阅读说明：本技术 一种氧化铜和四氧化三钴异质结构纳米线复合敏感材料、乙二醇传感器及制备方法 (A kind of copper oxide and cobaltosic oxide heterogeneous structural nano line composite sensitive material, ethylene glycol sensor and preparation method ) 是由 张璐 苏晨 韩鹏涛 顾陇 刘金妹 于 2019-09-27 设计创作，主要内容包括：一种氧化铜和四氧化三钴异质结构纳米线复合敏感材料、乙二醇传感器及制备方法,CuO/Co<Sub>3</Sub>O<Sub>4</Sub>异质结构纳米线呈核壳式结构,其中,CuO作为核,其外层包裹的Co<Sub>3</Sub>O<Sub>4</Sub>纳米片作为壳。本发明在敏感材料的制备过程中,采用在空气气氛下高温退火处理水热法合成的纳米线前驱体来制备CuO/Co<Sub>3</Sub>O<Sub>4</Sub>纳米线。整个合成过程简单、高效,适于规模化生产。多级核壳结构为气体反应提供了更多活性位点。而且p-p型异质结的存在,进一步促进了复合材料对乙二醇的响应。此气体传感器具有优异的灵敏度、超快的响应速度、出色的选择性、可靠的长期稳定性和较低的理论检测极限,适用于高灵敏度地检测乙二醇气体。(A kind of copper oxide and cobaltosic oxide heterogeneous structural nano line composite sensitive material, ethylene glycol sensor and preparation method, CuO/Co 3 O 4 Heterogeneous structural nano line is in core shell structure, wherein CuO is as core, the Co of outer layer covers 3 O 4 Nanometer sheet is as shell.The present invention prepares CuO/Co using the nanowire precursor of the synthesis of the high temperature anneal hydro-thermal method in air atmosphere in the preparation process of sensitive material 3 O 4 Nano wire.Entire synthesis process is simple, efficient, is suitable for large-scale production.Multistage core-shell structure provides more active sites for gas reaction.And the presence of p-p type hetero-junctions, further promote response of the composite material to ethylene glycol.This gas sensor has excellent sensitivity, ultrafast response speed, outstanding selectivity, reliable long-time stability and lower theoretical detection limit, is suitable for detecting ethylene glycol gas in high sensitivity.)

1. a kind of copper oxide and cobaltosic oxide heterogeneous structural nano line composite sensitive material, it is characterised in that: the sensitive material With CuO/Co₃O₄Heterogeneous structural nano line, the CuO/Co₃O₄Heterogeneous structural nano line is in core shell structure, wherein CuO As core, the Co of outer layer covers₃O₄Nanometer sheet is greater than 10 μm as shell, the length of single nano wire, the diameter of single nano wire For 600nm-800nm, Co₃O₄The thickness of nanometer sheet is less than 6nm.

2. the preparation side of a kind of copper oxide as described in claim 1 and cobaltosic oxide heterogeneous structural nano line composite sensitive material Method, which comprises the following steps:

(1) CuO/Co is prepared₃O₄Nanowire precursor；

1. ethyl alcohol is mixed with deionized water, and Cu nano wire being added into this solution, ultrasound makes Cu nano wire be uniformly dispersed, then It is separately added into cabaltous nitrate hexahydrate, ammonium fluoride and urea into above-mentioned solution, continues to stir evenly, obtains mixed solution；

2. 1. solution that step is obtained 6~8h of hydro-thermal reaction at 80 DEG C~100 DEG C, after cooled to room temperature, by gained Brownish black precipitate eccentric cleaning, be dried later, obtain CuO/Co₃O₄Nanowire precursor；

(2) CuO/Co is prepared₃O₄Nano wire composite sensitive material；

By CuO/Co obtained₃O₄Nanowire precursor is made annealing treatment, and CuO/Co is obtained₃O₄Nano wire.

3. preparation method according to claim 2, it is characterised in that: the volume ratio of the ethyl alcohol and deionized water is 1: 1；The diameter of the Cu nano wire is less than 250nm, and length is greater than 10 μm.

4. preparation method according to claim 2, it is characterised in that: the cabaltous nitrate hexahydrate is molten in mixing after being added Concentration in liquid is 0.005M~0.02M, after the ammonium fluoride is added concentration in mixed solution be 0.0025M~ 0.02M, the concentration after the urea addition in mixed solution is 0.0125M~0.05M.

5. preparation method according to claim 2, it is characterised in that: the solvent of eccentric cleaning is selected from deionized water, ethyl alcohol One of or deionized water and ethanol composition mixed solvent；The speed of the centrifugation is 5000rpm~8000rpm, described The time of centrifugation is 5min~10min, and the temperature of the drying is 50 DEG C~80 DEG C, and drying time is 5h~12h.

6. preparation method according to claim 2, it is characterised in that: the annealing is placed in Muffle furnace and carries out, Calcination temperature is 350 DEG C~550 DEG C, and calcination time is 2h~3h, and heating rate is 2 DEG C/min~10 DEG C/min.

7. a kind of ethylene glycol sensor, it is characterised in that: included there are two annular gold electrode separate including outer surface Al₂O₃Ceramic tube, Al₂O₃Ceramic tube inside is equipped with nickel-cadmium coil, annular gold electrode and Al₂O₃Ceramic tube outer surface uniformly applies It is covered with copper oxide and cobaltosic oxide heterogeneous structural nano line composite sensitive material as described in claim 1.

8. a kind of preparation method of ethylene glycol sensor as claimed in claim 7, which comprises the following steps:

1. by CuO/Co₃O₄Heterogeneous structural nano line composite sensitive material powder with dehydrated alcohol is that 1:10 is mixed in mass ratio, and So that it is uniformly dispersed, above-mentioned dispersant liquid drop is then taken to come with the Al of two annular gold electrodes separate in outer surface₂O₃Ceramics Pipe surface, until ethanol evaporation forms the sensitive material film of all standing annular gold electrode；

2. nickel-cadmium coil is passed through Al₂O₃Ceramic tube inside is as heater strip；Finally, by above-mentioned device according to general indirect heat Formula gas sensor is welded and is encapsulated, and ethylene glycol sensor is then obtained.

9. preparation method according to claim 8, it is characterised in that: the step 1. in by CuO/Co₃O₄Heterojunction structure Nano wire composite sensitive material powder and dehydrated alcohol are uniformly dispersed by ultrasonic vibration, then are taken on 6 μ of μ L~10 L with liquid-transfering gun It states dispersant liquid drop and comes with the Al of two annular gold electrodes separate in outer surface₂O₃Ceramic pipe surface, makes Al₂O₃Ceramic tube Horizontal uniform rotation, until ethanol evaporation forms the sensitive material film of all standing annular gold electrode.

Technical field

The present invention relates to gas sensor domains, and in particular to a kind of copper oxide and cobaltosic oxide heterogeneous structural nano line Composite sensitive material, ethylene glycol sensor and preparation method realize detection quick to ethylene glycol gas, sensitive, repeatable.

Background technique

In the industrial production, ethylene glycol is widely used in organic solvent, antifreezing agent and conjunction as a kind of important source material In terylene.However, ethylene glycol contains hydroxyl, when working at 80 DEG C~90 DEG C for a long time, ethylene glycol can first be oxidized to second Alkyd, then it is oxidized to oxalic acid.And oxalic acid and its by-product can first influence the central nervous system of human body, cause to have difficulty in breathing, Cause pulmonary edema etc., if do not used appropriate ways to treat, absorbing excessive ethylene glycol will lead to death.Therefore, high-performance is manufactured Ethylene glycol gas sensor for environmental monitoring and human health protection have important and urgent meaning.

In the gas sensor of numerous kinds, the resistor-type gas sensor based on metal oxide semiconductor has system Standby at low cost, Monitoring lower-cut is low, and response, the advantages that resume speed is fast, are the advantageous candidates for realizing ethylene glycol gas real-time detection Device.

Wherein, CuO and Co₃O₄As typical p-type oxide semiconductor sensitive material, there is high catalytic activity, Neng Gou It works at lower temperature, is had been a great concern in monitoring poisonous gas field.However, it is many based on simple CuO and Co₃O₄Gas sensitivity it is lower, selectivity it is bad.Therefore, it is necessary to by CuO and Co₃O₄It is compound to construct hetero-junctions, By the synergistic effect between both ingredients, the sensing capabilities of composite material are further promoted.

Summary of the invention

It is an object of the invention to be directed to, above-mentioned gas sensitivity in the prior art is lower, selectivity is bad is asked Topic provides a kind of copper oxide and cobaltosic oxide heterogeneous structural nano line composite sensitive material, ethylene glycol sensor and preparation side Method, obtained core-shell structure CuO/Co₃O₄Nano wire, multilevel structure makes sensitive material have bigger specific surface area, for gas Body molecule provides more adsorption sites, and it is highly sensitive, quick that the gas sensor of preparation helps to realize ethylene glycol gas Detection.

To achieve the goals above, the present invention has the following technical solution:

A kind of CuO/Co₃O₄Heterogeneous structural nano line composite sensitive material, the CuO/Co having₃O₄Heterogeneous structural nano line In core shell structure, wherein CuO is as core, the Co of outer layer covers₃O₄Nanometer sheet is greater than as shell, the length of single nano wire 10 μm, the diameter of single nano wire is 600nm-800nm, Co₃O₄The thickness of nanometer sheet is less than 6nm.

CuO/Co of the present invention₃O₄The preparation method of heterogeneous structural nano line composite sensitive material, comprising the following steps:

(1) CuO/Co is prepared₃O₄Nanowire precursor；

1. ethyl alcohol is mixed with deionized water, and Cu nano wire is added into this solution, ultrasound keeps the dispersion of Cu nano wire equal It is even, then cabaltous nitrate hexahydrate, ammonium fluoride and urea are separately added into above-mentioned solution, continue to stir evenly, obtains mixed solution；

2. 1. solution that step is obtained 6~8h of hydro-thermal reaction at 80 DEG C~100 DEG C will after cooled to room temperature Resulting brownish black precipitates eccentric cleaning, is dried later, obtains CuO/Co₃O₄Nanowire precursor；

(2) CuO/Co is prepared₃O₄Nano wire composite sensitive material；

By CuO/Co obtained₃O₄Nanowire precursor is made annealing treatment, and CuO/Co is obtained₃O₄Nano wire.

Preferably, in one embodiment of preparation method of the present invention, in the step (1), ethyl alcohol and deionized water Volume ratio be 1:1；The diameter of the Cu nano wire is less than 250nm, and length is greater than 10 μm.

Preferably, the cabaltous nitrate hexahydrate is mixing after being added in one embodiment of preparation method of the present invention Concentration in solution is 0.005M~0.02M, after the ammonium fluoride is added concentration in mixed solution be 0.0025M~ 0.02M, the concentration after the urea addition in mixed solution is 0.0125M~0.05M.

Preferably, the solvent of eccentric cleaning is selected from deionized water, ethyl alcohol in one embodiment of preparation method of the present invention One of or deionized water and ethanol composition mixed solvent；The speed of the centrifugation is 5000rpm~8000rpm, described The time of centrifugation is 5min~10min, and the temperature of the drying is 50 DEG C~80 DEG C, and drying time is 5h~12h.

Preferably, the annealing is placed in Muffle furnace and carries out in one embodiment of preparation method of the present invention, Calcination temperature is 350 DEG C~550 DEG C, and calcination time is 2h~3h, and heating rate is 2 DEG C/min~10 DEG C/min.

The present invention gives a kind of ethylene glycol sensor, including outer surface is included that there are two annular gold electrodes separate Al₂O₃Ceramic tube, Al₂O₃Ceramic tube inside is equipped with nickel-cadmium coil, annular gold electrode and Al₂O₃Ceramic tube outer surface is uniform Coated with above-mentioned copper oxide and cobaltosic oxide heterogeneous structural nano line composite sensitive material.

The present invention gives a kind of preparation method of ethylene glycol sensor, comprising the following steps:

1. by CuO/Co₃O₄Heterogeneous structural nano line composite sensitive material powder and dehydrated alcohol are mixed for 1:10 in mass ratio It closes, and it is made to be uniformly dispersed, above-mentioned dispersant liquid drop is then taken to come with two annular gold electrodes separate in outer surface Al₂O₃Ceramic pipe surface, until ethanol evaporation forms the sensitive material film of all standing annular gold electrode；

2. nickel-cadmium coil is passed through Al₂O₃Ceramic tube inside is as heater strip；Finally, by above-mentioned device according to general Heater-type gas sensor is welded and is encapsulated, and ethylene glycol sensor is then obtained.

Preferably, in the preparation method of ethylene glycol sensor of the present invention, the step 1. in by CuO/Co₃O₄It is heterogeneous Structure nanometer wire composite sensitive material powder and dehydrated alcohol are uniformly dispersed by ultrasonic vibration, then take 6 μ of μ L~10 with liquid-transfering gun The above-mentioned dispersant liquid drop of L comes with the Al of two annular gold electrodes separate in outer surface₂O₃Ceramic pipe surface, makes Al₂O₃Ceramics The horizontal uniform rotation of pipe, until ethanol evaporation forms the sensitive material film of all standing annular gold electrode.

Compared to the prior art, composite sensitive material of the present invention is with following the utility model has the advantages that possessed CuO/Co₃O₄ Heterogeneous structural nano line is in core shell structure, can effectively promote the specific surface area of sensitive material, the Co of outer layer covers₃O₄Nanometer Piece thickness is less than 6nm, this largely increases the active site that sensitive material is reacted under test gas.

Compared to the prior art, the preparation method of composite sensitive material of the present invention is with following the utility model has the advantages that utilizing water Thermal method combination the high temperature anneal prepares the nuclear shell structure nano line sensitive material, and synthetic method is simple.CuO,Co₃O₄Both Typical P-type material has the advantages that catalytic activity is high, detection of gas temperature is low.The present invention is by by both p-type semiconductors It combines to construct p-p hetero-junctions, has benefited from the synergistic effect of two kinds of materials, sensitive material has greatly the sensitivity of ethylene glycol Width is promoted, and has cracking response speed and stable test characteristic, is had in terms of ethylene glycol content in detection environment wide Application prospect.

Compared to the prior art, ethylene glycol sensor of the invention, selects commercially available Al₂O₃Ceramic pipe type electrode, device technology Simply, small in size, it is suitable for producing in enormous quantities.This gas sensor has excellent sensitivity, ultrafast response speed, outstanding Selectivity, reliable long-time stability and low theoretical detection limit, the high sensitivity detection suitable for ethylene glycol gas.

Detailed description of the invention

Fig. 1 a is CuO/Co in embodiment 2₃O₄The electron scanning micrograph of nano wire；

Fig. 1 b and Fig. 1 c are CuO/Co in embodiment 2₃O₄The transmission electron microscope photo of nano wire；

Fig. 2 is CuO/Co in embodiment 2₃O₄The X-ray diffractogram of nano wire hetero structure compound；

Fig. 3 is the structural schematic diagram of heater-type ethylene glycol sensor；

Fig. 4 is for the sensor based on embodiment 1, embodiment 2 and embodiment 3 to 100ppm second two at a temperature of different operating The response curve of alcohol；

Fig. 5 is for the sensor based on embodiment 2 to the response recovery curve of various concentration ethylene glycol at 130 DEG C；

Fig. 6 is the sensor based on embodiment 2 in 130 DEG C and ethyl alcohol, formaldehyde, methanol, ammonia, third under 100ppm concentration Ketone, normal propyl alcohol, ethylene glycol gas-selectively can scheme；

Fig. 7 is the sensor based on embodiment 2 under 130 DEG C of operating temperature, detects 100ppm concentration ethylene glycol gas Performance figure steady in a long-term.

Specific embodiment

With reference to the accompanying drawing and specific embodiment is described in further detail technical solution of the present invention.These are provided The purpose of explanation, which is only that, helps explain the present invention, is not the covering scope for limiting claim of the invention.

The present invention provides a kind of CuO/Co₃O₄Heterogeneous structural nano line, CuO/Co₃O₄Heterogeneous structural nano line is in nucleocapsid Structure, wherein CuO is " core ", the Co of outer layer covers₃O₄Nanometer sheet is " shell ".CuO/Co₃O₄The length of heterogeneous structural nano line is big In 10 μm, diameter is about 600nm, Co₃O₄Nanometer sheet thickness is less than 6nm.The present invention synthesizes Cu nano wire first, passes through water later Thermal method coats Co in Cu nanowire surface₃O₄Nanometer sheet obtains CuO/Co₃O₄Nanowire precursor；Then high in air atmosphere Temperature annealing, by above-mentioned CuO/Co₃O₄Nanowire precursor oxidation finally obtains CuO/Co₃O₄Nano wire.

The present invention is based on CuO/Co₃O₄The ethylene glycol sensor of heterogeneous structural nano line, by outer surface, included there are two that The Al of this discrete annular gold electrode₂O₃Ceramic tube is uniformly coated on annular gold electrode and Al₂O₃The sensitivity of ceramic tube outer surface Material film, Al₂O₃The nickel-cadmium coil of ceramic tube inside forms, and is prepared by following steps:

(1)CuO/Co₃O₄The preparation of nanowire precursor:

1. 20mL ethyl alcohol is mixed with 20mL deionized water, and the Cu nano wire of 20mg is added into this solution, ultrasound makes Cu nano wire is uniformly dispersed.0.4mmol cabaltous nitrate hexahydrate, 0.2mmol~0.4mmol are separately added into above-mentioned solution later Ammonium fluoride and 1mmol urea.Continue to stir 20min, is uniformly mixed the above solution.

2. above-mentioned reaction solution is reacted 8h at 90 DEG C.

3. to after reaction, by the mixed of a kind of in grey black precipitating deionized water, ethyl alcohol or deionized water and ethyl alcohol Liquid eccentric cleaning is closed, dries 5~12h in an oven later, drying temperature is 50~80 DEG C, obtains CuO/Co₃O₄Nano wire forerunner Body.

(2)CuO/Co₃O₄The preparation of nano wire composite sensitive material:

By CuO/Co₃O₄Nanowire precursor is placed in Muffle furnace and is made annealing treatment.It 350~550 DEG C of annealing temperature, moves back The fiery time is 2~3h, and heating rate is 2~10 DEG C/min.Subsequent cooled to room temperature is to get arriving CuO/Co₃O₄Nano wire.

(3) production of ethylene glycol gas sensor:

1. by CuO/Co₃O₄Nanowire composite powder is mixed with dehydrated alcohol 1:10 in mass ratio, and ultrasound makes its dispersion Uniformly, then take 6~10 above-mentioned dispersant liquid drops of μ L included there are two annular gold electrode in commercially available outer surface with liquid-transfering gun Al₂O₃Ceramic pipe surface makes the horizontal uniform rotation of ceramic tube, until ethanol evaporation forms the sensitive material of all standing annular gold electrode Expect film.

2. nickel-cadmium coil is passed through Al₂O₃Ceramic tube inside is as heater strip, finally by above-mentioned device according to general side Hot type gas sensor is welded and is encapsulated, to obtain CuO/Co₃O₄Nanowire composite ethylene glycol sensor.