WO2018082585A1 - Synthesis method for composite gas sensitive material of porous zinc oxide nanosheet loaded with a high-dispersion nano precious metal - Google Patents

Synthesis method for composite gas sensitive material of porous zinc oxide nanosheet loaded with a high-dispersion nano precious metal Download PDF

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WO2018082585A1
WO2018082585A1 PCT/CN2017/109017 CN2017109017W WO2018082585A1 WO 2018082585 A1 WO2018082585 A1 WO 2018082585A1 CN 2017109017 W CN2017109017 W CN 2017109017W WO 2018082585 A1 WO2018082585 A1 WO 2018082585A1
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zinc oxide
composite gas
gas sensing
oxide nanosheet
precious metal
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PCT/CN2017/109017
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French (fr)
Chinese (zh)
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占金华
封振宇
韩雪
马妍星
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山东大学
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/20—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds
    • B22F9/22—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds using gaseous reductors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • B22F1/054—Nanosized particles
    • B22F1/0545—Dispersions or suspensions of nanosized particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G9/00—Compounds of zinc
    • C01G9/02—Oxides; Hydroxides
    • C01G9/03—Processes of production using dry methods, e.g. vapour phase processes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • 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
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer

Definitions

  • the invention relates to a method for synthesizing a porous zinc oxide nanosheet loaded high-dispersion nano precious metal composite gas sensing material, and belongs to the field of preparation of inorganic nano materials.
  • VOCs volatile organic compounds
  • VOCs volatile organic compounds
  • these methods have some disadvantages: analysis and detection The hysteresis is not conducive to on-line detection; sample pretreatment and detection procedures are more complicated. Gas sensing can just make up for the weakness of the above detection methods, so the research on the synthesis method of gas sensing materials is particularly important.
  • the conductive gas sensor detects the change in the concentration of the gas to be measured by detecting the change in the conductivity (resistance) before and after the reaction of the sensor element with the substance to be tested.
  • a common n-type semiconductor gas sensing material zinc oxide has obvious gas-sensitive response in the detection of some VOCs and polychlorinated biphenyls, such as ethanol, acetone, chlorobenzene and the like.
  • Various morphological nano-zinc oxide materials for example, nanorods, nanosheets, multi-structured nanoflowers, nano-hollow structures, and the like, have been prepared by liquid phase synthesis.
  • the inherent selectivity of the zinc oxide material itself also causes it to be unresponsive to a portion of the VOCs, for example, the gas-sensitive response to benzene, toluene, xylene, and the like is scarce.
  • Precious metals gold, platinum, palladium, silver
  • their incorporation can effectively improve the deficiency of zinc oxide materials, increase the types of gases that can be simultaneously detected, and further increase the zinc oxide to various VOCs. Gas sensing performance.
  • Nano-gold, platinum, and palladium perform well in the field of catalytic oxidation of VOCs, and the catalytic performance of small particles of 2-10 nm tends to be good.
  • Small-sized monodisperse nano-gold, platinum, palladium, and silver are usually carried out by means of small organic molecules having a functional group such as a mercapto group, an amino group or a carboxyl group, or a macromolecular surfactant such as polyvinylpyrrolidone or tritonone as a protective agent. synthesis. Although this method can regulate the morphology and size of nano precious metals, it also covers the active sites of noble metal nanoparticles, thus affecting the surface adsorption and electron conduction of nano precious metals. At the same time, the distribution and content of precious metal nanoparticles also affect the gas sensing properties of the composite.
  • the photocatalytic properties of zinc oxide are used to deposit precious metals on the surface of single crystal porous zinc oxide.
  • the size and distribution of noble metals can be controlled by controlling the concentration of the system and the reaction time.
  • zinc oxide will partially dissolve itself in the light of water, and the morphology will change, and the stability is not good, which makes the process difficult to enlarge.
  • Chinese patent document CN 103908964 A discloses a noble metal doped zinc oxide nano powder and its preparation and application, The preparation steps are as follows: (1) heating the organic alcohol solvent to 150-190 ° C; (2) adding an aqueous solution of a zinc acetate-precious metal salt mixture, reacting at 150-190 ° C for 5 - 60 min, after the reaction is completed, centrifuging, The obtained solid sample is washed; (3) the sample obtained in the step (2) is dried, and the obtained noble metal-doped zinc oxide nano powder has a particle diameter of 30 to 50 nm.
  • the method for preparing precious metal doped zinc oxide nanopowder is easy to obtain, simple to operate, and suitable for photocatalytic treatment of organic sewage; however, the product prepared by the invention has low specific surface area, requires use of an organic solvent, and has a high treatment temperature.
  • Chinese patent document CN 102649060A discloses a porous zinc oxide-silver composite nanorod and a preparation method and use thereof.
  • the zinc acetate ethanol solution and the oxalic acid dihydrate solution are mixed and placed in a sealed state, and the temperature is maintained at 70 to 90 ° C for at least 5 hours, and then centrifuged, washed and dried, and then the obtained oxalic acid is firstly obtained.
  • the zinc is annealed at 430-470 ° C for at least 2 h, and then added to a silver nitrate glycol solution, stirred under visible light for at least 15 min, and then subjected to centrifugation, washing and drying to obtain a target product.
  • the composite nanorods prepared by the invention are composed of zinc oxide particles, and the surface of the porous rod-shaped zinc oxide is loaded with silver particles, which is a deposition between particles, a relatively low specific surface area, and the active sites of the nanoparticles are covered, and is applicable. Visible light photocatalytic degradation in water contaminated with organic matter.
  • the present invention provides a method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material which is simple, green, reproducible and capable of mass production.
  • a method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
  • the method for preparing basic zinc carbonate in the step (1) comprises the steps of: dissolving zinc acetate and urea in water, reacting at 110-140 ° C for 2-6 h; centrifuging, washing, and drying.
  • Basic zinc carbonate
  • reaction temperature is 120 ° C and the reaction time is 2 h.
  • the molar ratio of zinc acetate to urea is 1:1-5; preferably, the molar ratio of zinc acetate to urea is 1:2.
  • the drying conditions are dried at 60 ° C for 12 h.
  • the aqueous solution of the noble metal ion in the step (1) is an aqueous solution of chloroauric acid, chloroplatinic acid, palladium chloride or silver nitrate.
  • the mass concentration of the noble metal in the aqueous solution of the precious metal ion in the step (1) is 0.1 wt% to 10 wt%; preferably, the mass concentration of the noble metal in the aqueous solution of the noble metal ion in the step (1) is 1 wt. %-5wt%.
  • the mass ratio of the basic zinc carbonate to the noble metal in the step (1) is 1:0.05-5.
  • the soaking condition in the step (1) is soaked for 12-24 hours at room temperature.
  • the drying condition in the step (2) is dried at 60 ° C for 12 h.
  • the calcination condition in the step (2) is 350-500 ° C, and calcination is 1-4 h.
  • the calcination conditions are calcined at 400 ° C for 2 h.
  • the precipitate in the reaction liquid in the step (2) is subjected to centrifugal washing, drying, calcination, and further reacted under a hydrogen atmosphere at 150-180 ° C for 1-4 h; preferably, under a hydrogen atmosphere.
  • the reaction was carried out at 160 ° C for 2 h.
  • the precipitate in the reaction liquid in the step (2) is subjected to centrifugal washing, drying, calcination, and further reduction under a hydrogen atmosphere.
  • the invention utilizes a room temperature liquid phase ion exchange reaction, and the noble metal ions can be uniformly and controlly attached to the surface of the basic zinc carbonate, and the calcination, the basic zinc carbonate is decomposed to generate a gas such as carbon dioxide to form a porous structure of zinc oxide;
  • the noble metal of the zinc oxide nanosheet can be reduced into nanoparticles (the elemental nano gold, platinum, palladium can be stably existed; the elemental nano silver is easily partially oxidized, and can be reduced by hydrogen atmosphere).
  • the noble metal ions are evenly distributed on the surface of the basic zinc carbonate precipitation, so the noble metal nanoparticles are highly dispersed after calcination, the particle size distribution is narrow, and evenly distributed on the surface of the porous zinc oxide nanosheet; by regulating the precious metal ions in the soaking solution
  • the concentration and the time of soaking can control the particle size and loading of the nano precious metal in the prepared material; the surface of the noble metal nanoparticle is covered with no protective agent, the active site is fully exposed, and the particle size is less than 10 nm, which can exist stably for a long time. Excellent sensitivity.
  • the porous zinc oxide nanosheet has uniform pore distribution, large specific surface area, and surface exposed non-polar crystal plane, which is favorable for noble metal nanoparticles. Disperse stable load.
  • the composite gas sensing material prepared by the method has better sensitivity to gas sensing of VOCs and chlorobenzene gases than pure nano zinc oxide materials, and achieves a highly sensitive response to various gases.
  • the preparation method is green, simple and reproducible, and is a process that can be manufactured and applied on a scale.
  • Example 1 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 1.
  • Example 2 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 2.
  • Example 3 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 3.
  • Example 4 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 4.
  • Example 5 is a transmission electron microscope photograph of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 5. sheet.
  • Example 6 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 6.
  • Example 7 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 1.
  • Example 8 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 2.
  • Example 9 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 3.
  • Example 10 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 4.
  • Example 11 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 5.
  • Example 12 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 6.
  • a method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
  • the nano gold has a particle size of about 2 nm and a loading of about 0.5 wt%.
  • FIG. 1 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano gold particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
  • FIG. 7 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nano-gold composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide (corresponding to the standard card JCPDS No. 36- In addition to 1451), a relatively weak nanogold diffraction peak appears (corresponding to the standard card JCPDS No. 04-0784, which is known as the gold (111) and (200) crystal faces), and there are no other peaks, so the composite material is A composite of zinc oxide and gold, with no other material structure.
  • Example 2 As described in Example 1, the difference was that an aqueous solution of chloroauric acid having a mass concentration of 3 wt% was used in the step (2).
  • the nano gold has a particle size of about 5 nm and a loading of about 2 wt%.
  • FIG. 2 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano gold particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
  • FIG. 8 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide is replaced (corresponding to the standard card JCPDS No. 36- In addition to 1451), a nanogold diffraction peak appeared (corresponding to the standard card JCPDS No. 04-0784, which is known as the (111), (200) and (220) crystal faces of gold), and there are no other peaks, so the composite material As a composite of zinc oxide and gold, there is no other material structure.
  • Example 2 As described in Example 1, the difference was that an aqueous solution of chloroauric acid having a mass concentration of 5 wt% was used in the step (2).
  • the nano gold has a particle size of about 10 nm and a loading of about 5 wt%.
  • FIG. 3 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano gold particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
  • FIG. 9 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nano-gold composite gas sensing material prepared in the present embodiment, and the diffraction peak of the wurtzite zinc oxide is not shown in the figure (corresponding to the standard card JCPDS No. 36- In addition to 1451), there is a nano-gold diffraction peak with a certain intensity (corresponding to the standard card JCPDS No. 04-0784, which can be known as the (111), (200) and (220) crystal faces of gold), and there are no other peaks. Therefore, the composite material is a composite material of zinc oxide and gold, and has no other material structure.
  • a method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
  • the nanopalladium has a particle size of about 2 nm and a loading of about 0.5 wt%.
  • FIG. 4 is a transmission electron micrograph of the porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano-palladium particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
  • FIG. 10 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment, and the diffraction peak of the wurtzite zinc oxide is not shown in the figure (corresponding to the standard card JCPDS No. 36- In addition to 1451), a relatively weak nanopalladium diffraction peak appeared (corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of palladium), and there are no other peaks, so the composite material is A composite of zinc oxide and palladium with no other material structure.
  • Example 4 As described in Example 4, the difference was that a palladium chloride aqueous solution having a mass concentration of 3 wt% was used in the step (2).
  • the nano-palladium has a particle size of about 5 nm and a loading of about 2 wt%.
  • FIG. 5 is a transmission electron micrograph of the porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano-palladium particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
  • FIG. 11 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide (corresponding to the standard card JCPDS No. 36- In addition to 1451), a nanopalladium diffraction peak appeared (corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of palladium), and there are no other peaks, so the composite material is zinc oxide and Palladium composite material, no other material structure.
  • the diffraction peak of wurtzite zinc oxide corresponding to the standard card JCPDS No. 36- In addition to 1451
  • a nanopalladium diffraction peak appeared (corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of palladium), and there are no other peaks, so
  • Example 4 As described in Example 4, the difference was that a palladium chloride aqueous solution having a mass concentration of 5 wt% was used in the step (2).
  • the nano-palladium has a particle size of about 8 nm and a loading of about 5 wt%.
  • FIG. 6 is a transmission electron micrograph of the porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano-palladium particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
  • FIG. 12 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide (corresponding to the standard card JCPDS No. 36- In addition to 1451), there is a nanopalladium diffraction peak with a certain intensity (corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of palladium), and there are no other peaks, so the composite material As a composite of zinc oxide and palladium, there is no other material structure.
  • the diffraction peak of wurtzite zinc oxide corresponding to the standard card JCPDS No. 36- In addition to 1451
  • the nanopalladium diffraction peak with a certain intensity corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of
  • a method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
  • the precipitate in the reaction liquid obtained in the step (2) is washed by centrifugation, dried in an oven at 60 ° C for 12 h, and then calcined at 400 ° C for 2 h in a muffle furnace; then, the product is placed in a porcelain boat, in a tube type.
  • the composite gas-sensitive material was obtained by reduction in a furnace at 160 ° C for 2 h under a hydrogen atmosphere.
  • the nano silver has a particle size of about 2 nm and a loading of about 0.5 wt%.
  • Example 2 As described in Example 1, the difference was that an aqueous solution of chloroplatinic acid having a mass concentration of 1% by weight was used in the step (2).
  • Example 2 As described in Example 1, the difference was that an aqueous solution of chloroplatinic acid having a mass concentration of 3 wt% was used in the step (2).
  • Example 2 As described in Example 1, the difference was that an aqueous solution of chloroplatinic acid having a mass concentration of 5 wt% was used in the step (2).
  • Example 7 As described in Example 7, the difference was that a silver nitrate aqueous solution having a mass concentration of 3 wt% was used in the step (2).
  • Example 7 As described in Example 7, the difference was that a silver nitrate aqueous solution having a mass concentration of 5 wt% was used in the step (2).
  • a method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
  • a porous zinc oxide nanosheet the preparation steps are as follows:
  • the basic zinc carbonate obtained in the step (1) is calcined in a muffle furnace at 400 ° C for 2 hours to obtain a porous zinc oxide nanosheet.
  • a method for synthesizing porous zinc oxide nanosheet-loaded nanometer cobalt oxide composite gas sensing material comprises the following steps:
  • the instrument used for testing is the WS-30A gas sensitivity tester produced by Zhengzhou Yusheng Electronic Technology Co., Ltd., and the gas sensor is a side-heating sintered component made according to the traditional method.
  • the sensitivity of the gas sensor is reflected by recording the voltage across the load resistor in series with the gas sensor.
  • the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-precious metal composite gas sensing material (for example, Examples 1-14) has a significantly better gas sensing detection response value for VOCs and chlorobenzene gases than pure nano zinc oxide.
  • zinc oxide-loaded nano-cobalt oxide materials (for example, Comparative Examples 1, 2), and achieve a highly sensitive response to a variety of gases, response and recovery time is also faster. Therefore, the method of the present invention has potential development and application value.

Abstract

Disclosed is a synthesis method for a composite gas sensitive material of a porous zinc oxide nanosheet loaded with a high-dispersion nano precious metal. The method comprises the following steps: (1) basic zinc carbonate is immersed into a water solution of precious metal ions, stirring is conducted in the absence of light, and a reaction solution containing precipitate is obtained; and (2) the precipitate in the reaction solution obtained in step (1) is subjected to centrifugal washing, drying and calcination, and the composite gas sensitive material is obtained. The material can be used for gas sensitive sensing detection of volatile organic pollutants (VOCs and chlorobenzene gases), the gas sensitive response is good, the synthesis method for the material is green and simple and convenient, with good repeatability, and mass production and application to gas sensing detection can be easily achieved.

Description

一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法Method for synthesizing porous zinc oxide nanosheet loaded high dispersion nano precious metal composite gas sensing material 技术领域Technical field
本发明涉及一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，属于无机纳米材料制备领域。The invention relates to a method for synthesizing a porous zinc oxide nanosheet loaded high-dispersion nano precious metal composite gas sensing material, and belongs to the field of preparation of inorganic nano materials.
背景技术Background technique
室内空气品质研究者称其在室内所采样分析的所有挥发性有机物为VOCs，易挥发性有机物(VOCs)是三类室内空气污染物中影响较为严重的一种。随着人们在室内时间的持续增长，室内环境与人们的关系就显得更加密切更加重要。检测VOCs的方法有很多，如气相色谱法、红外法、SPR光电二极管检测法、重量化学传感器法、催化燃烧式传感器法、光离子化检测器法等，然而，这些方法存在一些缺点：分析检测的滞后性不利于在线检测；样品的预处理及检测程序比较复杂。气敏检测恰恰可以弥补以上检测方法的弱点，所以气敏材料的合成方法的研究显得尤为重要。Indoor air quality researchers say that all volatile organic compounds sampled and analyzed indoors are VOCs, and volatile organic compounds (VOCs) are one of the three types of indoor air pollutants. As people's indoor time continues to grow, the relationship between indoor environment and people becomes more important and more important. There are many methods for detecting VOCs, such as gas chromatography, infrared, SPR photodiode detection, weight chemical sensor method, catalytic combustion sensor method, photoionization detector method, etc. However, these methods have some disadvantages: analysis and detection The hysteresis is not conducive to on-line detection; sample pretreatment and detection procedures are more complicated. Gas sensing can just make up for the weakness of the above detection methods, so the research on the synthesis method of gas sensing materials is particularly important.
导电型气体传感器(气敏传感器)是通过检测传感器敏感元件与待测物质发生反应前后的电导率(电阻)的变化来检测待测气体的浓度变化。氧化锌作为一种常见的n-型半导体气敏材料，在一些VOCs气体以及多氯联苯类污染物的检测中都有明显的气敏响应，例如，乙醇、丙酮、氯苯等。各种形貌的纳米氧化锌材料，例如，纳米棒、纳米片、多级结构的纳米花、纳米空心结构等等，都已经通过液相合成的方法制备获得。然而，氧化锌材料本身固有的选择性也造成了它对一部分VOCs是无响应的，例如，对苯、甲苯、二甲苯等的气敏响应几乎没有。贵金属(金、铂、钯、银)具备优异的有机气体异相催化活性，它的掺入可以有效的改善氧化锌材料的不足，增加可同时检测的气体种类并进一步提高氧化锌对多种VOCs的气敏性能。The conductive gas sensor (gas sensor) detects the change in the concentration of the gas to be measured by detecting the change in the conductivity (resistance) before and after the reaction of the sensor element with the substance to be tested. As a common n-type semiconductor gas sensing material, zinc oxide has obvious gas-sensitive response in the detection of some VOCs and polychlorinated biphenyls, such as ethanol, acetone, chlorobenzene and the like. Various morphological nano-zinc oxide materials, for example, nanorods, nanosheets, multi-structured nanoflowers, nano-hollow structures, and the like, have been prepared by liquid phase synthesis. However, the inherent selectivity of the zinc oxide material itself also causes it to be unresponsive to a portion of the VOCs, for example, the gas-sensitive response to benzene, toluene, xylene, and the like is scarce. Precious metals (gold, platinum, palladium, silver) have excellent heterogeneous catalytic activity of organic gases, and their incorporation can effectively improve the deficiency of zinc oxide materials, increase the types of gases that can be simultaneously detected, and further increase the zinc oxide to various VOCs. Gas sensing performance.
纳米金、铂、钯在针对VOCs气体的催化氧化领域性能优异，2-10nm小颗粒的催化性能往往较好。小尺寸单分散的纳米金、铂、钯、银通常都借助带有巯基、氨基、羧基功能基团的有机小分子或者聚乙烯吡咯烷酮、曲拉通等大分子表面活性剂作为保护剂进行液相合成。这种方法虽然可以调控纳米贵金属形貌和尺寸，但也覆盖了贵金属纳米颗粒活性位点，从而影响纳米贵金属的表面吸附和电子传导。同时，贵金属纳米颗粒的分布和含量也会影响复合材料的气敏性能。Nano-gold, platinum, and palladium perform well in the field of catalytic oxidation of VOCs, and the catalytic performance of small particles of 2-10 nm tends to be good. Small-sized monodisperse nano-gold, platinum, palladium, and silver are usually carried out by means of small organic molecules having a functional group such as a mercapto group, an amino group or a carboxyl group, or a macromolecular surfactant such as polyvinylpyrrolidone or tritonone as a protective agent. synthesis. Although this method can regulate the morphology and size of nano precious metals, it also covers the active sites of noble metal nanoparticles, thus affecting the surface adsorption and electron conduction of nano precious metals. At the same time, the distribution and content of precious metal nanoparticles also affect the gas sensing properties of the composite.
有文献利用氧化锌的光催化性质，在单晶多孔氧化锌表面液相光催化沉积贵金属，通过控制体系浓度、反应时间等条件可以控制贵金属的尺寸和分布。但是氧化锌在水中光照下自身也会有部分发生溶解，且形貌会变化，稳定性不好，致使这种工艺不便于放大应用。In the literature, the photocatalytic properties of zinc oxide are used to deposit precious metals on the surface of single crystal porous zinc oxide. The size and distribution of noble metals can be controlled by controlling the concentration of the system and the reaction time. However, zinc oxide will partially dissolve itself in the light of water, and the morphology will change, and the stability is not good, which makes the process difficult to enlarge.
中国专利文献CN 103908964 A公开了一种贵金属掺杂氧化锌纳米粉体及其制备、应用， 制备步骤如下：(1)将有机醇溶剂加热至150—190℃；(2)加入乙酸锌-贵金属盐混合物的水溶液，在150—190℃反应5—60 min，反应结束后，离心分离，将所得固体样品洗涤；(3)将步骤(2)所得样品干燥，即得，所得贵金属掺杂氧化锌纳米粉体粒径为30-50nm。该发明制备贵金属掺杂氧化锌纳米粉的方法原料易得，操作简单，适用于光催化处理有机污水领域；但该发明制备的产品比表面积低，需要使用有机溶剂，处理温度较高。Chinese patent document CN 103908964 A discloses a noble metal doped zinc oxide nano powder and its preparation and application, The preparation steps are as follows: (1) heating the organic alcohol solvent to 150-190 ° C; (2) adding an aqueous solution of a zinc acetate-precious metal salt mixture, reacting at 150-190 ° C for 5 - 60 min, after the reaction is completed, centrifuging, The obtained solid sample is washed; (3) the sample obtained in the step (2) is dried, and the obtained noble metal-doped zinc oxide nano powder has a particle diameter of 30 to 50 nm. The method for preparing precious metal doped zinc oxide nanopowder is easy to obtain, simple to operate, and suitable for photocatalytic treatment of organic sewage; however, the product prepared by the invention has low specific surface area, requires use of an organic solvent, and has a high treatment temperature.
中国专利文献CN 102649060A公开了多孔氧化锌-银复合纳米棒及其制备方法和用途。先将醋酸锌乙醇溶液和二水合草酸乙醇溶液混合后置于密闭状态，于温度为70～90℃下保温至少5h，再对其进行离心、洗涤和干燥的处理，然后，先将得到的草酸锌置于430～470℃下退火至少2h，再将其加入硝酸银乙二醇溶液中，于可见光下搅拌至少15min后，对其进行离心、洗涤和干燥的处理，制得目标产物。但该发明制备得到的复合纳米棒为氧化锌颗粒构筑成的多孔棒状氧化锌的表面负载有银颗粒，是颗粒间的堆积，比表面积相对较低，纳米颗粒活性位点会被覆盖，并且适用于受有机物污染的水中进行可见光催化降解。Chinese patent document CN 102649060A discloses a porous zinc oxide-silver composite nanorod and a preparation method and use thereof. First, the zinc acetate ethanol solution and the oxalic acid dihydrate solution are mixed and placed in a sealed state, and the temperature is maintained at 70 to 90 ° C for at least 5 hours, and then centrifuged, washed and dried, and then the obtained oxalic acid is firstly obtained. The zinc is annealed at 430-470 ° C for at least 2 h, and then added to a silver nitrate glycol solution, stirred under visible light for at least 15 min, and then subjected to centrifugation, washing and drying to obtain a target product. However, the composite nanorods prepared by the invention are composed of zinc oxide particles, and the surface of the porous rod-shaped zinc oxide is loaded with silver particles, which is a deposition between particles, a relatively low specific surface area, and the active sites of the nanoparticles are covered, and is applicable. Visible light photocatalytic degradation in water contaminated with organic matter.
发明内容Summary of the invention
针对现有技术的不足，本发明提供一种简单、绿色、重复性好并能够实现规模生产的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法。In view of the deficiencies of the prior art, the present invention provides a method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material which is simple, green, reproducible and capable of mass production.
本发明的技术方案如下：The technical solution of the present invention is as follows:
一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，包括步骤如下：A method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
(1)将碱式碳酸锌浸泡于贵金属离子的水溶液中，避光搅拌，得含沉淀的反应液；(1) immersing basic zinc carbonate in an aqueous solution of noble metal ions, and stirring in the dark to obtain a reaction liquid containing a precipitate;
(2)步骤(1)得到的反应液中的沉淀经离心洗涤、干燥、煅烧，得复合气敏材料。(2) The precipitate in the reaction liquid obtained in the step (1) is washed by centrifugation, dried, and calcined to obtain a composite gas sensitive material.
根据本发明优选的，所述步骤(1)中碱式碳酸锌的制备方法包括步骤如下：将醋酸锌与尿素溶于水中，110-140℃反应2-6h；经离心、洗涤，干燥，得碱式碳酸锌。According to the preferred method of the present invention, the method for preparing basic zinc carbonate in the step (1) comprises the steps of: dissolving zinc acetate and urea in water, reacting at 110-140 ° C for 2-6 h; centrifuging, washing, and drying. Basic zinc carbonate.
进一步优选的，所述反应温度为120℃，反应时间为2h。Further preferably, the reaction temperature is 120 ° C and the reaction time is 2 h.
进一步优选的，所述醋酸锌与尿素的摩尔比为1:1-5；优选的，所述醋酸锌与尿素的摩尔比为1:2。Further preferably, the molar ratio of zinc acetate to urea is 1:1-5; preferably, the molar ratio of zinc acetate to urea is 1:2.
进一步优选的，所述干燥条件为60℃干燥12h。Further preferably, the drying conditions are dried at 60 ° C for 12 h.
根据本发明优选的，所述步骤(1)中贵金属离子的水溶液为氯金酸、氯铂酸、氯化钯或硝酸银的水溶液。According to the preferred embodiment of the present invention, the aqueous solution of the noble metal ion in the step (1) is an aqueous solution of chloroauric acid, chloroplatinic acid, palladium chloride or silver nitrate.
根据本发明优选的，所述步骤(1)贵金属离子的水溶液中贵金属的质量浓度为0.1wt％-10wt％；优选的，所述步骤(1)贵金属离子的水溶液中中贵金属的质量浓度为1wt％-5wt％。According to the preferred embodiment of the present invention, the mass concentration of the noble metal in the aqueous solution of the precious metal ion in the step (1) is 0.1 wt% to 10 wt%; preferably, the mass concentration of the noble metal in the aqueous solution of the noble metal ion in the step (1) is 1 wt. %-5wt%.
根据本发明优选的，所述步骤(1)中碱式碳酸锌与贵金属的质量比为1:0.05-5。According to the preferred method of the present invention, the mass ratio of the basic zinc carbonate to the noble metal in the step (1) is 1:0.05-5.
根据本发明优选的，所述步骤(1)中浸泡条件为室温下浸泡12-24h。According to the preferred method of the present invention, the soaking condition in the step (1) is soaked for 12-24 hours at room temperature.
根据本发明优选的，所述步骤(2)中干燥条件为60℃干燥12h。 According to the preferred embodiment of the present invention, the drying condition in the step (2) is dried at 60 ° C for 12 h.
根据本发明优选的，所述步骤(2)中煅烧条件为350-500℃，煅烧1-4h。According to the preferred method of the present invention, the calcination condition in the step (2) is 350-500 ° C, and calcination is 1-4 h.
进一步优选的，所述煅烧条件为400℃煅烧2h。Further preferably, the calcination conditions are calcined at 400 ° C for 2 h.
根据本发明优选的，所述步骤(2)中反应液中的沉淀经离心洗涤、干燥、煅烧后，还在氢气氛围下，150-180℃下反应1-4h；优选的，在氢气氛围下，160℃下反应2h。According to the preferred embodiment of the present invention, the precipitate in the reaction liquid in the step (2) is subjected to centrifugal washing, drying, calcination, and further reacted under a hydrogen atmosphere at 150-180 ° C for 1-4 h; preferably, under a hydrogen atmosphere. The reaction was carried out at 160 ° C for 2 h.
当贵金属离子的水溶液为硝酸银水溶液时，所述步骤(2)中反应液中的沉淀经离心洗涤、干燥、煅烧后，还需在氢气氛围下进行还原。When the aqueous solution of the noble metal ion is an aqueous solution of silver nitrate, the precipitate in the reaction liquid in the step (2) is subjected to centrifugal washing, drying, calcination, and further reduction under a hydrogen atmosphere.
本发明借助于室温液相离子交换反应，贵金属离子能够均匀可控的附着在碱式碳酸锌的表面，通过煅烧，碱式碳酸锌分解，产生二氧化碳等气体，生成氧化锌多孔结构；在生成多孔氧化锌纳米片的同时贵金属得以还原成纳米颗粒(单质纳米金、铂、钯可稳定存在；单质纳米银容易部分氧化，借助氢气氛围还原即可)。The invention utilizes a room temperature liquid phase ion exchange reaction, and the noble metal ions can be uniformly and controlly attached to the surface of the basic zinc carbonate, and the calcination, the basic zinc carbonate is decomposed to generate a gas such as carbon dioxide to form a porous structure of zinc oxide; At the same time, the noble metal of the zinc oxide nanosheet can be reduced into nanoparticles (the elemental nano gold, platinum, palladium can be stably existed; the elemental nano silver is easily partially oxidized, and can be reduced by hydrogen atmosphere).
有益效果Beneficial effect
1.本发明制备的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料中，由于液相离子交换反应在碱式碳酸锌表面均匀进行，加之碱式碳酸锌的晶体架构在反应液中相对稳定，因此贵金属离子均匀分布在碱式碳酸锌沉淀表面，故煅烧后贵金属纳米颗粒呈现高度分散状态，粒径分布窄，均匀分布在多孔氧化锌纳米片的表面；通过调控浸泡溶液中贵金属离子的浓度以及浸泡的时间可以调控所制备材料中纳米贵金属的粒径尺寸和负载量；贵金属纳米颗粒表面无保护剂覆盖，活性位点充分暴露，且粒径尺寸小于10nm，可长时间稳定存在，气敏性能优异。1. In the porous zinc oxide nanosheet-loaded high-dispersion nano-precious metal composite gas sensing material prepared by the invention, since the liquid phase ion exchange reaction is uniformly performed on the surface of the basic zinc carbonate, the crystal structure of the basic zinc carbonate is relatively in the reaction liquid. Stable, so the noble metal ions are evenly distributed on the surface of the basic zinc carbonate precipitation, so the noble metal nanoparticles are highly dispersed after calcination, the particle size distribution is narrow, and evenly distributed on the surface of the porous zinc oxide nanosheet; by regulating the precious metal ions in the soaking solution The concentration and the time of soaking can control the particle size and loading of the nano precious metal in the prepared material; the surface of the noble metal nanoparticle is covered with no protective agent, the active site is fully exposed, and the particle size is less than 10 nm, which can exist stably for a long time. Excellent sensitivity.
2.本发明制备的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料中，多孔氧化锌纳米片上孔分布均匀，比表面积大，表面暴露非极性晶面，有利于贵金属纳米颗粒的高分散稳定负载。2. In the porous zinc oxide nanosheet-loaded high-dispersion nano-precious metal composite gas sensing material prepared by the invention, the porous zinc oxide nanosheet has uniform pore distribution, large specific surface area, and surface exposed non-polar crystal plane, which is favorable for noble metal nanoparticles. Disperse stable load.
3.该方法制备的复合气敏材料对VOCs及氯苯类气体的气敏检测响应明显优于单纯的纳米氧化锌材料，并且实现了对多种类气体的高灵敏响应。The composite gas sensing material prepared by the method has better sensitivity to gas sensing of VOCs and chlorobenzene gases than pure nano zinc oxide materials, and achieves a highly sensitive response to various gases.
4.该制备方法绿色简便，重复性好，是一种可规模制造和应用的工艺。4. The preparation method is green, simple and reproducible, and is a process that can be manufactured and applied on a scale.
附图说明DRAWINGS
图1为实施例1制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的透射电镜照片。1 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 1.
图2为实施例2制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的透射电镜照片。2 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 2.
图3为实施例3制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的透射电镜照片。3 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 3.
图4为实施例4制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的透射电镜照片。4 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 4.
图5为实施例5制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的透射电镜照 片。5 is a transmission electron microscope photograph of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 5. sheet.
图6为实施例6制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的透射电镜照片。6 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 6.
图7为实施例1制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的X射线衍射图谱。7 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 1.
图8为实施例2制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的X射线衍射图谱。8 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 2.
图9为实施例3制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的X射线衍射图谱。9 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in Example 3.
图10为实施例4制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的X射线衍射图谱。10 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 4.
图11为实施例5制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的X射线衍射图谱。11 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 5.
图12为实施例6制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的X射线衍射图谱。12 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanopalladium composite gas sensing material prepared in Example 6.
具体实施方式detailed description
下面结合具体实施例对本发明做进一步的说明，但不限于此。The present invention will be further described below in conjunction with specific embodiments, but is not limited thereto.
同时下述实施例中所述实验方法，如无特殊说明，均为常规方法；所述试剂和材料，如无特殊说明，均可从商业途径获得。Meanwhile, the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.
实施例1Example 1
一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，包括步骤如下：A method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
(1)将20ml 0.2mol/L醋酸锌水溶液加入到20ml 0.4mol/L尿素水溶液中，超声分散10min，然后将此混合溶液转移到容积为50mL的内衬为聚四氟乙烯的不锈钢高压釜中，并使其在120℃的烘箱中反应5h。自然冷却至室温，经离心并用去离子水洗涤3次，放入烘箱60℃下干燥12h，即得碱式碳酸锌；(1) 20 ml of 0.2 mol/L zinc acetate aqueous solution was added to 20 ml of 0.4 mol/L urea aqueous solution, ultrasonically dispersed for 10 min, and then the mixed solution was transferred to a volume of 50 mL of a stainless steel autoclave lined with polytetrafluoroethylene. And allowed to react in an oven at 120 ° C for 5 h. Naturally cooled to room temperature, centrifuged and washed 3 times with deionized water, and dried in an oven at 60 ° C for 12 h to obtain basic zinc carbonate;
(2)将0.2g碱式碳酸锌浸泡于20mL质量浓度为1wt％的氯金酸水溶液中，避光室温搅拌12h，得含沉淀的反应液；(2) immersing 0.2 g of basic zinc carbonate in 20 mL of a 1% by weight aqueous solution of chloroauric acid, and stirring at room temperature for 12 hours to obtain a reaction liquid containing a precipitate;
(3)步骤(2)得到的反应液中的沉淀经离心洗涤后，放入烘箱60℃干燥12h，最后在马弗炉中400℃煅烧2h，得复合气敏材料。(3) The precipitate in the reaction liquid obtained in the step (2) is washed by centrifugation, dried in an oven at 60 ° C for 12 h, and finally calcined at 400 ° C for 2 h in a muffle furnace to obtain a composite gas sensitive material.
所制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料中，纳米金的粒径尺寸为2nm左右，负载量约为0.5wt％。In the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-gold composite gas sensing material, the nano gold has a particle size of about 2 nm and a loading of about 0.5 wt%.
图1为本实施例所制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的透射电镜照片，由图可知，纳米金颗粒在多孔氧化锌表面没有团聚，分布均匀，大小均匀。 1 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano gold particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
图7为本实施例制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的X射线衍射图谱，由图可知，除了纤锌矿氧化锌的衍射峰(对应标准卡片JCPDS No.36-1451)之外，出现了比较弱的纳米金衍射峰(对应标准卡片JCPDS No.04-0784，可知为金的(111)和(200)晶面)，没有其它杂峰，因此该复合材料为氧化锌和金的复合材料，没有其它物质结构。7 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nano-gold composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide (corresponding to the standard card JCPDS No. 36- In addition to 1451), a relatively weak nanogold diffraction peak appears (corresponding to the standard card JCPDS No. 04-0784, which is known as the gold (111) and (200) crystal faces), and there are no other peaks, so the composite material is A composite of zinc oxide and gold, with no other material structure.
实施例2Example 2
如实施例1所述，所不同的是步骤(2)中使用质量浓度为3wt％的氯金酸水溶液。As described in Example 1, the difference was that an aqueous solution of chloroauric acid having a mass concentration of 3 wt% was used in the step (2).
所制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料中，纳米金的粒径尺寸为5nm左右，负载量约为2wt％。In the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-gold composite gas sensing material, the nano gold has a particle size of about 5 nm and a loading of about 2 wt%.
图2为本实施例制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的透射电镜照片，由图可知，纳米金颗粒在多孔氧化锌表面没有团聚，分布均匀，大小均匀。2 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano gold particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
图8为本实施例制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的X射线衍射图谱，由图可知，除了纤锌矿氧化锌的衍射峰(对应标准卡片JCPDS No.36-1451)之外，出现了纳米金衍射峰(对应标准卡片JCPDS No.04-0784，可知为金的(111)、(200)和(220)晶面)，没有其它杂峰，因此该复合材料为氧化锌和金的复合材料，没有其它物质结构。8 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide is replaced (corresponding to the standard card JCPDS No. 36- In addition to 1451), a nanogold diffraction peak appeared (corresponding to the standard card JCPDS No. 04-0784, which is known as the (111), (200) and (220) crystal faces of gold), and there are no other peaks, so the composite material As a composite of zinc oxide and gold, there is no other material structure.
实施例3Example 3
如实施例1所述，所不同的是步骤(2)中使用质量浓度为5wt％的氯金酸水溶液。As described in Example 1, the difference was that an aqueous solution of chloroauric acid having a mass concentration of 5 wt% was used in the step (2).
所制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料中，纳米金的粒径尺寸为10nm左右，负载量约为5wt％。In the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-gold composite gas sensing material, the nano gold has a particle size of about 10 nm and a loading of about 5 wt%.
图3为本实施例制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的透射电镜照片，由图可知，纳米金颗粒在多孔氧化锌表面没有团聚，分布均匀，大小均匀。3 is a transmission electron micrograph of a porous zinc oxide nanosheet-loaded highly dispersed nanogold composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano gold particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
图9为本实施例制备的多孔氧化锌纳米片负载高分散纳米金复合气敏材料的X射线衍射图谱，由图可知，除了纤锌矿氧化锌的衍射峰(对应标准卡片JCPDS No.36-1451)之外，出现了有一定强度的纳米金衍射峰(对应标准卡片JCPDS No.04-0784，可知为金的(111)、(200)和(220)晶面)，没有其它杂峰，因此该复合材料为氧化锌和金的复合材料，没有其它物质结构。FIG. 9 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded highly dispersed nano-gold composite gas sensing material prepared in the present embodiment, and the diffraction peak of the wurtzite zinc oxide is not shown in the figure (corresponding to the standard card JCPDS No. 36- In addition to 1451), there is a nano-gold diffraction peak with a certain intensity (corresponding to the standard card JCPDS No. 04-0784, which can be known as the (111), (200) and (220) crystal faces of gold), and there are no other peaks. Therefore, the composite material is a composite material of zinc oxide and gold, and has no other material structure.
实施例4Example 4
一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，包括步骤如下：A method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
(1)将20ml 0.2mol/L醋酸锌水溶液加入到20ml 0.4mol/L尿素水溶液中，超声分散10min，然后将此混合溶液转移到容积为50mL的内衬为聚四氟乙烯的不锈钢高压釜中，并使其在120℃的烘箱中反应5h。自然冷却至室温，经离心并用去离子水洗涤3次，放入烘箱60℃下干燥12h，即得碱式碳酸锌；(1) 20 ml of 0.2 mol/L zinc acetate aqueous solution was added to 20 ml of 0.4 mol/L urea aqueous solution, ultrasonically dispersed for 10 min, and then the mixed solution was transferred to a volume of 50 mL of a stainless steel autoclave lined with polytetrafluoroethylene. And allowed to react in an oven at 120 ° C for 5 h. Naturally cooled to room temperature, centrifuged and washed 3 times with deionized water, and dried in an oven at 60 ° C for 12 h to obtain basic zinc carbonate;
(2)将0.5g碱式碳酸锌浸泡于30mL质量浓度为1wt％的氯化钯水溶液中，避光室温搅拌24h，得含沉淀的反应液； (2) 0.5 g of basic zinc carbonate was immersed in 30 mL of a 1 wt% aqueous solution of palladium chloride, and stirred at room temperature for 24 hours in the dark to obtain a reaction liquid containing a precipitate;
(3)步骤(2)得到的反应液中的沉淀经离心洗涤后，放入烘箱60℃干燥12h，最后在马弗炉中400℃煅烧2h，得复合气敏材料。(3) The precipitate in the reaction liquid obtained in the step (2) is washed by centrifugation, dried in an oven at 60 ° C for 12 h, and finally calcined at 400 ° C for 2 h in a muffle furnace to obtain a composite gas sensitive material.
所制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料中，纳米钯的粒径尺寸为2nm左右，负载量约为0.5wt％。In the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material, the nanopalladium has a particle size of about 2 nm and a loading of about 0.5 wt%.
图4为本实施例制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的透射电镜照片，由图可知，纳米钯颗粒在多孔氧化锌表面没有团聚，分布均匀，大小均匀。4 is a transmission electron micrograph of the porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano-palladium particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
图10为本实施例制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的X射线衍射图谱，由图可知，除了纤锌矿氧化锌的衍射峰(对应标准卡片JCPDS No.36-1451)之外，出现了比较弱的纳米钯衍射峰(对应标准卡片JCPDS No.46-1043，可知为钯的(111)和(200)晶面)，没有其它杂峰，因此该复合材料为氧化锌和钯的复合材料，没有其它物质结构。10 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment, and the diffraction peak of the wurtzite zinc oxide is not shown in the figure (corresponding to the standard card JCPDS No. 36- In addition to 1451), a relatively weak nanopalladium diffraction peak appeared (corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of palladium), and there are no other peaks, so the composite material is A composite of zinc oxide and palladium with no other material structure.
实施例5Example 5
如实施例4所述，所不同的是步骤(2)中使用质量浓度为3wt％的氯化钯水溶液。As described in Example 4, the difference was that a palladium chloride aqueous solution having a mass concentration of 3 wt% was used in the step (2).
所制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料中，纳米钯的粒径尺寸为5nm左右，负载量约为2wt％。In the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material, the nano-palladium has a particle size of about 5 nm and a loading of about 2 wt%.
图5为本实施例制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的透射电镜照片，由图可知，纳米钯颗粒在多孔氧化锌表面没有团聚，分布均匀，大小均匀。FIG. 5 is a transmission electron micrograph of the porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano-palladium particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
图11为本实施例制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的X射线衍射图谱，由图可知，除了纤锌矿氧化锌的衍射峰(对应标准卡片JCPDS No.36-1451)之外，出现了纳米钯衍射峰(对应标准卡片JCPDS No.46-1043，可知为钯的(111)和(200)晶面)，没有其它杂峰，因此该复合材料为氧化锌和钯的复合材料，没有其它物质结构。11 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide (corresponding to the standard card JCPDS No. 36- In addition to 1451), a nanopalladium diffraction peak appeared (corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of palladium), and there are no other peaks, so the composite material is zinc oxide and Palladium composite material, no other material structure.
实施例6Example 6
如实施例4所述，所不同的是步骤(2)中使用质量浓度为5wt％的氯化钯水溶液。As described in Example 4, the difference was that a palladium chloride aqueous solution having a mass concentration of 5 wt% was used in the step (2).
所制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料中，纳米钯的粒径尺寸为8nm左右，负载量约为5wt％。In the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material, the nano-palladium has a particle size of about 8 nm and a loading of about 5 wt%.
图6为本实施例制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的透射电镜照片，由图可知，纳米钯颗粒在多孔氧化锌表面没有团聚，分布均匀，大小均匀。FIG. 6 is a transmission electron micrograph of the porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment. It can be seen from the figure that the nano-palladium particles are not agglomerated on the surface of the porous zinc oxide, and the distribution is uniform and uniform in size.
图12为本实施例制备的多孔氧化锌纳米片负载高分散纳米钯复合气敏材料的X射线衍射图谱，由图可知，除了纤锌矿氧化锌的衍射峰(对应标准卡片JCPDS No.36-1451)之外，出现了有一定强度的纳米钯衍射峰(对应标准卡片JCPDS No.46-1043，可知为钯的(111)和(200)晶面)，没有其它杂峰，因此该复合材料为氧化锌和钯的复合材料，没有其它物质结构。12 is an X-ray diffraction spectrum of a porous zinc oxide nanosheet-loaded high-dispersion nano-palladium composite gas sensing material prepared in the present embodiment, and it can be seen from the figure that the diffraction peak of wurtzite zinc oxide (corresponding to the standard card JCPDS No. 36- In addition to 1451), there is a nanopalladium diffraction peak with a certain intensity (corresponding to the standard card JCPDS No. 46-1043, which is known as the (111) and (200) crystal faces of palladium), and there are no other peaks, so the composite material As a composite of zinc oxide and palladium, there is no other material structure.
实施例7Example 7
一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，包括步骤如下： A method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
(1)将20ml 0.2mol/L醋酸锌水溶液加入到20ml 0.4mol/L尿素水溶液中，超声分散10min，然后将此混合溶液转移到容积为50mL的内衬为聚四氟乙烯的不锈钢高压釜中，并使其在120℃的烘箱中反应5h。自然冷却至室温，经离心并用去离子水洗涤3次，放入烘箱60℃下干燥12h，即得碱式碳酸锌；(1) 20 ml of 0.2 mol/L zinc acetate aqueous solution was added to 20 ml of 0.4 mol/L urea aqueous solution, ultrasonically dispersed for 10 min, and then the mixed solution was transferred to a volume of 50 mL of a stainless steel autoclave lined with polytetrafluoroethylene. And allowed to react in an oven at 120 ° C for 5 h. Naturally cooled to room temperature, centrifuged and washed 3 times with deionized water, and dried in an oven at 60 ° C for 12 h to obtain basic zinc carbonate;
(2)将0.5g碱式碳酸锌浸泡于30mL质量浓度为1wt％的硝酸银水溶液中，避光室温搅拌24h，得含沉淀的反应液；(2) 0.5 g of basic zinc carbonate was immersed in 30 mL of a 1% by weight aqueous solution of silver nitrate, and stirred at room temperature for 24 hours in the dark to obtain a reaction liquid containing a precipitate;
(3)步骤(2)得到的反应液中的沉淀经离心洗涤后，放入烘箱60℃干燥12h，然后在马弗炉中400℃煅烧2h；然后，将产物放入瓷舟，在管式炉中160℃氢气氛围下还原2h，得复合气敏材料。(3) The precipitate in the reaction liquid obtained in the step (2) is washed by centrifugation, dried in an oven at 60 ° C for 12 h, and then calcined at 400 ° C for 2 h in a muffle furnace; then, the product is placed in a porcelain boat, in a tube type. The composite gas-sensitive material was obtained by reduction in a furnace at 160 ° C for 2 h under a hydrogen atmosphere.
所制备的多孔氧化锌纳米片负载高分散纳米银复合气敏材料中，纳米银的粒径尺寸为2nm左右，负载量约为0.5wt％。In the prepared porous zinc oxide nanosheet-loaded highly dispersed nanosilver composite gas sensing material, the nano silver has a particle size of about 2 nm and a loading of about 0.5 wt%.
实施例8Example 8
如实施例1所述，所不同的是步骤(2)中使用质量浓度为1wt％的氯铂酸水溶液。As described in Example 1, the difference was that an aqueous solution of chloroplatinic acid having a mass concentration of 1% by weight was used in the step (2).
实施例9Example 9
如实施例1所述，所不同的是步骤(2)中使用质量浓度为3wt％的氯铂酸水溶液。As described in Example 1, the difference was that an aqueous solution of chloroplatinic acid having a mass concentration of 3 wt% was used in the step (2).
实施例10Example 10
如实施例1所述，所不同的是步骤(2)中使用质量浓度为5wt％的氯铂酸水溶液。As described in Example 1, the difference was that an aqueous solution of chloroplatinic acid having a mass concentration of 5 wt% was used in the step (2).
实施例11Example 11
如实施例7所述，所不同的是步骤(2)中使用质量浓度为3wt％的硝酸银水溶液。As described in Example 7, the difference was that a silver nitrate aqueous solution having a mass concentration of 3 wt% was used in the step (2).
实施例12Example 12
如实施例7所述，所不同的是步骤(2)中使用质量浓度为5wt％的硝酸银水溶液。As described in Example 7, the difference was that a silver nitrate aqueous solution having a mass concentration of 5 wt% was used in the step (2).
实施例13Example 13
一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，包括步骤如下：A method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
(1)将20ml 0.2mol/L醋酸锌水溶液加入到20ml 0.2mol/L尿素水溶液中，超声分散10min，然后将此混合溶液转移到容积为50mL的内衬为聚四氟乙烯的不锈钢高压釜中，并使其在110℃的烘箱中反应6h。自然冷却至室温，经离心并用去离子水洗涤3次，放入烘箱60℃下干燥12h，即得碱式碳酸锌；(1) 20 ml of 0.2 mol/L zinc acetate aqueous solution was added to 20 ml of 0.2 mol/L urea aqueous solution, ultrasonically dispersed for 10 min, and then the mixed solution was transferred to a volumetric 50 mL stainless steel autoclave lined with polytetrafluoroethylene. And allowed to react in an oven at 110 ° C for 6 h. Naturally cooled to room temperature, centrifuged and washed 3 times with deionized water, and dried in an oven at 60 ° C for 12 h to obtain basic zinc carbonate;
(2)将0.2g碱式碳酸锌浸泡于20mL质量浓度为0.1wt％的氯金酸水溶液中，避光室温搅拌20h，得含沉淀的反应液；(2) immersing 0.2 g of basic zinc carbonate in 20 mL of a 0.1% by weight aqueous solution of chloroauric acid, and stirring at room temperature for 20 hours in the dark to obtain a reaction liquid containing a precipitate;
(3)步骤(2)得到的反应液中的沉淀经离心洗涤后，放入烘箱60℃干燥12h，最后在马弗炉中350℃煅烧4h，得复合气敏材料。(3) The precipitate in the reaction liquid obtained in the step (2) is washed by centrifugation, dried in an oven at 60 ° C for 12 h, and finally calcined at 350 ° C for 4 h in a muffle furnace to obtain a composite gas sensitive material.
实施例14Example 14
一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，包括步骤如 下：Method for synthesizing porous zinc oxide nanosheet loaded high dispersion nano precious metal composite gas sensing material, including steps under:
(1)将20ml 0.2mol/L醋酸锌水溶液加入到20ml 1mol/L尿素水溶液中，超声分散10min，然后将此混合溶液转移到容积为50 mL的内衬为聚四氟乙烯的不锈钢高压釜中，并使其在140℃的烘箱中反应3h。自然冷却至室温，经离心并用去离子水洗涤3次，放入烘箱60℃下干燥12h，即得碱式碳酸锌；(1) 20 ml of 0.2 mol/L zinc acetate aqueous solution was added to 20 ml of 1 mol/L urea aqueous solution, ultrasonically dispersed for 10 min, and then the mixed solution was transferred to a volumetric 50 mL stainless steel autoclave lined with polytetrafluoroethylene. And allowed to react in an oven at 140 ° C for 3 h. Naturally cooled to room temperature, centrifuged and washed 3 times with deionized water, and dried in an oven at 60 ° C for 12 h to obtain basic zinc carbonate;
(2)将0.2g碱式碳酸锌浸泡于20mL质量浓度为10wt％的氯金酸水溶液中，避光室温搅拌18h，得含沉淀的反应液；(2) immersing 0.2 g of basic zinc carbonate in 20 mL of a 10% by weight aqueous solution of chloroauric acid, and stirring at room temperature for 18 hours in the dark to obtain a reaction liquid containing a precipitate;
(3)步骤(2)得到的反应液中的沉淀经离心洗涤后，放入烘箱60℃干燥12h，最后在马弗炉中500℃煅烧1h，得复合气敏材料。(3) The precipitate in the reaction liquid obtained in the step (2) is washed by centrifugation, dried in an oven at 60 ° C for 12 h, and finally calcined at 500 ° C for 1 h in a muffle furnace to obtain a composite gas sensitive material.
对比例1Comparative example 1
一种多孔氧化锌纳米片，制备步骤如下：A porous zinc oxide nanosheet, the preparation steps are as follows:
(1)将20ml 0.2mol/L醋酸锌水溶液加入到20ml 0.4mol/L尿素水溶液中，超声分散10min，然后将此混合溶液转移到容积为50mL的内衬为聚四氟乙烯的不锈钢高压釜中，并使其在120℃的烘箱中反应5h。自然冷却至室温，经离心并用去离子水洗涤3次，放入烘箱60℃下干燥12h，即得碱式碳酸锌；(1) 20 ml of 0.2 mol/L zinc acetate aqueous solution was added to 20 ml of 0.4 mol/L urea aqueous solution, ultrasonically dispersed for 10 min, and then the mixed solution was transferred to a volume of 50 mL of a stainless steel autoclave lined with polytetrafluoroethylene. And allowed to react in an oven at 120 ° C for 5 h. Naturally cooled to room temperature, centrifuged and washed 3 times with deionized water, and dried in an oven at 60 ° C for 12 h to obtain basic zinc carbonate;
(2)步骤(1)得到的碱式碳酸锌在马弗炉中400℃煅烧2h，得多孔氧化锌纳米片。(2) The basic zinc carbonate obtained in the step (1) is calcined in a muffle furnace at 400 ° C for 2 hours to obtain a porous zinc oxide nanosheet.
对比例2Comparative example 2
一种多孔氧化锌纳米片负载纳米氧化钴复合气敏材料的合成方法，包括步骤如下：A method for synthesizing porous zinc oxide nanosheet-loaded nanometer cobalt oxide composite gas sensing material comprises the following steps:
(1)将20ml 0.2mol/L醋酸锌水溶液加入到20ml 0.4mol/L尿素水溶液中，超声分散10min，然后将此混合溶液转移到容积为50mL的内衬为聚四氟乙烯的不锈钢高压釜中，并使其在120℃的烘箱中反应5h。自然冷却至室温，经离心并用去离子水洗涤3次，放入烘箱60℃下干燥12h，即得碱式碳酸锌；(1) 20 ml of 0.2 mol/L zinc acetate aqueous solution was added to 20 ml of 0.4 mol/L urea aqueous solution, ultrasonically dispersed for 10 min, and then the mixed solution was transferred to a volume of 50 mL of a stainless steel autoclave lined with polytetrafluoroethylene. And allowed to react in an oven at 120 ° C for 5 h. Naturally cooled to room temperature, centrifuged and washed 3 times with deionized water, and dried in an oven at 60 ° C for 12 h to obtain basic zinc carbonate;
(2)将0.2g碱式碳酸锌浸泡于20mL质量浓度为10wt％的醋酸钴水溶液中，避光室温搅拌24h，得含沉淀的反应液；(2) immersing 0.2 g of basic zinc carbonate in 20 mL of a 10% by weight aqueous solution of cobalt acetate, and stirring at room temperature for 24 hours in the dark to obtain a reaction liquid containing a precipitate;
(3)步骤(2)得到的反应液中的沉淀经离心洗涤后，放入烘箱60℃干燥12h，最后在马弗炉中400℃煅烧4h，得多孔氧化锌纳米片负载纳米氧化钴复合气敏材料。(3) The precipitate in the reaction liquid obtained in the step (2) is washed by centrifugation, dried in an oven at 60 ° C for 12 h, and finally calcined at 400 ° C for 4 h in a muffle furnace to obtain a porous zinc oxide nanosheet-loaded nano-oxide cobalt composite gas. Sensitive material.
试验例1Test example 1
将实施例1-14以及对比例1、2所制备的气敏材料进行气敏性能测试，测试方法如下：The gas sensing materials prepared in Examples 1-14 and Comparative Examples 1 and 2 were tested for gas sensitivity, and the test methods were as follows:
1.测试所用仪器为郑州炜盛电子科技有限公司所生产的WS-30A型气敏测试仪，气敏元件则是按照传统方法制成的旁热式烧结型元件。1. The instrument used for testing is the WS-30A gas sensitivity tester produced by Zhengzhou Yusheng Electronic Technology Co., Ltd., and the gas sensor is a side-heating sintered component made according to the traditional method.
2.在研钵中加入0.2g合成的气敏材料样品，滴入少量乙醇至研磨均匀成糊状，用细毛刷均匀地涂于两端带有金电极的氧化铝陶瓷管***。2. Add 0.2 g of synthetic gas-sensitive material sample to the mortar, drop a small amount of ethanol until it is ground into a paste, and apply evenly on the periphery of the alumina ceramic tube with gold electrodes at both ends with a fine brush.
3.待样品在陶瓷管上完全干燥后，将4个铂丝引线接头焊接在元件底座上，再将加热 丝穿过陶瓷管，并将加热丝两端也焊在元件底座上制做成气敏元件，然后将元件置于老化台上450℃老化5-7天。3. After the sample is completely dried on the ceramic tube, solder the four platinum wire lead joints to the component base and heat it. The wire passes through the ceramic tube, and both ends of the heating wire are also welded to the component base to form a gas sensor, and then the component is placed on an aging table and aged at 450 ° C for 5-7 days.
4.将气相待测物注入测试仓后，通过记录与气敏元件串联的负载电阻上的电压来反映气敏元件的敏感特性。气敏元件的灵敏度响应值(S)被定义为S＝Ra/Rg，Ra和Rg分别为气敏元件在空气中和被测气体中的电阻值。4. After injecting the gas phase analyte into the test chamber, the sensitivity of the gas sensor is reflected by recording the voltage across the load resistor in series with the gas sensor. The sensitivity response value (S) of the gas sensor is defined as S = Ra / Rg, and Ra and Rg are the resistance values of the gas sensor in the air and the gas to be measured, respectively.
实施例1-14以及对比例1、2所制备的气敏材料的气敏性能测试结果如下表所示：The gas sensitivity test results of the gas sensing materials prepared in Examples 1-14 and Comparative Examples 1 and 2 are shown in the following table:
Figure PCTCN2017109017-appb-000001
Figure PCTCN2017109017-appb-000001
Figure PCTCN2017109017-appb-000002
Figure PCTCN2017109017-appb-000002
Figure PCTCN2017109017-appb-000003
Figure PCTCN2017109017-appb-000003
注：--表明测不出相应数据。Note: -- indicates that the corresponding data cannot be measured.
综合分析，所制备的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料(例如，实施例1-14)对VOCs及氯苯类气体的气敏检测响应值明显优于单纯的纳米氧化锌以及氧化锌负载纳米氧化钴的材料(例如，对比例1、2)，并且实现了对多种类气体的高灵敏响应，响应和恢复时间也较快。因此，本发明的方法具有潜在的开发应用价值。 Comprehensive analysis, the prepared porous zinc oxide nanosheet-loaded high-dispersion nano-precious metal composite gas sensing material (for example, Examples 1-14) has a significantly better gas sensing detection response value for VOCs and chlorobenzene gases than pure nano zinc oxide. And zinc oxide-loaded nano-cobalt oxide materials (for example, Comparative Examples 1, 2), and achieve a highly sensitive response to a variety of gases, response and recovery time is also faster. Therefore, the method of the present invention has potential development and application value.

Claims (10)

  1. 一种多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，包括步骤如下：A method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material comprises the following steps:
    (1)将碱式碳酸锌浸泡于贵金属离子的水溶液中，避光搅拌，得含沉淀的反应液；(1) immersing basic zinc carbonate in an aqueous solution of noble metal ions, and stirring in the dark to obtain a reaction liquid containing a precipitate;
    (2)步骤(1)得到的反应液中的沉淀经离心洗涤、干燥、煅烧，得复合气敏材料。(2) The precipitate in the reaction liquid obtained in the step (1) is washed by centrifugation, dried, and calcined to obtain a composite gas sensitive material.
  2. 根据权利要求1所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述步骤(1)中碱式碳酸锌的制备方法包括步骤如下：将醋酸锌与尿素溶于水中，110-140℃反应2-6h；经离心、洗涤，干燥，得碱式碳酸锌。The method for synthesizing a porous zinc oxide nanosheet-loaded high-dispersion nano precious metal composite gas sensing material according to claim 1, wherein the method for preparing the basic zinc carbonate in the step (1) comprises the following steps: It is dissolved in water with urea and reacted at 110-140 ° C for 2-6 h; it is centrifuged, washed and dried to obtain basic zinc carbonate.
  3. 根据权利要求2所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述反应温度为120℃，反应时间为2h。The method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material according to claim 2, wherein the reaction temperature is 120 ° C and the reaction time is 2 h.
  4. 根据权利要求2所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述醋酸锌与尿素的摩尔比为1:1-5；The method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material according to claim 2, wherein the molar ratio of zinc acetate to urea is 1:1-5;
    优选的，所述醋酸锌与尿素的摩尔比为1:2。Preferably, the molar ratio of zinc acetate to urea is 1:2.
  5. 根据权利要求1所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述步骤(1)中贵金属离子的水溶液为氯金酸、氯铂酸、氯化钯或硝酸银的水溶液。The method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material according to claim 1, wherein the aqueous solution of the noble metal ion in the step (1) is chloroauric acid, chloroplatinic acid or chlorine. An aqueous solution of palladium or silver nitrate.
  6. 根据权利要求1所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述步骤(1)贵金属离子的水溶液中贵金属的质量浓度为0.1wt％-10wt％；The method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material according to claim 1, wherein the mass concentration of the noble metal in the aqueous solution of the noble metal ion in the step (1) is 0.1 wt% to 10 wt% %;
    优选的，所述步骤(1)贵金属离子的水溶液中贵金属的质量浓度为1wt％-5wt％。Preferably, the mass concentration of the noble metal in the aqueous solution of the noble metal ion in the step (1) is from 1% by weight to 5% by weight.
  7. 根据权利要求1所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述步骤(1)中碱式碳酸锌与贵金属的质量比为1:0.05-5。The method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material according to claim 1, wherein the mass ratio of the basic zinc carbonate to the noble metal in the step (1) is 1:0.05- 5.
  8. 根据权利要求1所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述步骤(1)中浸泡条件为室温下浸泡12-24h。The method for synthesizing a porous zinc oxide nanosheet-loaded high-dispersion nano-precious metal composite gas sensing material according to claim 1, wherein the immersion condition in the step (1) is immersion for 12-24 hours at room temperature.
  9. 根据权利要求1所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述步骤(2)中煅烧条件为350-500℃，煅烧1-4h；The method for synthesizing a porous zinc oxide nanosheet-loaded high-dispersion nano-precious metal composite gas sensing material according to claim 1, wherein the calcination condition in the step (2) is 350-500 ° C, calcination 1-4 h;
    优选的，所述煅烧条件为400℃煅烧2h。Preferably, the calcination conditions are calcined at 400 ° C for 2 h.
  10. 根据权利要求1所述的多孔氧化锌纳米片负载高分散纳米贵金属复合气敏材料的合成方法，其特征在于，所述步骤(2)中反应液中的沉淀经离心洗涤、干燥、煅烧后，还在氢气氛围下，150-180℃下反应1-4h；The method for synthesizing a porous zinc oxide nanosheet-loaded highly dispersed nano precious metal composite gas sensing material according to claim 1, wherein the precipitate in the reaction liquid in the step (2) is subjected to centrifugal washing, drying, and calcination, Still reacting at 150-180 ° C for 1-4 h under a hydrogen atmosphere;
    优选的，在氢气氛围下，160℃下反应2h。 Preferably, the reaction is carried out at 160 ° C for 2 h under a hydrogen atmosphere.
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