Method for activating molecular oxygen by using porous nitrogen-rich carbon nitride photocatalyst
By using porous nitrogen-rich C3N5 photocatalyst, combined with sonication and light, the problems of high activation energy and slow speed during molecular oxygen activation are solved, and efficient photocatalytic activation of molecular oxygen is achieved, and reactive oxygen species are produced during TMB oxidation.
Patent Information
- Application Number
- CN202510193240.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-21
- Publication Date
- 2025-05-23
AI Technical Summary
The prior art requires very high activation energy during the molecular oxygen activation process and the activation process is extremely slow, making it difficult to effectively achieve photocatalytic molecular oxygen activation.
Porous nitrogen-rich C3N5 is used as a photocatalyst, and molecular oxygen is activated by combining sonication and photosynthesis, and react with TMB under visible light irradiation to form reactive oxygen species.
It realizes efficient activation of molecular oxygen under visible light irradiation and produces active oxygen species during TMB oxidation, significantly improving the efficiency of photocatalytic activation of molecular oxygen.
Smart Images
Figure HDA0005280667560000011 
Figure HDA0005280667560000012
Abstract
Description
Technical Field
[0001] The invention relates to the application of a photocatalyst in activating molecular oxygen, and in particular to a method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst. Background Art
[0002] O 2 Commonly found in the natural environment, with an abundance of about 21% in air, it participates in most naturally occurring redox reactions. 2 Due to its wide range of existence, good safety and availability, molecular oxygen activation technology has received widespread attention. However, due to the spin-ban nature of molecular oxygen, the activation of molecular oxygen under natural conditions requires very high activation energy and the activation process is extremely slow. Photocatalysis can break the spin ban of molecular oxygen and provide energy for the activation of molecular oxygen. As an advanced oxidation process (AOPs), photocatalytic oxidation technology uses sunlight to convert solar energy into chemical energy through photovoltaic conversion to drive a variety of chemical reactions. The activation of molecular oxygen is the main process for converting solar energy into chemical energy, and ROS are important participants in chemical reactions, including superoxide radicals (·O 2 - ), singlet oxygen ( 1 O 2 ), hydrogen peroxide (H 2 O 2 ) and hydroxyl radicals (·OH). Molecular oxygen activation is a practical application of photocatalysis and one of the most important reactions in photocatalysis. In addition, specific modification of photocatalysts can achieve the regulation of molecular oxygen activation pathways and ROS, thereby controlling the reaction pathways and final products in practical application scenarios. Therefore, photocatalytic molecular oxygen activation plays an important role in the selective generation of reaction products. Therefore, photocatalytic molecular oxygen activation technology has attracted more and more attention.
[0003] Graphitic carbon nitride has attracted worldwide attention due to its visible light activity, easy synthesis of low-cost materials, chemical stability and unique layered structure. In-depth research on the generation and detection of ROS in carbon nitride photocatalytic reactions has very important scientific significance and research value for studying the photocatalytic reaction mechanism of semiconductor photocatalysts, improving their photocatalytic activity, and further expanding their applications.
[0004] In terms of the application field of carbon nitride catalyst, it is rarely seen in the research of photocatalytic activation of molecular oxygen. At present, it is rare to see people use carbon nitride to study the types of active oxygen species produced in photocatalytic activation of molecular oxygen. Therefore, in this patent, a method for photocatalytic activation of molecular oxygen by porous nitrogen-rich nitride is proposed, hoping to provide a new path for the development of traditional photocatalytic activation of molecular oxygen and a solvable solution for the emerging photocatalytic activation of molecular oxygen. Summary of the invention
[0005] Based on the above problems, the present invention aims to provide a method for activating molecular oxygen with porous nitrogen-rich carbon nitride photocatalyst.
[0006] The technical solution adopted by the present invention to solve the above problems is:
[0007] A method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst, the specific steps are as follows:
[0008] (1) The porous nitrogen-rich C 3 N 5 Add to the beaker, then add 3,3',5,5'-tetramethylbenzidine, and finally add deionized water and HAc / NaAc buffer solution.
[0009] (2) Treat the above solution with ultrasound, add a magnet and cover the mouth of the beaker with plastic wrap. Place the beaker on a magnetic stirrer and continuously illuminate it with a xenon lamp.
[0010] (3) During the irradiation process, the reaction solution was taken at regular intervals and added to a centrifuge tube. The solid particles were separated from the liquid using a centrifuge, and the absorbance of the obtained supernatant was measured using an ultraviolet spectrophotometer.
[0011] According to the above scheme, in step (1), the porous nitrogen-rich C 3 N 5 The mass of 3,3',5,5'-tetramethylbenzidine is 3-6 mg, the volume of deionized water is 10-20 mL, and the volume of acetic acid buffer is 20-30 mL
[0012] According to the above scheme, in step (1), the HAc / NaAc buffer solution is 6-7 mL of acetic acid (CH 3 COOH) solution into a 150-250 mL volumetric flask and add water to make up to volume. Then weigh 4-5 g of sodium acetate (CH 3 COONa) powder is added into 30-45mL H 2 O beaker until the powder is completely dissolved. Then, transfer 30-45 mL of CH 3 COOH solution, the CH 3 The COONa solution was added to a volumetric flask, mixed evenly, and the pH value was measured to be 2-5 to obtain a HAc / NaAc buffer solution.
[0013] According to the above scheme, in step (2), ultrasonic treatment is carried out at 20-25°C for 5-10 min, and the ultrasonic frequency is 20-50KHZ.
[0014] According to the above scheme, in step (2), the agitator speed is set to 600-900r / min
[0015] According to the above scheme, in step (3), the illumination time is 1-5h, the sampling interval is 50-70min, the reaction solution volume is 2-4mL, and the centrifuge tube capacity is 1-10mL.
[0016] The method for activating molecular oxygen by the porous nitrogen-rich carbon nitride photocatalyst can generate active oxygen species while photocatalytically activating molecular oxygen to oxidize TMB.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] 1. The method for activating molecular oxygen by porous nitrogen-rich carbon nitride photocatalyst of the present invention is to
[0019] Under irradiation of 100 nm, TMB is used as a reaction substrate to react with the photogenerated electrons and holes generated on the catalyst surface. Holes oxidize TMB to produce a blue substance oxTMB, while electrons reduce oxygen to produce active oxygen species. This photocatalytic reaction not only oxidizes TMB, but also effectively reduces oxygen to produce active oxygen species. 3 N 5 Photocatalytic activation of molecular oxygen provides a new path for the development of traditional photocatalytic activation of molecular oxygen and a new solution for the new field of photocatalytic activation of molecular oxygen BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a comparison chart of the photocatalytic activation ability of molecular oxygen by porous nitrogen-rich carbon nitride.
[0021] Figure 2 It is the detection of active oxygen species produced in porous nitrogen-rich carbon nitride system. DETAILED DESCRIPTION
[0022] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the present invention is not limited to the following embodiments.
[0023] Example 1
[0024] A method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst, the specific steps are as follows:
[0025] 5 mg C 3 N 5Add to a 50mL beaker, then add 5mg 3,3',5,5'-tetramethylbenzidine, and finally add 15mL deionized water and 25mL HAc / NaAc buffer solution. After ultrasonic treatment at 30KHZ for 5min, add a magnet and cover the mouth of the beaker with plastic wrap. Place the beaker on a magnetic stirrer, set the speed to 800r / min, and use a 300W xenon lamp to continuously illuminate for 1-5h. During the illumination process, take 3mL of the reaction solution every 1h and add it to a 10mL centrifuge tube. Use a centrifuge to separate the solid particles from the liquid. Set the centrifuge speed to 8000r / min and the centrifugation time to 10min. The absorbance of the obtained supernatant is measured by a UV spectrophotometer.
[0026] Example 2
[0027] A method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst, the specific steps are as follows:
[0028] 5 mg of porous nitrogen-rich C 3 N 5 Add to a 50mL beaker, then add 5mg 3,3',5,5'-tetramethylbenzidine, and finally add 15mL deionized water and 25mL HAc / NaAc buffer solution. After ultrasonic treatment at 30KHZ for 5min, add a magnet and cover the mouth of the beaker with plastic wrap. Place the beaker on a magnetic stirrer, set the speed to 800r / min, and use a 300W xenon lamp to continuously illuminate for 1-5h. During the illumination process, take 3mL of the reaction solution every 1h and add it to a 10mL centrifuge tube. Use a centrifuge to separate the solid particles from the liquid. The centrifuge speed is set to 8000r / min, and the centrifugation time is 10min. The absorbance of the obtained supernatant is measured by a UV spectrophotometer.
[0029] The HAc / NaAc buffer solution described in the above embodiment is prepared by taking 6.48 mL of acetic acid (CH 3 COOH) solution was added to a 250 mL volumetric flask and water was added to make up the volume. Then 4.6487 g of sodium acetate (CH 3 COONa) powder was added into 45 mL of H 2 O beaker until the powder is completely dissolved. Then, transfer 45 mL of CH 3 COOH solution, the CH 3 The COONa solution was added to a volumetric flask, mixed evenly, and the pH value was measured to be 4 to obtain a HAc / NaAc buffer solution.
[0030] like Figure 1 As shown, blank C 3 N 5The photocatalytic activation of molecular oxygen gradually increased, and the absorbance of the solution was 0.9 after 5 hours. 3 N 5 The same activity pattern was shown within 5 hours, but the absorbance at each hour was higher than that of the blank N 5 We can see that porous nitrogen-rich C 3 N 5 The ability to activate molecular oxygen is significantly higher than that of blank N 5 , is blank N 5 1.6 times of that.
[0031] like Figure 2 In order to identify the active species generated during the reaction, we conducted a series of free radical trapping experiments. 3 N 5 In the reaction system with benzoquinone (BQ) as the catalyst, when the superoxide radical anion in the reaction process is captured by benzoquinone (BQ), the absorbance of the solution decreases significantly. When tert-butyl alcohol (TBA) and 1,3-diphenylbenzofuran (DBPF) are used to capture hydroxyl radicals and singlet oxygen, the absorbance of the solution decreases slightly. The above results show that the main active species produced in this experiment is superoxide radicals, followed by hydroxyl radicals and singlet oxygen.
[0032] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and changes without departing from the creative concept of the present invention, and these all belong to the protection scope of the present invention.
Claims
1. A method for photocatalytic activation of molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst, characterized in that: The specific steps are as follows: (1) Add porous nitrogen-rich C3N5 into a beaker, then add 3,3',5,5'-tetramethylbenzidine, and finally add deionized water and HAc / NaAc buffer solution; (2) Ultrasonicate the above solution, add a magnet and cover the mouth of the beaker with plastic wrap. Place the beaker on a magnetic stirrer and continuously illuminate it with a xenon lamp; (3) During the irradiation process, the reaction solution was taken at regular intervals and added to a centrifuge tube. The solid particles were separated from the liquid using a centrifuge, and the absorbance of the obtained supernatant was measured using an ultraviolet spectrophotometer.
2. The method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst according to claim 1, characterized in that: The porous nitrogen-rich C3N5 and 3,3',5,5'-tetramethylbenzidine in step (1) have a mass of 3-6 mg, a volume of deionized water of 10-20 mL, and a volume of acetic acid buffer of 20-30 mL.
3. The method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst according to claim 1, characterized in that: The HAc / NaAc buffer solution in step (1) is prepared by adding 6-7 mL of acetic acid (CH3COOH) solution into a 150-250 mL volumetric flask, adding water to the fixed volume, then weighing 4-5 g of sodium acetate (CH3COONa) powder and adding it into a beaker containing 30-45 mL of H2O, waiting for the powder to completely dissolve, then removing 30-45 mL of CH3COOH solution from the 150-250 mL volumetric flask, adding the prepared CH3COONa solution into the volumetric flask, mixing evenly and measuring the pH value to be 2-5, thereby obtaining a HAc / NaAc buffer solution.
4. The method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst according to claim 1, characterized in that: The ultrasonic treatment in step (2) is to add porous nitrogen-rich C3N5, 3,3',5,5'-tetramethylbenzidine, deionized water and acetic acid buffer solution into a beaker, and perform ultrasonic treatment at 20-25°C for 5-10 minutes, with an ultrasonic frequency of 20-50KHZ.
5. The method for activating molecular oxygen using porous nitrogen-rich carbon nitride photocatalyst according to claim 1, characterized in that: The mixture in step (2) is placed on a magnetic stirrer, and the rotation speed is set to 600-900 r / min.
6. The method for activating molecular oxygen using porous nitrogen-rich carbon nitride photocatalyst according to claim 1, characterized in that: In the step (2), a xenon lamp is used for continuous illumination, the power of the xenon lamp is 300 W and equipped with a filter, and the illumination time is 1-5 hours.
7. The method for activating molecular oxygen using porous nitrogen-rich carbon nitride photocatalyst according to claim 1, characterized in that: During the illumination process in step (3), the reaction solution is taken at regular intervals and added to a centrifuge tube. The interval is 50-70 min, the volume of the reaction solution is 2-4 mL, and the capacity of the centrifuge tube is 1-10 mL.
8. The method according to any one of claims 1 to 6 is a method for activating molecular oxygen using a porous nitrogen-rich carbon nitride photocatalyst.