Preparation of ion liquid modified carbon nitride composite material and photosynthesis of hydrogen peroxide

Abstract

The present application relates to a kind of preparation of ion liquid modified carbon nitride composite and photosynthesis hydrogen peroxide.The present application provides a new type of ion liquid doped carbon nitride photocatalytic synthesis hydrogen peroxide, to solve the existing carbon nitride material photocatalytic synthesis hydrogen peroxide production low and the problem of not high visible light utilization rate.Method: one, the preparation of carbon nitride raw material;Two, the preparation of ion liquid doped carbon nitride sample.The preparation process of the present application is simple and effective, reagent consumption is less and the yield is high;And the photocatalyst provided by the present application can effectively improve the photosynthesis hydrogen peroxide efficiency.The present application is applied to the field of photocatalytic synthesis hydrogen peroxide, and experiment shows that the material has excellent photocatalytic synthesis hydrogen peroxide performance, and the synthesis hydrogen peroxide rate can reach 657 μmol·g ‑1 ·h ‑1 under visible light irradiation.

Description

Technical Field

[0001] This invention relates to the preparation of an ionic liquid-modified carbon nitride photocatalytic material and the photocatalytic synthesis of hydrogen peroxide from water and oxygen. Background Technology

[0002] Fossil fuels have long been a significant energy source globally, widely used in industry, transportation, and power generation. Hydrogen peroxide, as a green and efficient energy material, has broad application prospects in many fields. As a versatile reagent, it is widely used in chemical synthesis, energy storage, and water treatment. Hydrogen peroxide is also an important oxidant and disinfectant, with broad applications in environmental protection, healthcare, and food processing. Traditional hydrogen peroxide production methods heavily rely on industrial chemical processes, presenting challenges such as high energy consumption, high costs, and environmental pollution. With increasing demand for hydrogen peroxide, the scientific community is actively exploring environmentally friendly and efficient production processes. Photocatalytic hydrogen peroxide production, utilizing abundant natural water and oxygen from the air as raw materials and sunlight as energy input, and especially without the use of sacrificial agents, is considered one of the green and sustainable methods.

[0003] Carbon nitride is a novel high-temperature molten salt corrosion resistant material with high hardness, good chemical stability, and excellent thermal and electrical conductivity. It can be used as an inner electrode material and electrolytic membrane material in high-temperature molten salt electrolytic cells. Simultaneously, carbon nitride also possesses certain corrosion resistance and wear resistance, making it suitable for manufacturing ceramics, sandpaper, and other fields. However, current production processes for carbon nitride still face some challenges, such as limited raw material sources, high costs, and complex preparation processes. Therefore, further research and improvement of the preparation process are needed to enhance its performance and stability to meet the application needs of more fields. Ionic liquid-modified carbon nitride exhibits better visible light absorption, maximizing the utilization of visible light. Therefore, using ionic liquid-doped carbon nitride for photocatalytic reactions is feasible.

[0004] Ionic liquids (ILs) are arbitrarily defined as salts with melting points below 1008 °C. Due to several key characteristics of these salts, including low toxicity, negligible vapor pressure under environmental conditions, and high conductivity, ionic liquids have attracted considerable interest in a wide range of diverse applications. A virtually unlimited number of cations and anions can potentially combine to form ionic liquids, which facilitates the design of ionic liquids with specific properties. The most common ionic liquids are based on imidazole, ammonium, phosphorus, and pyridine cations. The solubility of O2 in ionic liquids is reversible, thus possessing significant value for O2 capture and separation applications. Researchers have found that ionic liquids have higher O2 absorption efficiency, and the cation groups play a crucial role in the efficiency of O2 absorption. Therefore, introducing ionic liquids into carbon nitride can effectively increase hydrogen peroxide production, thereby improving the performance of artificial photosynthetic hydrogen peroxide. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of low efficiency in the photocatalytic synthesis of hydrogen peroxide using existing carbon nitride materials, and to provide a method for preparing ionic liquid-modified carbon nitride composite materials and for the photosynthesis of hydrogen peroxide.

[0006] The preparation method of the VIEMBF4 / g-C3N4 composite material of the present invention is carried out according to the following steps: First, a mixture of VIEMBF4 and methanol with a concentration of 5 mmol / L is prepared. A sample of the prepared g-C3N4 is taken and transferred to the prepared mixed solution of ionic liquid and methanol. To ensure uniform dispersion, it is ultrasonically treated at a frequency of 40 kHz for 45-60 min. Then, the suspension is dried in a vacuum oven at 80℃ for 12 h after pre-evacuation to obtain the sample.

[0007] The concentration of VEIMBF4 in methanol mentioned in the above steps is 0.05 mmol·L⁻¹. -1 0.0625 mmol·L -1 0.075 mmol·L -1 .

[0008] The volume of methanol mentioned in the above steps is 20 ml.

[0009] The mass of g-C3N4 mentioned in the above steps is 5 mg.

[0010] The aforementioned VEIMBF4 / g-C3N4 composite material was used for the photocatalytic synthesis of hydrogen peroxide.

[0011] The beneficial effects of this invention are:

[0012] This invention successfully synthesized g-C3N4 material using a solvothermal method with melamine as a raw material. However, this material has poor visible light absorption, and the amount of hydrogen peroxide synthesized by photosynthesis is only 153 μmol·g. -1 ·h -1 Therefore, this invention synthesizes a novel ionic liquid-modified carbon nitride photocatalytic material by reacting ionic liquid with g-C3N4 in a secondary reaction. This material effectively improves visible light absorption, thereby enhancing its performance. Attached Figure Description

[0013] Figure 1 X-ray powder diffraction pattern of VEIMBF4 / g-C3N4 material;

[0014] Figure 2 Infrared spectrum of VEIMBF4 / g-C3N4 material;

[0015] Figure 3 The graph shows the performance of the VEIMBF4 / g-C3N4 material in the photocatalytic synthesis of hydrogen peroxide.

[0016] Figure 4 Scanning electron microscope image of VEIMBF4 / g-C3N4 material. Detailed Implementation

[0017] The present invention will be further illustrated below with examples. These examples are only for illustrating the method of the present invention and do not limit the scope of application of the present invention in any way.

[0018] Example 1: The preparation of an ionic liquid-doped carbon nitride material according to this embodiment is carried out according to the following steps:

[0019] I. Preparation of Carbon Nitride: Melamine (10g) and cyanuric acid (4g) were dispersed in 500mL of water until completely dissolved. The melamine and cyanuric acid solutions were mixed and stirred separately at 80℃. After cooling to room temperature of approximately 25℃, the mixture was washed multiple times with deionized water and purchased anhydrous ethanol, and then dried at 80℃. The resulting powder sample was placed in a sealed quartz ceramic boat and heated from room temperature to 520℃ at a heating rate of 1℃ / min for 4 hours under a N2 atmosphere, finally yielding blocky g-C3N4. Then, a secondary calcination treatment was performed in a semi-sealed ceramic boat under an air atmosphere at 500℃ for 2 hours. After naturally cooling to room temperature, the sample was heated in a 70℃ water bath with HNO3 solution for 2 hours, and then completely dried to obtain the final ultrathin g-C3N4 nanosheets (CN).

[0020] II. Preparation of the composite material: First, prepare 20 mL of a mixture of VEIMBF4 and methanol at a concentration of 5 mmol / L. Take 0.05 g of the prepared g-C3N4 sample and transfer it to the prepared ionic liquid and methanol mixture. To ensure uniform dispersion, sonicate at a frequency of 40 kHz for 45-60 min. Then, dry the suspension in an 80℃ vacuum oven for 12 h after pre-evacuation to obtain the sample.

[0021] To investigate the photocatalytic synthesis of hydrogen peroxide using ionic liquid-doped carbon nitride materials, its visible light photocatalytic hydrogen peroxide synthesis performance was tested using the following method. The test procedure was as follows: Carbon nitride and the composite material were used as photocatalysts, and deionized water was used as the reaction solution. The mixture was sonicated for 30 minutes to form a homogeneous suspension. The suspension was poured into a reactor, and oxygen was introduced for 20 minutes to purge the air from the reactor. A xenon lamp was then used as the light source, and the mixture was irradiated for 30 minutes. The resulting suspension was then filtered through a 1 mL syringe with a filter tip to remove the catalyst, and the liquid was collected. 1 mL of the collected liquid was added to 1 mL of a 66.5 mg / mL potassium iodide solution and 0.5 mL of a 20.4 mg / mL potassium hydrogen phthalate solution. The mixture was thoroughly mixed and allowed to stand for 30 minutes before analysis using a UV-Vis spectrophotometer. Figure 3 As shown, the photocatalytic synthesis efficiency of carbon nitride materials for hydrogen peroxide under visible light is low, only 153%. μ mol·g -1 ·h -1 The composite material exhibited excellent photocatalytic performance in the synthesis of hydrogen peroxide, with a yield of 657 kJ / L. μ mol·g -1 ·h -1 .

Claims

1. The application of an ionic liquid-modified carbon nitride composite material in the photosynthesis of hydrogen peroxide, characterized in that, The ionic liquid-modified carbon nitride composite material is prepared according to the following steps: Preparation of ionic liquid-modified carbon nitride materials: First, a mixed solution of VEIMBF4 and methanol with a concentration of 5 mmol / L was prepared; the prepared g-C3N4 sample was transferred to the prepared mixed solution of ionic liquid and methanol, and ultrasonically treated at a frequency of 40 kHz for 45-60 min to ensure uniform dispersion; then, the suspension was dried in an 80℃ vacuum oven for 12 h after being evacuated to a vacuum beforehand to obtain the sample.

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