阅读说明：本技术 一种酒精传感器及其制备方法 (Alcohol sensor and preparation method thereof ) 是由 陈忠伟 余爱萍 毛治宇 张益宁 于 2018-06-16 设计创作，主要内容包括：本发明公开了一种酒精传感器,其包含用作电解质膜的酸修饰的氧化石墨烯膜,所述酸修饰的氧化石墨烯膜的厚度为3～10μm,所述酸修饰的氧化石墨烯膜的内部分布有设定的孔隙结构,且孔隙的平均直径为40～80nm。其中所述酸为对氨基苯磺酸。本发明公开的酒精传感器可靠性好和灵敏度高,并且消除了现有的强酸电解质的潜在安全隐患,具有广泛的应用前景。(The invention discloses an alcohol sensor, which comprises an acid-modified graphene oxide film used as an electrolyte film, wherein the thickness of the acid-modified graphene oxide film is 3-10 mu m, a set pore structure is distributed in the acid-modified graphene oxide film, and the average diameter of pores is 40-80 nm. Wherein the acid is sulfanilic acid. The alcohol sensor disclosed by the invention has good reliability and high sensitivity, eliminates the potential safety hazard of the existing strong acid electrolyte, and has wide application prospect.)

1. An alcohol sensor comprising an acid-modified graphene oxide film used as an electrolyte membrane, the acid-modified graphene oxide film having a thickness of 3 to 10 μm, the acid-modified graphene oxide film having a pore structure defined therein, and pores having an average diameter of 40 to 80 nm.

2. The alcohol sensor according to claim 1, wherein the acid is sulfanilic acid.

3. A method of making an alcohol sensor according to claim 1 or 2, the method comprising the steps of, in order:

(1) preparing a graphene oxide dispersion liquid;

(2) under the ultrasonic condition, introducing ozone into the graphene oxide dispersion liquid obtained in the step (1) for 0.5-4 hours to obtain a porous graphene oxide dispersion liquid;

(3) adding sulfanilic acid and sodium hydroxide into the porous graphene oxide dispersion liquid obtained in the step (2), mixing, heating to 70-90 ℃, keeping reacting for 3-12 hours, then sequentially centrifuging and washing to remove residues, and finally exchanging residual metal ions into protons to obtain acid-modified graphene oxide;

(4) dispersing the obtained acid-modified graphene oxide in deionized water, and performing vacuum filtration to obtain an acid-modified graphene oxide film;

(5) and assembling the obtained acid-modified graphene oxide membrane and a commercial fuel cell electrode into an alcohol sensor.

4. The method according to claim 3, wherein in the step (1), the graphene oxide dispersion liquid is prepared by the following steps in sequence:

a. taking a certain amount of graphite powder and sodium nitrate, adding concentrated sulfuric acid, and uniformly mixing;

b. adding potassium permanganate into the mixture obtained in the step a to react for 1-8 h, and keeping the temperature of the whole reaction system not higher than 20 ℃ in the reaction period;

c. after the temperature of the reaction system in the step b is restored to the room temperature, adding deionized water into the reaction system for reaction for 0.5-2 h, then continuously adding the same amount of deionized water for dilution, then adding a certain amount of hydrogen peroxide until the reaction system changes color, and finally cooling to the room temperature;

d. and c, adding dilute hydrochloric acid into the reaction system obtained after the reaction in the step c for dilution, then sequentially filtering, washing and removing acid until the pH value of the reaction system is about 2, and finally diluting with deionized water to obtain the graphene oxide dispersion liquid.

5. The method of claim 4, wherein in step a, the particle size D of the graphite powder₅₀1 to 15 μm.

6. The method according to claim 4, wherein in the step a, the graphite powder, the sodium nitrate and the concentrated sulfuric acid are mixed according to a mass ratio of 2: (0.5-1.5): (40-50) in an amount.

7. The method according to claim 4, wherein in the step b, the potassium permanganate is mixed according to a mass ratio of potassium permanganate to graphite powder of (2-5): 1 is added.

8. The method according to claim 4, wherein in the step c, the deionized water is mixed with concentrated sulfuric acid according to a volume ratio of the deionized water to the concentrated sulfuric acid of (3-4): 1 is added.

9. The method according to claim 4, wherein in the step c, the hydrogen peroxide concentration is 30% according to the mass ratio of hydrogen peroxide to graphite (15-25): 1 is added.

10. The method according to claim 4, wherein in the step d, the concentration of the hydrochloric acid is 5%, and the volume ratio of the hydrochloric acid to the concentrated sulfuric acid is (35-45): 1 is added.

11. The method according to claim 3, wherein in the step (1), the graphene oxide dispersion liquid is diluted to have a concentration of 1-10 mg/mL.

12. The method according to claim 3, wherein in the step (3), the graphene oxide dispersion liquid, sulfanilic acid and sodium hydroxide are mixed according to a mass ratio of 4: (4-20) and (1-5).

13. The method according to claim 3, wherein in the step (4), the acid-modified graphene oxide and deionized water are added in a mass ratio of 1 (1-2).

Technical Field

The invention relates to the technical field of sensors, in particular to an alcohol sensor and a preparation method thereof.

Background

Alcohol sensors are generally test tools used to detect whether and how much alcohol a person consumes. The device can be used as a detection tool for detecting the drinking amount of a drinker when the traffic police enforces the law, so that the occurrence of serious traffic accidents is effectively reduced; the alcohol content in the exhaled gas of the human body can be detected in other occasions, so that the serious loss of casualties and property is avoided, and enterprises who are forbidden to go on duty after drinking in some high-risk fields.

In various countries, with the increasing consumption of alcohol drinks by residents and the frequent occurrence of various traffic accidents caused by drunk driving, alcohol concentration detection instruments play an unprecedented important role in traffic management and resident daily life. In recent years, the development of material technology has promoted the continuous improvement of the related technology of the alcohol detector. Among them, the discovery of graphene oxide materials has attracted global attention. The unique two-dimensional structure of the graphene oxide membrane also endows the graphene oxide membrane with typical anisotropic transport properties including thermal conductivity, electronic conductivity, water permeability and the like, and the graphene oxide membrane serving as a membrane separation material is successfully applied to various important fields.

The ionic conductivity of graphene oxide, mainly proton conductivity and hydroxide ion conductivity, has also been found to be anisotropic, and when used in some practical electrochemical devices, such as fuel cells, its anisotropic ion conductivity properties are not ideal. The fabrication of graphene oxide in porous form is an important strategy to address the proton conducting channels in this application. For example, patent nos: CN106596654A discloses a vertical response type gas sensor based on a three-dimensional porous graphene ultrathin film and a preparation method thereof, wherein a porous graphene dispersion liquid is obtained by carrying out dialysis treatment on a graphene oxide dispersion liquid after ultraviolet treatment. Patent No: CN106290489A discloses a porous graphene gas sensor and a preparation method thereof, which adopts a high-power ultraviolet radiation method and is sensitive to ammonia molecules. The method of the above patent is relatively complicated in process, and the ultraviolet irradiation has a certain damage to human body. As another example. Patent No: CN106430156A discloses preparation of porous graphene, porous graphene obtained therefrom and application thereof, and the method and the obtained porous graphene and application thereof are different from those of the present invention. Patent No: CN104752703A discloses a porous graphene, which is different from the method and application of the present invention.

Based on the currently used pore-forming methods, such as ultraviolet radiation, plasma etching, and the like, process control is complex. In addition, the traditional alcohol sensor still has the problems of strong corrosive strong acid liquid electrolyte leakage, slow response time, poor reliability and the like. Therefore, there is a need to develop a new graphene oxide material with excellent proton conductivity, which can enhance the reliability and sensitivity of the sensor when used in an alcohol sensor, and eliminate the potential safety hazard of a strong acid electrolyte.

Disclosure of Invention

The invention provides an alcohol sensor and a preparation method thereof aiming at the defects in the prior art, wherein the alcohol sensor comprises an acid modified graphene oxide film, the material is prepared by carrying out porous and acidification treatment on graphene oxide through ozone and sulfanilic acid, and the graphene oxide film has excellent proton conductivity when being used as an electrolyte film.

The purpose of the invention and the technical problem to be solved are realized by adopting the following technical scheme:

the alcohol sensor comprises an acid-modified graphene oxide film used as an electrolyte film, wherein the thickness of the acid-modified graphene oxide film is 3-10 mu m, a set pore structure is distributed in the acid-modified graphene oxide film, and the average diameter of pores is about 40-80 nm.

The alcohol sensor as described above, wherein the acid is sulfanilic acid.

The purpose of the invention and the technical problem to be solved can also be realized by adopting the following technical scheme:

according to the method of the alcohol sensor provided by the invention, the method sequentially comprises the following steps:

(1) preparing a graphene oxide dispersion liquid;

(2) under the ultrasonic condition, introducing ozone into the graphene oxide dispersion liquid obtained in the step (1) for 0.5-4 hours to obtain a porous graphene oxide dispersion liquid;

(3) adding sulfanilic acid and sodium hydroxide into the porous graphene oxide dispersion liquid obtained in the step (2), mixing, heating to 70-90 ℃, keeping reacting for 3-12 hours, then sequentially centrifuging and washing to remove residues, and finally exchanging residual metal ions into protons to obtain acid-modified graphene oxide;

(4) dispersing the obtained acid-modified graphene oxide in deionized water, and performing vacuum filtration to obtain an acid-modified graphene oxide film;

(5) and assembling the obtained acid-modified graphene oxide membrane and a commercial fuel cell electrode into an alcohol sensor.

In the method, in the step (1), the graphene oxide dispersion liquid is prepared through the following steps in sequence:

a. taking a certain amount of graphite powder and sodium nitrate, adding concentrated sulfuric acid, and uniformly mixing;

b. adding potassium permanganate into the mixture obtained in the step a to react for 1-8 h, and keeping the temperature of the whole reaction system not higher than 20 ℃ in the reaction period;

c. after the temperature of the reaction system in the step b is restored to the room temperature, adding deionized water into the reaction system for reaction for 0.5-2 h, then continuously adding the same amount of deionized water for dilution, then adding a certain amount of hydrogen peroxide until the reaction system changes color, and finally cooling to the room temperature;

d. and c, adding dilute hydrochloric acid into the reaction system obtained after the reaction in the step c for dilution, then sequentially filtering, washing and removing acid until the pH value of the reaction system is about 2, and finally diluting with deionized water to obtain the graphene oxide dispersion liquid.

The method, wherein in the step a, the particle size D of the graphite powder₅₀1 to 15 μm.

In the method, in the step a, the graphite powder, the sodium nitrate and the concentrated sulfuric acid are mixed according to a mass ratio of 2: (0.5-1.5): (40-50) in an amount.

In the method, in the step b, the mass ratio of the potassium permanganate to the graphite powder is (2-5): 1 is added.

In the method, in the step c, the volume ratio of the deionized water to the concentrated sulfuric acid is (3-4): 1 is added.

In the method, in the step c, the hydrogen peroxide concentration is 30%, and the mass ratio of hydrogen peroxide to graphite is (15-25): 1 is added.

In the method, in the step d, the concentration of the hydrochloric acid is 5%, and the volume ratio of the hydrochloric acid to the concentrated sulfuric acid is (35-45): 1 is added.

In the method, in the step (1), the graphene oxide dispersion liquid has a dilution concentration of 1-10 mg/mL.

The method, wherein in the step (3), the ratio of the graphene oxide dispersion liquid to sulfanilic acid to sodium hydroxide is 4: (4-20) and (1-5).

In the method, in the step (4), the acid-modified graphene oxide and deionized water are added according to a mass ratio of 1 (1-2).

The invention has the beneficial effects that:

(1) the alcohol sensor adopts the acid modified graphene oxide film as the electrolyte film, wherein the acid modified graphene oxide film is prepared into porous graphene oxide by ozone treatment, and compared with ultraviolet light or plasma etching and the like used in the prior art, the method is simple and effective. And the sulfanilic acid is simply and effectively treated to introduce sulfonic acid groups into the porous graphene oxide nano-sheets, so that the proton conductivity of the membrane can be remarkably improved.

(2) The novel graphene oxide-based solid proton conductor is applied to the alcohol sensor, so that leakage of strong corrosive strong acid liquid electrolyte in the traditional alcohol sensor is effectively reduced, attenuation of corresponding signals is reduced, reliability of the sensor is enhanced, and potential safety hazards of the strong acid electrolyte are eliminated.

(3) The alcohol sensor disclosed by the invention is simple and effective in manufacturing process, is suitable for industrial production, and has a wide application prospect.

Drawings

Fig. 1 is a TEM image of an acid-modified graphene oxide film obtained according to the preparation method in example 1 of the present invention;

fig. 2 is an SEM image of the acid-modified graphene oxide film obtained according to the preparation method in example 1 of the present invention;

fig. 3 is a graph showing a relationship between proton conductivity and temperature of the acid-modified graphene oxide film obtained by the preparation method in example 1 of the present invention;

FIG. 4 is a response curve of the alcohol sensor obtained according to the manufacturing method of examples 1, 2, 3, 4 of the present invention, wherein a, b, c and d represent response curves of the alcohol sensor in example 1, example 2, example 3 and example 4, respectively;

fig. 5 is a response curve of the alcohol sensor according to the manufacturing method of example 1 of the present invention and comparative example 1.

Detailed Description

The present invention is further illustrated by the following figures and examples, which are to be understood as merely illustrative and not restrictive. Furthermore, it should be understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the teachings herein, and such equivalents may fall within the scope of the invention as defined in the appended claims.