Reduced graphene / carbon nitride / molybdenum cobalt oxide composite material, and preparation method and application thereof

Abstract

The application discloses a reduced graphene / carbon nitride / molybdenum cobalt oxide composite material and a preparation method and application thereof, and belongs to the technical field of environmental remediation functional materials. The application is characterized in that: by taking nano silicon dioxide as a template, solid molybdenum cobalt oxide is synthesized, and then the solid molybdenum cobalt oxide is loaded on reduced graphene; the loaded material is fully mixed with a nitrogen-containing organic precursor and is calcined; finally, the nano silicon dioxide template is removed, so that the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material is obtained. The preparation method of the composite material is mild, does not involve toxic and harmful raw materials, and the prepared reduced graphene / carbon nitride / molybdenum cobalt oxide composite material has strong anti-interference ability and good cycle stability while keeping the material structure integrity.

Description

Technical Field

[0001] This invention belongs to the field of environmental remediation functional materials technology, specifically relating to a reduced graphene / carbon nitride / molybdenum cobalt oxide composite material, its preparation method, and its application. Background Technology

[0002] Bisphenol A (BPA) is widely used in the production of plastics and resins. Due to its strong lipophilicity and bioaccumulation, it tends to persist in the environment for a long time. BPA is difficult to degrade naturally and poses a threat to ecosystems and human health, especially disrupting the endocrine system, particularly affecting children and pregnant women. Effective removal of BPA has become an important environmental protection issue. Summary of the Invention

[0003] The present invention aims to provide a reduced graphene / carbon nitride / molybdenum cobalt oxide composite material, its preparation method, and its applications. Solid molybdenum cobalt oxide is synthesized using nano-silica as a template, then loaded onto reduced graphene. The loaded material is then thoroughly mixed with a nitrogen-containing organic precursor and calcined. Finally, the nano-silica template is removed to obtain the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material. The preparation method of this composite material is mild and does not involve toxic or harmful raw materials. The resulting reduced graphene / carbon nitride / molybdenum cobalt oxide composite material maintains structural integrity while exhibiting strong anti-interference ability and good cycling stability.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] One of the technical solutions of this invention is to provide a method for preparing a reduced graphene / carbon nitride / molybdenum cobalt oxide composite material, comprising the following steps:

[0006] Nano-silica, cobalt salt, molybdenum salt, and dispersant are mixed evenly in water, and a sodium hydroxide solution is added. After reaction, a solid molybdenum cobalt oxide precursor is obtained. The solid molybdenum cobalt oxide precursor is calcined to obtain solid molybdenum cobalt oxide. The solid molybdenum cobalt oxide and reduced graphene are co-dispersed in water, and after precipitation, reduced graphene / solid molybdenum cobalt oxide is obtained. A nitrogen-containing organic precursor is mixed evenly with the reduced graphene / solid molybdenum cobalt oxide, and after calcination, reduced graphene / carbon nitride / solid molybdenum cobalt oxide is obtained. The reduced graphene / carbon nitride / solid molybdenum cobalt oxide is mixed with a sodium hydroxide solution to remove nano-silica, resulting in the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material.

[0007] In this invention, reduced graphene (rGO), a material with high specific surface area and conductivity, can effectively provide electrons to promote the catalytic reaction. Carbon nitride (g-C3N4), with its abundant nitrogen groups, provides active sites for the catalytic reaction and acts as a bridge in the electron transfer process, improving the stability and reaction efficiency of the catalyst. Molybdenum cobalt oxide (CoMoO4, CM) has good catalytic performance; its cobalt and molybdenum ions can synergistically activate permonosulfate (PMS) to generate sulfate radicals (SO42-), which have strong oxidizing power. •− The presence of hydroxyl radicals (•OH) and other free radicals effectively attacks the benzene ring structure in BPA molecules, breaking their chemical bonds and thus degrading BPA. The reduced graphene / carbon nitride / molybdenum cobalt oxide composite material, through a rationally designed structure, not only enhances its activation ability for PMS but also increases the number of active sites through the synergistic effect of rGO and g-C3N4, thereby improving its BPA removal capacity. Cobalt ions in the molybdenum cobalt oxide play a crucial role in the degradation reaction, accelerating the reaction rate by enhancing the activation effect of PMS.

[0008] Preferably, the cobalt salt is CoSO4•6H2O; the molybdenum salt is (NH4)6Mo7O. 24 ·4H2O; the dispersant is hexadecyltrimethylammonium bromide.

[0009] More preferably, in the preparation step of the solid molybdenum cobalt oxide precursor, the mass ratio of the nano-silica, sodium hydroxide, cobalt salt, molybdenum salt and dispersant is (0.5~0.6):(0.3~0.6):(0.5~0.6):(0.7~0.8):(0.05~0.06).

[0010] Preferably, in the preparation step of the solid molybdenum cobalt oxide precursor, the reaction temperature is 160~180℃ and the time is 8~15h.

[0011] Preferably, the temperature for calcining the solid molybdenum cobalt oxide precursor is 500~550℃, the time is 2~3h, and the heating rate is 5~10℃.

[0012] The calcination process can remove organic impurities from the material and enhance its thermal stability and mechanical strength. At the same time, an appropriate calcination temperature can optimize the crystal structure of the material, increase the number of active sites, and improve its activation ability for PMS.

[0013] Preferably, the mass ratio of the reduced graphene to the solid molybdenum cobalt oxide is (0.3~0.4):(1.0~1.2).

[0014] Preferably, when the solid molybdenum cobalt oxide and the reduced graphene are dispersed together in water, the following steps are taken: first, the solid molybdenum cobalt oxide and the reduced graphene are dispersed in water at 20~25℃, stirring speed of 450~600rpm, and time of 0.5~1h respectively; then, the dispersions are mixed and stirred at 20~25℃ at a stirring speed of 450~600rpm for 6~10h.

[0015] During the stirring process, by controlling parameters such as the amount of reduced graphene and solid molybdenum cobalt oxide, the stirring temperature and rate, it is possible to ensure that the solid molybdenum cobalt oxide is uniformly dispersed on the surface of the reduced graphene, thereby achieving effective material preparation.

[0016] Preferably, the nitrogen-containing organic precursor is melamine.

[0017] More preferably, the mass ratio of the nitrogen-containing organic precursor to the reduced graphene / solid molybdenum cobalt oxide is (0.3~0.4):(0.3~0.4).

[0018] Preferably, the temperature program for calcining the mixture of the nitrogen-containing organic precursor and the reduced graphene / solid molybdenum cobalt oxide is as follows: first, the temperature is increased to 550-570°C at a heating rate of 5-10°C, held for 2-3 hours, then reduced to 23-25°C, and then increased to 520-550°C at a heating rate of 5-10°C, held for 2-3 hours.

[0019] Preferably, in the step of removing nano-silica, the mass ratio of sodium hydroxide to the reduced graphene / carbon nitride / solid molybdenum cobalt oxide is (2~4):(4~5).

[0020] The second technical solution of the present invention provides a reduced graphene / carbon nitride / cobalt molybdenum oxide composite material prepared according to the above-mentioned preparation method of the reduced graphene / carbon nitride / cobalt molybdenum oxide composite material.

[0021] The third technical solution of the present invention provides an application of the above-mentioned reduced graphene / carbon nitride / molybdenum cobalt oxide composite material in activated persulfate.

[0022] The fourth technical solution of the present invention provides an application of the above-mentioned reduced graphene / carbon nitride / molybdenum cobalt oxide composite material in the degradation of bisphenol A by activated persulfate.

[0023] The beneficial technical effects of the present invention are as follows:

[0024] This invention synthesizes a reduced graphene / carbon nitride / molybdenum cobalt oxide composite material through a multi-step method. The reaction conditions are mild, do not involve toxic or harmful raw materials, and the prepared material is efficient, stable, and environmentally friendly.

[0025] The reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared by the method of the present invention has abundant active sites on its surface, thus enabling efficient activation of persulfate and efficient degradation of organic pollutants.

[0026] Through the structural design and optimized preparation method of this invention, the resulting reduced graphene / carbon nitride / molybdenum cobalt oxide composite material exhibits extremely high efficiency in degrading BPA. In experiments, the BPA degradation rate reached 96.5% within 60 minutes, significantly higher than that of molybdenum cobalt oxide, reduced graphene / molybdenum cobalt oxide composite material, and carbon nitride / molybdenum cobalt oxide composite material. Furthermore, this material demonstrates good stability during the reaction process, without significant structural changes or activity reduction, and can be reused multiple times, possessing high practical application value. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The image shows a scanning electron microscope image of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared in Example 1.

[0029] Figure 2 X-ray diffraction patterns of reduced graphene and carbon nitride (A), and X-ray diffraction patterns of the composite materials prepared in Examples 1 and Comparative Examples 2-3 (B).

[0030] Figure 3 The image shows the X-ray photoelectron spectrum of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared in Example 1.

[0031] Figure 4 The catalysts prepared in Example 1 and Comparative Examples 1-3 are used to activate the ability of PMS to degrade BPA.

[0032] Figure 5 The interference resistance of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared in Example 1 during the activation of PMS to degrade BPA.

[0033] Figure 6 Cyclic stability of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared in Example 1 during the activation of PMS to degrade BPA. Detailed Implementation

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0035] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0036] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0038] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0039] Unless otherwise specified, "room temperature" in this invention refers to 23-25°C.

[0040] All raw materials used in this invention were purchased from the market.

[0041] Example 1

[0042] A method for preparing a graphene / carbon nitride / molybdenum cobalt oxide composite material, comprising the following steps:

[0043] (1) Stir 50 mL of water and 0.5 g of nano silica at 25 °C and 600 rpm for 30 min to obtain a nano silica dispersion;

[0044] (2) Dissolve 0.3g of sodium hydroxide in 5mL of ultrapure water at 25℃ to obtain a sodium hydroxide solution;

[0045] (3) Add 0.5g of CoSO4•6H2O and 0.7g of (NH4)6Mo7O 24 A mixed solution was obtained by dissolving 0.05 g of hexadecyltrimethylammonium bromide in 50 mL of ultrapure water at 25 °C using 4H₂O.

[0046] (4) Mix the nano silica dispersion from step (1) with the mixed solution from step (3) to obtain a mixed solution;

[0047] (5) The sodium hydroxide solution from step (2) is slowly added dropwise at 25°C to the mixed solution from step (4) at a rate of 5 drops / min to obtain a mixture;

[0048] (6) Transfer the mixture from step (4) to a reaction vessel, place it in a forced-air drying oven and heat it at 160°C for 8 hours. After cooling to 25°C, filter to obtain the precipitate.

[0049] (7) The precipitate obtained in step (6) was washed three times each with deionized water and anhydrous ethanol, then dried under vacuum at 60°C for 12 hours, and ground through a 200-mesh sieve to obtain a solid molybdenum cobalt oxide precursor.

[0050] (8) The precursor material from step (7) is heated to 500°C at 5°C / min and calcined at that temperature for 2 hours, then cooled to room temperature to obtain solid molybdenum cobalt oxide.

[0051] (9) Add 0.3g of reduced graphene to 50mL of ultrapure water and stir at 25℃ and 600rpm for 0.5h to make the reduced graphene dispersed evenly.

[0052] (10) Add 1.0g of the solid molybdenum cobalt oxide prepared in step (8) to the dispersion in step (9), stir for 6h at 25℃ and 600rpm, and filter to obtain the precipitate;

[0053] (11) The precipitate obtained in step (10) was washed three times each with deionized water and anhydrous ethanol, then dried under vacuum at 60°C for 12 hours, and ground through a 200-mesh sieve to obtain reduced graphene / solid molybdenum cobalt oxide.

[0054] (12) Place 0.3g of melamine and 0.3g of reduced graphene / solid molybdenum cobalt oxide from step (11) into a mortar and grind the mixed powder manually with a pestle by rotating and pressing back and forth to ensure that the powder can fully contact and rub during the grinding process. The grinding time is 20 minutes.

[0055] (13) The mixed powder after grinding in step (12) is heated to 550°C at 5°C / min and kept at that temperature for 2 hours. After cooling to room temperature, it is heated to 520°C at 5°C / min and kept at that temperature for 2 hours to prepare reduced graphene / carbon nitride / solid molybdenum cobalt oxide.

[0056] (14) Dissolve 2g of sodium hydroxide in 50mL of ultrapure water at 25℃ to obtain a sodium hydroxide solution;

[0057] (15) Add 4g of the reduced graphene / carbon nitride / solid molybdenum cobalt oxide from step (13) to the sodium hydroxide solution from step (14) and stir for 8h at 25°C and 600rpm.

[0058] (16) The precipitate obtained in step (15) was washed three times each with deionized water and anhydrous ethanol, then dried under vacuum at 60°C for 12 hours, and ground through a 200-mesh sieve to obtain the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material (GR-CM).

[0059] The materials prepared in Example 1 were characterized and tested using scanning electron microscopy, X-ray diffraction patterns, and X-ray photoelectron spectroscopy. The results are as follows: Figures 1-3 As shown.

[0060] Figure 1 This is a scanning electron microscope image of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared in Example 1 of this invention; Figure 1 It can be seen that the microstructure of the prepared reduced graphene / carbon nitride / molybdenum cobalt oxide composite material is a layered structure, with molybdenum cobalt oxide nanoparticles attached to the surface and between the layers, indicating that the material has been successfully synthesized.

[0061] Figure 2 X-ray diffraction patterns (A) of reduced graphene and carbon nitride, and X-ray diffraction patterns (B) of the composite materials prepared in Examples 1 and Comparative Examples 2-3; Figure 2 It can be seen that the structure of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared by the present invention not only contains the characteristic peaks of reduced graphene and carbon nitride, but also contains the characteristic peaks of molybdenum cobalt oxide nanoparticles, indicating that the material has been successfully synthesized.

[0062] Figure 3 X-ray photoelectron spectroscopy of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material prepared in Example 1 of this invention; by Figure 3 It can be seen that the characteristic elements of the prepared reduced graphene / carbon nitride / molybdenum cobalt oxide composite material not only contain C and N elements of reduced graphene and carbon nitride, but also Co, Mo and O elements of molybdenum cobalt oxide nanoparticles, indicating that the material has been successfully synthesized.

[0063] Application Example 1

[0064] A method for activating persulfate to degrade bisphenol A (BPA) in water:

[0065] Experimental Group 1:

[0066] Add 100 mL of 10 mg / L BPA solution to an Erlenmeyer flask, and then add 0.01 g of GR-CM prepared in Example 1 and 0.01 g of persulfate (PMS) to the system to start the reaction. Collect 1.0 mL of the reaction solution at the set time (60 min), filter it using a nylon syringe filter, and then quickly add 0.5 mL of the reaction solution to a brown vial containing 0.5 mL of methanol. The test results are as follows... Figure 4 As shown.

[0067] Experimental Group 2:

[0068] Add 100 mL of 10 mg / L BPA solution to an Erlenmeyer flask, and then add 0.01 g of the GR-CM prepared in Example 1 to start the reaction. Collect 1.0 mL of the reaction solution at the set time (60 min), filter it using a nylon syringe filter, and then quickly add 0.5 mL of the reaction solution to a brown vial containing 0.5 mL of methanol. The test results are shown below. Figure 4 GR-CM / PMS and GR-CM.

[0069] Figure 4 This includes graphs showing the effectiveness of bisphenol A degradation in experimental groups one and two. Figure 4 Test results show that the GR-CM prepared in Example 1 can efficiently activate persulfate to degrade bisphenol A in water, with a bisphenol A degradation rate of up to 96.5% within 60 min; the adsorption rate of bisphenol A by the prepared GR-CM within 60 min is only 11.76%, indicating that GR-CM cannot rapidly enrich BPA on the catalyst surface.

[0070] Experimental Group 3:

[0071] Add 100 mL of a 10 mg / L BPA solution to an Erlenmeyer flask, and then add coexisting ions of different concentrations to the system (see [link to Erlenmeyer flask] for details on the added coexisting ions and their concentrations in the system). Figure 5 Then, 0.01g of GR-CM prepared in Example 1 and 0.01g of persulfate (PMS) were added to start the reaction. At the set time (60 min), 1.0 mL of the reaction solution was collected, filtered using a nylon syringe filter, and 0.5 mL of the reaction solution was quickly added to a brown vial containing 0.5 mL of methanol. The test results are as follows: Figure 5 As shown in the figure. Experimental results indicate that the presence of coexisting ions does not significantly affect the catalytic performance of GR-CM, demonstrating its strong anti-interference ability.

[0072] Experimental Group 4:

[0073] After completing Experiment 1, the GR-CM was eluted alternately with methanol and ultrapure water and then vacuum dried at 60°C. Five rounds of experiments were conducted to continuously degrade BPA using activated PMS. The test results are as follows: Figure 6As shown in the figure. Experimental results show that after five consecutive rounds of experiments, the removal rate of BPA in the GR-CM / PMS system remained above 90%, indicating that GR-CM has good stability.

[0074] Comparative Example 1

[0075] A method for preparing a molybdenum cobalt oxide material, comprising the following steps:

[0076] Similar to Example 1, except that the solid molybdenum cobalt oxide obtained in step (8) is processed in steps (15) and (16) to prepare molybdenum cobalt oxide (CoMoO4, CM).

[0077] The same testing method as in Experiment 1 of Application Example 1 was used, and the test results are shown below. Figure 4 The CM / PMS assay showed that the degradation rate of bisphenol A was 53.21% within 60 minutes.

[0078] Comparative Example 2

[0079] A method for preparing a reduced graphene / molybdenum cobalt oxide composite material, comprising the following steps:

[0080] Similar to Example 1, except that the reduced graphene / solid molybdenum cobalt oxide in step (11) is processed in steps (15) and (16) to prepare the reduced graphene / molybdenum cobalt oxide composite material (rGO / CoMoO4, R-CM).

[0081] The same testing method as in Experiment 1 of Application Example 1 was used, and the test results are shown below. Figure 4 The results showed that the degradation rate of bisphenol A was 54.89% within 60 minutes using R-CM / PMS.

[0082] Comparative Example 3

[0083] A method for preparing a carbon nitride / molybdenum cobalt oxide composite material, comprising the following steps:

[0084] Same as Example 1, except that after step (8), steps (12) to (16) are performed directly to prepare carbon nitride / cobalt molybdenum oxide composite material (g-C3N4 / CoMoO4, G-CM).

[0085] The same testing method as in Experiment 1 of Application Example 1 was used, and the test results are shown below. Figure 4 The study used G-CM / PMS to determine the degradation rate of bisphenol A (BPA) within 60 minutes.

[0086] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a reduced graphene / carbon nitride / molybdenum cobalt oxide composite material, characterized in that, Includes the following steps: Nano-silica, cobalt salt, molybdenum salt, and dispersant are mixed evenly in water, and a sodium hydroxide solution is added. After reaction, a solid molybdenum cobalt oxide precursor is obtained. The solid molybdenum cobalt oxide precursor is calcined to obtain solid molybdenum cobalt oxide. The solid molybdenum cobalt oxide and reduced graphene are co-dispersed in water, and after precipitation, reduced graphene / solid molybdenum cobalt oxide is obtained. A nitrogen-containing organic precursor is mixed evenly with the reduced graphene / solid molybdenum cobalt oxide, and after calcination, reduced graphene / carbon nitride / solid molybdenum cobalt oxide is obtained. The reduced graphene / carbon nitride / solid molybdenum cobalt oxide is mixed with a sodium hydroxide solution to remove nano-silica, resulting in the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material. The solid molybdenum cobalt oxide is CoMoO4; The mass ratio of the reduced graphene to the solid molybdenum cobalt oxide is (0.3~0.4):(1.0~1.2); The mass ratio of the nitrogen-containing organic precursor to the reduced graphene / solid molybdenum cobalt oxide is (0.3~0.4):(0.3~0.4).

2. The method for preparing the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material according to claim 1, characterized in that, The cobalt salt is CoSO4•6H2O; the molybdenum salt is (NH4)6Mo7O. 24 ·4H2O; the dispersant is hexadecyltrimethylammonium bromide; in the preparation step of the solid molybdenum cobalt oxide precursor, the mass ratio of the nano-silica, sodium hydroxide, cobalt salt, molybdenum salt and dispersant is (0.5~0.6):(0.3~0.6):(0.5~0.6):(0.7~0.8):(0.05~0.06).

3. The method for preparing the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material according to claim 1, characterized in that, In the preparation step of the solid molybdenum cobalt oxide precursor, the reaction temperature is 160~180℃ and the time is 8~15h.

4. The method for preparing the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material according to claim 1, characterized in that, The solid molybdenum cobalt oxide precursor is calcined at a temperature of 500~550℃ for 2~3 hours, with a heating rate of 5~10℃.

5. The method for preparing the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material according to claim 1, characterized in that, When the solid molybdenum cobalt oxide and the reduced graphene are dispersed together in water, the following steps are taken: first, the solid molybdenum cobalt oxide and the reduced graphene are dispersed in water at 20~25℃, stirring speed of 450~600rpm, and time of 0.5~1h respectively; then, the dispersions are mixed and stirred at 20~25℃ at a stirring speed of 450~600rpm for 6~10h.

6. The method for preparing the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material according to claim 1, characterized in that, The nitrogen-containing organic precursor is melamine.

7. The method for preparing the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material according to claim 1, characterized in that, The temperature program for calcining the nitrogen-containing organic precursor and the reduced graphene / solid molybdenum cobalt oxide mixture is as follows: first, the temperature is increased to 550-570°C at a rate of 5-10°C, held for 2-3 hours, then decreased to 23-25°C, and then increased to 520-550°C at a rate of 5-10°C, held for 2-3 hours; and / or, in the step of removing nano-silica, the mass ratio of sodium hydroxide to the reduced graphene / carbon nitride / solid molybdenum cobalt oxide is (2-4):(4-5).

8. A reduced graphene / carbon nitride / cobalt molybdenum oxide composite material prepared by the method of preparing the reduced graphene / carbon nitride / cobalt molybdenum oxide composite material according to any one of claims 1 to 7.

9. The application of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material according to claim 8 in the activation of persulfate.

10. The application of the reduced graphene / carbon nitride / molybdenum cobalt oxide composite material of claim 8 in the degradation of bisphenol A by activated persulfate.

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