Bismuth-bismuth oxycarbonate composite photocatalyst and preparation method and application thereof

文档序号：1789648 发布日期：2021-11-05 浏览：37次中文

阅读说明：本技术 一种铋-碳酸氧铋复合光催化剂及其制备方法和应用 (Bismuth-bismuth oxycarbonate composite photocatalyst and preparation method and application thereof ) 是由谈国强毕钰杨迁张碧鑫王勇王敏冯帅军刘宸君任慧君夏傲于 2021-09-09 设计创作，主要内容包括：本发明提供一种铋-碳酸氧铋复合光催化剂及其制备方法和应用,该制备方法包括以下步骤：步骤1：按(0.25-7.5)：(1-3)的摩尔比,将纳米花球状Bi-(2)O-(2)CO-(3)粉体和NaBH-(4)分散在去离子水中,得到前驱液A；按(0.5-7.5)：(1-3)的摩尔比,将片状Bi-(2)O-(2)CO-(3)粉体和NaBH-(4)分散在去离子水中,得到前驱液B；步骤2：将前驱液A或前驱液B混合均匀,之后过滤得到的混合液,将得到的滤饼依次洗涤、干燥得到纳米花球状或片状铋-碳酸氧铋复合光催化剂,可实现在可见光和近红外光下对四环素的高效降解,在抗生素降解中具有良好的应用前景。(The invention provides a bismuth-bismuth oxycarbonate composite photocatalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps: step 1: according to the formula (0.25-7.5): (1-3) molar ratio of Bi in the form of nano flower spheres 2 O 2 CO 3 Powder and NaBH 4 Dispersing in deionized water to obtain a precursor solution A; according to the formula (0.5-7.5): (1-3) In a molar ratio of Bi in a flake form 2 O 2 CO 3 Powder and NaBH 4 Dispersing in deionized water to obtain a precursor liquid B; step 2: the precursor solution A or the precursor solution B is uniformly mixed, then the obtained mixed solution is filtered, and the obtained filter cake is sequentially washed and dried to obtain the nano flower-shaped or sheet-shaped bismuth-bismuth oxycarbonate composite photocatalyst, so that the tetracycline can be efficiently degraded under visible light and near infrared light, and the nano flower-shaped or sheet-shaped bismuth-oxycarbonate composite photocatalyst has a good application prospect in the degradation of antibiotics.)

1. The preparation method of the bismuth-bismuth oxycarbonate composite photocatalyst is characterized by comprising the following steps of:

step 1: according to the formula (0.25-7.5): (1-3) molar ratio of Bi in the form of nano flower spheres₂O₂CO₃Powder and NaBH₄Dispersing in deionized water to obtain a precursor solution A;

according to the formula (0.5-7.5): (1-3) molar ratio of Bi in flake form₂O₂CO₃Powder and NaBH₄Dispersing in deionized water to obtain a precursor liquid B;

step 2: and uniformly mixing the precursor solution A or the precursor solution B, filtering the obtained mixed solution, and sequentially washing and drying the obtained filter cake to obtain the bismuth-bismuth oxycarbonate composite photocatalyst.

2. The method for preparing a bismuth-bismuth oxycarbonate composite photocatalyst according to claim 1, wherein the nano flower-like spherical Bi in step 1₂O₂CO₃The powder is obtained by the following steps:

mixing sodium citrate and Bi (NO) at a molar ratio of 1:2₃)₃·5H₂Dissolving O in HNO₃In the solution, NaOH solution is used for adjusting the pH value of the obtained mixed system to 5-5.5, and then the mixed system is uniformly stirred to obtain a precursor solution a, wherein Bi in the precursor solution a³⁺The concentration of the precursor is 0.05-0.2mol/L, the precursor solution a is subjected to hydrothermal reaction for 18-24h at the temperature of 180-200 ℃, and finally, precipitates in the reaction solution are sequentially washed, dried and ground to obtain the nano flower-ball-shaped Bi₂O₂CO₃And (3) powder.

3. The method for preparing the bismuth-bismuth oxycarbonate composite photocatalyst according to claim 1, wherein the flake Bi in the step 1 is Bi₂O₂CO₃The powder is obtained by the following steps:

adding Bi (NO)₃)₃·5H₂HNO of O₃Solution and Na₂CO₃Mixing the aqueous solution of (B) to obtain Bi (NO)₃)₃·5H₂O and Na₂CO₃In a molar ratio of (0.5-1.5): (0.45-13.5), filtering the obtained mixed solution, and sequentially washing and drying the obtained filter cake to obtain the flaky Bi₂O₂CO₃And (3) powder.

4. The method for preparing the bismuth-bismuth oxycarbonate composite photocatalyst according to claim 1, wherein the step 1 is performed firstly for every 0.001mol of Bi₂O₂CO₃Powder and NaBH 0.00025-0.0025 mol/per 0.00025₄Respectively adding the mixture into 10-30mL of deionized water, uniformly mixing to obtain a dispersion liquid a and a solution a correspondingly, and uniformly mixing the dispersion liquid a and the solution a according to the volume ratio of 1:1 to obtain a precursor liquid A;

step 1, every 0.001mol of Bi₂O₂CO₃Powder and NaBH in an amount of 0.0005-0.0025 mol/l₄Respectively adding the mixture into 10-30mL of deionized water, uniformly mixing to obtain a dispersion liquid B and a solution B, and uniformly mixing the dispersion liquid B and the solution B according to the volume ratio of 1:1 to obtain a precursor liquid B.

5. The method for preparing the bismuth-bismuth oxycarbonate composite photocatalyst according to claim 4, wherein the Bi is contained in the precursor liquid A and the precursor liquid B₂O₂CO₃Powder and NaBH₄Adding into deionized water, stirring for 20-50min to obtain dispersion and solution.

6. The method for preparing the bismuth-bismuth oxycarbonate composite photocatalyst according to claim 1, wherein in the step 2, the precursor solution A or the precursor solution B is stirred for 20-40min, and the obtained mixed solution is filtered.

7. The method for preparing the bismuth-bismuth oxycarbonate composite photocatalyst according to claim 1, wherein the washed filter cake is dried at 10-60 ℃ for 8-15 hours in step 2, so as to obtain the nano flower-shaped spherical bismuth-bismuth oxycarbonate composite photocatalyst.

8. A bismuth-bismuth oxycarbonate composite photocatalyst obtained by the method for preparing the bismuth-bismuth oxycarbonate composite photocatalyst according to any one of claims 1 to 7.

9. The bismuth-bismuth oxycarbonate composite photocatalyst according to claim 8, wherein the simple substance of Bi in the bismuth-bismuth oxycarbonate composite photocatalyst is in a hexagonal system, and the space point group is R-3m (166).

10. The use of the bismuth-bismuth oxycarbonate composite photocatalyst of claim 8 or 9 in visible light and near infrared light degradation of antibiotics.

Technical Field

The invention belongs to the technical field of preparation of photocatalytic materials, and particularly relates to a bismuth-bismuth oxycarbonate composite photocatalyst as well as a preparation method and application thereof.

Background

The rapid development of the industry causes the air pollution to be more serious, and the sustainable development of the human society and the physical health of people are seriously influenced. The photocatalysis technology can be used for treating air pollution, has good effect, takes sunlight as a driving force, has low cost and has obvious advantages.

Bi₂O₂CO₃The photocatalyst has been widely noticed and researched as a semiconductor photocatalyst having unique crystal and electronic structure and excellent activity. However, Bi alone₂O₂CO₃Due to the defects of large forbidden band width (about 3.2eV), narrow photoresponse range and the like, the photocatalytic activity of the material is reduced, and the practical application is limited. A number of technologists control the formation of photogenerated electron-hole complexes by depositing noble metals to form heterojunctions on the surface of semiconductor catalysts. Semiconductor catalyst surface depositionThe noble metal is helpful for improving the separation efficiency of photoproduction electron-hole and enhancing the light absorption capacity.

However, the cost of depositing noble metal on the surface of the semiconductor catalyst is high and the process is complex.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a bismuth-bismuth oxycarbonate composite photocatalyst as well as a preparation method and application thereof.

The invention is realized by the following technical scheme:

a preparation method of a bismuth-bismuth oxycarbonate composite photocatalyst comprises the following steps:

step 1: according to the formula (0.25-7.5): (1-3) molar ratio of Bi in the form of nano flower spheres₂O₂CO₃Powder and NaBH₄Dispersing in deionized water to obtain a precursor solution A;

according to the formula (0.5-7.5): (1-3) molar ratio of Bi in flake form₂O₂CO₃Powder and NaBH₄Dispersing in deionized water to obtain a precursor liquid B;

Preferably, the nano flower ball Bi in the step 1₂O₂CO₃The powder is obtained by the following steps:

Preferably, the flake Bi described in step 1₂O₂CO₃The powder is obtained by the following steps:

Preferably, step 1 is carried out first with every 0.001mol of Bi₂O₂CO₃Powder and NaBH 0.00025-0.0025 mol/per 0.00025₄Respectively adding the mixture into 10-30mL of deionized water, uniformly mixing to obtain a dispersion liquid a and a solution a correspondingly, and uniformly mixing the dispersion liquid a and the solution a according to the volume ratio of 1:1 to obtain a precursor liquid A;

Further, Bi as described for the precursor liquid A and the precursor liquid B₂O₂CO₃Powder and NaBH₄Adding into deionized water, stirring for 20-50min to obtain dispersion and solution.

Preferably, in step 2, the precursor solution A or B is stirred for 20 to 40min, and the resulting mixture is filtered.

Preferably, in the step 2, the washed filter cake is dried at 10-60 ℃ for 8-15h to obtain the nano flower-shaped spherical bismuth-bismuth oxycarbonate composite photocatalyst.

A bismuth-bismuth oxycarbonate composite photocatalyst prepared by the preparation method of any one of the bismuth-bismuth oxycarbonate composite photocatalysts.

Furthermore, in the bismuth-bismuth oxycarbonate composite photocatalyst, the elementary substance Bi is in a hexagonal system, and the space point group is R-3m (166).

The bismuth-bismuth oxycarbonate compound photocatalyst is applied to visible light and near infrared light degradation of antibiotics.

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

according to the preparation method of the bismuth-bismuth oxycarbonate composite photocatalyst, the semimetal bismuth (Bi) has the advantages of small band gap, easiness in obtaining, low cost, excellent electron transmission performance and the like, and the Surface Plasmon Resonance (SPR) effect can be used as a substitute of a noble metal material to promote electron-hole separation in the photocatalysis process, so that the nano flower-shaped spherical Bi is adopted₂O₂CO₃Or flake Bi₂O₂CO₃Powder as substrate, NaBH₄Is a chemical reducing agent, and is prepared into the nanometer flower-shaped spherical Bi-Bi in deionized water according to a certain proportion by a chemical reduction method₂O₂CO₃A composite photocatalyst is provided. Short reaction time, mild reaction condition, cheap and easily-obtained raw materials, and spherical or flaky Bi-Bi of the prepared nanoflower₂O₂CO₃The photocatalyst can realize the high-efficiency degradation of tetracycline under visible light and near infrared light, and has good application prospect in the degradation of antibiotics.

Drawings

FIG. 1 is an XRD pattern of the nano-flower spherical photocatalyst powder prepared by the present invention;

FIG. 2 is an XRD diagram of the nano-flower spherical photocatalyst powder prepared by the invention enlarged within the range of 20-40 degrees;

FIG. 3 is an SEM image of a photocatalyst prepared in comparative example 1 of the present invention;

FIG. 4 is an SEM image of a photocatalyst prepared in example 3 of the present invention;

FIG. 5 is a tetracycline removal curve of the nano-flower spherical photocatalyst prepared by the present invention under visible light;

FIG. 6 is a curve of tetracycline removal by the nano-flower spherical photocatalyst prepared by the present invention under near infrared light;

FIG. 7 is an XRD pattern of the photocatalyst flake powder prepared by the present invention;

FIG. 8 is an XRD pattern of the prepared flaky photocatalyst powder in the range of 20-40 deg;

FIG. 9 is an SEM image of a photocatalyst prepared according to comparative example 2 of the present invention;

FIG. 10 is an SEM image of a photocatalyst prepared in example 11 of the present invention;

FIG. 11 is a graph showing the tetracycline removal by the photocatalyst in pellet form prepared according to the present invention under visible light;

FIG. 12 is a graph showing the tetracycline removal by the photocatalyst in the form of a sheet prepared according to the present invention under near-infrared light.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

The invention relates to a nanometer flower-ball-shaped Bi-Bi₂O₂CO₃The preparation method of the composite photocatalyst specifically comprises the following steps:

step 1: mixing sodium citrate (Na) at a molar ratio of 1:2₃C₆H₅O₇·2H₂O) and Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring for 30-90min, regulating pH to 5-5.5 with NaOH solution, stirring for 30-90min to obtain precursor solution A containing Bi³⁺The concentration of (A) is 0.05-0.2 mol/L;

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 65-85%, heating to 180-class temperature 200 ℃ from room temperature in 45-60min, preserving heat for 18-24h, finishing the reaction, naturally cooling to room temperature, washing the obtained precipitate for 3 times by deionized water and absolute ethyl alcohol respectively, drying at the constant temperature of 65-80 ℃ for 10-16h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.00025-0.0025mol of NaBH₄Adding into 10-30mL deionized water, stirring for 20-50min to obtain NaBH₄A solution, precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 10-30mL of deionized water, and stirring for 20-50min to obtain Bi₂O₂CO₃Dispersion, precursor C;

and 5: under the condition of stirring, mixing the precursor liquid B and the precursor liquid C according to the volume ratio of 1:1, stirring for 20-40min, filtering the mixed liquid, washing a filter cake, and then drying at 10-60 ℃ for 8-15h to obtain Bi-Bi₂O₂CO₃A photocatalyst in which the simple substance Bi is a hexagonal system, the space point group is R-3m (166), Bi₂O₂CO₃Is tetragonal, has a point group of I4/mmm (139), and can be controlled by NaBH₄Content-adjusted Bi-Bi₂O₂CO₃Bi content in the photocatalyst.

The invention relates to a sheet Bi-Bi₂O₂CO₃The preparation method of the composite photocatalyst specifically comprises the following steps:

step 1: adding Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring in the solution for 30-90min to obtain precursor solution A, Bi (NO)₃)₃·5H₂The concentration of O is 0.5-1.5 mol.L^-1Mixing Na₂CO₃Dissolved in deionized water, Na₂CO₃The concentration of (A) is 0.05-1.5 mol.L^-1Stirring for 30-90min to obtain precursor liquid B;

step 2: mixing the precursor solution A and the precursor solution B in a volume ratio of 1:9, stirring for 10-40min, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, and drying at a constant temperature of 60 ℃ for 12h to obtain flaky Bi₂O₂CO₃；

And step 3: taking 0.019-0.0378g of NaBH₄(namely 0.0005-0.0025mol) is added into 10-30mL deionized water, and the mixture is stirred for 20-50min to obtain precursor liquid C;

and 4, step 4: 0.485g (i.e. 0.001mol) of Bi is taken₂O₂CO₃Adding the powder into 10-30mL of deionized water, and stirring for 20-50min to obtain a precursor solution D;

and 5: under the condition of stirring, mixing the precursor solution C and the precursor solution D according to the volume ratio of 1:1, stirring for 20-40min, filtering the mixed solution, washing a filter cake, and drying at 10-60 ℃ for 8-15h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

The following two Bi-Bi materials with different morphologies₂O₂CO₃The preparation method and conclusion of the composite photocatalyst are respectively explained.

The nano flower ball shaped Bi-Bi of the invention₂O₂CO₃The preparation method of the composite photocatalyst is carried out according to the following examples:

example 1:

step 1: 1.2g of Na₃C₆H₅O₇·2H₂O and 3.88g Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring the solution for 60min, adjusting the pH value of the solution to 5.4 by using NaOH solution, and stirring the solution for 60min to obtain precursor solution A;

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 80%, heating to 180 ℃ from room temperature within 60min, preserving heat for 18h to finish the reaction, naturally cooling to room temperature, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, drying at 70 ℃ for 12h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.00025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution C;

and 5: under the condition of stirring, mixing the precursor liquid B and the precursor liquid C according to the volume ratio of 1:1, stirring for 30min, filtering the mixed liquid, washing a filter cake, and drying at 50 ℃ for 10h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

Example 2:

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 80% for 60minHeating from room temperature to reaction temperature of 180 ℃, preserving heat for 18h, finishing the reaction, naturally cooling to room temperature, washing the obtained precipitate for 3 times by deionized water and absolute ethyl alcohol respectively, drying at constant temperature of 70 ℃ for 12h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.0005mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution C;

Example 3:

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 80%, heating to a reaction temperature of 180 ℃ from room temperature within 60min, preserving heat for 18h to finish the reaction, naturally cooling to room temperature, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, drying at a constant temperature of 70 ℃ for 12h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.00075mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution C;

Example 4:

and step 3: taking 0.0025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution C;

Example 5:

step 1: 1.2g of Na₃C₆H₅O₇·2H₂O and 3.88g Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring the solution for 30min, adjusting the pH value of the solution to 5.4 by using NaOH solution, and stirring the solution for 60min to obtain precursor solution A;

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 65%, heating to a reaction temperature of 190 ℃ from room temperature within 50min, keeping the temperature for 19h, finishing the reaction, naturally cooling to room temperature, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, drying at a constant temperature of 65 ℃ for 16h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.0025mol of NaBH₄Adding into 10mL deionized water, stirring for 20min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 30mL of deionized water, and stirring for 50min to obtain a precursor solution C;

and 5: under the condition of stirring, mixing the precursor liquid B and the precursor liquid C according to the volume ratio of 1:1, stirring for 30min, filtering the mixed liquid, washing a filter cake, and drying at 60 ℃ for 8h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

Example 6:

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 80%, heating to a reaction temperature of 180 ℃ from room temperature within 60min, preserving heat for 20h, finishing the reaction, naturally cooling to room temperature, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, drying at a constant temperature of 70 ℃ for 12h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.0025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution C;

and 5: under the condition of stirring, mixing the precursor liquid B and the precursor liquid C according to the volume ratio of 1:1, stirring for 30min, filtering the mixed liquid, washing a filter cake, and drying at 15 ℃ for 12h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

Example 7:

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 80%, heating to a reaction temperature of 180 ℃ from room temperature within 60min, preserving heat for 22h, finishing the reaction, naturally cooling to room temperature, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, drying at a constant temperature of 70 ℃ for 12h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.0025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution C;

and 5: under the condition of stirring, mixing the precursor liquid B and the precursor liquid C according to the volume ratio of 1:1, stirring for 30min, filtering the mixed liquid, washing a filter cake, and drying at 20 ℃ for 8h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

Example 8:

step 1: 1.2g of Na₃C₆H₅O₇·2H₂O and 3.88g Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring the solution for 90min, adjusting the pH value of the solution to 5.4 by using NaOH solution, and stirring the solution for 60min to obtain precursor solution A;

step 2: placing the precursor solution A in a hydrothermal reaction kettle with a reaction filling ratio of 85%, heating to a reaction temperature of 200 ℃ from room temperature within 45min, keeping the temperature for 24h, finishing the reaction, naturally cooling to room temperature, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, drying at a constant temperature of 80 ℃ for 10h, and grinding to obtain Bi₂O₂CO₃Powder;

and step 3: taking 0.0025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor liquid B;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL deionized water, stirring for 30min to obtain precursor solutionC；

And 5: under the condition of stirring, mixing the precursor liquid B and the precursor liquid C according to the volume ratio of 1:1, stirring for 30min, filtering the mixed liquid, washing a filter cake, and drying at 10 ℃ for 15h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

Comparative example 1:

FIG. 1 is an XRD pattern of a photocatalyst prepared according to the present invention, in which a to e are XRD patterns of photocatalyst powders prepared according to comparative example 1 and examples 1 to 4, respectively, in this order. From the XRD patterns of the powders prepared in examples 1 to 4, elementary Bi and Bi were observed₂O₂CO₃The diffraction peak of (2 θ) corresponds to Bi having a tetragonal structure, respectively, 15.0 °, 27.8 °, 35.3 °, 38.2 °, 49.5 °, and 67.2 °₂O₂CO₃Diffraction peaks of (002), (011), (013), (110), (114), and (123) crystal planes of (PDF No. 41-1488); diffraction peaks corresponding to the (012), (104), (110) and (202) crystal planes of the hexagonal phase Bi (PDF No.44-1246) appear at 2 θ of 31.7 °, 44.4 °, 46.3 ° and 57.2 °, indicating that Bi-Bi is successfully prepared₂O₂CO₃A photocatalyst.

FIG. 2 is an XRD pattern of the photocatalyst powder prepared in the present invention enlarged in the range of 20 to 40, and a to e are XRD patterns of the photocatalyst powder prepared in comparative example 1 and examples 1 to 4 enlarged in the range of 20 to 40, respectively. From the XRD pattern, NaBH in the presence of a reducing agent can be observed₄Then, the characteristic peak of Bi in XRD diffraction peaks is gradually clarifiedObviously, the successful preparation of Bi-Bi is demonstrated₂O₂CO₃Photocatalyst and can be prepared by controlling NaBH₄Content-adjusted Bi-Bi₂O₂CO₃Bi content in the photocatalyst.

FIGS. 3 and 4 are SEM images of the photocatalysts prepared in comparative example 1 and example 3, respectively, and pure-phase Bi can be observed₂O₂CO₃And Bi-Bi prepared in example 3₂O₂CO₃The photocatalyst is in a nanometer flower ball shape, and the introduction of Bi is proved to be Bi-Bi₂O₂CO₃The morphology of the photocatalyst has no significant influence.

FIG. 5 is a graph showing the removal curve of 20mg/L tetracycline from the catalyst powder prepared in accordance with the present invention under irradiation with visible light, and a to e are the removal curves of tetracycline from the powders prepared in comparative example 1 and examples 1 to 4, respectively, in the order named, and C/C on the ordinate₀Is the ratio of the concentration of tetracycline after degradation to its initial concentration. As seen from the figure, after irradiation with visible light for 120min, Bi-Bi prepared in comparative example 1 and examples 1 to 4₂O₂CO₃The removal rate of the photocatalyst to the tetracycline is 58%, 68%, 72% and 64% respectively. Prepared Bi-Bi₂O₂CO₃The photocatalyst shows obviously higher than pure phase Bi₂O₂CO₃Photocatalytic Properties of catalyst, wherein Bi-Bi prepared in example 3₂O₂CO₃The removal rate of the photocatalyst to the tetracycline can reach 72 percent.

FIG. 6 is a graph showing the removal curve of 20mg/L tetracycline from the catalyst powder prepared in accordance with the present invention under irradiation with near-infrared light, and a to e are the removal curves of tetracycline from the powders prepared in comparative example 1 and examples 1 to 4, respectively, in order, and C/C on the ordinate₀Is the ratio of the concentration of tetracycline after degradation to its initial concentration. As seen from the figure, after 120min of near-infrared light irradiation, Bi-Bi prepared in comparative example 1 and examples 1-4₂O₂CO₃The removal rate of the photocatalyst to the tetracycline is respectively 38%, 52%, 66%, 62% and 63%. Prepared Bi-Bi₂O₂CO₃The photocatalyst shows obviously higher than pure phase Bi under near infrared light₂O₂CO₃Photocatalytic Properties of the catalyst, wherein Bi-Bi prepared in example 2₂O₂CO₃The removal rate of the photocatalyst to the tetracycline can reach 66%.

The flaky Bi-Bi of the invention₂O₂CO₃The preparation method of the composite photocatalyst is carried out according to the following examples:

example 9:

step 1: adding Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring in the solution for 60min to obtain precursor solution A, adding Na₂CO₃Dissolved in deionized water, Bi (NO)₃)₃·5H₂The concentration of O is 1 mol. L^-1，Na₂CO₃Has a concentration of 0.89 mol.L^-1Stirring for 60min to obtain precursor liquid B;

step 2: mixing the precursor solution A and the precursor solution B in a volume ratio of 1:9, stirring for 30min, washing the obtained precipitate with deionized water and absolute ethyl alcohol for 3 times respectively, and drying at a constant temperature of 60 ℃ for 12h to obtain flaky Bi₂O₂CO₃；

And step 3: taking 0.0005mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution D;

and 5: under the condition of stirring, mixing the precursor solution C and the precursor solution D according to the volume ratio of 1:1, stirring for 30min, filtering the mixed solution, washing a filter cake, and drying at 50 ℃ for 10h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

Example 10:

And step 3: taking 0.00075mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution D;

Example 11:

And step 3: taking 0.0025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution D;

and 5: mixing the precursor solutions C and D at a volume ratio of 1:1 under stirring, stirring for 30min, filtering the mixed solution, washing the filter cakeWashing, and drying at 50 deg.C for 10h to obtain Bi-Bi₂O₂CO₃A photocatalyst.

Example 12:

step 1: adding Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring in the solution for 50min to obtain precursor solution A, adding Na₂CO₃Dissolved in deionized water, Bi (NO)₃)₃·5H₂The concentration of O is 1 mol. L^-1，Na₂CO₃Has a concentration of 0.89 mol.L^-1Stirring for 50min to obtain precursor liquid B;

And step 3: taking 0.0025mol of NaBH₄Adding into 15mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 15mL of deionized water, and stirring for 30min to obtain a precursor solution D;

Example 13:

step 1: adding Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring in the solution for 70min to obtain precursor solution A, adding Na₂CO₃Dissolved in deionized water, Bi (NO)₃)₃·5H₂The concentration of O is 0.75 mol.L^-1，Na₂CO₃Has a concentration of 0.89 mol.L^-1Stirring for 70min to obtain precursor liquid B;

step 2: mixing the precursor solution A and the precursor solution B at a volume ratio of 1:9, stirring for 30min, washing the obtained precipitate with deionized water and anhydrous ethanol for 3 times, and drying at 60 deg.C for 12 hr to obtainTo flake Bi₂O₂CO₃；

And step 3: taking 0.0025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution D;

Example 14:

step 1: adding Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring in the solution for 50min to obtain precursor solution A, adding Na₂CO₃Dissolved in deionized water, Bi (NO)₃)₃·5H₂The concentration of O is 1 mol. L^-1，Na₂CO₃Has a concentration of 1 mol. L^-1Stirring for 50min to obtain precursor liquid B;

And step 3: taking 0.0025mol of NaBH₄Adding into 25mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 25mL of deionized water, and stirring for 30min to obtain a precursor solution D;

Example 15:

step 1: adding Bi (NO)₃)₃·5H₂O in HNO₃Stirring in the solution for 50min to obtain precursor solution A, adding Na₂CO₃Dissolved in deionized water, Bi (NO)₃)₃·5H₂The concentration of O is 1 mol. L^-1，Na₂CO₃Has a concentration of 0.75 mol. L^-1Stirring for 50min to obtain precursor liquid B;

And step 3: taking 0.0025mol of NaBH₄Adding into 20mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 20mL of deionized water, and stirring for 30min to obtain a precursor solution D;

Example 16:

step 1: adding Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring in the solution for 70min to obtain precursor solution A, adding Na₂CO₃Dissolved in deionized water, Bi (NO)₃)₃·5H₂The concentration of O is 1.2 mol.L^-1，Na₂CO₃Has a concentration of 1 mol. L^-1Stirring for 70min to obtain precursor liquid B;

And step 3: taking 0.0025mol of NaBH₄Adding into 15mL deionized water, stirring for 30min to obtain precursor solution C;

and 4, step 4: 0.001mol of Bi is taken₂O₂CO₃Adding the powder into 15mL of deionized water, and stirring for 30min to obtain a precursor solution D;

Comparative example 2:

step 1: adding Bi (NO)₃)₃·5H₂O dissolved in HNO₃Stirring in the solution for 30-90min to obtain precursor solution A, adding Na₂CO₃Dissolved in deionized water, Bi (NO)₃)₃·5H₂The concentration of O is 1 mol. L^-1，Na₂CO₃Has a concentration of 0.89 mol.L^-1Stirring for 30-90min to obtain precursor liquid B;

FIG. 7 is an XRD pattern of the photocatalyst prepared in the present invention, wherein a-c are XRD patterns of the photocatalyst powders prepared in accordance with examples 9-11, respectively. From the XRD patterns of the powders prepared in examples 9 to 11, elementary Bi and Bi were observed₂O₂CO₃The diffraction peaks of (a) 2 θ, 15.0 °, 27.8 °, 35.3 °, 38.2 °, 49.5 °, and 67.2 °, correspond to Bi, respectively₂O₂CO₃Diffraction peaks of (002), (011), (013), (110), (114), and (123) crystal planes of (PDF No. 41-1488); diffraction peaks corresponding to the (012), (104), (110), and (202) crystal planes of Bi (PDF No.44-1246) appear at 2 θ of 31.7 °, 44.4 °, 46.3 °, and 57.2 °, wherein the simple substance of Bi belongs to the hexagonal system, and the spatial point group is R-3m (166); bi₂O₂CO₃Belongs to a tetragonal system, and the space point group is I4/mmm (139), which indicates that the Bi-Bi is successfully prepared₂O₂CO₃A photocatalyst.

FIG. 8 shows that the photocatalyst powder prepared by the invention is enlarged within the range of 20-40 DEGXRD patterns, in which a-c are XRD patterns enlarged in the range of 20-40 deg. for the photocatalyst powders prepared according to examples 9-11, respectively. From the XRD pattern, NaBH in the presence of a reducing agent can be observed₄Then, the characteristic peak of Bi in XRD diffraction peaks is gradually obvious, which indicates that Bi-Bi is successfully prepared₂O₂CO₃Photocatalyst and can be prepared by controlling NaBH₄Content-adjusted Bi-Bi₂O₂CO₃Bi content in the photocatalyst.

FIGS. 9 and 10 are SEM images of the photocatalysts prepared in comparative example 2 and example 11, respectively, and pure-phase Bi can be observed₂O₂CO₃And Bi-Bi prepared in example 11₂O₂CO₃The photocatalyst has a flaky shape, and the introduction of Bi is proved to be to Bi-Bi₂O₂CO₃The morphology of the photocatalyst has no significant influence.

FIG. 11 is a graph showing the removal curve of 20mg/L tetracycline by the catalyst powder prepared in the present invention under irradiation of visible light, and a to d are the removal curves of tetracycline by the photocatalyst powders prepared in examples 9 to 11 and comparative example 2, respectively, and C/C on the ordinate₀Is the ratio of the concentration of tetracycline after degradation to its initial concentration. As seen from the figure, after irradiation with visible light for 120min, Bi-Bi prepared in comparative example 2 and examples 9 to 11₂O₂CO₃The removal rate of the photocatalyst to tetracycline is 51%, 50%, 53% and 60% respectively. Prepared Bi-Bi₂O₂CO₃The photocatalyst shows obviously higher than pure phase Bi₂O₂CO₃Photocatalytic Properties of catalyst, wherein Bi-Bi prepared in example 11₂O₂CO₃The removal rate of the photocatalyst to the tetracycline can reach 60%.

FIG. 12 is a graph showing the removal curve of 20mg/L tetracycline from the catalyst powder prepared in accordance with the present invention under irradiation of near-infrared light, and a to d are the removal curves of tetracycline from the photocatalyst powders prepared in accordance with examples 9 to 11 and comparative example 2, respectively, C/C on the ordinate₀Is the ratio of the concentration of tetracycline after degradation to its initial concentration. As seen from the figure, after irradiation with near-infrared light for 120min, Bi-Bi prepared in comparative example 2 and examples 9 to 11₂O₂CO₃The removal rates of the photocatalyst to tetracycline are 39%, 43%, 41% and 54%, respectively. Prepared Bi-Bi₂O₂CO₃The photocatalyst shows obviously higher than pure phase Bi₂O₂CO₃Photocatalytic Properties of catalyst, wherein Bi-Bi prepared in example 11₂O₂CO₃The removal rate of the photocatalyst to the tetracycline can reach 54 percent.

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