Oxygen-Rich Carbon Quantum Dots and Their Synthesis and Application in Electrocatalytic Production of Hydrogen Peroxide

Abstract

The present invention relates to oxygen-rich carbon quantum dots, their synthesis, and their application in electrocatalytic production of hydrogen peroxide. The specific synthesis process is as follows: (1) Take a phenolic compound and disperse it in a solvent to obtain a phenolic precursor solution; (2) Transfer the phenolic precursor solution to a reaction kettle for solvothermal reaction. After the obtained reaction product is filtered, dried, and ground, a crude product of carbon quantum dot powder is obtained; (3) After the crude product of carbon quantum dot powder is sufficiently ground, it is calcined under the protection of an inert gas to obtain the target product, oxygen-rich carbon quantum dots. Compared with the prior art, the preparation method of the present invention produces no waste acid or waste, the raw material cost is low, and the obtained carbon material has a high selectivity for the two-electron reaction path of the oxygen reduction process.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic materials, and relates to an oxygen-rich carbon quantum dot, its synthesis and application in electrocatalytic production of hydrogen peroxide. Background Art

[0002] Common disinfectants on the market are highly irritating and corrosive due to the presence of chlorine and manganese elements, which will exacerbate environmental pollution; disinfectants are important for eliminating viruses and maintaining the health and safety of the living environment for humans. Hydrogen peroxide has a simple chemical structure and only contains H and O elements. It is a clean, efficient and atom-economic strong oxidant. Nowadays, more than 95% of hydrogen peroxide in the world is produced by the anthraquinone method. The whole production process requires a large amount of organic solvents and stabilizers, with many reaction steps, high energy consumption and high costs. Moreover, the anthraquinone method has the potential risk of explosion during the transportation and storage of hydrogen peroxide, which does not meet the production expectations of green, safe and low cost.

[0003] In the process of electrochemical oxygen reduction, the use of electrocatalysts promotes more oxygen to generate hydrogen peroxide through a two-electron reaction path. Moreover, the electrochemical synthesis method has mild reaction conditions and is expected to achieve large-scale industrial production of hydrogen peroxide, thus avoiding the deficiencies of the anthraquinone method. However, the design and development of new electrocatalysts with low cost, strong stability and high selectivity for hydrogen peroxide are problems that need to be solved urgently. The earliest catalysts used for the two-electron process to produce hydrogen peroxide are noble metal materials, but they are short of resources, high in cost, easy to oxidize or inactivate due to poisoning, and only a few metals or their alloys have high selectivity, such as Au, Ag, Cu-Hg, Ag-Hg, etc.; some studies have chelated non-noble metals with carbon materials and found that several common metals such as Cu, Ni, Co, Cr and Mn loaded on carbon materials still show relatively prominent two-electron catalytic performance. Therefore, it is proposed that pure carbon materials can also generate catalytic sites for the two-electron reduction of oxygen after certain treatments. However, in the synthesis process of existing oxygen-rich carbon quantum dot materials, a large amount of irritating organic solvents are used, and carriers such as carbon black or carbon nanotubes need to be loaded to achieve better performance. The present invention is precisely proposed based on this. Summary of the Invention

[0004] The purpose of the present invention is to provide an oxygen-rich carbon quantum dot, its synthesis and application in electrocatalytic production of hydrogen peroxide. The preparation method produces no waste acid or waste, has low raw material costs, and the obtained carbon material has high selectivity for the two-electron reaction path of the oxygen reduction process.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] One of the technical solutions of the present invention provides a preparation method of an oxygen-rich carbon quantum dot, including the following steps:

[0007] (1) Disperse phenolic compounds in a solvent to obtain a phenolic precursor solution;

[0008] (2) Transfer the phenolic precursor solution to a reaction kettle for solvothermal reaction. After the obtained reaction product is filtered, dried, and ground, a crude product of carbon quantum dot powder is obtained;

[0009] (3) After the crude product of carbon quantum dot powder is sufficiently ground, it is calcined under the protection of an inert gas to obtain the target product, oxygen-rich carbon quantum dots.

[0010] Further, in step (1), the phenolic compounds are selected from at least one of phenol, catechol, resorcinol, hydroquinone, phloroglucinol, 1,2,3-benzenetriol, and 1,2,4-benzenetriol.

[0011] Further, in step (1), the solvent is one or a combination of several of water, ethanol, N,N-dimethylformamide, acetone, acetonitrile, formamide, or toluene.

[0012] Further, in step (1), the concentration of the phenolic compound in the phenolic precursor solution is 2-20 mg / mL.

[0013] Further, in step (2), the temperature of the solvothermal reaction is 130-210 °C, and the time is 6-12 h.

[0014] Further, in step (3), the calcination temperature is 250-350 °C, and the time is 3-5 h.

[0015] The second technical solution of the present invention provides an oxygen-rich carbon quantum dot, which is prepared by using any one of the above preparation methods.

[0016] The third technical solution of the present invention provides the application of oxygen-rich carbon quantum dots in electrocatalytic production of hydrogen peroxide. Specifically, it is used to prepare a highly selective electrocatalytic oxygen reduction hydrogen peroxide carbon quantum dot catalyst to perform a two-electron electrocatalytic oxygen reduction reaction to electrocatalytically reduce oxygen to hydrogen peroxide.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) The present invention uses inexpensive and easily available phenolic benzene ring compounds as raw materials, and utilizes the rich oxygen-containing functional groups in the raw materials themselves to prepare oxygen-rich carbon quantum dots. In addition, the contents of C=O and C-O functional groups are accurately regulated by the polarity of different solvents, so as to prepare oxygen-rich carbon quantum dots with excellent oxygen reduction catalytic performance and apply them to electrocatalytic production of hydrogen peroxide.

[0019] (2) The oxygen-rich carbon quantum dot catalytic material prepared by the present invention has a high oxygen content. X-ray photoelectron spectroscopy shows that the oxygen content on the surface of the material obtained in Step 4 is 38.8 at.%, the selectivity for hydrogen peroxide is as high as 84.6%, and the number of transferred electrons is 2.3 at 0.60 V (vs RHE).

[0020] (3) The preparation process disclosed in the present invention aims to be environmentally friendly, without using toxic reagents, and has low cost. By only changing the solvent polarity and synthesis process to regulate the oxygen content and types, the obtained oxygen-rich carbon quantum dot catalytic material has excellent electrocatalytic performance, and the average number of electron transfers is an ideal two-electron process.

[0021] (4) The present invention proposes an unexplored solvent engineering strategy, that is, an innovation in the principle of a brand-new synthesis process. In order to deeply understand the engineering mechanism of solvent reagents and analyze the relationship between the nature of oxygen-containing functional groups on the surface of oxygen-rich carbon quantum dots and the two-electron selectivity, a high-performance oxygen-rich quantum dot for electrocatalytic applications is prepared through a direct solvent engineering strategy without any complex post-treatment. Description of the Drawings

[0022] Figure 1 TEM image of the oxygen-rich carbon quantum dot catalytic material prepared in Example 4;

[0023] Figure 2 FT-IR spectrum of the oxygen-rich carbon quantum dot catalytic material prepared in Example 4;

[0024] Figure 3 XPS spectrum of the oxygen-rich carbon quantum dot catalytic material prepared in Example 4;

[0025] Figure 4 Graph of the number of transferred electrons and hydrogen peroxide selectivity of the oxygen-rich carbon quantum dot catalytic material prepared in Example 4;

[0026] Figure 5 Graph of the hydrogen peroxide selectivity of the oxygen-rich carbon quantum dot catalytic materials with or without calcination in Examples 1 and 2;

[0027] Figure 6 Graph of the hydrogen peroxide selectivity of the oxygen-rich carbon quantum dot catalytic materials with or without ammonia catalyst addition in Examples 2 and 3. Detailed Embodiments

[0028] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0029] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0030] Example 1:

[0031] In this embodiment, the synthesis method of oxygen-rich carbon quantum dots includes the following steps:

[0032] Prepare carbon quantum dot materials. Dissolve 0.5 g of phloroglucinol in 50 mL of ethanol, ultrasonically disperse it evenly, then transfer the solution to a polytetrafluoroethylene high-temperature autoclave, and heat-treat it at 180 °C for 8 hours. Cool the reaction solution to room temperature, filter it with water and ethanol using a 0.22 μm organic filter membrane to obtain a carbon quantum dot filtrate. The filtrate is rotary evaporated and dried to obtain a powdery solid. After removing the solvent with a rotary evaporator and drying the filtrate, a powdery solid is obtained.

[0033] Take 1 mg of the material prepared in the above step and dissolve it in 200 μL of water and 800 μL of isopropanol solution, add 50 μL of binder Nafion solution, ultrasonically disperse it until uniform, take 5 μL and drop-coat it on the surface of a rotating ring-disk electrode with an area of 0.19625 cm 2 and let it dry naturally. Aerate for 1 h to make the electrolyte reach the oxygen saturation state. Use a three-electrode system to test and analyze the two-electron oxygen reduction performance of the carbon quantum dot catalyst prepared in this embodiment. First, perform 20 cyclic voltammetry tests at a scan rate of 50 mV / s, with the scanning range from -0.2 to 0.8 V (vs. SCE). After the test, turn on the rotation control switch, set the rotation speed to 1600 rpm, apply a potential of -0.4 V (vs. SCE) to the ring electrode, and finally apply 0.25 V (vs. SCE) to collect the ring-disk current data. After obtaining the ring-disk current data, calculate the number of transferred electrons and the hydrogen peroxide selectivity of this embodiment according to the formula.

[0034] Example 2:

[0035] In this embodiment, the synthesis method of oxygen-rich carbon quantum dots includes the following steps:

[0036] (1) Prepare pure carbon quantum dot materials. Disperse 0.5 g of phloroglucinol in 45 mL of ethanol and ultrasonically disperse it evenly. Then transfer the solution to a polytetrafluoroethylene high-temperature autoclave and heat-treat it at 180 °C for 10 hours. Cool the reaction solution to room temperature, and use a 0.22 μm organic filter membrane to filter it with water and ethanol to obtain a carbon quantum dot filtrate. The filtrate is rotary evaporated and dried to obtain a powdery solid.

[0037] (2) Grind the powdered carbon quantum dots obtained in (1) evenly, keep them at 350 °C in flowing N2 for 4 hours, with a heating rate of 5 °C / min. After the reaction ends, wait for the temperature to drop to room temperature, take out the sample and grind it into a powder.

[0038] Take 1 mg of the material prepared in step (2) and dissolve it in 200 μL of water and 800 μL of isopropanol solution, add 50 μL of binder Nafion solution, ultrasonically disperse it until uniform, take 5 μL and drop-coat it on the surface of a rotating ring-disk electrode of 0.19625 cm 2 and let it dry naturally. Ventilate for 1 h to make the electrolyte reach the oxygen saturation state. Use a three-electrode system to test and analyze the two-electron oxygen reduction performance of the carbon quantum dot catalyst prepared in this example. First, perform 20 cycles of cyclic voltammetry tests at a scan rate of 50 mV / s, with a scanning range of -0.2 to 0.8 V (vs. SCE). After the test ends, turn on the rotation control switch, set the rotation speed to 1600 rpm, apply a potential of -0.4 V (vs. SCE) to the ring electrode, and finally apply 0.25 V (vs. SCE) to collect the ring-disk current data. After obtaining the ring-disk current data, calculate the number of transferred electrons and the hydrogen peroxide selectivity of this example according to the formula.

[0039] Example 3:

[0040] In this example, the synthesis method of oxygen-rich carbon quantum dots and their application in electrocatalytic hydrogen peroxide production include the following steps:

[0041] Dissolve 0.5 g of phloroglucinol in 50 mL of ethanol, then add 5 mL of ammonia water and ultrasonically disperse it evenly. Transfer it to a high-temperature and high-pressure reaction kettle and heat-treat it at 150 °C for 12 hours. After the reaction solution cools to room temperature, use a 0.22 μm organic filter membrane to filter by suction with water and ethanol to obtain the carbon quantum dot filtrate. Evaporate the filtrate by rotary evaporation and dry it to obtain a powdered solid. Grind the obtained powdered carbon quantum dots evenly, keep them at 350 °C in flowing N2 for 4 hours, with a heating rate of 5 °C / min. After the reaction ends, wait for the temperature to drop to room temperature, take out the sample and grind it into a powder.

[0042] Take 1 mg of the material prepared in the above steps and dissolve it in 200 μL of water and 800 μL of isopropanol solution, add 50 μL of binder Nafion solution, ultrasonically disperse it until uniform, take 5 μL and drop-coat it on the surface of a rotating ring-disk electrode of 0.19625 cm 2The rotating ring-disk electrode surface is air-dried naturally, and the electrolyte is aerated for 1 h to reach the oxygen saturation state. The two-electron oxygen reduction performance of the carbon quantum dot catalyst prepared in this example is tested and analyzed using a three-electrode system. First, 20 cycles of cyclic voltammetry tests are performed at a scan rate of 50 mV / s, and the scanning range is -0.2 to 0.8 V (vs. SCE). After the test is completed, the rotation control switch is turned on, the rotation speed is set to 1600 rpm, a potential of -0.4 V (vs. SCE) is applied to the ring electrode, and finally, 0.25 V (vs. SCE) is applied to collect the ring-disk current data. After obtaining the ring-disk current data, the number of transferred electrons and the hydrogen peroxide selectivity of this example are calculated according to the formula.

[0043] Example 4:

[0044] In this example, the synthesis method of oxygen-rich carbon quantum dots and their application in electrocatalytic hydrogen peroxide production include the following steps:

[0045] Dissolve 0.5 g of phloroglucinol in a mixed solvent of ethanol and acetone with a ratio of 1:1 and disperse it evenly by ultrasonic treatment. Then transfer the solution to a 100 mL polytetrafluoroethylene high-temperature and high-pressure autoclave and heat-treat it at 180 °C for 10 h. The reaction solution is cooled to room temperature, and a 0.22 μm organic filter membrane is used. The filtrate is obtained by washing and suction filtration with water and ethanol, and the filtrate is dried at 60 °C at room temperature to obtain carbon quantum dot powder. The obtained powdered carbon quantum dots are ground evenly and kept warm in flowing N2 at 350 °C for 4 hours, with a heating rate of 5 °C / min. After the reaction is completed, when the temperature drops to room temperature, the sample is taken out and ground into a powder.

[0046] Take 1 mg of the carbon quantum dot powder material prepared in the above steps and dissolve it in 200 μL of water and 800 μL of isopropanol solution, add 50 μL of the binder Nafion solution, and disperse it evenly by ultrasonic treatment. Take 5 μL and drop-coat it on the surface of a 0.19625 cm 2 The rotating ring-disk electrode surface is air-dried naturally, and the electrolyte is aerated for 1 h to reach the oxygen saturation state. The two-electron oxygen reduction performance of the carbon quantum dot catalyst prepared in this example is tested and analyzed using a three-electrode system. First, 20 cycles of cyclic voltammetry tests are performed at a scan rate of 50 mV / s, and the scanning range is -0.2 to 0.8 V (vs. SCE). After the test is completed, the rotation control switch is turned on, the rotation speed is set to 1600 rpm, a potential of -0.4 V (vs. SCE) is applied to the ring electrode, and finally, 0.25 V (vs. SCE) is applied to collect the ring-disk current data. After obtaining the ring-disk current data, the number of transferred electrons and the hydrogen peroxide selectivity of this example are calculated according to the formula.

[0047] Example 5:

[0048] In this example, the synthesis method of oxygen-rich carbon quantum dots and their application in electrocatalytic hydrogen peroxide production include the following steps:

[0049] Dissolve 0.5 g of 1,2,3-benzenetriol in 50 mL of ethanol, then add 5 mL of ammonia water and disperse it evenly by ultrasonic treatment. Transfer it to a high-temperature and high-pressure reaction kettle, heat-treat it at 150 °C for 10 hours. After the reaction solution is cooled to room temperature, use a 0.22-μm organic filter membrane to filter by suction with water and ethanol to obtain the carbon quantum dot filtrate. Evaporate the filtrate by rotary evaporation and dry it to obtain a powdery solid. Grind the obtained powdery carbon quantum dots evenly, keep them warm in flowing N2 at 350 °C for 4 hours, with a heating rate of 5 °C / min. After the reaction is completed, wait for the temperature to drop to room temperature, take out the sample and grind it into a powdery state.

[0050] Take 1 mg of the material prepared in the above steps and dissolve it in 200 μL of water and 800 μL of isopropanol solution, add 50 μL of binder Nafion solution, disperse it evenly by ultrasonic treatment, take 5 μL and drop-coat it on the surface of a rotating ring-disk electrode of 0.19625 cm 2 and let it dry naturally. Ventilate for 1 h to make the electrolyte reach the oxygen saturation state. Use a three-electrode system to test and analyze the two-electron oxygen reduction performance of the carbon quantum dot catalyst prepared in this example. First, perform 20 cycles of cyclic voltammetry tests at a scan rate of 50 mV / s, with a scan range of -0.2 to 0.8 V (vs. SCE). After the test is completed, turn on the rotation control switch, set the rotation speed to 1600 rpm, apply a potential of -0.4 V (vs. SCE) to the ring electrode, and finally apply 0.25 V (vs. SCE) to collect the ring-disk current data. After obtaining the ring-disk current data, calculate the number of transferred electrons and the hydrogen peroxide selectivity of this example according to the formula.

[0051] Example 6:

[0052] In this example, the synthesis method of oxygen-rich carbon quantum dots and their application in electrocatalytic hydrogen peroxide production include the following steps:

[0053] Dissolve 0.5 g of phloroglucinol in a mixed solvent of N,N-dimethylformamide and acetonitrile with a ratio of 1:1 and disperse it evenly by ultrasonic treatment. Then transfer the solution to a 100-mL polytetrafluoroethylene high-temperature and high-pressure autoclave and heat-treat it at 180 °C for 10 h. After the reaction solution is cooled to room temperature, use a 0.22-μm organic filter membrane to filter by suction with water and ethanol to obtain the filtrate, and dry the filtrate at 60 °C at room temperature to obtain carbon quantum dot powder. Grind the obtained powdery carbon quantum dots evenly, keep them warm in flowing N2 at 350 °C for 4 hours, with a heating rate of 5 °C / min. After the reaction is completed, wait for the temperature to drop to room temperature, take out the sample and grind it into a powdery state.

[0054] Take 1 mg of the carbon quantum dot powder material prepared in the above steps and dissolve it in 200 μL of water and 800 μL of isopropyl alcohol solution. Add 50 μL of the binder Nafion solution and ultrasonically disperse it until uniform. Take 5 μL and drop-coat it on the surface of a rotating ring-disk electrode of 0.19625 cm 2 and let it dry naturally. Ventilate for 1 h to saturate the electrolyte with oxygen. Use a three-electrode system to test and analyze the two-electron oxygen reduction performance of the carbon quantum dot catalyst prepared in this example. First, perform 20 cycles of cyclic voltammetry tests at a scan rate of 50 mV / s, with the scanning range from -0.2 to 0.8 V (vs. SCE). After the test, turn on the rotation control switch, set the rotation speed to 1600 rpm, apply a potential of -0.4 V (vs. SCE) to the ring electrode, and finally apply 0.25 V (vs. SCE) to collect the ring-disk current data. After obtaining the ring-disk current data, calculate the number of transferred electrons and the hydrogen peroxide selectivity of this example according to the formula.

[0055] The characterization results of the samples prepared in the above examples are as follows:

[0056] Using transmission electron microscopy, the average diameter of the carbon quantum dot catalyst synthesized in Example 4 is 2.34 nm, as shown in Attachment Figure 1 . Fourier transform infrared spectroscopy shows the strength of the surface functional groups of the carbon quantum dots obtained in Example 4, as shown in Attachment Figure 2 . X-ray photoelectron spectroscopy characterizes the oxygen content on the surface of the carbon quantum dots obtained in Example 4, as shown in Attachment Figure 3 . The hydrogen peroxide selectivity and number of transferred electrons diagram of the carbon quantum dot catalyst that electrochemically reduces oxygen to hydrogen peroxide prepared in Example 4, as shown in Attachment Figure 4 , which uses a one-step solvothermal method to prepare an oxygen-rich carbon quantum dot electrocatalytic material by regulating the polarity of the solvent using phloroglucinol, and uses an electrochemical method to efficiently reduce oxygen to hydrogen peroxide. The hydrogen peroxide selectivity diagram of the oxygen-rich carbon quantum dot catalysts prepared by calcination or without calcination in Examples 1 and 2, as shown in Attachment Figure 5 . The hydrogen peroxide selectivity diagram of the oxygen-rich carbon quantum dot catalysts prepared with or without adding a catalyst in Examples 2 and 3, as shown in Attachment Figure 6 .

[0057] In summary, by comparing Examples 1-6, it is found that the oxygen-rich carbon quantum dot catalyst prepared by the solvent engineering strategy of the present invention shows high selectivity for hydrogen peroxide in electrocatalysis without adding other catalysts and through a calcination preparation process.

[0058] Examples 7-12:

[0059] Compared with Example 4, most of them are the same, except that resorcinol is respectively changed to phenol, catechol, hydroquinone, phloroglucinol, 1,2,3-benzenetriol, and 1,2,4-benzenetriol with equal mass.

[0060] Examples 13 - 19:

[0061] Compared with Example 4, most of them are the same, except that the mixed solvent of ethanol and acetone is respectively replaced with water, ethanol, N,N-dimethylformamide, acetone, acetonitrile, formamide, or toluene with equal volume.

[0062] Examples 20 - 23:

[0063] Compared with Example 2, most of them are the same, except that the catalyst is respectively replaced with boric acid, citric acid, hydrazine hydrate, or sodium hydroxide with equal mass.

[0064] Example 24:

[0065] Compared with Example 2, most of them are the same, except that the reaction process parameters are adjusted as follows: the temperature of the solvothermal reaction is 130 °C and the time is 12 h; the temperature of the calcination is 250 °C and the time is 5 h.

[0066] Example 25:

[0067] Compared with Example 2, most of them are the same, except that the reaction process parameters are adjusted as follows: the temperature of the solvothermal reaction is 210 °C and the time is 10 h; the temperature of the calcination is 300 °C and the time is 3 h.

[0068] Example 26:

[0069] Compared with Example 2, most of them are the same, except that the reaction process parameters are adjusted as follows: the concentration of the phenolic compound in the phenolic precursor solution is 2 mg / mL.

[0070] Example 27:

[0071] Compared with Example 2, most of them are the same, except that the reaction process parameters are adjusted as follows: the concentration of the phenolic compound in the phenolic precursor solution is 20 mg / mL.

[0072] In summary, the synthesis method of the oxygen-rich carbon quantum dots in the above embodiments belongs to the field of electrocatalytic materials. In the above embodiments, phloroglucinol is selected as the precursor, and oxygen-rich carbon quantum dots with high selectivity and stability for oxygen reduction catalysis are synthesized by a solvothermal method and applied to electrocatalytic hydrogen peroxide production. The above embodiments do not use toxic reagents, and the raw material cost is low, providing a strong theoretical basis for the synthesis of efficient and stable carbon quantum dot catalysts and an effective solution for the preparation of catalysts for efficiently catalyzing the production of hydrogen peroxide from oxygen. The oxygen-rich carbon quantum dots prepared by the present invention are green, economical, environmentally friendly, and have excellent catalytic performance, with high selectivity for the two-electron oxygen reduction reaction, and the content of oxygen-containing functional groups plays a key role in the electrochemical catalytic process.

[0073] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A preparation method of oxygen-rich carbon quantum dots, characterized in that, It includes the following steps: (1) Take a phenolic compound and disperse it in a solvent to obtain a phenolic precursor solution; (2) Transfer the phenolic precursor solution to a reaction kettle for solvothermal reaction. After the obtained reaction product is filtered, dried, and ground, a crude product of carbon quantum dot powder is obtained; (3) After the crude product of carbon quantum dot powder is sufficiently ground, it is calcined under the protection of an inert gas to obtain the target product, oxygen-rich carbon quantum dots; In step (1), the phenolic compound is selected from at least one of phenol, catechol, resorcinol, hydroquinone, phloroglucinol, 1,2,3-benzenetriol, and 1,2,4-benzenetriol; In step (1), the solvent is one or a combination of several of water, ethanol, N,N-dimethylformamide, acetone, acetonitrile, formamide, or toluene; In step (2), the temperature of the solvothermal reaction is 130 - 210 °C; In step (3), the temperature of the calcination is 250 - 350 °C.

2. The preparation method of an oxygen-rich carbon quantum dot according to claim 1, characterized in that, In step (1), the concentration of the phenolic compound in the phenolic precursor solution is 2 - 20 mg / mL.

3. The preparation method of an oxygen-rich carbon quantum dot according to claim 1, characterized in that, In step (2), the time of the solvothermal reaction is 6 - 12 h.

4. The preparation method of an oxygen-rich carbon quantum dot according to claim 1, characterized in that, In step (3), the time of the calcination is 3 - 5 h.

5. An oxygen-rich carbon quantum dot prepared by the preparation method according to any one of claims 1 - 4.

6. Use of the oxygen-rich carbon quantum dot according to claim 5 in electrocatalytic production of hydrogen peroxide.

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