墨烯（GO），制备的过程如下：1）称取2 g天然石墨（500目），将其与50 ml的浓硫酸在250 ml的烧杯中混合，常规搅拌30 min；再加入1 g的硝酸钠，冰浴下常规搅拌2 h；再分三批加入7.3 g的高锰酸钾，然后将反应溶液在35 ℃水浴中搅拌反应2 h进一步完成氧化插层；再在混合溶液中加入150 ml的去离子水，搅拌30 min使溶液放热，利用热膨胀进一步加大层间距；然后在混合溶液中滴加55 ml的4%的双氧水溶液并搅拌30 min，使得进一步氧化和消耗掉多余的高锰酸钾，搅拌结束后得到棕黄色的GO悬浮液；2）将该棕黄色的悬浮溶液经过抽滤，并用稀盐酸（3%，100 ml）洗涤三次离心三次，然后用去离子水溶解放入透析袋中透析一个星期，透析结束后放入烘箱40℃烘干，最后得到氧化石墨烯（GO），分散在去离子水中。All the raw materials of the present invention are commercially available products, and the specific preparation operations and room temperature gas-sensitive tests are all existing technologies. For example, stirring, washing, etc. are all conventional test operations. The graphene oxide of the present invention is prepared by referring to the conventional Hummers method. The principle is to use strong acid and strong oxidant to oxidize and intercalate natural graphite flakes to increase the interlayer spacing of graphite flakes, and then use thermal expansion to further increase the interlayer spacing and increase the number of layers. During the spacing process, mechanical stirring and ultrasonic peeling were combined to separate the graphite sheets, and finally graphene oxide (GO) was successfully prepared. The preparation process is as follows: 1) Weigh 2 g of natural graphite (500 mesh), and combine it with Mix 50 ml of concentrated sulfuric acid in a 250 ml beaker and stir for 30 minutes. Add 1 g of sodium nitrate and stir for 2 hours under ice bath. Add 7.3 g of potassium permanganate in three batches, and then react. The solution was stirred in a 35°C water bath for 2 hours to further complete the oxidation intercalation; then 150 ml of deionized water, stir for 30 minutes to make the solution exothermic, and use thermal expansion to further increase the interlayer spacing; then add 55 ml of 4% hydrogen peroxide solution dropwise to the mixed solution and stir for 30 minutes to further oxidize and consume excess hydrogen peroxide. Potassium permanganate, after stirring, a brown-yellow GO suspension is obtained; 2) The brown-yellow suspension solution is filtered with suction, and diluted with dilute hydrochloric acid (3%, 100 ml), wash three times and centrifuge three times, then dissolve it with deionized water and put it into a dialysis bag for dialysis for one week. After dialysis, place it in an oven to dry at 40°C. Finally, graphene oxide (GO) is obtained, which is dispersed in deionized water.
实施例一 NiO纳米花的制备：采用溶剂热法来制备NiO纳米花，具体操作流程如下依次进行：（1）称取1.5 g的六水硝酸镍（Ni(NO 3) 2 . 6H 2O）于烧杯中，加入30 mL去离子水，得到溶液A；称取0.5 g二水柠檬酸钠（Na 3C 6H 5O 7 . 2H 2O），加入30 mL去离子水，得到溶液B；（2）将溶液B滴加至搅拌中的溶液A内，得到透明的浅绿色混合溶液，将其转移至聚四氟乙烯内衬高压釜中，在180℃反应16小时；待反应液冷却至室温，取出绿色沉淀，用去离子水、无水乙醇离心洗涤，离心速率为6000转/分钟；将洗涤过后的产物放置于60℃烘箱中烘干12小时得到前驱体粉末；（3）将前驱体粉末置于管式炉中，空气中，在400℃下煅烧3小时，得到NiO纳米花。图1为NiO纳米花的SEM图，粒径约3 μm，且花形完整、均匀、无杂质颗粒。 Example 1 Preparation of NiO nanoflowers: Use solvothermal method to prepare NiO nanoflowers. The specific operation process is as follows: (1) Weigh 1.5 g of nickel nitrate hexahydrate (Ni(NO 3 ) 2 . 6H 2 O) In the beaker, add 30 mL of deionized water to obtain solution A; weigh 0.5 g of sodium citrate dihydrate (Na 3 C 6 H 5 O 7 . 2H 2 O), and add 30 mL of deionized water to obtain solution B; (2) Add solution B dropwise to the stirring solution A to obtain a transparent light green mixed solution. Transfer it to a polytetrafluoroethylene-lined autoclave and react at 180°C for 16 hours; wait until the reaction solution is cooled to At room temperature, take out the green precipitate, and centrifuge it with deionized water and absolute ethanol at a centrifugal speed of 6000 rpm; place the washed product in a 60°C oven and dry it for 12 hours to obtain the precursor powder; (3) Combine the precursor powder with The bulk powder was placed in a tube furnace and calcined in air at 400°C for 3 hours to obtain NiO nanoflowers. Figure 1 shows the SEM image of NiO nanoflowers. The particle size is about 3 μm, and the flower shape is complete and uniform, with no impurity particles.
实施例二 SnO 2纳米球的制备：采用溶剂热法，并结合高温退火的方式得到粒径约500 nm的SnO 2纳米球。具体制备方法如下依次进行：（1）将0.5 g聚乙烯吡咯烷酮（PVP）、0.25 g五水四氯化锡（SnCl 4 . 5H 20）、60 mL甲醇加入聚四氟乙烯高压釜，置于180℃的烘箱中加热3小时；（2）反应完成后，将反应釜冷却至室温，取出底部的白色沉淀，以4000转/分钟离心处理，收集沉淀用乙醇重复离心洗涤3次，于烘箱中干燥得到前驱体；（3）将前驱体研磨成粉后放入管式炉，在空气氛围下500℃退火2小时得到SnO 2纳米球。图2为SnO 2纳米球的SEM图，SnO 2球的直径约为0.5 μm，SnO 2纳米球粒径均匀、形貌完整、无杂质颗粒。 Example 2: Preparation of SnO 2 nanospheres: SnO 2 nanospheres with a particle size of about 500 nm were obtained using a solvothermal method combined with high-temperature annealing. The specific preparation method is as follows: (1) Add 0.5 g polyvinylpyrrolidone (PVP), 0.25 g tin tetrachloride pentahydrate (SnCl 4 . 5H 2 0), and 60 mL methanol into a polytetrafluoroethylene autoclave, and place it in a polytetrafluoroethylene autoclave. Heating in an oven at 180°C for 3 hours; (2) After the reaction is completed, cool the reaction kettle to room temperature, take out the white precipitate at the bottom, centrifuge it at 4000 rpm, collect the precipitate, repeat centrifugation and washing with ethanol 3 times, and place it in the oven Dry to obtain the precursor; (3) Grind the precursor into powder and put it into a tube furnace, and anneal at 500°C for 2 hours in an air atmosphere to obtain SnO 2 nanospheres. Figure 2 is an SEM image of SnO 2 nanospheres. The diameter of SnO 2 nanospheres is about 0.5 μm. The SnO 2 nanospheres have uniform particle size, complete morphology, and no impurity particles.
实施例三 氧化石墨烯纳米筛（HGO）的制备：氧化石墨烯纳米筛的制备是基于酸性条件下MnO 2对GO的刻蚀，具体制备方法如下依次进行：（1）称量0.2 g KMnO 4加入到100 ml浓度为1 mg/ml的GO水溶液中，磁力搅拌20 min，得到深紫色溶液；（2）将上述深紫色溶液移入常规家用微波炉（700 W），高火加热5 min；（3）微波反应后的产物自然冷却至室温后取出，用去离子水离心洗涤5次；（4）洗净的沉淀物移入圆底烧瓶中，加入盐酸（37wt%）没过产物，然后放入水浴容器内70℃下水浴处理3 h，期间持续进行磁力搅拌；（5）盐酸处理后的产物离心处理，收集沉淀物进行洗涤，直至洗涤溶液呈中性，干燥便可得到HGO。图3为HGO的AFM图像，HGO片层上的孔不是规整的圆形结构且大小不同。 Example Preparation of graphene oxide nanosieve (HGO): The preparation of graphene oxide nanosieve is based on the etching of GO by MnO 2 under acidic conditions. The specific preparation method is as follows: (1) Weigh 0.2 g KMnO 4 Add to 100 ml of GO aqueous solution with a concentration of 1 mg/ml and stir magnetically for 20 minutes to obtain a dark purple solution; (2) Move the above dark purple solution into a conventional household microwave oven (700 W) and heat at high heat for 5 minutes; (3) ) After the microwave reaction, the product is naturally cooled to room temperature, then taken out, centrifuged and washed 5 times with deionized water; (4) The washed precipitate is moved into a round-bottomed flask, hydrochloric acid (37wt%) is added to cover the product, and then placed in a water bath Treat in a water bath at 70°C for 3 hours in the container, during which magnetic stirring is continued; (5) The product after hydrochloric acid treatment is centrifuged, and the precipitate is collected and washed until the washing solution is neutral, and HGO can be obtained by drying. Figure 3 shows the AFM image of HGO. The holes on the HGO sheet are not regular circular structures and have different sizes.
实施例四 SnO 2/NiO/HrGO三元复合材料的制备：传感器件的响应速度和灵敏度与活性材料的结构尺寸、比表面积、非均质性密切相关。采用退火还原的方式制备SnO 2/NiO/HrGO三元复合材料。首先，分别称取0.1g SnO 2纳米球、0.02g NiO纳米花于烧杯中并分别加入50 ml乙醇，得到乳白色SnO 2溶液、绿色NiO溶液；随后将乳白色SnO 2溶液逐滴滴加至NiO溶液中，然后取10 ml浓度为1 mg/ml的HGO水溶液滴加至上述混合溶液中，常规搅拌15分钟；然后以4000转/分钟离心处理，收集沉淀在60℃烘箱中干燥得到固体物，将固体物研磨得到SnO 2/NiO/HGO粉末，再将其放入管式炉，空气中，200℃下煅烧2小时进行还原，最终得到SnO 2/NiO/HrGO三元复合材料。 Example 4 Preparation of SnO 2 /NiO/HrGO ternary composite material: The response speed and sensitivity of the sensor device are closely related to the structural size, specific surface area, and heterogeneity of the active material. SnO 2 /NiO/HrGO ternary composite materials were prepared by annealing reduction. First, weigh 0.1g SnO 2 nanospheres and 0.02g NiO nanoflowers into a beaker and add 50 ml of ethanol respectively to obtain a milky white SnO 2 solution and a green NiO solution; then add the milky white SnO 2 solution dropwise to the NiO solution , then add 10 ml of HGO aqueous solution with a concentration of 1 mg/ml dropwise into the above mixed solution, and stir for 15 minutes as usual; then centrifuge at 4000 rpm, collect the precipitate, and dry it in a 60°C oven to obtain a solid. The solid matter is ground to obtain SnO 2 /NiO/HGO powder, which is then placed in a tube furnace, calcined in air at 200°C for 2 hours for reduction, and finally the SnO 2 /NiO/HrGO ternary composite material is obtained.
SnO 2/NiO/HrGO三元复合材料与HGO的XRD谱如图4所示。图中已标注出各个衍射平面，其中无任何杂质特征峰，也没有观察到与镍、锡或锡镍化合物相关的其他相，这表明SnO 2/NiO/HrGO三元复合材料成功合成。据报道，位于12.23°与42.59°的（001）、（004）衍射平面属于氧化石墨烯，位于20°的（002）峰属于还原氧化石墨烯；三元复合材料含有还原氧化石墨烯的（002）峰，这一重要变化说明复合材料成功还原。 The XRD spectrum of SnO 2 /NiO/HrGO ternary composite material and HGO is shown in Figure 4. Each diffraction plane has been marked in the figure, and there are no characteristic peaks of impurities, and no other phases related to nickel, tin or tin-nickel compounds were observed, which indicates that the SnO 2 /NiO/HrGO ternary composite material was successfully synthesized. According to reports, the (001) and (004) diffraction planes located at 12.23° and 42.59° belong to graphene oxide, and the (002) peak located at 20° belongs to reduced graphene oxide; the ternary composite material contains (002) of reduced graphene oxide. ) peak, this important change indicates that the composite material is successfully reduced.
图5给出了氧化石墨烯纳米筛的XPS全谱及C 1s精细谱图。在全谱中，可清晰观察到C、O对应的峰且未见其他杂质峰。C 1s精细谱中可以看出HGO中存在C=C、C-O、C=O等诸多官能团，其中含氧官能团占比很大。Figure 5 shows the XPS full spectrum and C 1s fine spectrum of graphene oxide nanosieve. In the full spectrum, the peaks corresponding to C and O can be clearly observed and no other impurity peaks are seen. It can be seen from the C 1s fine spectrum that there are many functional groups such as C=C, C-O, C=O, etc. in HGO, among which oxygen-containing functional groups account for a large proportion.
图6为窄扫描下SnO 2/NiO/HrGO三元复合材料的C 1s、O 1s、Ni 2p及Sn 3d精细谱。通过XPS表征分析了SnO 2/NiO/HrGO三元复合材料的表面化学元素组成和电子态。首先，对比HGO与SnO 2/NiO/HrGO的C 1s不难发现，SnO 2/NiO/HrGO中含氧官能团的含量与峰值均显著减少，这说明复合材料还原成功。其次，O 1s由三种不同化学状态的成分组成：O Lattice、O V、O- x。 Figure 6 shows the fine spectra of C 1s, O 1s, Ni 2p and Sn 3d of SnO 2 /NiO/HrGO ternary composite material under narrow scanning. The surface chemical element composition and electronic state of the SnO 2 /NiO/HrGO ternary composite material were analyzed through XPS characterization. First of all, comparing the C 1s of HGO and SnO 2 /NiO/HrGO, it is easy to find that the content and peak value of oxygen-containing functional groups in SnO 2 /NiO/HrGO are significantly reduced, which shows that the composite material is successfully reduced. Secondly, O 1s is composed of components in three different chemical states: O Lattice , O V , and O- x.
称取0.1g SnO 2纳米球加入50 ml乙醇，得到乳白色SnO 2溶液；然后取10 ml浓度为1 mg/ml的HGO水溶液滴加至上述乳白色SnO 2溶液中，常规搅拌15分钟；然后以4000转/分钟离心处理，收集沉淀在60℃烘箱中干燥得到固体物，将固体物研磨得到SnO 2/HGO粉末，再将其放入管式炉，空气中，200℃下煅烧2小时进行还原，最终得到SnO 2/HrGO复合材料。 Weigh 0.1g of SnO 2 nanospheres and add 50 ml of ethanol to obtain a milky white SnO 2 solution; then add 10 ml of an HGO aqueous solution with a concentration of 1 mg/ml dropwise into the above milky white SnO 2 solution, and stir for 15 minutes as usual; then stir at 4000 Centrifuge at 10 rpm/min, collect the precipitate and dry it in an oven at 60°C to obtain a solid. Grind the solid to obtain SnO 2 /HGO powder, which is then placed in a tube furnace and calcined in the air at 200°C for 2 hours for reduction. Finally, SnO 2 /HrGO composite material was obtained.
称取0.02g NiO纳米花于烧杯中加入50 ml乙醇，得到绿色NiO溶液；然后取10 ml浓度为1 mg/ml的HGO水溶液滴加至上述绿色NiO溶液中，常规搅拌15分钟；然后以4000转/分钟离心处理，收集沉淀在60℃烘箱中干燥得到固体物，将固体物研磨得到NiO/HGO粉末，再将其放入管式炉，空气中，200℃下煅烧2小时进行还原，最终得到NiO/HrGO复合材料。Weigh 0.02g of NiO nanoflowers and add 50 ml of ethanol into the beaker to obtain a green NiO solution; then add 10 ml of HGO aqueous solution with a concentration of 1 mg/ml dropwise into the above green NiO solution, and stir for 15 minutes as usual; then stir at 4000 Centrifuge at 100 rpm/min, collect the precipitate and dry it in a 60°C oven to obtain a solid. Grind the solid to obtain NiO/HGO powder, then put it into a tube furnace in the air and calcine at 200°C for 2 hours for reduction. Finally, NiO/HrGO composite material was obtained.
实施例五 气体传感器的制备：（1）制备叉指电极：在气敏测试中，叉指电极可作为物理载体元件，为附着且导通的气敏材料供给电压。本发明气体传感器的叉指电极是现有产品，基于硅工艺制造，采用传统微加工工艺制作而成，制备过程：将清洗干净后的硅片放入浓H 2SO 4与H 2O 2的混合溶液中，在90℃下处理半小时，得到表面亲水的硅片基底，洗涤干燥后在表面旋涂光刻胶，放上常规的叉指型掩膜版进行曝光显影，然后在基片上溅射金，最后超声剥离光刻胶制得叉指电极，制备的叉指电极的间距为10微米、宽10微米、长600微米。 Example 5 Preparation of gas sensors: (1) Preparation of interdigital electrodes: In gas sensing tests, interdigital electrodes can be used as physical carrier components to supply voltage to the attached and connected gas-sensitive materials. The interdigital electrode of the gas sensor of the present invention is an existing product. It is manufactured based on silicon technology and adopts traditional micro-machining technology. The preparation process is as follows: putting the cleaned silicon wafer into a mixture of concentrated H 2 SO 4 and H 2 O 2 In the mixed solution, treat it at 90°C for half an hour to obtain a silicon wafer substrate with a hydrophilic surface. After washing and drying, spin-coat photoresist on the surface, put a conventional interdigitated mask on for exposure and development, and then paint on the substrate. Gold was sputtered, and finally the photoresist was ultrasonically peeled off to prepare interdigital electrodes. The distance between the interdigitated electrodes prepared was 10 microns, 10 microns wide, and 600 microns long.
（2）滴涂气敏材料：首先，使用微量移液计取2 μL浓度为0.5 mg/mL的SnO 2/NiO/HrGO三元复合材料的乙醇溶液滴涂到叉指电极的有效接触区域，使得气敏材料连接叉指电极两极形成导电通道，待其自然干燥后放入60℃的烘箱干燥。再将叉指电极通过引线与铜底座相连即可得到气体传感器。 (2) Drop coating of gas-sensitive materials: First, use a micropipette to take 2 μL of an ethanol solution of SnO 2 /NiO/HrGO ternary composite material with a concentration of 0.5 mg/mL and drop it onto the effective contact area of the interdigital electrode, so that the gas The sensitive material connects the two electrodes of the interdigital electrode to form a conductive channel. After it is naturally dried, it is placed in an oven at 60°C for drying. Then connect the interdigital electrodes to the copper base through leads to obtain a gas sensor.
在上述器件的制备方法基础上，更改气敏材料作为对照：将SnO 2/NiO/HrGO三元复合材料更改为SnO 2/NiO/HGO粉末，其余不变，得到SnO 2/NiO/HGO气体传感器。 Based on the preparation method of the above device, the gas-sensitive material was changed as a control: the SnO 2 /NiO/HrGO ternary composite material was changed to SnO 2 /NiO/HGO powder, and the rest remained unchanged to obtain the SnO 2 /NiO/HGO gas sensor. .
将SnO 2/NiO/HrGO三元复合材料更改为NiO/HrGO复合材料，其余不变，得到NiO/HGO气体传感器。 Change the SnO 2 /NiO/HrGO ternary composite material into NiO/HrGO composite material, leaving the others unchanged, to obtain a NiO/HGO gas sensor.
将SnO 2/NiO/HrGO三元复合材料更改为SnO 2/HrGO复合材料，其余不变，得到SnO 2/HGO气体传感器。 The SnO 2 /NiO/HrGO ternary composite material is changed to SnO 2 /HrGO composite material, and the other components remain unchanged to obtain a SnO 2 /HGO gas sensor.
将2 μL浓度为1 mg/ml的HGO水溶液滴加至叉指电极的有效接触区域，待其自然干燥后放入管式炉，空气中200℃下煅烧2小时进行还原，最终得到HrGO气体传感器。2 μL of HGO aqueous solution with a concentration of 1 mg/ml was dropped into the effective contact area of the interdigital electrode. After it was naturally dried, it was placed in a tube furnace and calcined in the air at 200°C for 2 hours for reduction, and finally the HrGO gas sensor was obtained. .
实施例六 气敏传感测试：根据现有技术，利用Agilent B1500A半导体测试仪搭建了气敏测试***。该测试***包含供气与数据采集两部分；供气***以压缩空气作为背景气体，NO 2为目标气体，两气体先在混合腔充分混合，再通入器件所在的测试腔。 Embodiment 6 Gas-sensitive sensing test: According to the existing technology, a gas-sensitive testing system was built using the Agilent B1500A semiconductor tester. The test system consists of two parts: gas supply and data acquisition. The gas supply system uses compressed air as the background gas and NO 2 as the target gas. The two gases are first fully mixed in the mixing chamber and then passed into the test chamber where the device is located.
将气体传感器放入测试腔，两引脚与安捷伦测试仪连接。测试前，切换至测试仪的I-V模式，查看器件是否导通。然后，通入一段时间的背景气体以清除残余的NO 2气体，持续通入背景气体，将测试模式调为I/V-T，电压设定为0.5 V，这时可观察器件电阻的动态曲线。得到稳定的基线后通入目标气体NO 2，通过调节NO 2流速F n、背景气体流速F a确定所需要的NO 2浓度C n。待电阻稳定且持续合适的时间后可关闭所有气体，气敏曲线再次达到稳定时就得到了一个完整周期的气体响应。响应百分比为电阻变化与初始电阻的比例，计算如下： 。 Place the gas sensor into the test chamber and connect the two pins to the Agilent tester. Before testing, switch to the IV mode of the tester to check whether the device is conducting. Then, the background gas is introduced for a period of time to remove the residual NO 2 gas, and the background gas is continuously introduced. The test mode is adjusted to I/VT, and the voltage is set to 0.5 V. At this time, the dynamic curve of the device resistance can be observed. After obtaining a stable baseline, the target gas NO 2 is introduced, and the required NO 2 concentration C n is determined by adjusting the NO 2 flow rate F n and the background gas flow rate Fa . After the resistance is stable and lasts for a suitable period of time, all gases can be turned off. When the gas sensitivity curve reaches stability again, a complete cycle of gas response is obtained. The response percentage is the ratio of the resistance change to the initial resistance and is calculated as follows: .
改进后的石墨烯纳米筛多为小片结构且具有多孔结构。为了反映改进后的HGO与两氧化物复合后对NO 2传感特性的影响以及实现SnO 2/NiO/HrGO与SnO 2/NiO/HGO两种材料的灵敏度对比，本节测试了SnO 2/NiO/HrGO的NO 2气敏性能。 The improved graphene nanosieves are mostly small flake structures and have porous structures. In order to reflect the impact of the improved HGO compounded with two oxides on the NO 2 sensing characteristics and to achieve a sensitivity comparison between SnO 2 /NiO/HrGO and SnO 2 /NiO/HGO, SnO 2 /NiO was tested in this section /NO 2 gas sensing performance of HrGO.
图7给出了SnO 2/NiO/HrGO、SnO 2/HrGO、NiO/HrGO及HrGO对1 ppm NO 2的气敏响应曲线。图中SnO 2/NiO/HrGO、SnO 2/HrGO、NiO/HrGO及HrGO的气敏响应值分别为23.4%、13.9%、11.8%、7.4%。SnO 2/NiO/HrGO三元复合材料的气敏响应明显高于SnO 2/HrGO二元复合材料、NiO/HrGO二元复合材料及单一HrGO材料，有效展现出本发明响应速率快、响应状态平稳、恢复能力强的优势。另外，现有SnO 2-CuO/rGO传感器对5ppm的NO 2的响应仅为18%；单独金属氧化物的器件在室温下基本没有响应。 Figure 7 shows the gas-sensitive response curves of SnO 2 /NiO/HrGO, SnO 2 /HrGO, NiO/HrGO and HrGO to 1 ppm NO 2 . In the figure, the gas sensing response values of SnO 2 /NiO/HrGO, SnO 2 /HrGO, NiO/HrGO and HrGO are 23.4%, 13.9%, 11.8% and 7.4% respectively. The gas-sensing response of SnO 2 /NiO/HrGO ternary composite material is significantly higher than that of SnO 2 /HrGO binary composite material, NiO/HrGO binary composite material and single HrGO material, effectively demonstrating the fast response rate and stable response state of the present invention. , The advantage of strong recovery ability. In addition, the response of the existing SnO 2 -CuO/rGO sensor to 5 ppm NO 2 is only 18%; the device with a single metal oxide has basically no response at room temperature.
图8给出了SnO 2/NiO/HrGO三元复合材料传感器对200 ppb、500 ppb、1 ppm NO 2的气敏响应曲线，气敏响应值分别为16.9%、18.9%、23.4%。各浓度响应具有明显的变化，这说明SnO 2/NiO/HrGO对低浓度NO 2具有优秀的分辨能力，适合应用于对NO 2浓度检测限较低的场合。 Figure 8 shows the gas-sensitive response curves of the SnO 2 /NiO/HrGO ternary composite sensor to 200 ppb, 500 ppb, and 1 ppm NO 2. The gas-sensitive response values are 16.9%, 18.9%, and 23.4% respectively. There are obvious changes in the response of each concentration, which shows that SnO 2 /NiO/HrGO has excellent resolving power for low concentrations of NO 2 and is suitable for applications where the detection limit of NO 2 concentration is low.
实施例七：在实施例四的制备方法基础上上，改变SnO 2/NiO/HrGO的投料，即保持HGO水溶液的用量不变，改变SnO 2/NiO的用量，其余不变，得到不同原料比例的SnO 2/NiO/HrGO三元复合材料，进行实施例六的气体测试，图9探究了不同复合比例对SnO 2/NiO/HrGO三元复合材料传感器性能的影响。同样按照SnO 2:NiO:HGO的顺序取1:20:1、2:5:1、5:2:1、10:2:1、20:1:1共5个质量比（保持HGO水溶液的用量不变），实验中固定HGO的量，通过SnO 2与NiO两种氧化物的含量变化观察SnO 2/NiO/HrGO的响应值变化趋势，NO 2浓度均为1 ppm。 Example 7: Based on the preparation method of Example 4, change the input of SnO 2 /NiO/HrGO, that is, keep the amount of HGO aqueous solution unchanged, change the amount of SnO 2 /NiO, and keep the rest unchanged, to obtain different raw material ratios. The SnO 2 /NiO/HrGO ternary composite material was used for gas testing in Example 6. Figure 9 explores the impact of different compound ratios on the sensor performance of the SnO 2 /NiO/HrGO ternary composite material. Similarly, according to the order of SnO 2 :NiO:HGO, a total of 5 mass ratios of 1:20:1, 2:5:1, 5:2:1, 10:2:1, and 20:1:1 are selected (maintaining the HGO aqueous solution The amount remains unchanged), the amount of HGO was fixed in the experiment, and the response value change trend of SnO 2 /NiO/HrGO was observed through the changes in the content of SnO 2 and NiO oxides. The NO 2 concentration was all 1 ppm.
实施例八：首先，分别称取0.1g SnO 2纳米球、0.02g NiO纳米花于烧杯中并分别加入50 ml乙醇，得到乳白色SnO 2溶液、绿色NiO溶液；随后将乳白色SnO 2溶液逐滴滴加至NiO溶液中，然后取10 ml浓度为1 mg/ml的GO水溶液滴加至上述混合溶液中，常规搅拌15分钟；然后以4000转/分钟离心处理，收集沉淀在60℃烘箱中干燥得到固体物，将固体物研磨得到SnO 2/NiO/GO粉末，再将其放入管式炉，空气中200℃下煅烧2小时进行还原，最终得到SnO 2/NiO/rGO三元复合材料。再根据实施例五的方法制备得到SnO 2/NiO/rGO气体器件，按照实施例六的方法进行气体测试，图10为SnO 2/NiO/HrGO与SnO 2/NiO/rGO的气敏响应对比图，NO 2浓度均为1 ppm。可以观察到，随着SnO 2与NiO质量比增加，SnO 2/NiO/HrGO的气敏值先增大后降低，当SnO 2:NiO:HGO为10:2:1时，其响应达最大，该变化与SnO 2/NiO/rGO相同。不同的是，在所有比例中，SnO 2/NiO/HrGO的响应值比SnO 2/NiO/rGO的高很多。特别是在比例为10:2:1时，SnO 2/NiO/HrGO的响应值为23.4%，比SnO 2/NiO/rGO高7.2%。 Example 8: First, weigh 0.1g SnO 2 nanospheres and 0.02g NiO nanoflowers into a beaker and add 50 ml of ethanol respectively to obtain a milky white SnO 2 solution and a green NiO solution; then add the milky white SnO 2 solution drop by drop. Add to the NiO solution, then add 10 ml of GO aqueous solution with a concentration of 1 mg/ml dropwise into the above mixed solution, and stir for 15 minutes as usual; then centrifuge at 4000 rpm, collect the precipitate, and dry it in an oven at 60°C to obtain Solid matter, grind the solid matter to obtain SnO 2 /NiO/GO powder, then put it into a tube furnace and calcine it in air at 200°C for 2 hours for reduction, and finally obtain SnO 2 /NiO/rGO ternary composite material. Then the SnO 2 /NiO/rGO gas device was prepared according to the method of Example 5, and the gas test was performed according to the method of Example 6. Figure 10 is a comparison chart of the gas sensing responses of SnO 2 /NiO/HrGO and SnO 2 /NiO/rGO. , the NO 2 concentration is all 1 ppm. It can be observed that as the mass ratio of SnO 2 to NiO increases, the gas sensitivity value of SnO 2 /NiO/HrGO first increases and then decreases. When SnO 2 :NiO:HGO is 10:2:1, the response reaches the maximum. This change is the same as SnO 2 /NiO/rGO. The difference is that in all ratios, the response value of SnO 2 /NiO/HrGO is much higher than that of SnO 2 /NiO/rGO. Especially when the ratio is 10:2:1, the response value of SnO 2 /NiO/HrGO is 23.4%, which is 7.2% higher than SnO 2 /NiO/rGO.
图11为不同NO 2浓度下SnO 2/NiO/rGO三元复合材料传感器的气敏响应曲线。随着NO 2浓度增加，NO 2气体在材料表面覆盖范围增大，使得表面反应加剧，提高了气敏响应。如图所示，SnO 2/NiO/rGO对200 ppb、500 ppb、1 ppmNO 2的气敏响应值分别为10.9%、13.7%、16.2%。 Figure 11 shows the gas sensing response curve of the SnO 2 /NiO/rGO ternary composite sensor under different NO 2 concentrations. As the concentration of NO 2 increases, the coverage of NO 2 gas on the surface of the material increases, which intensifies the surface reaction and improves the gas-sensitive response. As shown in the figure, the gas-sensitive response values of SnO 2 /NiO/rGO to 200 ppb, 500 ppb, and 1 ppm NO 2 are 10.9%, 13.7%, and 16.2% respectively.
实施例九：图12给出了不同气体环境下SnO 2/NiO/HrGO三元复合材料（实施例四）气体传感器对不同气体的气敏响应柱状图。SnO 2/NiO/HrGO对NO 2、甲醛、乙醇、丙酮、三氯甲烷、乙酸乙酯的响应值分别为23.4、2.5%、1.2%、3.0%、2.3%和1.7%，三元复合材料对NO 2的响应远大于其他气体。 Embodiment 9: Figure 12 shows the gas-sensitive response histogram of the SnO 2 /NiO/HrGO ternary composite material (Example 4) gas sensor to different gases in different gas environments. The response values of SnO 2 /NiO/HrGO to NO 2 , formaldehyde, ethanol, acetone, chloroform, and ethyl acetate are 23.4, 2.5%, 1.2%, 3.0%, 2.3%, and 1.7% respectively. The ternary composite material has The response of NO2 is much greater than other gases.
总结：本发明的研究重点是制备一种还原氧化石墨烯纳米筛负载氧化锡与氧化镍的三元复合材料SnO 2/NiO/HrGO，并分析其对NO 2的气敏性能。首先采用氧化刻蚀法实现氧化石墨烯的改进，制备得到氧化石墨烯纳米筛。然后采用高温退火还原的方式得到SnO 2/NiO/HrGO三元复合材料，最后将该敏感材料滴加到叉指电极上获得SnO 2/NiO/HrGO三元复合材料传感器，并对其进行气敏测试。 Summary: The research focus of this invention is to prepare a ternary composite material SnO 2 /NiO/HrGO with reduced graphene oxide nanosieves supporting tin oxide and nickel oxide, and analyze its gas-sensing properties for NO 2 . First, an oxidative etching method is used to improve graphene oxide, and a graphene oxide nanosieve is prepared. Then high-temperature annealing reduction is used to obtain the SnO 2 /NiO/HrGO ternary composite material. Finally, the sensitive material is dropped onto the interdigital electrode to obtain the SnO 2 /NiO/HrGO ternary composite material sensor, and gas sensing is performed on it. test.
SnO 2/NiO/HrGO器件在不同复合比例材料的气敏测试中较SnO 2/NiO/rGO表现出极快的响应速度、极好的环境稳定性及良好的选择性，尤其是，在响应值方面，SnO 2/NiO/HrGO更高。总而言之，本发明成功地开发出一种更简单、灵敏、可靠的基于SnO 2/NiO/HrGO的NO 2气体传感器。 SnO 2 /NiO/HrGO devices show extremely fast response speed, excellent environmental stability and good selectivity compared to SnO 2 /NiO/rGO in gas sensing tests of different composite ratio materials. In particular, in the response value In terms of performance, SnO 2 /NiO/HrGO is higher. In summary, the present invention successfully develops a simpler, more sensitive, and more reliable NO gas sensor based on SnO 2 /NiO/HrGO.

Claims (10)

  1. 一种SnO 2/NiO/石墨烯三元复合材料，其特征在于，包括纳米SnO 2、纳米NiO以及多孔石墨烯。 A SnO 2 /NiO/graphene ternary composite material is characterized by including nano-SnO 2 , nano-NiO and porous graphene.
  2. 权利要求1所述SnO 2/NiO/石墨烯三元复合材料的制备方法，其特征在于，将纳米SnO 2、纳米NiO、氧化石墨烯纳米筛混合后研磨、煅烧，得到SnO 2/NiO/石墨烯三元复合材料。 The preparation method of SnO 2 /NiO/graphene ternary composite material according to claim 1, characterized in that, nano-SnO 2 , nano-NiO, and graphene oxide nanosieve are mixed and then ground and calcined to obtain SnO 2 /NiO/graphite. olefin ternary composite materials.
  3. 根据权利要求2所述SnO 2/NiO/石墨烯三元复合材料的制备方法，其特征在于，将纳米NiO溶液、氧化石墨烯纳米筛溶液、纳米SnO 2溶液搅拌混合后离心处理，收集沉淀干燥、研磨，然后煅烧，得到SnO 2/NiO/石墨烯三元复合材料。 The preparation method of SnO2 /NiO/graphene ternary composite material according to claim 2, characterized in that the nano-NiO solution, the graphene oxide nanosieve solution, and the nano- SnO2 solution are stirred and mixed and then centrifuged, and the precipitate is collected and dried. , grinding, and then calcining to obtain SnO 2 /NiO/graphene ternary composite material.
  4. 根据权利要求2所述SnO 2/NiO/石墨烯三元复合材料的制备方法，其特征在于，纳米SnO 2、纳米NiO、氧化石墨烯纳米筛的质量比为（1～20）∶（1～20）∶1。 The preparation method of SnO 2 /NiO/graphene ternary composite material according to claim 2, characterized in that the mass ratio of nano SnO 2 , nano NiO, and graphene oxide nano sieve is (1～20): (1～ 20):1.
  5. 根据权利要求2所述SnO 2/NiO/石墨烯三元复合材料的制备方法，其特征在于，将高锰酸钾与氧化石墨烯溶液混合，然后微波加热，再经过盐酸处理，得到氧化石墨烯纳米筛；以镍盐、柠檬酸盐为原料，经过水热反应后干燥、煅烧，得到纳米NiO；以聚乙烯吡咯烷酮、锡盐为原料，经过溶剂热反应后干燥、煅烧，得到纳米SnO 2。 The preparation method of SnO2 /NiO/graphene ternary composite material according to claim 2, characterized in that potassium permanganate and graphene oxide solution are mixed, then heated by microwave, and then treated with hydrochloric acid to obtain graphene oxide. Nanosieve; use nickel salt and citrate as raw materials, dry and calcine after hydrothermal reaction to obtain nano NiO; use polyvinylpyrrolidone and tin salt as raw materials, dry and calcine after solvothermal reaction to obtain nano SnO 2 .
  6. 根据权利要求5所述SnO 2/NiO/石墨烯三元复合材料的制备方法，其特征在于，制备氧化石墨烯纳米筛时，微波加热的功率为600～800W，时间为4～5分钟，盐酸处理时，温度为60℃～80℃，时间为2h～4h；制备纳米NiO时，溶剂热反应为170℃～190℃反应2～4小时，煅烧为470℃～520℃下煅烧1h～3h；制备时纳米SnO 2，水热反应为170℃～190℃反应15～18小时；煅烧为370℃～420℃下煅烧2h～4h。 The preparation method of SnO2 /NiO/graphene ternary composite material according to claim 5, characterized in that when preparing graphene oxide nanosieve, the power of microwave heating is 600~800W, the time is 4~5 minutes, and the hydrochloric acid During treatment, the temperature is 60°C to 80°C and the time is 2h to 4h; when preparing nano NiO, the solvothermal reaction is 170°C to 190°C for 2 to 4 hours, and the calcination is calcination at 470°C to 520°C for 1h to 3h; During the preparation of nano-SnO 2 , the hydrothermal reaction is at 170°C to 190°C for 15 to 18 hours; the calcination is at 370°C to 420°C for 2h to 4h.
  7. 一种气体传感器件，包括叉指电极以及气敏材料，其特征在于，所述气敏材料为权利要求1所述SnO 2/NiO/石墨烯三元复合材料。 A gas sensor device includes an interdigital electrode and a gas-sensitive material, characterized in that the gas-sensitive material is the SnO 2 /NiO/graphene ternary composite material described in claim 1.
  8. 一种氮氧化物气体检测方法，将权利要求7所述气体传感器置入含有氮氧化物气体的环境中，完成氮氧化物气体检测。A method for detecting nitrogen oxide gas. The gas sensor described in claim 7 is placed in an environment containing nitrogen oxide gas to complete the detection of nitrogen oxide gas.
  9. 权利要求1所述SnO 2/NiO/石墨烯三元复合材料在二氧化氮检测中的应用或者在制备二氧化氮检测气敏材料中的应用。 The application of the SnO 2 /NiO/graphene ternary composite material described in claim 1 in nitrogen dioxide detection or in the preparation of gas-sensitive materials for nitrogen dioxide detection.
  10. 权利要求7所述气体传感器件在二氧化氮检测中的应用。Application of the gas sensor device described in claim 7 in nitrogen dioxide detection.
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