A Bi 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst and preparation method and application thereof
By constructing a Bi12O17Cl2/ZnCdS heterojunction photocatalyst, the problems of photocorrosion and stability of CdS-based photocatalysts in the degradation of bisphenol A were solved, achieving highly efficient visible light photocatalytic degradation. The material maintained good performance during multiple uses.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 中国市政工程西北设计研究院有限公司
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-22
AI Technical Summary
Existing CdS-based photocatalysts suffer from severe photocorrosion, poor cycle stability, rapid recombination of photogenerated carriers, and low quantum efficiency when degrading bisphenol A, resulting in limited visible light photocatalytic efficiency.
A Bi12O17Cl2/ZnCdS heterojunction photocatalyst was constructed. By combining Bi12O17Cl2 and ZnCdS, the layered structure and excellent visible light response of Bi12O17Cl2 are matched with the band structure of ZnCdS to promote the efficient separation and migration of photogenerated carriers, reduce the recombination rate of electron-hole pairs, broaden the light absorption range, and enhance the stability of the material.
It significantly improved the degradation rate and mineralization efficiency of bisphenol A, enhanced visible light utilization efficiency, material stability, and recyclability, achieving a degradation rate of 98% and maintaining good performance after five cycles.
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Figure CN121551035B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalysts, specifically relating to a Bi 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst, its preparation method, and its application. Background Technology
[0002] Endocrine disruptors (EDCs) are diverse, including but not limited to bisphenol A (BPA), phthalates (such as DBP and DEHP), polychlorinated biphenyls (PCBs), and numerous pesticides and heavy metals. These compounds are ubiquitous in plastics, cosmetics, pesticides, industrial chemicals, and food additives. Environmental EDCs are widely distributed in the air, water, and soil, originating partly from biological and human ingestion and emissions, and partly from physicochemical processes such as industrial and agricultural wastewater discharge and fossil fuel combustion. These substances can enter the human body through respiration, ingestion, and skin contact.
[0003] Among numerous EDCs (Electronic Chemicals), Bisphenol A (BPA) is a typical example. It is a widely used epoxy resin chemical used globally in food packaging, thermal paper, and dental materials. In vivo absorption of BPA can lead to metabolic problems, including sex-specific neurodevelopmental disorders, immunotoxicity, neurotoxicity, and interference with cell signaling. With increasing BPA use, its environmental exposure levels are also rising. Due to its stable molecular structure, difficulty in degradation, and potential toxicity, BPA can accumulate through the food chain, posing a threat to environmental safety and mammalian health, disrupting hormonal balance, and causing endocrine system disorders. Because of its high stability in the environment, difficulty in natural degradation, accumulation in organisms, and interference with the endocrine system, BPA emissions have become a significant challenge in water environment management. Traditional physical and chemical treatment methods, such as adsorption, chlorination oxidation, and advanced oxidation processes, often suffer from secondary pollution, incomplete treatment, or excessive energy consumption. Therefore, developing green and efficient degradation technologies is of great importance.
[0004] Photocatalysis, with its environmental friendliness, high efficiency, and broad-spectrum applicability, has become an ideal choice for degrading endocrine disruptors (EDCs). This technology utilizes reactive oxygen species generated by semiconductor materials under light to completely decompose EDCs into harmless substances, reducing the formation of toxic intermediates. Photocatalysis is not only simple to operate and cost-effective, but it can also operate continuously, reducing the accumulation and biomagnification of pollutants in the environment, protecting ecosystems and human health. Furthermore, photocatalysis can adapt to different environmental conditions and its energy source is renewable, making it a sustainable environmental purification method.
[0005] While photocatalytic degradation of endocrine disruptors is a highly efficient and environmentally friendly technology, it also has some limitations. For example, single-component photocatalysts such as TiO2, g-C3N4, and ZnO generally suffer from limitations such as limited light absorption range, severe recombination of photogenerated electron-hole pairs, and insufficient photocatalytic stability, resulting in limited degradation efficiency of BPA under visible light conditions. In recent years, although many methods have been proposed to improve the catalytic activity of photocatalysts, their catalytic efficiency remains low. Therefore, exploring a simple and effective preparation method is crucial for the widespread application of photocatalytically efficient degradation of bisphenol A.
[0006] In existing technologies, CdS-based photocatalysts exhibit excellent visible light response due to their narrow band gap (~2.4 eV) and are widely used for the degradation of organic pollutants. However, CdS alone suffers from severe photocorrosion and poor cycle stability. ZnCdS solid solutions have been proposed as an improvement, as they improve the band gap structure to some extent and combine the stability of ZnS with the visible light response characteristics of CdS. However, ZnCdS still inevitably suffers from rapid recombination of photogenerated carriers and low quantum efficiency, thus limiting its degradation efficiency.
[0007] On the other hand, Bi-based oxyhalides have gradually attracted attention in recent years due to their unique layered structure and tunable band structure. 12 O 17 Cl2 is a typical narrow-bandgap oxyhalide with strong visible light absorption and good chemical stability. Previous studies have shown that Bi... 12 O 17 Cl2 exhibits some degradation activity for organic pollutants under visible light, but its overall catalytic efficiency is not high due to the still significant electron-hole recombination.
[0008] To this end, researchers have proposed constructing heterojunction photocatalysts to promote electron-hole separation and improve photocatalytic activity. Currently, several common types of heterojunctions include:
[0009] 1. ZnCdS / TiO2 heterojunction: The stability of TiO2 is used to improve the photocorrosion problem of ZnCdS. However, due to the wide band gap of TiO2 (~3.2eV), its utilization rate of visible light is low, and the efficiency improvement of the entire heterojunction under visible light driving is limited.
[0010] 2. ZnCdS / CdS heterojunction: Charge transfer is achieved through a stepped band structure, improving the efficiency of partial charge separation. However, this "combination of similar sulfides" still fails to fundamentally solve the problems of CdS photocorrosion and poor cycling stability.
[0011] 3. BiOX (X = Cl, Br, I) / CdS heterojunction: BiOX-based materials possess advantages such as layered structure and visible light response, enabling them to form heterojunctions with CdS and improve charge separation efficiency. However, photocorrosion of CdS remains an unavoidable problem. More importantly, most BiOX materials have limited absorption capacity in the visible light region, thus limiting the extent to which the degradation rate can be improved.
[0012] 4. ZnCdS / g-C3N4 heterojunction: g-C3N4, as a free metal catalyst, exhibits good stability and visible light response, but its electron mobility is low and recombination rate is high. Although combining it with ZnCdS provides some improvement, the overall photocatalytic efficiency remains limited.
[0013] 5. Bi-based oxyhalide (e.g., BiOCl, BiOBr) / sulfide heterojunctions: Bi-based materials have a layered structure and a built-in electric field, which can promote carrier separation. However, the relatively wide band gap or undesirable energy level positions of materials such as BiOCl and BiOBr limit the visible light absorption range and reactivity after binding with sulfides.
[0014] Therefore, developing a visible light photocatalytic material that is simple to prepare, has higher visible light utilization, higher bisphenol A degradation rate, better stability, and is reusable will be a key research goal in this field. Summary of the Invention
[0015] The purpose of this invention is to provide a Bi 12 O 17 A method for preparing Cl2 / ZnCdS heterojunction photocatalysts is proposed to address the problem of limited degradation efficiency of CdS-based photocatalysts.
[0016] Another object of the present invention is to provide a Bi 12 O 17 The Cl2 / ZnCdS heterojunction photocatalyst aims to construct a photocatalytic material with efficient visible light response, excellent charge separation capability, and good stability.
[0017] The third objective of this invention is to provide a Bi 12 O 17 The application of Cl2 / ZnCdS heterojunction photocatalysts in the degradation of organic pollutants has enabled the efficient degradation of organic pollutants such as bisphenol A.
[0018] The technical solution of this invention is: (one)
[0020] A kind of Bi 12 O 17 The preparation method of Cl2 / ZnCdS heterojunction photocatalyst includes the following steps:
[0021] A. Preparation of Bi 12 O 17 Cl2 precursor: A certain amount of Bi(NO3)3·5H2O, KCl, and NH4Cl were weighed and dissolved in ethylene glycol solution, and dispersed by ultrasonic vibration; the pH of the system was adjusted to 8-10 using NaOH solution, and stirring was continued to obtain a homogeneous mixed solution; the mixed solution was subjected to a hydrothermal reaction; after the reaction was completed, it was cooled to room temperature, and the product was collected by centrifugation, washed alternately with deionized water and anhydrous ethanol, dried, and calcined in air to obtain Bi. 12 O 17 Cl2 precursor;
[0022] B. Preparation of Bi 12 O 17 Cl2 / ZnCdS: The Bi obtained in step A 12 O 17 The Cl2 precursor was ultrasonically dispersed in deionized water to form a homogeneous suspension; under stirring conditions, zinc acetate dihydrate, cadmium acetate dihydrate, and Na2S·9H2O solution were added sequentially to react with Bi. 12 O 17 Cl2 was brought into full contact; NaOH solution was slowly added dropwise to adjust the pH to 9-11, and stirring was continued for 30-60 minutes; the resulting mixed solution was subjected to a hydrothermal reaction; after the reaction was completed, the mixture was cooled to room temperature, and the product was washed repeatedly with deionized water and methanol, and then dried under vacuum at 40-80 degrees Celsius to obtain Bi. 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst.
[0023] As a further improvement of the present invention, in step A, the molar ratio of Bi(NO3)3·5H2O, KCl, and ammonium chloride is 4.5-6:0.5-1:0-0.5.
[0024] As a further improvement of the present invention, in step A, the hydrothermal reaction is maintained at 120-150°C for 12-18 hours.
[0025] As a further improvement of the present invention, in step A, the calcination temperature is 400-600 degrees Celsius, the calcination time is 2-4 hours, and the heating rate is 5-20 degrees Celsius / min.
[0026] As a further improvement of the present invention, in step B, Bi 12 O 17 The mass ratio of Cl2, zinc acetate dihydrate, cadmium acetate dihydrate, and Na2S·9H2O is 50-200:21.95:2.653-26.53:2.418-24.18.
[0027] As a further improvement of the present invention, in step B, the hydrothermal reaction is maintained at 160-200°C for 18-24 hours. (two)
[0029] A kind of Bi 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst, composed of the above-mentioned Bi 12 O 17 The Cl2 / ZnCdS heterojunction photocatalyst was prepared by a specific method. (three)
[0031] A kind of Bi 12 O 17 Application of Cl2 / ZnCdS heterojunction photocatalysts in the degradation of organic pollutants.
[0032] The beneficial effects of this invention are: this invention uses Bi 12 O 17 Cl2 and ZnCdS construct a heterojunction. On the one hand, Bi 12 O 17 The unique layered structure and excellent visible light response of Cl2 complement and match the band structure of ZnCdS, enabling efficient separation and migration of photogenerated carriers. This significantly reduces the recombination rate of electron-hole pairs, broadens the light absorption range, and improves visible light utilization efficiency. On the other hand, Bi... 12 O 17 The introduction of Cl2 effectively alleviates the photocorrosion problem of ZnCdS under visible light irradiation, enhancing the overall stability and recyclability of the material. Simultaneously, this heterojunction synergistically promotes the generation of various reactive oxygen species during the reaction process, significantly improving the degradation rate and mineralization efficiency of bisphenol A. More importantly, the materials used in this invention are simple, the preparation method is convenient, and it is environmentally friendly, introducing no additional toxic components, thus possessing good sustainability and practical application potential. Therefore, this invention not only overcomes the problems of insufficient photoresponse, severe photocorrosion, and carrier recombination existing in existing ZnCdS, BiOX / CdS, and ZnCdS / g-C3N4 heterojunction systems, but also exhibits unique advantages in terms of stability and degradation efficiency. Attached Figure Description
[0033] Figure 1 Bi prepared in Example 1 12 O 17 SEM images of Cl2 / ZnCdS;
[0034] Figure 2 Bi prepared in Example 1 and Comparative Examples 1 and 2 12 O 17 Cl2 / ZnCdS, Bi12 O 17 FT-IR spectra of Cl2 and ZnCdS;
[0035] Figure 3 Bi prepared in Example 1 and Comparative Examples 1 and 2 12 O 17 Cl2 / ZnCdS, Bi 12 O 17 UV diffuse reflectance spectra of Cl2 and ZnCdS;
[0036] Figure 4 Bi prepared in Example 1 and Comparative Examples 1 and 2 12 O 17 Cl2 / ZnCdS, Bi 12 O 17 Comparison of the performance of visible light photocatalytic degradation of bisphenol A by Cl2 and ZnCdS;
[0037] Figure 5 Bi prepared in Example 1 12 O 17 Cyclic experimental diagram of visible light catalytic degradation of bisphenol A by Cl2 / ZnCdS. Detailed Implementation
[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0039] Example 1
[0040] A kind of Bi 12 O 17 The preparation method of Cl2 / ZnCdS heterojunction photocatalyst includes the following steps:
[0041] A. Preparation of Bi 12 O 17 Cl2 precursor: Weigh 4.5 mmol Bi(NO3)3·5H2O, 0.75 mmol KCl, and 0.25 mmol NH4Cl and dissolve them in 40 mL ethylene glycol. Sonicate the solution for 1 hour to ensure complete dispersion. Adjust the pH to 9.0 with NaOH and continue stirring for 2 hours to obtain a homogeneous mixture. Transfer the mixture to a 100 mL PTFE-lined autoclave and hydrothermally react at 140 °C for 15 hours. After the reaction, cool to room temperature, collect the product by centrifugation, wash alternately with deionized water and anhydrous ethanol, dry, and calcine at 500 °C for 3 hours at a heating rate of 10 °C / min to obtain Bi. 12 O 16 Cl2 precursor.
[0042] B. Preparation of Bi 12 O 17Cl2 / ZnCdS: 150mg Bi 12 O 17 The Cl2 precursor was ultrasonically dispersed in 50 mL of deionized water to form a homogeneous suspension. Under stirring, 21.95 mg of zinc acetate dihydrate, 13.33 mg of cadmium acetate dihydrate, and 12.01 mg of Na2S·9H2O were added. After thorough stirring, NaOH solution was slowly added dropwise to adjust the pH to 10, and stirring continued for 40 minutes. The mixture was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 20 hours. After the reaction, the mixture was cooled to room temperature, and the product was repeatedly washed with deionized water and methanol, then vacuum dried at 40 °C to obtain Bi. 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst.
[0043] Figure 1 The Bi prepared in this embodiment 12 O 17 SEM images of Cl2 / ZnCdS. Figure 1 Showing the shape and size of the material, Bi 12 O 17 The Cl2 / ZnCdS heterojunction photocatalyst exhibits a non-uniform stacked nanosheet structure after successful composite formation.
[0044] Comparative Example 1
[0045] Only Bi photocatalyst was prepared 12 O 16 Cl2: Weigh 4.5 mmol Bi(NO3)3·5H2O, 0.375 mmol KCl, and 0.375 mmol NH4Cl and dissolve them in 40 mL ethylene glycol. Sonicate the solution for 1 hour to ensure complete dispersion. Adjust the pH of the solution to 9.0 with NaOH and continue stirring for 2 hours to obtain a homogeneous mixture. Transfer the mixture to a 100 mL PTFE-lined autoclave and hydrothermally react at 140 °C for 15 hours. After the reaction, cool to room temperature, collect the product by centrifugation, wash alternately with deionized water and anhydrous ethanol, dry, and calcine at 500 °C for 3 hours at a heating rate of 10 °C / min to obtain the catalyst Bi. 12 O 16 Cl2.
[0046] Comparative Example 2
[0047] Preparation of ZnCdS catalyst material only: 21.95 mg zinc acetate dihydrate, 13.33 mg cadmium acetate dihydrate, and 12.01 mg Na₂S·9H₂O were ultrasonically dispersed in 50 mL deionized water to form a homogeneous suspension. After thorough stirring, NaOH solution was slowly added dropwise to adjust the pH to 10, and stirring was continued for 40 minutes. The mixture was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and reacted at 180 °C for 20 hours. After the reaction was completed, the mixture was cooled to room temperature, and the product was repeatedly washed with deionized water and methanol, and then dried under vacuum at 60 °C to obtain the ZnCdS catalyst material.
[0048] Figure 2 Bi prepared in Example 1 and Comparative Examples 1 and 2 12 O 17 Cl2 / ZnCdS, Bi 12 O 17 FT-IR spectra of Cl2 and ZnCdS. At 482 cm⁻¹ -1 846cm -1 and 1347cm -1 The series of peaks observed nearby are attributed to Bi. 12 O 17 Stretching vibrations of Bi-O bonds, Bi-Cl bonds, and O-Bi-O units in Cl2. For ZnCdS, 1498 cm⁻¹ -1 The nearby vibrational peaks correspond to Cd-S bonds. The stretching vibrations of Zn-S typically fall in the low wavenumber region of the far infrared and have weak IR activity. Conventional FT-IR measurements (400-4000 cm⁻¹) -1 The sensitivity to this region is insufficient. Furthermore, in Bi... 12 O 17 Bi was also observed in Cl2 / ZnCdS 12 O 17 The characteristic peaks of both Cl2 and ZnCdS materials further demonstrate the successful composite composition of the materials.
[0049] Figure 3 Bi prepared in Example 1 and Comparative Examples 1 and 2 12 O 17 Cl2 / ZnCdS, Bi 12 O 17 The UV diffuse reflectance spectra of Cl2 and ZnCdS. It can be observed that single Bi... 12 O 17 The light absorption cutoff edge of Cl2 is approximately 512 nm. In contrast, ZnCdS absorbs light across the entire visible wavelength range, with a cutoff edge of approximately 548 nm, theoretically compensating for the limitations of Bi. 12 O 17The shortcomings of Cl2 materials can be seen after their successful composite. 12 O 17 The Cl2 / ZnCdS material exhibits light absorption performance covering almost the entire visible light spectrum from 300 to 800 nm, with a light absorption cutoff edge of approximately 531 nm, and retains a certain absorption tail peak.
[0050] Example 2
[0051] A kind of Bi 12 O 17 The preparation method of Cl2 / ZnCdS heterojunction photocatalyst includes the following steps:
[0052] A. Preparation of Bi 12 O 17 Cl2 precursor: Weigh 6 mmol Bi(NO3)3·5H2O, 0.5 mmol KCl, and 0.5 mmol NH4Cl and dissolve them in 35 mL ethylene glycol. Sonicate the solution for 1 hour to ensure complete dispersion. Adjust the pH to 10.0 with NaOH and continue stirring for 1.5 hours to obtain a homogeneous mixture. Transfer the mixture to a 100 mL PTFE-lined autoclave and hydrothermally react at 120 °C for 18 hours. After the reaction, cool to room temperature, collect the product by centrifugation, wash alternately with deionized water and anhydrous ethanol, dry, and calcine at 400 °C for 4 hours at a heating rate of 20 °C / min to obtain Bi. 12 O 16 Cl2 precursor.
[0053] B. Preparation of Bi 12 O 17 Cl2 / ZnCdS: 50mg Bi 12 O 17 The Cl2 precursor was ultrasonically dispersed in 45 mL of deionized water to form a homogeneous suspension. Under stirring, 21.95 mg of zinc acetate dihydrate, 2.653 mg of cadmium acetate dihydrate, and 2.418 mg of Na2S·9H2O were added. After thorough stirring, NaOH solution was slowly added dropwise to adjust the pH to 9, and stirring continued for 50 minutes. The mixture was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 160 °C for 24 hours. After the reaction, the mixture was cooled to room temperature, and the product was repeatedly washed with deionized water and methanol, then dried under vacuum at 80 °C to obtain Bi. 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst.
[0054] Example 3
[0055] A kind of Bi 12 O 17The preparation method of Cl2 / ZnCdS heterojunction photocatalyst includes the following steps:
[0056] A. Preparation of Bi 12 O 17 Cl2 precursor: Weigh 6 mmol Bi(NO3)3·5H2O and 1.0 mmol KCl and dissolve them in 40 mL ethylene glycol. Sonicate the solution for 1 hour to ensure complete dispersion. Adjust the pH to 8 with NaOH and continue stirring for 2 hours to obtain a homogeneous mixture. Transfer the mixture to a 100 mL PTFE-lined autoclave and hydrothermally react at 150 °C for 12 hours. After the reaction, cool to room temperature, collect the product by centrifugation, wash alternately with deionized water and anhydrous ethanol, dry, and calcine at 600 °C for 2 hours at a heating rate of 5 °C / min to obtain Bi. 12 O 16 Cl2 precursor.
[0057] B. Preparation of Bi 12 O 17 Cl2 / ZnCdS: 200mg Bi 12 O 17 The Cl2 precursor was ultrasonically dispersed in 50 mL of deionized water to form a homogeneous suspension. 21.95 mg of zinc acetate dihydrate, 26.53 mg of cadmium acetate dihydrate, and 24.18 mg of Na2S·9H2O were added. After thorough stirring, NaOH solution was slowly added dropwise to adjust the pH to 11, and stirring continued for 30 minutes. The mixture was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 200 °C for 18 hours. After the reaction, the mixture was cooled to room temperature, and the product was repeatedly washed with deionized water and methanol, then dried under vacuum at 60 °C to obtain Bi. 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst.
[0058] (I) Evaluation of photocatalytic activity:
[0059] Bi photocatalysts prepared in Example 1 and Comparative Examples 1 and 2 12 O 17 Cl2 / ZnCdS, Bi 12 O 16 Bisphenol A degradation experiments were conducted using Cl2 and ZnCdS, respectively, as follows:
[0060] The photodegradation process was carried out in a 250 mL custom-made double-walled quartz beaker equipped with a cooling water circulation system to maintain a constant reaction temperature. A 300 W xenon lamp (λ > 420 nm) was used as the visible light source, with an average luminous intensity of 100 mW / cm². 2Before the reaction began, 10 mg of photocatalyst was dispersed in a 10 mg / L bisphenol A solution, and the pH was controlled at approximately 7 using 0.1 M hydrochloric acid or sodium hydroxide solution. The suspension was continuously stirred throughout the reaction. A dark adsorption experiment was conducted 30 minutes before light exposure to achieve adsorption-desorption equilibrium between bisphenol A and the photocatalyst. During photodegradation, 1 mL of the reaction solution was taken at regular intervals and passed through a 0.22 μm filter for ultra-high performance liquid chromatography (UHPLC) analysis. The mobile phase was acetonitrile and ultrapure water (50:50 v / v), and the detection wavelength was 278 nm. The degradation efficiency was calculated using relative concentration (C / CO).
[0061] Figure 4 Bi prepared in Example 1 and Comparative Examples 1 and 2 12 O 17 Cl2 / ZnCdS, Bi 12 O 17 A comparison of the performance of Cl2 and ZnCdS in the visible light catalytic degradation of bisphenol A. (See figure) Figure 4 As shown, the 1-hour degradation rate of bisphenol A by ZnCdS alone is 10%, while that by Bi alone is... 12 O 17 The degradation rate of bisphenol A by Cl2 within 1 hour was less than 60%, indicating that Bi2O3 alone could not achieve this. 12 O 17 Cl2 lacks significant photocatalytic activity, while single ZnCdS, even with appropriate energy level positions, exhibits limited photocatalytic activity due to rapid in-situ carrier recombination, and slow free radical generation leads to slow bisphenol A degradation. Ultimately, the constructed Bi... 12 O 17 The degradation rate of bisphenol A in the Cl2 / ZnCdS heterojunction composite material was successfully increased to 98% after 1 hour, and the degradation rate reached 90% after 30 minutes of reaction.
[0062] (II) Cyclic Experiment:
[0063] Bi prepared in Example 1 12 O 17 After the first reaction of Cl2 / ZnCdS was completed, the solution containing the photocatalyst was centrifuged, and the lower layer of material was dried at 60°C for 8 hours. Then, it was put back into the reactor for the next photoreaction. Except for the material, the other reaction conditions were kept the same as the first time. After the second reaction was completed, the above steps were repeated, and a total of five bisphenol A degradation experiments were carried out.
[0064] Figure 5 Bi prepared in Example 1 12 O 17 A cyclic experimental diagram of visible light photocatalytic degradation of bisphenol A using Cl2 / ZnCdS. (See diagram below.) Figure 5As shown, the degradation yield of bisphenol A was above 95% in five consecutive experiments, indicating that Bi... 12 O 17 The photocatalytic degradation activity of Cl2 / ZnCdS remained good after five cycles, indicating that the material has excellent stability.
[0065] The results of the two experiments above show that: with a xenon lamp as the light source and a light intensity of 100 mW / cm², 2 Under visible light (λ>400nm) irradiation, with a catalyst dosage of 10 mg, a reaction solution of 10 mg / L bisphenol A, an initial temperature of room temperature, and a pH of 7, Bi 12 O 17 The Cl2 / ZnCdS photocatalytic material achieved a 98% degradation rate of bisphenol A after 60 minutes, and could degrade 90% of bisphenol A in 30 minutes without the addition of a co-catalyst. This degradation rate significantly exceeds that of similar photocatalysts. Furthermore, the material exhibits stable photocatalytic performance after multiple reactions, demonstrating its practical application value.
[0066] This invention uses Bi 12 O 17 The construction of a tight heterojunction between Cl2 and ZnCdS enables effective separation of photogenerated electrons and holes, thereby significantly improving the efficiency of visible light catalysis.
[0067] The preparation method of this invention achieves high crystallinity, uniform distribution, and high reproducibility of the material by controlling the reaction temperature, time, precursor ratio, and pH conditions. This invention clarifies the components Bi(NO3)3·5H2O, KCl, NH4Cl, and Zn. 2+ Cd 2+ and S 2- The optimal performance can be obtained by precisely controlling the molar ratio range and reaction conditions.
Claims
1. A Bi 12 O 17 The method for preparing Cl2 / ZnCdS heterojunction photocatalyst is characterized by: Includes the following steps: A. Preparation of Bi 12 O 17 Cl2 precursor: Weigh out Bi(NO3)3·5H2O, KCl and NH4Cl and dissolve them in ethylene glycol solution; The pH of the system was adjusted to 8-10 using NaOH solution, and stirring was continued to obtain a homogeneous mixed solution. The mixed solution was then subjected to a hydrothermal reaction. After the reaction was completed, the solution was cooled to room temperature, the product was collected, washed, dried, and then calcined in air to obtain Bi. 12 O 17 Cl2 precursor; B. Preparation of Bi 12 O 17 Cl2 / ZnCdS: The Bi obtained in step A 12 O 17 The Cl2 precursor was dispersed in deionized water to form a homogeneous suspension; under stirring conditions, zinc acetate dihydrate, cadmium acetate dihydrate, and Na2S·9H2O solution were added sequentially to react with Bi. 12 O 17 Cl2 was brought into full contact; NaOH solution was added dropwise to adjust the pH to 9-11, and stirring was continued; the resulting mixed solution was subjected to a hydrothermal reaction; after the reaction was completed, the mixture was cooled to room temperature, and the product was dried to obtain Bi. 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst.
2. A Bi according to claim 1 12 O 17 The method for preparing Cl2 / ZnCdS heterojunction photocatalyst is characterized by: In step A, the molar ratio of Bi(NO3)3·5H2O, KCl, and ammonium chloride is 4.5-6:0.5-1:0-0.5, and the number of moles of ammonium chloride is not 0.
3. A Bi according to claim 1 12 O 17 The method for preparing Cl2 / ZnCdS heterojunction photocatalyst is characterized by: In step A, the hydrothermal reaction is maintained at 120-150℃ for 12-18 hours.
4. A Bi according to claim 1 12 O 17 The method for preparing Cl2 / ZnCdS heterojunction photocatalyst is characterized by: In step A, the calcination temperature is 400-600 degrees Celsius, the calcination time is 2-4 hours, and the heating rate is 5-20 degrees Celsius / min.
5. A Bi according to claim 1 12 O 17 The method for preparing Cl2 / ZnCdS heterojunction photocatalyst is characterized by: In step B, Bi 12 O 17 The mass ratio of Cl2, zinc acetate dihydrate, cadmium acetate dihydrate, and Na2S·9H2O is 50-200:21.95:2.653-26.53:2.418-24.
18.
6. A Bi according to claim 1 12 O 17 The method for preparing Cl2 / ZnCdS heterojunction photocatalyst is characterized by: In step B, the hydrothermal reaction is maintained at 160-200℃ for 18-24 hours.
7. A Bi 12 O 17 Cl2 / ZnCdS heterojunction photocatalyst, characterized in that: A Bi according to any one of claims 1-6 12 O 17 The Cl2 / ZnCdS heterojunction photocatalyst was prepared by a specific method.
8. A Bi according to claim 7 12 O 17 Application of Cl2 / ZnCdS heterojunction photocatalyst in the degradation of organic pollutants.