阅读说明：本技术 一种C/ZnO/BiOI三元复合光催化材料 (C/ZnO/BiOI ternary composite photocatalytic material ) 是由 谭冲 李俊生 刘蕊 夏至 左金龙 于 2021-01-30 设计创作，主要内容包括：本发明公开了一种C/ZnO/BiOI三元复合光催化材料。该材料制备采用如下步骤：1)称取一定量的乙酸锌于30mL蒸馏水中,加入一定量的葡萄糖,搅拌10min,加入一定量的聚乙二醇,用特定浓度的NaOH调节pH,搅拌30min后进行水热反应。冷却后,用去离子水和乙醇洗涤,经离心、烘干后,在一定温度的马弗炉里煅烧一定时间,得到ZnO/C光催化材料。2)取一定量Bi(NO-3)-3·5H-2O和KI于20ml乙醇中,剧烈搅拌下缓慢加入20ml蒸馏水,持续搅拌一定时间后减压过滤,使用蒸馏水洗涤沉淀并在特定温度下烘干,得到BiOI光催化材料。3)取一定量的C/ZnO、BiOI分别溶于20ml去离子水中,剧烈搅拌一定时间,将C/ZnO溶液滴加到BiOI中,超声一定时间,离心后在一定温度烘干,得到C/ZnO/BiOI光催化材料。本发明采用的合成方法流程简单,操作简便,无二次污染。合成的光催化材料具有形貌均一、性能优异等特点。本发明工作属于光催化材料领域。(The invention discloses a C/ZnO/BiOI ternary composite photocatalytic material. The preparation method of the material comprises the following steps: 1) weighing a certain amount of zinc acetate in 30mL of distilled water, adding a certain amount of glucose, stirring for 10min, adding a certain amount of polyethylene glycol, adjusting the pH value by using NaOH with a specific concentration, stirring for 30min, and then carrying out hydrothermal reaction. And after cooling, washing with deionized water and ethanol, centrifuging, drying, and calcining in a muffle furnace at a certain temperature for a certain time to obtain the ZnO/C photocatalytic material. 2) Taking a certain amount of Bi (NO) 3 ) 3 ·5H 2 O and KI in 20ml ethanol, slowly added with vigorous stirringAnd (3) continuously stirring 20ml of distilled water for a certain time, then carrying out reduced pressure filtration, washing the precipitate with distilled water, and drying at a specific temperature to obtain the BiOI photocatalytic material. 3) Respectively dissolving a certain amount of C/ZnO and a certain amount of BiOI in 20ml of deionized water, violently stirring for a certain time, dropwise adding the C/ZnO solution into the BiOI, ultrasonically treating for a certain time, centrifuging, and drying at a certain temperature to obtain the C/ZnO/BiOI photocatalytic material. The synthetic method adopted by the invention has the advantages of simple process, simple and convenient operation and no secondary pollution. The synthesized photocatalytic material has the characteristics of uniform appearance, excellent performance and the like. The invention belongs to the field of photocatalytic materials.)

1. A C/ZnO/BiOI ternary composite photocatalytic material is characterized in that the preparation of the C/ZnO/BiOI ternary composite photocatalytic material with the nanometer size is carried out according to the following steps:

firstly, according to the mass ratio of Zn element, glucose, alkali source and surfactant being 1: 0.93-1.17: 2-2.67: 0.042-0.083, preparing Zn source and alkali source solution with specific concentration, and adding specific amount of glucose and surfactant into the Zn source solution to obtain C/ZnO precursor solution;

and secondly, dropwise adding the alkali source solution into the C/ZnO precursor solution at a dropping rate of 1-3 seconds per drop, transferring the mixed solution to a high-pressure reaction kettle for hydrothermal reaction, wherein the mixed solution accounts for about 70% of the volume of the reaction kettle, and maintaining the hydrothermal temperature of 140-180 ℃ for 2-5 hours. After washing, alcohol washing and drying, the hydrothermal reaction product is moved into a muffle furnace, calcined for 1-3 hours at the temperature of 200-400 ℃ in the air atmosphere, and cooled to room temperature to obtain the nano-sized C/ZnO photocatalytic material;

weighing Bi source and I source with specific mass in ethylene glycol with specific amount according to the ratio of Bi element to I element being 1: 1; slowly dripping a specific amount of distilled water under the condition of vigorous stirring at the rotating speed of 2000-5000 r/min, continuously stirring for 1-2 h, then carrying out reduced pressure filtration, and drying to obtain the BiOI photocatalytic material;

and fourthly, weighing C/ZnO and BiOI with specific mass according to the composite ratio of the C/ZnO to the BiOI of 1: 0.15-0.35, dispersing the C/ZnO and the BiOI in distilled water, stirring vigorously for 40min, dropwise adding the BiOI solution into the C/ZnO solution at the dropping rate of 1-3 seconds per drop, and carrying out ultrasonic treatment for 2-4 h. And centrifuging and drying to finally obtain the C/ZnO/BiOI ternary composite photocatalytic material.

2. The C/ZnO/BiOI ternary composite photocatalytic material of claim 1, wherein in the first step, the Zn element concentration is 0.0545mol/L, the glucose concentration is 0.0509-0.0609 mol/L, the alkali source concentration is 0.1091-0.1455 mol/L, and the surfactant concentration is 0.0023-0.0045 mol/L.

3. The C/ZnO/BiOI ternary composite photocatalytic material of claim 1, wherein the Zn source in the first step is zinc sulfate, zinc acetate dihydrate, zinc nitrate hexahydrate or zinc sulfate heptahydrate compound.

4. The C/ZnO/BiOI ternary composite photocatalytic material of claim 1, wherein the surfactant in step one is cetyl trimethyl ammonium bromide, polyethylene glycol, polyvinylpyrrolidone.

Technical Field

The invention relates to a C/ZnO/BiOI ternary composite photocatalytic material.

Background

ZnO is a II-VI cluster semiconductor oxide, has a forbidden band width of 3.37eV at room temperature, belongs to a direct band gap semiconductor material, and has good electrical, mechanical and optical properties. ZnO is widely used in photocatalytic oxidation technology, and is receiving attention due to its low cost, biocompatibility and chemical stability. However, the forbidden band of ZnO is wide, the photocatalytic oxidation reaction can only be excited by ultraviolet light, the utilization rate of sunlight is only 4%, and ZnO as a photocatalytic material has the problems of high recombination rate of electron-hole pairs, inability to absorb the visible light part of the solar spectrum, slow degradation at the interface of semiconductor liquid and the like, so that the application of ZnO is limited, and a series of attempts are made to solve the defects of ZnO.

Research shows that compounding C in ZnO can expand the absorption spectrum range of ZnO photocatalyst. However, in the preparation process of the C/ZnO catalyst, the C source may react with ZnO, or the excessive C source covers the surface of zinc oxide to prevent the ZnO from reacting with a degradation target, so that the photocatalytic performance is not good enough. And single BiOI photoproduction electron holes are easy to recombine, and the photocatalysis efficiency is influenced. In view of the advantages and the disadvantages of the catalysts, the C/ZnO and the BiOI are compounded to form the compound catalyst C/ZnO/BiOI, and the formation of the heterojunction after the compounding greatly improves the utilization rate of the catalyst to light, can generate electron transfer among components, delays the compounding of electron-hole pairs and improves the speed and the efficiency of degrading organic matters by photocatalysis. Today, the environmental situation is severe, the research and development of efficient composite photocatalysts are urgent, and the photocatalyst has both theoretical significance and practical value.

Zhoushai et al 2017 in the patent of C/ZnO lithium ion battery cathode material with a persimmon cake-shaped core-shell structure and a preparation method thereof, anhydrous ethanol, zinc acetate dihydrate, ethanolamine, glucose and the like are used as raw materials, and the time and the temperature of hydrothermal reaction are controlled, so that the C/ZnO material with the persimmon cake-shaped core-shell structure can be prepared, and a large amount of time is consumed in the preparation process. Carrying out hydrothermal reaction for 2-6 h at 150-180 ℃; calcining for 2-6 h at 600-800 ℃ and calcining for 2-6 h at 400-600 ℃ to finally obtain the C/ZnO lithium ion battery cathode material. The method has the problems of complex operation, complex flow, long preparation period and the like.

In the article 'preparation of C/ZnO composite material based on camellia oleifera shells and application of C/ZnO composite material in lead-carbon batteries', Liangqiu et al in 2020 adopts a sol-gel method to prepare the camellia oleifera shells C/ZnO composite material, and in the preparation process of the material, the drying is carried out for 6 hours in a forced air drying oven, and N is carried out₂The temperature is kept for 2h at 600 ℃ in the atmosphere, the preparation period is long, and impurities are easily introduced by a sol-gel method, so that the prepared powder is impure.

2016 Liujunli et al in the patent of a preparation method of snowflake ZnO/BiOI composite material, a microwave-assisted hydrothermal method is adopted to prepare a flower ZnO nanorod, and sodium dodecyl sulfate is used in the preparation process. Sodium lauryl sulfate is known to be toxic, irritating to mucous membranes, the eyelids and the skin of the respiratory tract and to cause allergic reactions in the respiratory system. The safety of this preparation method is to be investigated.

Yuanxin et al in 2018 patent "preparation method and application of ZnO/BiOI heterojunction photocatalyst" adopts precipitation-deposition method to compound ZnO and BiOI to prepare ZnO/BiOI heterojunction photocatalyst, and the method is not easy to control the position of precipitation and has the defects of poor repeatability, larger generated particles and low uniformity.

In 2019, Wanglinshan et al, in a patent of a preparation method of ZnO-BiOI composite microspheres suitable for industrial production, prepare ZnO-BiOI composite microspheres with an average diameter of 2-8 μm and uneven particle size, need to magnetically stir for 5-8h in the preparation process, and dry for 8-12 h at 70-80 ℃, although the method is suitable for industrial production, the problems of complicated preparation process and high time consumption still exist.

In 2019, Wanglinshan et al, in the process of preparing ZnO in a patent of preparation method of microspherical ZnO-BiOI composite material, introduce impurity phosphorus and remove the impurity phosphorus by a precipitation method, so that certain energy waste is caused. In addition, stirring and boiling reflux are required for 5-8h in the sample preparation process, stirring and reaction are required in a reaction kettle for 2-5h, the method is too long in time consumption, and a large amount of time is required in the preparation process.

In the patent ' a preparation method of hollow ZnO ', Chua ' Pneumon et al in 2017 adopt a spray thermal decomposition method in a gas phase method to prepare a ZnO photocatalytic material. It is worth mentioning that the hollow ZnO material prepared by the method has serious fragmentation, uneven grain diameter and non-uniform appearance. This result would directly lead to an uncontrolled photocatalytic activity of the material.

2018, Yanchenjun et al, in the patent "a preparation method of micron/nano ZnO with controllable morphology under normal pressure and low temperature conditions", prepares micron/nano ZnO with various morphologies under normal pressure and low temperature conditions. It is worth noting that this preparation method uses oleylamine as a solvent, which is known to have an irritating odor and to burn and corrode the skin. The safety of this preparation method is to be investigated.

In a patent of nano rod-shaped BiOI photocatalyst and a preparation method thereof by Liuhong et al in 2018, the BiOI photocatalyst is prepared by the following method: first Bi (NO)₃)₃Completely dissolving in oleic acid, adding KI, stirring for 7-13 days, adding water, hydrolyzing to generate BiOI, and finally centrifuging, taking precipitate, washing and drying to obtain the nano-rod-shaped BiOI photocatalyst. The preparation method has a long period and has certain problems in the practical application process.

In the ' bismuth oxyiodide visible-light-induced photocatalyst ' and the preparation method and application thereof ' of the patent of Wangli in 2020, bismuth source, iodine source and ethylene glycol are used as raw materials, the bismuth oxyiodide visible-light-induced photocatalyst is prepared by adopting a solvothermal method, a solvothermal reaction system is positioned in a closed container, the reaction condition is not convenient to detect visually, only the result can be seen, and the reaction mechanism is difficult to research.

Although the above-mentioned methods have made outstanding contributions in the preparation of photocatalytic materials, there are a number of common problems with these preparation methods, such as: the preparation process is complicated, the requirements on raw materials are strict, and the catalytic performance of the obtained catalyst with special morphology is not strong. In comparison, the method has the advantages of simple process, convenient operation, easy control of parameters, cheap and easily obtained raw materials and higher catalytic activity of the catalyst.

In summary, the C/ZnO/BiOI material with excellent photocatalytic performance is synthesized by a simple hydrothermal method, and the C/ZnO/BiOI material meets the relevant requirements on the material in practical application.

Disclosure of Invention

The invention aims to solve the problems of high price of raw materials, complex and fussy process flow, long preparation time, unsuitable mass production of production efficiency, poor photocatalytic activity of a photocatalyst and the like of the existing preparation method of the C/ZnO/BiOI photocatalytic material, and provides a preparation method of a C/ZnO/BiOI ternary composite photocatalytic material.

The preparation method of the C/ZnO/BiOI ternary composite photocatalytic material comprises the following steps:

firstly, the ratio of the Zn element, glucose, alkali source and surfactant is 1 (0.93-1.17): (2-2.67): (0.042-0.083), preparing Zn source and alkali source solution with specific concentration, and adding specific amount of glucose and surfactant into the Zn source solution to obtain C/ZnO precursor solution.

And secondly, dropwise adding the alkali source solution into the C/ZnO precursor solution at a dropping rate of 1-3 seconds per drop, transferring the mixed solution to a high-pressure reaction kettle for hydrothermal reaction, wherein the mixed solution accounts for about 70% of the volume of the reaction kettle, and maintaining the hydrothermal temperature of 140-180 ℃ for 2-5 hours. And (3) washing, alcohol washing and drying the hydrothermal reaction product, transferring the product into a muffle furnace, calcining for 1-3 h at 200-400 ℃ in the air atmosphere, and cooling to room temperature to obtain the nano-sized C/ZnO photocatalytic material. The hydrothermal method is adopted, and the obtained particles are high in purity, small in particle size, good in crystal form and controllable. The preparation process has short time consumption, simple process and high benefit.

Weighing a Bi source with a specific mass and I source in specific amount of ethylene glycol according to the ratio of Bi element to I element of 1: 1; slowly dropping a specific amount of distilled water under the vigorous stirring at the rotating speed of 2000-5000 r/min, continuously stirring for 1-2 h, then carrying out reduced pressure filtration, and drying to obtain the BiOI photocatalytic material. The preparation process parameters are easy to control, and the preparation process is short in time consumption.

And fourthly, weighing C/ZnO and BiOI with specific mass according to the composite ratio of C/ZnO to BiOI of 1 (0.15-0.35), respectively dispersing the C/ZnO and BiOI in distilled water, violently stirring for 40min, dropwise adding the BiOI solution into the C/ZnO solution at the dropping rate of 1-3 s/drop, and carrying out ultrasonic treatment for 2-4 h. And centrifuging and drying to obtain the C/ZnO/BiOI ternary composite photocatalytic material. The method is simple and quick to operate and high in efficiency. The high-frequency ultrasonic wave can accelerate the formation of ZnO and BiOI heterojunction, and simultaneously, the sample dispersibility is better.

1. The concentrations of the Zn element, the glucose, the alkali source and the surfactant in the step one are 0.0545mol/L, (0.0509-0.0609) mol/L, (0.1091-0.1455) mol/L and (0.0023-0.0045) mol/L respectively.

2. The Zn source in the first step is zinc sulfate (ZnSO)₄) Zinc acetate dihydrate (C)₄H₆O₄Zn·2H₂O), zinc nitrate hexahydrate (Zn (NO)₃)₂·6H₂O) or zinc sulfate heptahydrate (ZnSO)₄·7H₂O) compound.

3. The surfactant in the first step is Cetyl Trimethyl Ammonium Bromide (CTAB), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP).

The invention has the following beneficial effects:

the C/ZnO/BiOI photocatalyst is prepared by a simple hydrothermal method, so that the catalyst reaches a nanometer level, and the synthesized C/ZnO/BiOI ternary composite photocatalytic material has uniform chemical components; the invention adopts polyethylene glycol as a surfactant, can effectively control the morphology and particle size of the catalyst, and enables the synthesized C/ZnO/BiOI ternary composite photocatalytic material to have uniform morphology and uniform particle size; the C/ZnO/BiOI ternary composite photocatalytic material prepared by the method has extremely strong photocatalytic activity and meets the relevant requirements on materials in practical application.

The C/ZnO/BiOI ternary composite photocatalytic material disclosed by the invention can be used for photocatalytic decomposition of organic pollutants, and takes sunlight or ultraviolet light as a light source. During the photocatalytic reaction, a certain amount of catalyst (0.5-1 g/L) is added under the stirring condition, and the aqueous solution of organic pollutants such as rhodamine B, cefuroxime sodium and the like with a certain concentration (5-20 mg/L) is degraded within a certain time (0.5-3 h). For example: catalyzing and degrading 5mg/L rhodamine B solution, taking 100ml rhodamine B solution, adding a catalyst (0.5-1 g/L), carrying out catalytic reaction under sunlight or ultraviolet light, sampling 3-5 ml solution samples at intervals of 7.5-30 min, filtering, and measuring the absorbance of the solution by using an ultraviolet-visible spectrophotometer to detect the change of the solution concentration so as to calculate the degradation rate of organic pollutants.

The beneficial effects of the embodiment are as follows: the growth direction and the cluster mode of the catalyst crystal are controlled by polyethylene glycol in the C/ZnO/BiOI ternary composite photocatalytic material synthesized by the embodiment, and SEM results (figure 1) show that the composite photocatalytic material has a nanoscale size, a large specific surface area can provide more active sites, and the composite photocatalytic material has stronger catalytic activity. The results of a resolved Transmission Electron Microscope (TEM) (fig. 2) show that the presence of C in the sample can be observed and this coupling of C to ZnO will contribute to the charge carrier transfer process and thus improve the catalytic activity of ZnO. As can be seen from the figure, the ZnO, bio i lattice stripes are smooth and continuous, which indicates the highly crystalline nature of the ZnO, bio i material, where the ZnO and bio i interfaces exhibit cross-lattice stripes, which further confirms the formation of ZnO and bio i heterostructure nanocomposites. The XRD results (fig. 3) show the highly crystalline nature of the composite material prepared by the present invention, which is advantageous for the free electron transfer during the photocatalytic process of the photocatalyst. The high-efficiency transmission of free electrons can reduce the recombination probability of electron holes to a certain extent, so that the C/ZnO/BiOI composite photocatalytic material shows extremely excellent photocatalytic activity. The XPS result (figure 4) shows that the C/ZnO/BiOI ternary composite photocatalytic material is successfully prepared and does not contain other impurity elements. The shift in binding energy indicates a change in their chemical environment, further confirming the presence of a heterojunction between ZnO and the bio i. The FTIR result (figure 5) shows that the stretching vibration of C-O, Zn-O, Bi-O bond exists in the figure, and the three-component composite photocatalytic material is proved to be successfully prepared. The result of the UV-Vis DRS (figure 6) shows that the edge of an absorption band of the C/ZnO/BiOI ternary composite photocatalytic material is shifted to be near 465nm, and meanwhile, compared with pure ZnO, the band gap is reduced by 0.15nm, the response to visible light is greatly improved, and the photocatalytic activity of a sample is improved. The PL results (FIG. 7) show that the PL strength of the ternary composite photocatalytic material is significantly lower than that of pure ZnO and C/ZnO photocatalysts, which proves that the carrier charge in the ternary nanocomposite material has a relatively long life and is more likely to participate in the photocatalytic process, thereby obtaining better photocatalytic efficiency. The result of BET (figure 8) is that the C/ZnO/BiOI ternary composite photocatalytic material belongs to a mesoporous structure, has larger specific surface area, can provide more active sites, enables more electron holes to participate in the reaction, and greatly improves the photocatalytic efficiency.

In addition, the C/ZnO/BiOI ternary composite photocatalytic material synthesized by the embodiment has good photocatalytic performance, and Zhanghong et al in the paper research on modification of ZnO on BiOI-based photocatalyst and degradation of rhodamine B by degrading rhodamine B investigate ZnO/BiOI composite photocatalyst, and the degradation rate of rhodamine B in 120min under the optimal condition is 96.71%; zhang Jing et al in the thesis "preparation of ZnO-BiOI composite catalyst and its photocatalytic degradation benzidine performance research", when the visible light reaction is 40min, the degradation rate of benzidine reaches more than 90%; HAO FANG et al in a paper C @ ZnO Self-assembly Composite nanostructured with a Strong Absorption Capacity in UV-Visible Light and Its Optical Properties, prepared C @ ZnO material by an electrochemical deposition method, examined the photocatalytic activity by degrading methylene blue, the photocatalytic reaction reaches equilibrium after 240min, and the removal rate of the methylene blue is 92.33%; the degradation efficiency of the C/ZnO/BiOI ternary composite photocatalytic material on rhodamine B at 37.5min is 99.92%, and the degradation rate on methylene blue at 30min is 99.61%. Compared with the above examples, the light irradiation time is shortened, and the photocatalytic performance is improved, so that the C/ZnO/BiOI ternary composite photocatalytic material prepared by the research has more excellent photocatalytic performance.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) picture of a C/ZnO/BiOI ternary composite photocatalytic material

FIG. 2 is a Transmission Electron Microscope (TEM) photograph of the C/ZnO/BiOI ternary composite photocatalytic material

FIG. 3 is an X-ray diffraction (XRD) spectrogram of the C/ZnO/BiOI ternary composite photocatalytic material

FIG. 4 is an X-ray photoelectron spectroscopy (XPS) spectrum of the C/ZnO/BiOI ternary composite photocatalytic material

FIG. 5, Fourier infrared spectroscopy (FTIR) spectrum of C/ZnO/BiOI ternary composite photocatalytic material

FIG. 6 is a drawing showing an ultraviolet-visible diffuse reflection spectrum (UV-Vis DRS) spectrum of the C/ZnO/BiOI ternary composite photocatalytic material

FIG. 7 shows Photoluminescence (PL) spectra of C/ZnO/BiOI ternary composite photocatalytic material

FIG. 8 shows an adsorption-desorption isotherm (BET) spectrum of the C/ZnO/BiOI ternary composite photocatalytic material

FIG. 9 is a graph showing the relationship between the degradation efficiency of the C/ZnO/BiOI ternary composite photocatalytic material for rhodamine B and the photocatalytic time (first embodiment)

FIG. 10 is a graph showing the relationship between the degradation efficiency of the C/ZnO/BiOI ternary composite photocatalytic material for methylene blue and the photocatalytic time (second embodiment)

FIG. 11 is a graph showing the relationship between the degradation efficiency of the C/ZnO/BiOI ternary composite photocatalytic material for cefuroxime sodium and the photocatalytic time (detailed description of the third embodiment)

FIG. 12, C/ZnO/BiOI ternary composite photocatalytic material stability experiment

Detailed Description

The technical solution of the present invention is not limited to the following specific embodiments, but includes any combination of the specific embodiments.

The first embodiment is as follows: in the embodiment, the preparation method of the C/ZnO/BiOI ternary composite photocatalytic material is carried out according to the following steps:

firstly, 1.317g of zinc acetate is weighed and dissolved in 30ml of deionized water, 1g of glucose is added, and the mixture is stirred for 10 min. Adding 1g polyethylene glycol, stirring well, adding 0.2M NaOH (60ml) to adjust pH to 12, and stirring for 30 min. Transferring the mixture into a 150ml reaction kettle to react for 3h at 180 ℃, cooling the mixture to room temperature, washing the mixture with 100ml deionized water and 100ml ethanol, and centrifuging the mixture. Drying at 70 ℃. Calcining at 300 ℃ for 3 h. Obtaining the ZnO/C photocatalytic material.

Secondly, 20mL of ethylene glycol and 0.97gBi (NO) are added into a 100m L beaker in sequence₃)₃·5H₂O and 0.332g KI are stirred and dissolved to form a uniform solution; slowly dripping 20mL of distilled water under the condition of violent stirring, continuously stirring for 1h, and then filtering under reduced pressure; washing the precipitate with distilled water for 2-3 times, and drying at 60 ℃ to obtain the BiOI photocatalytic material.

Weighing 0.8g C/ZnO and dissolving in 20ml of deionized water, dissolving 0.27g of BiOI in 20ml of deionized water, violently stirring for 40min, dropwise adding the C/ZnO solution into the BiOI, and carrying out ultrasound treatment for 2 h. Drying at 70 ℃ after centrifugation. Obtaining the C/ZnO/BiOI photocatalytic material.

Degradation is carried out by 5 mg.L by using the prepared ZnO, C/ZnO and C/ZnO/BiOI photocatalytic materials^-1The degradation rate of the rhodamine B solution (figure 9) is ZnO, C/ZnO and C/ZnO/BiOI from small to large in sequence. After the degradation is carried out for 45min, the degradation efficiency of the C/ZnO/BiOI reaches 99.8 percent, is 11.4 percent higher than that of the C/ZnO and is 2.29 percent higher than that of pure ZnO. The result shows that the C/ZnO/BiOI ternary composite photocatalytic material has high-efficiency photocatalytic degradation capability on rhodamine B solution under simulated sunlight. Compared with a pure ZnO material, the improvement of the degradation effect of the C/ZnO/BiOI can be attributed to the fact that the addition of the C improves the conduction rate of electrons, and the heterojunction formed between the ZnO and the BiOI also greatly reduces the recombination probability of electron-hole pairs of the ZnO material, so that the photocatalysis efficiency is improved. In Rodamine B ZnO film photocatalytic degradation, a nano ZnO film is used as a catalyst to carry out a photocatalytic degradation test on rhodamine B. The result shows that the degradation rate of rhodamine B reaches 99.6 percent after ultraviolet irradiation for 60min by adopting the three-layer film ZnO as the catalyst and adopting the rhodamine B solution with the initial concentration of 5 mg/L. Compared with the C/ZnO/BiOI ternary composite photocatalytic material, the C/ZnO/BiOI ternary composite photocatalytic material degrades rhodamine B solution with the same concentrationThe solution is stirred for 45min under simulated sunlight, and the degradation rate can reach 99.8 percent (figure 9). The degradation time is greatly shortened, and the photocatalytic performance is obviously improved.

The second embodiment is as follows:

firstly, 1.317g of zinc acetate is weighed and dissolved in 30ml of deionized water, 1.025g of glucose is added, and stirring is carried out for 10 min. Adding 2g polyethylene glycol, stirring well, adding 0.2M NaOH (80ml) to adjust pH to 12, and stirring for 30 min. Transferring the mixture into a 150ml reaction kettle to react for 2.5h at 160 ℃, cooling the mixture to room temperature, washing the mixture with 100ml of deionized water and 100ml of ethanol, and centrifuging the mixture. Drying at 70 ℃. Calcining at 350 ℃ for 3.5 h. Obtaining the C/ZnO photocatalytic material.

Secondly, 20mL of ethylene glycol and 0.97gBi (NO) are added into a 100mL beaker in sequence₃)₃·5H₂O and 0.332g KI are stirred and dissolved to form a uniform solution; slowly dripping 20mL of distilled water under the condition of violent stirring, continuously stirring for 1h, and then filtering under reduced pressure; washing the precipitate with distilled water for 2-3 times, and drying at 60 ℃ to obtain the BiOI photocatalytic material.

Weighing 0.8g C/ZnO and dissolving in 20ml of deionized water, dissolving 0.27g of BiOI in 20ml of deionized water, violently stirring for 40min, dropwise adding the C/ZnO solution into the BiOI, and carrying out ultrasonic treatment for 1.5 h. Drying at 70 ℃ after centrifugation. Obtaining the C/ZnO/BiOI photocatalytic material.

Degrading 10 mg.L by using the prepared ZnO, C/ZnO and C/ZnO/BiOI photocatalytic materials^-1The degradation rate of the methylene blue solution (figure 10) is ZnO, C/ZnO and C/ZnO/BiOI from small to large. After 60min of degradation, the degradation efficiency of the C/ZnO/BiOI reaches 99.03 percent, which is 8.85 percent higher than that of the C/ZnO and 57.8 percent higher than that of pure ZnO. The result shows that the C/ZnO/BiOI ternary composite photocatalytic material has high-efficiency photocatalytic degradation capability on methylene blue solution under simulated sunlight. Compared with a pure ZnO material, the improvement of the degradation effect of the C/ZnO/BiOI can be attributed to the fact that the addition of the C improves the conduction rate of electrons, and the heterojunction formed between the ZnO and the BiOI also greatly reduces the recombination probability of electron-hole pairs of the ZnO material, so that the photocatalysis efficiency is improved.

The third concrete implementation mode:

firstly, 1.317g of zinc acetate is weighed and dissolved in 30ml of deionized water, 1.025g of glucose is added, and stirring is carried out for 10 min. Adding 1g polyethylene glycol, stirring well, adding 0.2M NaOH (80ml) to adjust pH to 12, and stirring for 30 min. Transferring the mixture into a 150ml reaction kettle to react for 2.5h at 170 ℃, cooling the mixture to room temperature, washing the mixture with 100ml of deionized water and 100ml of ethanol, and centrifuging the mixture. Drying at 70 ℃. Calcining at 250 ℃ for 3.5 h. Obtaining the C/ZnO photocatalytic material.

Secondly, 20mL of ethylene glycol and 0.97gBi (NO) are added into a 100mL beaker in sequence₃)₃·5H₂O and 0.332g KI are stirred and dissolved to form a uniform solution; slowly dripping 20mL of distilled water under the condition of violent stirring, continuously stirring for 1h, and then filtering under reduced pressure; washing the precipitate with distilled water for 2-3 times, and drying at 60 ℃ to obtain the BiOI photocatalytic material.

Weighing 0.8g C/ZnO and dissolving in 20ml of deionized water, dissolving 0.12g of BiOI in 20ml of deionized water, violently stirring for 40min, dropwise adding the C/ZnO solution into the BiOI, and carrying out ultrasonic treatment for 2.5 h. Drying at 70 ℃ after centrifugation. Obtaining the C/ZnO/BiOI photocatalytic material.

Prepared ZnO, C/ZnO and C/ZnO/BiOI photocatalytic materials are used for 0.1 g.L^-1Degradation is 20 mg.L^-1In the cefuroxime sodium solution (fig. 11), the three samples have similar adsorption effect on the cefuroxime sodium solution in the first 30min dark reaction, and the adsorption effect of the C/ZnO/BiOI ternary composite photocatalytic material on the cefuroxime sodium solution is higher than that of pure ZnO and C/ZnO. This indicates that the high specific surface area of the C/ZnO/BiOI composite catalyst has excellent adsorption effect on organic pollutants. After illumination, the C/ZnO/BiOI ternary composite photocatalytic material has the highest degradation efficiency on the cefuroxime sodium solution, and shows excellent photocatalytic performance. After 60min of illumination, the degradation efficiency of the ternary composite photocatalytic material on the cefuroxime sodium solution reaches 82.03%, which is 40.82% higher than that of the pure ZnO material on the cefuroxime sodium solution. This shows that, under the irradiation of ultraviolet light, the C/ZnO/BiOI ternary composite photocatalytic material has high-efficiency photocatalytic degradation capability on the cefuroxime sodium solution. Compared with a pure ZnO material, the degradation effect of the ZnO material can be improved due to the formation of a heterostructure between ZnO and BiOI, the electron transfer rate is improved, and the recombination probability of electron-hole pairs of the ZnO material is greatly reduced.

The fourth concrete implementation mode: in the embodiment, the preparation method of the C/ZnO/BiOI ternary composite photocatalytic material is carried out according to the following steps:

firstly, 1.317g of zinc acetate is weighed and dissolved in 30ml of deionized water, 1g of glucose is added, and the mixture is stirred for 10 min. Adding 1.5g polyethylene glycol, stirring well, adding 0.2M NaOH (60ml) to adjust pH to 12, and stirring for 30 min. Transferring the mixture into a 150ml reaction kettle to react for 3h at 170 ℃, cooling the mixture to room temperature, washing the mixture with 100ml deionized water and 100ml ethanol, and centrifuging the mixture. Drying at 70 ℃. Calcining at 300 ℃ for 3 h. Obtaining the ZnO/C photocatalytic material.

Secondly, 20mL of ethylene glycol and 0.97gBi (NO) are added into a 100mL beaker in sequence₃)₃·5H₂O and 0.332g KI are stirred and dissolved to form a uniform solution; slowly dripping 20mL of distilled water under the condition of violent stirring, continuously stirring for 1h, and then filtering under reduced pressure; washing the precipitate with distilled water for 2-3 times, and drying at 60 ℃ to obtain the BiOI photocatalytic material.

Weighing 0.8g C/ZnO and dissolving in 20ml of deionized water, dissolving 0.27g of BiOI in 20ml of deionized water, violently stirring for 40min, dropwise adding the C/ZnO solution into the BiOI, and carrying out ultrasound treatment for 2 h. Drying at 70 ℃ after centrifugation. Obtaining the C/ZnO/BiOI photocatalytic material.

The prepared C/ZnO/BiOI photocatalytic material is circularly degraded by 5 mg.L under simulated sunlight^-1After each cycle of photocatalytic reaction, all the catalysts were collected, centrifuged and washed with distilled water and absolute ethanol for the next cycle of experiment (fig. 12). As can be seen from the figure, after 5 cycles of degrading rhodamine B, the degradation efficiency is slightly reduced from the original 99.5% to 99.2%, which can be attributed to the loss of the photocatalyst caused by scouring in the degradation process. The cycle test shows that the C/ZnO/BiOI photocatalyst has better long-term stability.