Preparation method and application of eosin co3s4 nanosheet array graphene composite photocatalyst

Abstract

The application provides a preparation method and application of an eosin Co3S4 nanosheet array graphene composite photocatalyst, and the method comprises the following steps: dispersing graphene oxide in deionized water by ultrasonic dispersion to obtain a graphene oxide dispersion solution; dissolving cobalt nitrate in the graphene oxide dispersion solution; adding trisodium citrate and hexamethylenetetramine, uniformly stirring, and then performing low-temperature reflux treatment; collecting the sample by centrifugation, performing washing and vacuum freeze-drying to obtain a cobalt hydroxide nanosheet array-graphene composite material; placing the cobalt hydroxide nanosheet array-graphene composite material and thiourea in a tube furnace, and converting the cobalt hydroxide nanosheet array-graphene composite material into a cobalt sulfide nanosheet array-graphene composite material by using a two-stage calcination method; taking eosin as a photosensitizer, and combining to obtain the eosin Co3S4 nanosheet array graphene composite photocatalyst. The graphene is introduced and the Co3S4 nanosheet array structure is constructed, so that a composite photocatalyst with excellent water photolysis hydrogen production performance is prepared.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photocatalysis, and particularly relates to a preparation method and application of an eosin Co3S4 nanosheet array graphene composite photocatalyst. BACKGROUND

[0002] As a solar energy conversion technology, photocatalysis is considered as a potential alternative method to solve environmental and resource problems due to its low reaction cost, simple operation and mild reaction process. Among them, photocatalytic water splitting technology driven by renewable solar energy is one of the most attractive methods to produce green hydrogen energy. The low efficiency of photocatalytic water splitting to produce hydrogen is mainly due to three reasons: (1) low utilization rate of solar energy; (2) poor separation and transfer efficiency of photo-generated carriers; (3) slow kinetics of hydrogen evolution reaction. Therefore, it is the core of photocatalysis technology to design and construct a photocatalyst to improve light absorption rate, charge separation efficiency and hydrogen production efficiency. It is worth noting that loading a suitable cocatalyst on the surface of the photocatalyst is the most effective and economic way to solve the problems of weak spectral absorption, fast recombination of carriers and insufficient active sites. SUMMARY

[0003] In view of the above situation, the main purpose of the present application is to provide a preparation method and application of an eosin Co3S4 nanosheet array graphene composite photocatalyst to solve the above technical problems.

[0004] The present application provides an eosin Co3S4 nanosheet array graphene composite photocatalyst, which comprises graphene and a Co3S4 nanosheet array, the graphene serving as a skeleton, and the Co3S4 nanosheet array being loaded on the graphene, the mass percentage of the graphene and the Co3S4 nanosheet array being 1% to 30%.

[0005] The present application provides a preparation method of an eosin Co3S4 nanosheet array graphene composite photocatalyst, which comprises the following steps:

[0006] Step 1, dispersing graphene oxide in deionized water under ultrasonic dispersion to obtain a graphene oxide dispersion solution;

[0007] Step 2, dissolving cobalt nitrate in the graphene oxide dispersion solution, adding trisodium citrate and hexamethylene tetramine, stirring uniformly, performing low-temperature reflux treatment after completion of stirring, and then cooling to obtain a sample solution, collecting the sample by centrifugation, washing and vacuum freeze-drying the obtained sample to obtain a cobalt hydroxide nanosheet array-graphene composite photocatalyst;

[0008] Step 3, the cobalt hydroxide nanosheet array-graphene composite material and thiourea are placed in a tube furnace to be converted into a layered cobalt sulfide nanosheet array-graphene composite material by adopting a two-stage calcination method, to obtain a Co3S4 nanosheet array / graphene composite material, the eosin aqueous solution is mixed with the Co3S4 nanosheet array / graphene composite material, and after the dissolution is completed, centrifugal separation is carried out to obtain an eosin Co3S4 nanosheet array graphene composite photocatalyst.

[0009] The application further provides an eosin Co3S4 nanosheet array graphene composite photocatalyst, and the composite photocatalyst is prepared by adopting the preparation method of the eosin Co3S4 nanosheet array graphene composite photocatalyst, and the composite photocatalyst is used for visible light photocatalytic hydrogen evolution.

[0010] Compared with the prior art, the application has the following beneficial effects:

[0011] (1) The Co3S4 nanosheet array / graphene composite material prepared by the application has a low density, a large specific surface area and a large void space, and the combination of GO and transition metal sulfide nanostructures can significantly improve the photocatalytic activity of a semiconductor photocatalyst.

[0012] (2) The low-temperature reflux method and the low-temperature sulfuration method for synthesizing the composite photocatalyst have the characteristics of simple operation, low manufacturing cost, simple production process and macroscopic preparation.

[0013] Additional aspects and advantages of the application will be described in part below, will become apparent from the following description, or will be learned by practicing the application. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is an SEM image of the Co3S4 nanosheet array / graphene composite material prepared by the application;

[0015] Figure 2 is an XPS image of the Co3S4 nanosheet array / graphene composite material prepared by the application;

[0016] Figure 3 is an XRD image of Co(OH)2-GR, Co3S4 and the Co3S4 nanosheet array / graphene composite material prepared by the application;

[0017] Figure 4 is a Raman spectrum image of GO, GR and the Co3S4 nanosheet array / graphene composite material prepared by the application;

[0018] Figure 5 is a hydrogen production activity graph of the Co3S4 nanosheet array / graphene composite material containing different proportions of GR prepared by the application. DETAILED DESCRIPTION

[0019] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein like or similar constituent elements or features may be denoted by like reference characters, and the embodiments of the application described below are illustrative only and not restrictive of the application.

[0020] These and other aspects of embodiments of the present application will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. In the drawings similar elements or features are generally denoted by identical reference characters. In the description that follows, certain embodiments of the application are described in more detail to illustrate the underlying principles of the application. However, it will be apparent to those skilled in the art that the application is not limited to these embodiments.

[0021] Embodiment 1

[0022] Referring to Figures 1 to 4 The embodiment of the present application provides a composite photocatalyst of eosin Co3S4 nanosheet array graphene, which comprises graphene and Co3S4 nanoparticles, wherein the graphene is used as a skeleton, and the Co3S4 nanoparticles are loaded on the graphene, and the mass ratio of the graphene to the Co3S4 nanoparticles is 1% to 30%.

[0023] Embodiment 2

[0024] Referring to Figures 1 to 4 The embodiment of the present application provides a preparation method of a composite photocatalyst of eosin Co3S4 nanosheet array graphene, which is used for preparing the composite photocatalyst of eosin Co3S4 nanosheet array graphene, and the method comprises the following steps.

[0025] Step 1, 1 mg of graphene oxide (GO) is dissolved in 50 mL of deionized water and ultrasonically dispersed for 40 to 60 min to obtain a graphene oxide dispersion solution;

[0026] Step 2, 632.70 mg of cobalt nitrate is dissolved in the graphene oxide dispersion solution, and stirred for 30 min, then 52.30 mg of trisodium citrate and 287.50 mg of hexamethylenetetramine are added and uniformly stirred, and stirred for 60 min, after the stirring is completed, low-temperature reflux treatment is carried out, in the process of low-temperature reflux treatment, the oil bath is uniformly heated, the oil bath temperature is 85℃, and under the condition of vigorous stirring, it is kept for 9 h, and then cooled to room temperature to obtain a sample solution, the sample is collected by centrifugation, and washed thoroughly with deionized water, and vacuum freeze-dried to obtain a single-crystal cobalt hydroxide nanosheet array-graphene composite photocatalyst;

[0027] Step 3, the cobalt hydroxide nanosheet array-graphene (Co(OH)2-GR) composite material and thiourea (CH4N2S) are respectively placed in two porcelain boats according to a mass ratio of 1:5, the thiourea is placed at one end of a gas inlet of a tube furnace, and the cobalt hydroxide nanosheet array-graphene composite material is placed at the other end, and calcination is performed in an argon atmosphere, in the calcination process, a temperature increasing rate is 5℃ / min, the temperature of the tube furnace is first increased to 150℃ and maintained for 30 min, and then increased to 350℃ and maintained for 2 h, so as to be converted into a layered cobalt sulfide nanosheet array-graphene (Co3S4-GR) composite material, after the calcination is completed, the temperature of the tube furnace is reduced to room temperature, the Co3S4 nanosheet array / graphene composite material with a graphene (GR) content of 1% is obtained, and is collected;

[0028] The eosin solution with a concentration of 15 mg is mixed and dissolved with 1 mg of the Co3S4 nanosheet array / graphene composite material, and after the dissolution is completed, centrifugal separation is performed, and the eosin Co3S4 nanosheet array / graphene composite photocatalyst with a graphene content of 1% is obtained.

[0029] Example 3

[0030] Please refer to Figures 1 to 4 The embodiment of the present application provides a preparation method of an eosin Co3S4 nanosheet array / graphene composite photocatalyst, which is used for preparing the above-mentioned eosin Co3S4 nanosheet array / graphene composite photocatalyst, and the method comprises the following steps:

[0031] Step 1, 5 mg of graphene oxide is dissolved in 50 mL of deionized water and ultrasonically dispersed for 40 min to obtain a graphene oxide dispersion liquid;

[0032] Step 2, 652.30 mg of cobalt nitrate is dissolved in the graphene oxide dispersion liquid, and stirred for 30 min, then 55.60 mg of trisodium citrate and 305.70 mg of hexamethylenetetramine are added and uniformly stirred, and stirred for 60 min, after the stirring is completed, low-temperature reflux treatment is performed, in the low-temperature reflux treatment process, the oil bath is uniformly heated, the oil bath temperature is 85℃, and under the condition of vigorous stirring, the temperature is maintained for 9 h, and then cooled to room temperature to obtain a sample solution, the sample is collected by centrifugation, and washed thoroughly with deionized water, and vacuum freeze-dried to obtain a single-crystal cobalt hydroxide nanosheet array-graphene composite photocatalyst;

[0033] Step 3, the cobalt hydroxide nanosheet array-graphene composite material and thiourea are respectively placed in two porcelain boats according to a mass ratio of 1:5, the thiourea is placed at one end of a gas inlet of a tube furnace, and the cobalt hydroxide nanosheet array-graphene composite material is placed at the other end, and calcination is performed in an argon atmosphere, in the calcination process, a temperature increasing rate is 5℃ / min, the temperature of the tube furnace is first increased to 150℃ and maintained for 30 min, and then increased to 350℃ and maintained for 2 h, so as to be converted into a layered cobalt sulfide nanosheet array-graphene (Co3S4-GR) composite material, after the calcination is completed, the temperature of the tube furnace is reduced to room temperature, the Co3S4 nanosheet array / graphene composite material with a graphene content of 5% is obtained, and the Co3S4 nanosheet array / graphene composite material is collected;

[0034] A 15mg eosin aqueous solution is mixed and dissolved with 1mg Co3S4 nanosheet array / graphene composite material, and after the dissolution is completed, centrifugal separation is performed, and the eosin Co3S4 nanosheet array graphene composite photocatalyst with a graphene content of 5% is obtained.

[0035] Example 4

[0036] Please refer to Figures 1 to 4 The embodiment of the present application provides a preparation method of an eosin Co3S4 nanosheet array graphene composite photocatalyst, which is used for preparing the above-mentioned eosin Co3S4 nanosheet array graphene composite photocatalyst, and the method comprises the following steps:

[0037] Step 1, 10mg of graphene oxide is dissolved in 50mL of deionized water and ultrasonically dispersed for 50min to obtain a graphene oxide dispersion liquid;

[0038] Step 2, 727.60mg of cobalt nitrate is dissolved in the graphene oxide dispersion liquid, and stirred for 30min, then 64.50mg of trisodium citrate and 350.50mg of hexamethylenetetramine are added and uniformly stirred, and stirred for 60min, after the stirring is completed, low-temperature reflux treatment is performed, in the low-temperature reflux treatment process, the oil bath is uniformly heated, the oil bath temperature is 90℃, and under the condition of vigorous stirring, the temperature is maintained for 10h, and then cooled to room temperature to obtain a sample solution, the sample is collected by centrifugation, and the sample is washed thoroughly with deionized water and vacuum freeze-dried to obtain a single-crystal cobalt hydroxide nanosheet array-graphene composite photocatalyst;

[0039] Step 3, the cobalt hydroxide nanosheet array-graphene composite material and thiourea are respectively placed in two porcelain boats according to a mass ratio of 1:5, the thiourea is placed at one end of a gas inlet of a tube furnace, and the cobalt hydroxide nanosheet array-graphene composite material is placed at the other end, and calcination is performed in an argon atmosphere, in the calcination process, a temperature increasing rate is 5℃ / min, the temperature of the tube furnace is first increased to 150℃ and maintained for 30 min, and then increased to 350℃ and maintained for 2 h, so as to be converted into a layered cobalt sulfide nanosheet array-graphene (Co3S4-GR) composite material, after the calcination is completed, the temperature of the tube furnace is reduced to room temperature, the Co3S4 nanosheet array / graphene composite material with a graphene content of 10% is obtained, and the Co3S4 nanosheet array / graphene composite material is collected;

[0040] A 15mg eosin aqueous solution is mixed and dissolved with 1mg Co3S4 nanosheet array / graphene composite material, and after the dissolution is completed, centrifugal separation is performed, and the eosin Co3S4 nanosheet array graphene composite photocatalyst with a graphene content of 10% is obtained.

[0041] Example 5

[0042] Please refer to Figures 1 to 4 The embodiment of the present application provides a preparation method of an eosin Co3S4 nanosheet array graphene composite photocatalyst, which is used for preparing the above-mentioned eosin Co3S4 nanosheet array graphene composite photocatalyst, and the method comprises the following steps:

[0043] Step 1, 30mg of graphene oxide is dissolved in 50mL of deionized water and ultrasonically dispersed for 60min to obtain a graphene oxide dispersion liquid;

[0044] Step 2, 702.60mg of cobalt nitrate is dissolved in the graphene oxide dispersion liquid, and stirred for 30min, then 62.40mg of trisodium citrate and 334.30mg of hexamethylenetetramine are added and uniformly stirred, and stirred for 60min, after the stirring is completed, low-temperature reflux treatment is performed, in the low-temperature reflux treatment process, the oil bath is uniformly heated, the oil bath temperature is 90℃, and under the condition of vigorous stirring, the temperature is maintained for 10h, and then cooled to room temperature to obtain a sample solution, the sample is collected by centrifugation, and the sample is washed thoroughly with deionized water, vacuum freeze-dried to obtain a single-crystal cobalt hydroxide nanosheet array-graphene composite photocatalyst;

[0045] Step 3, the cobalt hydroxide nanosheet array-graphene composite material and thiourea (CH4N2S) are respectively placed in two porcelain boats according to a mass ratio of 1:5, the thiourea is placed at one end of a gas inlet of a tube furnace, and the cobalt hydroxide nanosheet array-graphene composite material is placed at the other end, and calcination is performed in an argon atmosphere, in the calcination process, a temperature increasing rate is 5℃ / min, the temperature of the tube furnace is first increased to 150℃ and maintained for 30 min, and then increased to 350℃ and maintained for 2 h, so as to be converted into a layered cobalt sulfide nanosheet array-graphene composite material, after the calcination is completed, the temperature of the tube furnace is reduced to room temperature, and the Co3S4 nanosheet array / graphene composite material with a graphene content of 30% is obtained, and is collected;

[0046] A 15mg aqueous solution of eosin is mixed and dissolved with 1mg of the Co3S4 nanosheet array / graphene composite material, and after the dissolution is completed, centrifugal separation is performed, and the eosin Co3S4 nanosheet array / graphene composite photocatalyst with a graphene content of 30% is obtained.

[0047] Example 6

[0048] The application provides an application of the eosin Co3S4 nanosheet array / graphene composite photocatalyst, and the composite photocatalyst prepared by the preparation method of the eosin Co3S4 nanosheet array / graphene composite photocatalyst is used for visible light photocatalytic hydrogen evolution.

[0049] The specific steps that the composite photocatalyst is used for visible light photocatalytic hydrogen evolution are as follows:

[0050] The prepared photocatalyst is evaluated for the performance of water photolysis hydrogen production by using a sealed quartz reactor (50mL) provided with a sealing rubber sheet. The reaction mixture is composed of 15mg of eosin Y (denoted as EY, as a photosensitizer) and 1mg of the prepared Co3S4 nanosheet array / graphene as a cocatalyst and a mixed solution of H2O / TEOA (5:1, 6mL). Then, the quartz reactor is filled with high-purity argon, and the excess oxygen in the system is discharged, the reaction system is placed in the dark, and stirring is continuously performed for 30min. Subsequently, the quartz tube is placed on a magnetic stirrer, and a xenon lamp (300W, λ100W) is turned on. The quartz tube is placed on a magnetic stirrer, and the reaction is performed, after the light irradiation is performed for 2h, the yield of H2 is analyzed by using a thermal conductivity detector (TCD).

[0051] Further preferably, in the above scheme, the graphene oxide can be prepared by using an improved Hummers method, compared with the graphene oxide prepared by using the other two oxidation-reduction methods, the graphene oxide has high safety, and can obtain a sheet structure of wrinkled graphene oxide, and contains rich oxygen-containing functional groups, has good dispersibility in an aqueous solution and the like.

[0052] The specific preparation process of the graphene oxide is as follows:

[0053] Add 10 g of 400 mesh powdered flake graphite powder to 230 mL of concentrated H2SO4 with moderate stirring, and cool the solution to below 5°C in an ice bath. With stirring, gradually add 30 g of KMnO4, and maintain the temperature of the mixture below 20°C by cooling. Then, heat the solution to 35°C in a water bath, and continue stirring for 2 h. Subsequently, dilute the mixture with 500 ml of deionized water in an ice bath to maintain the temperature below 50°C for 10 min. Shortly after further dilution with 1.5 L of deionized water, then add 80 ml of 30% H2O2 to the mixture, and a yellow-brown product forms with bubbling. Centrifuge the mixture and wash with a 1:10 aqueous HCl solution to remove metal ions, and then wash with deionized water six times to remove the acid. Thereafter, dialyze the mixture for one week, and then dry at 60°C to obtain the final graphene oxide sample.

[0054] Compared with the prior art, the application has the following beneficial effects:

[0055] (1) The Co3S4 nanosheet array-graphene (Co3S4-GR) composite material has the characteristics of low density, large specific surface area and large void space, and the combination of GO and transition metal sulfide nanostructure can significantly improve the photocatalytic activity of the semiconductor photocatalyst.

[0056] (2) The synthesis of the composite photocatalyst by the low-temperature reflux method and the low-temperature sulfuration method has the characteristics of simple operation, low manufacturing cost, simple production process and macroscopic preparation.

[0057] In order to verify the effectiveness of the application, the existing cobalt hydroxide nanosheet array-graphene (Co(OH)2-GR) composite material, blank cobalt sulfide (Co3S4) nanoparticles and the Co3S4 nanosheet array / graphene composite material prepared by the application are used as catalysts for testing, and the specific testing process is as follows:

[0058] Take 5 ml of water (H2O), 1 ml of triethanolamine (TEOA), 15 mg of eosin, and 1 mg of catalyst, and ultrasonically mix them uniformly, and then pass argon gas for half an hour. Place it under visible light for 2 h. Figure 5 As shown in the table, the hydrogen gas generated by the composite photocatalytic decomposition of water of the application is significantly higher than that of Co(OH)2-GR and blank cobalt sulfide, and the Co3S4-10% GR composite material prepared in Example 4 of the application has a GR content of 10%, and the photocatalytic decomposition of water generates 90298 μmol·g -1 ·h -1 of hydrogen gas. It is significantly better than the 17539 μmol·g -1 ·h -1hydrogen and blank Co3S4 nanoparticles produced 50322.99 pmol g -1 ·h -1 hydrogen, thus the present application has higher photocatalytic activity compared to the prior art.

[0059] From the above, it can be seen that the sulfuration of Co(OH)2-GR nanosheets enhances the H2 adsorption capacity of Co3S4-GR composite, increases the surface active sites, and improves the charge separation / transferring, and the nanosheet array structure has the advantages of low density, large specific surface area, and large void space. The water splitting hydrogen production activity of the Co3S4 nanosheet array / graphene composite (Co3S4-GR) under visible light irradiation is significantly higher than that of Co(OH)2-GR and blank Co3S4. The present application can provide a new idea for rationally designing efficient, abundant transition metal sulfide-based cocatalysts on graphene and other two-dimensional platforms, and the photocatalyst is expected to be applied to industrial wastewater treatment, solar hydrogen production, and organic synthesis.

[0060] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0061] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing a Erythrosin Co3S4 nanosheet array graphene composite photocatalyst, characterized in that, The method comprises the following steps: Step 1, ultrasonic dispersion of graphene oxide in deionized water to obtain a graphene oxide dispersion; Step 2, dissolving cobalt nitrate in the graphene oxide dispersion, adding trisodium citrate and hexamethylenetetramine, stirring uniformly, low-temperature reflux treatment after stirring, cooling, obtaining a sample solution, collecting the sample by centrifugation, washing and vacuum freeze-drying the obtained sample to obtain a cobalt hydroxide nanosheet array-graphene composite photocatalyst; Step 3, placing the cobalt hydroxide nanosheet array-graphene composite material and thiourea in a tube furnace to convert into a layered cobalt sulfide nanosheet array-graphene composite material by a two-stage calcination method, wherein the process parameters of the two-stage calcination method are: a heating rate of 5 ℃ / min, a first-stage calcination temperature of 150 ℃, a first-stage temperature holding calcination time of 30 min, a second-stage calcination temperature of 350 ℃, a second-stage temperature holding calcination time of 2 h, and an argon atmosphere; Mixing and dissolving the eosin aqueous solution with the Co3S4 nanosheet array / graphene composite material, centrifuging after dissolving to obtain an eosin Co3S4 nanosheet array / graphene composite photocatalyst.

2. The method for preparing the eosin Co3S4 nanosheet array graphene composite photocatalyst according to claim 1, characterized in that: In step 1, the ionized water is 50 mL, the addition amount of graphene oxide is 1-30 mg, and the ultrasonic treatment time is 40-60 min.

3. The method for preparing a eosin Co3S4 nanosheet array graphene composite photocatalyst according to claim 2, characterized in that: In step 2, the addition amount of cobalt nitrate is 632.70-727.60 mg, the addition amount of trisodium citrate is 52.30-64.50 mg, and the addition amount of hexamethylenetetramine is 287.50-350.50 mg.

4. The method according to claim 1, wherein the method comprises the following steps: 1) synthesizing the graphene; 2) synthesizing the eosin Co3S4 nanosheet array; 3) mixing the graphene and the eosin Co3S4 nanosheet array to obtain the composite photocatalyst. In step 2, the low-temperature reflux is heated by an oil bath, the oil bath temperature is 85-90 ℃, and the oil bath time is 9-10 h.

5. The method for preparing a eosin Co3S4 nanosheet array graphene composite photocatalyst according to claim 1, characterized in that: In step 3, the mass addition ratio of the precursor cobalt hydroxide nanosheet array-graphene composite material and thiourea is 1:

5. 6.The method for preparing a composite photocatalyst of eosin Co 3S 4 nanosheet array and graphene according to claim 1, characterized in that: In step 3, the thiourea is placed at one end of the gas inlet of the tube furnace, and the cobalt hydroxide nanosheet array-graphene composite material is placed at the other end.

7. The method according to claim 1, wherein the method comprises the following steps: 1) synthesizing the graphene nanosheets; 2) synthesizing the eosin Co3S4 nanosheets; 3) mixing the graphene nanosheets and the eosin Co3S4 nanosheets to obtain the eosin Co3S4 nanosheet array graphene composite photocatalyst. In step 3, the mass addition ratio of eosin to the Co3S4 nanosheet array / graphene composite material is 15:

1.

8. Use of a Eosin Y Co3S4 nanosheet array graphene composite photocatalyst, characterized in that, The composite photocatalyst prepared by the method of claim 1-7 is used for visible light photocatalytic hydrogen evolution.

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