CN110412088B - In doping based on Au2O3Xanthate gas sensitive element of nanosphere and preparation method thereof - Google Patents

In doping based on Au2O3Xanthate gas sensitive element of nanosphere and preparation method thereof Download PDF

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CN110412088B
CN110412088B CN201910728452.4A CN201910728452A CN110412088B CN 110412088 B CN110412088 B CN 110412088B CN 201910728452 A CN201910728452 A CN 201910728452A CN 110412088 B CN110412088 B CN 110412088B
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沈岩柏
赵思凯
钟祥熙
翁绍涵
韩聪
方萍
魏德洲
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Northeastern University China
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    • 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
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    • G01N27/127—Composition of the body, e.g. the composition of its sensitive layer comprising nanoparticles

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Abstract

The invention discloses In doped with Au2O3A nano-sphere xanthate gas sensitive element and a preparation method thereof belong to the field of gas sensors made of metal oxide semiconductor materials. The method takes indium nitrate as an indium source and chloroauric acid as a gold source, and adopts a hydrothermal method to prepare Au-doped In with a hexagonal crystal structure and a diameter of 75-125 nm2O3Nanospheres. Doping the prepared Au with In2O3The nanospheres are dispersed in an ethanol solution to prepare gas-sensitive slurry, and then the gas-sensitive slurry is uniformly coated on the surface of an electrode element to prepare the gas-sensitive element. The Au of the invention is doped with In2O3The synthesis method of the nanosphere is simple, low in cost, free of pollution and stable in structure. The gas sensor disclosed by the invention is high in sensitivity, has good response and recovery characteristics, good response reversibility, repeatability and stability, can fill the blank of quantitative detection of the gas in the current market, and has important significance for guaranteeing the life health and safety of workers in a flotation workshop of a concentrating mill.

Description

In doping based on Au2O3Xanthate gas sensitive element of nanosphere and preparation method thereof
Technical Field
The invention belongs to the field of metal oxide semiconductor gas sensors, and particularly relates to an In doping method based on Au2O3A xanthate gas sensitive element of nanospheres and a preparation method thereof.
Background
In the comprehensive utilization process of mineral resources, useful elements in the ores are firstly enriched. Common sorting methods include gravity separation, magnetic separation, flotation and the like. The flotation is an ore sorting method with wide application, and the basic principle is that the difference of the physicochemical properties of the surfaces of different minerals is utilized to enable the minerals to be selectively attached to air bubbles in ore pulp and float to the surface of the ore pulp along with the air bubbles, so that useful minerals are separated from gangue. In order to control the physicochemical properties of the ore surface and the properties of the pulp during the flotation operation, certain flotation agents must be added to the pulp. Xanthate, the most common flotation agent, is commonly used in the flotation of sulphide ores. However, xanthate solutions are easily decomposed and volatilized, and their volatile gases have strong pungent odors, have severe irritating effects on eyes, skin, respiratory system, central and peripheral nervous systems, and can cause anesthesia or mental abnormalities when exposed to acute high concentrations (> 0.05%). Therefore, the prepared high-performance gas sensor is used for quantitatively monitoring xanthate gas in a flotation workshop and has important significance for protecting the life health of workers in the flotation workshop.
There are many different types of gas sensors on the market, such as semiconductor type, catalytic combustion type, photochemical type, electrochemical type, etc., and the types of detection gases cover most of the common gases. However, a high-performance gas sensor capable of effectively detecting xanthate gas has not been developed.
Disclosure of Invention
Aiming at the detection means that the flotation workshop of the prior concentrating mill is lack of effective xanthate gas, the invention provides a method based on Au doping In2O3A xanthate gas sensitive element of nanospheres and a preparation method thereof. Aims to control the synthesis of Au-doped In with good dispersibility and larger specific surface area by optimizing preparation process parameters2O3The nanospheres are used as gas-sensitive materials to prepare the gas-sensitive element capable of detecting the xanthate gas in real time, so that accidents that workers in a flotation workshop are harmed due to overhigh concentration of the xanthate gas are effectively prevented.
The invention provides In based on Au doping2O3The gas-sensitive element mainly comprises an electrode element and Au-doped In uniformly coated on the electrode element2O3Composition of nanospheres, said Au being doped with In2O3The nanospheres are hexagonal crystal structures, 75-125 nm in diameter, rough and porous in surface, uniform in appearance and good in dispersity.
Further, in the above technical solution, the electrode element is a ceramic electrode.
Further, in the above technical solution, the electrode element is in the shape of a tubular electrode or a planar electrode.
Further, In the above technical solution, the Au is doped with In2O3The nanospheres are prepared as follows:
sequentially adding indium nitrate, citric acid monohydrate and urea into a mixed solution of deionized water and ethylene glycol according to a molar ratio of 1:2:1.5, wherein the volume ratio of the deionized water to the ethylene glycol is 1:1, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolved;
secondly, slowly adding a certain amount of chloroauric acid solution with the molar ratio of 1: 100-5: 100 to indium nitrate into the solution obtained in the first step in the stirring process;
transferring the solution obtained in the step II to a hydrothermal reaction kettle, and then placing the hydrothermal reaction kettle in an oven to react for 6-24 hours at the temperature of 120-180 ℃;
fourthly, after the reaction is finished, after the hydrothermal reaction kettle is cooled to room temperature, washing and drying a product obtained by the reaction, and then carrying out heat treatment In a tubular furnace at the temperature of 200-400 ℃ for 2-5 h to obtain Au-doped In2O3Nanospheres.
Further, in the technical scheme, the washing and drying processes in the step IV are that the precipitated product is washed by deionized water and absolute ethyl alcohol for at least 2 times and then is dried in a drying oven at 30-80 ℃ for 12-48 h.
The invention also provides In doped based on Au2O3The preparation method of the xanthate gas sensor of the nanosphere comprises the following steps:
sequentially adding indium nitrate, citric acid monohydrate and urea into a mixed solution of deionized water and ethylene glycol according to the molar ratio of 1:2:1.5, wherein the volume ratio of the deionized water to the ethylene glycol is 1:1, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolvedSolving; slowly adding a certain amount of chloroauric acid solution with the molar ratio of 1: 100-5: 100 to indium nitrate into the solution during stirring; transferring the obtained solution to a hydrothermal reaction kettle, and then placing the hydrothermal reaction kettle in an oven to react for 6-24 hours at the temperature of 120-180 ℃; after the reaction is finished, after the hydrothermal reaction kettle is cooled to room temperature, washing and drying a product obtained by the reaction, and carrying out heat treatment In a tubular furnace at the temperature of 200-400 ℃ for 2-5 h to obtain Au-doped In2O3Nanospheres;
② doping In with Au obtained In the step I2O3Dispersing the nanospheres into absolute ethyl alcohol, grinding for 10min by a wet method, and mixing into pasty slurry to obtain gas-sensitive slurry;
uniformly coating the gas-sensitive slurry obtained in the step two on the surface of an electrode element;
fourthly, coating Au In the third step to dope In2O3Connecting the electrode element of the nanosphere to a hexagonal base, then installing the electrode element on an aging table of the gas sensitive element, and aging the electrode element for 12-24 hours at 300 ℃ to obtain the In doped Au2O3A nano-sphere xanthate gas sensor.
Further, in the technical scheme, the washing and drying processes in the step I are that the precipitated product is washed for at least 2 times by deionized water and absolute ethyl alcohol respectively and then is dried in a drying oven for 12-48 hours at the temperature of 30-80 ℃.
Furthermore, In the above technical solution, the wet grinding In the step (II) is specifically performed by doping In with Au dispersed In ethanol2O3The nanospheres were placed in an agate mortar and ground into a paste slurry in a fluid environment with ethanol.
Furthermore, In the above technical scheme, the slurry coating method In the third step is to dip the Au-doped In by using a crochet pen2O3And (3) uniformly coating the nanosphere slurry on the electrode element so that the surface of the electrode element is completely covered and the thickness of the electrode element is uniform.
Compared with the prior art, the invention has the characteristics and beneficial effects that:
the invention provides Au-doped In2O3A synthetic method of nanospheres and a gas sensor for detecting xanthate gas based on the material. Firstly, a high-performance gas sensor capable of effectively detecting xanthate gas is lacked in the current market, so that the gas sensor can fill the gap. The gas sensor has high sensitivity, good stability, selectivity and repeatability. Meanwhile, the gas-sensitive material used by the gas-sensitive element has the characteristics of simple synthesis method, low cost, stable structure and the like.
Drawings
FIG. 1 shows Au-doped In prepared by the present invention2O3X-ray diffraction patterns of nanospheres;
FIG. 2 shows Au-doped In prepared by the present invention2O3Scanning electron microscope photographs (a) at low magnification and (b) at high magnification of the nanospheres;
FIG. 3 is a schematic structural view of the ceramic electrode according to embodiments 1 to 4; wherein, 1: a ceramic tube; 2: a gas sensitive coating; 3: heating resistance wires; 4: gold film; 5: a platinum lead wire; 6: a hexagonal base;
FIG. 4 is a graph showing the relationship between the sensitivity of the gas sensor prepared according to the present invention to 20ppm xanthate gas and the operating temperature;
FIG. 5 is a dynamic response curve of the gas sensor prepared by the invention to xanthate gas with different concentrations at the working temperature of 300 ℃;
FIG. 6 is a graph of the sensitivity of the gas sensor prepared according to the present invention to different gases to be detected at a working temperature of 300 ℃;
FIG. 7 is a graph showing the repeatability of the gas sensor prepared according to the present invention for 6 cycles of 50ppm xanthate gas at a working temperature of 300 ℃.
Detailed Description
The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.
The test methods described in the following examples are all conventional methods unless otherwise specified; the reagents, materials and equipment are commercially available, unless otherwise specified.
The gas-sensitive test system in the following embodiment is a Weisheng scientific and technological WS-30A type gas-sensitive test system; the aging table is a Weisheng science and technology TS-60 type aging table.
Example 1
In doping based on Au as described In this example2O3The structure schematic diagram of the nano-sphere xanthate gas sensitive element is shown in fig. 3, and the nano-sphere xanthate gas sensitive element comprises a ceramic tube 1, a gas sensitive coating 2, a heating resistance wire 3, a gold film 4, a platinum lead 5 and a hexagonal base 6, wherein the gold film 4 covers two ends of the ceramic tube 1 to form a ceramic tube electrode, the gas sensitive coating 2 is uniformly coated on the surfaces of the whole ceramic tube 1 and the gold film 4, and the heating resistance wire 3 transversely penetrates through the ceramic tube 1 and is welded on the heating electrode of the hexagonal base 6; one end of a platinum lead 4 is welded on the surface of the gold film 4, and the other end is welded on four measuring electrodes of the hexagonal base 6 to prepare In based on Au doping2O3A nano-sphere xanthate gas sensor. The gas-sensitive coating 2 is prepared by doping Au with In2O3Nanospheres of Au doped with In2O3The nanospheres are uniform in appearance and good in dispersity, and the diameter of the nanospheres is 75-125 nm. The Au is doped with In2O3The preparation process of the nanosphere comprises the following steps:
adding 1mmol of indium nitrate, 2mmol of citric acid monohydrate and 1.5mmol of urea into a mixed solution of 15ml of deionized water and 15ml of ethylene glycol in sequence, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolved.
② slowly adding 3ml of chloroauric acid solution (4.256g/L) into the solution obtained in the step (I) while stirring.
And thirdly, transferring the solution obtained in the second step to a polytetrafluoroethylene hydrothermal reaction kettle, and then placing the kettle in an oven to react for 12 hours at the temperature of 160 ℃.
After the reaction is finished, after the hydrothermal reaction kettle is naturally cooled to room temperature, cleaning the product obtained by the reaction for at least 2 times by using deionized water and ethanol to remove impurity ions in the product.
Fifthly, drying the cleaned product In a vacuum drying oven for 12 hours at the temperature of 30 ℃, and then carrying out heat treatment In a tubular furnace for 4 hours at the temperature of 400 ℃ to obtain Au-doped In2O3Nanospheres.
FIG. 1 shows Au-doped In prepared2O3XRD pattern of nanospheres. As can be seen from the figure, Au-doped In was prepared2O3The nanosphere consists of cubic phase simple substance Au and hexagonal phase In2O3The composition and crystallinity are good. FIG. 2 shows Au-doped In prepared2O3Scanning electron micrographs of nanospheres. As can be seen, the obtained product is spherical, has the diameter of 75-125 nm, has a rough and porous surface and consists of In2O3The nano particles are formed, and the dispersity is better.
In doping based on Au2O3The preparation method of the xanthate gas sensor of the nanosphere comprises the following steps:
(ii) 0.01g of the Au was doped with In2O3Dispersing the nanospheres into 10mL of absolute ethyl alcohol, grinding in an agate mortar for 10min in a fluid environment with ethyl alcohol, and mixing into pasty slurry to obtain gas-sensitive slurry.
Uniformly coating the gas-sensitive slurry on the surface of the ceramic tube electrode to prepare a gas-sensitive coating, wherein the coating method comprises the step of dipping a crochet pen with Au-doped In2O3And (3) uniformly coating the nanosphere slurry on the electrode element so that the surface of the electrode element is completely covered and the thickness of the electrode element is uniform.
Thirdly, welding the prepared electrode on a hexagonal base, and then aging the electrode on an aging table of a gas sensitive element for 24 hours at 300 ℃ to obtain the In based on Au doping2O3A nano-sphere xanthate gas sensor.
Fig. 4 is a graph showing the relationship between the sensitivity of the gas sensor prepared by the present invention to 20ppm xanthate gas and the operating temperature, and it can be seen that the sensitivity of the gas sensor to xanthate gas with the same concentration shows a trend of increasing first and then decreasing with the increase of the operating temperature, and the maximum sensitivity to xanthate gas is obtained at the operating temperature of 300 ℃. Fig. 5 shows the sensitivity of the gas sensor to xanthate gas with different concentrations at the working temperature of 300 ℃, and it can be seen that the sensitivity of the gas sensor increases with the increase of the concentration of the xanthate gas. Meanwhile, the gas sensor also shows excellent reversibility, repeatability and stability. FIG. 6 is a graph of the sensitivity of the gas sensor to different gases at an operating temperature of 300 ℃. The sensitivity of the gas sensor to xanthate gas is far higher than that of other common interfering gases, which shows that the gas sensor has good selectivity to xanthate gas and can be used for specific identification of xanthate gas. FIG. 7 is a graph showing the repeatability of the gas sensor at an operating temperature of 300 ℃ for 6 cycles of 50ppm xanthate gas. It can be seen that the response and recovery characteristics of the gas sensor are almost the same in 6 consecutive test cycles, with less fluctuation. Meanwhile, after 6 times of continuous tests, the resistance of the alloy can still be quickly restored to the initial value, indicating that the alloy has excellent stability.
Example 2
In doping based on Au as described In this example2O3The structure schematic diagram of the nano-sphere xanthate gas sensitive element is shown in fig. 3, and the nano-sphere xanthate gas sensitive element comprises a ceramic tube 1, a gas sensitive coating 2, a heating resistance wire 3, a gold film 4, a platinum lead 5 and a hexagonal base 6, wherein the gold film 4 covers two ends of the ceramic tube 1 to form a ceramic tube electrode, the gas sensitive coating 2 is uniformly coated on the surfaces of the whole ceramic tube 1 and the gold film 4, and the heating resistance wire 3 transversely penetrates through the ceramic tube 1 and is welded on the heating electrode of the hexagonal base 6; one end of a platinum lead 4 is welded on the surface of the gold film 4, and the other end is welded on four measuring electrodes of the hexagonal base 6 to prepare In based on Au doping2O3A nano-sphere xanthate gas sensor. The gas-sensitive coating 2 is prepared by doping Au with In2O3Nanospheres of Au doped with In2O3The nanospheres are uniform in appearance and good in dispersity, and the diameter of the nanospheres is 75-125 nm. The Au is doped with In2O3The preparation process of the nanosphere comprises the following steps:
adding 1mmol of indium nitrate, 2mmol of citric acid monohydrate and 1.5mmol of urea into a mixed solution of 15ml of deionized water and 15ml of ethylene glycol in sequence, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolved.
② slowly adding 3ml of chloroauric acid solution (4.256g/L) into the solution obtained in the step (I) while stirring.
And thirdly, transferring the solution obtained in the step two to a polytetrafluoroethylene hydrothermal reaction kettle, and then placing the kettle in an oven to react for 8 hours at the temperature of 160 ℃.
After the reaction is finished, after the hydrothermal reaction kettle is naturally cooled to room temperature, washing the product obtained by the reaction for at least 2 times by using deionized water and ethanol to remove impurity ions in the product.
Fifthly, drying the cleaned product In a vacuum drying oven for 15h at 40 ℃, and then carrying out heat treatment In a tubular furnace for 4h at 400 ℃ to obtain Au-doped In2O3Nanospheres.
The obtained Au-doped In2O3The nanosphere has a hexagonal phase crystal structure and good crystallinity. The nanosphere has a diameter of 75-125 nm, a rough and porous surface and is composed of In2O3The nano particles are formed, and the dispersity is better.
In doping based on Au2O3The preparation method of the xanthate gas sensor of the nanosphere comprises the following steps:
(ii) 0.01g of the Au was doped with In2O3Dispersing 10mL of nanospheres into absolute ethyl alcohol, grinding in an agate mortar for 10min in a fluid environment with ethyl alcohol, and mixing into pasty slurry to obtain gas-sensitive slurry.
Uniformly coating the gas-sensitive slurry on the surface of an electrode element to prepare a gas-sensitive coating, wherein the coating method comprises the step of dipping a crochet pen with Au-doped In2O3And (3) uniformly coating the nanosphere slurry on the electrode element so that the surface of the electrode element is completely covered and the thickness of the electrode element is uniform.
Thirdly, welding the prepared electrode on a hexagonal base, and aging the electrode on an aging table of a gas sensitive element for 24 hours at 300 ℃ to obtain the In doped based on Au2O3A nano-sphere xanthate gas sensor.
Through detection, the gas sensor prepared by the embodiment has good gas-sensitive property to xanthate gas at the working temperature of 200-325 ℃.
Example 3
The embodiment is based on Au doped In2O3The structure schematic diagram of the nano-sphere xanthate gas sensitive element is shown in fig. 3, and the nano-sphere xanthate gas sensitive element comprises a ceramic tube 1, a gas sensitive coating 2, a heating resistance wire 3, a gold film 4, a platinum lead 5 and a hexagonal base 6, wherein the gold film 4 covers two ends of the ceramic tube 1 to form a ceramic tube electrode, the gas sensitive coating 2 is uniformly coated on the surfaces of the whole ceramic tube 1 and the gold film 4, and the heating resistance wire 3 transversely penetrates through the ceramic tube 1 and is welded on the heating electrode of the hexagonal base 6; one end of a platinum lead 4 is welded on the surface of the gold film 4, and the other end is welded on four measuring electrodes of the hexagonal base 6 to prepare In based on Au doping2O3A nano-sphere xanthate gas sensor. The gas-sensitive coating 2 is prepared by doping Au with In2O3Nanospheres of Au doped with In2O3The nanospheres are uniform in appearance and good in dispersity, and the diameter of the nanospheres is 75-125 nm. The Au is doped with In2O3The preparation process of the nanosphere comprises the following steps:
adding 1mmol of indium nitrate, 2mmol of citric acid monohydrate and 1.5mmol of urea into a mixed solution of 15ml of deionized water and 15ml of ethylene glycol in sequence, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolved.
② slowly adding 3ml of chloroauric acid solution (4.256g/L) into the solution obtained in the step (I) while stirring.
And thirdly, transferring the solution obtained in the step II to a polytetrafluoroethylene hydrothermal reaction kettle, and then placing the kettle in an oven to react for 8 hours at the temperature of 180 ℃.
After the reaction is finished, after the hydrothermal reaction kettle is naturally cooled to room temperature, washing the product obtained by the reaction for at least 2 times by using deionized water and ethanol to remove impurity ions in the product.
Fifthly, drying the cleaned product In a vacuum drying oven for 12 hours at the temperature of 30 ℃, and then carrying out heat treatment In a tubular furnace for 4 hours at the temperature of 400 ℃ to obtain Au-doped In2O3Nanospheres.
The obtained Au-doped In2O3The nanosphere has a hexagonal phase crystal structure and good crystallinity. The nanosphere has a diameter of 75-125 nm, a rough and porous surface and is composed of In2O3Nanoparticles are composed ofHas good dispersibility.
In doping based on Au2O3The preparation method of the xanthate gas sensor of the nanosphere comprises the following steps:
(ii) 0.01g of the Au was doped with In2O3Dispersing 10mL of nanospheres into absolute ethyl alcohol, grinding in an agate mortar for 10min in a fluid environment with ethyl alcohol, and mixing into pasty slurry to obtain gas-sensitive slurry.
Uniformly coating the gas-sensitive slurry on the surface of an electrode element to prepare a gas-sensitive coating, wherein the coating method comprises the step of dipping a crochet pen with Au-doped In2O3And (3) uniformly coating the nanosphere slurry on the electrode element so that the surface of the electrode element is completely covered and the thickness of the electrode element is uniform.
Thirdly, welding the prepared electrode on a hexagonal base, and aging the electrode on an aging table of a gas sensitive element for 12-24 hours at 300 ℃ to obtain the In doped based on Au2O3A nano-sphere xanthate gas sensor.
Through detection, the gas sensor prepared by the embodiment has good gas-sensitive property to xanthate gas at the working temperature of 200-325 ℃.
Example 4
In doping based on Au as described In this example2O3The structure schematic diagram of the nano-sphere xanthate gas sensitive element is shown in fig. 3, and the nano-sphere xanthate gas sensitive element comprises a ceramic tube 1, a gas sensitive coating 2, a heating resistance wire 3, a gold film 4, a platinum lead 5 and a hexagonal base 6, wherein the gold film 4 covers two ends of the ceramic tube 1 to form a ceramic tube electrode, the gas sensitive coating 2 is uniformly coated on the surfaces of the whole ceramic tube 1 and the gold film 4, and the heating resistance wire 3 transversely penetrates through the ceramic tube 1 and is welded on the heating electrode of the hexagonal base 6; one end of a platinum lead 4 is welded on the surface of the gold film 4, and the other end is welded on four measuring electrodes of the hexagonal base 6 to prepare In based on Au doping2O3A nano-sphere xanthate gas sensor. The gas-sensitive coating 2 is prepared by doping Au with In2O3Nanospheres of Au doped with In2O3The nanospheres are uniform in appearance and good in dispersity, and the diameter of the nanospheres is 75-125 nm. The Au dopingHetero In2O3The preparation process of the nanosphere comprises the following steps:
adding 1mmol of indium nitrate, 2mmol of citric acid monohydrate and 1.5mmol of urea into a mixed solution of 15ml of deionized water and 15ml of ethylene glycol in sequence, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolved.
② slowly adding 3ml of chloroauric acid solution (4.256g/L) into the solution obtained in the step (I) while stirring.
And thirdly, transferring the solution obtained in the step two to a polytetrafluoroethylene hydrothermal reaction kettle, and then placing the kettle in an oven for 12 hours at the temperature of 160 ℃.
After the reaction is finished, after the hydrothermal reaction kettle is naturally cooled to room temperature, washing the product obtained by the reaction for at least 2 times by using deionized water and ethanol to remove impurity ions in the product.
Fifthly, drying the cleaned product In a vacuum drying oven for 12 hours at the temperature of 30 ℃, and then carrying out heat treatment In a tubular furnace for 4 hours at the temperature of 300 ℃ to obtain Au-doped In2O3Nanospheres.
The obtained Au-doped In2O3The nanosphere has a hexagonal phase crystal structure and good crystallinity. The nanosphere has a diameter of 75-125 nm, a rough and porous surface and is composed of In2O3The nano particles are formed, and the dispersity is better.
In doping based on Au2O3The preparation method of the xanthate gas sensor of the nanosphere comprises the following steps:
(ii) 0.01g of the Au was doped with In2O3Dispersing the nanospheres into 10mL of absolute ethyl alcohol, grinding in an agate mortar for 10min in a fluid environment with ethyl alcohol, and mixing into pasty slurry to obtain gas-sensitive slurry.
Uniformly coating the gas-sensitive slurry on the surface of an electrode element to prepare a gas-sensitive coating, wherein the coating method comprises the step of dipping a crochet pen with Au-doped In2O3And (3) uniformly coating the nanosphere slurry on the electrode element so that the surface of the electrode element is completely covered and the thickness of the electrode element is uniform.
Welding the prepared electrode to a hexagonal baseAging the alloy on an aging table of a gas sensitive element for 12-24 hours at 300 ℃ to obtain the In based on Au doping2O3A nano-sphere xanthate gas sensor.
Through detection, the gas sensor prepared by the embodiment has good gas-sensitive property to xanthate gas at the working temperature of 200-325 ℃.

Claims (8)

1. In doping based on Au2O3The gas-sensitive element of the xanthate gas of the nanosphere is characterized In that the gas-sensitive element mainly comprises an electrode element and Au doped In uniformly coated on the electrode element2O3Composition of nanospheres, said Au being doped with In2O3The nanospheres are hexagonal crystal structures, have diameters of 75-125 nm, are rough and porous in surface, uniform in appearance and good in dispersity;
the Au is doped with In2O3The nanospheres are prepared as follows:
sequentially adding indium nitrate, citric acid monohydrate and urea into a mixed solution of deionized water and ethylene glycol according to a molar ratio of 1:2:1.5, wherein the volume ratio of the deionized water to the ethylene glycol is 1:1, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolved;
slowly adding a certain amount of chloroauric acid solution into the solution obtained in the step (i) in the stirring process, wherein the molar ratio of chloroauric acid to indium nitrate is 1: 100-5: 100;
transferring the solution obtained in the step II to a hydrothermal reaction kettle, and then placing the hydrothermal reaction kettle in an oven to react for 6-24 hours at the temperature of 120-180 ℃;
fourthly, after the reaction is finished, after the hydrothermal reaction kettle is cooled to room temperature, washing and drying a product obtained by the reaction, and then carrying out heat treatment In a tubular furnace at the temperature of 200-400 ℃ for 2-5 h to obtain Au-doped In2O3Nanospheres.
2. The gas sensor of claim 1, wherein the electrode element is a ceramic electrode.
3. The gas sensor of claim 1, wherein the electrode element is in the shape of a tubular electrode or a planar electrode.
4. The gas sensor according to claim 1, wherein the washing and drying in the step (iv) comprises washing the precipitated product with deionized water and absolute ethanol at least 2 times, respectively, and drying in a drying oven at 30-80 ℃ for 12-48 h.
5. The method for producing a gas sensor according to claim 1, comprising the steps of:
sequentially adding indium nitrate, citric acid monohydrate and urea into a mixed solution of deionized water and ethylene glycol according to a molar ratio of 1:2:1.5, wherein the volume ratio of the deionized water to the ethylene glycol is 1:1, and stirring at room temperature until the indium nitrate, the citric acid monohydrate and the urea are completely dissolved; slowly adding a chloroauric acid solution with the molar ratio of 1: 100-5: 100 to indium nitrate into the solution during stirring; transferring the obtained solution to a hydrothermal reaction kettle, and then placing the hydrothermal reaction kettle in an oven to react for 6-24 hours at the temperature of 120-180 ℃; after the reaction is finished, after the hydrothermal reaction kettle is cooled to room temperature, washing and drying a product obtained by the reaction, and carrying out heat treatment In a tubular furnace at the temperature of 200-400 ℃ for 2-5 h to obtain Au-doped In2O3Nanospheres;
② doping In with Au obtained In the step I2O3Dispersing the nanospheres into absolute ethyl alcohol, grinding for 10min by a wet method, and mixing into pasty slurry to obtain gas-sensitive slurry;
uniformly coating the gas-sensitive slurry obtained in the step two on the surface of an electrode element;
fourthly, coating Au In the third step to dope In2O3Connecting the electrode element of the nanosphere to a hexagonal base, then installing the electrode element on an aging table of the gas sensitive element, and aging the electrode element for 12-24 hours at 300 ℃ to obtain the In doped Au2O3A nano-sphere xanthate gas sensor.
6. The preparation method according to claim 5, wherein the washing and drying processes in the step (i) are washing the precipitated product with deionized water and absolute ethanol for at least 2 times respectively, and then drying the product in a drying oven at 30-80 ℃ for 12-48 h.
7. The preparation method according to claim 5, wherein the wet grinding In the step (II) is carried out by doping Au dispersed In ethanol with In2O3The nanospheres were placed in an agate mortar and ground into a paste slurry in a fluid environment with ethanol.
8. The method according to claim 5, wherein the slurry coating method In step (iii) is to dip a pen for picking In doped Au2O3And (3) uniformly coating the nanosphere slurry on the electrode element so that the surface of the electrode element is completely covered and the thickness of the electrode element is uniform.
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