CN108940332B - High-activity MoS2/g-C3N4/Bi24O31Cl10Preparation method of composite photocatalyst - Google Patents

Abstract

The invention belongs to the technical field of new materials, new energy utilization and environmental pollution treatment, and relates to high-activity MoS₂/g‑C₃N₄/Bi₂₄O₃₁Cl₁₀A preparation method of a composite photocatalyst. Bi is prepared by taking bismuth nitrate, ammonium chloride and citric acid as raw materials and adopting an improved solution combustion method₂₄O₃₁Cl₁₀(ii) a g-C is prepared from melamine and acetic acid by one-step thermal polymerization method₃N₄(ii) a Ammonium molybdate and thiourea are used as raw materials, dimethylformamide is used as a solvent, and a hydrothermal method is adopted to prepare MoS₂(ii) a Subjecting the Bi subjected to ultrasonic dispersion treatment₂₄O₃₁Cl₁₀And g-C₃N₄、MoS₂And (3) carrying out ultrasonic mixing reaction in a methanol solution, washing, centrifuging and drying to obtain the composite photocatalyst. The method is simple and easy to implement, low in cost and good in repeatability, and has wide application prospects in the fields of photolysis of water, photocatalytic oxidation of environmental pollutants and the like.

Description

High-activity MoS2/g-C3N4/Bi24O31Cl10Preparation method of composite photocatalyst

Technical Field

The invention belongs to the technical field of new materials, new energy utilization and environmental pollution treatment, and relates to high-activity MoS₂/g-C₃N₄/Bi₂₄O₃₁Cl₁₀A preparation method of a composite photocatalyst.

Background

With the increasing increase of the environmental pollution problem, the photocatalytic technology receives more and more attention in the aspects of hydrogen production by photolysis and organic pollutant degradation. Wherein, TiO₂Has the advantages of low cost, good photocatalytic stability, high photocatalytic efficiency and the like, and is a common material in the field of photocatalysis. But TiO 2₂The photocatalyst can only be excited by ultraviolet light due to the wide forbidden band width of about 3.1eV, and the ultraviolet light only accounts for about 5% of the solar spectrum, so that the photocatalyst has low utilization rate of sunlight and limits the application of the photocatalyst in the aspect of environmental management to a certain extent. Therefore, to make the most of the solar energy, the development and research of new catalysts that can be excited by visible light are the focus and focus of research.

The bismuth-based catalyst is a novel visible light catalyst which is most concerned at present, has become good in the aspect of controlling environmental pollution, and is increasingly popular with researchers at home and abroad. The most outstanding advantage of the method is that the forbidden band width is narrow, and the characteristic is favorable for photocatalytic degradation of organic pollutants in the environment under visible light. Wherein Bi₂₄O₃₁Cl₁₀As an oxygen-enriched bismuth-based catalyst, the bismuth-based catalyst has the following advantages: the forbidden band width is small, about 2.8eV, and the energy can be excited by visible light; the chemical and physical stability is good; has a unique crystal structure and high quantum efficiency, and is becoming a research hotspot in recent years. Such as Jin et al, by hydrothermal method to prepare Bi with thickness of 300nm and width of 1-3 μm₂₄O₃₁Cl₁₀Photocatalyst, Bi in comparison with BiOCl₂₄O₃₁Cl₁₀In the visible light (>420 nm) can better absorb visible light under the irradiation and can effectively activate molecular oxygen to generate O₂·^-Thereby enhancing Bi₂₄O₃₁Cl₁₀The photocatalytic activity of visible light. YIn and the like adopt a method of combining hydrothermal treatment and heat treatment to prepare Bi₂₄O₃₁Cl₁₀The nano-sheet is used for degrading tetracycline hydrochloride, and the degradation rate of the tetracycline hydrochloride reaches over 80 percent when the nano-sheet is illuminated for 150min under visible light. However, pure Bi₂₄O₃₁Cl₁₀The photo-electron holes are easy to recombine, the specific surface area is small, the photocatalytic activity is low, and the actual industrial application cannot be met, therefore, various measures are needed to improve the photocatalytic activity, for example, different semiconductor materials with matched energy band positions are recombined to form a heterojunction, and the recombination rate of electrons and holes in the materials can be reduced.

MoS₂The graphene-like hexagonal close-packed layered structure material can absorb photons with visible light frequency, has high edge potential of a conduction band and a valence band, can effectively enhance the absorption capacity of light when being compounded with other photocatalysts, and can play a role in rapidly transmitting electrons. And g-C₃N₄Is a polymer semiconductor with a structure similar to graphene, and C, N atoms are hybridized by sp2 to form highly delocalized piA conjugated system. g-C₃N₄The material has the advantages of wide source, low price, chemical stability and the like of polymer materials, has certain absorption to visible light, and has better photocatalytic performance. And MoS₂And g-C₃N₄Position of valence and conduction bands and Bi₂₄O₃₁Cl₁₀Can be well matched to form a heterojunction, on one hand, enhances Bi₂₄O₃₁Cl₁₀Can effectively reduce Bi₂₄O₃₁Cl₁₀Recombination rate of internal electrons and holes, and in Bi₂₄O₃₁Cl₁₀Thin layer MoS coated on particle surface₂And g-C₃N₄The nano-sheet increases the specific surface area of the catalyst, and increases the pre-adsorption amount of the catalyst surface in organic pollutants, thereby being beneficial to improving the efficiency of photocatalytic reaction.

In view of the foregoing, there is a need for providing a MoS₂/g-C₃N₄/Bi₂₄O₃₁Cl₁₀A preparation method of a heterojunction photocatalyst.

Disclosure of Invention

To solve the above problems, the present invention provides a high activity MoS₂/g-C₃N₄/Bi₂₄O₃₁Cl₁₀A preparation method of a composite photocatalyst.

The preparation method of the invention firstly uses bismuth nitrate, ammonium chloride and citric acid as raw materials and adopts an improved solution combustion method to prepare Bi₂₄O₃₁Cl₁₀Then ultrasonically dispersing in a methanol solution; secondly, melamine and acetic acid are used as raw materials, and a one-step thermal polymerization method is adopted to prepare g-C₃N₄Then ultrasonically dispersing in a methanol solution; ammonium molybdate and thiourea are used as raw materials, dimethylformamide is used as a solvent, and a hydrothermal method is adopted to prepare MoS₂And carrying out ultrasonic dispersion treatment in a methanol solution. Finally, the Bi subjected to ultrasonic dispersion treatment₂₄O₃₁Cl₁₀And g-C₃N₄、MoS₂Ultrasonically mixing the mixture in a methanol solution for full reaction, washing, centrifuging and drying to obtain the MoS₂/g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

The technical scheme of the invention is as follows:

high-activity MoS₂/g-C₃N₄/Bi₂₄O₃₁Cl₁₀The preparation method of the composite photocatalyst comprises the following steps:

(1) bi is prepared by taking bismuth nitrate, ammonium chloride and citric acid as raw materials and adopting an improved solution combustion method₂₄O₃₁Cl₁₀

Mixing bismuth nitrate pentahydrate and citric acid, and dissolving in dilute nitric acid to obtain a mixed solution of bismuth nitrate pentahydrate and dilute nitric acid of citric acid, wherein the molar ratio of bismuth nitrate pentahydrate to citric acid is 1: 2; dissolving ammonium chloride in distilled water until the ammonium chloride is completely dissolved to obtain an ammonium chloride solution; under the condition of stirring, adding an ammonium chloride solution into a mixed solution of bismuth nitrate pentahydrate and dilute nitric acid of citric acid, wherein the molar ratio of the bismuth nitrate pentahydrate to the ammonium chloride is 1: 1, uniformly mixing until the solution is in a clear state, and adjusting the pH value of the solution to 5-6 by using ammonia water; heating and stirring for 3-4 h at 60-80 ℃, and then calcining for 3h at 600 ℃ to obtain light yellow powder, namely pure Bi₂₄O₃₁Cl₁₀；

(2) g-C is prepared from melamine and acetic acid by one-step thermal polymerization method₃N₄

Uniformly mixing melamine and acetic acid according to a molar ratio of 10:1, calcining for 2 hours at 500 ℃ to obtain light yellow powder, namely pure g-C₃N₄；

(3) Ammonium molybdate and thiourea are used as raw materials, dimethylformamide is used as a solvent, and a hydrothermal method is adopted to prepare MoS₂

Preparing a mixed solution of ammonium molybdate tetrahydrate and dimethyl formamide of thiourea, wherein the concentration of the mixed solution is 4.8-5.0 g/L, and the mass ratio of the ammonium molybdate tetrahydrate to the thiourea is 1: 2; stirring until the mixed solution of ammonium molybdate tetrahydrate and dimethylformamide of thiourea is in a transparent state; reacting for 24 hours at 200 ℃ in a reaction kettle, and cooling to room temperature; washing with deionized water, centrifuging to obtain black solidDrying the colored solid at 60-100 ℃ for 12-24 h to obtain MoS₂；

(4) Bi prepared in the step (1)₂₄O₃₁Cl₁₀Adding the mixture into a methanol solution, and performing ultrasonic treatment to obtain Bi with the concentration of 40-50 g/L₂₄O₃₁Cl₁₀A mixed solution with methanol; g-C prepared in the step (2)₃N₄Is added to Bi₂₄O₃₁Cl₁₀In a mixed solution with methanol, wherein g-C₃N₄And Bi₂₄O₃₁Cl₁₀The mass ratio is 0.01-0.1; continuing ultrasonic treatment, centrifuging, washing and centrifuging again to obtain a solid substance; drying the solid matter at 60-80 deg.c for 24-48 hr, cooling and grinding to obtain 1-10% g-C₃N₄/ Bi₂₄O₃₁Cl₁₀A composite photocatalyst;

(5) 5% g-C prepared in step (4)₃N₄/Bi₂₄O₃₁Cl₁₀Adding the mixture into a methanol solution, and performing ultrasonic treatment to obtain 5% g-C with the concentration of 40-50 g/L₃N₄/Bi₂₄O₃₁Cl₁₀A mixed solution with methanol; the MoS prepared in the step (3) is used₂Adding to 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀In a mixed solution with methanol, wherein, MoS₂With 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀The mass ratio of (A) to (B) is 0.03-0.07; continuing ultrasonic treatment, centrifuging, washing and centrifuging again to obtain a solid substance; drying the solid substance at 60-80 ℃ for 24-48 h, cooling and grinding to obtain 3-7% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

The invention has the beneficial effects that: tested, 5% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀The catalytic degradation rate of rhodamine B can reach 99%, and the degradation rate of the composite catalyst to tetracycline can reach more than 90% in 50min, and the composite catalyst is relatively pure Bi₂₄O₃₁Cl₁₀、5％MoS₂/Bi₂₄O₃₁Cl₁₀、5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀The photocatalytic efficiency is remarkably improved. The method is simple and easy to implement, low in cost and good in repeatability, and has wide application prospects in the fields of photolysis of water, photocatalytic oxidation of environmental pollutants and the like.

Drawings

FIG. 1 shows Bi₂₄O₃₁Cl₁、MoS₂、g-C₃N₄、5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀、5％MoS₂/Bi₂₄O₃₁Cl₁₀、 5％MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀XRD pattern of photocatalyst;

FIG. 2(a) shows Bi₂₄O₃₁Cl₁₀SEM image of photocatalyst;

FIG. 2(b) is 5% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀SEM spectra of the photocatalyst;

figure 2(c) is an EDS spectrum;

FIG. 3 is a UV-Vis spectrum of a photocatalyst; wherein a represents Bi₂₄O₃₁Cl₁₀B represents 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀C represents 5% MoS₂/Bi₂₄O₃₁Cl₁₀D represents 5% MoS₂/5％g-C₃N₄/ Bi₂₄O₃₁Cl₁₀And e represents MoS₂UV-Vis spectra of the photocatalyst;

FIG. 4 shows Bi₂₄O₃₁Cl₁₀、5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀、5％MoS₂/Bi₂₄O₃₁Cl₁₀、5％MoS₂ /5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀PL spectrum of the photocatalyst;

FIG. 5 shows the degradation efficiency of a photocatalyst on rhodamine B under visible light irradiation(ii) a Wherein a represents Bi₂₄O₃₁Cl₁₀B represents 1% g-C₃N₄/Bi₂₄O₃₁Cl₁₀C represents 3% g-C₃N₄/Bi₂₄O₃₁Cl₁₀D represents 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀E represents 10% g-C₃N₄/Bi₂₄O₃₁Cl₁₀And f represents 5% MoS₂/Bi₂₄O₃₁Cl₁₀G represents 3% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀H represents 5% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀And i represents 7% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀；

Bi prepared in FIG. 6₂₄O₃₁Cl₁₀、5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀、5％MoS₂/Bi₂₄O₃₁Cl₁₀、 5％MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀The degradation efficiency of the photocatalyst to the tetracycline under the visible light illumination is improved.

Detailed Description

The following further describes a specific embodiment of the present invention with reference to the drawings and technical solutions.

The preparation method of the invention is used for preparing 3-7% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀Composite photocatalyst and preparation of 5% MoS₂/Bi₂₄O₃₁Cl₁₀The composite photocatalyst has the effect of comparing with the effects of various composite photocatalysts.

Examples 1

(1)Bi₂₄O₃₁Cl₁₀The preparation of (1): dissolving 0.01mol of pentahydrate bismuth nitrate into 50ml of 10% dilute nitric acid by volume, adding 0.02mol of citric acid, and uniformly mixing until the bismuth nitrate is completely dissolved; in addition, 0.01mol of ammonium chloride was dissolved in 50ml of distilled waterAnd (4) mixing uniformly in water until the mixture is completely dissolved. Slowly injecting an ammonium chloride solution into a mixed solution of bismuth nitrate pentahydrate and dilute nitric acid of citric acid under the stirring of a constant-temperature magnetic stirrer, uniformly mixing until the solution is in a clear state, adjusting the pH value of the mixed solution to 6 by using ammonia water, continuously heating and stirring at 60 ℃ for 4 hours, pouring the mixed solution into a crucible with a cover, and calcining at 600 ℃ for 3 hours in a muffle furnace to obtain light yellow powder, namely pure Bi₂₄O₃₁Cl₁₀。

(2)g-C₃N₄The preparation of (1): uniformly mixing 3g of melamine and 10 ml of acetic acid (the concentration is 36 percent), placing the mixture into a crucible with a cover, and then calcining the mixture for 2 hours in a muffle furnace at 500 ℃ to obtain light yellow powder, namely pure g-C₃N₄。

(3)MoS₂The preparation of (1): dissolving 80 mg of ammonium molybdate tetrahydrate and 160 mg of thiourea in 50ml of dimethylformamide solvent, magnetically stirring until the reaction raw materials are dissolved to be transparent, then transferring to a 100ml stainless steel hydrothermal reaction kettle with a tetrafluoroethylene lining, reacting for 24 hours at 200 ℃, cooling to room temperature, then carrying out high-speed centrifugation at 10000r/min, washing for 5 times with distilled water to obtain black solid, drying for 24 hours at 60 ℃ in a drying oven to obtain MoS₂。

(4) 2 g of Bi obtained in step (1)₂₄O₃₁Cl₁₀Adding into 40 ml of methanol solution respectively, performing ultrasonic treatment for 1h under 1000KW power, and then adding into Bi₂₄O₃₁Cl₁₀0.02 g, 0.06 g, 0.10 g, and 0.2 g of-C prepared in step (2) were added to the mixed solution with methanol, respectively₃N₄Performing ultrasonic treatment on the powder for 1 hour under 1000KW power, centrifuging the solid and a methanol solution at the rotating speed of 10000r/min, washing the solid with distilled water, centrifuging the washed solid again, repeating the centrifugation for four times to obtain the solid, drying the solid in a drying oven at the temperature of 60 ℃ for 24 hours, cooling and grinding the dried solid to obtain the 1-10% g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

(5) Subjecting 1 g of 5% g-C obtained in step (4)₃N₄/Bi₂₄O₃₁Cl₁₀Sample is added with 20 ml of methanolIn liquid, ultrasonic treatment is carried out for 1h under 1000KW power, and then 5 percent of g-C₃N₄/Bi₂₄O₃₁Cl₁₀0.3g of MoS prepared in step (3) was added to the mixed methanol solution, respectively₂Performing ultrasonic treatment on the powder for 1h under 1000KW power, centrifuging the solid and methanol solution at 10000r/min, washing with distilled water, centrifuging, repeating for four times to obtain solid, drying at 60 deg.C for 48h in a drying oven, cooling, and grinding to obtain 3% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

(6) 1 g of Bi obtained in the step (1)₂₄O₃₁Cl₁₀Adding into 20 ml of methanol solution, carrying out ultrasonic treatment for 1h under 1000KW power, and then adding into Bi₂₄O₃₁Cl₁₀Adding 0.5 g of MoS prepared in step (3) into the mixed solution of methanol₂Performing ultrasonic treatment on the powder for 1h under 1000KW power, centrifuging the solid and methanol solution at 10000r/min, washing with distilled water, centrifuging, repeating for four times to obtain solid, drying at 60 deg.C for 24h in a drying oven, cooling, and grinding to obtain 5% MoS₂/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

EXAMPLES example 2

(1)Bi₂₄O₃₁Cl₁₀The preparation of (1): dissolving 0.01mol of pentahydrate bismuth nitrate into 50ml of 10% dilute nitric acid by volume, adding 0.02mol of citric acid, and uniformly mixing until the bismuth nitrate is completely dissolved; in addition, 0.01mol of ammonium chloride was dissolved in 50ml of distilled water and mixed until completely dissolved. Slowly injecting an ammonium chloride solution into a mixed solution of bismuth nitrate pentahydrate and dilute nitric acid of citric acid under the stirring of a constant-temperature magnetic stirrer, uniformly mixing until the solution is in a clear state, adjusting the pH value of the mixed solution to 5 by using ammonia water, continuously heating and stirring at 80 ℃ for 3 hours, pouring the mixed solution into a crucible with a cover, and calcining at 600 ℃ for 3 hours in a muffle furnace to obtain light yellow powder, namely pure Bi₂₄O₃₁Cl₁₀。

(2)g-C₃N₄The preparation of (1): 3g of melamine were admixed with 10 ml of melamineMixing L acetic acid (concentration: 36%), placing in crucible with cover, calcining in muffle furnace at 500 deg.C for 2 hr to obtain light yellow powder, i.e. pure g-C₃N₄。

(3)MoS₂The preparation of (1): dissolving 60 mg of ammonium molybdate tetrahydrate and 120 mg of thiourea in 36 ml of dimethylformamide solvent, magnetically stirring until the reaction raw materials are dissolved to be transparent, then transferring to a 50ml stainless steel hydrothermal reaction kettle with a tetrafluoroethylene lining, reacting for 24h at 200 ℃, cooling to room temperature, then carrying out high-speed centrifugation at 10000r/min, washing for 5 times with distilled water to obtain black solid, drying for 12h at 100 ℃ in a drying oven to obtain MoS₂。

(4) 1 g of Bi obtained in the step (1)₂₄O₃₁Cl₁₀Adding into 25 ml of methanol solution respectively, performing ultrasonic treatment for 1h under 1000KW power, and then adding into Bi₂₄O₃₁Cl₁₀0.01 g, 0.03g, 0.05 g, and 0.1 g of-C prepared in step (2) were added to the mixed solution with methanol, respectively₃N₄Performing ultrasonic treatment on the powder for 1 hour under 1000KW power, centrifuging the solid and a methanol solution at the rotating speed of 10000r/min, washing the solid with distilled water, centrifuging the washed solid again, repeating the centrifugation for four times to obtain the solid, drying the solid in a drying oven at the temperature of 80 ℃ for 48 hours, cooling and grinding the dried solid to obtain the 1-10% g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

(5) 1.8 g of 5% g-C obtained in step (4)₃N₄/Bi₂₄O₃₁Cl₁₀The sample is added to 40 ml of methanol solution, sonicated for 1h at 1000KW power, then at 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀0.09g of MoS prepared in step (3) was added to the mixed methanol solution separately₂Performing ultrasonic treatment on the powder for 1h under 1000KW power, centrifuging the solid and methanol solution at 10000r/min, washing with distilled water, centrifuging, repeating for four times to obtain solid, drying at 80 deg.C for 24h in a drying oven, cooling, and grinding to obtain 5% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀Composite photocatalysisAnd (3) preparing.

(6) 1 g of Bi obtained in the step (1)₂₄O₃₁Cl₁₀Adding into 20 ml of methanol solution, carrying out ultrasonic treatment for 1h under 1000KW power, and then adding into Bi₂₄O₃₁Cl₁₀Adding 0.5 g of MoS prepared in step (3) into the mixed solution of methanol₂Performing ultrasonic treatment on the powder for 1h under 1000KW power, centrifuging the solid and methanol solution at 10000r/min, washing with distilled water, centrifuging, repeating for four times to obtain solid, drying at 60 deg.C for 24h in a drying oven, cooling, and grinding to obtain 5% MoS₂/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

EXAMPLE 3

(1)Bi₂₄O₃₁Cl₁₀The preparation of (1): dissolving 0.01mol of pentahydrate bismuth nitrate into 50ml of 10% dilute nitric acid by volume, adding 0.02mol of citric acid, and uniformly mixing until the bismuth nitrate is completely dissolved; in addition, 0.01mol of ammonium chloride was dissolved in 50ml of distilled water and mixed until completely dissolved. Slowly injecting an ammonium chloride solution into a mixed solution of bismuth nitrate pentahydrate and dilute nitric acid of citric acid under the stirring of a constant-temperature magnetic stirrer, uniformly mixing until the solution is in a clear state, adjusting the pH value of the mixed solution to 6 by using ammonia water, continuously heating and stirring for 3.5 hours at 60 ℃, pouring the mixed solution into a crucible with a cover, and calcining for 3 hours at 600 ℃ in a muffle furnace to obtain light yellow powder, namely pure Bi₂₄O₃₁Cl₁₀。

(2)g-C₃N₄The preparation of (1): uniformly mixing 3g of melamine and 10 ml of acetic acid (the concentration is 36 percent), placing the mixture into a crucible with a cover, and then calcining the mixture for 2 hours in a muffle furnace at 500 ℃ to obtain light yellow powder, namely pure g-C₃N₄。

(3)MoS₂The preparation of (1): dissolving 45 mg of ammonium molybdate tetrahydrate and 90 mg of thiourea in 27.5 ml of dimethylformamide solvent, magnetically stirring until the reaction raw materials are dissolved to be transparent, then transferring to a 50ml stainless steel hydrothermal reaction kettle with a tetrafluoroethylene lining, reacting for 24h at 200 ℃, cooling to room temperature, then centrifuging at high speed at 10000r/min, washing with distilled water for 5 timesThen obtaining black solid, drying for 18h at 80 ℃ in a drying oven to obtain MoS₂。

(4) 9g of Bi obtained in step (1)₂₄O₃₁Cl₁₀Respectively adding into 200 ml of methanol solution, performing ultrasonic treatment for 1h under 1000KW power, and then adding into Bi₂₄O₃₁Cl₁₀0.09g, 0.27 g, 0.45 g, and 0.9 g of-C prepared in step (2) were added to the mixed solution with methanol, respectively₃N₄Performing ultrasonic treatment on the powder for 1 hour under 1000KW power, centrifuging the solid and a methanol solution at the rotating speed of 10000r/min, washing the solid with distilled water, centrifuging the washed solid, repeating the centrifugation for four times to obtain the solid, drying the solid in a drying oven at 70 ℃ for 36 hours, cooling and grinding the dried solid to obtain the 1-10% g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

(5) 1.5 g of 5% g-C obtained in step (4)₃N₄/Bi₂₄O₃₁Cl₁₀The sample is added to 30 ml of methanol solution, sonicated for 1h at 1000KW power, then at 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀0.105g of MoS prepared in step (3) was added to the methanol mixed solution, respectively₂Performing ultrasonic treatment on the powder for 1h under 1000KW power, centrifuging the solid and methanol solution at 10000r/min, washing with distilled water, centrifuging, repeating for four times to obtain solid, drying at 70 deg.C for 36h in a drying oven, cooling, and grinding to obtain 7% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

(6) 1 g of Bi obtained in the step (1)₂₄O₃₁Cl₁₀Adding into 20 ml of methanol solution, carrying out ultrasonic treatment for 1h under 1000KW power, and then adding into Bi₂₄O₃₁Cl₁₀Adding 0.5 g of MoS prepared in step (3) into the mixed solution of methanol₂Performing ultrasonic treatment on the powder for 1h under 1000KW power, centrifuging the solid and methanol solution at 10000r/min, washing with distilled water, centrifuging, repeating for four times to obtain solid, drying at 60 deg.C for 24h in a drying oven, cooling, and grinding to obtain 5% MoS₂/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

And (3) structural and morphological characterization:

as can be seen from FIG. 1, Bi was produced₂₄O₃₁Cl₁₀Tetragonal system Bi of JCPDS standard card number (No.75-0887)₂₄O₃₁Cl₁₀The diffraction peaks are identical. 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀No g-C in the sample₃N₄Peak, 5% MoS₂/Bi₂₄O₃₁Cl₁₀No MoS in the sample₂Peak of (5%), MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀5% of the total content of the extract is not observed to be g-C₃N₄And MoS₂Mainly due to complexed g-C₃N₄And MoS₂Less in the amount of the compound (A).

As can be seen from FIGS. 2(a), 2(b) and 2(c), 5% MoS was produced₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀In the sample, g-C is successfully compounded₃N₄And MoS₂。

As can be seen from FIG. 3, when Bi is present₂₄O₃₁Cl₁₀And MoS₂Or g-C₃N₄After compounding, the light absorption performance of the sample is obviously improved, wherein MoS is compounded₂The light absorption performance of the rear sample is higher than that of the composite g-C₃N₄The promotion is more remarkable when MoS₂And g-C₃N₄Simultaneous recombination of Bi₂₄O₃₁Cl₁₀The light absorption performance is improved to the maximum, and the light absorption is obvious within the range of 200-800 nm.

As can be seen from FIG. 4, 5% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀The lowest PL peak intensity shows that the photo-excited electron-hole recombination rate of the photocatalyst is the lowest, and the lower the recombination rate is, the photocatalytic activity is improved.

Photocatalytic activity test experiment:

taking the initial concentration as 5 mg.L^-1The rhodamine B (RhB) solution is 100mL or 20 mg.L^-150mL of tetracycline hydrochloride solution is taken as a target degradation product and placed in a 250mL beaker, and then 0.03g of photocatalyst is added into rhodamine B or tetracycline hydrochloride solution and mixed uniformly. Before illumination, the suspension is magnetically stirred in a dark room for 30min to ensure that adsorption-desorption balance is achieved between the photocatalyst and rhodamine B or tetracycline, and then the suspension is placed under a visible light source (250W metal halide lamp) 14cm away from the liquid level for a photocatalytic experiment. The illumination time is 50min, wherein supernatant liquid is taken by a clean rubber head dropper every 10min, the supernatant liquid is placed in a cuvette after centrifugation, the absorbance of the supernatant liquid is measured at the maximum absorption wavelengths of 554nm and 356nm of rhodamine B and tetracycline, and the removal rate D of the rhodamine B or tetracycline solution can be calculated according to the Lambert beer law by the formula (1):

D＝(C₀-C)/C₀×100％＝(A₀’-A)/A₀’×100％ (1)

in the formula: c₀C is the concentration of rhodamine B or tetracycline solution before and after illumination;

A₀', A-absorbance of rhodamine B or tetracycline solution before and after illumination

5% MoS as shown in FIG. 5₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀The catalytic degradation rate of rhodamine B can reach 90% within 50min, and the degradation rate of the composite catalyst to tetracycline can also reach about 88% within 50min (as shown in figure 6), and the composite catalyst is relatively pure Bi₂₄O₃₁Cl₁₀、5％MoS₂/Bi₂₄O₃₁Cl₁₀、5％g-C₃N₄/ Bi₂₄O₃₁Cl₁₀The photocatalytic efficiency is obviously improved, which indicates that MoS is adopted₂And g-C₃N₄Simultaneous recombination of Bi₂₄O₃₁Cl₁₀The activity of the compound is obviously improved.

Claims (1)

1. High-activity MoS₂/g-C₃N₄/Bi₂₄O₃₁Cl₁₀The preparation method of the composite photocatalyst is characterized in thatThe method comprises the following steps:

(1) bi is prepared by taking bismuth nitrate, ammonium chloride and citric acid as raw materials and adopting an improved solution combustion method₂₄O₃₁Cl₁₀

Mixing bismuth nitrate pentahydrate and citric acid, and dissolving in dilute nitric acid to obtain a mixed solution of bismuth nitrate pentahydrate and dilute nitric acid of citric acid, wherein the molar ratio of bismuth nitrate pentahydrate to citric acid is 1: 2; dissolving ammonium chloride in distilled water until the ammonium chloride is completely dissolved to obtain an ammonium chloride solution; under the condition of stirring, adding an ammonium chloride solution into a mixed solution of bismuth nitrate pentahydrate and dilute nitric acid of citric acid, wherein the molar ratio of the bismuth nitrate pentahydrate to the ammonium chloride is 1: 1, uniformly mixing until the solution is in a clear state, and adjusting the pH value of the solution to 5-6 by using ammonia water; heating and stirring for 3-4 h at 60-80 ℃, and then calcining for 3h at 600 ℃ to obtain light yellow powder, namely pure Bi₂₄O₃₁Cl₁₀；

(2) g-C is prepared from melamine and acetic acid by one-step thermal polymerization method₃N₄

Uniformly mixing melamine and acetic acid according to a molar ratio of 10:1, calcining for 2 hours at 500 ℃ to obtain light yellow powder, namely pure g-C₃N₄；

(3) Ammonium molybdate and thiourea are used as raw materials, dimethylformamide is used as a solvent, and a hydrothermal method is adopted to prepare MoS₂

Preparing a mixed solution of ammonium molybdate tetrahydrate and dimethyl formamide of thiourea, wherein the concentration of the mixed solution is 4.8-5.0 g/L, and the mass ratio of the ammonium molybdate tetrahydrate to the thiourea is 1: 2; stirring until the mixed solution of ammonium molybdate tetrahydrate and dimethylformamide of thiourea is in a transparent state; reacting for 24 hours at 200 ℃ in a reaction kettle, and cooling to room temperature; washing with deionized water, centrifuging to obtain a black solid, and drying the black solid at 60-100 ℃ for 12-24 h to obtain MoS₂；

(4) Bi prepared in the step (1)₂₄O₃₁Cl₁₀Adding the mixture into a methanol solution, and performing ultrasonic treatment to obtain Bi with the concentration of 40-50 g/L₂₄O₃₁Cl₁₀A mixed solution with methanol;g-C prepared in the step (2)₃N₄Is added to Bi₂₄O₃₁Cl₁₀In a mixed solution with methanol, wherein g-C₃N₄And Bi₂₄O₃₁Cl₁₀The mass ratio is 0.01-0.1; continuing ultrasonic treatment, centrifuging, washing and centrifuging again to obtain a solid substance; drying the solid matter at 60-80 deg.c for 24-48 hr, cooling and grinding to obtain 1-10% g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst;

(5) 5% g-C prepared in step (4)₃N₄/Bi₂₄O₃₁Cl₁₀Adding the mixture into a methanol solution, and performing ultrasonic treatment to obtain 5% g-C with the concentration of 40-50 g/L₃N₄/Bi₂₄O₃₁Cl₁₀A mixed solution with methanol; the MoS prepared in the step (3) is used₂Adding to 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀In a mixed solution with methanol, wherein, MoS₂With 5% g-C₃N₄/Bi₂₄O₃₁Cl₁₀The mass ratio of (A) to (B) is 0.03-0.07; continuing ultrasonic treatment, centrifuging, washing and centrifuging again to obtain a solid substance; drying the solid substance at 60-80 ℃ for 24-48 h, cooling and grinding to obtain 3-7% MoS₂/5％g-C₃N₄/Bi₂₄O₃₁Cl₁₀A composite photocatalyst is provided.

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