CN106168598B - One kind being based on YSZ and CoTa2O6Sensitive electrode blendes together electric potential type NO2Sensor, preparation method and applications - Google Patents

Abstract

A hybrid potentiometric high-temperature NO ₂ sensor based on YSZ and CoTa ₂ O ₆ sensitive electrodes, its preparation method and its application in automobile exhaust gas monitoring. The sensor is sequentially composed of an _Al2O3 ceramic plate with a Pt heating electrode, a _YSZ substrate, a Pt reference electrode, and a sensitive electrode; the reference electrode and the sensitive electrode are separately and symmetrically prepared at both ends of the upper surface of the YSZ substrate, and under the YSZ substrate. The surface is bonded with an Al ₂ O ₃ ceramic plate with a Pt heating electrode; the material of the sensitive electrode is CoTa ₂ O ₆ . In the present invention, YSZ is used as the ion-conducting layer, CoTa ₂ O ₆ composite oxide material with high electrochemical catalytic activity is used as the sensitive electrode, and the microscopic morphology of the sensitive electrode is changed by different calcination temperatures (800°C-1200°C), and Construct sensor devices separately, and obtain devices with higher sensitivity performance by comparing the response value to NO ₂ at high temperature.

Description

A hybrid potential NO2 sensor based on YSZ and CoTa2O6 sensitive electrodes preparation method and its application

technical field

The invention belongs to the technical field of gas sensors, and in particular relates to a hybrid potential type high-temperature NO ₂ sensor based on YSZ and CoTa ₂ O ₆ sensitive electrodes, a preparation method and its application in automobile exhaust gas monitoring.

Background technique

With the increasing number of automobiles, the environmental pollution caused by automobile exhaust emissions and the increasingly scarce resources have become two major challenges for the sustainable development of the automobile industry. Therefore, in order to meet the challenge, countries around the world have successively proposed stricter vehicle emission standards to limit the emission of toxic and harmful exhaust gases. In addition, in order to improve fuel combustion efficiency and reduce carbon dioxide emissions, NO _x storage catalytic systems are installed on lean-burn or direct injection engines to compensate for the low NO _x removal capacity of traditional three-phase catalytic systems. However, when the NO _x storage capacity of the catalyst reaches saturation, a high concentration of hydrocarbons needs to be supplied to the catalyst to restore the storage capacity. Therefore, low-cost, high-stability, high-strength and high-sensitivity _NOx sensors should be installed at both ends of the catalyst to monitor the concentration of _NOx in real time, so as to adjust the regeneration timing of the catalyst. Since the vehicle exhaust after-treatment system is often in the harsh working condition of high temperature and high humidity, it is required that the sensor should be able to withstand the environment of high temperature and high humidity. Fortunately, hybrid potentiometric gas sensors based on YSZ and metal oxide sensitive electrodes can meet the above requirements.

The sensitive mechanism of the stable zirconia-based mixed potential _NO2 sensor is: _NO2 in the atmosphere diffuses to the three-phase reaction interface through the sensitive electrode layer. During the diffusion process, the concentration of _NO2 will gradually decrease due to the reaction (1), and the oxidation The porosity of the material sensitive electrode will determine the reduction degree of _NO2 concentration. At the three-phase interface of gas/sensing electrode/YSZ, the electrochemical reduction reaction of NO and the electrochemical oxidation reaction of oxygen occur simultaneously, and the reactions ( ₂ ) and (3) constitute a local battery, when both reaction rates are equal , the reaction reaches equilibrium, and a mixed potential is formed on the sensitive electrode, and the potential difference between it and the reference electrode is used as the detection signal of the sensor. The magnitude of the detection signal is determined by the rate of electrochemical reactions (2) and (3), and the reaction rate depends on the electrochemical and chemical catalytic activity of the sensitive electrode material, the microstructure of the electrode material (such as the porosity, particle size, and morphology of the material). Wait).

The reaction formula is as follows:

NO ₂ →NO+1/2O ₂ (1)

NO ₂ + ^2e- →NO+O ^2- (2)

O ^2- → 1/2O ₂ +2e ^- (3)

At present, in order to prepare sensors with higher sensitivity characteristics, most researchers at home and abroad are devoted to the research of sensitive electrode materials. For example, the YSZ-based mixed potential NO ₂ sensor made by our research group with Cr ₂ O ₃ -WO ₃ as the sensitive electrode material has a mixed potential value of 52mV for 100ppm NO ₂ (Quan Diao, Chengguo Yin, Yingwei Liu, JianguoLi, Xun Gong, Xishuang Liang, Shiqi Yang, Hong Chen, Geyu Lu, Mixed-potential-type NO ₂ sensor using stabilized zirconia and Cr ₂ O ₃ -WO ₃ nanocomposites, Sensor and Actuators B 180(2013) 90-95). Although this _NO2 sensor has acceptable sensitive performance, it is still very necessary to continue to develop sensitive electrode materials with high electrochemical catalytic activity for _NO2 gas detection.

Contents of the invention

The purpose of the present invention is to provide a hybrid potential type high-temperature NO ₂ sensor based on YSZ and CoTa ₂ O ₆ sensitive electrodes, a preparation method and its application in automobile exhaust gas monitoring. In addition to high sensitivity, the sensor obtained by the invention also has lower detection limit, good selectivity, moisture resistance and stability.

The _NO2 sensor involved in the present invention is based on the solid electrolyte YSZ and high electrochemical catalytic performance _CoTa2O6 composite oxide material is a _novel high-temperature _NO2 sensor constructed by the sensitive electrode, YSZ ( _ZrO2 (doping mass fraction 8% Y ₂ O ₃ )) as the ion-conducting layer.

A hybrid potential _NO2 sensor based on YSZ and _{CoTa2O6 sensitive} electrodes according to the present invention, as shown in Figure 1, consists of an _Al2O3 ceramic plate with a _Pt heating electrode, a YSZ substrate, a Pt reference Composition of electrodes and sensitive electrodes; the reference electrode and the sensitive electrode are separated from each other and symmetrically prepared at both ends of the upper surface of the YSZ substrate, and the lower surface of the YSZ substrate is bonded with an Al ₂ O ₃ ceramic plate with a Pt heating electrode; the sensitive electrode The material is CoTa ₂ O ₆ , which is prepared by the following method:

Weigh 0.5-2 mmol of Ta ₂ O ₅ , dissolve it in 30-60 mL of hydrofluoric acid aqueous solution with a mass fraction of 40-50%, stir at 60-90°C for 12-24 hours; mix 15-20 mL, Add ammonia water with a mass concentration of 25-28% dropwise to the above solution, adjust the pH value of the reaction system to 8-10, age for 12-14 hours, filter and wash to neutrality, and obtain a white precipitate; the above white Dissolve the precipitate in the aqueous solution of citric acid, continue to stir at 60-80°C for 1-2 hours, add CoCl ₂ ·6H ₂ O aqueous solution and continue to stir until it becomes a gel; bake the obtained gel under vacuum at 80-90°C Dry for 12-24 hours to obtain a xerogel, and finally calcinate the obtained xerogel at 800-1200°C for 2-4 hours to obtain a CoTa ₂ O ₆ sensitive electrode material; where CoCl ₂ 6H ₂ O and Ta ₂ O The molar ratio of ₅ is 1:1, and the molar ratio of citric acid and Ta ₂ O ₅ is 2-5:1.

_NO of the present invention The preparation steps of the sensor are as follows:

(1) Making a Pt reference electrode: Use Pt paste on one end of the upper surface of the YSZ substrate to make a 15-20 μm thick Pt reference electrode, and at the same time fold a Pt wire in half and stick it to the middle of the reference electrode as an electrode lead, and then connect the YSZ The substrate is baked at 90-120°C for 1-2 hours, and then the YSZ substrate is calcined at 1000-1200°C for 1-2 hours to remove terpineol in the platinum slurry, and finally lower to room temperature;

(2) Make a CoTa ₂ O ₆ sensitive electrode: adjust the CoTa ₂ O ₆ sensitive electrode material into a slurry with deionized water, with a mass concentration of 2 to 20%; place the slurry on the upper surface of the YSZ substrate symmetrical to the reference electrode A sensitive electrode with a thickness of 20-30 μm is prepared on the platinum point connected to the other end of the platinum wire;

(3) Calcining the above-mentioned YSZ substrate prepared with the reference electrode and the sensitive electrode at 800-1000°C for 1-3 hours; the preferred heating rate during high-temperature calcination is 1-2°C/min;

(4) Preparation of inorganic binder: Measure 2-4 mL of water glass (Na ₂ SiO ₃ ·9H ₂ O), weigh 0.7-1.0 g of Al ₂ O ₃ powder, mix water glass and Al ₂ O ₃ powder Mix and stir evenly to obtain the desired inorganic binder;

₍ 5) Use an inorganic adhesive to bond the lower surface of the YSZ substrate and the _Al2O3 ceramic plate with a Pt heating electrode;

Among them, the Al ₂ O ₃ ceramic plate with Pt heating electrode is obtained by screen printing Pt on the Al ₂ O ₃ ceramic plate, and the Al ₂ O ₃ ceramic plate with Pt heating electrode is used together as the heating plate of the device;

(6) Welding and packaging the bonded devices, so as to prepare the hybrid potential NO ₂ sensor based on YSZ and CoTa ₂ O ₆ sensitive electrodes of the present invention.

In the present invention, YSZ is used as the ion-conducting layer, CoTa ₂ O ₆ composite oxide material with high electrochemical catalytic activity is used as the sensitive electrode, and the microscopic morphology of the sensitive electrode is changed by different calcination temperatures (800°C-1200°C), and Construct sensor devices separately, and obtain devices with higher sensitivity performance by comparing the response value to NO ₂ at high temperature.

Advantages of the present invention:

(1) The sensor uses a typical solid electrolyte - stabilized zirconia (YSZ), which has good thermal and chemical stability and can detect NO ₂ in harsh environments;

(2) The high-performance composite oxide CoTa ₂ O ₆ was prepared by the sol-gel method as the sensitive electrode of the sensor, the preparation method is simple, and it is conducive to mass industrial production.

(3) By changing different calcination temperatures (800°C to 1200°C), sensitive electrode layers with different pore structures are obtained, thereby optimizing the microstructure of the sensitive electrodes. By comparing the performance of sensors constructed with different calcination temperature-sensitive electrode materials, it is found that 1000 The YSZ-based hybrid potential device with calcined CoTa ₂ O ₆ as the sensitive electrode shows the highest response to NO ₂ at high temperature, and has a lower detection limit, good sensitivity, selectivity, repeatability, and humidity resistance and stability, and has potential application prospects in automobile exhaust monitoring.

Description of drawings

Figure 1: Schematic diagram of the structure of the YSZ-based hybrid _{potentiometric} NO sensor (a) and heating plate (b) according to the present invention.

Names of each part: CoTa ₂ O ₆ sensitive electrode 1, YSZ substrate 2, Pt reference electrode 3, Pt wire 4, Pt point 5, Al ₂ O ₃ ceramic plate with Pt heating electrode 6, inorganic binder 7.

Figure 2: XRD patterns of three sensitive electrode materials prepared in the present invention. (Wherein, the abscissa is the angle, and the ordinate is the intensity)

As shown in Figure 2, it is the XRD patterns of CoTa ₂ O ₆ sensitive electrode materials at different calcination temperatures. By comparing with the standard spectra, the three synthesized sensitive electrode materials are all consistent with the standard card JCPDS (File No. 84-2063) , is a tetragonal three-rutile structure composite oxide. It shows that the sensitive electrode material prepared by our invention is CoTa ₂ O ₆ material.

Figure 3: SEM images of sensitive electrode materials prepared by the present invention at different calcination temperatures.

As shown in Figure 3, a: 800°C, b: 1000°C, c: SEM images of CoTa ₂ O ₆ sensitive electrode materials calcined at 1200°C, it can be seen from the figure that with the increase of calcination temperature, the particle size It can be seen that changing the calcination temperature of the sensitive material can change the microscopic morphology of the sensitive electrode, and the porosity of the electrode is conducive to the diffusion of gas.

Figure 4: Comparison of the response value of the sensor to 100ppm NO ₂ using CoTa ₂ O ₆ calcined at 800, 1000 and 1200°C as the sensitive electrode material. (The abscissa is the potential difference, the ordinate is different electrode materials, and the working temperature is 650 degrees)

The sensitive performance test of the device adopts a static test method (the specific process is shown in the embodiment), and the response value of the sensor is represented by ΔV=V _NO2 −V _air . As shown in Figure 4, it is a comparison chart of the response values of the devices made in Examples 1, 2, and 3 to 100ppm NO _{2 .} The responses for ₂ are 93, 62 and 54mV, respectively. It can be seen that the YSZ-based hybrid potentiometric _NO sensor with CoTa ₂ O ₆ calcined at 1000 °C as the sensitive electrode material has the highest response value.

Figure 5: Sensitivity curves _of the sensor to _NO2 using _CoTa2O6 calcined at 1000 °C as the sensitive electrode material. (Wherein, the abscissa is the NO ₂ concentration, the ordinate is the potential difference, the working temperature is 650 degrees, and the inset is the sensitivity curve of the current sensor to 0.5-5ppm NO ₂ ).

The sensitivity of the sensor is the slope of the linear relationship between the sensor's response value and the corresponding concentration logarithm within a certain measurement concentration range. As shown in Figure 5, it is the sensitivity curve of the sensor to NO ₂ using CoTa ₂ O ₆ calcined at 1000°C as the sensitive electrode material. It can be seen from the figure that the sensitivity of the device to 5-500ppm NO ₂ is 80mV/decade , the minimum can detect 500ppb NO ₂ , this sensor shows good sensitivity and low detection limit.

_Figure 6: Selectivity of the sensor utilizing _CoTa2O6 calcined at 1000 °C as the sensitive electrode material. (Wherein, the abscissa is the potential difference, the ordinate is the test gas, and the illustration is an enlarged view of ethylene, methane and hydrogen)

As shown in Figure 6, the selectivity of the sensor for 1000°C calcined _CoTa2O6 as a sensitive electrode material, it can be seen from the _figure that the device exhibited the highest response value for 50 and 100ppm _NO2 , and for other gases The response values are all low, which shows that the device has good selectivity.

Figure 7: Humidity effect of the sensor with _CoTa2O6 calcined at 1000 °C as _the sensitive electrode material. (Wherein, the abscissa is the relative humidity, and the ordinate is the potential difference)

The sensor humidity test refers to the change of the response value of the device to 100ppm _NO2 under different humidity (in the range of 20-98% humidity). As shown in Figure 7, it is the response of the device with CoTa ₂ O ₆ calcined at 1000°C as the sensitive electrode material to 100ppm NO ₂ at different humidity. It can be seen from the figure that the device is in the humidity range of 20-98%. , the change in response to 100ppm _NO2 is less than 10.7%, indicating that the sensor has good humidity resistance.

Figure 8: Stability of the sensor with _CoTa2O6 calcined at 1000 _° C as the sensitive electrode material. (Wherein, the abscissa is time, and the ordinate is the potential difference value and potential difference change amount respectively)

The stability test of the device is to keep the sensor at a working temperature of 650 degrees. After 20 days of continuous high temperature testing, the response values to 50, 100 and 200 ppm NO ₂ are used as standards. During the test, a point is taken every two days. to record changes over a 20-day period. As shown in Figure 8, it is the stability test of the device using CoTa ₂ O ₆ calcined at 1000°C as the sensitive electrode material within 20 days. ₂ The fluctuation range of the response value is less than 10.2%, indicating that the device has good stability.

Detailed ways

Example 1:

The CoTa ₂ O ₆ material was prepared by the sol-gel method, and the prepared CoTa ₂ O ₆ was calcined at 1000°C as a sensitive electrode material to make a YSZ-based hybrid potentiometric sensor, and the gas-sensing performance of the sensor to NO ₂ was tested. The specific process as follows:

1. Make a Pt reference electrode: use Pt slurry to make a Pt reference electrode with a size of 0.5mm×2mm and a thickness of 15μm on one end of the upper surface of the YSZ substrate with a length and width of 2×2mm and a thickness of 0.2mm, and fold it in half with a Pt wire Then stick the electrode lead wire on the middle position of the reference electrode; then bake the YSZ substrate at 100°C for 1.5 hours, then calcinate the YSZ substrate at 1000°C for 1 hour, so as to eliminate the terpineol in the platinum paste, and finally reduce the to room temperature.

2. Fabrication of CoTa ₂ O ₆ sensitive electrodes: First, CoTa ₂ O ₆ materials were prepared by sol-gel method. Weigh 1mmolTa ₂ O ₅ , dissolve it in 50mL of hydrofluoric acid aqueous solution (mass fraction is 40%), stir at 80°C for 24 hours; ammoniacal water (mass concentration is 25%) is added dropwise to In the above solution, adjust the pH value to 9, age for 14 hours, filter and wash to neutrality, and obtain a white precipitate; dissolve the above white precipitate in an aqueous solution made of 0.6304g citric acid and 10mL water, at 80°C Stirring was continued for 2 hours, and 0.2379 g of CoCl ₂ ·6H ₂ O was added and stirring was continued until gel. The obtained gel-like substance was dried in a vacuum oven at 80° C. for 12 hours to obtain a xerogel, and finally calcined in a muffle furnace at 1000° C. for 2 hours to obtain 0.465 g of CoTa ₂ O ₆ sensitive electrode material.

Take 5mg of CoTa ₂ O ₆ powder and adjust it with 100 mg of deionized water to make a slurry, and coat the CoTa ₂ O ₆ slurry with a layer of 0.5mm The sensitive electrode with a size of ×2mm and a thickness of 20μm is also folded in half with a platinum wire and glued to the sensitive electrode to lead out the electrode lead.

The prepared YSZ substrate with the reference electrode and the sensitive electrode was heated to 800°C at a heating rate of 2°C/min and kept for 2h before cooling down to room temperature.

3. Bonding ceramic plates with heating electrodes. Use an inorganic binder (Al ₂ O ₃ and water glass Na ₂ SiO ₃ 9H ₂ O, prepared in a mass ratio of about 5:1) to bond the lower surface of the YSZ substrate (the side that is not coated with electrodes) with a tape of the same size Al ₂ O ₃ ceramic plates (length and width 2×2mm, thickness 0.2mm) with Pt heating electrodes are bonded;

4. Device welding and packaging. Weld the device on the hexagonal socket, put on the protective cover, and complete the hybrid potential NO ₂ sensor.

Example 2:

The CoTa ₂ O ₆ composite material calcined at 800°C was used as the sensitive electrode material to fabricate the NO ₂ sensor. The fabrication process is as follows:

The preparation process of the CoTa ₂ O ₆ sensitive electrode material calcined at 800°C and the device fabrication process are the same as those in Example 1.

Example 3:

The CoTa ₂ O ₆ composite material calcined at 1200°C is used as the sensitive electrode material to make the NO ₂ sensor, and the manufacturing process is as follows:

The preparation process of the CoTa ₂ O ₆ sensitive electrode material calcined at 1200°C and the device fabrication process are the same as those in Example 1.

Connect the sensor to the Rigol signal tester, place the sensor in air, 500ppb NO ₂ , 1ppm NO 2 , 2ppm NO ₂ , 5ppm NO ₂ , 10ppm NO ₂ , 20ppm _{NO 2 ,} 50ppm NO ₂ , 100ppm NO ₂ , 200ppm NO ₂ , 300ppm NO ₂ and 500ppm NO ₂ atmosphere for voltage signal test. The test method of the device adopts the traditional static test method, and the specific process is as follows:

1. Connect the sensor to the Rigol signal tester, and place the device in a test bottle filled with air with a volume of 1L to achieve stability, which is the electromotive force value ( _Vair ) of the device in air.

2. Quickly transfer the sensor to a test bottle containing NO ₂ gas at the concentration to be measured, until the response signal reaches a stability, which is the electromotive force value (V _NO2 ) of the device in NO ₂ .

3. Transfer the device back to the air bottle until it reaches a stable state, and the device completes a response recovery process. The electromotive force difference (ΔV=V _NO2 -V _air ) of the device in NO ₂ and air is the response value of the device to the concentration of NO ₂ . The slope of the linear relationship between the response value of the sensor in a certain measurement concentration range and the corresponding concentration logarithm is the sensitivity of the sensor.

Table 1 lists the response values of YSZ-based hybrid potentiometric sensors to 100ppm NO ₂ using CoTa ₂ O ₆ calcined at 800, 1000 and 1200°C as sensitive electrodes. It can be seen from the table that the device with CoTa ₂ O ₆ calcined at 1000°C as the sensitive electrode exhibited the highest response value, which was 93mV.

Table 2 lists the electromotive force of the YSZ-based hybrid potentiometric sensor made of CoTa ₂ O ₆ calcined at 1000°C as the sensitive electrode material in the atmosphere of different concentrations of NO ₂ and the difference of the electromotive force in the air with the concentration of NO ₂ change value. As can be seen from the table, the sensitivity (slope) of the device is 80mV/decade. It can be seen that the device composed of the new CoTa ₂ O ₆ sensitive electrode material calcined at 1000 ℃ developed by us showed good sensitivity to NO ₂ , and a YSZ-based hybrid potentiometric NO ₂ sensor with high sensitivity was obtained.

Table 1 Comparison of the response values of sensors to 100ppm NO ₂ using CoTa ₂ O ₆ calcined at 800, 1000 and 1200 °C as sensitive electrode materials

Table 2 Variation of ΔV with _NO concentration for devices using CoTa ₂ O ₆ calcined at 1000°C as sensitive electrodes

Claims (5)

1. one kind being based on YSZ and CoTa₂O₆Sensitive electrode blendes together electric potential type NO₂Sensor, successively by heating electrode with Pt Al₂O₃Ceramic wafer, YSZ substrates, Pt reference electrodes and sensitive electrode composition；Reference electrode and sensitive electrode are separate and symmetrical Ground is prepared in the both ends of YSZ upper surface of base plate, YSZ base lower surfaces and the Al with Pt heating electrodes₂O₃Ceramic wafer is bonded in one It rises；It is characterized in that：The material of sensitive electrode is CoTa₂O₆, it is prepared by the following method,

Weigh the Ta of 0.5~2mmol₂O₅, be dissolved in 30~60mL, mass fraction 40~50% hydrofluoric acid aqueous solution In, it is stirred 12~24 hours at 60~90 DEG C；The ammonium hydroxide of 15~20mL, mass concentration 25~28% are added drop-wise to dropwise above In solution, the pH value for adjusting reaction system is 8~10, is aged 12~14 hours, and through being filtered, washed neutrality, it is heavy to obtain white It forms sediment；The above white precipitate is dissolved in the aqueous solution of citric acid, continues stirring at 60~80 DEG C 1~2 hour, is added CoCl₂·6H₂O aqueous solutions continue stirring to gel；Obtained gel is dried 12~24 hours under 80~90 DEG C of vacuum conditions Xerogel is obtained, obtained xerogel is calcined 2~4 hours under the conditions of 800~1200 DEG C finally, obtains CoTa₂O₆Sensitive electrical Pole material；Wherein CoCl₂·6H₂O and Ta₂O₅Dosage molar ratio be 1：1, citric acid and Ta₂O₅Dosage molar ratio be 2~5： 1。

2. described in claim 1 a kind of based on YSZ and CoTa₂O₆Sensitive electrode blendes together electric potential type NO₂The preparation side of sensor Method, its step are as follows：

(1) Pt reference electrodes are made：The Pt of 15~20 μ m-thicks is made with reference to electricity using Pt slurries in one end of YSZ upper surface of base plate Pole, while will be sticked to after a Pt doublings on reference electrode centre position and being used as contact conductor, then by YSZ substrates 90~ It is toasted 1~2 hour under the conditions of 120 DEG C, then YSZ substrates is calcined 1~2 hour at 1000~1200 DEG C, excluded in platinum slurry Terpinol is finally down to room temperature；

(2) CoTa is made₂O₆Sensitive electrode：By CoTa₂O₆Sensitive electrode material is slurred material, mass concentration 2 with deionized water ~20%；The slurry is prepared 20 on the platinum point for connecting platinum filament with the other end of the symmetrical YSZ upper surface of base plate of reference electrode The sensitive electrode of~30 μ m-thicks；

(3) the YSZ substrates of reference electrode and sensitive electrode are calcined 1~3 hour at 800~1000 DEG C preparation；

(4) inorganic bond is used to heat the Al of electrode by YSZ base lower surfaces and with Pt₂O₃Ceramic wafer is bonded together；

(5) device bonded welded, encapsulated, YSZ and CoTa is based on to be prepared₂O₆Sensitive electrode blendes together Electric potential type NO₂Sensor.

3. as claimed in claim 2 a kind of based on YSZ and CoTa₂O₆Sensitive electrode blendes together electric potential type NO₂The preparation of sensor Method, it is characterised in that：Heating rate when calcining described in step (3) is 1~2 DEG C/min.

4. as claimed in claim 2 a kind of based on YSZ and CoTa₂O₆Sensitive electrode blendes together electric potential type NO₂The preparation of sensor Method, it is characterised in that：It is to measure 2~4mL of waterglass, and weigh Al₂O₃0.7~1.0g of powder, by waterglass and Al₂O₃Powder Body is mixed and stirred for uniformly, required inorganic bond being made.

5. described in claim 1 a kind of based on YSZ and CoTa₂O₆Sensitive electrode blendes together electric potential type NO₂Sensor is in car tail Application in gas monitoring.