Fe-monatomic-loaded modified carbon nitride and TiO2 nanowire compounded photoelectric-Fenton catalytic material as well as preparation method and application of Fe-monatomic-loaded modified carbon nitride and TiO2 nanowire compounded photoelectric-Fenton catalytic material

Abstract

The invention relates to the field of photocatalytic technology and emerging pollutant degradation, in particular to a photoelectric-Fenton catalytic material as well as a preparation method and application thereof. According to the photoelectric-Fenton catalytic material provided by the invention, the carbon material grown with the TiO2 nanowire array is taken as the substrate, and a heterojunction structure is constructed through loading of Fe monatomic on g-C3N4 and compounding of TiO2 nanowires, so that the synthesis process is simple, the cost is low, mass production can be realized, and the obtained photoelectric-Fenton catalytic material has a relatively large specific surface area; the visible light response range of g-C3N4 is enhanced by introducing Fe monatomic, carrier separation is facilitated by the heterojunction between TiO2 and g-C3N4, the degradation efficiency is high, and the stability is high. Meanwhile, the catalytic material can work under the condition that the pH value is 2-9, and the limitation that the pH value of an iron-based Fenton oxidation system is strictly required is overcome.

Description

Technical Field

[0001] The present invention relates to the field of photocatalytic technology and emerging pollutant degradation, and specifically relates to a photoelectric-Fenton catalytic material and a preparation method and application thereof. Background Art

[0002] Water pollution is one of the most significant environmental challenges facing modern society. With the acceleration of industrialization, the widespread use of agricultural chemicals, and the discharge of domestic wastewater, the types of pollutants in water bodies are increasing. Emerging pollutants, particularly those from antibiotics, pharmaceuticals, and personal care products, pose a significant threat to water resources. Traditional wastewater treatment methods, such as chemical precipitation, adsorption, and filtration, often suffer from poor treatment results and difficulty removing complex organic matter. Therefore, the development of novel, efficient pollutant degradation technologies is crucial.

[0003] In recent years, photocatalytic technology has garnered widespread attention in the water treatment sector due to its high efficiency, sustainability, and environmental friendliness. Advanced oxidation processes (AOPs) have also garnered significant attention in water pollution control. These technologies, with their strong sustainability and low operating costs, show significant promise in removing emerging pollutants from antibiotic-containing wastewater.

[0004] However, traditional photocatalytic and Fenton systems face bottlenecks such as difficult catalyst recovery, high carrier recombination rates, and low H₂O₂ utilization, severely restricting their practical application. Consequently, hybrid technologies based on photocatalysis and Fenton catalysis have emerged. By combining photogenerated electrons from photocatalysis with ·OH radicals generated by Fenton catalysis, these technologies overcome the limitations of the Fenton reaction in acidic environments while also improving photocatalytic efficiency and achieving enhanced pollutant degradation.

[0005] Although existing photocatalytic and Fenton catalytic technologies have made some progress in pollutant treatment, they still suffer from significant drawbacks, including low catalytic efficiency, high carrier recombination rates, difficulty in catalyst recovery, poor environmental adaptability, and high costs. These issues hinder the effective integration of photocatalysis and the Fenton reaction, hindering the development of photocatalytic-Fenton catalytic technologies. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a photoelectro-Fenton catalytic material and its preparation method and application. The photoelectro-Fenton catalytic material provided by the present invention has high photoelectro-Fenton catalytic degradation performance, convenient recycling, wide environmental adaptability, simple preparation method and low cost.

[0007] The present invention provides a photoelectric-Fenton catalytic material, comprising:

[0008] A carbon substrate provided with a TiO2 nanowire array;

[0009] The modified carbon nitride is deposited on the carbon substrate provided with the TiO2 nanowire array, wherein the modified carbon nitride comprises carbon nitride and Fe single atoms supported on the carbon nitride.

[0010] The carbon nitride in the modified carbon nitride described in the present invention is graphite phase carbon nitride (g-C3N4), an organic material composed of nitrogen and carbon elements, with a large specific surface area and abundant nitrogen atomic functional groups. The carbon nitride described in the present invention is specifically porous carbon nitride, more specifically supramolecular porous carbon nitride prepared by supramolecular self-assembly of melamine and cyanuric acid. The carbon nitride in the modified carbon nitride described in the present invention can absorb visible light and has good electronic conductivity, and can make the obtained modified carbon nitride have a porous structure, so that the modified carbon nitride has a larger specific surface area and more reactive sites, which can better undergo redox reactions with pollutants, thereby improving degradation efficiency.

[0011] The Fe single atom loaded on the carbon nitride of the present invention is anchored in the carbon nitride skeleton through a coordination bond. Unlike the Fe element in the form of particles, the atomic-level dispersion characteristics of the Fe single atom of the present invention not only enhance the adsorption of pollutant molecules, but also construct an electron transfer bridge from carbon nitride to titanium dioxide, thereby expanding the visible light response range of the photocatalytic material; not only enhances the material's absorption of visible light, but also the surface-loaded iron single atom acts as an efficient Fenton active site, which is driven by photogenerated electrons to achieve Fe 3+ / Fe 2+ Rapid cycling and continuous activation of H₂O₂ to produce ·OH radicals significantly improve catalytic efficiency, demonstrating high photoelectro-Fenton catalytic performance, particularly in the degradation of emerging pollutants such as antibiotic wastewater. The loading of Fe single atoms in the photoelectro-Fenton catalytic material described in the present invention is 0.2 mmol to 1 mmol.

[0012] In the carbon substrate provided with a TiO2 nanowire array described in the present invention, the carbon substrate is graphite felt or carbon cloth. The carbon substrate described in the present invention is used to support the growth of the TiO2 nanowire array, and is preferably graphite felt. The unique three-dimensional macroporous structure of graphite felt provides abundant active sites, greatly promoting the transmission and separation of photogenerated charges. The TiO2 nanowires described in the present invention are a titanium dioxide material with a one-dimensional structure. In the present invention, the TiO2 nanowire array is grown on the carbon substrate via a hydrothermal method, which improves the light response ability of the catalyst. Moreover, this nanowire array provides more electron transmission paths, which helps to improve the efficiency of the catalytic reaction.

[0013] The photoelectric-Fenton catalytic material provided by the present invention is a composite catalyst that combines photocatalysis and Fenton catalysis. It not only uses photogenerated electrons to drive the Fenton reaction to generate OH radicals for pollutant degradation, but also enhances the reaction efficiency under visible light irradiation. The photoelectric-Fenton catalytic material provided by the present invention uses a carbon material as a substrate and loads g-C3N4 with Fe single atoms, thereby enhancing the response range and absorption capacity of g-C3N4 to visible light, and also optimizing the transmission and reaction process of photogenerated electrons. In addition, the Fe single atoms are composited with TiO2 nanowire arrays grown on the carbon substrate, utilizing the photocatalytic properties of TiO2 nanowires. In addition, the heterojunction structure constructed by the loading of Fe single atoms on g-C3N4 and the composite of TiO2 nanowires in the present invention enables more effective separation of electrons and holes, reducing the recombination rate of carriers; the synergistic effect between Fe single atoms, carbon nitride and TiO2 not only enhances the migration efficiency of carriers, but also optimizes the stability of the catalyst, so that it can still maintain a high degradation efficiency during a long catalytic process.

[0014] In summary, the photoelectrocatalytic material provided by the present invention, in which single Fe atoms are combined with porous carbon nitride and TiO2 nanowires, enhances the photoelectrocatalytic activity of the catalyst, enabling it to operate effectively even at lower light intensities, thereby achieving efficient pollutant degradation. Furthermore, by combining modified carbon nitride with TiO2 nanowire arrays, the present invention also improves the mechanical strength and structural stability of the catalyst, thus avoiding the degradation and failure of traditional catalysts during use. Furthermore, the photoelectrocatalytic material provided by the present invention is capable of operating efficiently over a wider pH range (pH 2-9), breaking the pH dependence of traditional Fenton systems and overcoming the strict acidic environment requirements of traditional Fenton catalytic systems. This expands the catalyst's application range in various wastewater treatments and enhances its environmental adaptability. By optimizing the catalyst's design and structure, the photoelectrocatalytic material provided by the present invention can maintain high degradation efficiency in varying water qualities and acid-base environments. This characteristic makes the photoelectrocatalytic material of the present invention more adaptable and capable of meeting the treatment requirements of various wastewater types, especially demonstrating excellent performance in the degradation of antibiotic wastewater. The photoelectric-Fenton catalytic material particles provided by the present invention are stable, large, and easy to recycle and reuse, thus avoiding the recycling difficulties of traditional photocatalytic materials, reducing operating costs, and improving the reuse efficiency of the catalyst.

[0015] The present invention also provides a method for preparing the photoelectric-Fenton catalytic material described in any of the above technical solutions, comprising the following steps: depositing a carbon substrate provided with a TiO2 nanowire array in a modified carbon nitride solution to obtain a photoelectric-Fenton catalytic material.

[0016] The deposition methods described in the present invention specifically include electrophoretic deposition, solution immersion deposition, spray deposition, and chemical vapor deposition. Preferably, the present invention electrophoretically deposits a carbon substrate provided with a TiO2 nanowire array in an acetone solution of modified carbon nitride under the action of elemental iodine. Specifically, elemental iodine and modified carbon nitride are sonicated in acetone, and then the carbon substrate provided with the TiO2 nanowire array is electrophoretically deposited in the resulting solution. The resulting material is then cured in an oven to obtain a photoelectric-Fenton catalytic material. The ratio of elemental iodine, modified carbon nitride, and acetone used in the present invention is: (18-22) mg: (8-12) mg: (25-35) mL, preferably 20 mg: 10 mg: 30 mL. The sonication time in the present invention is 10 min to 20 min, preferably 15 min. The curing process described in the present invention helps to improve the stability of the composite structure and ensure a close bond between the modified carbon nitride and the TiO2 nanowires.

[0017] The modified carbon nitride of the present invention is prepared from carbon nitride and ferric acetylacetonate. Specifically, the modified carbon nitride of the present invention is prepared by the following method: carbon nitride and ferric acetylacetonate are ground, the material obtained after grinding is subjected to a first calcination, and then a second calcination is carried out after cooling to obtain modified carbon nitride. More specifically, carbon nitride and ferric acetylacetonate are ball-milled, the material obtained after ball milling is subjected to a first calcination, cooled to room temperature, and then a second calcination is carried out, and after cooling to room temperature, modified carbon nitride is obtained. In certain embodiments of the present invention, carbon nitride and ferric acetylacetonate are ball-milled to obtain a uniform orange mixture, and then the orange mixture is charged into a ceramic crucible and placed in a tubular furnace for a first calcination. After cooling to room temperature, the powder is collected, a second calcination is carried out, and after cooling to room temperature, a solid is collected to obtain modified carbon nitride. The first calcination of the present invention is specifically calcined at 550-650°C for 1.5-2.5 hours, preferably calcined at 600°C for 2 hours; the second calcination is specifically calcined at 550-650°C for 0.5-1.5 hours, preferably calcined at 600°C for 1 hour. The heating rates of the first calcination and the second calcination of the present invention are independently 4-6°C min -1 , preferably 5℃ min -1 The carbon nitride and iron acetylacetonate are used in a ratio of 2 g:(0.2-1) mmol, preferably 2 g:0.2 mmol, or 2 g:0.2 mmol, or 2 g:0.4 mmol, or 2 g:0.8 mmol, or 2 g:1 mmol. The secondary calcination further optimizes the loading state of the Fe single atoms, ensuring their uniform distribution and stable chemical bonding on the carbon nitride surface.

[0018] The carbon nitride used in the process of preparing the modified carbon nitride of the present invention is porous carbon nitride, which is prepared by supramolecular self-assembly of melamine and cyanuric acid. It is specifically prepared by the following method: melamine and cyanuric acid in a mass ratio of 1: (1 to 1.2) are stirred in a solvent for 10 h to 14 h, preferably 12 h, and then filtered to obtain a precipitate after standing. The precipitate is calcined at 500° C. to 550° C. for 3 h to 5 h to obtain porous carbon nitride. More specifically, melamine and cyanuric acid in a mass ratio of 1: (1 to 1.2) are stirred in a solvent for 10 to 14 hours to carry out a supramolecular self-assembly reaction, preferably for 12 hours to carry out a supramolecular self-assembly reaction to form a porous carbon nitride structure, and then the precipitate is filtered after standing to obtain a precipitate. After the precipitate is dried, it is calcined at 500°C to 550°C for 3 to 5 hours with a temperature increase gradient of 2°C / min to 3°C / min, preferably 2.5°C / min, to obtain porous carbon nitride. The calcination process helps to form a porous structure, increase the specific surface area, and thus increase the number of active sites of the catalyst. The final product is a porous carbon nitride with a rich pore structure and a high specific surface area, which provides a good foundation for subsequent loading and catalytic reactions.

[0019] The carbon substrate provided with a TiO2 nanowire array according to the present invention is prepared by a hydrothermal method. Specifically, the carbon substrate is placed in a mixed solution of concentrated hydrochloric acid, tetrabutyl titanate, and water and dried at 140°C to 160°C for 18 to 22 hours to obtain the carbon substrate provided with the TiO2 nanowire array. More specifically, tetrabutyl titanate is slowly added dropwise to the concentrated hydrochloric acid while stirring, followed by the addition of water and continued stirring. The carbon substrate is then placed in the resulting solution and dried at 140°C to 160°C for 18 to 22 hours, preferably at 150°C for 20 hours, to obtain the carbon substrate provided with the TiO2 nanowire array. The ratio of concentrated hydrochloric acid, tetrabutyl titanate, and water used in the present invention is: (8 to 12) mL: (0.22 to 0.28) mL: (8 to 12) mL, preferably: 10 mL: 0.25 mL: 10 mL. The carbon substrate according to the present invention is the same as described above and will not be further described. The water described in the present invention is preferably deionized water.

[0020] The photoelectro-Fenton catalyst material provided by the present invention has a simple and low-cost preparation method, and the catalyst does not cause environmental pollution during use. The raw materials used (such as carbon nitride and TiO2) are common and inexpensive, and the synthesis process does not require overly complex equipment or high operating costs. The photoelectro-Fenton catalyst prepared by the present invention is not only suitable for large-scale production but also has a long service life in practical applications, further reducing long-term operating costs.

[0021] The present invention also provides the use of the photoelectric-Fenton catalytic material described in any of the above technical solutions or the photoelectric-Fenton catalytic material obtained by the preparation method described in any of the above technical solutions in the preparation of an antibiotic wastewater degradation agent.

[0022] The present invention also provides a method for degrading antibiotic wastewater, comprising the following steps:

[0023] S1) adsorbing an antibiotic wastewater degradation agent in antibiotic wastewater in the absence of light to obtain dark-field adsorbed wastewater; the antibiotic wastewater degradation agent is the photoelectric-Fenton catalytic material described in any of the above technical solutions or the photoelectric-Fenton catalytic material obtained by the preparation method described in any of the above technical solutions;

[0024] S2) The dark field adsorption wastewater obtained in step S1) is illuminated.

[0025] The present invention first adsorbs an antibiotic wastewater degradation agent into antibiotic wastewater in the absence of light to produce dark-field adsorbed wastewater. The antibiotic wastewater concentration is 10 mg / L to 50 mg / L, and the dosage of the antibiotic wastewater degradation agent is 0.1 g / L to 1 g / L, preferably 0.2 g / L. The adsorption time is 50 to 70 minutes, preferably 60 minutes. The antibiotic wastewater is specifically norfloxacin wastewater.

[0026] Before adsorbing the antibiotic wastewater degradation agent in the antibiotic wastewater, the pH of the antibiotic wastewater must be adjusted to 2-9, preferably 3-9, and more preferably 3. The photoelectric-Fenton catalytic material of the present invention can maintain high-efficiency catalytic oxidation over a wide pH range of 2-9, breaking the limitation of traditional Fenton catalytic oxidation, which requires a pH of 3. The wastewater pH in the present invention can be adjusted using dilute hydrochloric acid and dilute sodium hydroxide.

[0027] After obtaining dark-field adsorption wastewater, the present invention exposes the obtained dark-field adsorption wastewater to light. Specifically, the dark-field adsorption wastewater is exposed to simulated sunlight with a 420nm filter to remove ultraviolet light, and subjected to a photo-Fenton reaction for 30 to 120 minutes, thereby completing the treatment of the antibiotic wastewater. In the photoelectrocatalytic system, the photoelectro-Fenton catalytic material of the present invention generates photogenerated electron-hole pairs under light. These photogenerated electrons can migrate to the cathode surface and participate in the oxygen reduction reaction, thereby generating hydrogen peroxide that participates in the Fenton reaction, directly oxidizing and generating OH free radicals to enhance the degradation of pollutants.

[0028] The present invention discloses a photoelectric-Fenton catalytic material, a preparation method thereof, and an application thereof. The photoelectric-Fenton catalytic material provided by the present invention is based on a carbon material with a TiO2 nanowire array as a substrate, and a heterojunction structure is constructed by loading Fe single atoms on g-C3N4 and compounding TiO2 nanowires. Not only is the synthesis process simple, low-cost, and mass-producible, but the obtained photoelectric-Fenton catalytic material has a large specific surface area and a large number of reaction active sites on its surface. The introduction of Fe single atoms enhances the visible light response range of g-C3N4, and the heterojunction between the two components of TiO2 and g-C3N4 facilitates carrier separation, resulting in high degradation efficiency and strong stability. At the same time, the catalytic material of the present invention can work under conditions of pH values ​​of 2 to 9, overcoming the strict pH value requirements of the iron-based Fenton oxidation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 XRD spectrum of a photoelectric-Fenton catalyst prepared in Examples 1 to 5 of the present invention, which is a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires;

[0030] Figure 2 SEM images of a photoelectric-Fenton catalyst prepared in Examples 1 to 5 of the present invention, which is a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires;

[0031] Figure 3 The infrared spectrum of a photoelectric-Fenton catalyst prepared in Examples 1 to 5 of the present invention, which is a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires;

[0032] Figure 4 Graph showing the degradation rate-time of norfloxacin under visible light by the five photoelectric-Fenton catalysts composited with modified carbon nitride and TiO2 nanowires with different loading rates prepared in Examples 1 to 5 of the present invention;

[0033] Figure 5 This is a graph showing the catalytic degradation of norfloxacin solution at different pH values ​​using a photoelectric-Fenton catalyst comprising a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires, prepared in Example 3 of the present invention;

[0034] Figure 6 This is a degradation cycle diagram of norfloxacin solution by a photoelectric-Fenton catalyst composed of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0035] The present invention discloses a photoelectric-Fenton catalytic material and its preparation method and application. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters for implementation. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0036] The present invention will be further described below with reference to the embodiments:

[0037] Example 1

[0038] 1.2612 g of melamine and 1.2907 g of cyanuric acid were dissolved in 60 mL of deionized water and stirred for 12 h. The sample was dried at 80 °C and calcined in a muffle furnace at 550 °C for 4 h with a temperature ramp of 2.3 °C / min. Powdered porous-CN was obtained. Supramolecular carbon nitride (2 g) was reacted with 0.2 mmol of iron acetylacetonate at 4000 r·min. -1 The mixture was ball-milled for 15 min to obtain a uniform orange mixture, which was then placed in a ceramic crucible and placed in a tubular furnace at 5 °C·min -1 The temperature was raised to 600 °C at a rate of 100 °C / min and kept at 600 °C for 2 h. After cooling to room temperature, the powder was collected and the -1 The reaction was then reheated to 600°C at a rate of 100°C and held at 600°C for 1 hour. After secondary pyrolysis and cooling to room temperature, the solid was collected and named 0.2-FeCN. 10mL of concentrated hydrochloric acid was poured into a 50mL reactor, and 0.25mL of tetrabutyl titanate was added dropwise. Then, 10mL of deionized water was added. After stirring for a period of time, a graphite felt was placed in the reactor and dried at 150°C for 20 hours. 20mg of elemental iodine and 10mg of 0.2-FeCN powder were poured into 30mL of acetone and sonicated for 15 minutes. The TiO2 nanoarrays grown on the graphite felt were placed in the solution and electrophoretically deposited. Finally, the sample was cured in an oven to obtain the 0.2-FeCNT photoelectric-Fenton catalyst.

[0039] Example 2

[0040] 1.2612 g of melamine and 1.2907 g of cyanuric acid were dissolved in 60 mL of deionized water and stirred for 12 h. The sample was dried at 80 °C and calcined in a muffle furnace at 550 °C for 4 h with a temperature ramp of 2.3 °C / min. Powdered porous-CN was obtained. Supramolecular carbon nitride (2 g) was reacted with 0.4 mmol of iron acetylacetonate at 4000 r·min. -1The mixture was ball-milled for 15 min to obtain a homogeneous orange mixture, which was then placed in a ceramic crucible and placed in a tubular furnace at 5 °C·min -1 The temperature was raised to 600 °C at a rate of 100 °C / min and kept at 600 °C for 2 h. After cooling to room temperature, the powder was collected and the -1 The reaction was then reheated to 600°C at a rate of 100°C and held at 600°C for 1 hour. After secondary pyrolysis and cooling to room temperature, the solid was collected and named 0.4-FeCN. 10mL of concentrated hydrochloric acid was poured into a 50mL reactor, and 0.25mL of tetrabutyl titanate was added dropwise. Then, 10mL of deionized water was added. After stirring for a period of time, a graphite felt was placed in the reactor and dried at 150°C for 20 hours. 20mg of elemental iodine and 10mg of 0.4-FeCN powder were poured into 30mL of acetone and sonicated for 15 minutes. The TiO2 nanoarrays grown on the graphite felt were placed in the solution and electrophoretically deposited. Finally, the sample was cured in an oven to obtain the 0.4-FeCNT photoelectric-Fenton catalyst.

[0041] Example 3

[0042] 1.2612 g of melamine and 1.2907 g of cyanuric acid were dissolved in 60 mL of deionized water and stirred for 12 h. The sample was dried at 80 °C and calcined in a muffle furnace at 550 °C for 4 h with a temperature ramp of 2.3 °C / min. Powdered porous-CN was obtained. Supramolecular carbon nitride (2 g) was reacted with 0.6 mmol of iron acetylacetonate at 4000 r·min. -1 The mixture was ball-milled for 15 min to obtain a homogeneous orange mixture, which was then placed in a ceramic crucible and placed in a tubular furnace at 5 °C·min -1 The temperature was raised to 600 °C at a rate of 100 °C / min and kept at 600 °C for 2 h. After cooling to room temperature, the powder was collected and the -1 The reaction was then reheated to 600°C at a rate of 100°C and held at 600°C for 1 hour. After secondary pyrolysis and cooling to room temperature, the solid was collected and named 0.6-FeCN. 10mL of concentrated hydrochloric acid was poured into a 50mL reactor, and 0.25mL of tetrabutyl titanate was added dropwise. Then, 10mL of deionized water was added. After stirring for a period of time, a graphite felt was placed in the reactor and dried at 150°C for 20 hours. 20mg of elemental iodine and 10mg of 0.6-FeCN powder were poured into 30mL of acetone and sonicated for 15 minutes. The TiO2 nanoarrays grown on the graphite felt were placed in the solution and electrophoretically deposited. Finally, the sample was cured in an oven to obtain the 0.6-FeCNT photoelectric-Fenton catalyst.

[0043] Example 4

[0044] 1.2612 g of melamine and 1.2907 g of cyanuric acid were dissolved in 60 mL of deionized water and stirred for 12 h. The sample was dried at 80 °C and calcined in a muffle furnace at 550 °C for 4 h with a temperature ramp of 2.3 °C / min. Powdered porous-CN was obtained. Supramolecular carbon nitride (2 g) was reacted with 0.8 mmol of iron acetylacetonate at 4000 r·min. -1 The mixture was ball-milled for 15 min to obtain a homogeneous orange mixture, which was then placed in a ceramic crucible and placed in a tubular furnace at 5 °C·min -1 The temperature was raised to 600 °C at a rate of 100 °C / min and kept at 600 °C for 2 h. After cooling to room temperature, the powder was collected and the precipitate was heated at a rate of 10 °C / min. -1 The reaction was then reheated to 600°C at a rate of 100°C and held at 600°C for 1 hour. After secondary pyrolysis and cooling to room temperature, the solid was collected and named 0.8-FeCN. 10mL of concentrated hydrochloric acid was poured into a 50mL reactor, and 0.25mL of tetrabutyl titanate was added dropwise. Then, 10mL of deionized water was added. After stirring for a period of time, a graphite felt was placed in the reactor and dried at 150°C for 20 hours. 20mg of elemental iodine and 10mg of 0.8-FeCN powder were poured into 30mL of acetone and sonicated for 15 minutes. The TiO2 nanoarrays grown on the graphite felt were then placed in the solution for electrophoretic deposition. Finally, the sample was cured in an oven to yield the 0.8-FeCNT photoelectric-Fenton catalyst.

[0045] Example 5

[0046] 1.2612 g of melamine and 1.2907 g of cyanuric acid were dissolved in 60 mL of deionized water and stirred for 12 h. The sample was dried at 80 °C and calcined in a muffle furnace at 550 °C for 4 h with a temperature ramp of 2.3 °C / min. Powdered porous-CN was obtained. Supramolecular carbon nitride (2 g) was reacted with 1 mmol of iron acetylacetonate at 4000 r·min. -1 The mixture was ball-milled for 15 min to obtain a homogeneous orange mixture, which was then placed in a ceramic crucible and placed in a tubular furnace at 5 °C·min -1 The temperature was raised to 600 °C at a rate of 100 °C / min and kept at 600 °C for 2 h. After cooling to room temperature, the powder was collected and the precipitate was heated at a rate of 10 °C / min. -1The reaction was then reheated to 600°C at a rate of 100°C and held at 600°C for 1 hour. After secondary pyrolysis and cooling to room temperature, the solid was collected and named 1-FeCN. 10mL of concentrated hydrochloric acid was poured into a 50mL reactor, and 0.25mL of tetrabutyl titanate was added dropwise. Then, 10mL of deionized water was added. After stirring for a period of time, a graphite felt was placed in the reactor and dried at 150°C for 20 hours. 20mg of elemental iodine and 10mg of 1-FeCN powder were poured into 30mL of acetone and sonicated for 15 minutes. The TiO2 nanoarrays grown on the graphite felt were then placed in the solution for electrophoretic deposition. Finally, the sample was cured in an oven to yield the 1-FeCNT photoelectric-Fenton catalyst.

[0047] Example 6

[0048] The catalyst prepared by the present invention was subjected to XRD detection, and the results were as follows: Figure 1 As shown, Figure 1 The XRD spectrum of a photoelectric-Fenton catalyst prepared in Examples 1 to 5 of the present invention, which is a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires. Figure 1 As shown in the figure, pure g-C3N4 has characteristic peaks at 2θ=13.1° and 27.3°, corresponding to the (100) crystal plane and (002) crystal plane of carbon nitride, respectively, confirming the successful preparation of high-crystallinity graphite phase carbon nitride. The TiO2 nanowires grown on the base carbon cloth have characteristic peaks at positions such as 27.45° and 36.0°, which are attributed to the (110) and (101) crystal planes of the rutile phase, indicating that the TiO2 nanowire array has high phase purity and preferential orientation growth characteristics. By comparing the XRD spectra of composite materials with different Fe doping amounts, it was found that with the increase of Fe loading, the (002) crystal plane diffraction peak of g-C3N4 shifted to the high-angle direction by about 0.2°, inferring that Fe 3+ The difference in the radius of the C / N atoms in the g-C3N4 framework triggers lattice distortion, resulting in a contraction of the interlayer spacing and local distortion of the conjugated structure. Notably, the absence of characteristic peaks of metallic Fe in the XRD spectrum suggests that Fe-Nx coordination structures with nitrogen atoms may form efficient charge carrier transport pathways for the photoelectrocatalytic-Fenton synergistic degradation process.

[0049] The catalyst prepared by the present invention was photographed by SEM, and the results are as follows: Figure 2 As shown, Figure 2 This is an SEM image of a photoelectric-Fenton catalyst prepared in Examples 1 to 5 of the present invention, which is a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires. Figure 2Figures (a), (b), and (c) show the vertical alignment of TiO2 nanowires in the 0.6-FeCNT composite on a carbon cloth substrate, uniformly coated with ultrathin g-C3N4 nanosheets, forming a unique hierarchical "nanowire-nanosheet" heterostructure. Figure (d) shows that the nanosheets in the 0.6-FeCN sample alone exhibit slight stacking, but the porous structure remains intact, indicating that Fe doping does not significantly disrupt the three-dimensional network induced by the supramolecular template. Figure (e) shows that the untreated bulk g-C3N4 exhibits a dense layered structure with a thickness of approximately 3-8 μm, a smooth surface, and sharp edges. This dense structure severely hinders active site exposure and mass transfer kinetics. Figure (f) shows that after supramolecular template treatment, the g-C3N4 is transformed into a three-dimensional interconnected honeycomb porous network with uniform pore size distribution and significantly increased specific surface area, providing abundant edge defect sites for subsequent Fe single-atom anchoring.

[0050] The catalyst prepared by the present invention was subjected to infrared detection, and the results were as follows: Figure 3 As shown, Figure 3 The infrared spectrum of a photoelectric-Fenton catalyst prepared in Examples 1 to 5 of the present invention, which is a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires. Figure 3 As shown, pure g-C3N4 has a peak at 808 cm -1 The sharp peak at 1200-1600 cm originates from the out-of-plane bending vibration of the triazine ring structure. This characteristic peak is still clearly visible in the composite material, indicating that the heterogeneous interface does not destroy the intrinsic structure of g-C3N4. -1 The multiple absorption bands appearing in the range of 3300-3400 cm correspond to the stretching vibration of CN heterocycle and C=N conjugated structure, which confirms that the highly conjugated aromatic skeleton of g-C3N4 is retained after the complexation. -1 The broad peak region at 3350 cm was identified by peak fitting. -1 NH vibration at 3440 cm -1 The OH vibration at indicates that there are abundant hydrophilic groups on the surface of the composite material, which is beneficial to the adsorption and enrichment of antibiotic molecules at the solid-liquid interface.

[0051] In order to obtain the degradation effect of a photoelectric-Fenton catalyst prepared in accordance with an embodiment of the present invention, which is a composite of a modified carbon nitride loaded with a single Fe atom and a TiO2 nanowire, on treating antibiotics in water, the following series of experiments were conducted on the photoelectric-Fenton catalyst prepared in accordance with an embodiment of the present invention, which is a composite of a modified carbon nitride loaded with a single Fe atom and a TiO2 nanowire:

[0052] Photoelectric-Fenton degradation test: Prepare 100 mL of a 20 mg / L norfloxacin solution. Weigh 10 mg of each of the photoelectric-Fenton catalysts prepared in Implementation Regulations 1-5, comprising a composite of Fe-supported modified carbon nitride and TiO2 nanowires. Add the catalysts to the norfloxacin solution and place in the reaction apparatus.

[0053] Dark field adsorption was carried out under lightless conditions to reach adsorption equilibrium. The dark field adsorption time was 60 min. After the dark field adsorption was completed, the experimental xenon lamp was turned on, and the ultraviolet light part was removed with a 420 nm filter. The reaction was allowed to proceed with continuous stirring for 120 min. Samples were extracted every 30 min, with a volume of 2 mL. The samples were centrifuged and the supernatant was measured for its absorbance using an ultraviolet spectrophotometer. The formula X = (C0-C) / C0×100% was used, where X is the degradation rate of norfloxacin, C0 is the initial concentration of norfloxacin, and C is the concentration of norfloxacin after degradation.

[0054] Photoelectric-Fenton degradation assay: Prepare 100 mL of a 20 mg / L norfloxacin solution and weigh 10 mg of the 0.6-FCNT photoelectric-Fenton catalyst prepared in Implementation 3. Adjust the norfloxacin solution to a pH of 1, 3, 5, 7, and 9. Then, add the catalyst to the norfloxacin solution in sequence and place it in the reactor.

[0055] Figure 4 This is a graph showing the degradation rate-time of norfloxacin under visible light by the five photoelectric-Fenton catalysts composited with modified carbon nitride and TiO2 nanowires with different Fe single-atom loading rates prepared in Examples 1 to 5 of the present invention; Figure 5 This is a diagram showing the catalytic degradation of norfloxacin solution at different pH values ​​by a photoelectric-Fenton catalyst comprising a composite of modified carbon nitride loaded with Fe single atoms and TiO2 nanowires prepared in Example 3 of the present invention. Figure 4 The photocatalytic degradation performance of g-C3N4 photoelectrocatalytic materials with varying loadings of Fe single atoms was demonstrated. 0.6-FCNT exhibited the strongest norfloxacin degradation, achieving approximately 91% degradation within 120 minutes, effectively enhancing the photocatalytic degradation performance of pure g-C3N4. The 0.6-FCNT loading achieved the optimal loading, resulting in a uniform distribution of Fe single atoms on the carbon nitride, which resulted in a strong photoresponsiveness of the g-C3N4 nanosheets and promoted the generation and migration of photogenerated electrons.

[0056] Figure 6 This is a degradation cycle diagram of norfloxacin solution by a photoelectric-Fenton catalyst composed of a modified carbon nitride loaded with Fe single atoms and TiO2 nanowires prepared in Example 3 of the present invention. Figure 6As shown in Figure 2, after five consecutive test cycles, the treatment efficiency of the 0.6-FeCNT composite electrode for the target pollutants remained stable, which proves that the material can maintain its structural integrity during long-term operation and shows good practical application performance.

[0057] In summary, the present invention achieves a composite material with enhanced photoelectro-Fenton catalytic activity by controlling the amount of Fe atoms added. The Fe-atom-loaded g-C3N4 photoelectro-Fenton catalytic material exhibits excellent adsorption and decomposition of H2O2. The hydrothermal reaction temperature required by the present invention is only 170-180°C, resulting in low energy consumption. Furthermore, the reagents used in the preparation process, such as water, ethanol, and chloride, are readily available and environmentally friendly.

[0058] Experiments have shown that 0.6-FeCNT can effectively decompose 91% of norfloxacin after being irradiated with visible light, and its treatment effect is significantly better than traditional photocatalytic technology. This excellent catalytic activity is due to the fact that single iron atoms are anchored in the carbon nitride skeleton through coordination bonds. Its atomic-level dispersion characteristics not only enhance the adsorption of pollutant molecules, but also build an electron transfer bridge from carbon nitride to titanium dioxide. At the same time, the surface-loaded single iron atoms act as efficient Fenton active sites, which are driven by photogenerated electrons to achieve Fe 3+ / Fe 2+ Rapid circulation continuously activates H2O2 to produce OH free radicals; finally, the heterojunction constructed by carbon nitride and titanium dioxide forms a built-in electric field, which prompts the photogenerated electrons to migrate to titanium dioxide and the holes to enrich in carbon nitride, thereby improving the separation efficiency of photogenerated electrons and achieving efficient degradation of pollutants.

[0059] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A photoelectric-Fenton catalytic material, characterized in that: include: A carbon substrate provided with a TiO2 nanowire array; The modified carbon nitride is deposited on the carbon substrate provided with the TiO2 nanowire array, wherein the modified carbon nitride comprises carbon nitride and Fe single atoms supported on the carbon nitride.

2. The photoelectric-Fenton catalytic material according to claim 1, characterized in that The loading amount of the Fe single atom in the photoelectric-Fenton catalytic material is 0.2 mmol~1 mmol.

3. The photoelectric-Fenton catalytic material according to claim 1, characterized in that The carbon nitride is porous carbon nitride; The carbon substrate is graphite felt or carbon cloth.

4. The method for preparing the photoelectric-Fenton catalytic material according to any one of claims 1 to 3, characterized in that: The following steps are involved: A carbon substrate provided with a TiO2 nanowire array is deposited in a modified carbon nitride solution to obtain a photoelectric-Fenton catalytic material.

5. The method for preparing the photoelectric-Fenton catalytic material according to claim 4, characterized in that: The specific steps include: The carbon substrate provided with the TiO2 nanowire array is electrophoretically deposited in an acetone solution of modified carbon nitride under the action of elemental iodine to obtain a photoelectric-Fenton catalytic material; The usage ratio of the iodine element, modified carbon nitride, and acetone is: (18-22) mg: (8-12) mg: (25-35) mL.

6. The method for preparing the photoelectric-Fenton catalytic material according to claim 4, characterized in that: The modified carbon nitride is prepared from carbon nitride and iron acetylacetonate, and the usage ratio of the carbon nitride and iron acetylacetonate is 2 g: (0.2-1) mmol.

7. The method for preparing the photoelectric-Fenton catalytic material according to claim 4, characterized in that: The modified carbon nitride is prepared by the following method: The carbon nitride and ferric acetylacetonate are ground, and the ground material is calcined at 550-650° C. for 1.5-2.5 hours. After cooling, the material is further calcined at 550-650° C. for 0.5-1.5 hours to obtain modified carbon nitride.

8. Use of the photoelectric-Fenton catalytic material according to any one of claims 1 to 3 or the photoelectric-Fenton catalytic material obtained by the preparation method according to any one of claims 4 to 7 in the preparation of an antibiotic wastewater degradation agent.

9. A method for degrading antibiotic wastewater, characterized in that: The following steps are involved: S1) adsorbing an antibiotic wastewater degradation agent in antibiotic wastewater in the absence of light to obtain dark-field adsorbed wastewater; the antibiotic wastewater degradation agent is the photoelectric-Fenton catalytic material according to any one of claims 1 to 3 or the photoelectric-Fenton catalytic material prepared by the method according to any one of claims 4 to 7; S2) The dark field adsorption wastewater obtained in step S1) is illuminated.

10. The method for degrading antibiotic wastewater according to claim 9, characterized in that: In step S1), the pH of the antibiotic wastewater is 2-9.

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