阅读说明：本技术 一种采用水热法一步合成纳米SnO2气敏材料的方法 (One-step synthesis of nano SnO by adopting hydrothermal method2Method for producing gas-sensitive material ) 是由 闫纪宪 李清坤 王红娟 于 2021-01-13 设计创作，主要内容包括：本发明公开了一种纸采用水热法一步合成纳米SnO-2气敏材料的方法,包括以下步骤：以K-2SnO-3·3H-2O作为锡源,选取丙三醇作诱导剂,在180℃下反应20 h,一步合成粒径为30 nm～50 nm的SnO-2纳米球。本发明公开的SnO-2合成方法工艺简单、成本低,合成的SnO-2纳米材料粒径均一、分散性好、纯度高、结晶性好、气敏性能好。(The invention discloses a method for synthesizing nano SnO by one step through paper by adopting a hydrothermal method 2 A method of gas sensing materials comprising the steps of: with K 2 SnO 3 ·3H 2 O is used as a tin source, glycerol is selected as an inducer, the reaction is carried out for 20 hours at 180 ℃, and SnO with the particle size of 30 nm-50 nm is synthesized in one step 2 Nanospheres. SnO disclosed by the invention 2 The synthesis method has simple process and low cost, and the synthesized SnO 2 The nano material has the advantages of uniform particle size, good dispersibility, high purity, good crystallinity and good gas sensitivity.)

1. Method for synthesizing nano SnO (stannic oxide) by adopting hydrothermal method₂A method of gas sensing materials, comprising the steps of:

nano SnO₂And (4) preparing.

2. Under the condition of room temperature, 1.0 mmol-4.0 mmol K₂SnO₃·3H₂Dissolving O in 40 mL of deionized water, and magnetically stirring until all the O is dissolved; adding 10-20 mL of glycerol, and magnetically stirring for 20 min at normal temperature; transferring the solution into a 100 mL high-pressure reaction kettle, placing the high-pressure reaction kettle in an electric heating air blowing drying oven at 180 ℃, reacting for 20 h, taking out the high-pressure reaction kettle, cooling to room temperature, taking out the polytetrafluoroethylene lining, pouring off supernatant, respectively centrifugally washing precipitates for 3 times by using distilled water and absolute ethyl alcohol, drying in the drying oven at 80 ℃ for 2.5 h, and taking out required powder.

3. Placing the prepared powder in an alumina crucible tank, and calcining the powder in a muffle furnace for about 10 hours to synthesize nano SnO with excellent gas-sensitive property₂。

4. The method of claim 1, wherein the hydrothermal method is adopted to synthesize the nano SnO in one step₂A method of gas sensing materials, characterized by: the tin source is K₂SnO₃·3H₂And O, the inducer is glycerol.

5. The method of claim 1, wherein the hydrothermal method is adopted to synthesize the nano SnO in one step₂A method of gas sensing materials, characterized by: the ratio of glycerol to deionized water was (8 mL:40 mL) - (10 mL:20 mL).

6. The method of claim 1, wherein the hydrothermal method is adopted to synthesize the nano SnO in one step₂Method for gas-sensitive material, and gas-sensitive materialIs characterized in that: adding glycerol, and magnetically stirring for 20 min.

7. The method of claim 1, wherein the hydrothermal method is adopted to synthesize the nano SnO in one step₂A method of gas sensing materials, characterized by: the high-pressure reaction kettle is placed in an electric heating blowing dry box, and the reaction time is 20 hours.

Technical Field

The invention belongs to the technical field of nano materials, and relates to a method for synthesizing SnO in one step by adopting a hydrothermal synthesis method and glycerol as an inducer₂A nanosphere gas sensitive material.

Background

With the rapid development of national economy, the environmental pollution problem is becoming more serious, and the emission of toxic and polluting gases is increasing, which gradually affects the normal life of people, so that the gases must be effectively detected and controlled. At present, the main semiconductor metal oxide gas-sensitive materials used for gas sensors are: fe₂O₃、ZnO、WO₃、In₂O₃And SnO₂And the like. SnO₂The N-type semiconductor has the advantages of good stability, high sensitivity, low cost and the like as a broadband n-type semiconductor (Eg = 3.6 ev, 300K), and is most widely applied and researched in semiconductor metal oxide gas sensors.

SnO₂The gas-sensitive performance of the gas-sensitive material depends on the size, uniformity, stability and surface structure of tin dioxide nanoparticles, and the nano-scale SnO₂Has the advantages of small particle size, large specific surface area, uniform particle size, good stability and the like, and further improves the SnO₂The sensitivity and the gas selectivity of the gas sensitive material shorten the response and recovery time. At present, the research field mainly prepares the nano-structure SnO by a chemical vapor deposition method, a sol-gel method, a hydrothermal precipitation method and a template method₂The gas sensitive material has the defects of complicated steps, complex post-treatment process, high cost and the like.

SnO prepared by hydrothermal synthesis method₂The nanometer material is formed by one-time grain formation in the solvent, and does not need the later crystallization heat treatment, thereby effectively avoiding the defects of powder hard agglomeration, impurity mixing and the like caused by the later heat treatment. Therefore, how to synthesize SnO in one step by a simple and cheap hydrothermal synthesis method₂The nano gas-sensitive material is one of the difficulties of the challenges of numerous researchers, and has important theoretical value and practical significance.

Disclosure of Invention

In view of the traditional gas sensitive material and the existing SnO₂The synthesis method of the nano gas-sensitive material has a plurality of defects, and the invention aims to provide a method for synthesizing the nano gas-sensitive material by using K through a hydrothermal synthesis method₂SnO₃·3H₂O is used as a tin source, glycerol is selected as an inducer, the reaction is carried out for 20 hours at 180 ℃, and SnO with the particle size of 30 nm-50 nm is synthesized in one step₂Nanospheres. Solves the problems of the traditional gas-sensitive material and the existing SnO₂The synthesis technology has the problems of complicated steps, low material purity, poor powder dispersibility, easy impurity mixing, disordered particle size and the like, so that the method can be widely applied to the field of gas sensing.

The invention mainly adopts the following technical scheme:

the method mainly comprises the following steps:

nano SnO₂And (4) preparing. Under the condition of room temperature, 1.0 mmol-4.0 mmol K₂SnO₃·3H₂Dissolving O in 40 mL of deionized water, and magnetically stirring until all the O is dissolved; then, adding 10 mL-20 mL of glycerolAdding alcohol, and magnetically stirring at room temperature for 20 min; transferring the solution into a 100 mL high-pressure reaction kettle, placing the high-pressure reaction kettle in an electric heating air blowing drying oven at 180 ℃, reacting for 20 h, taking out the high-pressure reaction kettle, cooling to room temperature, taking out the polytetrafluoroethylene lining, pouring off supernatant, respectively centrifugally washing precipitates for 3 times by using distilled water and absolute ethyl alcohol, drying in the drying oven at 80 ℃ for 2.5 h, and taking out required powder. Placing the prepared powder in an alumina crucible tank, placing the alumina crucible tank into a muffle furnace to calcine for about 10 hours, wherein the temperature rise-temperature fall time curve of the muffle furnace is shown in figure 1, and synthesizing the nano SnO with excellent gas-sensitive property₂。

And (5) testing gas-sensitive performance. Dispersing a certain amount of sample to be detected into 200 muL of water solution, uniformly dispersing by ultrasonic, taking 10 muL, dropwise adding the sample to the surface of a sensing device, naturally drying, and then loading the sample into a sensing test system for carrying out related gas sensing performance test. The total gas flow rate was controlled by a gas flow meter to be constant at 200 sscm (standard cubic meter per minute) and the sensory test temperature was 350 ℃. Defining gas sensitivity as S =R _air/ R _gas(whereinR _airThe resistance value of the sensing material under air condition,R _gasresistance value of the sensing material under air condition), response timeT ₁The time required for the resistance change value of the sensing material to fall to 90% of the maximum difference value after the sensing gas enters, and the recovery timeT ₂The time required for the resistance change value of the sensing material to rise to 90% of the maximum difference value after the sensing gas is turned off.

The invention has the beneficial effects that:

adopts a one-step hydrothermal synthesis method and uses cheap K₂SnO₃·3H₂O is used as a tin source, and glycerol is selected as an inducer, so that the process is simple and the cost is low.

Synthetic SnO₂The nano material has the advantages of uniform particle size, good dispersibility, high purity, good crystallinity and good gas sensitivity.

Drawings

FIG. 1 is a graph of muffle furnace temperature rise-fall time.

FIG. 2 shows the obtained nmSnO₂Powder X-ray powder diffraction pattern of (1), and Rutile (Rutile) structure SnO₂The standard spectrum (JCPDS card number is 41-1445) is consistent, no impurity peak appears in the obtained XRD spectrum, and the nano SnO prepared is shown₂Has high purity and good crystallinity.

FIG. 3 is nano SnO prepared by example two₂The scanning electron microscope image clearly shows that the size distribution of the nano-spheres is relatively uniform, and the average particle diameter is 40 nm.

FIG. 4 is nano SnO prepared by example four under 120mA working current₂The change curve of the sensing sensitivity of the material to ethanol gas along with the increase of concentration (5-200 ppm). When the ethanol concentration was 50 ppm, the response time and recovery time were 21 s and 33 s, respectively. The inner diagram is nano SnO₂A linear relationship between sensitivity and concentration for ethanol gas sensing.

FIG. 5 shows nano SnO prepared in example four under 120mA working current₂The material has a curve chart of the change of the sensitivity of the n-butanol gas sensor along with the increase of the concentration (5-200 ppm). When the n-butanol concentration was 50 ppm, the response time and recovery time were 19 s and 31 s, respectively. The inner diagram is nano SnO₂A linear relationship between sensitivity and concentration for n-butanol gas sensing.

FIG. 6 is a graph of the stability of a gas sensitive material of a repeated test sensor continuously cycled 5 times in 100 ppm ethanol.

FIG. 7 is a graph of the stability of a gas sensitive material of a repeated test sensor in 100 ppm n-butanol with 5 cycles.

Detailed Description

The first embodiment is as follows:

nano SnO₂And (4) preparing. Under the condition of room temperature, adding 1.0mmol K₂SnO₃·3H₂Dissolving O in 40 mL of deionized water, and magnetically stirring until all the O is dissolved; then adding 20 mL of glycerol into the mixture, and magnetically stirring the mixture for 20 min at normal temperature; transferring the solution into a 100 mL high-pressure reaction kettle, placing the high-pressure reaction kettle in an electric heating blowing dry box at 180 ℃, reacting for 20 h, taking out the high-pressure reaction kettle, cooling the high-pressure reaction kettle to room temperature, taking out the polytetrafluoroethylene lining, pouring off the supernatant, and precipitatingCentrifuging and washing with distilled water and anhydrous ethanol for 3 times, drying in drying oven at 80 deg.C for 2.5 hr, and taking out the desired powder. Placing the prepared powder in an alumina crucible tank, putting the alumina crucible tank into a muffle furnace to calcine for about 10 hours, and synthesizing nano SnO₂。

Example two:

nano SnO₂And (4) preparing. Under the condition of room temperature, adding 1.0mmol K₂SnO₃·3H₂Dissolving O in 40 mL of deionized water, and magnetically stirring until all the O is dissolved; adding 8 mL of glycerol, and magnetically stirring at normal temperature for 20 min; transferring the solution into a 100 mL high-pressure reaction kettle, placing the high-pressure reaction kettle in an electric heating air blowing drying oven at 180 ℃, reacting for 20 h, taking out the high-pressure reaction kettle, cooling to room temperature, taking out the polytetrafluoroethylene lining, pouring off supernatant, respectively centrifugally washing precipitates for 3 times by using distilled water and absolute ethyl alcohol, drying in the drying oven at 80 ℃ for 2.5 h, and taking out required powder. Placing the prepared powder in an alumina crucible tank, putting the alumina crucible tank into a muffle furnace to calcine for about 10 hours, and synthesizing nano SnO₂。

Example three:

nano SnO₂And (4) preparing. At room temperature, 1.0mmol of K₂SnO₃·3H₂Dissolving O in 40 mL of deionized water, and magnetically stirring until all the O is dissolved; then adding 10 mL of glycerol into the mixture, and magnetically stirring the mixture for 20 min at normal temperature; transferring the solution into a 100 mL high-pressure reaction kettle, placing the high-pressure reaction kettle in an electric heating air blowing drying oven at 180 ℃, reacting for 20 h, taking out the high-pressure reaction kettle, cooling to room temperature, taking out the polytetrafluoroethylene lining, pouring off supernatant, respectively centrifugally washing precipitates for 3 times by using distilled water and absolute ethyl alcohol, drying in the drying oven at 80 ℃ for 2.5 h, and taking out required powder. Placing the prepared powder in an alumina crucible tank, putting the alumina crucible tank into a muffle furnace to calcine for about 10 hours, and synthesizing nano SnO₂。

And (5) testing the gas sensitivity performance of the ethanol. Dispersing 10mg of a sample to be detected into 200 muL of water solution, uniformly dispersing by ultrasonic, taking 10 muL, dropwise adding the sample to the surface of a sensing device, naturally drying, and then loading the sample into a sensing test system for carrying out related gas sensing performance test. The total flow rate of gas was controlled by a gas flowmeter to be constant at 200 sscm (standard cubic center meter per minu)te, milliliters per minute in standard conditions), the current for the sensory test was 120 mA. Defining gas sensitivity as S =R _air/ R _gas(whereinR _airThe resistance value of the sensing material under air condition,R _gasresistance value of the sensing material under air condition), response timeT ₁The time required for the resistance change value of the sensing material to fall to 90% of the maximum difference value after the sensing gas enters, and the recovery timeT ₂The time required for the resistance change value of the sensing material to rise to 90% of the maximum difference value after the sensing gas is turned off.

Example four:

nano SnO₂And (4) preparing. Under the condition of room temperature, adding 1.0mmol K₂SnO₃·3H₂Dissolving O in 40 mL of deionized water, and magnetically stirring until all the O is dissolved; then adding 10 mL of glycerol into the mixture, and magnetically stirring the mixture for 20 min at normal temperature; transferring the solution into a 100 mL high-pressure reaction kettle, placing the high-pressure reaction kettle in an electric heating air blowing drying oven at 180 ℃, reacting for 20 h, taking out the high-pressure reaction kettle, cooling to room temperature, taking out the polytetrafluoroethylene lining, pouring off supernatant, respectively centrifugally washing precipitates for 3 times by using distilled water and absolute ethyl alcohol, drying in the drying oven at 80 ℃ for 2.5 h, and taking out required powder. Placing the prepared powder in an alumina crucible tank, putting the alumina crucible tank into a muffle furnace to calcine for about 10 hours, and synthesizing nano SnO₂。

And (3) testing the gas sensitivity performance of the n-butyl alcohol. Dispersing 10mg of a sample to be detected into 200 muL of water solution, uniformly dispersing by ultrasonic, taking 10 muL, dropwise adding the sample to the surface of a sensing device, naturally drying, and then loading the sample into a sensing test system for carrying out related gas sensing performance test. The total gas flow rate was controlled by a gas flow meter to be constant at 200 sscm (standard cubic meter per minute) and the current for the sensor test was 120 mA. Defining gas sensitivity as S =R _air/ R _gas(whereinR _airThe resistance value of the sensing material under air condition,R _gasresistance value of the sensing material under air condition), response timeT ₁After the sensing gas enters, the resistance change value of the sensing material is reduced to the maximumTime required for 90% of difference, recovery timeT ₂The time required for the resistance change value of the sensing material to rise to 90% of the maximum difference value after the sensing gas is turned off.