A high-coordination iron single-atom catalyst for electro-Fenton high-selectivity generation of singlet oxygen, a preparation method thereof, and an application thereof

Abstract

The present invention discloses a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen, a preparation method thereof, and an application thereof. The catalyst uses graphitic carbon nitride as a carrier, in which iron single atoms are coordinated with six nitrogen atoms, making the oxidation state of the iron single atoms approach +3 valence and showing a high-spin state. During the electro-Fenton process, only singlet oxygen is generated, and thus it has good selectivity and anti-interference ability during the degradation of pollutants; the preparation method includes the following steps: mixing cyanuric acid, melamine, iron acetylacetonate, and an alcohol organic matter, and performing ball milling to obtain a precursor; calcining the precursor to obtain a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen, and its application in catalytic degradation of organic pollutants. The preparation method provided by the present invention can successfully prepare a high-coordination iron single-atom catalyst, and has simple operation and low production cost.

Description

Technical Field

[0001] The present invention relates to the field of single-atom catalytic electro-Fenton degradation of persistent organic pollutants, and particularly to a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen, a preparation method thereof, and an application thereof. Background Art

[0002] With the improvement of the economic level, people's requirements for environmental quality are getting higher and higher. Persistent organic pollutants in most industrial wastewaters are highly toxic and difficult to degrade, seriously endangering human health. For the degradation of wastewater containing such refractory pollutants, advanced oxidation technologies have been widely studied due to their advantages such as high oxidation efficiency and strong mineralization ability. Among them, the electro-Fenton technology has been increasingly favored because of its wide application range and simple energy requirements. However, the electrode materials in the electro-Fenton system are mostly noble metals, with high costs and only good effects under acidic conditions. Currently, in the electro-Fenton system, the active species are mostly free radicals, but free radicals are easily interfered with in water bodies, and their efficiency in complex water bodies is reduced, and the free radical lifetime is short (<1 μs). And 1 1O2 has a stronger anti-interference ability to the environment and a higher tolerance to the water matrix compared with free radicals such as ·OH; it has a longer lifetime (1 h in the gas phase, 2 - 3.5 μs in the solution); it can also inhibit the generation of halogenated disinfection by-products. However, in the electro-Fenton reaction system 1 the selective generation of 1O2 is difficult to achieve because the cleavage of the O - O bond in its reaction process is difficult to regulate. Currently, many related studies have completed maintaining the non-cleavage of the O - O bond in the rate-determining step (*O2 to *OOH), thereby generating H2O2. However, the generated H2O2 is further oxidized and decomposed into ·OH due to the elongation of the O - O bond. Therefore, it is necessary to find an electro-Fenton technology for highly selectively generating 1 1O2 to efficiently degrade persistent organic pollutants in water. Summary of the Invention

[0003] The purpose of the present invention is to solve the technical problems existing in the prior art, and provide a preparation method and an application of a high-coordination iron single-atom catalyst.

[0004] To achieve the above purpose, the technical solution provided by the present invention is: a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen, in which the high-coordination iron single-atom active sites in the high-coordination iron single-atom catalyst are loaded on graphitic carbon nitride in a six-coordination form, and the iron presents a high-spin state; the mass content of iron single atoms in the high-coordination iron single-atom catalyst is 2.49% - 12.88%; the contribution rate of singlet oxygen in the process of electro-Fenton degradation of pollutants by the high-coordination iron single-atom catalyst is close to 100%.

[0005] Furthermore, the high-coordination iron single-atom in the high-coordination iron single-atom catalyst has a six-coordination configuration, which has a regulatory effect on the oxidation state and spin state of the metal center.

[0006] The present invention also discloses a preparation method of a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen, and the preparation method includes the following steps:

[0007] (1) Add cyanuric acid, melamine, and iron acetylacetonate into a ball milling jar according to a certain molar ratio, and then add an appropriate amount of alcohol organic matter;

[0008] (2) Ball mill the ball milling jar in step (1) at an appropriate rotation speed and time to obtain a precursor;

[0009] (3) Calcinate the precursor obtained in step (2) to obtain a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen.

[0010] Furthermore, the alcohol organic matter in step (1) includes one or both of methanol and ethanol.

[0011] Furthermore, the molar ratio of cyanuric acid:melamine:iron acetylacetonate in step (1) is (0.4 - 0.9):(0.6 - 1.0):(0.025 - 0.1).

[0012] Furthermore, the calcination temperature in step (3) is 550 - 850 °C, the time is 1 - 7 h, and the calcination is carried out under a protective atmosphere.

[0013] The present invention also discloses an application of a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen, including the application of a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen as described above and a high-coordination iron single-atom catalyst obtained by the preparation method of a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen as described above in the catalytic degradation of organic pollutants.

[0014] Specifically, the application includes the following steps:

[0015] Disperse the high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen in a naphthol-ethanol aqueous solution, drop-coat it on the surface of carbon paper, serve as a working electrode, form a three-electrode system with a reference electrode and a counter electrode, mix the electrolyte and the persistent organic pollutant to be treated, and apply a voltage under continuous oxygen supply for degradation.

[0016] Advantages of the present invention:

[0017] In the present invention, graphitic carbon nitride is used as a carrier, in which iron single atoms are coordinated with six nitrogen atoms, making the oxidation state of iron single atoms approach +3 and showing a high-spin state. Only singlet oxygen is generated during the electro-Fenton process, and thus there are good selectivity and anti-interference ability in degrading pollutants.

[0018] The preparation method provided by the present invention can successfully prepare a high-coordination iron single-atom catalyst, and has the advantages of simple operation and low production cost. Brief Description of the Drawings

[0019] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0020] Figure 1 XRD patterns of the FeN6 / CN obtained in Example 1, the FeN4 / CN obtained in Comparative Example 1, and the CN sample obtained in Comparative Example 2;

[0021] Figure 2 FT-IR spectra of the FeN6 / CN obtained in Example 1, the FeN4 / CN obtained in Comparative Example 1, and the CN sample obtained in Comparative Example 2;

[0022] Figure 3 TEM image of the FeN6 / CN sample obtained in Example 1;

[0023] Figure 4 Element distribution map of the FeN6 / CN sample obtained in Example 1;

[0024] Figure 5 AC-HAADF-STEM image of the FeN6 / CN sample obtained in Example 1;

[0025] Figure 6 XANES spectrum of the FeN6 / CN sample obtained in Example 1;

[0026] Figure 7 EPR spectra of the FeN6 / CN obtained in Example 1 and the FeN4 / CN obtained in Comparative Example 1;

[0027] Figure 8 Degradation efficiency graphs of the electro-Fenton degradation of 4-CP by the FeN6 / CN obtained in Example 1, the FeN4 / CN obtained in Comparative Example 1, and the CN sample obtained in Comparative Example 2;

[0028] Figure 9 Results graph of the radical quenching experiment for the electro-Fenton degradation of 4-CP by the FeN6 / CN obtained in Example 1;

[0029] Figure 10 Using 9,10-dimethylanthracene (DMA) as1 O2 probe, fluorescence spectra of the reaction solution obtained by electro-Fenton catalyzed by FeN6 / CN obtained in Example 1, where a is the control group, and b is the quenching of ·O2 - Fluorescence spectra of the obtained reaction solution, and c is the fluorescence spectra of the reaction solution obtained by quenching H2O2;

[0030] Figure 11 It is the influence diagram of cations and anions during the degradation of 4-CP by electro-Fenton catalyzed by FeN6 / CN obtained in Example 1;

[0031] Figure 12 It is the influence diagram of different pH values during the degradation of 4-CP by electro-Fenton catalyzed by FeN6 / CN obtained in Example 1. Detailed implementation manners

[0032] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The role of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the protection scope of the present invention.

[0033] In the description of the present invention, it should be understood that for the orientation description, such as the upper, lower, front, rear, left, right, etc., the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation on the present invention.

[0034] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is more than two, greater than, less than, exceeding, etc. are understood as not including the original number, above, below, within, etc. are understood as including the original number. If the first and second are described only for the purpose of distinguishing technical features, they cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0035] In the description of the present invention, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0036] Refer to Figures 1-12, Preferred embodiment of the present invention. The present invention provides a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen. The high-coordination iron single-atom active sites in the high-coordination iron single-atom catalyst are loaded on graphitic carbon nitride in a six-coordination form, and the iron presents a high-spin state; the mass content of iron single atoms in the high-coordination iron single-atom catalyst is 2.49% - 12.88%, further preferably 5% - 10%, and more preferably 5%. The iron single atoms are distributed inside and on the surface of the carrier; the contribution rate of singlet oxygen in the process of electro-Fenton degradation of pollutants by the high-coordination iron single-atom catalyst is close to 100%.

[0037] Furthermore, the iron single atoms in the high-coordination iron single-atom catalyst have a six-coordination configuration, which has a regulatory effect on the oxidation state and spin state of the metal center.

[0038] The present invention also discloses a preparation method of a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen. The preparation method includes the following steps:

[0039] (1) Add cyanuric acid, melamine, and iron acetylacetonate to a ball milling jar according to a certain molar ratio, and then add an appropriate amount of alcohol organic matter;

[0040] (2) Ball mill the ball milling jar in step (1) at an appropriate rotation speed and time to obtain a precursor;

[0041] (3) Calcinate the precursor obtained in step (2) to obtain a high-coordination iron single-atom catalyst for electro-Fenton to highly selectively generate singlet oxygen.

[0042] The iron single-atom catalyst prepared by the present invention is a six-coordination single-atom catalyst with graphitic carbon nitride as the carrier. On the carrier of the present invention, the increase in the coordination number not only raises the valence state of the iron single atoms, but also changes the spin state of the metal center, enabling highly selective generation of singlet oxygen, further degrading persistent organic pollutants, avoiding the phenomenon that hydroxyl radicals in traditional electro-Fenton processes are easily interfered, and realizing specific detoxification treatment of persistent organic pollutants.

[0043] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0044] The alcohol organic matter in the present invention preferably includes one or both of methanol and ethanol.

[0045] The ball milling rotation speed in the present invention is preferably 350 - 500 rpm, and more preferably 400 rpm - 450 rpm. The ball milling time in the present invention is preferably 2 - 6 h, and more preferably 3.5 - 5 h.

[0046] In the present invention, the molar ratio of cyanuric acid:melamine:iron acetylacetonate is preferably (0.4 - 0.9):(0.6 - 1.0):(0.025 - 0.1), more preferably (0.6 - 0.8):(0.8 - 0.9):(0.05 - 0.07).

[0047] In the present invention, the temperature of ball milling is preferably room temperature, and no additional temperature change is required.

[0048] In the present invention, the calcination temperature is preferably 550 - 850 °C, more preferably 600 - 700 °C; the calcination time is preferably 1 - 7 h, more preferably 3 - 5 h. In the present invention, the calcination is preferably carried out under a protective atmosphere, and the protective atmosphere is preferably argon / nitrogen. In the present invention, the heating rate to the calcination temperature is preferably 3 - 5 °C / min.

[0049] The present invention also discloses an application of a high - coordination iron single - atom catalyst for electro - Fenton to highly selectively generate singlet oxygen, including the application of a high - coordination iron single - atom catalyst for electro - Fenton to highly selectively generate singlet oxygen as described above and the high - coordination iron single - atom catalyst obtained by the preparation method of a high - coordination iron single - atom catalyst for electro - Fenton to highly selectively generate singlet oxygen as described above in the catalytic degradation of organic pollutants.

[0050] In the present invention, the application preferably includes the following steps:

[0051] Disperse the high - coordination iron single - atom catalyst for electro - Fenton to highly selectively generate singlet oxygen in a naphthol - ethanol aqueous solution, drop - coat it on the surface of carbon paper to serve as a working electrode, and form a three - electrode system with a reference electrode and a counter electrode. Mix the electrolyte and the persistent organic pollutant to be treated, and apply a voltage under continuous oxygen supply for degradation.

[0052] In the naphthol - ethanol aqueous solution, the volume ratio of naphthol:ethanol:water is preferably (1 - 3):(25 - 45):(20 - 30); the concentration of the high - coordination single - atom catalyst in the naphthol - ethanol aqueous solution is preferably 5 - 20 mg / mL, more preferably 10 - 15 mg / mL. In the present invention, the water is preferably deionized water or ultrapure water, more preferably ultrapure water.

[0053] In the present invention, the self - supporting electrode preferably includes carbon paper, carbon cloth, carbon felt, nickel foam, copper foam; the reference electrode preferably includes a silver / silver chloride electrode, a saturated calomel electrode, a mercury / mercuric oxide electrode, and a mercurous sulfate electrode; the counter electrode preferably includes a graphite carbon electrode, a platinum metal electrode.

[0054] In the present invention, the electrolyte preferably includes one or more of sodium sulfate, potassium hydroxide, and potassium bisulfate.

[0055] In the present invention, the persistent organic pollutants to be treated preferably include one or more of p-chlorophenol, dichlorophenol, trichlorophenol, and phenol.

[0056] In the present invention, the purity of the oxygen is preferably high purity, and the oxygen flow rate is preferably 20 - 80 mL / min, more preferably 40 - 60 mL / min.

[0057] In the present invention, the applied voltage is preferably -1.2 to -0.6 V (relative to the silver / silver chloride electrode), more preferably -1.0 to -0.8 V (relative to the silver chloride electrode).

[0058] In the present invention, the temperature for the application of degradation is preferably room temperature, and the degradation time is preferably 1.5 - 2.5 h.

[0059] The preparation method and application of highly selective generation of singlet oxygen by catalytic electro-Fenton using a high-coordination iron single-atom catalyst provided by the present invention will be described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0060] Example 1

[0061] (1) Weigh 0.80 g of cyanuric acid, 1.00 g of melamine, and 0.14 g of iron acetylacetonate into a ball milling jar, and then add 5 mL of ethanol.

[0062] (2) Place the ball milling jar in step (1) into a ball mill and ball mill at 500 rpm for 3 h to obtain a precursor.

[0063] (3) Grind the precursor obtained in (2) into a powder to fill a porcelain boat, place it in a tube furnace, and heat it to 600 °C at a rate of 5 °C / min under an argon atmosphere and hold for 4 h. The obtained iron single-atom catalyst is denoted as FeN6 / CN.

[0064] Comparative Example 1

[0065] (1) Weigh 0.80 g of cyanuric acid and 1.00 g of melamine, and then add 5 mL of ethanol.

[0066] (2) Place the ball milling jar in step (1) into a ball mill and ball mill at 500 rpm for 3 h to obtain a precursor.

[0067] (3) Grind the precursor in (2) into a powder, fill a porcelain boat, place it in a tube furnace, and heat it to 600 °C at a rate of 5 °C / min under an argon atmosphere and hold for 4 h. The obtained catalyst is denoted as CN.

[0068] Comparative Example 2

[0069] (1) Weigh 0.5 g of anhydrous oxalic acid and add it to 125 mL of deionized water to dissolve and obtain an anhydrous oxalic acid solution; weigh 0.85 g of iron nitrate and add it to the anhydrous oxalic acid solution, and stir for 5 min to obtain an iron-oxalic acid complex solution;

[0070] (2) Weigh 1.95 g of cyanuric acid and 2.84 g of melamine respectively, add 450 mL of deionized water, and stir in a water bath at 70 °C for 20 min to obtain a cyanuric acid solution and a melamine solution respectively;

[0071] (3) Mix the iron-oxalic acid complex solution obtained in (1) with the cyanuric acid solution and the melamine solution in sequence. After stirring the obtained mixed solution for 4 h, filter, wash, and dry it to obtain a precursor;

[0072] (4) Grind the precursor described in (3) into powder, fill it into a porcelain boat, place it in a tubular furnace, and heat it to 600 °C at a rate of 5 °C / min under the protection of an argon atmosphere and keep it warm for 4 h. The obtained iron single-atom catalyst is denoted as FeN4 / CN.

[0073] Figure 1 and Figure 2 are the XRD patterns and FT-IR spectra of CN obtained in Comparative Example 1, FeN4 / CN obtained in Comparative Example 2, and FeN6 / CN obtained in Example 1 respectively. Figure 1 Two XRD diffraction peaks appear at 13.1° and 27.8°, corresponding to the diffraction characteristic peaks of the (100) and (002) crystal planes of graphitic carbon nitride respectively; Figure 2 In -1 , 1570 cm -1 , 1247 cm -1 and 1410 cm -1 Characteristic absorption peaks corresponding to the stretching vibration of C-N heterocycles and the aromatic stretching vibration mode appear, and it can be observed that all three samples have similar FTIR spectra, indicating that after introducing iron single atoms, the molecular structure of CN itself is not damaged. The above results show that the carriers of the FeN4 / CN and FeN6 / CN samples are CN, and iron single atoms are successfully loaded.

[0074] Figure 3 , Figure 4 and Figure 5 are the TEM image, element distribution map, and AC-HAADF-STEM image of FeN6 / CN obtained in Example 1 respectively; no Fe nanoparticles or clusters are observed from the transmission electron microscope and the spherical aberration electron microscope, and the element distribution map shows that Fe is uniformly distributed on CN.

[0075] Figure 6XANES diagram of FeN6 / CN obtained in Example 1. As shown in the figure, the near edge of FeN6 / CN is between FeO and Fe2O3 and infinitely close to Fe2O3, indicating that the valence state of Fe in FeN6 / CN is close to Fe 3+ . In addition, by fitting and analyzing the EXAFS of FeN6 / CN, it is obtained that Fe is coordinated with N and the coordination number is 6, thus confirming that the Fe single atom has a Fe-N6 coordination structure.

[0076] Figure 7 EPR spectra of FeN4 / CN obtained in Comparative Example 2 and FeN6 / CN obtained in Example 1. As shown in the figure, a signal peak is clearly observed at g = 2.003, which can be attributed to the N vacancy in FeN6 / CN and FeN4 / CN, while the signal at g = 4.292 belongs to the HS (high spin) Fe in FeN6 / CN Ⅲ . This proves that Fe in FeN4 / CN is only in the medium / low spin state, while Fe in FeN6 / CN is in the high spin state.

[0077] Figure 8 Degradation effect diagram of catalytic electro-Fenton degradation of 4-CP by CN obtained in Comparative Example 1, FeN4 / CN obtained in Comparative Example 2 and FeN6 / CN obtained in Example 1. As can be seen from the figure, compared with CN and FeN4 / CN, the effect of FeN6 / CN on catalytic electro-Fenton degradation of 4-CP has been significantly improved. In order to explore the active species in the FeN6 / CN electro-Fenton system, a radical quenching experiment was carried out (as Figure 9 shown). The results of the quenching experiment show that the addition of methanol has almost no effect on the degradation of 4-CP, the addition of superoxide dismutase and catalase both have a certain inhibitory effect, while the addition of furfuryl alcohol almost completely inhibits the degradation of 4-CP, so the active species in this system are ·O2 - and 1 O2.

[0078] To further confirm the uniqueness of 1 O2 in the FeN6 / CN electro-Fenton system, 9,10-dimethylanthracene (DMA) was used as 1 the Figure 10 O2 probe, and the fluorescence spectrum of the reaction solution obtained by catalytic electro-Fenton of FeN6 / CN obtained in Example 1 was obtained ( - ), where a is the control group, b is the fluorescence spectrum of the reaction solution obtained by quenching ·O2 - , and c is the fluorescence spectrum of the reaction solution obtained by quenching H2O2. As shown in the figure, in the case of quenching ·O2 1 and H2O2 respectively, the generation of 1 O2 is significantly inhibited, so 1 O2 is the only active species in this system, and ·O2- Both and H2O2 are intermediate products that reduce O2 to generate 1 O2.

[0079] Figure 11 and Figure 12 are respectively the diagrams of the influence of cations and anions and the diagrams of the influence of different pH values during the electro-Fenton degradation of 4-CP by FeN6 / CN obtained in Example 1; it can be seen from Figure 11 that FeN6 / CN electro-Fenton degradation of 4-CP has excellent resistance to interference by cations and anions. In a wide pH range (2-10), FeN6 / CN electro-Fenton shows good degradation effect on 4-CP ( Figure 12 ), indicating 1 the strong adaptability of O2 to pH.

[0080] The FeN6 / CN prepared in the present invention changes the spin state of Fe by increasing the coordination number, thereby highly selectively generating singlet oxygen in the electro-Fenton system to degrade persistent organic pollutants. Through qualitative and quantitative analysis of active substances, it is found that: FeN6 / CN electro-Fenton realizes the highly selective generation of 1 O2 active species, thus showing good efficiency, excellent resistance to interference by cations and anions, a wide pH tolerance range and good stability in the degradation of persistent organic pollutants.

[0081] On the premise of no conflict, those skilled in the art can freely combine and superimpose the above-mentioned additional technical features.

[0082] The above is only the preferred implementation mode of the present invention, and as long as the technical solutions that achieve the purpose of the present invention by basically the same means are within the protection scope of the present invention.

Claims

1. Application of a high-coordination iron single-atom catalyst for electro-Fenton high-selectivity generation of singlet oxygen, characterized in that: The high-coordination iron single-atom active sites in the high-coordination iron single-atom catalyst are loaded on graphitic carbon nitride in a six-coordination form, and the iron presents a high-spin state; the mass content of iron single atoms in the high-coordination iron single-atom catalyst is 2.49% - 12.88%; the contribution rate of singlet oxygen in the process of electro-Fenton degradation of pollutants by the high-coordination iron single-atom catalyst is close to 100%; The iron single atoms in the high-coordination iron single-atom catalyst have a six-coordination configuration and have a regulatory effect on the oxidation state and spin state of the metal center; Preparation method of the high-coordination iron single-atom catalyst, the preparation method includes the following steps: (1) Add cyanuric acid, melamine, and iron acetylacetonate to a ball milling jar according to a certain molar ratio, and then add an appropriate amount of alcohol organic matter; (2) Ball mill the ball milling jar in step (1) at an appropriate rotation speed and time to obtain a precursor; (3) Calcinate the precursor obtained in step (2) to obtain a high-coordination iron single-atom catalyst for electro-Fenton high-selectivity generation of singlet oxygen; The alcohol organic matter in step (1) includes one or both of methanol and ethanol; The molar ratio of cyanuric acid: melamine: iron acetylacetonate in step (1) is (0.4 - 0.9):(0.6 - 1.0):(0.025 - 0.1); The calcination temperature in step (3) is 550 - 850 °C, the time is 1 - 7 h, and the calcination is carried out under a protective atmosphere; The said application includes the following steps: Disperse the high-coordination iron single-atom catalyst for electro-Fenton high-selectivity generation of singlet oxygen in a naphthol-ethanol aqueous solution, drop-coat it on the surface of carbon paper, use it as a working electrode, and form a three-electrode system with a reference electrode and a counter electrode. Mix the electrolyte and the persistent organic pollutants to be treated, and apply a voltage under continuous oxygen supply for degradation.

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