Manganese / hydrogenated graphdiyne catalyst, preparation method thereof and application of manganese / hydrogenated graphdiyne catalyst in catalytic ozonation of VOCs

Abstract

The invention discloses a manganese / hydrogenated graphdiyne catalyst, a preparation method thereof and application of the manganese / hydrogenated graphdiyne catalyst in catalytic ozonation of VOCs, and belongs to the technical field of materials. The preparation method of the monatomic manganese / hydrogenated graphdiyne catalyst comprises the following steps: dispersing hydrogenated graphdiyne in a first solvent to obtain a first solution; dispersing soluble manganese salt in a second solvent to obtain a second solution; mixing the first solution and the second solution to obtain dispersion liquid; and drying the dispersion liquid to obtain the monatomic manganese / hydrogenated graphdiyne catalyst, and the monatomic manganese / hydrogenated graphdiyne catalyst provided by the invention is prepared by the preparation method. In addition, the invention also provides an application of the monatomic manganese / hydrogenated graphdiyne catalyst prepared by the preparation method in catalytic ozonation of VOCs (Volatile Organic Compounds). The catalyst prepared by the invention can realize 100% conversion rate of ethyl acetate at room temperature or below room temperature, 12-round high stability and 85% CO2 selectivity.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a manganese / graphene hydrogenation catalyst and a preparation method thereof, and application thereof in catalytic ozonation of VOCs. Background Art

[0002] The rapid development of industrialization and urbanization in the world has produced a large number of volatile organic compounds (VOCs). The pollution comes from petrochemicals, industrial spraying, packaging and printing, and motor vehicle exhaust emissions. These VOCs mainly include benzene, esters, alkanes, olefins, and chlorinated VOCs. Among them, ester pollutants account for the largest proportion, and their relatively stable chemical structure makes them difficult to remove during catalytic oxidation. Under light conditions, secondary pollutants such as O3 and organic aerosols will be generated. They are one of the important precursors to serious air pollution, and will affect the human respiratory system and seriously endanger human health. Therefore, it is urgent to solve the VOCs pollutants from fixed and mobile sources. In recent years, catalytic ozonation has been widely studied as a low-temperature control VOCs technology. Catalytic ozonation has the advantages of wide adaptability to volatile organic compounds, high oxidation efficiency, low reaction temperature, and low energy consumption. It is widely used in sterilization and disinfection and environmental pollutant degradation research. However, the most prominent problem facing this technology is the secondary pollution of ozone.

[0003] As a typical gaseous volatile characteristic and medium polarity, ethyl acetate is an organic solvent for numerous substances. However, there are few studies on the room temperature treatment of ethyl acetate waste gas. Therefore, it is of great significance to adopt appropriate volatile organic compound elimination technology. As a new type of carbon material, hydrogenated graphene has a uniform pore structure with surface heights of sp and sp 2 The conjugated structure, easily adjustable electronic structure and large specific surface area can be used to prepare stable single-atom catalysts.

[0004] However, the degradation effect of pure hydrogenated Graphene on VOCs is not ideal. How to achieve efficient removal of VOCs is a technical problem that needs to be solved by existing technologies. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, provide a manganese / graphene hydrogenation catalyst and its preparation method and application in catalytic ozonation of VOCs, and solve the technical problem of how to achieve efficient removal of VOCs and avoid secondary pollution of O3 in the prior art.

[0006] In order to achieve the above technical objectives, the technical solution of the present invention provides a method for preparing a single-atom manganese / hydrogenated graphene catalyst, comprising the following steps:

[0007] dispersing hydrogenated graphene in a first solvent to obtain a first solution;

[0008] dispersing a soluble manganese salt in a second solvent to obtain a second solution;

[0009] mixing the first solution and the second solution to obtain a dispersion;

[0010] The dispersion is dried to obtain a manganese / graphene hydrogenation catalyst.

[0011] In any embodiment, the first solvent or the second solvent is one of methanol, anhydrous ethanol, ammonia water and water.

[0012] In any embodiment, the soluble manganese salt is one or both of manganese nitrate tetrahydrate and manganese acetate.

[0013] In any embodiment, the drying temperature is 50-60° C., and the drying time is 2-3 hours.

[0014] In any embodiment, the first solution and the second solution are mixed according to a mass ratio of hydrogenated graphene to the soluble manganese salt of (3-5):1 to obtain a dispersion.

[0015] In any embodiment, the mixing of the first solution and the second solution to obtain the dispersion includes: dropping the second solution into the first solution to obtain the dispersion.

[0016] In addition, the present invention also provides a single-atom manganese / graphene hydrogenation catalyst, which is prepared by the above preparation method.

[0017] In addition, the present invention also proposes a manganese / graphene hydrogenated catalyst prepared by the preparation method of the above-mentioned single-atom manganese / graphene hydrogenated catalyst or the use of the above-mentioned manganese / graphene hydrogenated catalyst in catalytic ozonation of VOCs.

[0018] In some embodiments, the VOCs are one or more of ethyl acetate, toluene, propylene or methanol.

[0019] Compared with the prior art, the beneficial effects of the present invention include: the present invention proposes a method for preparing a single-atom manganese / graphene hydrogenated catalyst, characterized in that it includes the following steps: dispersing graphene hydrogenated in a first solvent to obtain a first solution; dispersing a soluble manganese salt in a second solvent to obtain a second solution; mixing the first solution and the second solution to obtain a dispersion; and drying the dispersion to obtain a single-atom manganese / graphene hydrogenated catalyst. The single-atom manganese / graphene hydrogenated catalyst prepared by the present invention can efficiently catalyze the ozonation of VOCs, especially in the catalytic ozonation of ethyl acetate degradation at room temperature, and it also exhibits extremely high catalytic performance of ethyl acetate (EA) below room temperature. Compared with traditional thermal catalytic oxidation technology, this method can achieve a 100% conversion rate of ethyl acetate at room temperature and below room temperature, high stability for 12 rounds, and 85% selectivity for CO2. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a scanning electron microscope image of hydrogenated Graphene and the single-atom manganese / hydrogenated Graphene catalyst prepared in Example 1 of the present invention.

[0021] Figure 2 This is the Raman graph of the single-atom manganese / graphene hydrogenation catalyst prepared in Example 1 of the present invention.

[0022] Figure 3 This is the XRD pattern of the single-atom manganese / hydrogenated graphene catalyst prepared in Example 1 of the present invention.

[0023] Figure 4 This is the XPS graph of the single-atom manganese / hydrogenated graphene catalyst prepared in Example 1 of the present invention.

[0024] Figure 5 This is an activity diagram of the single-atom manganese / graphene hydrogenation catalyst prepared in Example 1 of the present invention and other various carbon materials loaded with single-atom manganese catalyzing the ozonation degradation of ethyl acetate.

[0025] Figure 6 The activity diagram of the single-atom manganese / graphene hydrogenation catalyst and the single-atom copper / graphene hydrogenation catalyst prepared in Example 1 of the present invention for catalyzing the ozonation degradation of ethyl acetate.

[0026] Figure 7 This is an activity diagram of the single-atom manganese / graphene hydrogenation catalyzed ozonation degradation of ethyl acetate prepared in Example 1 of the present invention.

[0027] Figure 8 This is a stability test chart of 10 rounds of ozonation of ethyl acetate catalyzed by single-atom manganese / graphene hydrogenation prepared in Example 1 of the present invention.

[0028] Fig. 9 This is a COx selectivity curve of the single-atom manganese / graphene hydrogenation catalyst prepared in Example 1 of the present invention.

[0029] Fig.10 This is an activity diagram of the ultra-low temperature catalytic ozonation of ethyl acetate by the single-atom manganese / graphene hydrogenation catalyst prepared in Example 1 of the present invention.

[0030] Fig.11 This is an activity diagram of the ozonation degradation of toluene catalyzed by single-atom manganese / graphene hydrogenation prepared in Example 1 of the present invention.

[0031] Fig.12 This is the activity diagram of the single-atom manganese / graphene hydrogenation catalyzed ozonated propylene degradation prepared in Example 1 of the present invention.

[0032] Fig.13 This is an activity diagram of single-atom manganese / graphene hydrogenation catalyzing ozonation of methanol degradation prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0034] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0035] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0036] This specific embodiment provides a method for preparing a single-atom manganese / hydrogenated graphene catalyst, comprising the following steps:

[0037] Dispersing hydrogenated graphene in a first solvent to obtain a first solution; dispersing a soluble manganese salt in a second solvent to obtain a second solution; the soluble manganese salt is one or both of manganese nitrate tetrahydrate and manganese acetate; the first solvent or the second solvent is one of methanol, anhydrous ethanol, ammonia water and water;

[0038] The first solution and the second solution are mixed according to a mass ratio of hydrogenated graphene to the soluble manganese salt of (2-4):1 to obtain a dispersion;

[0039] The dispersion is dried to obtain a single-atom manganese / hydrogenated graphene catalyst; the drying temperature is 50-60° C., and the drying time is 2-3 hours.

[0040] In some embodiments, mixing the first solution and the second solution to obtain the dispersion includes: dropping the second solution into the first solution to obtain the dispersion.

[0041] This specific embodiment also provides a single-atom manganese / graphene hydrogenation catalyst, which is prepared by the above preparation method.

[0042] In addition, this specific embodiment also proposes a single-atom manganese / graphene hydrogenated catalyst prepared by the preparation method of the above-mentioned single-atom manganese / graphene hydrogenated catalyst or the use of the above-mentioned single-atom manganese / graphene hydrogenated catalyst in catalytic ozonation of VOCs.

[0043] In some embodiments, the VOCs are one or more of ethyl acetate, toluene, propylene or methanol.

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] In the present invention, reference is made to “some embodiments”, “this embodiment”, examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0046] If similar descriptions of "first / second" appear in the application documents, the following instructions are added. In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0047] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0048] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0049] Example 1

[0050] This embodiment provides a single-atom manganese / graphene hydrogenation catalyst, which is prepared by the following steps:

[0051] Step 1: First, prepare the carrier hydrogenated graphene. Add 100 mL of pyridine to dissolve the monomer 1,3,5-triethynylbenzene of McLean, transfer it to a constant pressure dropping funnel, adjust the stopcock of the constant pressure dropping funnel, and drip the solution into the above three-necked flask in 4 hours. React at 100°C in the dark for 5 days. After 5 days of reaction, use ultrasound to peel off the polymer on the copper foil and the solution, and evaporate the solvent at 60°C. A yellow-brown powder is obtained, which is hydrogenated graphene (HsGDY). The obtained yellow-brown powder was centrifuged with DMF and acetone until the supernatant was colorless to remove oligomers and unreacted monomers. After drying, it was refluxed with an appropriate amount of 2M hydrochloric acid at 80°C for 6 hours to remove copper substances. The mixture was washed with pure water until the pH value was neutral. An appropriate amount of 2M sodium hydroxide solution was refluxed at 80°C for 6 hours to remove silicon in the polymer. The mixture was washed with pure water until the pH value was neutral, and then centrifuged with DMF, ethanol, and pure water until the supernatant was colorless. The mixture was vacuum dried at 60°C for 12 hours. The product was heated in a tube furnace at a rate of 5°C per minute under an argon atmosphere and calcined at 400°C for 2 hours to obtain a brown powder, namely hydrogenated graphene (HsGDY).

[0052] Step 2: First, 100 mg of hydrogenated graphene powder was weighed with an analytical balance and added to a 100 mL beaker A. A stirring magnet was added to beaker A. Then, 20 mL of anhydrous ethanol solution was measured with a 100 mL measuring cylinder and added to beaker A. Ultrasonic dispersion was performed for 3 min under ultrasonic conditions to obtain a first solution in which hydrogenated graphene was evenly dispersed. Finally, beaker A was transferred to a magnetic stirrer for stirring for later use.

[0053] Step 3: first, use a 100 mL measuring cylinder to measure 20 mL of anhydrous ethanol and add it to beaker B, then use an analytical balance to weigh 22.8 mg of manganese nitrate tetrahydrate (Mn(NO3)2·4H2O) and quickly add it to beaker B, and finally ultrasonically dissolve it for 3 minutes under ultrasonic conditions to fully dissolve the manganese salt to obtain a second solution;

[0054] Step 4: Use a rubber-tipped dropper to add the second solution in beaker B dropwise into the stirring beaker A. After fully stirring at room temperature for 2 hours, seal the mouth of beaker A with tin foil, pierce a small number of air holes with a steel needle, and then transfer to a constant temperature oven and dry at 60°C for 10 hours. After the anhydrous ethanol solution is fully evaporated, a dry and brown-colored single-atom manganese / hydrogenated graphene catalyst sample (i.e., SA Mn HsGDY) is obtained.

[0055] Then, the single-atom manganese / graphene hydrogenation catalyst sample prepared in Example 1 was subjected to the following Figure 1-4 Characterization of surface structure and morphology and analysis of the chemical state of the catalyst surface, Figure 1It can be seen from the scanning electron microscope image that the single-atom manganese / graphene hydrogenation catalyst sample mainly presents irregular particle blocks without specific morphological characteristics. Figure 2 The Raman spectrum results show that after loading the single-atom manganese / hydrogenated graphyne catalyst, the D-band and G-band peak positions are shifted compared with pure hydrogenated graphyne, proving that there is a certain interaction between the metal manganese atom and hydrogenated graphyne. Figure 3 The XRD spectrum of the catalyst showed that there were no characteristic peaks of manganese metal and its oxide, which further indicated that the metal manganese atoms in the catalyst were highly dispersed at the atomic level and no agglomeration occurred. Among them, nanoparticle manganese / hydrogenated graphene (NP Mn HsGDY) was obtained by grinding nanoparticle manganese oxide with the hydrogenated graphene prepared above for ten minutes. Figure 4 The XPS spectrum showed that the manganese atoms on the catalyst surface existed in a divalent form, further proving the successful synthesis of the single-atom manganese / graphene hydrogenation catalyst.

[0056] Application Example 1

[0057] In order to verify the advantages of single-atom manganese / hydrogenated graphene catalyst in the field of VOCs degradation, we applied the prepared single-atom manganese / hydrogenated graphene catalyst to the room temperature catalytic ozonation decomposition activity test of ethyl acetate. The selected test conditions are: the test gas is ethyl acetate, and the concentration of the gas cylinder is 500ppm. The reactor is a quartz tube with an outer diameter of 8mm, an inner diameter of 6mm, and a length of 400mm. The amount of the above catalyst is 100mg, the oxygen flow rate is 30mL / min, the nitrogen balance gas flow rate is 10mL / min, and the ethyl acetate gas flow rate is 10mL / min. The concentration of ozone produced by oxygen is 800ppm, the total gas flow rate is 50mL / min, and the volume space velocity is 30000mLg -1 h -1 The concentration of ethyl acetate in the tail gas was detected and analyzed by gas chromatography, and the reaction temperature during the test was room temperature (25°C).

[0058] The catalytic performance of several other catalysts used for comparison, including activated carbon-loaded manganese, carbon nanotube-loaded manganese, graphene-loaded manganese, and single-atom copper / hydrogenated graphene, were also tested using the above method.

[0059] The conditions during the 12 rounds of stability testing were the same as above.

[0060] Figure 5 and Figure 6The results show that compared with a variety of carbon materials and other transition metals: activated carbon supported manganese (Mn AC), carbon nanotube supported manganese (Mn GNT), graphene (Mn GR) supported manganese, it exhibits 100% catalytic activity, while the catalytic activity of single-atom copper / hydrogenated graphene (i.e. SA Cu HsGDY) is far inferior to that of single-atom manganese / hydrogenated graphene, only about 10%. The preparation of the above comparative samples is similar to the preparation method of single-atom manganese / hydrogenated graphene in Example 1. Activated carbon supported manganese (Mn AC), carbon nanotube supported manganese (Mn GNT), graphene (Mn GR) supported manganese replaces the carrier hydrogenated graphene, while single-atom copper / hydrogenated graphene replaces the manganese nitrate in Example 1 with copper nitrate. Figure 7 The results showed that compared with other catalysts, the single-atom manganese / graphene hydrogenated catalyst nanoparticle manganese / graphene hydrogenated (NP Mn HsGDY) was obtained by grinding nanoparticle manganese oxide with the above prepared graphene hydrogenated for ten minutes. It can achieve 100% catalytic ozonation degradation activity of ethyl acetate at room temperature. Figure 8 The catalytic stability results show that the single-atom manganese / graphene hydrogenation catalyst can achieve stable catalytic ozonation activity of ethyl acetate for 10 cycles at room temperature. Fig. 9 The results show that the single-atom manganese / graphene hydrogenated ozonation of ethyl acetate to produce CO2 has a high selectivity, further proving the excellent activity of the single-atom manganese / graphene hydrogenated catalyst. Fig.10 The results show that the single-atom manganese / graphene hydrogenated ozonation of ethyl acetate has 100% catalytic ozonation degradation activity for ethyl acetate below room temperature (10°C and 0°C).

[0061] Application Example 2

[0062] The catalyst prepared in Example 1 was tested for room temperature catalytic ozonation decomposition activity of toluene. The selected test conditions were: the concentration of the test gas toluene in the cylinder was 500ppm. The reactor was a quartz tube with an outer diameter of 8mm, an inner diameter of 6mm, and a length of 400mm. The amount of the above catalyst was 100mg, the oxygen flow rate was 30mL / min, the nitrogen balance gas flow rate was 36.7mL / min, and the toluene flow rate was 33.3mL / min. The concentration of ozone produced by oxygen was 700ppm, the total gas flow rate was 100mL / min, and the volume space velocity was 60000mLg / min. -1 h -1 The reaction temperature is room temperature 25°C. The above contents are consistent under humid conditions, and the balance of nitrogen is passed into a container filled with water. After the reaction is stable, the concentration of toluene at the reaction outlet is measured by chromatography, and the conversion rate is calculated according to (toluene concentration at the reactor inlet - toluene concentration at the reactor outlet) / (toluene concentration at the reactor inlet) × 100%. Fig.11The results showed that the catalytic ozonation degradation activity of toluene in 70% dry gas (RH=0%) and wet gas (RH=30%) could be achieved at room temperature.

[0063] Application Example 3

[0064] The catalyst prepared in Example 1 was tested for room temperature catalytic ozonation decomposition activity of propylene. The test conditions selected were: the cylinder concentration of the test gas propylene was 500ppm. The reactor was a quartz tube with an outer diameter of 8mm, an inner diameter of 6mm, and a length of 400mm. The amount of the above catalyst was 100mg, the oxygen flow rate was 30mL / min, the nitrogen balance gas flow rate was 36.7mL / min, and the propylene flow rate was 33.3mL / min. The concentration of ozone produced by oxygen was 800ppm, the total gas flow rate was 100mL / min, and the volume space velocity was 30000mL g -1 h -1 The reaction temperature is room temperature 25°C. The above contents are consistent under humid conditions, and the balance of nitrogen is passed into a container filled with water. After the reaction is stable, the concentration of propylene at the reaction outlet is measured by chromatography, and the conversion rate is calculated according to (reactor inlet propylene concentration-reactor outlet propylene concentration) / (reactor inlet propylene concentration)×100%. Fig.12 The results showed that 100% catalytic ozonation degradation activity of dry gas propylene could be achieved at room temperature.

[0065] Application Example 4

[0066] The catalyst prepared in Example 1 was tested for room temperature catalytic ozonation decomposition activity of propylene. The selected test conditions were: the cylinder concentration of test gas methanol was 500ppm. The reactor was a quartz tube with an outer diameter of 8mm, an inner diameter of 6mm, and a length of 400mm. The amount of the above catalyst was 100mg, the oxygen flow rate was 30mL / min, the nitrogen balance gas flow rate was 36.7mL / min, and the methanol flow rate was 33.3mL / min. The concentration of ozone produced by oxygen was 800ppm, the total gas flow rate was 100mL / min, and the volume space velocity was 30000mLg / min. -1 h -1 The reaction temperature is room temperature 25°C. The above contents are consistent under humid conditions, and the balance of nitrogen is passed into a container filled with water. After the reaction is stable, the methanol concentration at the reaction outlet is measured by chromatography, and the conversion rate is calculated according to (methanol concentration at the reactor inlet - methanol concentration at the reactor outlet) / (methanol concentration at the reactor inlet) × 100%. Fig.13 The results showed that 100% catalytic ozonation degradation activity of dry and wet methanol could be achieved at room temperature.

[0067] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a single-atom manganese / graphene hydrogenation catalyst, characterized in that: The following steps are involved: dispersing hydrogenated graphene in a first solvent to obtain a first solution; dispersing a soluble manganese salt in a second solvent to obtain a second solution; mixing the first solution and the second solution to obtain a dispersion; The dispersion is dried to obtain a single-atom manganese / graphene hydrogenation catalyst.

2. The method for preparing the single-atom manganese / graphene hydrogenation catalyst according to claim 1, characterized in that: The first solvent or the second solvent is one of methanol, anhydrous ethanol, ammonia water and water.

3. The method for preparing the single-atom manganese / graphene hydrogenation catalyst according to claim 1, characterized in that: The soluble manganese salt is one or both of manganese nitrate tetrahydrate and manganese acetate.

4. The method for preparing the single-atom manganese / graphene hydrogenation catalyst according to claim 1, characterized in that: The drying temperature is 50-60° C., and the drying time is 2-3 hours.

5. The method for preparing the single-atom manganese / graphene hydrogenation catalyst according to claim 1, characterized in that: The first solution and the second solution are mixed according to a mass ratio of hydrogenated graphene to the soluble manganese salt (3-5):1 to obtain a dispersion.

6. The method for preparing the single-atom manganese / graphene hydrogenation catalyst according to claim 1, characterized in that: The mixing of the first solution and the second solution to obtain the dispersion includes: dropping the second solution into the first solution to obtain the dispersion.

7. A single-atom manganese / graphene hydrogenation catalyst, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6.

8. Use of a manganese / graphene hydrogenated catalyst prepared by the method for preparing the single-atom manganese / graphene hydrogenated catalyst according to any one of claims 1 to 6 or a manganese / graphene hydrogenated catalyst according to claim 7 in catalytic ozonation of VOCs.

9. The use according to claim 8, characterized in that: The VOCs are one or more of ethyl acetate, toluene, propylene or methanol.

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