Au-Ag / g-C3N5 / Ag2V4O11 composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of composite photocatalytic materials, in particular to an Au-Ag / g-C3N5 / Ag2V4O11 composite material as well as a preparation method and application thereof. According to the specific technical scheme, the preparation method comprises the following steps: firstly, obtaining a nanosheet Au-Ag / g-C3N5 material in one step by using an in-situ reduction and roasting method; meanwhile, rod-shaped Ag2V4O11 is prepared by a hydrothermal method; and finally, the mixture of the Au-Ag / g-C3N5 and the Ag2V4O11 is stirred and roasted, and the Au-Ag / g-C3N5 / Ag2V4O11 composite material is obtained. The preparation method has the characteristics of simplicity in operation, low cost, environment friendliness, no need of complicated post-treatment steps and the like. Meanwhile, the composite material disclosed by the invention has relatively high photocatalytic activity, has relatively high photocatalytic degradation efficiency on bisphenol A and bisphenol S, and can be used for treating endocrine disrupter pollution in wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of composite photocatalytic materials, and particularly relates to an Au-Ag / g-C3N5 / Ag2V4O 11 composite material and its preparation method and application. Background Art

[0002] In recent years, with the rapid development of industry, various chemical products have flooded into human life, and more and more new organic pollutants have been detected in the water environment, posing a serious threat to the ecological environment. Among them, bisphenol endocrine disruptors, especially bisphenol A and bisphenol S, as a kind of low-toxic compounds, are widely used in the production of products such as resins, antioxidants, coatings, and rubbers. Due to a series of characteristics such as lipophilicity, carcinogenicity, and bioaccumulation, even trace amounts in water will cause great harm to human health. Therefore, there is an urgent need to develop green and efficient technical means to timely and effectively treat the wastewater containing these endocrine disruptors.

[0003] As a new type of water treatment technology, semiconductor photocatalytic technology can effectively remove various endocrine disruptors in the water environment, thus having broad application prospects. Among common photocatalysts, carbon nitride such as g-C3N4, as an organic semiconductor non-metallic material that can respond to visible light, has wide application value in the field of degrading environmental pollutants due to its good chemical stability, relatively narrow band gap (about 2.7 eV), and simple preparation method. In recent years, studies have shown that by adjusting the carbon-nitrogen ratio, g-C3N5 can be synthesized, making its photocatalytic performance better. However, like single-component g-C3N4, it still has problems such as low solar energy utilization rate and too fast recombination rate of photo-generated carriers, resulting in low photocatalytic efficiency. To solve this problem, using noble metals Au and Ag as co-catalysts to improve the catalyst performance is considered an effective method. Studies have shown that the recombination rate of photo-generated carriers of carbon nitride modified with Au or Ag noble metal nanoparticles will be significantly reduced (Colloids and Surfaces A: Physicochemical and Engineering Aspects 696 (2024) 134320; Chemosphere 344 (2023) 140325; Chinese Patent Publication No.: CN112570027A). However, when dealing with low-concentration and highly toxic bisphenol endocrine disruptors in wastewater, the degradation efficiency of such zero-dimensional / two-dimensional photocatalytic materials still needs to be improved. Ag2V4O 11Belonging to transitional group-V oxides, due to their suitable energy band structure, they have a relatively narrow band gap (1.8 - 2.08 eV), resulting in a strong electron transfer rate and good visible light absorption performance (Journal of Solid State Electrochemistry 26(2022)1951 - 1960; Chinese Patent Publication No.: CN105230659A). Coupled with the environmentally friendly characteristics, it has great application prospects in the field of visible light catalysis and has attracted great attention. For example, the invention patent with Chinese Patent Publication No. CN113731410A synthesized an Ag2V4O 11 / g-C3N4 composite photocatalyst, and the highest degradation rate of reactive blue 19 can reach 100% within 60 min. The enhanced photocatalytic activity is attributed to Ag2V4O 11 modifying g-C3N4 to form a heterojunction structure, which can promote the separation and migration of photo-generated carriers and shorten the band gap of g-C3N4. However, it is necessary to adjust the pH value of the reaction solution to 2.2 - 2.6 with HNO3, and the experimental conditions are harsh. Zhou et al. (Nanomaterials 10(2020)828) used the hydrothermal method to synthesize a TiO2 / Ag2V4O 11 nano-heterojunction photocatalytic material, and the degradation rate of rhodamine B under visible light irradiation is about 100% within 90 min. The enhanced photocatalytic activity benefits from the heterojunction formed by TiO2 and Ag2V4O 11 which expands the visible light absorption region, improves the generation rate and lifetime of photo-carriers. Therefore, combining it with other semiconductor photocatalytic materials to form a heterojunction structure can further reduce the recombination rate of photo-generated carriers, thereby improving the photocatalytic degradation efficiency of low-concentration and highly toxic bisphenol endocrine disruptors.

[0004] However, so far, there has been no report on in-situ loading of Au and Ag noble metal particles on g-C3N5, and then combining with Ag2V4O 11 to form a heterojunction to construct a composite material, preparation method and application related to Au-Ag / g-C3N5 / Ag2V4O 11 Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, by jointly using two means of noble metal cocatalysis and constructing heterojunctions, a Au-Ag / g-C3N5 / Ag2V4O 11 composite material, its preparation method and application are provided. The process of this material is relatively simple, the preparation cost is low, and the synthesis method has strong repeatability. The prepared Au-Ag / g-C3N5 / Ag2V4O 11 ​The heterojunction composite material has strong stability, can effectively inhibit the recombination of photo-generated carriers, thus significantly improving the photocatalytic activity, and overcoming the defect of poor photocatalytic performance of single semiconductors.

[0006] To achieve the above object, the present invention is realized through the following technical solutions:

[0007] The present invention discloses a Au-Ag / g-C3N5 / Ag2V4O 11 composite material, using g-C3N5 with in-situ deposited Au-Ag particles as the matrix to obtain Au-Ag / g-C3N5, and then 11 composite with Ag2V4O 11 to obtain the Au-Ag / g-C3N5 / Ag2V4O

[0008] corresponding, a preparation method of the Au-Ag / g-C3N5 / Ag2V4O 11 composite material as described in claim 1, comprising the following steps:

[0009] (1) Dissolve 3-amino-1,2,4-triazole and bromide in deionized water, add HAuCl4·4H2O solution and AgNO3, stir for 0.3 - 0.6 h, then dropwise add NaBH4 solution under ice-water bath conditions, continue to stir for 1 - 1.8 h, heat to dryness at 70 - 90 °C, then perform roasting, naturally cool to room temperature, wash, dry, and grind to obtain Au-Ag / g-C3N5 nanosheets;

[0010] (2) Disperse the Au-Ag / g-C3N5 prepared in step (1) and Ag2V4O 11 in absolute ethanol, stir vigorously until the absolute ethanol evaporates completely and stops, dry at 70 - 90 °C for 7 - 9 h, then grind and roast to obtain the Au-Ag / g-C3N5 / Ag2V4O 11 composite material.

[0011] Preferably, in step (1), the mass ratio of the 3-amino-1,2,4-triazole, bromide to deionized water is 1:6.5 - 7.5:200, the addition amounts of the HAuCl4·4H2O solution and AgNO3 are both 2% - 8% of the mass of the 3-amino-1,2,4-triazole, and the addition amount of the NaBH4 solution is 26% - 30% of the mass of the 3-amino-1,2,4-triazole.

[0012] Preferably, the bromide is sodium bromide, ammonium bromide or potassium bromide.

[0013] Preferably, in step (1), the concentration of the HAuCl4·4H2O solution is 5 - 10 g / L, and the concentration of the NaBH4 solution is 0.5 - 1.0 g / L.

[0014] Preferably, in step (1), the stirring speed is 100 - 200 rpm; during the calcination process, the heating rate is 4 - 8 °C / min, the holding time is 1 - 3 h, and the calcination temperature is 500 - 580 °C.

[0015] Preferably, in step (2), the mass ratio of the Au - Ag / g - C3N5 nanosheets to Ag2V4O 11 is 1:0.5 - 2, and the mass ratio of the total mass of the Au - Ag / g - C3N5 nanosheets and Ag2V4O 11 to absolute ethanol is 1:60 - 90.

[0016] Preferably, in step (2), the speed of vigorous stirring is 350 - 450 rpm; during the calcination process, the heating rate is 4 - 8 °C / min, the holding time is 1 - 3 h, and the calcination temperature is 500 - 580 °C.

[0017] Correspondingly, the application of an Au - Ag / g - C3N5 / Ag2V4O 11 composite material prepared by the preparation method as a photocatalytic material in treating wastewater containing endocrine disruptors.

[0018] Preferably, the concentration of endocrine disruptors in the wastewater is 10 mg / L, and the concentration of the Au - Ag / g - C3N5 / Ag2V4O 11 composite material in the wastewater is 0.4 mg / L.

[0019] The present invention has the following beneficial effects:

[0020] 1. The present invention obtains the nanosheet Au - Ag / g - C3N5 material in one step by in - situ reduction and calcination method, and obtains the Au - Ag / g - C3N5 / Ag2V4O 11 composite material by stirring and calcining the mixture of Au - Ag / g - C3N5 and rod - shaped Ag2V4O 11 The preparation method has the characteristics of simple operation, low cost, environmental friendliness, and no need for complex post - treatment steps. At the same time, the composite material of the present invention has high photocatalytic activity, and has high photocatalytic degradation efficiency for both bisphenol A and bisphenol S, and can be used for the treatment of endocrine disruptor pollution in wastewater.

[0021] 2. The Au - Ag / g - C3N5 / Ag2V4O 11The composite material has strong stability, a high repeatability of the synthesis method, and an easy-to-control preparation process. The Au-Ag / g-C3N5 is synthesized in situ by a one-step method, and the preparation process is simple. At the same time, the surface of g-C3N5 is modified with two noble metal nanoparticles, Au and Ag, which can effectively enhance the visible light absorption and reduce the recombination of photogenerated carriers, thereby improving the photocatalytic efficiency.

[0022] 3. Due to the differences in the energy band structures and energy level positions between g-C3N5 and Ag2V4O 11 The formed heterojunction interface significantly reduces the recombination efficiency of photogenerated carriers after the combination. Coupled with the synergistic effect of noble metal Au and Ag cocatalysts, when it is applied to the photocatalytic oxidation for removing endocrine disruptors in wastewater, it can improve the photocatalytic activity and overcome the defect of poor photocatalytic performance of single semiconductors. Brief Description of the Drawings

[0023] Figure 1 It is the X-ray diffraction (XRD) pattern of each material in each example and comparative example;

[0024] Figure 2 It is the scanning electron microscopy (SEM) photograph of each material in each example and comparative example;

[0025] Figure 3 It is the transmission electron microscopy (TEM) photograph of the composite material prepared in Example 2;

[0026] Figure 4 It is the SEM-EDS elemental analysis diagram of the composite material prepared in Example 2;

[0027] Figure 5 It is the photocatalytic degradation effect diagram of each material in each example and comparative example for endocrine disruptors (bisphenol A, bisphenol S);

[0028] Figure 6 It is the effect verification diagram of the photocatalytic stability (five-cycle experiment) of the composite material prepared in Example 2. Detailed Embodiments

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Unless otherwise specified, the technical means used in the implementation examples are conventional means well-known to those skilled in the art.

[0031] The present invention discloses an Au-Ag / g-C3N5 / Ag2V4O 11 composite material, with g-C3N5 in-situ deposited with Au-Ag particles as the matrix to obtain Au-Ag / g-C3N5, and then 11 combined with Ag2V4O 11 to obtain the Au-Ag / g-C3N5 / Ag2V4O

[0032] composite material. 11 The present invention also discloses a preparation method of the Au-Ag / g-C3N5 / Ag2V4O

[0033] (1) One-step preparation of Au-Ag / g-C3N5 by in-situ reduction and calcination: Dissolve 3-amino-1,2,4-triazole and bromide in deionized water, add HAuCl4·4H2O solution and AgNO3, stir for 0.3 - 0.6 h, then dropwise add NaBH4 solution under ice-water bath conditions for reduction reaction, continue to stir for 1 - 1.8 h, heat to dryness at 70 - 90 °C, spread the obtained sample on a magnetic boat, place it in a muffle furnace for calcination, take it out and let it cool naturally to room temperature after calcination to obtain a dark brown sample, centrifuge and wash it with deionized water 2 - 4 times, dry it at 70 - 90 °C for 7 - 9 h, and grind it to obtain Au-Ag / g-C3N5 nanosheets;

[0034] Among them, the mass ratio of the 3-amino-1,2,4-triazole, bromide to deionized water is 1:6.5 - 7.5:200, the addition amounts of the HAuCl4·4H2O solution and AgNO3 are both 2% - 8% of the mass of the 3-amino-1,2,4-triazole, and the addition amount of the NaBH4 solution is 26% - 30% of the mass of the 3-amino-1,2,4-triazole. The bromide is sodium bromide, ammonium bromide or potassium bromide. The concentration of the HAuCl4·4H2O solution is 5 - 10 g / L, and the concentration of the NaBH4 solution is 0.5 - 1.0 g / L.

[0035] Furthermore, the stirring speed is 100 - 200 rpm; during the calcination process, the heating rate is 4 - 8 °C / min, the holding time is 1 - 3 h, and the calcination temperature is 500 - 580 °C.

[0036] (2) Rod-shaped Ag2V4O 11Hydrothermal preparation: Weigh NH4VO3 and dissolve it in deionized water. Add a certain amount of AgNO3 under vigorous stirring until a light yellow suspension appears, then stop stirring. After aging at room temperature for 6 - 8 h, a precursor is obtained. Then transfer the obtained precursor into a high-pressure reactor, seal it well, put it into an oven, and react at 150 - 180 °C for 24 - 28 h. After the obtained product is naturally cooled to room temperature, wash it 2 - 4 times by centrifugation with deionized water, dry it at 70 - 90 °C for 7 - 9 h, and grind it into a powder to obtain rod-shaped Ag2V4O 11 ;

[0037] Among them, the mass ratio of NH4VO3, AgNO3 and deionized water is 1:0.5 - 0.9:100; the stirring speed is 350 - 450 rpm.

[0038] (3) Disperse the Au - Ag / g - C3N5 prepared in step (1) and the Ag2V4O prepared in step (2) 11 in absolute ethanol, stir vigorously until the absolute ethanol has completely evaporated and stopped, dry it at 70 - 90 °C for 7 - 9 h and then grind it. After calcination, the Au - Ag / g - C3N5 / Ag2V4O 11 composite material is obtained.

[0039] Among them, the mass ratio of the Au - Ag / g - C3N5 nanosheets and Ag2V4O 11 is 1:0.5 - 2, and the mass ratio of the total mass of the Au - Ag / g - C3N5 nanosheets and Ag2V4O 11 to absolute ethanol is 1:60 - 90. The speed of the vigorous stirring is 350 - 450 rpm; during the calcination process, the heating rate is 4 - 8 °C / min, the holding time is 1 - 3 h, and the calcination temperature is 500 - 580 °C.

[0040] The present invention discloses the application of an Au - Ag / g - C3N5 / Ag2V4O 11 composite material as a photocatalytic material in treating wastewater containing endocrine disruptors. The concentration of endocrine disruptors in the wastewater is 10 mg / L, and the concentration of the Au - Ag / g - C3N5 / Ag2V4O 11 composite material in the wastewater is 0.4 mg / L.

[0041] The following further elaborates the present invention with specific examples.

[0042] Example 1

[0043] An Au - Ag / g - C3N5 / Ag2V4O 11 composite material, with g - C3N5 in which Au - Ag particles are in - situ deposited as the matrix, and then combined with Ag2V4O 11Composite. Among them, the mass fractions of Au and Ag in-situ deposited on g-C3N5 are both 2%, and the mass ratio of Au-Ag / g-C3N5 to Ag2V4O 11 is 1:0.5.

[0044] The above 2Au-Ag / g-C3N5 / Ag2V4O 11 composite material is synthesized according to the following steps:

[0045] (1) Preparation of 2Au-Ag / g-C3N5: Weigh 0.2 g of 3-amino-1,2,4-triazole and 1.3 g of sodium bromide and dissolve them in 40 mL of deionized water. Add 0.8 mL of 5 g / L HAuCl4·4H2O solution and 0.004 g of AgNO3. After stirring at 100 rpm for 0.6 h, add 104 mL of 0.5 g / L NaBH4 solution dropwise under ice-water bath conditions for reduction reaction. Then continue to stir at 100 rpm for 1.8 h, heat to dryness at 70 °C. The obtained sample is spread on a magnetic boat and placed in a muffle furnace for roasting. After roasting, take it out and cool naturally to room temperature to obtain a dark brown sample. Wash it twice by centrifugation with deionized water, dry it at 70 °C for 9 h, and grind it to obtain 2Au-Ag / g-C3N5 nanosheets. Among them, the heating rate of the muffle furnace is 4 °C / min, the holding time is 1 h, and the roasting temperature is 500 °C.

[0046] (2) Preparation of Ag2V4O 11 : Weigh 0.1 g of NH4VO3 and dissolve it in 10 mL of deionized water. Add 0.05 g of AgNO3 under vigorous stirring at 350 rpm until a light yellow suspension appears, then stop stirring. After aging at room temperature for 6 h, the precursor is obtained. Then transfer the obtained precursor into a high-pressure reaction kettle, seal it well, put it into an oven, and react at 150 °C for 28 h. After the obtained product cools naturally to room temperature, wash it twice by centrifugation with deionized water, dry it at 70 °C for 9 h, and grind it into a powder to obtain rod-shaped Ag2V4O 11 .

[0047] (3) Preparation of 2Au-Ag / g-C3N5 / Ag2V4O 11 : Weigh 0.2 g of Au-Ag / g-C3N5 and 0.1 g of Ag2V4O 11 and disperse them in 22.8 mL of absolute ethanol. Stir vigorously at 350 rpm until the absolute ethanol evaporates completely and stops. Dry it at 70 °C for 9 h and then grind it. Subsequently, place it in a muffle furnace for roasting to obtain 2Au-Ag / g-C3N5 / Ag2V4O 11 composite material. Among them, the heating rate of the muffle furnace is 4 °C / min, the holding time is 1 h, and the roasting temperature is 500 °C.

[0048] The 2Au-Ag / g-C3N5 / Ag2V4O prepared by the above method 11 The composite material was used for photocatalytic oxidation degradation of bisphenol A and bisphenol S for 60 min, and the removal rates were 81.8% and 80.5% respectively.

[0049] Example 2

[0050] A Au-Ag / g-C3N5 / Ag2V4O 11 composite material, with g-C3N5 in-situ deposited with Au-Ag particles as the matrix, and then compounded with Ag2V4O 11 Among them, the mass fractions of Au and Ag in-situ deposited on g-C3N5 are both 4%, and the mass ratio of Au-Ag / g-C3N5 to Ag2V4O 11 is 1:1.

[0051] The above 4Au-Ag / g-C3N5 / Ag2V4O 11 composite material was synthesized according to the following steps:

[0052] (1) Preparation of 4Au-Ag / g-C3N5: Weigh 0.2 g of 3-amino-1,2,4-triazole and 1.36 g of potassium bromide and dissolve them in 40 mL of deionized water. Add 1.14 mL of 6 g / L HAuCl4·4H2O solution and 0.008 g of AgNO3. After stirring at a speed of 150 rpm for 0.5 h, dropwise add 80 mL of 0.7 g / L NaBH4 solution under ice-water bath conditions for reduction reaction. Then continue to stir at a speed of 150 rpm for 1.5 h, heat to dryness at 80 °C. The obtained sample was spread on a magnetic boat and placed in a muffle furnace for roasting. After roasting, take it out and cool naturally to room temperature to obtain a dark brown sample. Centrifuge and wash it 3 times with deionized water, dry it at 80 °C for 8 h, and grind it to obtain 4Au-Ag / g-C3N5 nanosheets. Among them, the heating rate of the muffle furnace is 5 °C / min, the holding time is 2 h, and the roasting temperature is 550 °C.

[0053] (2) Preparation of Ag2V4O 11 : Weigh 0.2 g of NH4VO3 and dissolve it in 20 mL of deionized water. Add 0.12 g of AgNO3 under violent stirring at a speed of 380 rpm until a light yellow suspension appears and then stop stirring. After aging at room temperature for 7 h, the precursor is obtained. Then transfer the obtained precursor into a high-pressure reaction kettle, seal it well, put it into an oven, and react at 160 °C for 26 h. After the obtained product naturally cools to room temperature, centrifuge and wash it 3 times with deionized water, dry it at 80 °C for 8 h, and grind it into a powder to obtain rod-shaped Ag2V4O 11 .

[0054] (3) 4Au-Ag / g-C3N5 / Ag2V4O11 Preparation: Weigh 0.2 g of Au-Ag / g-C3N5 and 0.2 g of Ag2V4O 11 Disperse them in 35.5 mL of absolute ethanol, stir vigorously at a speed of 380 rpm until the absolute ethanol has completely evaporated and stopped, dry at 80 °C for 8 h and then grind, and then place them in a muffle furnace for roasting to obtain 4Au-Ag / g-C3N5 / Ag2V4O 11 Composite material. Among them, the heating rate of the muffle furnace is 5 °C / min, the holding time is 2 h, and the roasting temperature is 550 °C.

[0055] The 4Au-Ag / g-C3N5 / Ag2V4O prepared by the above method 11 Composite material was used for photocatalytic oxidation degradation of bisphenol A and bisphenol S for 60 min, and the removal rates were 92.9% and 91.8% respectively.

[0056] Example 3

[0057] An Au-Ag / g-C3N5 / Ag2V4O 11 Composite material, with g-C3N5 in-situ deposited with Au-Ag particles as the matrix, and then combined with Ag2V4O 11 Composite. Among them, the mass fractions of Au and Ag in-situ deposited on g-C3N5 are both 6%, and the mass ratio of Au-Ag / g-C3N5 to Ag2V4O 11 is 1:1.5.

[0058] The above 6Au-Ag / g-C3N5 / Ag2V4O 11 Composite material is synthesized according to the following steps:

[0059] (1) Preparation of 6Au-Ag / g-C3N5: Weigh 0.2 g of 3-amino-1,2,4-triazole and 1.44 g of ammonium bromide, dissolve them in 40 mL of deionized water, add 1.5 mL of 8 g / L HAuCl4·4H2O solution and 0.012 g of AgNO3, stir at a speed of 180 rpm for 0.4 h, then dropwise add 72.5 mL of 0.8 g / L NaBH4 solution under ice-water bath conditions for reduction reaction, and then continue to stir at a speed of 180 rpm for 1.2 h, heat to dryness at 90 °C, spread the obtained sample on a magnetic boat, place it in a muffle furnace for roasting, take it out and cool to room temperature naturally after roasting, obtain a dark brown sample, wash it 4 times by centrifugation with deionized water, dry it at 90 °C for 7 h, and grind it to obtain 6Au-Ag / g-C3N5 nanosheets. Among them, the heating rate of the muffle furnace is 6 °C / min, the holding time is 2 h, and the roasting temperature is 560 °C.

[0060] (2) Ag2V4O 11Preparation: Weigh 0.3 g of NH4VO3 and dissolve it in 30 mL of deionized water. Add 0.21 g of AgNO3 under vigorous stirring at a speed of 400 rpm until a light yellow suspension appears, then stop stirring. After aging at room temperature for 7 h, the precursor is obtained. Then transfer the obtained precursor into a high-pressure reaction kettle, seal it well, put it into an oven, and react at 170 °C for 25 h. After the obtained product is naturally cooled to room temperature, centrifuge and wash it 4 times with deionized water, dry it at 90 °C for 7 h, and grind it into a powder to obtain rod-shaped Ag2V4O 11 .

[0061] (3) 6Au-Ag / g-C3N5 / Ag2V4O 11 Preparation: Weigh 0.2 g of Au-Ag / g-C3N5 and 0.3 g of Ag2V4O 11 Disperse them in 50.7 mL of absolute ethanol, stir vigorously at a speed of 400 rpm until the absolute ethanol completely evaporates and stops. After drying at 90 °C for 7 h, grind them, and then place them in a muffle furnace for roasting to obtain 6Au-Ag / g-C3N5 / Ag2V4O 11 Composite material. Among them, the heating rate of the muffle furnace is 6 °C / min, the holding time is 2 h, and the roasting temperature is 560 °C.

[0062] The 6Au-Ag / g-C3N5 / Ag2V4O 11 composite material prepared by the above method is used for photocatalytic oxidation degradation of bisphenol A and bisphenol S for 60 min, and the removal rates are 90.1% and 88.8% respectively.

[0063] Example 4

[0064] An Au-Ag / g-C3N5 / Ag2V4O 11 composite material, with g-C3N5 in-situ deposited with Au-Ag particles as the matrix, and then combined with Ag2V4O 11 composite. Among them, the mass fractions of Au and Ag in-situ deposited on g-C3N5 are both 8%, and the mass ratio of Au-Ag / g-C3N5 to Ag2V4O 11 is 1:2.

[0065] The above 8Au-Ag / g-C3N5 / Ag2V4O 11 composite material is synthesized according to the following steps:

[0066] (1) Preparation of 8Au-Ag / g-C3N5: Weigh 0.2 g of 3-amino-1,2,4-triazole and 1.5 g of potassium bromide and dissolve them in 40 mL of deionized water. Add 1.6 mL of 10 g / L HAuCl4·4H2O solution and 0.016 g of AgNO3. After stirring at a speed of 200 rpm for 0.3 h, add 60 mL of 1 g / L NaBH4 solution dropwise under ice-water bath conditions for reduction reaction. Then continue to stir at a speed of 200 rpm for 1 h, heat to dryness at 80 °C. The obtained sample is spread on a magnetic boat and placed in a muffle furnace for roasting. After roasting, take it out and let it cool naturally to room temperature to obtain a dark brown sample. Wash it by centrifugation with deionized water 3 times, dry it at 80 °C for 9 h, and grind it to obtain 8Au-Ag / g-C3N5 nanosheets. Among them, the heating rate of the muffle furnace is 8 °C / min, the holding time is 3 h, and the roasting temperature is 580 °C.

[0067] (2) Preparation of Ag2V4O 11 : Weigh 0.4 g of NH4VO3 and dissolve it in 40 mL of deionized water. Add 0.36 g of AgNO3 under vigorous stirring at a speed of 450 rpm until a light yellow suspension appears and then stop stirring. After aging at room temperature for 8 h, the precursor is obtained. Then transfer the obtained precursor into a high-pressure reaction kettle, seal it well, put it into an oven, and react at 180 °C for 24 h. After the obtained product naturally cools to room temperature, wash it by centrifugation with deionized water 3 times, dry it at 80 °C for 9 h, and grind it into a powder to obtain rod-shaped Ag2V4O 11 .

[0068] (3) Preparation of 8Au-Ag / g-C3N5 / Ag2V4O 11 : Weigh 0.2 g of Au-Ag / g-C3N5 and 0.4 g of Ag2V4O 11 and disperse them in 68.4 mL of absolute ethanol. Stir vigorously at a speed of 450 rpm until the absolute ethanol evaporates completely and then stop. Dry it at 80 °C for 9 h and then grind it. Subsequently, place it in a muffle furnace for roasting to obtain 8Au-Ag / g-C3N5 / Ag2V4O 11 composite material. Among them, the heating rate of the muffle furnace is 8 °C / min, the holding time is 3 h, and the roasting temperature is 580 °C.

[0069] The 8Au-Ag / g-C3N5 / Ag2V4O 11 composite material prepared by the above method was used to carry out photocatalytic oxidation degradation of bisphenol A and bisphenol S for 60 min, and the removal rates were 85.8% and 83.6% respectively.

[0070] Comparative Example 1

[0071] Directly use g-C3N5 as the application material for comparison.

[0072] Comparative Example 2

[0073] Directly use Ag2V4O 11 as the application material for comparison.

[0074] Comparative Example 3

[0075] Directly use 4Au - Ag / g - C3N5 as the application material for comparison.

[0076] Characterization method:

[0077] The photocatalytic experiment was carried out in a photoreactor, which mainly consisted of four parts: The light source system included a 500W Xe lamp, a λ>420nm cut-off filter and a cooling accessory; the reactor (a quartz tube with a capacity of 50 mL); an electromagnetic stirrer. Before irradiation, 50 mL of an aqueous solution containing 20 mg of photocatalyst and 10 mg / L of bisphenol endocrine disruptor (bisphenol A or bisphenol S) was magnetically stirred in the dark for 1 h. During irradiation, about 3 mL of the suspension was taken out of the reactor every 10 min and centrifuged to separate the photocatalyst. A total organic carbon analyzer (Shimadzu TOC - L CPH, Japan) was used to measure the antibiotic content in the supernatant of the sampled samples. The antibiotic content measured at different irradiation times was converted into the removal rate of antibiotics, which could be defined by the following expression:

[0078] Removal rate of antibiotics = (C0 - C t ) / C0×100%

[0079] where C0 and C t were the contents of bisphenol endocrine disruptors measured at 0 min of irradiation (i.e., just after adsorption) and t min, respectively.

[0080] Characterization experiment:

[0081] Figure 1 Are the X-ray diffraction (XRD) patterns of the materials of Comparative Example 1, 2, 3 and Example 1, 2, 3, 4. It can be seen that characteristic peaks belonging to Au, Ag and g - C3N5 can be seen in the 4Au - Ag / g - C3N5 composite material curve. In the Au - Ag / g - C3N5 / Ag2V4O 11 composite materials with different Ag2V4O 11 contents, characteristic peaks belonging to Au, Ag, g - C3N5 and Ag2V4O 11 can also be seen. And with the increase of the contents of Au, Ag and Ag2V4O 11 , the characteristic peaks belonging to Au, Ag and Ag2V4O 11 are significantly enhanced, indicating that Au - Ag, g - C3N5 and Ag2V4O 11 formed a composite material.

[0082] Figure 2 Scanning electron microscope (SEM) photos of the materials of Comparative Examples 1, 2, 3 and Examples 1, 2, 3, 4. As can be seen from Figure 2a, g-C3N5 is a two-dimensional nanosheet. As can be seen from Figure 2b, 4Au-Ag / g-C3N5 is also a two-dimensional nanosheet, but there are obvious particles on its surface, which is caused by being modified by noble metal nanoparticles of Au and Ag, and also indirectly indicates that Au and Ag particles are successfully deposited in situ on the surface of g-C3N5. As can be seen from Figure 2c, the synthesized Ag2V4O 11 is rod-shaped; as can be seen from Figures 2d (Example 1), 2e (Example 2), 2f (Example 3), and 2g (Example 4), the Au-Ag / g-C3N5 / Ag2V4O 11 composite material is based on g-C3N5 with in-situ deposited Au-Ag particles, and Ag2V4O 11 is also coated on the surface of g-C3N5 to form a heterojunction, enabling them to exert their respective advantages and produce a synergistic effect, so that the prepared Au-Ag / g-C3N5 / Ag2V4O 11 composite material has more excellent photocatalytic performance.

[0083] Figure 3 Transmission electron microscope (TEM) photo of the composite material prepared in Example 2. To further verify whether the composite material of the present invention is successfully synthesized, the composite material prepared in Example 2 with the best photocatalytic performance was selected for TEM characterization. As can be clearly seen from Figure 2 , Au-Ag particles are deposited on the surface of g-C3N5, and rod-shaped Ag2V4O 11 is coated on the surface of g-C3N5, indicating that the composite material of the present invention is successfully synthesized.

[0084] Figure 4 SEM-EDS elemental analysis diagram of the composite material prepared in Example 2. As can be seen from Figure 2 , the composite material prepared in Example 2 contains elements of Au, Ag, C, N, V, and O, which further confirms that the composite material of the present invention is successfully synthesized.

[0085] Figure 5Photocatalytic degradation effect diagrams of endocrine disruptors (bisphenol A, bisphenol S) for the materials of Comparative Examples 1, 2, 3 and Examples 1, 2, 3, 4. The adsorption capacities of endocrine disruptors for all materials in each example and comparative example are weak. However, when Au-Ag particles are in-situ deposited on g-C3N5 to form Au-Ag / g-C3N5 materials, the ability to remove endocrine disruptors is significantly higher than that of g-C3N5. This is because the use of Au-Ag noble metal nanoparticles as co-catalysts to modify the surface of g-C3N5 can effectively enhance visible light absorption and promote the separation of photo-generated electron-hole pairs, thereby improving the photocatalytic performance. After Au-Ag / g-C3N5 is 11 combined with Ag2V4O 11 , the ability to remove endocrine disruptors is significantly higher than that of Au-Ag / g-C3N5. Among them, Example 2 (4Au-Ag / g-C3N5 / Ag2V4O 11 ) composite material performs photocatalytic oxidation degradation of bisphenol A and bisphenol S for 60 min, and the effect is the best, with the removal rates reaching as high as 92.9% and 91.8% respectively. This is because after g-C3N5 is combined with Ag2V4O 11 , a heterojunction interface is formed, which can quickly transfer photo-generated electrons and holes, greatly reducing the recombination probability of photo-generated electrons and holes, thereby improving the photocatalytic performance of the composite material.

[0086] Figure 6 Figure for verifying the photocatalytic stability (five-cycle experiment) of the composite material prepared in Example 2. As can be seen from Figure 6 it, after five-cycle experiments, the degradation effect of the photocatalytic material in Example 2 still maintains good stability. After the fifth cycle of use, compared with the first time, it only decreases by 5.2% (bisphenol A) and 6.3% (bisphenol S) respectively, still maintaining a high removal efficiency, indicating that the composite photocatalytic material prepared by the present invention has strong stability.

[0087] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A Au-Ag / g-C3N5 / Ag2V4O 11 composite material, characterized in that: Using g-C3N5 with in-situ deposited Au-Ag particles as the matrix to obtain Au-Ag / g-C3N5, and then compounding it with Ag2V4O 11 to obtain the Au-Ag / g-C3N5 / Ag2V4O 11 composite material.

2. The preparation method of the Au-Ag / g-C3N5 / Ag2V4O 11 composite material as described in claim 1, characterized in that: It includes the following steps: (1) Dissolve 3-amino-1,2,4-triazole and bromide in deionized water, add HAuCl4·4H2O solution and AgNO3, stir for 0.3 - 0.6 h, then dropwise add NaBH4 solution under ice-water bath conditions, continue to stir for 1 - 1.8 h, heat to dryness at 70 - 90 °C, then carry out roasting, naturally cool to room temperature, wash, dry and grind to obtain Au-Ag / g-C3N5 nanosheets; (2) Disperse the Au-Ag / g-C3N5 and Ag2V4O prepared in step (1) 11 in absolute ethanol, stir vigorously until the absolute ethanol completely evaporates and stops, dry at 70 - 90 °C for 7 - 9 h, then grind, and obtain the Au-Ag / g-C3N5 / Ag2V4O 11 composite material after calcination.

3. The preparation method according to claim 2, characterized in that: In step (1), the mass ratio of 3-amino-1,2,4-triazole, bromide to deionized water is 1:6.5 - 7.5:200, the addition amounts of HAuCl4·4H2O solution and AgNO3 are both 2% - 8% of the mass of 3-amino-1,2,4-triazole, and the addition amount of NaBH4 solution is 26% - 30% of the mass of 3-amino-1,2,4-triazole.

4. The preparation method according to claim 3, wherein: The bromide is sodium bromide, ammonium bromide or potassium bromide.

5. The preparation method according to claim 3, characterized in that: In step (1), the concentration of the HAuCl4·4H2O solution is 5 - 10 g / L, and the concentration of the NaBH4 solution is 0.5 - 1.0 g / L.

6. The preparation method according to claim 2, characterized in that: In step (1), the stirring speed is 100 - 200 rpm; during the roasting process, the heating rate is 4 - 8 °C / min, the holding time is 1 - 3 h, and the roasting temperature is 500 - 580 °C.

7. The preparation method according to claim 2, characterized in that: In step (2), the mass ratio of the Au-Ag / g-C3N5 nanosheets and Ag2V4O 11 is 1:0.5 to 2, and the mass ratio of the total mass of the Au-Ag / g-C3N5 nanosheets and Ag2V4O 11 to absolute ethanol is 1:60 to 90.

8. The preparation method according to claim 7, characterized in that: In step (2), the speed of vigorous stirring is 350 - 450 rpm; during the roasting process, the heating rate is 4 - 8 °C / min, the holding time is 1 - 3 h, and the roasting temperature is 500 - 580 °C.

9. Use of the Au-Ag / g-C3N5 / Ag2V4O composite material prepared by the preparation method according to any one of claims 1 to 8 as a photocatalytic material in treating wastewater containing endocrine disruptors. 11 ​ 10. The application according to claim 9, wherein: The concentration of endocrine disruptors in the wastewater is 10 mg / L, and the concentration of the Au-Ag / g-C3N5 / Ag2V4O 11 composite material in the wastewater is 0.4 mg / L.

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