Z-type Bi prepared based on in-situ synthesis method3O4Cl/Bi2MoO6Composite photocatalyst and application thereof
阅读说明：本技术 基于原位合成法制备的Z型Bi3O4Cl/Bi2MoO6复合光催化剂及其应用 (Z-type Bi prepared based on in-situ synthesis method3O4Cl/Bi2MoO6Composite photocatalyst and application thereof ) 是由 张朝红 柴嘉男 王丽涛 王君 么鸿砜 房大维 于 2021-01-28 设计创作，主要内容包括：本发明涉及基于原位合成法制备的Z型Bi-3O-4Cl/Bi-2MoO-6复合光催化剂及其应用。首先将Bi(NO-3)-3·5H-2O溶液和NH-4Cl溶液充分搅拌,混合均匀后置于不锈钢高压反应釜中,放于烘箱中160℃反应12h,所得产物离心、干燥、研磨后,于500℃下煅烧5h,得到目标产物Bi-3O-4Cl纳米微粒。本发明以Bi-3O-4Cl为前驱体进行原位反应生成Bi-2MoO-6,构建Z型Bi-3O-4Cl/Bi-2MoO-6复合光催化剂,在可见光作用下可高效光催化降解水中有机污染物。(The invention relates to Z-type Bi prepared based on an in-situ synthesis method 3 O 4 Cl/Bi 2 MoO 6 A composite photocatalyst and application thereof. First Bi (NO) 3 ) 3 ·5H 2 O solution and NH 4 Fully stirring the Cl solution, uniformly mixing, placing the mixture into a stainless steel high-pressure reaction kettle, placing the stainless steel high-pressure reaction kettle into a drying oven for reaction at 160 ℃ for 12 hours, centrifuging, drying and grinding the obtained product, and calcining the product at 500 ℃ for 5 hours to obtain a target product Bi 3 O 4 Cl nanoparticles. The invention uses Bi 3 O 4 Cl is taken as a precursor to carry out in-situ reaction to generate Bi 2 MoO 6 Construction of Z-type Bi 3 O 4 Cl/Bi 2 MoO 6 The composite photocatalyst can efficiently emit light under the action of visible lightCatalyzing and degrading organic pollutants in water.)
1. Z-type Bi prepared based on in-situ synthesis method3O4Cl/Bi2MoO6A composite photocatalyst is characterized in that Bi is present in a particle quantity ratio3O4Cl:Bi2MoO6＝(0.5-10):1。
2. The Z-type Bi prepared based on the in-situ synthesis method according to claim 13O4Cl/Bi2MoO6The composite photocatalyst is characterized in that the preparation method comprises the following steps: taking Bi3O4Cl and Na2MoO4·2H2O is dissolved in ethylene glycol, and then Bi is added3O4Cl suspension and Na2MoO4Fully stirring the solution, uniformly mixing, placing the solution in a stainless steel high-pressure reaction kettle, placing the solution in a drying oven, reacting for 24 hours at 160 ℃, centrifuging and drying the obtained product, grinding the product, and calcining for 5 hours at 500 ℃ to obtain a target product Bi3O4Cl/Bi2MoO6。
3. The Z-type Bi prepared based on the in-situ synthesis method according to claim 13O4Cl/Bi2MoO6The composite photocatalyst is characterized in that the Bi3O4The preparation method of Cl comprises the following steps: adding Bi (NO)3)3·5H2Dissolving O in ethylene glycol, magnetically stirring, and adding NH4Continuously stirring the Cl aqueous solution for 20min, transferring the Cl aqueous solution into a Teflon stainless steel high-pressure reaction kettle, putting the kettle into an oven, reacting for 12h at 160 ℃, cooling to room temperature, centrifugally collecting precipitate, washing with distilled water, drying, and calcining for 5h at 500 ℃ to obtain Bi3O4And (3) Cl nanoparticles.
4. Z-form Bi prepared based on in-situ synthesis method according to any one of claims 1 to 33O4Cl/Bi2MoO6The composite photocatalyst is applied to degrading antibiotics under visible light.
5. Use according to claim 4, characterized in that the method is as follows: adding the Z-type Bi prepared based on the in-situ synthesis method according to any one of claims 1 to 3 into a solution containing antibiotics3O4Cl/Bi2MoO6And (3) irradiating the composite photocatalyst for 2-3h under sunlight.
6. The use of claim 5, wherein the Z-form Bi is prepared by in situ synthesis3O4Cl/Bi2MoO6The adding amount of the composite photocatalyst is 0.5-2.0 g/L.
7. The use of any one of claims 4 to 6, wherein the antibiotic is norfloxacin.
Technical Field
The present invention belongs toIn the field of photocatalysts, in particular to Z-shaped Bi synthesized by a hydrothermal method and an in-situ synthesis method3O4Cl/Bi2MoO6A composite photocatalyst and application thereof in degrading organic pollutants in water under visible light.
Background
With the rapid development of modern economy, the excessive consumption of various non-renewable energy sources by people makes the non-renewable energy sources more and more scarce, and simultaneously, a large amount of pollutants are generated to harm the environment. Therefore, new energy is increasingly paid attention and researched, and the development of the new energy is an urgent task. In recent years, advanced oxidation technologies, especially photocatalytic technologies, have been studied more and more intensively, and have become effective means for solving energy crisis and degrading pollutants. Conventional photocatalysts (e.g. TiO)2ZnO, etc.) cannot be well utilized due to low utilization rate of sunlight, high electron hole recombination rate, etc. Therefore, the improvement on the existing basis is a feasible method for improving the photocatalytic performance.
Bismuth-based photocatalysts are catalysts which take metal bismuth and other bismuth compounds as main components, have special layered structures and forbidden bandwidth with proper size, have the characteristics of stable chemical properties, low cost, simple preparation process and the like, and have good degradation capability on organic pollutants (antibiotics, dyes and the like) in water, so that the bismuth-based photocatalysts attract more and more attention.
Disclosure of Invention
The object of the present invention is Bi3O4Taking Cl as a precursor, and synthesizing Z-type Bi through an in-situ synthesis method3O4Cl/Bi2MoO6The composite photocatalyst further widens the photoresponse range of the semiconductor photocatalyst, obviously reduces the electron and hole recombination rate, and obviously improves the catalytic activity of the photocatalyst.
Another object of the present invention is to utilize Z-type Bi3O4Cl/Bi2MoO6The composite photocatalyst catalyzes and degrades antibiotics in water.
The technical scheme adopted by the invention is as follows: based on in situ synthesisPrepared Z-type Bi3O4Cl/Bi2MoO6A composite photocatalyst, Bi in a particle number ratio3O4Cl:Bi2MoO6＝(0.5-10):1。
Further, the Z-type Bi prepared based on the in-situ synthesis method3O4Cl/Bi2MoO6The preparation method of the composite photocatalyst comprises the following steps: taking Bi3O4Cl and Na2MoO4·2H2O is dissolved in ethylene glycol, and then Bi is added3O4Cl suspension and Na2MoO4Fully stirring the solution, uniformly mixing, placing the solution in a stainless steel high-pressure reaction kettle, placing the solution in a drying oven, reacting for 24 hours at 160 ℃, centrifuging and drying the obtained product, grinding the product, and calcining for 5 hours at 500 ℃ to obtain a target product Bi3O4Cl/Bi2MoO6。
Further, the Z-type Bi prepared based on the in-situ synthesis method3O4Cl/Bi2MoO6A composite photocatalyst of said Bi3O4The preparation method of Cl comprises the following steps: adding Bi (NO)3)3·5H2Dissolving O in ethylene glycol, magnetically stirring, and adding NH4Continuously stirring the Cl aqueous solution for 20min, transferring the Cl aqueous solution into a Teflon stainless steel high-pressure reaction kettle, putting the kettle into an oven, reacting for 12h at 160 ℃, cooling to room temperature, centrifugally collecting precipitate, washing with distilled water, drying, and calcining for 5h at 500 ℃ to obtain Bi3O4And (3) Cl nanoparticles.
The Z-type Bi prepared based on the in-situ synthesis method provided by the invention3O4Cl/Bi2MoO6The composite photocatalyst is applied to degrading antibiotics under visible light.
Further, the method is as follows: adding the Z-type Bi prepared based on the in-situ synthesis method into a solution containing antibiotics3O4Cl/Bi2MoO6And (3) irradiating the composite photocatalyst for 2-3h under sunlight.
Further, Z-type Bi prepared based on in-situ synthesis method3O4Cl/Bi2MoO6The adding amount of the composite photocatalyst is 0.5-2.0 g/L.
Further, the antibiotic is norfloxacin.
The invention has the beneficial effects that: in the invention, Z-type Bi3O4Cl/Bi2MoO6The composite photocatalyst is prepared by a hydrothermal method and an in-situ synthesis method, the preparation process is simple and convenient, and the prepared catalyst has high purity. Namely, Bi is synthesized firstly3O4Cl monomer and taking it as precursor to synthesize Bi in situ2MoO6The two substances form a Z-shaped structure, so that the photoresponse range is greatly widened, the combination of photo-generated electrons and holes is reduced, and the photocatalytic activity is further improved.
Drawings
FIG. 1 shows Bi3O4X-ray diffraction pattern of Cl.
FIG. 2 is Bi2MoO6X-ray diffraction pattern of (a).
FIG. 3 is Bi3O4Cl/Bi2MoO6X-ray diffraction pattern of (a).
FIG. 4 shows Bi3O4Cl/Bi2MoO6Scanning electron microscopy of (a).
FIG. 5 shows Bi3O4Cl/Bi2MoO6Transmission electron microscopy images of (a).
Figure 6 is a graph of the ultraviolet absorption of norfloxacin solution.
Detailed Description
Example 1
Z-type Bi3O4Cl/Bi2MoO6The preparation method of the composite photocatalyst (I) comprises the following steps:
1) preparation of Bi by hydrothermal method3O4Cl monomer: first, 0.97g of Bi (NO) was accurately weighed3)3·5H2O is placed in a clean beaker, then 20mL of ethylene glycol is measured and added, and the mixture is stirred magnetically for 10min to be dissolved completely. Simultaneously, accurately measuring 0.036g of NH4Cl was placed in another clean beaker, 50mL of distilled water was added thereto, and it was dissolved by continuous stirring, and then both were put intoThe solution was mixed and stirred for 20 min. Then, the mixture was transferred to a 100ml Teflon stainless steel autoclave and placed in an oven to react at 160 ℃ for 12 hours. Then, the precipitate was cooled to room temperature, collected by centrifugation, washed three times with distilled water, and dried at 80 ℃ for 12 hours. Then calcining the solid powder in a muffle furnace at 500 ℃ for 5h, cooling to room temperature, fully grinding, and storing in a closed container to obtain Bi3O4And (3) Cl nanoparticles.
2) Preparation of Bi by in situ Synthesis3O4Cl/Bi2MoO6The composite photocatalyst comprises: first, 6 parts by weight of Bi each 0.3632g were weighed3O4The Cl solid powders were dissolved in 20ml of ethylene glycol, magnetically stirred for 10min, and then 6 parts by weight of Na were weighed as 0.1688g, 0.1578g, 0.1396g, 0.1251g, 0.1037g and 0.0726g2MoO4·2H2O is respectively dissolved in 10ml of ethylene glycol, the mixture is magnetically stirred for 10min, and then 6 parts of sodium molybdate solution is respectively poured into Bi3O4In the Cl suspension, the mixture is stirred magnetically for 20min to be mixed evenly. And then transferring the mixture into a 50ml Teflon stainless steel high-pressure reaction kettle, marking, putting the kettle into an oven, reacting for 24 hours at 160 ℃, taking out the kettle, naturally cooling to room temperature, centrifuging, collecting precipitate, washing with deionized water for three times, and drying for 12 hours at 60 ℃. The solid powder was then calcined in a muffle furnace at 500 ℃ for 5 h. Finally obtaining solid powder, fully grinding the solid powder, storing the powder in a dry closed container, and finally marking the powder as Bi respectively3O4Cl/Bi2MoO6(0.5:1)、Bi3O4Cl/Bi2MoO6(1:1)、Bi3O4Cl/Bi2MoO6(2:1)、Bi3O4Cl/Bi2MoO6(3:1)、Bi3O4Cl/Bi2MoO6(5:1) and Bi3O4Cl/Bi2MoO6(10:1) nanocomposite (numerical values in parentheses represent Bi)3O4Cl and Bi2MoO6The number ratio of particles) of (c).
(II) comparative example
Preparation of Bi2MoO6Monomer (b): accurately weigh 1.74mmol (0).8433g)Bi(NO3)3·5H2O and 0.87mmol (0.2105g) Na2MoO4·2H2O, each dissolved in 10mL of Ethylene Glycol (EG), and the mixture was stirred to dissolve all of O. Then, the two solutions were mixed and stirred well for 20 min. Then transferred to a 50mL Teflon stainless steel autoclave and placed in an oven to react at 160 ℃ for 20 h. Then taking out and cooling to room temperature, centrifuging and collecting precipitate, washing with deionized water for three times, and drying at 60 ℃ for 12 h. Finally obtaining yellow solid powder Bi2MoO6And (3) fully grinding the nano particles, and then filling the ground nano particles into a dry closed container for later use.
(III) characterization of the catalyst
FIG. 1 shows Bi3O4XRD pattern of Cl nanoparticles, Bi is clearly seen in FIG. 13O4Characteristic peak of Cl, and is consistent with that of standard card (JCPDS NO.36-0760), and the result shows that Bi is successfully prepared3O4Cl nanoparticles.
FIG. 2 is Bi2MoO6XRD pattern of nanoparticles, Bi is clearly seen in FIG. 22MoO6The characteristic peaks of (a) are in one-to-one correspondence with the standard cards (JCPDS NO.21-0102), thereby proving that Bi2MoO6And (4) successfully synthesizing.
FIG. 3 shows Z-form Bi3O4Cl/Bi2MoO6XRD pattern of composite photocatalyst, Bi in the pattern3O4Cl and Bi2MoO6All the characteristic peaks are shown, and the results show that Bi3O4Cl/Bi2MoO6The composite photocatalyst is successfully prepared.
FIG. 4 shows Bi3O4Cl/Bi2MoO6Scanning electron microscopy of (a). The bulk Bi is clearly seen in FIG. 43O4Cl and small spherical Bi2MoO6Thus the test result shows that the Z type Bi3O4Cl/Bi2MoO6The composite photocatalyst is successfully prepared.
FIG. 5 shows Bi3O4Cl/Bi2MoO6Transmission electron microscopy images of (a). It can be clearly understood from the figureThe crystal lattice stripes and the widths in two different directions are clearly seen, and the comparison proves that Bi is3O4Cl and Bi2MoO6Nanoparticles, the results thus demonstrate Bi3O4Cl/Bi2MoO6And (4) successfully compounding.
EXAMPLE 2Z-form Bi3O4Cl/Bi2MoO6Influence of composite photocatalyst on degradation of norfloxacin
Influence of (I) different catalysts on degradation rate of norfloxacin
The experimental method comprises the following steps: 0.02g of Bi was weighed out separately3O4Cl、Bi2MoO6And Bi3O4Cl/Bi2MoO6(1:1) the photocatalyst was added to a quartz tube, and 20mL of an initial 10mg/L Norfloxacin (NFX) aqueous solution was added thereto to conduct the photocatalytic degradation experiment. After 2.5h of irradiation with visible light, 10mL of NFX solution was removed from the quartz tube and centrifuged. The supernatant was then filtered through a 0.45 μm filter to remove the remaining photocatalyst particles. Then measuring the ultraviolet absorbance of the supernatant at 200-800nm, substituting the ultraviolet absorbance into a standard curve formula, and finally calculating the degradation rate of NFX. The results are shown in Table 1 and FIG. 6.
Percent degradation rate (%) (1-C/C)0) X 100% (wherein C)0: the concentration of the stock solution; c: concentration of sample).
FIG. 6 is a UV-Vis spectrum of Norfloxacin (NFX) degradation under different conditions under visible light irradiation. As can be seen from the figure, the three catalysts all have degradation effect on NFX, wherein, under the irradiation of visible light, Z-type Bi3O4Cl/Bi2MoO6The catalyst has the most obvious effect on the degradation of NFX solution.
TABLE 1 Effect of different catalysts on norfloxacin degradation
Table 1 shows Bi3O4Cl、Bi2MoO6And Bi3O4Cl/Bi2MoO6Three photocatalysts have different effects on photocatalytic degradation of norfloxacin. As can be seen from Table 1, Bi prepared by the present invention under the condition of 2.5h of irradiation time3O4Cl/Bi2MoO6The composite photocatalyst has the highest degradation rate which reaches 77.1%.
Influence of (II) particle number ratio on norfloxacin degradation rate
The experimental method comprises the following steps: measuring 20mL of norfloxacin solution with initial concentration of 10mg/L, respectively placing the norfloxacin solution into 6 special quartz tubes, and respectively adding 0.02g of Bi with different particle number ratios3O4Cl/Bi2MoO6The composite photocatalyst is irradiated under visible light for 2.5h, and then 10mL of NFX solution is taken out of a quartz tube and centrifuged. The supernatant was then filtered through a 0.45 μm filter to remove the remaining photocatalyst particles. Then measuring the ultraviolet absorbance of the supernatant at 200-800nm, substituting the ultraviolet absorbance into a standard curve formula, and finally calculating the degradation rate of NFX. The results are shown in Table 2.
TABLE 2 influence of the particle number ratio on the norfloxacin degradation effect
As can be seen from Table 2, Z-form Bi was obtained at a particle number ratio of 1:13O4Cl/Bi2MoO6The photocatalyst has higher degradation rate which is 77.1 percent.
(III) influence of different adding amounts of catalyst on degradation rate of norfloxacin
The experimental method comprises the following steps: measuring 20mL of norfloxacin solution with initial concentration of 10mg/L, respectively placing the norfloxacin solution into 4 special quartz tubes, and respectively adding different doses of Bi3O4Cl/Bi2MoO6(particle ratio: 1) the composite photocatalyst was irradiated with visible light for 2.5 hours, and then 10mL of NFX solution was taken out from the quartz tube and centrifuged. Then, the supernatant was filtered through a 0.45 μm filter to remove the remaining photocatalyst fine particlesAnd (4) granulating. Then measuring the ultraviolet absorbance of the supernatant at 200-800nm, substituting the ultraviolet absorbance into a standard curve formula, and finally calculating the degradation rate of NFX. The results are shown in Table 3.
TABLE 3 Effect of different amounts of photocatalyst added on degradation of norfloxacin
As can be seen from Table 3, the degradation rate of NFX increased gradually with increasing catalyst addition. When the catalyst addition amount is 2.0g/L, Bi3O4Cl/Bi2MoO6The degradation rate of the composite catalyst to NFX was 85.2%.
In the above examples, norfloxacin was used as the organic contaminant, but norfloxacin is not a limitation to the antibiotics degraded by the present invention, and the method of the present invention is suitable for degrading any antibiotics, such as sulfanilamide, tetracycline, etc.