A method for visible light catalytic production of h2o2 from a carbon nitride material

Abstract

The application belongs to the field of photocatalysis, and discloses a method for visible light catalytic production of H2O2 by using carbon nitride material, which comprises the following steps: preparing a solution by using amino acid as a promoter, wherein the amino acid contains aromatic heterocycle, amino group and carboxyl group; adding carbon nitride as a photocatalyst into the solution; and performing a photocatalytic reaction for producing H2O2 under the conditions of visible light irradiation and oxygen-containing atmosphere. The method is different from the traditional organic sacrificial agent (isopropyl alcohol, methanol and triethanolamine, etc.) system in that: (1) the amount of the organic sacrificial agent is large, and the cost is high; and (2) the organic sacrificial agent and its oxidation products can occupy the active sites on the surface of the carbon nitride, and thus cause irreversible poisoning and passivation of the catalyst. In the application, the amino acid is used as the promoter, and the significant promotion effect can be achieved, the recycling stability of the catalyst is high, and a new path for visible light catalytic production of H2O2 is realized, which has the characteristics of low cost, high catalytic efficiency, excellent catalyst compatibility and green sustainability.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic hydrogen peroxide production technology, and in particular relates to a method for visible light photocatalytic production of H2O2 using carbon nitride materials. Background Technology

[0002] Hydrogen peroxide (H2O2), as a green and multifunctional oxidant, is widely used in chemical synthesis, environmental remediation, and energy fields. However, its mainstream industrial production method—the anthraquinone process—has inherent drawbacks such as high energy consumption, the generation of toxic byproducts, and the flammability and explosiveness of the raw material system.

[0003] Carbon nitride photocatalytic synthesis of hydrogen peroxide is considered an ideal alternative to the traditional high-energy-consuming anthraquinone method due to its mild reaction conditions, low energy consumption, and environmental friendliness. However, in actual photocatalytic reactions, carbon nitride materials face key scientific challenges such as rapid recombination of photogenerated carriers, sluggish surface reaction kinetics, and insufficient selectivity of target products. These factors severely restrict the conversion efficiency of solar energy to chemical energy. To overcome the bottleneck of low photogenerated charge separation efficiency, introducing sacrificial agents into the reaction system to irreversibly consume photogenerated holes and block electron-hole pair recombination has become the most common kinetic control method. However, traditional alcohol or amine organic sacrificial agents (such as methanol, isopropanol, triethanolamine, etc.) have revealed multiple technical defects in practical applications: First, these high-purity organic reagents are themselves consumables, and their oxidation products are mostly low-value carbon dioxide or small-molecule organic acids that are difficult to separate, which significantly increases the preparation cost of hydrogen peroxide; Second, the oxidation derivatives and acidic byproducts generated by the sacrificial agent during hole capture are very likely to form a strong adsorption passivation layer on the surface of carbon nitride, inducing irreversible poisoning or even structural etching of catalytic active sites, resulting in a decrease in the long-term stability of the catalyst; In addition, the residual aldehydes and organic acid byproducts have non-productive consumption of the target product H2O2, further reducing the actual net yield of the system.

[0004] Therefore, developing novel photocatalytic systems that combine high production efficiency, low environmental impact, and non-toxicity to catalysts has become a pressing technical problem in this field. In this regard, exploring readily available, low-cost, and environmentally compatible alternative sacrificial agents is of significant practical importance for promoting the practical application of carbon nitride photocatalytic hydrogen peroxide production technology. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a system and method for visible light photocatalytic production of H2O2 using carbon nitride materials. This method utilizes a class of amino acids to provide a proton source for the photocatalytic process, participating in proton transfer and promoting electron transfer through a protonation-deprotonation balance. This achieves efficient photocatalytic production of H2O2 from carbon nitride, thereby solving the technical problem of developing novel photocatalytic systems that combine high production efficiency, low environmental impact, and non-toxicity to catalysts.

[0006] To achieve the objectives of this invention, this invention provides a system and method for visible light photocatalytic production of H2O2 using carbon nitride materials, comprising: preparing a solution using amino acids as promoters, wherein the amino acids contain aromatic heterocycles, amino groups, and carboxyl groups; adding carbon nitride as a photocatalyst to the solution; and carrying out a photocatalytic H2O2 production reaction under visible light irradiation and an oxygen-containing atmosphere.

[0007] As a preferred embodiment of the present invention, the amino acid is one or more of L-tryptophan or L-histidine.

[0008] As a preferred embodiment of the present invention, the mass ratio of the amino acid to the carbon nitride is 0.02 to 2.

[0009] As a preferred embodiment of the present invention, the mass ratio of the amino acid to the carbon nitride is 0.2 to 1.

[0010] As a preferred embodiment of the present invention, the carbon nitride is one or more of C3N4, C3N5 and C2N3.

[0011] As a preferred embodiment of the present invention, carbon nitride is added to the solution as a photocatalyst, specifically including: under light-protected conditions, carbon nitride is added to the solution as a photocatalyst and ultrasonically dispersed until adsorption-desorption equilibrium is reached and solid-liquid dispersion is uniform.

[0012] As a preferred embodiment of the present invention, the concentration of the solution prepared by using amino acids as a promoter is 0.02-2 mM, and the pH range is 3-11.

[0013] As a preferred embodiment of the present invention, the visible light irradiation condition is that the cutoff wavelength of the irradiation source filter is >420nm.

[0014] As a preferred embodiment of the present invention, the volume fraction of oxygen in the oxygen-containing atmosphere is 10% to 100%.

[0015] As a preferred embodiment of the present invention, the photocatalytic reaction temperature is 5-45°C.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. This invention provides a method for visible light photocatalytic production of H2O2 using carbon nitride materials. The photocatalytic reaction process involves the photocatalyst absorbing light energy to generate electron-hole pairs, with the electrons reducing oxygen (O2) to generate superoxide radicals (·O2). - H₂O₂ is generated either through direct two-electron reduction or through hole oxidation of water (H₂O) or by organic molecules providing protons. Compared to traditional organic sacrificial agents, amino acids primarily enhance the efficiency of electron participation in ORR by consuming photogenerated holes, suppressing carrier recombination, and providing a proton source for the photocatalytic process. Specifically, in this system, the carboxyl group of the amino acid dissociates in solution to release H₂O. + This provides a continuous supply of protons for the ORR process, promoting proton-coupled electron transfer; simultaneously, amino acids can efficiently capture byproducts generated during the conversion of active species. 1 O2 participates in proton transfer through the protonation-deprotonation balance, driving the reaction toward H2O2 production; and aromatic heterocycles have conjugated structures that can participate in / accelerate electron transfer, which is beneficial to the separation of photogenerated electron-hole pairs. Thus, through the action of the above three functional groups, H2O2 production from carbon nitride can be efficiently promoted under visible light irradiation and mild oxygen-containing conditions. It has the characteristics of good environmental adaptability and strong cycle stability, showing good prospects for industrial application.

[0017] 2. In this invention, the preferred mass ratio of amino acids to carbon nitride catalyst is 0.2–1, and trace amounts of amino acids are used as a promoter, resulting in a significant promoting effect. Furthermore, the raw materials can be prepared on a large scale via microbial fermentation, are widely available and inexpensive, significantly reducing the economic burden of process operation and meeting the requirements of green chemistry and sustainable development.

[0018] 3. The system of this invention exhibits excellent tolerance and adaptability to the reaction environment, and can tolerate various common inorganic anions (such as Cl-). - NO3 - SO4 2- H2PO4 - Under conditions of coexistence of oxygen, oxygen, and other oxygen species, as well as within a wide temperature range (5-45℃), a wide pH range (3-11), and in both natural and pure oxygen atmospheres, it can maintain high-efficiency H2O2 generation performance and has the potential to cope with complex actual working conditions.

[0019] 4. The visible light catalytic H2O2 production system provided by this invention exhibits significant technical advantages and wide applicability. It preferably shows good catalytic promotion effect on carbon nitride-based photocatalytic materials with different chemical compositions (including but not limited to C3N4, C3N5 and C2N3, etc.), demonstrating broad compatibility with catalyst types. Attached Figure Description

[0020] Figure 1 A comparison of the H2O2 production performance of different photocatalytic systems for C2N3.

[0021] Figure 2 The photocatalytic recycling performance of the system is an example of Example 1 of the present invention.

[0022] Figure 3 FT-IR characterization of the catalyst C2N3 before and after recycling, as exemplified in Example 1 of this invention.

[0023] Figure 4 The photocatalytic recycling performance of the system in Comparative Example 1 of this invention is shown.

[0024] Figure 5 The effect of L-tryptophan on the photocatalytic H2O2 production performance of various carbon nitride materials. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] To achieve the above objectives, the present invention provides the following technical solution: A method for visible-light photocatalytic production of H2O2 using carbon nitride materials is disclosed. In this method, carbon nitride serves as the photocatalyst, and amino acids are used as promoters. The amino acids contain aromatic heterocycles, amino groups, and carboxyl groups, and can promote the stable and efficient generation of H2O2 under visible light irradiation and an oxygen-containing atmosphere. A key advantage is that traditional organic sacrificial agent systems (such as isopropanol, methanol, and triethanolamine) suffer from two problems: firstly, they require large quantities and are costly; secondly, these organic sacrificial agents and their oxidation products occupy the active sites on the carbon nitride surface, leading to irreversible poisoning and passivation of the catalyst. In this invention, amino acids, acting as promoters, can dissociate and release H2O2 in solution through the carboxyl groups in their molecular structure. + This catalyst achieves a significant promoting effect by participating in proton transfer through the amino protonation-deprotonation balance and by participating in / accelerating electron transfer through the conjugated structure of aromatic heterocycles, and also exhibits high cycling stability. Furthermore, amino acids are widely available, inexpensive, and readily biodegradable, avoiding the high consumption costs and secondary pollution problems of traditional sacrificial agents.

[0027] A method for visible light photocatalytic production of H2O2 using carbon nitride materials includes: (1) At room temperature, amino acids are dissolved in deionized water to prepare a solution; wherein the amino acids contain aromatic heterocycles, amino groups and carboxyl groups; (2) Carbon nitride powder was added to the solution as a photocatalyst and mixed evenly until adsorption-desorption equilibrium was reached to obtain a suspension; (3) Under visible light irradiation and an ambient oxygen atmosphere, the above suspension was subjected to a photocatalytic reaction to produce H2O2.

[0028] In the aforementioned visible light photocatalytic H2O2 production system, the amino acids contain aromatic heterocycles, amino groups, and carboxyl groups. Compared to traditional organic sacrificial agents, they primarily improve the efficiency of electron participation in ORR by consuming photogenerated holes, suppressing carrier recombination, and providing a proton source for the photocatalytic process. Specifically, in the system of this invention, the carboxyl groups on the amino acid molecules can dissociate and release H2O2. + Amino acids continuously supply protons to the ORR process, promoting proton-coupled electron transfer; moreover, they can efficiently capture byproducts generated during the conversion of active species. 1 O2 participates in proton transfer through the protonation-deprotonation balance, driving the reaction toward H2O2 production; and the conjugated structure of aromatic heterocycles participates in / accelerates electron transfer, which is beneficial to the separation of photogenerated electron-hole pairs. Thus, through the action of the above three functional groups, H2O2 production can be promoted efficiently by carbon nitride under visible light irradiation and mild oxygen-containing conditions.

[0029] •O2 - + H + → •O2H (Equation 1) 2•O2H → H2O2+ 1 O2 (Formula 2) Preferably, the amino acid is one or more of L-tryptophan or L-histidine, and its carboxyl group can dissociate to release H+. + It continuously supplies protons to the ORR process, promoting proton-coupled electron transfer, and can also efficiently capture byproducts generated during the conversion of active species. 1 O2 drives the reaction toward the formation of H2O2.

[0030] Preferably, the carbon nitride photocatalyst includes, but is not limited to, one or more of C3N4, C3N5 and C2N3, meaning that this method exhibits good catalytic promotion effects on carbon nitride-based photocatalytic materials with different chemical compositions.

[0031] Preferably, the mass ratio of amino acids to carbon nitride catalyst is 0.02-2, and more preferably, the mass ratio of amino acids to carbon nitride catalyst is 0.2-1. That is, a trace amount of biomass amino acids is used as a promoter, which has a small dosage and excellent promoting effect.

[0032] Preferably, carbon nitride is added to the solution as a photocatalyst, specifically including: under light-protected conditions, carbon nitride is added to the solution and ultrasonically dispersed until adsorption-desorption equilibrium is reached and solid-liquid dispersion is uniform.

[0033] Preferably, amino acids are used as promoters dissolved in deionized water to prepare solutions with a concentration of 0.02-2 mM and a pH range of 3-11. The high efficiency of H2O2 generation can be maintained within a wide pH range (3-11), indicating that the selectivity of the amino acid-promoted H2O2 production pathway is not affected, and that the amino acid itself is not easily decomposed or denatured at different pH levels.

[0034] Preferably, the visible light irradiation condition is that the cutoff wavelength of the irradiation source filter is >420 nm, preferably a 300 W Xe lamp with a cutoff wavelength of >420 nm.

[0035] Preferably, the volume fraction of oxygen in the oxygen-containing atmosphere is 10% to 100%, including low-oxygen environments, natural ambient oxygen, and pure oxygen atmospheres.

[0036] Preferably, the photocatalytic reaction temperature is 5-45℃. The fact that the system can maintain high efficiency in H2O2 generation over a wide temperature range indicates that the reaction barrier is low.

[0037] Conventional photocatalytic H2O2 production typically relies on high concentrations of organic sacrificial agents (such as alcohols), leading to high production costs and secondary pollution. The proposed solution significantly reduces the amount of promoter required, necessitating only a trace amount for efficient reaction acceleration. Furthermore, this system exhibits excellent adaptability to temperature, pH, and coexisting anions, lowering the requirements for the reaction environment and demonstrating application potential in industrial production, environmental remediation, pharmaceuticals, and clean energy. In summary, this invention enables highly efficient visible-light photocatalytic H2O2 production based on carbon nitride materials in both natural air atmospheres and complex environments.

[0038] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can understand it.

[0039] Example 1: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan aqueous solution, add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25°C, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic production of hydrogen peroxide. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0040] Example 2: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 0.05 mM L-tryptophan aqueous solution, add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25°C, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm with a spectrophotometer.

[0041] Example 3: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 2 mM L-tryptophan aqueous solution, add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25°C, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm with a spectrophotometer.

[0042] Example 4: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan aqueous solution, add 2 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25°C, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm with a spectrophotometer.

[0043] Example 5: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan aqueous solution, add 50 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25°C, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm with a spectrophotometer.

[0044] Example 6: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan aqueous solution, add 20 mg of C3N4 to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25°C, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm with a spectrophotometer.

[0045] Example 7: This embodiment provides a system for visible light photocatalytic H2O2 production using carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan aqueous solution, add 20 mg of C3N5 to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25°C, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0046] Example 8: This embodiment provides a system for visible light photocatalytic H2O2 production using carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan aqueous solution, add 20 mg of C2N3-Ar to 100 ml of the above solution, sonicate for 5 min, stir and adsorb in the dark for 1 h, transfer the solution to a reactor and adjust the reaction temperature to 25℃, and irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0047] Example 9: This embodiment provides a system for visible light photocatalytic H2O2 production using carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a mixed solution of 1 mM L-tryptophan and 10 mM sodium chloride. Add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, and then stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25°C. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0048] Example 10: This embodiment provides a visible-light photocatalytic H2O2 production system using carbon nitride materials under an oxygen atmosphere. The specific steps are as follows: Prepare a mixed solution of 1 mM L-tryptophan and 10 mM sodium nitrate. Add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, and then stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25°C. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0049] Example 11: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a mixed solution of 1 mM L-tryptophan and 10 mM sodium sulfate. Add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, and then stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25°C. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0050] Example 12: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a mixed solution of 1 mM L-tryptophan and 10 mM sodium dihydrogen phosphate. Add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, and then stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25°C. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0051] Examples 13-17: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: L-tryptophan at a concentration of 1 mM was prepared, and the pH of the solution was adjusted to 3, 5, 7, 9, and 11, respectively. 20 mg of C2N3 was added to 100 ml of the above solution, and the mixture was sonicated for 5 min, then stirred and adsorbed in the dark for 1 h. The solution was transferred to a reactor, and the reaction temperature was adjusted to 25°C. The H2O2 photocatalytic reaction was carried out using a 300 W xenon lamp equipped with a 420 nm cutoff filter. After 3 h of reaction, the H2O2 concentration was calculated by measuring the absorbance at 350 nm using an iodometric titration method.

[0052] Examples 18-21: This embodiment provides a system for the visible light photocatalytic production of H2O2 from carbon nitride materials under an oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan solution, add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, and then stir and adsorb for 1 h in the dark. Transfer the solution to a reactor and adjust the reaction temperature to 5, 15, 35, and 45 °C respectively. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0053] Example 22: This embodiment provides a system for visible light photocatalytic H2O2 production using carbon nitride materials under an ambient oxygen atmosphere. The specific operation steps are as follows: Prepare a 1 mM L-tryptophan solution, add 20 mg of C2N3 to 100 ml of the above solution, sonicate for 5 min, and then stir and adsorb for 1 h in the dark. Transfer the solution to a reactor, adjust the reaction temperature to 25℃, and adjust the reaction environment to a pure oxygen atmosphere. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, use iodometric titration for color development, and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0054] Comparative Example 1: The specific operating steps for this comparative example are as follows: Prepare a 10 vol% isopropanol solution. Add 20 mg of C2N3 to 100 ml of the above solution. After sonication for 5 min, stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25℃. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, perform colorimetric analysis using the iodometric method and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0055] Comparative Example 2: The specific operating steps for this comparative example are as follows: Prepare a 10 vol% isopropanol solution. Add 20 mg of C3N4 to 100 ml of the above solution. After sonication for 5 min, stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25℃. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, perform colorimetric analysis using the iodometric method and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0056] Comparative Example 3: The specific operating steps for this comparative example are as follows: Prepare a 10 vol% isopropanol solution. Add 20 mg of C3N5 to 100 ml of the above solution. After sonication for 5 min, stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25℃. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, perform colorimetric analysis using the iodometric method and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0057] Comparative Example 4: The specific operating steps for this comparative example are as follows: Prepare a 10 vol% isopropanol solution. Add 20 mg of C2N3-Ar to 100 ml of the above solution. After sonication for 5 min, stir and adsorb in the dark for 1 h. Transfer the solution to a reactor and adjust the reaction temperature to 25℃. Irradiate with a 300 W xenon lamp equipped with a 420 nm cutoff filter to carry out the photocatalytic H2O2 production reaction. After 3 h of reaction, perform colorimetric analysis using the iodometric method and calculate the H2O2 concentration by measuring the absorbance at 350 nm using a spectrophotometer.

[0058] Table 1: Comparison of conditional and yield results used in the above embodiments and comparative examples:

[0059] As shown in Table 1 above, the yield of H2O2 prepared by the method of Example 1 of the present invention is approximately 3.4 times higher than that of the method of Comparative Example 1 under the same conditions. Examples 2 and 4 respectively demonstrate that using small amounts of photocatalyst and sacrificial agent can achieve the same effect as organic alcohol sacrificial agents. Examples 9-12 demonstrate that the system of the present invention has good tolerance to inorganic salt environments. Examples 13-17 demonstrate that the scheme of the present invention has a wide applicable pH range, and Examples 18-22 demonstrate that the scheme of the present invention has a wide applicable temperature range. Furthermore, in conjunction with... Figure 1 A comparison of the H2O2 production performance of different photocatalytic systems for C2N3 shows that the visible light photocatalytic H2O2 production system of the carbon nitride material of this invention has significant advantages.

[0060] Combination Figure 2 and Figure 4 The photocatalytic system constructed in this invention (Example 1) retains over 90% of its initial activity even after 8 cycles, exhibiting higher stability and yield compared to existing alcohol sacrificial agent systems (Comparative Example 1). Furthermore, combined with... Figure 3 The FT-IR characterization images of the photocatalyst used in Example 1 before and after use show that the solution of the present invention has minimal poisoning effect on the photocatalyst and does not affect its catalytic activity and structural stability. Figure 5 This demonstrates that the photocatalytic system of the present invention has a significant promoting effect on different carbon nitride materials and has excellent application potential.

[0061] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of protection of this invention and its equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for visible light photocatalytic production of H2O2 using carbon nitride materials, characterized in that, include: A solution is prepared using an amino acid as a promoter, wherein the amino acid contains aromatic heterocycles, amino groups, and carboxyl groups; Carbon nitride was added to the solution as a photocatalyst, and the photocatalytic H2O2 production reaction was carried out under visible light irradiation and an oxygen-containing atmosphere.

2. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The amino acid is one or more of L-tryptophan or L-histidine.

3. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The mass ratio of the amino acid to the carbon nitride is 0.02 to 2.

4. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The mass ratio of the amino acid to the carbon nitride is 0.2 to 1.

5. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The carbon nitride is one or more of C3N4, C3N5 and C2N3.

6. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The addition of carbon nitride as a photocatalyst to the solution specifically includes: under light-protected conditions, adding carbon nitride as a photocatalyst to the solution and ultrasonically dispersing it until adsorption-desorption equilibrium and uniform solid-liquid dispersion are achieved.

7. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The concentration of the solution prepared using amino acids as a promoter is 0.02–2 mM, and the pH range is 3–11.

8. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The visible light irradiation condition is that the cutoff wavelength of the irradiation source filter is >420nm.

9. The method for visible light photocatalytic production of H2O2 from carbon nitride material according to claim 1, characterized in that, The oxygen volume fraction in the oxygen-containing atmosphere is 10% to 100%.

10. The method for visible light photocatalytic production of H2O2 from carbon nitride materials according to claim 1, characterized in that, The photocatalytic reaction temperature is 5-45℃.

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