阅读说明：本技术 一种球状三氧化钼-氧化锌纳米复合物的制备方法及其应用 (Preparation method and application of spherical molybdenum trioxide-zinc oxide nano compound ) 是由 王宏归 潘华伟 张娅 于 2020-04-28 设计创作，主要内容包括：本发明涉及一种球状三氧化钼-氧化锌纳米复合物的制备方法及其应用,包括如下步骤：分别称取二水合醋酸锌和尿素于去离子水中并搅拌；再加入柠檬酸钠并搅拌一定时间,转移至高压反应釜中反应；离心分离后用乙醇和去离子水清洗并烘干,得到碱式碳酸锌；完全混合四水合钼酸铵和碱式碳酸锌,然后放置于管式炉中煅烧得到球状三氧化钼-氧化锌纳米复合物；取球状三氧化钼-氧化锌纳米复合物分散在水、乙醇及全氟磺酸的混合液中,滴涂在清洁的玻碳电极表面；自然风干后作为工作电极与铂丝及饱和甘汞电极组成三电极体系。结果证明该球状三氧化钼-氧化锌纳米复合物检测过氧化氢操作简单,灵敏度高,检测浓度范围宽。(The invention relates to a preparation method and application of a spherical molybdenum trioxide-zinc oxide nano compound, which comprises the following steps: respectively weighing zinc acetate dihydrate and urea in deionized water and stirring; adding sodium citrate, stirring for a certain time, and transferring to a high-pressure reaction kettle for reaction; after centrifugal separation, washing with ethanol and deionized water and drying to obtain basic zinc carbonate; completely mixing ammonium molybdate tetrahydrate and basic zinc carbonate, and then placing the mixture into a tube furnace to calcine the mixture to obtain a spherical molybdenum trioxide-zinc oxide nano compound; dispersing a spherical molybdenum trioxide-zinc oxide nano compound in a mixed solution of water, ethanol and perfluorosulfonic acid, and dripping the mixed solution on the surface of a clean glassy carbon electrode; after natural air drying, the electrode is used as a working electrode to form a three-electrode system together with a platinum wire and a saturated calomel electrode. The result proves that the spherical molybdenum trioxide-zinc oxide nano composite is simple to operate, high in sensitivity and wide in detection concentration range when used for detecting hydrogen peroxide.)

1. A preparation method of spherical molybdenum trioxide-zinc oxide nano compound is characterized by comprising the following steps: the method comprises the following steps:

(1) respectively weighing 0.1-10 g of zinc acetate dihydrate and 0.1-10 g of urea in deionized water, and uniformly stirring to obtain a first mixed solution;

(2) weighing 10-500 mg of sodium citrate, adding the sodium citrate into the first mixed solution obtained in the step (1), and stirring for 20-40 minutes to obtain a second mixed solution;

(3) transferring the second mixed solution obtained in the step (2) to a high-pressure reaction kettle, and reacting at 100-200 ℃ to obtain a reactant;

(4) after centrifugally separating the reaction product obtained in the step (3) to remove water, firstly cleaning the reaction product with ethanol to remove unreacted organic matters, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, and placing the cleaned reaction product in a drying oven to be dried at the temperature of 60-90 ℃ to obtain basic zinc carbonate;

(5) respectively weighing 0.1-10 g of ammonium molybdate tetrahydrate and 50-500 mg of the basic zinc carbonate obtained in the step (4), mixing, and grinding until complete mixing to obtain a mixture;

(6) and (3) placing the mixture obtained in the step (5) in a tube furnace, and calcining for 1-4 h at 200-500 ℃ to obtain the spherical molybdenum trioxide-zinc oxide nano composite.

2. The preparation method of the spherical molybdenum trioxide-zinc oxide nano composite according to claim 1, which is characterized by comprising the following steps: in the step (1), the volume of the deionized water is 0.01-0.2 liter.

3. The preparation method of the spherical molybdenum trioxide-zinc oxide nano composite according to claim 1, which is characterized by comprising the following steps: in the step (3), the reaction time is 2-12 hours.

4. The preparation method of the spherical molybdenum trioxide-zinc oxide nano composite according to claim 1, which is characterized by comprising the following steps: in the step (4), the centrifugation speed is 3000-6000 rpm, and the drying time is 12-24 hours.

5. The application method of the spherical molybdenum trioxide-zinc oxide nano compound modified glassy carbon electrode prepared by the preparation method of the spherical molybdenum trioxide-zinc oxide nano compound in the claim 1 in detecting hydrogen peroxide in water is characterized in that: the operation process of detection is as follows:

a) weighing 3-8 mg of spherical molybdenum trioxide-zinc oxide nano compound and perfluorosulfonic acid, adding the spherical molybdenum trioxide-zinc oxide nano compound and perfluorosulfonic acid into a mixed solution of deionized water and ethanol, and ultrasonically mixing uniformly to obtain a uniform mixed solution;

b) dripping the uniform mixed liquid obtained in the step a) on the surface of a clean glassy carbon electrode, and drying at room temperature;

c) forming a three-electrode system by the glassy carbon electrode treated in the step b), a platinum wire and a saturated calomel electrode;

d) putting the three-electrode system into hydrogen peroxide solution containing hydrogen peroxide with different concentrations, and determining the catalytic performance of the spherical molybdenum trioxide-zinc oxide on the hydrogen peroxide by cyclic voltammetry;

e) placing the three-electrode system into a phosphoric acid buffer solution with constant concentration, dropwise adding hydrogen peroxide solutions with different concentrations, respectively measuring response current values corresponding to the hydrogen peroxide solutions with different concentrations by a potentiostatic method, and preparing a linear relation graph of the hydrogen peroxide concentration and the response current;

f) and obtaining the concentration value of the hydrogen peroxide in the phosphoric acid buffer solution to be detected by using the linear relation chart prepared by using the phosphoric acid buffer solution with the same hydrogen peroxide concentration as that in the step e).

6. The method of application according to claim 5, characterized in that: in the step a), the volume ratio of the deionized water to the ethanol is 3: 1-6: 1, and keeping the total volume of the mixed liquid of the spherical molybdenum trioxide-zinc oxide nano compound, the perfluorinated sulfonic acid, the deionized water and the ethanol to be 0.8-1.2 ml.

7. The method of application according to claim 5, characterized in that: in the step b), the volume of the dripping mixed solution is 3-15 microliters.

8. The method of application according to claim 5, characterized in that: in the step d), the potential range of the cyclic voltammetry is-1.4-0.4V.

Technical Field

The invention relates to a preparation method and application of a spherical molybdenum trioxide-zinc oxide nano compound, belonging to the technical field of environmental detection.

Background

Hydrogen peroxide is colorless transparent liquid, has strong oxidizing property and bactericidal property, is widely applied to industries such as medicine, industry, food, beauty treatment and the like, is a common disinfectant and oxidant, is indispensable in the fields such as industry and the like, but the abuse of hydrogen peroxide can harm aquatic organisms in the environment and the health of human bodies, can cause gene mutation of human bodies, and can accelerate human body aging and arteriosclerosis; therefore, real-time detection of hydrogen peroxide is a very necessary and meaningful thing in environmental control. The electrochemical method is one of the common methods for detecting hydrogen peroxide, is an environment-friendly and convenient technology, and has the advantages of quick response, high sensitivity, simple operation and the like compared with a fluorescence spectrophotometry method, a chemiluminescence method and a colorimetric method. However, this method is not particularly desirable due to the complex synthesis of the materials used to modify the electrodes and the adhesion. One solution to this problem is to select efficient and economical nanocomposite modified electrodes.

As is well known, nano zinc oxide is an electrode modification material with better electrocatalytic properties and is easy to synthesize. However, the common monomer zinc oxide has lower activity and smaller specific surface area. One strategy for solving the problem is to change the appearance and structure of the zinc oxide and compound the zinc oxide with other high-activity nano materials to prepare the nano composite material with high specific surface area and high electrocatalytic activity. Molybdenum trioxide as a catalytic material which is relatively popular at present has high photoelectric activity, and is widely applied to the fields of photocatalysis, electrocatalysis and the like. Therefore, the spherical molybdenum trioxide-zinc oxide nano compound is prepared to modify the electrode, so that the electrochemical performance of the material can be effectively improved, and the hydrogen peroxide can be detected quickly and efficiently in real time.

Disclosure of Invention

The invention aims to provide a preparation method and application of a spherical molybdenum trioxide-zinc oxide nano composite aiming at the problems in the prior art.

The invention aims to realize the purpose, and the preparation method of the spherical molybdenum trioxide-zinc oxide nano compound is characterized by comprising the following steps: the method comprises the following steps:

(1) respectively weighing 0.1-10 g of zinc acetate dihydrate and 0.1-10 g of urea in deionized water, and uniformly stirring to obtain a first mixed solution;

(2) weighing 10-500 mg of sodium citrate, adding the sodium citrate into the first mixed solution obtained in the step (1), and stirring for 20-40 minutes to obtain a second mixed solution;

(3) transferring the second mixed solution obtained in the step (2) to a high-pressure reaction kettle, and reacting at 100-200 ℃ to obtain a reactant;

(4) after centrifugally separating the reaction product obtained in the step (3) to remove water, firstly cleaning the reaction product with ethanol to remove unreacted organic matters, then cleaning the reaction product with deionized water to remove unreacted inorganic ions, and placing the cleaned reaction product in a drying oven to be dried at the temperature of 60-90 ℃ to obtain basic zinc carbonate;

(5) respectively weighing 0.1-10 g of ammonium molybdate tetrahydrate and 50-500 mg of the basic zinc carbonate obtained in the step (4), mixing, and grinding until complete mixing to obtain a mixture;

(6) and (3) placing the mixture obtained in the step (5) in a tube furnace, and calcining for 1-4 h at 200-500 ℃ to obtain the spherical molybdenum trioxide-zinc oxide nano composite.

In the step (1), the volume of the deionized water is 0.01-0.2 liter.

In the step (3), the reaction time is 2-12 hours.

In the step (4), the centrifugation speed is 3000-6000 rpm, and the drying time is 12-24 hours.

An application method of a glassy carbon electrode modified by a spherical molybdenum trioxide-zinc oxide nano compound prepared by a preparation method of the spherical molybdenum trioxide-zinc oxide nano compound in detection of hydrogen peroxide in water is characterized by comprising the following steps: the operation process of detection is as follows:

a) weighing 3-8 mg of spherical molybdenum trioxide-zinc oxide nano compound and perfluorosulfonic acid, adding the spherical molybdenum trioxide-zinc oxide nano compound and perfluorosulfonic acid into a mixed solution of deionized water and ethanol, and ultrasonically mixing uniformly to obtain a uniform mixed solution;

b) dripping the uniform mixed liquid obtained in the step a) on the surface of a clean glassy carbon electrode, and drying at room temperature;

c) forming a three-electrode system by the glassy carbon electrode treated in the step b), a platinum wire and a saturated calomel electrode;

d) putting the three-electrode system into hydrogen peroxide solution containing hydrogen peroxide with different concentrations, and determining the catalytic performance of the spherical molybdenum trioxide-zinc oxide on the hydrogen peroxide by cyclic voltammetry;

e) placing the three-electrode system into a phosphoric acid buffer solution with constant concentration, dropwise adding hydrogen peroxide solutions with different concentrations, respectively measuring response current values corresponding to the hydrogen peroxide solutions with different concentrations by a potentiostatic method, and preparing a linear relation graph of the hydrogen peroxide concentration and the response current;

f) and obtaining the concentration value of the hydrogen peroxide in the phosphoric acid buffer solution to be detected by using the linear relation chart prepared by using the phosphoric acid buffer solution with the same hydrogen peroxide concentration as that in the step e).

In the step a), the volume ratio of the deionized water to the ethanol is 3: 1-6: 1, and keeping the total volume of the mixed liquid of the spherical molybdenum trioxide-zinc oxide nano compound, the perfluorinated sulfonic acid, the deionized water and the ethanol to be 0.8-1.2 ml.

In the step b), the volume of the dripping mixed solution is 3-15 microliters.

In the step d), the potential range of the cyclic voltammetry is-1.4-0.4V.

The preparation method and the application of the spherical molybdenum trioxide-zinc oxide nano compound provided by the invention have the advantages that the preparation method of the spherical molybdenum trioxide-zinc oxide nano compound comprises the following steps:

(1) the preparation method comprises the steps of (1) weighing 0.1-10 g of zinc acetate dihydrate and 0.1-10 g of urea in deionized water, uniformly stirring, (2) weighing 10-500 mg of sodium citrate, adding the sodium citrate into the mixed liquid obtained in the step ⑴, stirring for 20-40 minutes, (3) transferring the mixed liquid obtained in the step (2) into a high-pressure reaction kettle, reacting at 100-200 ℃, (4) after centrifugally separating and removing moisture from the reaction product obtained in the step (3), cleaning and removing unreacted organic matters by using ethanol, cleaning and removing unreacted inorganic ions by using deionized water, placing the cleaned reaction product into an oven, drying at 60-90 ℃ to obtain basic zinc carbonate, (5) weighing 0.1-10 g of ammonium tetrahydrate and a proper amount of the product obtained in the step (4), mixing, grinding until the mixture is completely mixed, (6) placing the mixture obtained in the step (5) into a tubular furnace, calcining at 200-500 ℃ for 1-4 hours to obtain a spherical molybdenum trioxide-zinc oxide nano compound, wherein the volume of the deionized water in the step (1) is 0.01-0.2 liter, the reaction time in the step (3), and the reaction time in the step (5) is 3000-3000 hours, and the step (5) is carried out the step (5).

The invention also aims to provide an application method of the spherical molybdenum trioxide-zinc oxide nano composite in detecting the content of hydrogen peroxide in water. The operation process of detection is as follows:

a) weighing 3-8 mg of molybdenum trioxide-zinc oxide nano compound and perfluorosulfonic acid, adding the molybdenum trioxide-zinc oxide nano compound and perfluorosulfonic acid into a mixed solution of deionized water and ethanol, and ultrasonically mixing uniformly; b) dropping a proper amount of the uniform mixed liquid obtained in the step a) on the surface of a clean glassy carbon electrode, and drying at room temperature; c) forming a three-electrode system by the glassy carbon electrode obtained in the step b), a platinum wire and a saturated calomel electrode; d) putting the three-electrode system into hydrogen peroxide solution containing hydrogen peroxide with different concentrations, and determining the catalytic performance of the spherical molybdenum trioxide-zinc oxide compound on the hydrogen peroxide by using a cyclic voltammetry method; e) putting the three-electrode system into a phosphoric acid buffer solution with constant concentration, dropwise adding hydrogen peroxide solutions with different concentrations, respectively measuring response current values corresponding to the hydrogen peroxide solutions with different concentrations by a potentiostatic method, and preparing a linear relation graph of the hydrogen peroxide concentration and the response current; f) and obtaining the concentration value of the hydrogen peroxide in the phosphoric acid buffer solution to be detected by using the linear relation chart prepared by using the phosphoric acid buffer solution with the same hydrogen peroxide concentration as that in the step e). Wherein the volume ratio of the deionized water to the ethanol in the step a) is 3: 1-6: 1, and keeping the total volume of the mixed liquid of the compound, the perfluorinated sulfonic acid, the deionized water and the ethanol within 0.8-1.2 ml. The volume of the mixed solution dripped in the step b) is 3-15 microliters. The potential range of the cyclic voltammetry in the step d) is-1.4-0.4V. The potential range of the potentiostatic method in the step e) is-1.0-0V.

Compared with the prior art, the invention has the following beneficial effects:

1. the quality of the sodium citrate added in the step (2) cannot be too high or too low, so that the basic zinc carbonate with better shape and size can be obtained under control, and the electrocatalytic performance is higher.

2. And (3) sealing the mixed solution in the step (3) in a high-pressure reaction kettle, generating high pressure in the reaction kettle along with the temperature rise to 100-200 ℃, fully dispersing zinc acetate dihydrate and urea in the aqueous solution in a high-temperature and high-pressure physical environment, and reacting for 2-12 hours to obtain uniformly dispersed basic zinc carbonate.

3. Too high or too low quality of the basic zinc carbonate added in the step (5) is not favorable for obtaining the spherical molybdenum trioxide-zinc oxide nano compound with good dispersion and catalytic performance.

4. And (6) placing the mixture into a tubular furnace, and with the temperature rising to 200-500 ℃, fully mixing ammonium molybdate tetrahydrate with basic zinc carbonate in a high-temperature physical environment, and reacting for 1-4 hours to generate molybdenum trioxide-zinc oxide with better appearance and structure, so as to form a spherical molybdenum trioxide-zinc oxide nano compound with high activity.

Molybdenum trioxide in the spherical molybdenum trioxide-zinc oxide nano compound prepared by the invention: the weight ratio of the zinc oxide is (1-10): 1, and the zinc oxide has excellent performance of electrocatalysis of hydrogen peroxide in water, and is simple to synthesize and low in cost. At 0.1 mol^-3The concentration range of the hydrogen peroxide capable of being detected in the phosphoric acid buffer solution is 4-3800 mu mol dm^-3。

To sum up, the invention relates to preparation and application of a spherical molybdenum trioxide-zinc oxide nano compound, which comprises the following steps: respectively weighing zinc acetate dihydrate and urea in deionized water and stirring; adding sodium citrate, stirring for a certain time, and transferring to a high-pressure reaction kettle for reaction; after centrifugal separation, washing with ethanol and deionized water and drying to obtain basic zinc carbonate; completely mixing ammonium molybdate tetrahydrate and basic zinc carbonate, and then placing the mixture into a tube furnace to calcine the mixture to obtain a spherical molybdenum trioxide-zinc oxide nano compound; dispersing a spherical molybdenum trioxide-zinc oxide nano compound in a mixed solution of water, ethanol and perfluorosulfonic acid, and dripping the mixed solution on the surface of a clean glassy carbon electrode; after natural air drying, the electrode is used as a working electrode to form a three-electrode system together with a platinum wire and a saturated calomel electrode. The result proves that the spherical molybdenum trioxide-zinc oxide nano composite is simple to operate, high in sensitivity and wide in detection concentration range when used for detecting hydrogen peroxide.

Drawings

FIG. 1 is a scanning electron micrograph of a spherical molybdenum trioxide-zinc oxide composite of example 1 of the present invention.

FIG. 2 is a cyclic voltammogram of the spherical molybdenum trioxide-zinc oxide composite of example 2 of the present invention in a phosphoric acid buffer solution containing no (solid line) and hydrogen peroxide (dotted line).

Fig. 3 is an ampere response curve of the spherical molybdenum trioxide-zinc oxide compound modified electrode related to the invention.

FIG. 4 is a graph of hydrogen peroxide concentration versus response current according to the present invention.

Detailed Description

The invention will be described in further detail with reference to the following drawings and detailed description, which are provided for reference and illustration purposes only and are not intended to limit the invention.

The preparation of the spherical molybdenum trioxide-zinc oxide compound and the modified glassy carbon electrode thereof is further illustrated by combining specific examples.