阅读说明：本技术 多孔锡酸镉材料、其合成方法及硫化氢预警传感器 (Porous cadmium stannate material, synthesis method thereof and hydrogen sulfide early warning sensor ) 是由 孙鉴波 张海雪 于 2019-11-27 设计创作，主要内容包括：本发明公开了一种多孔锡酸镉材料、其合成方法及硫化氢预警传感器,属于传感器技术领域。该多孔锡酸镉材料的合成方法包括以下步骤：将乙酸镉溶液和聚乙烯吡咯烷酮溶液同时缓慢地加入到四氯化锡溶液中,并进行搅拌,得到第一混合液；将第一混合液的pH值调至12～14,得到第二混合液；将第二混合液置于70～90℃的条件下进行搅拌反应后,再进行离心收集,得到沉淀物；将沉淀物进行洗涤、干燥后,再置于600～800℃的条件下进行热处理,得到所述的多孔锡酸镉材料。该多孔锡酸镉材料具有结晶度高、氧空位多、比表面积大等特点,其有益于提升气敏性能；利用该多孔锡酸镉材料制得的硫化氢硫化氢预警传感器能够实现快速的响应恢复,具有高灵敏度的特点。(The invention discloses a porous cadmium stannate material, a synthesis method thereof and a hydrogen sulfide early warning sensor, and belongs to the technical field of sensors. The synthesis method of the porous cadmium stannate material comprises the following steps: slowly adding the cadmium acetate solution and the polyvinylpyrrolidone solution into the stannic chloride solution at the same time, and stirring to obtain a first mixed solution; adjusting the pH value of the first mixed solution to 12-14 to obtain a second mixed solution; stirring the second mixed solution at 70-90 ℃ for reaction, and then carrying out centrifugal collection to obtain a precipitate; and washing and drying the precipitate, and then performing heat treatment at 600-800 ℃ to obtain the porous cadmium stannate material. The porous cadmium stannate material has the characteristics of high crystallinity, more oxygen vacancies, large specific surface area and the like, and is beneficial to improving the gas-sensitive performance; the hydrogen sulfide and hydrogen sulfide early warning sensor prepared from the porous cadmium stannate material can realize quick response recovery and has the characteristic of high sensitivity.)

1. A method for synthesizing a porous cadmium stannate material is characterized by comprising the following steps:

weighing cadmium acetate dihydrate, stannic chloride pentahydrate and polyvinylpyrrolidone for later use;

respectively dissolving cadmium acetate dihydrate, stannic chloride pentahydrate and polyvinylpyrrolidone in deionized water to obtain a cadmium acetate solution, a stannic chloride solution and a polyvinylpyrrolidone solution for later use;

slowly adding the cadmium acetate solution and the polyvinylpyrrolidone solution into the stannic chloride solution at the same time, and stirring to obtain a first mixed solution;

adjusting the pH value of the first mixed solution to 12-14 by adding an alkali solution to obtain a second mixed solution;

placing the second mixed solution in a water bath heating condition of 70-90 ℃ for stirring reaction, and then performing centrifugal collection to obtain a precipitate;

and washing and drying the precipitate, and then performing heat treatment at 600-800 ℃ to obtain the porous cadmium stannate material.

2. The method for synthesizing the porous cadmium stannate material according to claim 1, wherein the molar ratio of the cadmium acetate dihydrate to the tin tetrachloride pentahydrate is 1 (0.8-1.2); the mass ratio of the cadmium acetate dihydrate to the polyvinylpyrrolidone is 1 (1-2).

3. The method as claimed in claim 1, wherein in the step of washing and drying the precipitate, the precipitate is washed alternately with deionized water and absolute ethanol.

4. The method for synthesizing the porous cadmium stannate material according to claim 1, wherein the step of washing and drying the precipitate is performed at a temperature of 50-70 ℃.

5. A porous cadmium stannate material prepared by the synthesis method of any one of claims 1 to 4.

6. The porous cadmium stannate material of claim 5, wherein the specific surface area of the porous cadmium stannate material is 15-25 m²/g。

7. A hydrogen sulfide early warning sensor, which comprises a gas sensor, wherein the gas sensor comprises a base and a ceramic tube arranged on the base, and is characterized in that the ceramic tube is partially or completely coated with the porous cadmium stannate material of claim 5 or 6.

Technical Field

The invention relates to the technical field of sensors, in particular to a porous cadmium stannate material, a synthetic method thereof and a hydrogen sulfide early warning sensor.

Background

Hydrogen sulfide (H)₂S) is colorless toxic combustible gas and exists in crude oil, natural gas and volcano gas. Other sources in the industry include food processing, coke ovens, paper mills, tanneries, and oil refineries. It is known to be extremely harmful to both the human body and the environment. In addition, it affects the human nervous system and even at low concentrations can lead to deathDeath, the threshold limit of 10 ppm. Albeit human nose pair H₂The detection threshold for S is as low as 0.02ppm, but at H₂H before the S concentration reaches the dangerous threshold of 50-100 ppm₂The person with S poisoning cannot recognize the peculiar smelly of the rotten eggs. Thus, monitoring and controlling H₂The trace of S gas has become of paramount importance, namely for H, which is highly sensitive, highly selective, repeatable, low cost, easy to handle₂The research of the S sensor is an urgent need.

Although many reports have been made on the research of hydrogen sulfide early warning sensors, the metal oxide semiconductor hydrogen sulfide early warning sensor has the advantages of high chemical stability, low cost and the like, and is widely applied. However, the existing hydrogen sulfide early warning sensor has the problem of low detection sensitivity, and the existing hydrogen sulfide early warning sensor cannot meet the current requirements along with the continuous improvement of the requirements of people on the environmental quality.

Disclosure of Invention

An embodiment of the present invention provides a method for synthesizing a porous cadmium stannate material, so as to solve the problems in the background art.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

a method for synthesizing a porous cadmium stannate material comprises the following steps:

weighing cadmium acetate dihydrate, stannic chloride pentahydrate and polyvinylpyrrolidone for later use;

respectively dissolving cadmium acetate dihydrate, stannic chloride pentahydrate and polyvinylpyrrolidone in deionized water to obtain a cadmium acetate solution, a stannic chloride solution and a polyvinylpyrrolidone solution for later use;

slowly adding the cadmium acetate solution and the polyvinylpyrrolidone solution into the stannic chloride solution at the same time, and stirring to obtain a first mixed solution;

adjusting the pH value of the first mixed solution to 12-14 by adding an alkali solution to obtain a second mixed solution;

placing the second mixed solution in a water bath heating condition of 70-90 ℃ for stirring reaction, and then performing centrifugal collection to obtain a precipitate;

and washing and drying the precipitate, and then performing heat treatment at 600-800 ℃ to obtain the porous cadmium stannate material.

As a preferable scheme of the embodiment of the invention, the molar ratio of the cadmium acetate dihydrate to the tin tetrachloride pentahydrate is 1 (0.8-1.2); the mass ratio of the cadmium acetate dihydrate to the polyvinylpyrrolidone is 1 (1-2).

As another preferable embodiment of the present invention, in the step of washing and drying the precipitate, the precipitate is alternately washed with deionized water and absolute ethanol.

In another preferable embodiment of the present invention, in the step of washing and drying the precipitate, the drying temperature is 50 to 70 ℃.

Another object of the embodiments of the present invention is to provide a porous cadmium stannate material prepared by the above synthesis method.

As another preferable scheme of the embodiment of the invention, the specific surface area of the porous cadmium stannate material is 15-25 m²/g。

Another object of an embodiment of the present invention is to provide an application of the above porous cadmium stannate material in a hydrogen sulfide warning sensor.

Another objective of an embodiment of the present invention is to provide a hydrogen sulfide early warning sensor, which includes a gas sensor, where the gas sensor includes a base and a ceramic tube disposed on the base, and a part or all of the ceramic tube is coated with the above-mentioned porous cadmium stannate material.

Compared with the prior art, the embodiment of the invention has the beneficial effects that:

the porous cadmium stannate material prepared by the embodiment of the invention has the characteristics of high crystallinity, more oxygen vacancies, large specific surface area and the like, and is beneficial to improving the gas-sensitive performance. The hydrogen sulfide and hydrogen sulfide early warning sensor prepared from the porous cadmium stannate material can realize quick response recovery, can detect hydrogen sulfide with the concentration of 5ppm, and has the characteristic of high sensitivity. In addition, the synthesis method of the porous cadmium stannate material is simple, low in cost and easy to realize industrial mass production.

Drawings

Fig. 1 is a scanning electron microscope image of a porous cadmium stannate material provided in example 5 of the present invention.

FIG. 2 is an X-ray diffraction pattern of the porous cadmium stannate material and the standard substance provided in example 5 of the present invention.

Fig. 3 is a diagram showing the result of Cd element characterization performed on the porous cadmium stannate material provided in embodiment 5 of the present invention by an energy spectrometer.

Fig. 4 is a diagram illustrating a result of Sn element characterization of the porous cadmium stannate material provided in example 5 of the present invention by an energy spectrometer.

FIG. 5 shows the hydrogen sulfide pre-warning sensor pair at 50ppm H at different operating temperatures₂Sensitivity change profile of S.

FIG. 6 shows that hydrogen sulfide early warning sensor enters and exits 10ppm of H three times at 220 deg.C₂S response and recovery plots.

Fig. 7 reflects the sensitivity of the hydrogen sulfide pre-alarm sensor to various gases at 220 c.

FIG. 8 shows the hydrogen sulfide warning sensor for different concentrations of H at 220 deg.C₂Sensitivity change profile of S.

FIG. 9 shows N of a porous cadmium stannate material₂Adsorption-desorption isotherms and pore size distribution curves.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.