CN108872324B - Xylene gas sensor based on nano composite sensitive material and preparation method thereof - Google Patents
Xylene gas sensor based on nano composite sensitive material and preparation method thereof Download PDFInfo
- Publication number
- CN108872324B CN108872324B CN201810464724.XA CN201810464724A CN108872324B CN 108872324 B CN108872324 B CN 108872324B CN 201810464724 A CN201810464724 A CN 201810464724A CN 108872324 B CN108872324 B CN 108872324B
- Authority
- CN
- China
- Prior art keywords
- sensitive material
- nio
- nicr
- xylene
- ceramic tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
NiO/NiCr-based2O4A xylene gas sensor of nano composite sensitive material and a preparation method thereof belong to the technical field of semiconductor oxide gas sensors. Which is commercially available Al with 2 ring-shaped gold electrodes2O3Insulating ceramic tube, coatingIn the annular gold electrode and Al2O3Semiconductor sensitive material on insulating ceramic tube, and through Al2O3A nichrome coil of the insulating ceramic tube; the semiconductor sensitive material is NiO/NiCr2O4A nano composite sensitive material. The method utilizes a method for forming a semiconductor heterogeneous P-P junction to modify the P-type NiO semiconductor sensitive material, regulates and controls a carrier transmission channel, improves the synergistic catalytic activity, improves the selectivity and realizes the great leap of the gas-sensitive property. The sensor showed excellent selectivity to xylene (S)Xylene/SEthanol11.8), ultrahigh sensitivity (66.2-100 ppm) and ultralow detection lower limit (50ppb), and has wide application prospect in selectively detecting trace xylene pollutants in a microenvironment.
Description
Technical Field
The invention belongs to the technical field of semiconductor oxide gas sensors, and particularly relates to a NiO/NiCr-based sensor2O4A xylene gas sensor which is made of nano composite sensitive material and can realize high selectivity and low concentration detection and a preparation method thereof.
Background
With the rapid development of society, people make obvious progress in various fields such as industry, energy, traffic and the like, and bring serious environmental pollution and other problems which cannot be avoided. The air quality is seriously affected by the waste gas discharged by industrial production, automobile tail gas and the like, and various extreme weathers are frequent. Besides, the air pollution of the microenvironment space cannot be ignored, which is mainly characterized in that volatile organic pollutants volatilized from home decoration coatings, furniture paints, automobile spray paints, leather products and the like, such as VOCs (volatile organic compounds) gases such as toluene, formaldehyde, xylene and the like, can directly or indirectly damage the human body. Therefore, it is important to enhance the monitoring and evaluation of air quality and the detection of pollutants in the air, which actually affects people's health and national development. Among various gas sensors, a resistive gas sensor using a semiconductor oxide as a sensitive material is one of the most widely used gas sensors at present and is a research hotspot in the field of gas sensing because of the advantages of high sensitivity, low detection lower limit, fast response and recovery speed, simple manufacturing method, low cost and the like. In practical applications, it is not difficult to find that it is very important to realize specific selective detection of a certain gas, and certainly, excellent selectivity is always a performance index which is realized in the field of gas sensor research, and is a challenge to be solved in the field of research.
Research on the sensing performance of NiO nano sensitive materials shows that although the sensitivity is relatively low compared with certain N-type metal oxide semiconductors, NiO has excellent catalytic oxidation activity on the oxidation of Volatile Organic Compounds (VOC) and has better moisture resistance, and the characteristics are favorable for constructing gas sensors sensitive to VOC gases. The modification means for semiconductor sensitive materials mainly include the following three types: noble metal loading, aliovalent metal ion doping, and composite formation, wherein composite formation is an effective modification method. A large number of research results show that homojunctions or heterojunctions formed in the composite material have a good regulation and control effect on carrier concentration and a conductive channel, and the gas-sensitive property of the sensitive material can be effectively improved. Moreover, the nanoscale heterostructure formed in the two well-mixed semiconductor composite materials further promotes the enhancement of gas-sensitive characteristics.
In this patentThe NiO nano sensitive material is modified and sensitized by adopting a method for forming a nano heterogeneous semiconductor P-P junction, namely, the uniformly mixed NiO/NiCr is synthesized by adopting a hydrothermal method2O4The nanometer composite material improves the sensitivity of the sensitive material to the xylene gas through the regulation and control effect of a plurality of formed nanometer heterogeneous P-P junctions, and reduces the lower limit of detection. Further, NiO/NiCr2O4The synergistic catalytic activity remarkably enhanced in the nanocomposite promotes the sensitive reaction between the material and the xylene gas, thereby improving the selectivity of the sensitive material to the gas.
Disclosure of Invention
The invention aims to provide a NiO/NiCr-based NiCr2O4A xylene gas sensor of nano composite sensitive material and a preparation method thereof.
Using NiO/NiCr2O4The semiconductor nano composite structure is used as a sensitive material, on one hand, the NiO nano sensitive material has stronger oxidability and better catalytic oxidation activity to various VOC gases, and can cause more oxygen molecules to participate in the reaction; moreover, by carrying out semiconductor composite modification and sensitization treatment on the NiO material, a plurality of nano-scale heterogeneous P-P junctions can be formed at the interface of the two materials, and the NiO/NiCr is greatly improved2O4The specific surface area and the porosity of the nano composite structure obtain smaller particle size, so that the oxygen adsorption capacity is enhanced, and the gas-sensitive characteristic is promoted to be improved; in addition, the nanoscale P-P heterojunction formed in the composite material can effectively regulate and control carrier concentration and a conductive channel, remarkably improves the sensitivity (66.2-100 ppm) of P-xylene gas, and obtains a lower detection lower limit (50 ppb). In addition, due to uniform nano-scale contact between two P-type semiconductor materials with catalytic activity, the synthesized NiO/NiCr2O4The synergistic catalytic activity of the composite material to the dimethylbenzene gas is obviously enhanced, and the selectivity of the composite sensitive material to the dimethylbenzene gas is obviously improved. The sensor with the tubular structure is simple in manufacturing process, small in size and beneficial to industrial mass production, and therefore has important application value.
The NiO/NiCr-based NiCr/NiCr-based NiO/NiCr-based NiCr composite material is provided by the invention2O4The xylene gas sensor of nano composite sensitive material is formed from Al whose external surface is equipped with two parallel, ring-shaped and mutually-separated gold electrodes2O3Ceramic tube substrate coated with Al2O3Sensitive material on the outer surface of the ceramic tube and the gold electrode, Al2O3A nichrome coil in the ceramic tube; the method is characterized in that: the sensitive material is NiO/NiCr2O4The nano composite sensitive material is prepared by the following steps,
(1) 0.05-0.35 g of CrCl3·6H2O、0.35～0.65g NiCl2·6H2Adding O and 0.21-0.41 g of HMT (hexamethylenetetramine) into 20-40 mL of deionized water, stirring until the O and the HMT are completely dissolved, and then adding 1-4 mL of ethanolamine into the deionized water;
(2) carrying out hydrothermal reaction on the solution at 160-200 ℃ for 6-10 hours, taking out, naturally cooling to room temperature, carrying out multiple centrifugal cleaning on the generated precipitate by using deionized water and ethanol, drying at room temperature, and finally calcining at 400-600 ℃ for 2-4 hours to obtain NiO/NiCr2O4Nano composite sensitive material powder.
The NiO/NiCr-based NiCr/NiCr-based NiO/NiCr-based NiCr composite material is provided by the invention2O4The preparation method of the xylene gas sensor of the nano composite sensitive material comprises the following steps:
(1) taking 8-20 mg of NiO/NiCr2O4Mixing the nano composite sensitive material powder with 40-100 mu L of deionized water, grinding to form pasty slurry, dipping a small amount of slurry, and uniformly coating the slurry on Al with two parallel, annular and mutually separated gold electrodes on the outer surface2O3Forming a sensitive material film on the surface of the ceramic tube substrate, and enabling the sensitive material to completely cover the annular gold electrode, wherein the thickness of the sensitive material film is 40-50 mu m;
(2) baking for 20-40 minutes under an infrared lamp, and drying the sensitive material, and then adding Al2O3Calcining the ceramic tube at 400-600 ℃ for 2-4 hours; then enabling the nichrome coil with the resistance value of 30-40 omega to penetrate through Al2O3The ceramic tube is internally used as a heating wire, and finally welding and packaging are carried out according to an indirectly heated gas sensitive element, so that NiO/NiCr-based gas sensor is obtained2O4Xylene gas sensor of nanometer composite sensitive material; wherein, Al2O3The ceramic tube has a length of 4-4.5 mm, an outer diameter of 1.2-1.5 mm, an inner diameter of 0.8-1.0 mm, a width of 0.15-0.3 mm and a spacing of 0.4-0.6 mm.
NiO/NiCr-based material prepared by the invention2O4The xylene gas sensor of the nano composite sensitive material has the following advantages:
1. the NiO/NiCr is successfully prepared by a one-step simple hydrothermal method2O4The nano composite sensitive material has simple synthetic method and low cost;
2. the method has the advantages that the heterogeneous semiconductor composite modification and sensitization treatment is carried out on the NiO sensitive material, so that the gas sensitivity of the NiO-based gas sensor to xylene is remarkably improved, the sensitivity is greatly improved (66.2-100 ppm), the lower detection limit of xylene gas is remarkably reduced (1.2-50 ppb), and the xylene selectivity (S) relative to interference gas is excellentXylene/SEthanol11.8) and good stability, it can be seen based on NiO/NiCr2O4The gas sensor of the nano composite sensitive material has wide application prospect in selectively detecting trace xylene pollutants in the environment;
3. the tube sensor is commercially available, and the device has simple process and small volume and is suitable for mass production.
Drawings
FIG. 1: (a) and (b) Cr which is not subjected to composite modification treatment2O3(comparative example 1) and NiO (comparative example 2) SEM topography of sensitive materials, (c) and (d) are NiO/NiCr in sequence2O4Global and local magnified SEM topography maps of the nanocomposite structures (example 2);
FIG. 2: (a, b) are pure phase NiO (comparative example 2) and NiO/NiCr2O4Nanocomposite structures (example 2) and Cr2O3XRD spectrum pattern of nanomaterial (comparative example 1);
FIG. 3: (a) comparative examples 1 and 2 (Cr)2O3And NiO) and example 2 (NiO/NiCr)2O4) The sensitivity curve of the middle sensor to 100ppm xylene gas under different working temperatures, (b) the sensitivity (selectivity) histogram of the three sensors to 6 kinds of 100ppm gases to be measured under the optimal working temperature (225 ℃);
FIG. 4: (a) example 2 (NiO/NiCr)2O4) Sensitivity profiles of the middle sensor at different operating temperatures for six 100ppm gases to be measured, (b) relative to interfering gases (100ppm ethanol and acetone), example 2 (NiO/NiCr)2O4) Sensitivity curves of the medium sensor to 100ppm xylene at different working temperatures;
FIG. 5: (a-c) comparative examples 1 and 2 (Cr)2O3And NiO) and example 2 (NiO/NiCr)2O4) Resistance characteristic curve of medium sensor under optimum working temperature (225 ℃) along with real-time change of xylene concentration (10-200ppm), (d) example 2 (NiO/NiCr)2O4) The characteristic curve of the resistance of the medium sensor changing along with the real-time change of the lower xylene concentration (50ppb-5ppm) when the medium sensor works at the optimal working temperature (225 ℃);
FIG. 6: (a, b) comparative example 1 and comparative example 2 (Cr)2O3And NiO) and example 2 (NiO/NiCr)2O4) The sensitivity curves in xylene gas at different concentrations (50ppb-200ppm) when three of the sensors are operated at the optimum temperature (225 ℃);
FIG. 7: example 2 (NiO/NiCr)2O4) Long-term stability curves of the resistance in air and sensitivity in 100ppm xylene gas for the medium sensor operating at the optimum operating temperature (225 ℃);
as shown in FIG. 1, synthesized Cr2O3NiO and NiO/NiCr2O4The nanostructures are assembled from a collection of nanoparticles and it is evident that NiO/NiCr2O4The particle size (8 mu m) of the nano-particles in the nano-composite material is obviously smaller than that of the un-compounded Cr2O3And NiO nanoparticles (. about.40 μm).
As shown in FIG. 2, NiO and Cr2O3The XRD spectral line of the sensitive material is respectively matched with standard NiO (73-1519) and standard Cr2O3(82-1484) match is good, no other phase heteropeaks appear, and the NiO/NiCr synthesized2O4Example 2 NiO and NiCr were clearly present in the XRD pattern of the nanocomposite structure2O4Characteristic peaks of two phases, respectively with standard NiO (73-1519) and NiCr2O4(75-1728) the matching is good, and no other phase impurity peak appears, which indicates that the composite material synthesized by the hydrothermal method is prepared from NiO and NiCr2O4The two materials are compounded.
As shown in FIG. 3a, the sensors in example 2, comparative example 1 and comparative example 2 all had an optimum operating temperature of 225 deg.C, which shows that example 2 (NiO/NiCr)2O4) The gas sensor in (1) shows the optimal gas-sensitive characteristic, and the sensitivity to 100ppm dimethylbenzene is 66.2, which is obviously higher than that of the gas sensor based on the non-composite sensitive material in the comparative example. And from FIG. 3b, it can be seen that example 2 (NiO/NiCr) is compared to the other gases2O4) The gas sensor in (3) has the highest sensitivity to xylene and shows excellent xylene selectivity.
As shown in FIG. 4a, the temperature range of 175-300 ℃ for example 2 (NiO/NiCr)2O4) The sensor in (1) selectively tests 100ppm of gas to be tested in (6), which can be seen in example 2 (NiO/NiCr)2O4) The gas sensor in (1) always shows excellent selectivity to xylene. In addition, in the interfering gas, the sensitivity of ethanol and acetone is relatively high, so taking these two gases as an example, example 2 (NiO/NiCr) was studied with respect to the interfering gas2O4) The gas sensor of (1) is selective for para-xylene. It can be seen that at the optimum operating temperature of 225 deg.C, the sensitivity ratio of xylene gas to ethanol and acetone, respectively, is SXylene/SEthanol11.8 and SXylene/SAcetone (II)The excellent selectivity of the sensor for xylene gas is further illustrated by 10.2, which allows for selective detection of xylene gas.
As shown in fig. 5, for the sensors of comparative examples 1 and 2 and example 2 exposed to xylene, the resistance of the semiconductor became large and increased stepwise with the increase in the xylene concentration, which is consistent with the gas-sensitive characteristics of the P-type oxide semiconductor, and the sensors exhibited excellent response and recovery characteristics to different concentrations of xylene. In addition, the gas sensor in the embodiment 2 has a lower detection limit, which can reach 50ppb, and can be used for detecting low-concentration xylene gas.
As shown in FIG. 6, the sensitivity of the sensors to xylene increases with the xylene concentration in comparative examples 1 and 2 and example 2, where (NiO/NiCr) in example 22O4) The sensitivity of the device increases significantly with increasing xylene concentration, significantly higher than that of the device without complex modification (Cr)2O3And NiO) the gas sensors in comparative example 1 and comparative example 2. In example 2 (NiO/NiCr)2O4) The sensitivity of the gas sensor to 200ppm xylene reaches 90, the sensitivity to 50ppb xylene is 1.2, and the gas sensor shows excellent xylene gas-sensitive performance.
As shown in FIG. 7, (NiO/NiCr) of example 2 operated at a temperature of 225 ℃ for 1 month of the continuous test2O4) The initial resistance of the sensor in air and its corresponding sensitivity curve in 100ppm xylene gas fluctuate little, showing good long term stability.
Note: in practical tests, the gas-sensitive characteristic of the sensor in the embodiment 2 is found to be the best, obviously better than that of the gas sensors in other embodiments, and is more representative. Therefore, as shown in FIGS. 1 to 7, the present patent is focused on the comparative study of the gas sensing characteristics of the sensors of example 2 and comparative examples 1 and 2, and clearly and typically shows the synthesis of NiO/NiCr by hydrothermal method2O4Compared with the uncomplexed pure-phase NiO sensitive material, the nano composite sensitive material has excellent xylene gas sensing characteristics. In addition, the sensitivity to the device (P-type semiconductor) is defined in the test reducing gas as its resistance value (R) in the gas to be testedg) And resistance value in air (Ra) The ratio of the magnitudes is S ═ Rg/Ra. In the testing process, a static testing system is used for testing, the device is placed in a 50-80L air box, a certain amount of gas to be tested is injected inwards, resistance value change of the gas to be tested is observed and recorded, and a corresponding sensitivity value is obtained through calculation.
Detailed Description
Comparative example 1:
with Cr not compositely modified2O3The method for manufacturing the xylene sensor by using the nano particles as sensitive materials comprises the following specific manufacturing processes:
(1) firstly, measuring 30mL of deionized water, pouring the deionized water into a beaker, and continuously stirring;
(2) 0.53g of CrCl3·6H2Adding O and 0.28g of HMT (hexamethylenetetramine) into a beaker filled with deionized water, continuously stirring until the HMT and the hexamethylenetetramine are completely dissolved, and adding 2mL of ethanolamine into the beaker;
(3) transferring the solution into a hydrothermal kettle, keeping the solution at 180 ℃ for 8 hours, taking out the solution, naturally cooling the solution to room temperature, centrifugally cleaning the generated precipitate for multiple times by using deionized water and ethanol, drying the precipitate at room temperature, and calcining the dried precipitate at 500 ℃ for 3 hours to obtain pure-phase Cr2O3Nano sensitive material powder, the mass of the product is 0.14 g;
(4) taking a proper amount of pure-phase Cr prepared by a hydrothermal method2O3Mixing the nano sensitive material powder with deionized water, grinding to form pasty slurry, dipping a small amount of slurry, and uniformly coating the slurry on the outer surface of Al with 2 annular gold electrodes2O3Forming a sensitive material film on the surface of the ceramic tube, and enabling the sensitive material to completely cover the annular gold electrode, wherein the thickness of the sensitive material film is 46 mu m;
(5) baking under infrared lamp for 25 min, drying the sensitive material, and adding Al2O3Calcining the ceramic tube at 500 ℃ for 3 hours; then, a nichrome coil having a resistance value of 31 Ω was passed through Al2O3The interior of the ceramic tube is used as a heating wire, and finally the device is welded and packaged according to a general indirectly heated gas sensitive element,thereby obtaining the NiO nano structure which is not compositely modified and used as a sensitive material for manufacturing the xylene sensor.
Wherein, Al2O3The ceramic tube had a length of 4.2mm, an outer diameter of 1.3mm and an inner diameter of 0.9 mm. The width of the gold electrodes is 0.2mm, and the spacing is 0.5 mm.
Comparative example 2:
the method is characterized in that NiO nano-particles which are not subjected to composite modification are used as sensitive materials to manufacture the xylene sensor, and the specific manufacturing process comprises the following steps:
(1) firstly, measuring 30mL of deionized water, pouring the deionized water into a beaker, and continuously stirring;
(2) 0.48g of NiCl2·6H2Adding O and 0.28g of HMT (hexamethylenetetramine) into a beaker filled with deionized water, continuously stirring until the HMT and the hexamethylenetetramine are completely dissolved, and adding 2mL of ethanolamine into the beaker;
(3) transferring the solution into a hydrothermal kettle, keeping the solution at 180 ℃ for 8 hours, taking out the solution, naturally cooling the solution to room temperature, centrifugally cleaning the generated precipitate for many times by using deionized water and ethanol, drying the precipitate at room temperature, and calcining the dried precipitate at 500 ℃ for 3 hours to obtain pure-phase NiO nano sensitive material powder, wherein the mass of the product is 0.09 g;
(4) mixing a proper amount of pure-phase NiO nano sensitive material powder prepared by a hydrothermal method with deionized water, grinding to form pasty slurry, dipping a small amount of slurry, and uniformly coating the paste on Al with 2 annular gold electrodes on the outer surface2O3Forming a sensitive material film on the surface of the ceramic tube, and enabling the sensitive material to completely cover the annular gold electrode, wherein the thickness of the sensitive material film is 46 mu m;
(5) baking under infrared lamp for 25 min, drying the sensitive material, and adding Al2O3Calcining the ceramic tube at 500 ℃ for 3 hours; then, a nichrome coil having a resistance value of 31 Ω was passed through Al2O3And finally, welding and packaging the device according to a general indirectly heated gas sensitive element by taking the ceramic tube as a heating wire, thereby obtaining the device based on the NiO nano structure which is not subjected to composite modification and used as a sensitive material for manufacturing the xylene sensor.
Wherein, Al2O3The ceramic tube had a length of 4.2mm, an outer diameter of 1.3mm and an inner diameter of 0.9 mm. The width of the gold electrodes is 0.2mm, and the spacing is 0.5 mm.
Example 1:
with NiO/NiCr2O4The specific manufacturing process of the xylene gas sensor with the nano composite structure as a sensitive material comprises the following steps:
(1) firstly, measuring 30mL of deionized water, pouring the deionized water into a beaker, and continuously stirring;
(2) 0.05g of CrCl3·6H2O，0.47g NiCl2·6H2Adding O and 0.28g of HMT (hexamethylenetetramine) into a beaker filled with deionized water, continuously stirring until the HMT and the hexamethylenetetramine are completely dissolved, and adding 2mL of ethanolamine into the beaker;
(3) transferring the solution into a hydrothermal kettle, keeping the solution at 180 ℃ for 8 hours, taking out the solution, naturally cooling the solution to room temperature, centrifugally cleaning the generated precipitate for multiple times by using deionized water and ethanol, drying the precipitate at room temperature, and calcining the dried precipitate at 500 ℃ for 3 hours to obtain NiO/NiCr2O4Nano composite structure powder, the mass of the product is 0.11 g;
(4) taking a proper amount of NiO/NiCr prepared by a hydrothermal method2O4Mixing the nano composite structure powder (8.9mg) with deionized water (50 μ L), grinding to form paste slurry, dipping a small amount of slurry, and uniformly coating Al with 2 annular gold electrodes on the outer surface2O3Forming a sensitive material film on the surface of the ceramic tube, and enabling the sensitive material to completely cover the annular gold electrode, wherein the thickness of the sensitive material film is 47 microns;
(5) baking under infrared lamp for 25 min, drying the sensitive material, and adding Al2O3Calcining the ceramic tube at 500 ℃ for 3 hours; then, a nichrome coil having a resistance value of 31 Ω was passed through Al2O3The interior of the ceramic tube is used as a heating wire, and finally the device is welded and encapsulated according to a general indirectly heated gas sensitive element, so that NiO/NiCr-based gas sensor is obtained2O4Xylene gas sensor of sensitive material of nanometer composite structure.
Wherein, Al2O3The ceramic tube had a length of 4.2mm, an outer diameter of 1.3mm and an inner diameter of 0.9 mm. The width of the gold electrodes is 0.2mm, and the spacing is 0.5 mm.
Example 2:
with NiO/NiCr2O4The specific manufacturing process of the xylene gas sensor with the nano composite structure as a sensitive material comprises the following steps:
(1) firstly, measuring 30mL of deionized water, pouring the deionized water into a beaker, and continuously stirring;
(2) 0.13g of CrCl3·6H2O，0.47g NiCl2·6H2Adding O and 0.28g of HMT (hexamethylenetetramine) into a beaker filled with deionized water, continuously stirring until the HMT and the hexamethylenetetramine are completely dissolved, and adding 2mL of ethanolamine into the beaker;
(3) transferring the solution into a hydrothermal kettle, keeping the solution at 180 ℃ for 8 hours, taking out the solution, naturally cooling the solution to room temperature, centrifugally cleaning the generated precipitate for multiple times by using deionized water and ethanol, drying the precipitate at room temperature, and calcining the dried precipitate at 500 ℃ for 3 hours to obtain NiO/NiCr2O4Nano composite structure powder, the mass of the product is 0.21 g;
(4) taking a proper amount of NiO/NiCr prepared by a hydrothermal method2O4Mixing the nano composite structure powder (9.3mg) with deionized water (50 μ L), grinding to form paste slurry, dipping a small amount of slurry, and uniformly coating Al with 2 annular gold electrodes on the outer surface2O3Forming a sensitive material film on the surface of the ceramic tube, and enabling the sensitive material to completely cover the annular gold electrode, wherein the thickness of the sensitive material film is 48 microns;
(5) baking under infrared lamp for 25 min, drying the sensitive material, and adding Al2O3Calcining the ceramic tube at 500 ℃ for 3 hours; then, a nichrome coil having a resistance value of 31 Ω was passed through Al2O3The interior of the ceramic tube is used as a heating wire, and finally the device is welded and encapsulated according to a general indirectly heated gas sensitive element, so that NiO/NiCr-based gas sensor is obtained2O4Xylene gas sensor of sensitive material of nanometer composite structure.
Wherein, Al2O3The ceramic tube had a length of 4.2mm, an outer diameter of 1.3mm and an inner diameter of 0.9 mm. The width of the gold electrodes is 0.2mm, and the spacing is 0.5 mm.
Example 3:
with NiO/NiCr2O4The specific manufacturing process of the xylene gas sensor with the nano composite structure as a sensitive material comprises the following steps:
(1) firstly, measuring 30mL of deionized water, pouring the deionized water into a beaker, and continuously stirring;
(2) 0.35g of CrCl3·6H2O，0.47g NiCl2·6H2Adding O and 0.28g of HMT (hexamethylenetetramine) into a beaker filled with deionized water, continuously stirring until the HMT and the hexamethylenetetramine are completely dissolved, and adding 2mL of ethanolamine into the beaker;
(3) transferring the solution into a hydrothermal kettle, keeping the solution at 180 ℃ for 8 hours, taking out the solution, naturally cooling the solution to room temperature, centrifugally cleaning the generated precipitate for multiple times by using deionized water and ethanol, drying the precipitate at room temperature, and calcining the dried precipitate at 500 ℃ for 3 hours to obtain NiO/NiCr2O4Nano composite structure powder, the mass of the product is 0.29 g;
(4) taking a proper amount of NiO/NiCr prepared by a hydrothermal method2O4Mixing the nano composite structure powder (9.8mg) with deionized water (50 μ L), grinding to form paste slurry, dipping a small amount of slurry, and uniformly coating Al with 2 annular gold electrodes on the outer surface2O3Forming a sensitive material film on the surface of the ceramic tube, and enabling the sensitive material to completely cover the annular gold electrode, wherein the thickness of the sensitive material film is 47 microns;
(5) baking under infrared lamp for 25 min, drying the sensitive material, and adding Al2O3Calcining the ceramic tube at 500 ℃ for 3 hours; then, a nichrome coil having a resistance value of 31 Ω was passed through Al2O3The interior of the ceramic tube is used as a heating wire, and finally the device is welded and encapsulated according to a general indirectly heated gas sensitive element, so that NiO/NiCr-based gas sensor is obtained2O4Xylene gas sensor of sensitive material of nanometer composite structure.
Wherein，Al2O3The ceramic tube had a length of 4.2mm, an outer diameter of 1.3mm and an inner diameter of 0.9 mm. The width of the gold electrodes is 0.2mm, and the spacing is 0.5 mm.
Claims (2)
1. NiO/NiCr-based2O4The preparation method of the xylene gas sensor of the nano composite sensitive material comprises the following steps:
(1) 0.05-0.35 g of CrCl3.6H2O、0.35～0.65g NiCl2·6H2Adding O and 0.21-0.41 g of hexamethylenetetramine into 20-40 mL of deionized water, stirring until the O and the hexamethylenetetramine are completely dissolved, and adding 1-4 mL of ethanolamine into the deionized water;
(2) carrying out hydrothermal reaction on the solution at 160-200 ℃ for 6-10 hours, taking out, naturally cooling to room temperature, carrying out multiple centrifugal cleaning on the generated precipitate by using deionized water and ethanol, drying at room temperature, and finally calcining at 400-600 ℃ for 2-4 hours to obtain NiO/NiCr2O4Nano composite sensitive material powder;
(3) taking 8-20 mg of NiO/NiCr2O4Mixing the nano composite sensitive material powder with 40-100 mu L of deionized water, grinding to form pasty slurry, dipping a small amount of slurry, and uniformly coating the slurry on Al with two parallel, annular and mutually separated gold electrodes on the outer surface2O3Forming a sensitive material film on the surface of the ceramic tube substrate, and enabling the sensitive material to completely cover the annular gold electrode, wherein the thickness of the sensitive material film is 40-50 mu m;
(2) baking for 20-40 minutes under an infrared lamp, and drying the sensitive material, and then adding Al2O3Calcining the ceramic tube at 400-600 ℃ for 2-4 hours; then enabling the nichrome coil with the resistance value of 30-40 omega to penetrate through Al2O3The ceramic tube is internally used as a heating wire, and finally welding and packaging are carried out according to an indirectly heated gas sensitive element, so that NiO/NiCr-based gas sensor is obtained2O4Xylene gas sensor of nano composite sensitive material.
2. The NiO/NiCr-based NiCr material of claim 12O4Nano meterThe preparation method of the xylene gas sensor made of the composite sensitive material is characterized by comprising the following steps: al (Al)2O3The ceramic tube has a length of 4-4.5 mm, an outer diameter of 1.2-1.5 mm, an inner diameter of 0.8-1.0 mm, a width of 0.15-0.3 mm and a spacing of 0.4-0.6 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810464724.XA CN108872324B (en) | 2018-05-16 | 2018-05-16 | Xylene gas sensor based on nano composite sensitive material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810464724.XA CN108872324B (en) | 2018-05-16 | 2018-05-16 | Xylene gas sensor based on nano composite sensitive material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108872324A CN108872324A (en) | 2018-11-23 |
| CN108872324B true CN108872324B (en) | 2020-03-03 |
Family
ID=64333964
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810464724.XA Active CN108872324B (en) | 2018-05-16 | 2018-05-16 | Xylene gas sensor based on nano composite sensitive material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108872324B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110455891B (en) * | 2019-08-20 | 2021-06-04 | 吉林大学 | Based on CoWO4-Co3O4Dimethyl benzene gas sensor of heterojunction nano structure sensitive material and preparation method thereof |
| CN113671010B (en) * | 2021-08-18 | 2022-04-01 | 吉林大学 | In based on mesoporous2O3Triethylamine gas sensor of-NiO sensitive material and preparation method thereof |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7887685B2 (en) * | 2005-07-14 | 2011-02-15 | Caterpillar Inc. | Multilayer gas sensor having dual heating zones |
| CN103604853B (en) * | 2013-11-21 | 2015-07-08 | 吉林大学 | Mixed-potential type NO2 sensor with mesh-strip structured YSZ (yttria-stabilized zirconia) substrate serving as conductive layer and preparation method for mixed-potential type NO2 sensor |
| CN105548275A (en) * | 2016-01-14 | 2016-05-04 | 吉林大学 | Acetone sensor based on NiO/ZnO heterostructure nanoflower sensitive material and preparation method of acetone sensor |
| CN106950274A (en) * | 2017-04-06 | 2017-07-14 | 吉林大学 | A kind of dimethylbenzene gas sensor for the NiO graded structures nanometer bouquet sensitive material that adulterated based on Sn and preparation method thereof |
| CN107607591B (en) * | 2017-09-11 | 2019-12-10 | 吉林大学 | SnO 2 -modified NiO nano-structure sensitive material-based ultra-sensitive toluene gas sensor and preparation method thereof |
-
2018
- 2018-05-16 CN CN201810464724.XA patent/CN108872324B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN108872324A (en) | 2018-11-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sun et al. | Rapid and stable detection of carbon monoxide in changing humidity atmospheres using clustered In2O3/CuO nanospheres | |
| Gao et al. | A formaldehyde sensor: Significant role of pn heterojunction in gas-sensitive core-shell nanofibers | |
| Wang et al. | Construction of ZnO/SnO2 heterostructure on reduced graphene oxide for enhanced nitrogen dioxide sensitive performances at room temperature | |
| Miller et al. | Nanoscale metal oxide-based heterojunctions for gas sensing: A review | |
| Ahmad et al. | Recent progress and perspectives of gas sensors based on vertically oriented ZnO nanomaterials | |
| Zhang et al. | Room temperature NO2 gas sensor based on porous Co3O4 slices/reduced graphene oxide hybrid | |
| Zhang et al. | Room-temperature benzene sensing with Au-doped ZnO nanorods/exfoliated WSe2 nanosheets and density functional theory simulations | |
| Kim et al. | Highly sensitive and selective gas sensors using p-type oxide semiconductors: Overview | |
| Poloju et al. | Improved gas sensing performance of Al doped ZnO/CuO nanocomposite based ammonia gas sensor | |
| Ding et al. | Low-operating temperature ammonia sensor based on Cu 2 O nanoparticles decorated with p-type MoS 2 nanosheets | |
| Liu et al. | Ultrasensitive NO2 detection utilizing mesoporous ZnSe/ZnO heterojunction-based chemiresistive-type sensors | |
| Wang et al. | Enhanced HCHO gas sensing properties by Ag-loaded sunflower-like In 2 O 3 hierarchical nanostructures | |
| Li et al. | Highly sensitive and selective triethylamine gas sensor based on hierarchical radial CeO2/ZnO nn heterojunction | |
| Shi et al. | Facile synthesis of reduced graphene oxide/hexagonal WO3 nanosheets composites with enhanced H2S sensing properties | |
| Zeng et al. | Selective detection of methanol by zeolite/Pd-WO3 gas sensors | |
| Yin et al. | Opposite sensing response of heterojunction gas sensors based on SnO2–Cr2O3 nanocomposites to H2 against CO and its selectivity mechanism | |
| Wang et al. | Nanoparticles-assembled Co3O4 nanorods p-type nanomaterials: One-pot synthesis and toluene-sensing properties | |
| Chen et al. | Enhanced sensing performance to toluene and xylene by constructing NiGa2O4-NiO heterostructures | |
| Mousavi et al. | Enormous enhancement of Pt/SnO2 sensors response and selectivity by their reduction, to CO in automotive exhaust gas pollutants including CO, NOx and C3H8 | |
| Wang et al. | W-doped NiO as a material for selective resistive ethanol sensors | |
| Zhou et al. | Constructing hierarchical heterostructured Mn3O4/Zn2SnO4 materials for efficient gas sensing reaction | |
| Cai et al. | Enhanced performance of the tangerines-like CuO-based gas sensor using ZnO nanowire arrays | |
| Anajafi et al. | Acetone sensing behavior of p-SmFeO3/n-ZnO nanocomposite synthesized by thermal treatment method | |
| Wang et al. | Mesoporous WO 3 modified by Au nanoparticles for enhanced trimethylamine gas sensing properties | |
| Zhang et al. | Interfacial energy barrier tuning of hierarchical Bi2O3/WO3 heterojunctions for advanced triethylamine sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |