阅读说明：本技术 一种卤氧化铋/g-C3N4异质结光催化剂的制备 (Bismuth oxyhalide/g-C3N4Preparation of heterojunction photocatalyst ) 是由 陈玥希 王晓飞 张晶晶 常珈菘 张伟杰 曹江行 郭驾宇 范美强 于 2019-12-30 设计创作，主要内容包括：本发明涉及到一种卤氧化铋/g-C<Sub>3</Sub>N<Sub>4</Sub>异质结光催化剂的制备。其特征在于：通过水热反应使得卤氧化铋生长在g-C<Sub>3</Sub>N<Sub>4</Sub>纳米管上形成异质结,获得了比单一纳米管状的g-C<Sub>3</Sub>N<Sub>4</Sub>具有更好的光催化性能,较高的孔隙率和较大的比表面积；卤氧化铋/g-C<Sub>3</Sub>N<Sub>4</Sub>纳米管异质结,使电子-空穴对有效的分离,电荷载体可以跨越异质结构的界面转移以抑制重组,进而大大促进了g-C3N4的光催化性能,在卤氧化铋/g-C<Sub>3</Sub>N<Sub>4</Sub>纳米管异质结中,卤氧化铋所占百分比为2％,5％,10％,20％,当其浓度为20％时实现了优异的降解效率。本发明制备工艺简单、成本低廉、重复性强,表现出优于单独的氮化碳纳米管的光催化性能,大大地提高了抗生素降解率,使其在光催化领域具有广阔的应用前景。(The invention relates to bismuth oxyhalide/g-C 3 N 4 And (3) preparing a heterojunction photocatalyst. The method is characterized in that: growth of bismuth oxyhalide at g-C by hydrothermal reaction 3 N 4 The heterojunction is formed on the nanotube, and g-C of a shape of a single nanotube is obtained 3 N 4 The photocatalyst has better photocatalytic performance, higher porosity and larger specific surface area; bismuth oxyhalide/g-C 3 N 4 The nanotube heterojunction enables the effective separation of electron-hole pairs, and the charge carriers can transfer across the interface of the heterostructure to inhibit recombination, thereby greatly promoting the photocatalytic performance of g-C3N4, in terms of bismuth oxyhalide/g-C 3 N 4 In the nanotube heterojunction, the bismuth oxyhalide accounts for 2%, 5%, 10% and 20% of the heterojunction, and the concentration of the bismuth oxyhalide is equal toExcellent degradation efficiency was achieved at 20%. The preparation method has the advantages of simple preparation process, low cost and strong repeatability, shows the photocatalytic performance superior to that of a single carbon nitride nanotube, greatly improves the degradation rate of antibiotics, and has wide application prospect in the field of photocatalysis.)

1. Bismuth oxyhalide/g-C₃N₄The preparation of the heterojunction photocatalyst is characterized in that: (1) dispersing bismuth oxyhalide including one or more of bismuth oxyiodide, bismuth oxybromide, bismuth oxychloride and bismuth oxyfluoride in g-C by shaking₃N₄Carbon nanotube, g-C₃N₄Carbon nanosheet, g-C₃N₄Forming a heterojunction in one or more solutions of the carbon nanotubes; (2) mixing bismuth oxyhalide (including one or more of bismuth oxyiodide, bismuth oxybromide, bismuth oxychloride and bismuth oxyfluoride) with g-C₃N₄Carbon nanotube, g-C₃N₄Carbon nanosheet, g-C₃N₄Mixing one or more solutions in the carbon nano tube, placing the mixture in a polytetrafluoroethylene inner container, and heating the mixture in water to form a heterojunction; (3) the percentage of the total components of the bismuth oxyhalide is 2 to 50 percent; (4) the product is suitable for the field of photocatalytic degradation.

2. A bismuth oxyhalide/g-C as claimed in claim 1₃N₄The preparation of the heterojunction photocatalyst is characterized in that: the bismuth oxyhalide is one or more of bismuth oxyiodide, bismuth oxybromide, bismuth oxychloride and bismuth oxyfluoride, and is prepared by mixing bismuth nitrate and halide salt.

3. The process of claim 2 wherein the bismuth oxyhalide is present in an amount of bismuth per gram-C₃N₄The preparation of the heterojunction photocatalyst is characterized in that: the halogen bismuth oxide is prepared by mixing bismuth nitrate and halide salt₃N₄Bismuth oxyhalide/g-C in solution₃N₄And (4) preparing a heterojunction.

4. The process of claim 1 wherein said bismuth oxyhalide is bismuth oxyhalide/g-C₃N₄Preparation of a heterojunction photocatalyst, characterized in thatIn g-C₃N₄Is in the shape of block, sheet or nanotube, and is prepared from one or more of thiourea, urea and melamine.

5. A bismuth oxyhalide/g-C according to claim 1₃N₄The preparation degradation material of the heterojunction photocatalyst is antibiotic organic refractory substances such as tetracycline, tetracycline hydrochloride and the like, and belongs to the field of photocatalytic degradation.

6. The method is characterized by comprising the following steps:

1) heating a certain mass of melamine to 550-600 ℃ at a heating rate of 10 ℃/min, preserving heat for 2-3 h, cooling to room temperature, and grinding uniformly;

2) placing the product obtained in the step 1) in a concentrated sulfuric acid solution with a certain volume, and stirring for 0.5-0.6 h, wherein the temperature is controlled at 40-60 ℃;

3) rapidly adding a certain volume of deionized water into the solution obtained in the step 2), and stirring until a transparent solution is formed, wherein the temperature is controlled to be 80-100 ℃;

4) slowly adding the solution obtained in the step 3) into methanol with a certain volume, stirring for 3-4 hours to form a white precipitate, cooling to room temperature, collecting the precipitate through centrifugation, washing with water and alcohol, and drying for 24 hours, wherein the temperature is controlled at 60-80 ℃;

5) heating the product obtained in the step 4) to 550-600 ℃ at a heating rate of 5 ℃/min, and preserving heat for 2-3 h to obtain a yellow powder mark g-C₃N₄。

6) Taking a certain mass of g-C₃N₄Adding into a certain amount of KI glycol solution, and stirring vigorously to obtain Bi (NO) with a certain mass ratio of g-C3N4₃)₃·5H₂Adding O into a certain volume of ethylene glycol, stirring for 2-3 h, and dropwise adding to g-C₃N₄Mixing KI in a glycol solution to obtain a mixed solution;

7) transferring the product obtained in the step 6) into a polytetrafluoroethylene lining autoclave, and heating for 3-4 h, wherein the temperature is controlled at 130-260 ℃;

8) washing the product of the step 7) with ethanol and distilled water for a plurality of times, and placing the product in a vacuum drying ovenDrying for 10-12 h, controlling the temperature at 30-50 ℃ to obtain the final product BiOI (110)/g-C₃N₄A nanotube heterojunction.

Technical Field

The invention belongs to the technical field of preparation of novel clean catalytic materials for semiconductor photocatalysis, and particularly relates to bismuth oxyhalide/g-C₃N₄And (3) preparing a heterojunction photocatalyst.

Background

With the rapid development of economy, environmental pollution is becoming more severe, and water pollution is more severe among numerous pollutants. Common water pollutants comprise organic substances, inorganic salts, toxic chemicals, industrial wastewater and the like, and the traditional method for treating water pollution is difficult to remove some toxic organic pollutants or has a low removal effect and is easy to cause secondary pollution. In recent years, semiconductor heterojunction photocatalytic materials have attracted extensive attention in the field of photodegradation of organic pollutants in wastewater.

Metal-free graphitic carbonitrides (g-C)₃N₄) The high degree of agglomeration and the heptaplatin ring structure lead the compound to have good physical and chemical stability and can respond to a visible light region, and the preparation method is simple and easy to synthesize. These excellent properties are such that g-C₃N₄Becoming a promising candidate for visible light photocatalytic applications utilizing solar energy. However, pure g-C₃N₄There are drawbacks such as: fast recombination of photo-generated electrons, small specific surface area, low utilization efficiency of visible light and the like. These defects greatly affect the application of g-C3N 4. Thus, the synthesis is based on g-C₃N₄The modified photocatalyst with high photocatalytic activity has important significance.

Patent 1(CN 102218339B discloses a graphite phase carbon nitride powder, its preparation method and application, the field of photocatalytic degradation), which is characterized in that: the powder adopts an aromatic multi-element heterocyclic ring consisting of carbon elements and nitrogen elements as a plane repeating unit and has a layered graphene structure. But the catalytic degradation structure is single, the degradation material property is low, and the catalyst can be further compounded with other materials.

Patent 2(CN 110182773 a, disclosing a preparation of 0-dimensional vanadate quantum dot/two-dimensional graphite nitrogen carbide nanosheet), which is characterized in that: the invention utilizes the photoelectric activity, the up-conversion absorption and the nitrogen coordination sites of the ultrathin graphite carbonitride and the highly dispersed vanadate nanocrystals, and the strong coupling and the band gap matching between the ultrathin graphite carbonitride and the highly dispersed vanadate nanocrystals to prepare the composite material through an in-situ reaction approach, thereby providing the multifunctional 0-dimensional/two-dimensional nanomaterial for various photoelectron applications.

Disclosure of Invention

The invention aims to provide bismuth oxyhalide/g-C₃N₄The preparation of the heterojunction photocatalyst is applicable to the field of catalytic degradation, and provides a new idea for catalytic degradation of organic matters such as antibiotics and the like.

The method is characterized in that:

1) dispersing bismuth oxyhalide including one or more of bismuth oxyiodide, bismuth oxybromide, bismuth oxychloride and bismuth oxyfluoride in g-C by shaking₃N₄Carbon nanotube, g-C₃N₄Carbon nanosheet, g-C₃N₄Forming a heterojunction in one or more solutions of the carbon nanotubes;

2) the bismuth oxyhalide accounts for 2 to 50 percent of the total mass percent;

3) mixing bismuth oxyhalide (including one or more of bismuth oxyiodide, bismuth oxybromide, bismuth oxychloride and bismuth oxyfluoride) with g-C₃N₄Carbon nanotube, g-C₃N₄Carbon nanosheet, g-C₃N₄Mixing one or more solutions in the carbon nano tube, placing the mixture in a polytetrafluoroethylene inner container, and heating the mixture in water to form a heterojunction;

4) the bismuth oxyhalide is one or more of bismuth oxyiodide, bismuth oxybromide, bismuth oxychloride and bismuth oxyfluoride, and is prepared by mixing bismuth nitrate and halide salt;

5) the halogen bismuth oxide is prepared by mixing bismuth nitrate and halide salt₃N₄Bismuth oxyhalide/g-C in solution₃N₄Preparing a heterojunction;

6) bismuth oxyhalide/g-C₃N₄Preparation of a heterojunction photocatalyst, characterized in that g-C₃N₄Is in the shape of block, sheet and nano tube, and is prepared from one or more of thiourea, urea and melamine;

7) bismuth oxyhalide/g-C₃N₄The preparation degradation material of the heterojunction photocatalyst is antibiotic organic refractory substances such as tetracycline, tetracycline hydrochloride and the like, and belongs to the field of photocatalytic degradation;

the specific method of the invention is as follows:

synthesizing the carbon nitride nanotube:

1) heating a certain mass of melamine to 550-600 ℃ at a heating rate of 10 ℃/min, preserving heat for 2-3 h, cooling to room temperature, and grinding uniformly;

2) placing the product obtained in the step 1) in a concentrated sulfuric acid solution with a certain volume, and stirring for 0.5-0.6 h, wherein the temperature is controlled at 40-60 ℃;

3) rapidly adding a certain volume of deionized water into the solution obtained in the step 2), and stirring until a transparent solution is formed, wherein the temperature is controlled to be 80-100 ℃;

4) slowly adding the solution obtained in the step 3) into methanol with a certain volume, stirring for 3-4 hours to form a white precipitate, cooling to room temperature, collecting the precipitate through centrifugation, washing with water and alcohol, and drying for 24 hours, wherein the temperature is controlled at 60-80 ℃;

5) heating the product obtained in the step 4) to 550-600 ℃ at a heating rate of 5 ℃/min, and preserving heat for 2-3 h to obtain a yellow powder mark g-C₃N₄。

Bismuth oxyhalide/g-C₃N₄Preparing the nanotube:

1) taking a certain mass of g-C₃N₄Adding a certain amount of potassium halideAdding Bi (NO) in a certain mass ratio of g-C3N4 into an ethylene glycol solution under the condition of vigorous stirring₃)₃·5H₂Adding O into a certain volume of ethylene glycol, stirring for 2-3 h, and dropwise adding to g-C₃N₄Mixing potassium halide in glycol solution to obtain mixed solution;

2) transferring the product obtained in the step 1) into a polytetrafluoroethylene lining autoclave, and heating for 3-4 h, wherein the temperature is controlled at 130-260 ℃;

3) washing the product obtained in the step 2) with ethanol and distilled water for several times, and drying the product in a vacuum drying oven for 10 to 12 hours at the temperature of 30 to 5 ℃ to obtain the final product bismuth oxyhalide/g-C₃N₄A nanotube heterojunction.

Compared with other products, the invention has the following advantages:

1) nanotube shaped g-C₃N₄The photocatalyst has better photocatalytic performance, higher porosity and larger specific surface area;

2) nanotube shaped g-C₃N₄The nanotube heterojunction photocatalytic material shows higher polymerization degree and fewer defects;

3) bismuth oxyhalide/g-C₃N₄The nanotube heterojunction enables electron-hole pairs to be effectively separated, and charge carriers can transfer across the interface of the heterostructure to inhibit recombination, so that the photocatalytic performance of g-C3N4 is greatly promoted.

4) The preparation method has the advantages of simple preparation process, low cost, strong repeatability and great market commercialization potential.

Drawings

FIG. 1 is an XRD pattern of BiOI, 10% -BiOI/CNNT, CNNT;

FIG. 2 is a graph showing the photocatalytic activity of five concentrations of BiOI (110)/g-C3N4 in degrading tetracycline hydrochloride under light;

FIG. 3 is a graph showing the UV-VIS diffuse reflectance absorption spectra of BiOI (110)/g-C3N4 at five concentrations;

Detailed Description

The specific method of the invention is as follows:

example 1:

BiOI、g-C₃N₄、10％BiOI(110)/g-C₃N₄preparation of heterojunction photocatalyst:

1. synthesizing the carbon nitride nanotube:

1) heating a certain mass of melamine to 550-600 ℃ at a heating rate of 10 ℃/min, preserving heat for 2-3 h, cooling to room temperature, and grinding uniformly;

2) placing the product obtained in the step 1) in a concentrated sulfuric acid solution with a certain volume, and stirring for 0.5-0.6 h, wherein the temperature is controlled at 40-60 ℃;

3) rapidly adding a certain volume of deionized water into the solution obtained in the step 2), and stirring until a transparent solution is formed, wherein the temperature is controlled to be 80-100 ℃;

4) slowly adding the solution obtained in the step 3) into methanol with a certain volume, stirring for 3-4 hours to form a white precipitate, cooling to room temperature, collecting the precipitate through centrifugation, washing with water and alcohol, and drying for 24 hours, wherein the temperature is controlled at 60-80 ℃;

5) heating the product obtained in the step 4) to 550-600 ℃ at a heating rate of 5 ℃/min, and preserving heat for 2-3 h to obtain a yellow powder mark g-C₃N₄。

2.BiOI(110)/g-C₃N₄Preparing the nanotube:

1) taking a certain mass of g-C₃N₄Adding into a certain amount of KI glycol solution, stirring vigorously to obtain 0%, 10%, and 100% Bi (NO) g-C3N4₃)₃·5H₂Adding O into 10ml of ethylene glycol, stirring for 2-3 h, and dropwise adding to g-C₃N₄Mixing KI in a glycol solution to obtain a mixed solution;

2) transferring the product obtained in the step 1) into a polytetrafluoroethylene lining autoclave, and heating for 3-4 h, wherein the temperature is controlled at 130-260 ℃;

3) washing the product obtained in the step 2) with ethanol and distilled water for several times, and drying in a vacuum drying oven for 10-12 h at the temperature of 3-50 ℃ to obtain the final product BiOI (110)/g-C₃N₄A nanotube heterojunction.

XRD scan analysis of example 1 showed that the Bioi (110)/CNNT heterostructures with different exposed faces exhibited the same diffraction angles as the CNNT and Bioi components, as shown in fig. 1. Notably, we can see from the XRD pattern that the intensity of the CNNT peak is increased in the 110-BiOI/CNNT heterostructure.

Example 2:

preparation and catalytic degradation of 2%, 5%, 10%, 20% BiOI (110)/g-C3N4 heterojunction photocatalyst:

1. synthesizing the carbon nitride nanotube:

1) heating a certain mass of melamine to 550-600 ℃ at a heating rate of 10 ℃/min, preserving heat for 2-3 h, cooling to room temperature, and grinding uniformly;

2) placing the product obtained in the step 1) in a concentrated sulfuric acid solution with a certain volume, and stirring for 0.5-0.6 h, wherein the temperature is controlled at 40-60 ℃;

3) rapidly adding a certain volume of deionized water into the solution obtained in the step 2), and stirring until a transparent solution is formed, wherein the temperature is controlled to be 80-100 ℃;

4) slowly adding the solution obtained in the step 3) into methanol with a certain volume, stirring for 3-4 hours to form a white precipitate, cooling to room temperature, collecting the precipitate through centrifugation, washing with water and alcohol, and drying for 24 hours, wherein the temperature is controlled at 60-80 ℃;

5) heating the product obtained in the step 4) to 550-600 ℃ at a heating rate of 5 ℃/min, and preserving heat for 2-3 h to obtain a yellow powder mark g-C₃N₄。

2.BiOI(110)/g-C₃N₄Preparing the nanotube:

1) taking a certain mass of g-C₃N₄Adding into a certain amount of KI glycol solution, stirring vigorously to obtain a mixture containing 2%, 5%, 10%, and 20% of Bi (NO) in g-C3N4₃)₃·5H₂Adding O into 10ml of ethylene glycol, stirring for 2-3 h, and dropwise adding to g-C₃N₄Mixing KI in a glycol solution to obtain a mixed solution;

2) transferring the product obtained in the step 1) into a polytetrafluoroethylene lining autoclave, and heating for 3-4 h, wherein the temperature is controlled at 130-260 ℃;

3) washing the product obtained in the step 2) with ethanol and distilled water for several times, and drying in a vacuum drying oven for 10-12 h at the temperature of3-50 ℃ to obtain a final product BiOI (110)/g-C₃N₄A nanotube heterojunction.

The product obtained in examples 1 and 2 was subjected to photocatalytic performance test on tetracycline hydrochloride with concentration of 30mg/l, which is one of environmentally-polluted tetracyclines, and a blank control group was added, as shown in fig. 2, and under the irradiation of visible light, the direct photocatalytic degradation of tetracycline hydrochloride in the blank control group was negligible. The degradation rates of the four samples are normalized as follows: 20% BiOI/CNNT > 10% BiOI/CNNT > 2% BiOI/CNNT > 0% BiOI/CNNT. It can be seen that the degradation rate can be improved by the compound semiconductor.

Example 3:

preparation and ultraviolet-visible diffuse reflection analysis of a pure sample BiOI:

1. preparation of a separate sample BiOI (110):

1) taking KI glycol solution with certain mass, and stirring the KI glycol solution with certain mass to obtain Bi (NO) with certain mass₃)₃·5H₂Adding O into 10ml of ethylene glycol, stirring for 2-3 h, and dropwise adding to g-C₃N₄Mixing KI in a glycol solution to obtain a mixed solution;

2) transferring the product obtained in the step 1) into a polytetrafluoroethylene lining autoclave, and heating for 3-4 h, wherein the temperature is controlled at 130-260 ℃;

3) washing the product obtained in the step 2) with ethanol and distilled water for several times, and drying the product in a vacuum drying oven for 10-12 hours at the temperature of 3-50 ℃ to obtain the final product BiOI (110) nanotube heterojunction.

The products obtained in examples 1, 2 and 3 were subjected to ultraviolet-visible diffuse reflectance spectrum analysis, and as shown in FIG. 3, the data graphs of forbidden band widths obtained by processing ultraviolet-visible diffuse reflectance absorption data with the use of the Tauc formula for CNNT, 2% BiOI (110)/CNNT, 5% BiOI (110)/CNNT, 10% BiOI (110)/CNNT, 20% BiOI (110)/CNNT and BiOI. The calculated forbidden band widths are respectively as follows: the 20 percent BiOI (110)/CNNT degradation rate is the highest with the values of 2.610eV, 2.749eV, 2.649eV, 2.677eV, 2.638eV and 3.1556 eV.

The foregoing detailed description is exemplary only, and is not intended to limit the scope of the patent, as defined by the appended claims; any equivalent alterations or modifications made according to this patent are intended to fall within the scope of this patent.