阅读说明：本技术 一种可见光催化剂的制备方法 (Preparation method of visible light catalyst ) 是由 丁凤 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种可见光催化剂的制备方法,通过共沉淀-水热的方法制备出热敏催化剂Ag-3PO-4/α-Bi-2O-3；首先是通过水热方法制备出α-Bi-2O-3,然后依次加入硝酸银和磷酸氢二钠,最后在α-Bi-2O-3表面共沉淀生成热敏催化剂Ag-3PO-4/α-Bi-2O-3；用亚甲基蓝和罗丹明B模拟有机物,降解率最高能达到99.9％；采用本发明的制备方法得到光催化剂Ag-3PO-4/α-Bi-2O-3具备高效、稳定和简单易得的优点以及可提高有机污染物的光催化降解效率。(The invention discloses a preparation method of a visible light catalyst, and a thermal sensitive catalyst Ag is prepared by a coprecipitation-hydrothermal method 3 PO 4 /α‑Bi 2 O 3 (ii) a Firstly, preparing alpha-Bi by a hydrothermal method 2 O 3 Then adding silver nitrate and disodium hydrogen phosphate in turn, and finally adding silver nitrate and disodium hydrogen phosphate into alpha-Bi 2 O 3 Surface coprecipitation to generate heat-sensitive catalyst Ag 3 PO 4 /α‑Bi 2 O 3 (ii) a Methylene blue and rhodamine B are used for simulating organic matters, and the highest degradation rate can reach 99.9%; the photocatalyst Ag is obtained by adopting the preparation method of the invention 3 PO 4 /α‑Bi 2 O 3 Has the advantages of high efficiency, stability, simplicity and easy obtainingAnd the photocatalytic degradation efficiency of organic pollutants can be improved.)

1. A preparation method of a visible light catalyst is characterized by comprising the following steps: the preparation method comprises the following steps:

step one, sequentially adding a certain amount of polyethylene glycol and a certain amount of sodium hydroxide solution into bismuth nitrate, adding ammonia water into the bismuth nitrate, and uniformly stirring;

step two, heating the precipitate generated in the step one for a period of time, cooling, taking out the powder, roasting and drying to obtain alpha-Bi₂O₃；

Step three, mixing alpha-Bi₂O₃Uniformly dispersing in deionized water, and ultrasonic treating to obtain alpha-Bi₂O₃Uniformly dispersing in water;

step four, dropwise adding silver nitrate, stirring to dissolve the silver nitrate, and then dropwise adding a disodium hydrogen phosphate solution to obtain a precipitate; heating the precipitate, naturally cooling, cleaning, and drying to obtain the target product Ag₃PO₄/α-Bi₂O₃。

2. The method for preparing a visible light catalyst according to claim 1, wherein: in the first step, ammonia water is used for adjusting the pH value of the solution to be within a range of 9-10.

3. The method for preparing a visible light catalyst according to claim 1, wherein: the sodium hydroxide solution in the first step is a sodium hydroxide solution without carbon dioxide.

4. According to claim1, the preparation method of the visible light catalyst is characterized by comprising the following steps: the Ag is₃PO₄And alpha-Bi₂O₃The molar ratio of (A) to (B) is 0.1:1 to 1: 1.

5. The method for preparing a visible light catalyst according to claim 1, wherein: transferring the generated precipitate into a hydrothermal reaction kettle, and continuously heating for 2-3 h at 90-110 ℃; taking out the powder after cooling, and roasting for 5-8 h at the temperature of 400-430 ℃; and after natural cooling, respectively washing with ultrapure water and ethanol to remove impurities attached to the surface, and drying at 60-65 ℃.

6. The method for preparing a visible light catalyst according to claim 1, wherein: and thirdly, carrying out ultrasonic treatment for 4-6 h.

7. The method for preparing a visible light catalyst according to claim 1, wherein: and step four, transferring the precipitate into a hydrothermal reaction kettle, keeping the hydrothermal reaction kettle at the temperature of 140-150 ℃ for 3-5 hours, naturally cooling, washing the precipitate with ultrapure water and ethanol respectively, and drying the precipitate at the temperature of 60-80 ℃ for 10-15 hours to obtain the target product.

Technical Field

The invention relates to the technical field of preparation of photocatalysts, in particular to a preparation method of a visible light photocatalyst.

Background

Ag₃PO₄Due to the high oxidation activity of electron-hole pairs, strong photooxidation ability and high efficiency of photocatalytic degradation of organic pollutants, widely applied in the fields of materials, environment and energy. However, Ag₃PO₄Is unstable under visible light, can be photo-reduced or decomposed into a weakly active simple substance of silver, and consumes a large amount of the simple substanceSilver increases the cost of the photocatalyst, limiting its practical industrial application.

Disclosure of Invention

The present invention aims to provide a preparation method of a visible light photocatalyst to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of a visible light catalyst comprises the following steps:

step one, sequentially adding a certain amount of polyethylene glycol and a certain amount of sodium hydroxide solution into bismuth nitrate, adding ammonia water into the bismuth nitrate, and uniformly stirring;

step two, heating the precipitate generated in the step one for a period of time, cooling, taking out the powder, roasting and drying to obtain alpha-Bi₂O₃；

Step three, mixing alpha-Bi₂O₃Uniformly dispersing in deionized water, and ultrasonic treating to obtain alpha-Bi₂O₃Uniformly dispersing in water;

step four, dropwise adding silver nitrate, stirring to dissolve the silver nitrate, and then dropwise adding a disodium hydrogen phosphate solution to obtain a precipitate; heating the precipitate, naturally cooling, cleaning, and drying to obtain the target product Ag₃PO₄/α-Bi₂O₃。

Preferably, ammonia water is used for adjusting the pH value of the solution in the first step to be within a range of 9-10.

Preferably, the sodium hydroxide solution in the first step is a sodium hydroxide solution without carbon dioxide.

Preferably, the Ag is₃PO₄And alpha-Bi₂O₃The molar ratio of (A) to (B) is 0.1:1 to 1: 1.

Preferably, the precipitate generated in the second step is transferred to a hydrothermal reaction kettle and is continuously heated for 2-3 hours at the temperature of 90-110 ℃; taking out the powder after cooling, and roasting for 5-8 h at the temperature of 400-430 ℃; and after natural cooling, respectively washing with ultrapure water and ethanol to remove impurities attached to the surface, and drying at 60-65 ℃.

Preferably, the third step is ultrasonic treatment for 4-6 h.

Preferably, the fourth step is to transfer the precipitate into a hydrothermal reaction kettle, keep the precipitate for 3-5 hours at 140-150 ℃, respectively wash the precipitate with ultrapure water and ethanol after natural cooling, and then dry the precipitate for 10-15 hours at 60-80 ℃ to finally obtain the target product.

Compared with the prior art, the invention has the beneficial effects that: the photocatalyst Ag is obtained by adopting the preparation method of the invention₃PO₄/α-Bi₂O₃Has the advantages of high efficiency, stability, simplicity and easy obtaining, and can improve the photocatalytic degradation efficiency of organic pollutants.

Drawings

FIG. 1 is a scanning electron micrograph of AB-x/1;

FIG. 2 is a transmission electron micrograph of AB-0.6/1;

FIG. 3 is an X-ray photoelectron spectrum of AB-0.6/1.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in 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.

Referring to fig. 1-3, the present invention provides the following technical solutions: a preparation method of a visible light catalyst comprises the following steps:

step one, sequentially adding a certain amount of polyethylene glycol and a certain amount of sodium hydroxide solution into bismuth nitrate, adding ammonia water into the bismuth nitrate, and uniformly stirring;

step two, heating the precipitate generated in the step one for a period of time, cooling, taking out the powder, roasting and drying to obtain alpha-Bi₂O₃；

Step three, mixing alpha-Bi₂O₃Uniformly dispersing in deionized water, and ultrasonic treating to obtain alpha-Bi₂O₃In waterDispersing uniformly;

step four, dropwise adding silver nitrate, stirring to dissolve the silver nitrate, and then dropwise adding a disodium hydrogen phosphate solution to obtain a precipitate; heating the precipitate, naturally cooling, cleaning, and drying to obtain the target product Ag₃PO₄/α-Bi₂O₃。

Example 1

0.5mol of bismuth nitrate is firstly added into a 100ml beaker, then 2ml of polyethylene glycol and 0.4mol of sodium hydroxide solution are added, 5ml of ammonia water is added into the mixture, and the solution is stirred uniformly by a magnetic stirrer. Then transferring the generated precipitate into a hydrothermal reaction kettle of polytetrafluoroethylene, and continuously heating for 2h at 90 ℃. After cooling, the powder is taken out and roasted for 5h at the temperature of 400 ℃. After natural cooling, respectively washing with ultrapure water and ethanol for multiple times to remove impurities attached to the surface, and drying at 60 ℃ to obtain alpha-Bi₂O₃. Thirdly, 50mg of alpha-Bi₂O₃Uniformly dispersing in 40ml of deionized water, and then carrying out ultrasonic treatment for 4h to ensure that Bi is dispersed₂O₃The dispersion is uniform in water. Subsequently, 5mmol of silver nitrate was added dropwise and dissolved with stirring, and then a 0.2mol/L disodium hydrogenphosphate solution was added dropwise thereto to obtain a brown yellow precipitate. Transferring the precipitate into a hydrothermal reaction kettle of polytetrafluoroethylene, keeping the temperature at 140 ℃ for 3h, naturally cooling, washing with ultrapure water and ethanol for multiple times respectively, and drying at 60 ℃ for 10h to obtain a target product AB-1/1.

Example 2

0.5mol of bismuth nitrate is firstly added into a 100ml beaker, then 2ml of polyethylene glycol and 0.4mol of sodium hydroxide solution are added, 4ml of ammonia water is added into the mixture, and the solution is stirred uniformly by a magnetic stirrer. Then transferring the generated precipitate into a hydrothermal reaction kettle of polytetrafluoroethylene, and continuously heating for 3h at 100 ℃. After cooling, the powder is taken out and roasted for 5h at the temperature of 420 ℃. After natural cooling, respectively washing with ultrapure water and ethanol for multiple times to remove impurities attached to the surface, and drying at 70 ℃ to obtain alpha-Bi₂O₃. Thirdly, 50mg of alpha-Bi₂O₃Uniformly dispersing in 40ml of deionized water, and then carrying out ultrasonic treatment for 5 hours to ensure that Bi is dispersed₂O₃The dispersion is uniform in water. 4mmol of silver nitrate was added dropwise, and then dissolved with constant stirring, followed by dropwise addition of a 0.1mol/L disodium hydrogenphosphate solution thereto to give a brown-yellow precipitate. Transferring the precipitate into a hydrothermal reaction kettle of polytetrafluoroethylene, keeping the temperature at 150 ℃ for 4h, naturally cooling, washing with ultrapure water and ethanol for multiple times, and drying at 70 ℃ for 10h to obtain a target product AB-0.8/1.

Example 3

0.5mol of bismuth nitrate is firstly added into a 100ml beaker, then 2ml of polyethylene glycol and 0.5mol of sodium hydroxide solution are added, 6ml of ammonia water is added into the mixture, and the solution is stirred uniformly by a magnetic stirrer. Then transferring the generated precipitate into a hydrothermal reaction kettle of polytetrafluoroethylene, and continuously heating for 3h at 100 ℃. After cooling, the powder is taken out and roasted for 5h at the temperature of 420 ℃. After natural cooling, respectively washing with ultrapure water and ethanol for multiple times to remove impurities attached to the surface, and drying at 70 ℃ to obtain alpha-Bi₂O₃. Thirdly, 50mg of alpha-Bi₂O₃Uniformly dispersing in 40ml of deionized water, and then carrying out ultrasonic treatment for 5 hours to ensure that Bi is dispersed₂O₃The dispersion is uniform in water. 3mmol of silver nitrate was added dropwise, and then dissolved with constant stirring, followed by dropwise addition of a 0.1mol/L disodium hydrogenphosphate solution thereto to give a brown-yellow precipitate. Transferring the precipitate into a hydrothermal reaction kettle of polytetrafluoroethylene, keeping the temperature at 150 ℃ for 4h, naturally cooling, washing with ultrapure water and ethanol for multiple times, and drying at 70 ℃ for 12h to obtain a target product AB-0.6/1.

Example 4

Under the condition of visible light, the reaction temperature is controlled to be 40 ℃, and 5mg of Ag is taken as the thermosensitive catalyst in example 1₃PO₄/α-Bi₂O₃Adding the mixture into 5mL of methyl orange solution with the concentration of 40mg/L, maintaining the rotating speed at 15 r/min, and degrading for 5min, wherein the degradation rate of the methyl orange reaches 99.2%.

Example 5

In visible light conditionsNext, the reaction temperature was controlled to 30 ℃ to obtain 6mg of Ag as the heat-sensitive catalyst in example 2₃PO₄/α-Bi₂O₃Adding the mixture into 10mL of methyl orange solution with the concentration of 30mg/L, maintaining the rotating speed at 15 r/min, and degrading for 6min, wherein the degradation rate of the methyl orange reaches 99.4%.

Example 6

Under the condition of visible light, the reaction temperature is controlled to be 30 ℃, and 10mg of Ag is taken as the thermosensitive catalyst in example 3₃PO₄/α-Bi₂O₃Adding 20mL of methylene blue solution with the concentration of 40mg/L, maintaining the rotating speed at 15 r/min, and degrading for 5min, wherein the degradation rate of the methylene blue reaches 99.5%.

Example 7

Under the condition of visible light, the reaction temperature is controlled to be 35 ℃, and 10mg of Ag is taken as the thermosensitive catalyst in example 1₃PO₄/α-Bi₂O₃Adding 20mL of methylene blue solution with the concentration of 40mg/L, maintaining the rotating speed at 15 r/min, and degrading for 5min, wherein the degradation rate of the methylene blue reaches 99.9%.

Adjusting Ag by changing the amount of silver nitrate₃PO₄And alpha-Bi₂O₃And obtaining a series of products with different proportions. The products of different molar ratios are represented by AB-x/1, x/1(0.1/1, 0.2/1, 0.4/1, 0.6/1, 0.8/1, 1/1) representing Ag₃PO₄homo-alpha-Bi₂O₃The ratio of (a) to (b).

Under the condition of visible light, Ag is used at the temperature of 30-35 ℃, the catalyst concentration of 30mg/L, the rotation number of 40-50 rpm and the catalyst concentration of 3-5 mg/L₃PO₄/α-Bi₂O₃The methylene blue and the methyl orange are degraded, and the degradation rate reaches 99.9 percent.

In conclusion, the photocatalyst Ag is obtained by the preparation method₃PO₄/α-Bi₂O₃Has the advantages of high efficiency, stability, simplicity and easy obtaining, and can improve the photocatalytic degradation efficiency of organic pollutants.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.