A sp 2 / sp 3 Carbon hybridized two-dimensional nanodiamond electrocatalyst and its preparation method and application

Abstract

The present invention discloses a sp<supgt;2< / supgt; / sp<supgt;3< / supgt; carbon hybridized two-dimensional nanodiamond electrocatalyst, its preparation method and application. The preparation method is to wash the two-dimensional nanodiamond with alcohol, filter and dry it to initially wash away the impurities in the material. Then, the obtained product is treated in an acid solution to further remove the difficult-to-treat impurities, washed and dried. Finally, the obtained product is placed in a tube furnace and calcined at high temperature in an inert atmosphere. After natural cooling to room temperature, the sp<supgt;2< / supgt> / sp<supgt;3< / supgt> carbon hybridized two-dimensional nanodiamond electrocatalyst can be obtained. By controlling the calcination temperature, the precise control of the sp<supgt;2< / supgt> / sp<supgt;3< / supgt> hybridization ratio can be achieved. Through structure regulation, the present invention prepares a hybrid two-dimensional nanodiamond with characteristics such as a wide potential window, low background current, and high stability, greatly improving the current efficiency of electrolyzing water to prepare ozone. Moreover, the preparation process of this electrocatalyst is simple and the cost is low.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterials and electrocatalysis technology, and in particular to a sp 2 / sp 3 Carbon hybridized two-dimensional nanodiamond electrocatalysts and their preparation methods and applications. Background Art

[0002] As an environmentally friendly strong oxidant, ozone can quickly and thoroughly eliminate viruses and bacteria in the air and water, so it is widely used in sterilization, deodorization and decolorization. In terms of sterilization and disinfection, compared with traditional chlorine-containing disinfectants, ozone is reduced to oxygen during the disinfection process, which is safe, efficient and has no secondary pollution. Various substances harmful to the human body in life (such as carbon monoxide, pesticides, heavy metals, fertilizers, organic matter, odor, pigments, etc.) will be decomposed into safe substances that are harmless to the human body after ozone treatment. The United States, Japan and advanced European and American countries have already applied ozone to the storage of various foods. It can extend the storage period of food and reduce the spoilage rate to reduce losses and increase profits. Because ozone has a strong oxidizing effect, it is itself a strong bleaching agent and can be used in laundry, food, and wastewater treatment. In addition, according to different application industries and places, the main applications of ozone can be summarized as: medical care, food processing industry, livestock and poultry farming, water treatment, etc.

[0003] At present, there are three main ways to prepare ozone: dielectric barrier discharge, ultraviolet radiation, and electrolysis. The commonly used method for preparing ozone in industry is dielectric barrier discharge, also known as corona discharge, which is an AC high-pressure, low-temperature non-equilibrium gas discharge process. Its production equipment is large and the cost is high. In addition, due to high-voltage ionization, there are nitrogen oxides (NO x) are toxic and harmful. The ultraviolet irradiation method is actually a method of imitating the production of ozone in the atmosphere, artificially generating an ultraviolet spectrum with a wavelength of 185nm to irradiate the oxygen in the air, but the radiation hazard of this process is the main limiting factor, and the ozone production is small, the production equipment is complex, and the wavelength is difficult to control. Compared with the first two ozone production methods, the electrolysis method has the following advantages: (1) It is easy to operate and can produce high-concentration ozone in a green and efficient manner; (2) It uses pure water as raw material and does not require processing, which is green and environmentally friendly and has no secondary pollution; (3) The equipment is simple, easy to carry and can be used in various situations. In the process of preparing ozone by electrolysis, ozone and oxygen are produced at the anode, and hydrogen is produced at the cathode. Selecting an anode material with a high overpotential can effectively inhibit the production of oxygen and improve the current efficiency of ozone production. At present, the electrolysis of water to prepare ozone mainly uses lead dioxide as an anode catalyst, but it is well known that lead is a toxic substance. Large-scale application will lead to the generation of a large amount of toxic industrial waste residue. Therefore, it is of great significance to design a lead-free system anode catalyst to replace the lead-containing anode catalyst for the electrolysis of water to prepare ozone. As a new type of carbon material, two-dimensional nanodiamond has attracted increasing attention in the field of electrocatalysis due to its excellent chemical stability, easy surface modification, and large specific surface area. However, no one has reported on the use of two-dimensional nanodiamond to produce ozone by electrolysis. Summary of the invention

[0004] In view of the above problems existing in the prior art, the object of the present invention is to provide a sp 2 / sp 3 A two-dimensional nanodiamond electrocatalyst with a carbon hybrid ratio, a preparation method and an application thereof. The catalyst prepared by the present invention has low cost and a simple preparation process, and has a high reaction efficiency when used for electrocatalytic reaction to prepare ozone. In addition, the hybrid two-dimensional nanodiamond electrocatalyst has mild operating conditions for the electrocatalytic reaction process, can produce high-concentration ozone, is green and efficient, and has no secondary pollution.

[0005] A sp 2 / sp 3 The method for preparing a carbon-hybridized two-dimensional nanodiamond electrocatalyst comprises the following steps:

[0006] 1) dispersing the two-dimensional nanodiamond in an ethanol solution and ultrasonically treating it for 20-60 minutes, and then washing and filtering the resulting black suspension with ultrapure water;

[0007] 2) dispersing the preliminarily washed two-dimensional nanodiamond obtained in step 1) in an inorganic acid solution, heat-treating in an oil bath at 40-80° C., then washing the obtained product with anhydrous ethanol and deionized water for 3-5 times each, and vacuum drying at 50-80° C. for 8-18 hours to obtain a pure two-dimensional nanodiamond material;

[0008] 3) The pure two-dimensional nanodiamond material obtained in step 2) is transferred to a porcelain boat and placed in a tube furnace. The temperature is gradually increased under an inert gas atmosphere. After the temperature reaches a certain temperature, the material is calcined at a constant temperature for 2-8 hours. After the material is naturally cooled to room temperature, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts.

[0009] Furthermore, the mass concentration of the ethanol solution in step 1) is 70%-95%, the ultrasonic time is 0.5-1 hour, the volume ratio of the mass of the two-dimensional nanodiamond to the ethanol solution is 1:20-30, the mass unit is g, and the volume unit is mL.

[0010] Furthermore, the inorganic acid in step 2) is sulfuric acid or nitric acid, the concentration is 3-5 mol / L, and the heat treatment time is 6-12 hours.

[0011] Furthermore, the inert gas in step 3) is argon, helium or nitrogen, the calcination temperature is 600-1400°C, the gradual heating rate is 5-10°C / min, the gas flow rate of the inert gas is 50-100mL / min, and the calcination time is 3-6 hours.

[0012] A sp prepared by the above preparation method 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts with coplanar sp 2 Carbon and sp 3 carbon.

[0013] A sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts can be controlled by calcining at different temperatures 2 and sp 3 The hybridization ratio of carbon can further regulate the structure of two-dimensional nanodiamonds. 2 / sp 3 The hybridization ratio of carbon is controlled at 0.5-1.2.

[0014] One of the above sp 2 / sp 3 The application of carbon hybridized two-dimensional nanodiamond electrocatalyst in the preparation of ozone by electrolysis of water comprises the following steps: controlling the voltage and current by a constant current instrument, using an H-type electrolytic cell to perform an ozone preparation reaction by electrolysis of water, maintaining the flow of water and gas between the anode electrolysis chamber and the cathode electrolysis chamber of the H-type electrolytic cell, using a saturated potassium sulfate aqueous solution as an electrolyte, and2 / sp 3 The carbon-hybridized two-dimensional nanodiamond electrocatalyst was coated on carbon cloth as the working electrode in the anode chamber, and a platinum sheet was used as the counter electrode in the cathode chamber. The reaction current was controlled at 75 mA / cm 2 The cell voltage of the H-type electrolytic cell is controlled between 4-10V, and then water is electrolyzed to prepare ozone to obtain ozone products.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) The present invention prepares a novel and efficient hybrid two-dimensional nanodiamond material through structural optimization, which has high electrocatalytic ozone production activity and great application value. At the same time, by adjusting the calcination temperature, sp 2 / sp 3 The hybridization ratio is changed to obtain electrocatalysts with different electrocatalytic properties.

[0017] 2) The sp 2 -C and sp 3 -C are in the same plane, and sp 2 -C ratio is significantly increased. Compared with the untreated two-dimensional nanodiamond, the hybrid two-dimensional nanodiamond utilizes the interaction between different carbon electrons to significantly improve the catalytic activity and stability of the electrolysis of water to prepare ozone, providing basic application research for this type of material in the field of electrocatalysis and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the prior art solutions, the drawings required for describing the embodiments or the prior art are briefly introduced below.

[0019] Figure 1a The sp prepared in Example 1 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm;

[0020] Figure 1b A transmission electron microscope schematic diagram of the sp2 / sp3 carbon hybridized two-dimensional nanodiamond electrocatalyst prepared in Example 1 at 10 nm;

[0021] Figure 2a The sp prepared in Example 2 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm;

[0022] Figure 2b The sp prepared in Example 22 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 10 nm;

[0023] Figure 3a The sp prepared in Example 3 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm;

[0024] Figure 3b The sp prepared in Example 3 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 10 nm;

[0025] Figure 4a The sp prepared in Example 4 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm;

[0026] Figure 4b The sp prepared in Example 4 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 10 nm;

[0027] Figure 5a The sp prepared in Example 5 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm;

[0028] Figure 5b The sp prepared in Example 5 2 / sp 3 Schematic diagram of transmission electron microscopy of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 10 nm;

[0029] Figure 6 sp prepared in Example 1-5 2 / sp 3 X-ray photoelectron spectra of carbon-hybridized two-dimensional nanodiamond electrocatalysts and the corresponding sp 2 / sp 3 Changes in the proportion of carbon;

[0030] Figure 7 sp prepared in Example 1-5 2 / sp 3Real-time data comparison of ozone concentration produced when carbon-hybridized two-dimensional nanodiamond electrocatalyst and unhybridized two-dimensional nanodiamond are used to electrolyze water to produce ozone. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and the protection scope of the present invention is not limited thereto.

[0032] Example 1: A sp 2 / sp 3 The preparation of carbon hybridized two-dimensional nanodiamond electrocatalyst comprises the following steps:

[0033] 1) Disperse 1.0 g of two-dimensional nanodiamond in 20 mL of 95% ethanol solution and ultrasonically treat for 30 min, then wash and filter the resulting black suspension with ultrapure water;

[0034] 2) dispersing the two-dimensional nanodiamond obtained in step 1) after preliminary washing in 20 mL of 3 mol / L nitric acid solution, heat-treating in an oil bath at 40° C. for 12 h, then washing the obtained product with anhydrous ethanol and deionized water three times each, and vacuum drying at 50° C. for 18 hours to obtain a pure two-dimensional nanodiamond material;

[0035] 3) The pure two-dimensional nanodiamond obtained in step 2) is transferred to a porcelain boat and placed in a tube furnace, and calcined at a high temperature of 5°C / min under argon gas, the calcination temperature is 600°C, the gas flow rate is 100 mL / min, and the calcination time is 6 hours. After it is naturally cooled to room temperature, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts.

[0036] The sp obtained in Example 1 2 / sp 3 Schematic diagram of transmission electron microscopy of hybrid two-dimensional nanodiamond electrocatalyst at 50nm and 10nm. Figure 1a and 1b As shown in the figure, it can be seen that there is a clear difference in lattice fringes between the edge and the interior, which is due to the sp 2 Hybridization, and Figure 6 As shown, through XPS analysis, different implementation cases can obtain different sp 2 / sp 3 Hybridization ratio, sp 2 / sp 3The hybridization ratio reaches 0.51. The unique hybridization ratio is conducive to the adsorption and desorption of intermediates in the ozone generation process, making ozone easier to generate.

[0037] The sp prepared in Example 1 2 / sp 3 The catalytic performance of carbon-hybridized two-dimensional nanodiamond electrocatalysts was tested:

[0038] Weigh 8 mg of the prepared sp 2 / sp 3 Carbon hybridized two-dimensional nanodiamond electrocatalyst powder was mixed with 1000 μL of anhydrous ethanol and 200 μL of Nafion solution (the mass concentration of Nafion solution was 5%), and ultrasonic treatment was performed for 30 minutes to make the catalyst completely dispersed in the mixture of anhydrous ethanol and Nafion solution to obtain a uniform catalyst slurry. The carbon cloth was cut into a size of about 2 cm × 2 cm, and the catalyst slurry was evenly dripped on the carbon cloth. After drying, it was used as a working electrode.

[0039] The current and voltage of the reaction were controlled by a constant current instrument. An H-type electrolytic cell was used as the reaction container. In the anode chamber, the sp 2 / sp 3 The carbon-hybridized two-dimensional nanodiamond electrocatalyst is coated on carbon cloth as the working electrode; the platinum sheet is used as the counter electrode in the cathode chamber, and the electrolyte is a saturated potassium sulfate solution. The amount of ozone generated is detected in real time by an American 2B ozone detector to reflect the electrocatalyst's performance in producing ozone by electrolyzing water. In the entire electrochemical reaction, the reaction current is controlled at 75mA / cm 2 The cell voltage range is 4-10V, and the reaction time is 90min. As the reaction proceeds, the ozone concentration will change significantly. Figure 7 It can be seen that after 90 minutes of reaction, the ozone concentration can reach 1596 ppb.

[0040] Example 2: A sp 2 / sp 3 The preparation of carbon-hybridized two-dimensional nanodiamond electrocatalysts is as follows:

[0041] 1) Disperse 1.0 g of two-dimensional nanodiamond in 25 mL of 75% ethanol solution and ultrasonically treat for 40 min, then wash and filter the resulting black suspension with ultrapure water;

[0042] 2) dispersing the preliminarily washed two-dimensional nanodiamond obtained in step 1) in 25 mL of a 4 mol / L sulfuric acid solution, heat-treating the product in an oil bath at 50° C. for 8 h, then washing the product with anhydrous ethanol and deionized water 5 times each, and vacuum drying the product at 60° C. for 16 hours to obtain a pure two-dimensional nanodiamond material;

[0043] 3) The pure two-dimensional nanodiamond obtained in step 2) is transferred to a porcelain boat and placed in a tubular furnace, and calcined at a high temperature of 800°C, a gas flow rate of 90 mL / min, and a calcination time of 5 hours under helium. After it is naturally cooled to room temperature, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts.

[0044] The sp obtained in Example 2 2 / sp 3 Schematic diagram of transmission electron microscopy of hybrid two-dimensional nanodiamond electrocatalyst at 50nm and 10nm. Figure 2a and 2b As shown in the figure, it can be seen that there is a clear difference in lattice fringes between the edge and the interior, which is due to the sp 2 Hybridization, and Figure 6 As shown, by XPS analysis, the sp 2 / sp 3 The hybridization ratio reached 0.67.

[0045] The sp prepared in Example 2 2 / sp 3 The catalytic performance of the carbon-hybridized two-dimensional nanodiamond electrocatalyst was tested as follows:

[0046] In the process of preparing the electrode anode using the catalyst prepared in Example 1, the added catalyst in Example 1 was replaced with the catalyst prepared in Example 2 of equal mass, and the other operating conditions were the same as the experimental process of preparing ozone by electrolysis of water in Example 1. The relationship between the concentration of ozone generated by the electrolysis of water catalysis and the reaction time is as follows: Figure 7 As shown in the figure, it can be seen that after 90 minutes, the concentration of gaseous ozone produced reached 2310ppb. 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalyst has a good ozone production performance.

[0047] Example 3: A sp 2 / sp 3 The preparation of carbon-hybridized two-dimensional nanodiamond electrocatalysts is as follows:

[0048] 1) Disperse 1.0 g of two-dimensional nanodiamond in 30 mL of 95% ethanol solution and ultrasonically treat for 50 min, then wash and filter the resulting black suspension with ultrapure water;

[0049] 2) dispersing the two-dimensional nanodiamond obtained in step 1) after preliminary washing in 30 mL of 5 mol / L nitric acid solution, heat-treating in an oil bath at 60° C. for 6 h, then washing the obtained product with anhydrous ethanol and deionized water three times each, and vacuum drying at 70° C. for 14 hours to obtain a pure two-dimensional nanodiamond material;

[0050] 3) The pure two-dimensional nanodiamond obtained in step 2) is transferred to a porcelain boat and placed in a tubular furnace, and calcined at a high temperature of 7°C / min under nitrogen, the calcination temperature is 1000°C, the gas flow rate is 80 mL / min, the calcination time is 6 hours, and after it is naturally cooled to room temperature, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts.

[0051] Example 3 obtained sp 2 / sp 3 Transmission electron microscopy diagram of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm and 10nm. Figure 3a and 3b As shown in the figure, it can be seen that there is a clear difference in lattice fringes between the edge and the interior, which is due to the sp 2 hybridization; and Figure 6 As shown, by XPS analysis, the sp 2 / sp 3 The hybridization ratio reached 0.79.

[0052] The catalytic performance of the carbon-hybridized two-dimensional nanodiamond electrocatalyst prepared in Example 3 was tested, and the specific method was as follows:

[0053] In the process of preparing the electrode anode using the catalyst prepared in Example 1, the catalyst in Example 1 was replaced with the catalyst prepared in Example 3 of the same mass. The remaining operating conditions were the same as those in the experimental process of preparing ozone by electrolysis of water in Example 1. The relationship between the concentration of ozone generated by the electrolysis of water catalysis and the reaction time is as follows: Figure 7 As shown in the figure, it can be seen that after 90 minutes, the concentration of gaseous ozone produced reached 3085ppb. 2 / sp 3 Hybrid two-dimensional nanodiamond electrocatalyst has a good ozone production performance.

[0054] Example 4: A sp 2 / sp 3 The preparation of carbon-hybridized two-dimensional nanodiamond electrocatalysts is as follows:

[0055] 1) Dispersing 1.0 g of two-dimensional nanodiamond in 25 mL of 95% ethanol solution and ultrasonically treating for 60 min, then washing and filtering the resulting black suspension with ultrapure water;

[0056] 2) dispersing the preliminarily washed two-dimensional nanodiamond obtained in step 1) in 25 mL of 4 mol / L nitric acid solution, heat-treating in an oil bath at 60° C. for 8 h, then washing the obtained product with anhydrous ethanol and deionized water 5 times each, and vacuum drying at 80° C. for 12 hours to obtain a pure two-dimensional nanodiamond material;

[0057] 3) The pure two-dimensional nanodiamond obtained in step 2) is transferred to a porcelain boat and placed in a tube furnace, and calcined at a high temperature of 8°C / min under argon gas, the calcination temperature is 1200°C, the gas flow rate is 70 mL / min, the calcination time is 8 hours, and after it is naturally cooled to room temperature, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts.

[0058] Example 4 obtained sp 2 / sp 3 Transmission electron microscopy diagram of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm and 10nm. Figure 4a and 4b As shown in the figure, it can be seen that there is a clear difference in lattice fringes between the edge and the interior, which is due to the sp 2 hybridization; and Figure 6 As shown, by XPS analysis, the sp 2 / sp 3 The hybridization ratio reached 0.82.

[0059] The catalytic performance of the carbon-hybridized two-dimensional nanodiamond electrocatalyst prepared in Example 4 was tested, and the specific method was as follows:

[0060] In the process of preparing the electrode anode using the catalyst prepared in Example 1, the catalyst in Example 1 was replaced with the catalyst prepared in Example 4 of the same mass. The remaining operating conditions were the same as those in the experimental process of preparing ozone by electrolysis of water in Example 1. The relationship between the concentration of ozone generated by the electrolysis of water catalysis and the reaction time was as follows: Figure 7As shown in the figure, it can be seen that after 90 minutes, the concentration of gaseous ozone produced reached 2507ppb. 2 / sp 3 Hybrid two-dimensional nanodiamond electrocatalyst has a good ozone production performance.

[0061] Example 5: A method for preparing hybrid two-dimensional nanodiamond, the specific steps are as follows:

[0062] 1) Dispersing 1.0 g of two-dimensional nanodiamond in 30 mL of 75% ethanol solution and ultrasonically treating for 60 min, then washing and filtering the resulting black suspension with ultrapure water;

[0063] 2) dispersing the two-dimensional nanodiamond obtained in step 1) after preliminary washing in 30 mL of 5 mol / L sulfuric acid solution, heat-treating in an oil bath at 50° C. for 10 h, then washing the obtained product with anhydrous ethanol and deionized water three times each, and vacuum drying at 60° C. for 16 hours to obtain a pure two-dimensional nanodiamond material;

[0064] 3) The pure two-dimensional nanodiamond obtained in step 2) is transferred to a porcelain boat and placed in a tubular furnace, and calcined at a high temperature of 10°C / min under helium, the calcination temperature is 1400°C, the gas flow rate is 50mL / min, the calcination time is 6 hours, and after it is naturally cooled to room temperature, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts.

[0065] Example 5 sp 2 / sp 3 Transmission electron microscopy diagram of carbon-hybridized two-dimensional nanodiamond electrocatalyst at 50nm and 10nm. Figure 5a and 5b As shown in the figure, it can be seen that there is a clear difference in lattice fringes between the edge and the interior, which is due to the sp 2 hybridization; and Figure 6 As shown, by XPS analysis, the sp 2 / sp 3 The hybridization ratio reached 1.10.

[0066] The catalytic performance of the hybrid two-dimensional nanodiamond electrocatalyst prepared in Example 5 was tested, and the specific method was as follows:

[0067] In the process of preparing the electrode anode using the catalyst prepared in Example 1, the catalyst in Example 1 was replaced with the catalyst prepared in Example 5 of the same mass. The remaining operating conditions were the same as the experimental process of preparing ozone by electrolysis of water in Example 1. The relationship between the concentration of ozone generated by the electrolysis of water catalysis and the reaction time is as follows: Figure 7 As shown in the figure, it can be seen that after 90 minutes, the concentration of gaseous ozone produced reached 2402ppb. 2 / sp 3 Hybrid two-dimensional nanodiamond electrocatalyst has a good ozone production performance.

[0068] The control group example refers to the direct use of two-dimensional nanodiamond as a water electrolysis electrocatalyst to test the catalytic performance of ozone generation by water electrolysis. The specific method is as follows:

[0069] Weigh 8 mg of two-dimensional nanodiamond electrocatalyst particles, mix with 1000 μL of ethanol and 200 μL of Nafion solution (Nafion solution mass concentration is 5%), and ultrasonicate for 30 minutes to completely disperse the catalyst in the mixture of ethanol and Nafion solution to obtain a uniform catalyst slurry. Cut the carbon cloth into a size of about 2 cm × 2 cm, and evenly drip the dispersed catalyst slurry on the carbon cloth, and use it as a working electrode after drying (i.e., the hybrid two-dimensional nanodiamond electrocatalyst is coated on the carbon cloth as a working electrode).

[0070] The voltage and current are controlled by a constant current meter, and an H-type electrolytic cell is used for the reaction. In the anode chamber, the hybrid two-dimensional nanodiamond electrocatalyst is coated on a carbon cloth as a working electrode; in the cathode chamber, a platinum sheet is used as a counter electrode, and the electrolyte is a saturated potassium sulfate aqueous solution. An ozone detector is connected to one end of the H-type electrolytic cell to detect the generation of ozone in real time. During the electrocatalytic ozone production reaction, the current is controlled at 75mA / cm 2 , reaction time 1.5 hours. As the reaction proceeds, the real-time detection diagram of the ozone concentration produced by the electrocatalytic reaction is as follows Figure 7 As shown. Figure 7 It can be seen from the above that as the reaction proceeds, the ozone concentration gradually increases. When the reaction time reaches nearly 90 minutes, the ozone concentration can reach 1070 ppb.

[0071] from Figure 7 It can be seen that when applied to the electrocatalytic preparation of ozone reaction, the catalytic reaction rate and catalytic effect of the hybrid two-dimensional nanodiamond electrocatalyst prepared by the present invention are improved compared with two-dimensional nanodiamond.

[0072] The contents described in this specification are merely an enumeration of implementation forms of the inventive concept, and the protection scope of the present invention should not be considered as being limited to the specific forms described.

Claims

1. A sp 2 / sp 3 A method for preparing a carbon-hybridized two-dimensional nanodiamond electrocatalyst, characterized in that The following steps are involved: 1) Dispersing the two-dimensional nanodiamond in an ethanol solution and ultrasonically treating it for 20-60 minutes, then washing and filtering the resulting black suspension with ultrapure water; 2) dispersing the preliminarily washed two-dimensional nanodiamond obtained in step 1) in an inorganic acid solution, heat-treating in an oil bath at 40-80° C., then washing the obtained product with anhydrous ethanol and deionized water for 3-5 times each, and vacuum drying at 50-80° C. for 8-18 hours to obtain a pure two-dimensional nanodiamond material; 3) The pure two-dimensional nanodiamond material obtained in step 2) is transferred to a porcelain boat and placed in a tube furnace. The temperature is gradually increased under an inert gas atmosphere. After the temperature is increased to 600-1400°C, constant temperature calcination is performed for 2-8 hours. After the material is naturally cooled to room temperature, sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts.

2. The preparation method according to claim 1, characterized in that The mass concentration of the ethanol solution in step 1) is 70%-95%, the ultrasonic time is 0.5-1 hour, the volume ratio of the mass of the two-dimensional nanodiamond to the ethanol solution is 1:20-30, the mass unit is g, and the volume unit is mL.

3. The preparation method according to claim 1, characterized in that The inorganic acid in step 2) is sulfuric acid or nitric acid, the concentration is 3-5 mol / L, and the heat treatment time is 6-12 hours.

4. The preparation method according to claim 1, characterized in that The inert gas described in step 3) is argon, helium or nitrogen, the heating rate of the gradual heating is 5-10°C / min, the gas flow rate of the inert gas is 50-100 mL / min, and the calcination time is 3-6 hours.

5. A sp prepared by the preparation method according to any one of claims 1 to 4 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalyst, characterized by sp 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalysts with coplanar sp 2 Carbon and sp 3 carbon.

6. The sp as claimed in claim 5 2 / sp 3 Carbon-hybridized two-dimensional nanodiamond electrocatalyst, characterized by sp 2 / sp 3 The hybridization ratio is 0.5-1.

2.

7. A sp as claimed in claim 6 2 / sp 3 Application of carbon-hybridized two-dimensional nanodiamond electrocatalysts in ozone production by water electrolysis.

8. The use according to claim 7, characterized in that The following steps are involved: The voltage and current are controlled by a constant current meter, and an H-type electrolytic cell is used to electrolyze water to prepare ozone. Water and gas flow between the anode electrolysis chamber and the cathode electrolysis chamber of the H-type electrolytic cell is maintained. A saturated potassium sulfate aqueous solution is used as the electrolyte. 2 / sp 3 The carbon-hybridized two-dimensional nanodiamond electrocatalyst was coated on carbon cloth as the working electrode in the anode chamber, and a platinum sheet was used as the counter electrode in the cathode chamber. The reaction current was controlled at 75 mA / cm 2 The cell voltage of the H-type electrolytic cell is controlled between 4-10 V, and then water is electrolyzed to prepare ozone to obtain ozone products.

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