Amorphous carbon oxynitride boride material and preparation method and application thereof

Abstract

The application discloses an amorphous boron-oxygen-nitrogen-carbon material and a preparation method and application thereof, and belongs to the field of photocatalysis. The amorphous boron-oxygen-nitrogen-carbon material contains 1-10 wt% of boron, 2-20 wt% of oxygen, and the rest is a carbon-nitrogen structure composed of a carbon-nitrogenazine ring. The application complexes boron-oxygen chemical bonds on melamine, introduces boron-oxygen structures into the carbon-nitrogenazine ring structure through secondary calcination, utilizes boron atoms and oxygen atoms to destroy and recombine the crystal structure of carbon nitride, and forms an amorphous boron-oxygen-nitrogen-carbon material based on theazine ring structure. The size and catalytic activity of the material are regulated by adjusting the component proportion of the boron-oxygen structure and the carbon-nitrogenazine ring, so that the prepared material is suitable for efficient photocatalytic synthesis of H2O2 in an oxygen-deficient environment. In the preparation method, a dehydration complexation reaction is utilized before calcination treatment, a complex precursor is formed, the boron-oxygen content in the boron-oxygen-nitrogen-carbon material is more controllable, and the amorphous characteristics of the material are more prominent.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis, specifically to an amorphous boron oxynitride carbon material, its preparation method, and its applications. Background Technology

[0002] Since the beginning of the 21st century, rapid technological advancements and global industrialization have led to a continuous expansion of applications and increasing demand for hydrogen peroxide. Photocatalysis, using sunlight as a driving force and water as a raw material, is an effective means of achieving green and sustainable hydrogen peroxide synthesis. Compared to other methods, photocatalytic synthesis of hydrogen peroxide offers advantages such as high yield, high safety, simple equipment, and no pollution, making it suitable for industrial-scale synthesis. Developing photocatalysts that can efficiently convert water into hydrogen peroxide under sunlight is crucial for advancing photocatalytic synthesis technology for hydrogen peroxide.

[0003] In existing research, carbon nitride-based photocatalysts are among the materials with the highest hydrogen peroxide yield, and their preparation process is simple, their structure is stable, and they exhibit high selectivity for the hydrogen peroxide synthesis reaction. However, traditional carbon nitride-based photocatalysts are highly dependent on dissolved oxygen concentration when synthesizing hydrogen peroxide, and they cannot efficiently synthesize hydrogen peroxide from pure water with low oxygen content, which limits their application in industrial production.

[0004] Therefore, how to provide an effective method to improve the photocatalytic synthesis of hydrogen peroxide by carbon nitride-based photocatalysts under low dissolved oxygen concentrations is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] Purpose of the invention: The present invention aims to provide an amorphous boron oxynitride carbon material with high catalytic activity and high stability, which can be applied to the efficient photocatalytic synthesis of hydrogen peroxide from pure water under low dissolved oxygen concentration. Furthermore, the present invention also provides a method for preparing the amorphous boron oxynitride carbon material and its application.

[0006] Technical solution: The preparation method of amorphous boron oxynitride carbon material provided by the present invention includes the following steps:

[0007] (1) Add boric acid aqueous solution to melamine suspension, mix and carry out dehydration complexation reaction to obtain boron oxygen nitride carbon complex precursor, and then solidify it.

[0008] (2) The boron oxynitride carbon complex precursor after curing treatment is ground and then calcined twice. After the calcination is completed, it is ground again and then placed in an organic solution and centrifuged and dried to obtain amorphous boron oxynitride carbon material.

[0009] Further, in step (1), the concentration of the boric acid aqueous solution is 0.125-2.5 mmol / mL; the molar ratio of melamine in the melamine suspension to boric acid in the boric acid aqueous solution is 1:0.05-1, preferably 1:0.5.

[0010] Further, in step (1), the boric acid aqueous solution is prepared by dissolving boric acid in water and keeping it at 88-97℃ for 5-30 minutes; the melamine suspension is prepared by dissolving melamine in water and keeping it at 88-97℃ for 5-30 minutes.

[0011] Further, in step (1), the conditions for the dehydration complexation reaction are: reaction at 88-97℃ for 5-30 min; the conditions for the curing treatment are: curing at 80-100℃ for 12-24 h.

[0012] Further, in step (2), the conditions for the first calcination in the secondary calcination process are: calcination temperature of 200-300℃, heating rate of 2-10℃ / min, argon flow rate of 100-250sccm during calcination, and holding time of 1-2 hours; the conditions for the second calcination in the secondary calcination process are: raising the calcination temperature from the temperature of the first calcination to 480-550℃, heating rate of 1-5℃ / min, argon flow rate of 100-300sccm during calcination, and holding time of 1-4 hours.

[0013] Further, in step (2), the organic solution is ethanol; the centrifugation speed is 6000-8000 r / min and the time is 1-3 min; the drying temperature is 60-80℃ and the time is 12-24 h.

[0014] The present invention also provides an amorphous boron oxynitride carbon material prepared by the above preparation method, wherein the boron content is 1-10 wt%, the oxygen content is 2-20 wt%, and the remainder is a carbon nitride structure composed of carbon aziridine rings.

[0015] This invention also provides the application of the above-mentioned amorphous boron oxynitride carbon material as a photocatalyst in the photocatalytic synthesis of H2O2.

[0016] Furthermore, the method for photocatalytic synthesis of H2O2 is as follows: under the condition of dissolved oxygen concentration of 2.6-16.4 mg / L, amorphous boron oxynitride carbon material is added to pure water as a photocatalyst, and the photocatalytic reaction is carried out under light irradiation.

[0017] Furthermore, the amount of the amorphous boron oxynitride carbon material added is 0.5-10 mg per 1 mL of pure water.

[0018] Invention Principle: At high temperatures, boric acid and melamine undergo dehydrogenation in an aqueous solution, resulting in a dehydration complexation reaction to form a melamine-boric acid complex. During high-temperature calcination, the melamine-boric acid complex undergoes a thermal polymerization reaction, where the internal melamine forms carbon nitride. Boron and oxygen atoms replace the carbon and nitrogen atoms in the zirconia ring of the carbon nitride, respectively, disrupting the long-range ordered structure of the carbon nitride and forming amorphous boron-oxygenated carbon nitride. The structure formed by boron and oxygen atoms results in a strong regional variation in the distribution of photogenerated charges in boron-oxygenated carbon nitride, which helps reduce the recombination of electrons and holes. Boron atoms enhance the oxidation capacity of photogenerated holes in boron-oxygenated carbon nitride, promoting the catalytic oxidation of water to obtain oxygen and hydrogen peroxide. Furthermore, the boron-oxygen structure formed by boron and oxygen atoms acts as an active site for the oxygen reduction reaction, effectively utilizing electrons to reduce dissolved oxygen and in-situ generated oxygen to obtain hydrogen peroxide. Simultaneously, singlet oxygen can be effectively generated and converted into hydrogen peroxide in boron-oxygenated carbon nitride.

[0019] This invention utilizes boron and oxygen atoms to regulate the crystallinity and physicochemical properties of carbon nitride, enabling the effective utilization of photogenerated holes in boron-oxygen-nitride to generate oxygen and highly reactive singlet oxygen in situ, thereby avoiding the recombination of photogenerated holes and electrons. Since the in-situ generated oxygen and singlet oxygen can be converted into hydrogen peroxide, the hydrogen peroxide synthesis performance of boron-oxygen-nitride is independent of dissolved oxygen concentration.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0021] (1) The performance of the amorphous boron oxynitride carbon material of the present invention in photocatalytic synthesis of hydrogen peroxide from pure water is improved by about 14 times that of carbon nitride.

[0022] (2) When the amorphous boron oxynitride carbon material of the present invention is used for photocatalytic synthesis of hydrogen peroxide, the yield of hydrogen peroxide does not depend on the dissolved oxygen concentration and can still reach 742 μM (1 hour) under low oxygen concentration.

[0023] (3) The amorphous boron oxynitride carbon material of the present invention has a stable structure. After continuous catalysis for 30 hours and recycling 5 times, the hydrogen peroxide yield still remains at about 80% of the initial reaction.

[0024] (4) The physicochemical properties of the amorphous boron oxynitride carbon material of the present invention can be flexibly controlled according to the content of boric acid in the precursor, and it is expected to be applied to other directions of photocatalysis and photoluminescence. Attached Figure Description

[0025] Figure 1Scanning electron microscope images of amorphous boron oxynitride carbon prepared in Examples 1(a) and 2(b), amorphous carbon nitride prepared in Comparative Example 1(c), and amorphous boron oxynitride carbon prepared in Comparative Example 3(d);

[0026] Figure 2 Transmission electron microscope images of amorphous boron oxynitride carbon prepared for Examples 1 (ab) and 2 (cd);

[0027] Figure 3 X-ray diffraction images of amorphous boron oxynitride prepared in Examples 1-4 and amorphous carbon nitride prepared in Comparative Example 1;

[0028] Figure 4 X-ray photoelectron spectra of amorphous borooxynitride carbon prepared in Examples 2 and 4;

[0029] Figure 5 Transient fluorescence spectra of amorphous borooxynitride and amorphous carbon nitride prepared in Example 2 and Comparative Example 1;

[0030] Figure 6 The graph shows the yield of hydrogen peroxide synthesized by photocatalysis from amorphous boron oxynitride prepared in Examples 1-4 and Comparative Example 3, amorphous carbon nitride prepared in Comparative Example 1, and boron-doped carbon nitride prepared in Comparative Example 2.

[0031] Figure 7 The graphs show the photocatalytic hydrogen peroxide production of amorphous boron oxynitride and amorphous carbon nitride prepared in Example 2 and Comparative Example 1 under different dissolved oxygen concentrations.

[0032] Figure 8 The stability test diagram shows the photocatalytic synthesis of hydrogen peroxide using amorphous boronoxynitride carbon prepared in Example 2. Detailed Implementation

[0033] The present invention will now be further described in conjunction with specific embodiments and accompanying drawings.

[0034] Example 1: The amorphous boron-oxygen-nitrogen photocatalyst provided in this example has a boron content of 1.7 wt%, an oxygen content of 2.4 wt%, and the remainder is a carbon nitride structure composed of carbon aziridine rings;

[0035] The preparation method includes the following steps:

[0036] (1) Weigh 65 mg of boric acid and 1.26 g of melamine respectively, and place them in beakers. Mix them with 3 mL and 4 mL of deionized water respectively at 92 °C, and keep warm for 15 minutes to obtain boric acid solution and melamine suspension.

[0037] (2) Pour the boric acid solution from step (1) into the melamine suspension, mix it with the solution, stir it, keep it warm, and carry out a dehydration complexation reaction for 15 minutes to obtain the complex precursor. Then, cure it at 80°C for 12 hours.

[0038] (3) Grind the solidified complex precursor from step (2) and spread it flat in a crucible. Place the crucible in a tube furnace and fire it at high temperature. The argon flow rate is 175 sccm. The temperature is increased to 200℃ at 5℃ / min and held for 2 hours.

[0039] (4) When the heat preservation in step (3) ends, the argon flow rate remains unchanged, the temperature of the tube furnace is increased to 500℃ at 2℃ / min, and the heat preservation is carried out for 4 hours. Then the heating is turned off, and the sample is cooled to room temperature with the furnace.

[0040] (5) The calcined boron oxynitride carbon was ground, then placed in ethanol, centrifuged at 6000 r / min for 3 min, and dried. The sample was named BO. 0.05 -CN (the molar percentage of the complex precursor in the total BO is 0.05).

[0041] Example 2: The amorphous boron-oxygen-nitrogen photocatalyst provided in this example has a boron content of 5.2 wt%, an oxygen content of 7.1 wt%, and the remainder is a carbon nitride structure composed of carbon aziridine rings;

[0042] The preparation method includes the following steps:

[0043] (1) Weigh 310 mg of boric acid and 1.26 g of melamine respectively, and place them in beakers. Mix them with 3 mL and 4 mL of deionized water respectively at 94 °C, and keep warm for 20 minutes to obtain boric acid solution and melamine suspension.

[0044] (2) Pour the boric acid solution from step (1) into the melamine suspension, mix it, stir, keep warm, and carry out a dehydration complexation reaction for 10 min to obtain the complex precursor, and then cure it at 80℃ for 12 h.

[0045] (3) Grind the dried complex precursor from step (2) and spread it evenly in a crucible. Place the crucible in a tube furnace and fire it at high temperature. The argon flow rate is 200 sccm. The temperature is increased to 240℃ at 5℃ / min and held for 2 hours.

[0046] (4) When the heat preservation in step (3) ends, the argon flow rate remains unchanged, the temperature of the tube furnace is increased to 510°C at 3°C / min, and the heat preservation is carried out for 4 hours. Then the heating is turned off, and the sample is cooled to room temperature with the furnace.

[0047] (5) The calcined boron oxynitride carbon was ground, then placed in ethanol, centrifuged at 6000 r / min for 3 min, and dried. The sample was named BO. 0.5 -CN.

[0048] Example 3: The amorphous boron-oxygen-nitrogen photocatalyst provided in this example has a boron content of 8.5 wt%, an oxygen content of 12.2 wt%, and the remainder is a carbon nitride structure composed of carbon aziridine rings;

[0049] The preparation method includes the following steps:

[0050] (1) Weigh 465 mg of boric acid and 1.26 g of melamine respectively, and place them in beakers. Mix them with 3 mL and 4 mL of deionized water respectively at 95 °C, and keep warm for 25 minutes to obtain boric acid solution and melamine suspension.

[0051] (2) Pour the boric acid solution from step (1) into the melamine suspension, mix it with the solution, stir it, and keep it warm for 10 min to carry out the dehydration complexation reaction to obtain the complex precursor. Then, cure it at 90℃ for 12 h.

[0052] (3) Mix the dried complex precursors from step (2), spread them evenly in a crucible, place the crucible in a tube furnace and fire it at high temperature. The argon flow rate is 200 sccm, the temperature is increased to 270℃ at 5℃ / min and held for 1.5 hours.

[0053] (4) When the heat preservation in step (3) ends, the argon flow rate remains unchanged, the temperature of the tube furnace is increased to 520°C at 5°C / min, and the heat preservation is carried out for 3.5 hours. Then the heating is turned off, and the sample is cooled to room temperature with the furnace.

[0054] (5) The calcined boron oxynitride carbon was ground, then placed in ethanol, centrifuged at 8000 r / min for 3 min, and dried. The sample was named BO. 0.75 -CN.

[0055] Example 4: The amorphous boron-oxygen-nitrogen photocatalyst provided in this example has a boron content of 10 wt%, an oxygen content of 15.4 wt%, and the remainder is a carbon nitride structure composed of carbon aziridine rings;

[0056] The preparation method includes the following steps:

[0057] (1) Weigh 305 mg of boric acid and 630 mg of melamine respectively, and place them in beakers. Mix them with 3 mL and 4 mL of deionized water respectively at 97 °C, and keep warm for 15 minutes to obtain boric acid solution and melamine suspension.

[0058] (2) Pour the boric acid solution from step (1) into the melamine suspension, mix it with the solution, stir it, and keep it warm for 5 minutes to carry out the dehydration complexation reaction to obtain the complex precursor. Then, cure it at 100°C for 12 hours.

[0059] (3) Mix the dried complex precursor from step (2), spread it evenly in a crucible, place the crucible in a tube furnace and fire it at high temperature. The argon flow rate is 250 sccm, the temperature is increased to 300℃ at 5℃ / min and held for 1 hour.

[0060] (4) When the heat preservation in step (3) ends, the argon flow rate is increased to 300 sccm, the temperature of the tube furnace is increased to 520℃ at 5℃ / min, and the heat preservation is carried out for 4 hours. Then the heating is turned off, and the sample is cooled to room temperature with the furnace.

[0061] (5) The calcined boron oxynitride carbon was ground and then placed in ethanol. After centrifugation at 8000 r / min for 3 min, the sample was dried and named BO1-CN.

[0062] Comparative Example 1: The amorphous carbon nitride provided in this comparative example is prepared by the following steps:

[0063] (1) Weigh 1.26g of melamine, grind it and spread it evenly in a crucible, and then place it in a tube furnace.

[0064] (2) Set the argon flow rate in the tube furnace to 200 sccm, raise the temperature to 300℃ at 5℃ / min and hold for 2 hours.

[0065] (3) When the heat preservation in step (2) ends, the argon flow rate remains unchanged, the temperature of the tube furnace is increased to 520°C at 5°C / min, and the heat preservation is carried out for 4 hours. Then the heating is turned off, and the sample is cooled to room temperature with the furnace.

[0066] (4) The cooled sample was directly ground into powder and named MCN.

[0067] Comparative Example 2: The preparation method of boron-doped crystalline carbon nitride material provided in this comparative example specifically includes the following steps:

[0068] (1) Weigh 310 mg of boric acid and 1.26 g of melamine respectively, grind them evenly and put them into a crucible. The difference from Example 2 is that boric acid and melamine are directly ground and mixed without undergoing a dissolution and dehydration complexation reaction to form a complex precursor.

[0069] (2) Place the crucible in a tube furnace and fire it at high temperature. The argon flow rate is 175 sccm. The temperature is increased to 200℃ at 5℃ / min and held for 2 hours.

[0070] (3) When the heat preservation in step (2) ends, the argon flow rate remains unchanged, the temperature of the tube furnace is increased to 500℃ at 2℃ / min, and the heat preservation is carried out for 4 hours. Then the heating is turned off, and the sample is cooled to room temperature with the furnace.

[0071] (3) The boron-doped carbon nitride obtained by calcination was ground and then placed in ethanol. After centrifugation at 6000 r / min for 3 min, it was dried. The sample was named B-CN (there was no dehydration complexation process in this comparative example, so O atoms could not stably enter the material structure, hence there was no O doping).

[0072] Comparative Example 3: The amorphous boron-oxygen-nitrogen photocatalyst provided in this example has a boron content of 16.5 wt%, an oxygen content of 24.7 wt%, and the remainder is a carbon nitride structure composed of carbon aziridine rings;

[0073] The preparation method includes the following steps:

[0074] (1) Weigh 1.24g of boric acid and 1.26g of melamine respectively, and place them in beakers. Mix them with 3mL and 4mL of deionized water respectively at 97℃, and keep warm for 25 minutes to obtain boric acid solution and melamine suspension.

[0075] (2) Pour the boric acid solution from step (1) into the melamine suspension, mix it with the solution, stir it, and keep it warm for 30 minutes to carry out the dehydration complexation reaction to obtain the complex precursor. Then, cure it at 100°C for 12 hours.

[0076] (3) Mix the dried complex precursors from step (2), spread them evenly in a crucible, place the crucible in a tube furnace and fire it at high temperature. The argon flow rate is 250 sccm, the temperature is increased to 300℃ at 5℃ / min and held for 1.5 hours.

[0077] (4) When the heat preservation in step (3) ends, the argon flow rate remains unchanged, the temperature of the tube furnace is increased to 550°C at 5°C / min, and the heat preservation is carried out for 4 hours. Then the heating is turned off, and the sample is cooled to room temperature with the furnace.

[0078] (5) The calcined boron oxynitride carbon was ground and then placed in ethanol. After centrifugation at 8000 r / min for 3 min, the sample was dried and named BO2-CN.

[0079] The materials prepared in Examples 1-4 and Comparative Examples 1-3 were characterized and tested, and the results are as follows: Figures 1-5 As shown.

[0080] Figure 1Images a, b, c, and d are scanning electron microscope (SEM) images of the materials prepared according to Examples 1, 2, 1 (Comparative Example), and 3 (Comparative Example), respectively. It can be observed that as the proportion of boric acid in the precursor increases, the shape of the prepared boron oxynitride changes and the particle size increases. Compared to the original carbon nitride in Comparative Example 1, the surface of the boron oxynitride is more dense. In Comparative Example 3, the sample is needle-shaped, indicating that the morphology and structure of amorphous boron oxynitride with compositions exceeding those of this invention vary significantly.

[0081] Figure 2 In the images, ab and cd are transmission electron microscope (TEM) images of Example 1 and Example 2, respectively. The presence of crystalline features in the high-resolution TEM images confirms that the prepared boron oxynitride is amorphous.

[0082] Figure 3 The X-ray diffraction (XRD) patterns of Examples 1-4 and Comparative Example 1 show that in boron oxynitride carbon, the diffraction peak width decreases with increasing boric acid content, and the diffraction peak at 13.2° gradually disappears, while the characteristic peak near 43.2° gradually becomes stronger, further proving that boron oxynitride carbon has poor crystallinity and is amorphous.

[0083] Figure 4 These are the X-ray photoelectron spectroscopy (XPS) results from Examples 2, 4, and Comparative Example 1, in BO 0.5 The presence of boron and oxygen atoms was directly observed in -CN and BO1-CN, while only carbon and nitrogen atoms and a small amount of oxygen atoms were found in MCN, confirming that boronic acid in the precursor entered the structure of borooxynitride carbon.

[0084] Figure 5 The transient fluorescence spectra of Example 2 and Comparative Example 1 show that, compared to amorphous carbon nitride, the average electronic lifetime of amorphous boron oxynitride decreased from 9.1 ns to 6.3 ns, indicating a reduced recombination rate of photogenerated electrons and holes.

[0085] Application Example 5: Performance Test of Photocatalytic H2O2 Production

[0086] The amorphous boron oxynitride carbon materials obtained in Examples 1-3, and the amorphous carbon nitride materials obtained in Comparative Examples 1-2 and 3 were used as catalysts to perform photocatalytic synthesis of hydrogen peroxide.

[0087] The specific testing method is as follows: Weigh 50 mg of catalyst and disperse it in 50 mL of pure water, then sonicate for 5 min. The dissolved oxygen concentration in the water is measured using a dissolved oxygen meter. The suspension is then placed under a 300 W xenon lamp light source. After every 10 min of illumination, 2 mL of solution is removed, filtered, and the hydrogen peroxide concentration is measured.

[0088] Figure 6 This is a graph showing the evolution of hydrogen peroxide production versus time over 2 hours in Examples 1-3 and Comparative Examples 1-3 during the photocatalytic reaction. Within 2 hours, the hydrogen peroxide production of all samples increased with time. Specifically, in Example 2 (BO... 0.5 The hydrogen peroxide yield of Example 2 (-CN) was the highest, at 1484 μM. This represents an increase of approximately 14 times compared to the 107 μM hydrogen peroxide yield of amorphous carbon nitride in Comparative Example 1. Compared to Comparative Example 2, Example 2 also showed a 4.8-fold increase in hydrogen peroxide yield, indicating that the dehydration complexation reaction facilitates the construction of a stable boron-oxygen structure within the material, promoting hydrogen peroxide synthesis. Comparative Example 3, however, showed almost no hydrogen peroxide yield, suggesting that amorphous boron-oxygen nitride with components outside the scope of this invention is not suitable for photocatalytic hydrogen peroxide synthesis.

[0089] Figure 7 Examples 2, 4, and Comparative Example 1 show the photocatalytic synthesis yield of hydrogen peroxide under different dissolved oxygen concentrations. Under different dissolved oxygen concentrations, the performance of the boron-oxygen-carbon nitride materials prepared in Examples 2 and 4 is superior to that of the carbon nitride in Comparative Example 1. However, at a dissolved oxygen concentration of only 4.5 mg / L, the performance of the boron-oxygen-carbon nitride materials prepared in Example 2 (BO...) is significantly lower. 0.5 The hydrogen peroxide yield of (CN) remained at 630 μM after 1 hour, while that of Comparative Example 1 (MCN) was only 38 μM. This demonstrates that the amorphous boron oxynitride carbon material has low dependence on dissolved oxygen during photocatalytic synthesis of hydrogen peroxide.

[0090] Figure 8 For the stability test of the photocatalytic synthesis of hydrogen peroxide using boron oxynitride carbon prepared in Example 2, after 30 hours of continuous operation and 5 cycles of recovery, BO 0.5 The yield of hydrogen peroxide synthesized by the CN photocatalytic synthesis remains above 80% of that in the initial reaction, proving that its structure is stable and can be recycled and reused multiple times over a long period of time.

Claims

1. The application of an amorphous boron oxynitride carbon material as a photocatalyst in the photocatalytic synthesis of H2O2, characterized in that, The preparation method of the amorphous boron oxynitride carbon material includes the following steps: (1) Adding boric acid aqueous solution to melamine suspension, mixing and then carrying out dehydration complexation reaction to obtain boron oxynitride carbon complex precursor, followed by curing treatment; the conditions for the dehydration complexation reaction are: reaction at 88-97℃ for 5-30 min; the conditions for the curing treatment are: curing at 80-100℃ for 12-24 h; (2) After the curing treatment, the boron oxynitride carbon complex precursor is ground and then subjected to secondary calcination treatment. After the treatment, it is ground again, then placed in an organic solution, centrifuged and dried to obtain the amorphous boron oxynitride carbon material; the conditions for the first calcination treatment in the secondary calcination treatment are: calcination temperature of 200-300℃, heating rate of 2-10℃ / min, and argon flow rate of 100-250 during calcination. The second calcination treatment involves raising the calcination temperature from the first calcination temperature to 480-550℃ at a rate of 1-5℃ / min, with an argon flow rate of 100-300 sccm and a holding time of 1-4 hours. The resulting amorphous boron-oxygen-nitride carbon material contains 1-10 wt% boron, 2-20 wt% oxygen, and the remainder is a carbon nitride structure composed of carbonazine rings. The photocatalytic synthesis of H2O2 involves adding the amorphous boron-oxygen-nitride carbon material as a photocatalyst to pure water under illumination, with a dissolved oxygen concentration of 2.6-16.4 mg / L.

2. The application according to claim 1, characterized in that, In step (1), the concentration of the boric acid aqueous solution is 0.125-2.5 mmol / mL; the molar ratio of melamine in the melamine suspension to boric acid in the boric acid aqueous solution is 1:0.05-1.

3. The application according to claim 1, characterized in that, In step (1), the boric acid aqueous solution is prepared by dissolving boric acid in water and keeping it at 88-97℃ for 5-30 min. The melamine suspension is prepared by dissolving melamine in water and keeping it at 88-97℃ for 5-30 min.

4. The application according to claim 1, characterized in that, In step (2), the organic solution is ethanol; the centrifugation speed is 6000-8000 r / min and the time is 1-3 min; the drying temperature is 60-80℃ and the time is 12-24 h.

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