Catalyst of oxygen vacancy defect carbon nitride anchored iron atom cluster as well as preparation method and application of catalyst

Abstract

The invention provides an oxygen vacancy defect carbon nitride anchored iron atom cluster catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts. Iron atoms are anchored in a carbon nitride (Ov-C3N4) structure containing oxygen vacancy defects in a cluster form, and Fe-Ov-C defect bonds are formed between the oxygen vacancy defects in C3N4 and iron atom clusters to stabilize the iron atom clusters, so that the problem of thermodynamic instability of the catalyst is solved while higher atom utilization efficiency is obtained; the Fe-Ov-C defect bond atoms can reasonably regulate and control the electronic structure of the center of an iron cluster d band, so that the catalytic activity and the cycling stability are greatly enhanced; besides, iron atom clusters and persulfate act to cause O-O bond breakage, non-free radical singlet oxygen is formed, and the problem that the catalytic efficiency is sharply reduced due to free radical annihilation in a complex water environment can be effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a catalyst of oxygen vacancy defect carbon nitride anchoring iron atom clusters and a preparation method and application thereof. BACKGROUND

[0002] The advanced oxidation technology based on persulfate (PMS) has attracted extensive attention due to its strong oxidation ability, low energy consumption and mild reaction conditions. The high activity free radicals (hydroxyl radicals, superoxide radicals, etc.) generated in the reaction process of the advanced oxidation system can efficiently mineralize antibiotic molecules, and thus are highly concerned. However, the free radicals inevitably react with coexisting organic matter and inorganic substrates in the water environment and are annihilated, which limits their application in the actual repair of antibiotic wastewater pollution. Therefore, it is a difficult problem to be solved to develop efficient and stable PMS catalysts and to strengthen the non-free radical of the advanced oxidation system. The iron-based single-atom catalyst is concerned in the field of catalysis due to its high intrinsic catalytic activity and high metal atom utilization rate. However, the thermodynamic instability of the iron-based single-atom catalyst in the catalytic application is a key problem to be solved for its wide application.

[0003] In the past decade, a large amount of effort has been devoted to developing various physical and chemical methods to suppress the sintering of metal nanoclusters at high temperatures. The most commonly used method is to carefully control the spatial arrangement of metals and supports at the nanoscale to build physical barriers against sintering. For example, in the prior art, metal nanoclusters are filled into the pores of mesoporous silica and carbon supports to maximize the interparticle distance, or metal nanoclusters are encapsulated with porous nanoshells such as zeolites and metal oxides. Although these methods are effective in theory, they can lead to a decrease in active surface area and an increase in mass transfer resistance, thereby significantly reducing the overall performance of the catalyst. SUMMARY

[0004] The present application aims to provide a catalyst of oxygen vacancy defect carbon nitride anchoring iron atom clusters and a preparation method and application thereof. The catalyst of oxygen vacancy defect carbon nitride anchoring iron atom clusters prepared by the method provided by the present application has high efficient degradation and mineralization capacity for various antibiotics and can maintain high activity after multiple cycles, solving the problem of thermodynamic instability of the iron-based single-atom catalyst. The catalyst relies on a non-free radical (singlet oxygen) based oxidation path, and the decline in catalytic efficiency is significantly smaller than that of a traditional system relying on free radicals, thereby solving the two key problems of easy quenching of free radicals and poor stability of iron-based catalysts in PMS advanced oxidation.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The application provides a preparation method of an oxygen vacancy defect carbon nitride anchored iron atom cluster catalyst, characterized by comprising the following steps:

[0007] After the urea solution is preheated, the glucose iron is added, and stirring treatment is performed under heating and oxygenation conditions; and then, the solid is obtained through drying.

[0008] The solid is subjected to heat treatment to obtain the oxygen vacancy defect carbon nitride anchored iron atom cluster catalyst.

[0009] Preferably, the concentration of urea in the urea solution is 800-1200 g·L -1 .

[0010] Preferably, the temperature of the heating is 55-65 ℃, and the oxygen flow rate under the oxygenation condition is 36-45 mL / min.

[0011] Preferably, the stirring treatment is performed for 100-150 min, and the stirring treatment is performed once every 4-6 min.

[0012] Preferably, the drying is performed at 55-65 ℃ until the water is completely evaporated.

[0013] Preferably, the heat treatment is performed in the following manner: heating to 380-430 ℃ at a temperature rising rate of 4 ℃·min -1 and keeping for 50-80 min, and then heating to 520-580 ℃ at a temperature rising rate of 5 ℃·min -1 and keeping for 160-200 min.

[0014] Preferably, the heat treatment is performed in the following manner: heating to 400 ℃ at a temperature rising rate of 4 ℃·min -1 and keeping for 60 min, and then heating to 550 ℃ at a temperature rising rate of 5 ℃·min -1 and keeping for 180 min.

[0015] Preferably, after the heat treatment is completed, the product of the heat treatment is further ground to obtain the oxygen vacancy defect carbon nitride anchored iron atom cluster catalyst.

[0016] The application further provides an oxygen vacancy defect carbon nitride anchored iron atom cluster catalyst prepared by the preparation method.

[0017] The application also provides an application of the catalyst of the oxygen vacancy defect carbon nitride anchoring iron atom cluster in degrading organic matters in water.

[0018] The application provides a preparation method of a catalyst of an oxygen vacancy defect carbon nitride anchoring iron atom cluster (referred to as Fe-ACs / Ov-C3N4). Under the conditions of heating and stirring, the urea condensation reaction is accelerated to form a prepolymer, meanwhile, glucose is decomposed to release iron ions, and the iron ions are coordinated with nitrogen-containing groups (such as amino groups or imino groups) derived from urea to form iron-nitrogen complexes. The coordination helps the uniform dispersion of iron atoms in the solution and prevents the aggregation. Under the condition of oxygen charging, the oxygen acts as an oxidant, and the main effects include: oxidizing the glucose ligand to generate gluconic acid and thus releasing iron ions; part of the oxygen may react with the urea derivatives or iron ions to introduce oxygen-containing functional groups (such as C=O or -COOH) into the C3N4 precursor, and the functional groups will become precursors of oxygen vacancies in the subsequent heat treatment. The oxygen can also maintain the oxidation state (Fe 3+ ) of the iron ions and avoid premature reduction to metallic iron, ensuring that the iron is dispersed in the form of ions. After 120 minutes of reaction, a transparent mixed solution is obtained, indicating that the iron ions have been fully dispersed in the urea matrix to form a homogeneous system. Vacuum drying is performed to remove water, and the mixed solution is converted into an orange solid. In this process, the urea prepolymer and the iron-nitrogen complex are further condensed to form an amorphous solid. The iron atoms are still fixed in the carbon nitride precursor network through coordination bonds and remain in a dispersed state; in the heat treatment process, the complete pyrolysis of urea is promoted in the first stage to release NH3, CO2 and other gases, and the basic framework of g-C3N4 is formed. At this time, the C3N4 is a porous structure containing a large number of nitrogen vacancies and defects, the iron ions are coordinated with the nitrogen atoms in the C3N4 to form Fe-N bonds, and part of the iron may be reduced to a low valence state (such as Fe 2+), oxygen-containing functional groups (from oxygenated conditions) begin to decompose, and some oxygen atoms escape in the form of CO or CO2, initially forming oxygen vacancies (Ov), but these vacancies are not stable; in the second stage, the C3N4 structure is further condensed and graphitized, improving crystallinity, while nitrogen vacancies decrease, but oxygen vacancies are stabilized. High temperature causes more oxygen-containing species to desorb, resulting in an increase in oxygen vacancy concentration; iron atom migration: at high temperatures, iron atoms gain enough kinetic energy to migrate on the surface of C3N4; oxygen vacancies, as high-energy sites, capture iron atoms and allow them to nucleate and grow, forming iron clusters (Fe-ACs); the size of the clusters is controlled by iron loading and heat treatment conditions; anchoring mechanism: oxygen vacancies form local electronic defects in the C3N4 skeleton, and strong electronic interactions (such as charge transfer) occur between the oxygen vacancies and the iron clusters, stabilizing the clusters. This anchoring prevents iron clusters from sintering or aggregating at high temperatures, maintaining high dispersity. The catalyst stabilizes and anchors Fe atoms in the form of clusters on the C3N4 structure through oxygen vacancy defects, forming a unique Fe-Ov-C bonding structure between iron atom clusters and oxygen vacancy defects; using Ov in C3N4 as a strong anchoring site, Fe atoms are fixed in the form of small-sized clusters (rather than isolated single atoms); the formation of this Fe-Ov-C bond is a key mechanism for stabilizing iron species and preventing their migration and aggregation during the reaction (i.e., addressing thermodynamic instability); the Fe-Ov-C bonding structure can effectively regulate the electronic structure of the d-band center of the iron cluster, optimizing its adsorption and activation ability for PMS molecules, thereby significantly improving catalytic activity; when the catalyst activates PMS, it induces the breaking of the O-O bond to generate non-radical active species such as singlet oxygen (O2). 1 O2). Singlet oxygen has a long lifetime and low selectivity for interfering substances in complex aqueous matrices, effectively avoiding the rapid annihilation of free radicals in coexisting substances in the water environment, significantly improving its actual catalytic efficiency in complex antibiotic wastewater; and iron exists in the form of clusters, maintaining a high metal atom utilization rate; at the same time, the strong Fe-Ov-C bond and cluster structure endow the catalyst with excellent cycle stability.

[0019] The Fe-ACs / Ov-C3N4 prepared by the present application has high degradation and mineralization ability for various antibiotics (such as tetracyclines, sulfonamides, quinolones, etc.), benefiting from the strong anchoring effect of the Fe-Ov-C bond; the catalyst can still maintain high activity after multiple cycles, solving the problem of thermodynamic instability of iron-based single-atom catalysts; the catalyst prepared by the present application relies on a non-radical (singlet oxygen) dominated oxidation pathway, and can effectively degrade and mineralize various antibiotics in the presence of high concentrations of natural organic matter (NOM) and inorganic anions (such as Cl - , HCO3 - , NO3 -The catalyst provided by the application has a significantly smaller decline in catalytic efficiency than traditional free radical-dependent systems in actual water bodies or simulated wastewater, and simultaneously solves the two key problems of easy quenching of free radicals and poor stability of iron-based catalysts in PMS advanced oxidation. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 XRD patterns of the catalyst Fe-ACs / Ov-C3N4-10 and Ov-C3N4 of the oxygen vacancy defect carbon nitride anchoring iron atom cluster prepared in Example 5 of the application;

[0021] Figure 2 FT-IR patterns of the catalyst Fe-ACs / Ov-C3N4-10 and Ov-C3N4 of the oxygen vacancy defect carbon nitride anchoring iron atom cluster prepared in Example 5 of the application;

[0022] Figure 3 SEM, TEM, HTEM and Fe atomic energy spectrum of the catalyst Fe-ACs / Ov-C3N4-10 of the oxygen vacancy defect carbon nitride anchoring iron atom cluster prepared in Example 5 of the application, wherein, Figure 3 (a) is the SEM pattern, Figure 3 (b) is the TEM pattern, Figure 3 (c) is the HTEM pattern, Figure 3 (d) is the Fe atomic energy spectrum;

[0023] Figure 4 Degradation efficiency fold line chart of norfloxacin in different PDS groups, Vis groups, FeCl3 groups, PDS / Vis groups, Fe-ACs / PDS groups and Fe-ACs / PDS / Vis groups in the application;

[0024] Figure 5 Degradation efficiency fold line chart of norfloxacin in different environmental media by the catalyst Fe-ACs / Ov-C3N4-1 in Example 1 of the application, wherein Figure 5 (a) is under different pH conditions, Figure 5 (b) is under different Cl - concentrations, Figure 5 (c) is under different temperatures, Figure 5 (d) is under different SO4 2- concentrations, Figure 5 (e) is under different NO 3- concentrations, Figure 5 (f) is under different humic acid concentrations. DETAILED DESCRIPTION

[0025] The application provides a preparation method of an oxygen vacancy defect carbon nitride anchoring iron atom cluster catalyst, characterized by comprising the following steps:

[0026] After the urea solution is preheated, glucose iron is added, and stirring treatment is carried out under heating and oxygenation conditions, and after drying, a solid is obtained;

[0027] The solid is subjected to heat treatment to obtain a catalyst of oxygen vacancy defect carbon nitride anchored iron atom cluster.

[0028] In the present application, unless otherwise specified, the raw materials used are all conventional commercially available products in the art.

[0029] In the present application, the concentration of urea in the urea solution is preferably 800-1200 g·L -1 , more preferably 900-1100 g·L -1 . The present application controls the concentration of urea in the urea solution in the above range to avoid too low concentration, sparse precursor network, small amount of gas generated, small specific surface area of g-C3N4 obtained, dense structure, easy agglomeration of iron species, resulting in few active sites of the catalyst, poor mass transfer, and low activity, while avoiding too high concentration, which may result in too viscous solution, difficult to handle (such as difficult to stir), and too violent gas release during pyrolysis, sometimes even damaging the integrity of the structure, forming too much disordered carbon, affecting the crystallinity of g-C3N4 and intrinsic semiconductor properties. Therefore, the preferred concentration range of the present application can maximize the use of urea pyrolysis to build an ideal catalyst support structure with high specific surface area, porosity, and stable anchoring of ultra-small iron clusters, thereby comprehensively improving the comprehensive performance of Fe-ACs / Ov-C3N4 catalyst. In the present application, the preheating method is preferably heating to 55-65℃ under stirring conditions.

[0030] In the present application, the heating temperature is preferably 55-65℃, more preferably 58-63℃. The present application controls the heating temperature in the above range to accelerate the urea condensation reaction and form a prepolymer, while the glucose iron is decomposed to release iron ions, which are coordinated with nitrogen-containing groups (such as amino or imino) derived from urea to form iron-nitrogen complexes. This coordination helps to uniformly disperse iron atoms in the solution and prevent aggregation. In the present application, the oxygen flow rate under the oxygenation condition is preferably 36-45 mL / min, more preferably 36-45 mL / min. The present application controls the oxygen flow rate under the oxygenation condition in the above range to use oxygen as an oxidizing agent to oxidize the glucose ligand to generate gluconic acid, thereby releasing iron ions. Part of the oxygen may react with urea derivatives or iron ions to introduce oxygen-containing functional groups (such as C=O or -COOH) into the C3N4 precursor. These functional groups will become precursors of oxygen vacancies in subsequent heat treatment. Oxygen can also maintain the oxidation state of iron ions (Fe 3+), avoid premature reduction to metallic iron, ensure iron dispersed in ionic form, form a homogeneous system. In the present application, the stirring treatment time is 100-150 min; the stirring treatment frequency is preferably once every 4-6 min, more preferably once every 5 min. The present application controls the stirring frequency in the above range to ensure that iron atoms are sufficiently dispersed to form a homogeneous system.

[0031] In the present application, the drying method is preferably drying at 55-65 ℃ until the water is completely evaporated.

[0032] In the present application, the heat treatment method is preferably: heating to 380-430 ℃ at a heating rate of 4 ℃·min -1 and holding for 50-80 min (i.e. first stage), and then heating to 520-580 ℃ at a heating rate of 5 ℃·min -1 and holding for 160-200 min (i.e. second stage), more preferably: heating to 400 ℃ at a heating rate of 4 ℃·min -1 and holding for 60 min (i.e. first stage), and then heating to 550 ℃ at a heating rate of 5 ℃·min -1 and holding for 180 min (i.e. second stage). The present application controls the phase heating rate, holding temperature and holding time of heat treatment in the above range to promote complete pyrolysis of urea in the first stage, release NH3, CO2 and other gases, form the basic framework of g-C3N4, at this time, C3N4 is a porous structure containing a large number of nitrogen vacancies and defects, iron ions coordinate with nitrogen atoms in C3N4 to form Fe-N bonds, and part of the iron may be reduced to low valence state (such as Fe 2+ ), oxygen-containing functional groups (from oxygenated conditions) begin to decompose, part of the oxygen atoms escape in the form of CO or CO2, and preliminary oxygen vacancies (Ov) are formed, but these vacancies are not stable; in the second stage, the C3N4 structure is further condensed and graphitized, the crystallinity is improved, and the nitrogen vacancies are reduced, but the oxygen vacancies are stabilized. High temperature causes more oxygen-containing species to desorb, resulting in an increase in oxygen vacancy concentration; iron atom migration: at high temperature, iron atoms gain enough kinetic energy and migrate on the surface of C3N4; oxygen vacancies, as high-energy sites, capture iron atoms and make them nucleate and grow, forming iron clusters (Fe-ACs); the size of the clusters is controlled by iron loading and heat treatment conditions; anchoring mechanism: oxygen vacancies form local electronic defects in the C3N4 skeleton, which have strong electronic interactions (such as charge transfer) with iron clusters, making the clusters stable and anchored. This anchoring prevents iron clusters from sintering or aggregating at high temperatures, maintaining high dispersity.

[0033] After the heat treatment is completed, the present application preferably grinds the heat-treated product to obtain an oxygen vacancy-deficient carbon nitride-anchored iron atom cluster catalyst.

[0034] The method for grinding is not particularly limited in the present application, and a technical solution known in the art can be used.

[0035] The present application also provides a catalyst for anchoring an iron atom cluster of carbon nitride with oxygen vacancy defects prepared by the preparation method.

[0036] In the present application, the loading of iron in the carbon nitride with oxygen vacancy defects in the catalyst for anchoring an iron atom cluster of carbon nitride with oxygen vacancy defects is 0.5-15 wt%, more preferably 0.8-12 wt%. In a specific embodiment, it can be 1 wt%, 2 wt%, 3 wt%, 5 wt% or 10 wt%. The present application controls the loading of iron in the carbon nitride with oxygen vacancy defects in the catalyst for anchoring an iron atom cluster of carbon nitride with oxygen vacancy defects in the above range to construct efficient and highly dispersed active sites. Within the above range, the iron content is low, the oxygen vacancies (Ov) on the carrier C3N4 are relatively sufficient, the iron precursor can be fully dispersed, and each iron atom or several iron atoms are captured by an oxygen vacancy to form an atomic level dispersed or ultra-small iron atom cluster. This structure can maximize the utilization efficiency of the metal and achieve high activity similar to a single atom.

[0037] The present application also provides an application of a catalyst for anchoring an iron atom cluster of carbon nitride with oxygen vacancy defects in degrading organic matter in water. The catalyst for anchoring an iron atom cluster of carbon nitride with oxygen vacancy defects is a catalyst for anchoring an iron atom cluster of carbon nitride with oxygen vacancy defects prepared by the preparation method or the catalyst for anchoring an iron atom cluster of carbon nitride with oxygen vacancy defects.

[0038] In the present application, the organic matter in water is preferably one of an antibiotic, a pesticide and an endocrine disruptor. In the present application, the antibiotic is preferably at least one of a tetracycline, a sulfonamide and a quinolone.

[0039] The method provided by the present application anchors iron atoms in the form of clusters in the structure of carbon nitride (Ov-C3N4) containing oxygen vacancy defects, stabilizes the iron atom clusters by forming Fe-Ov-C defect bonds between the oxygen vacancy defects in C3N4 and the iron atom clusters, solves the problem of thermodynamic instability of the catalyst while obtaining higher atomic utilization efficiency, reasonably regulates the electronic structure of the d-band center of the iron cluster through the Fe-Ov-C defect bonds, and greatly enhances the catalytic activity and cycle stability. In addition, the reaction of the iron atom clusters with persulfate leads to the breaking of O-O bonds and the formation of non-radical singlet oxygen, which can effectively solve the problem of sharp decline in catalytic efficiency caused by annihilation of free radicals in a complex water environment.

[0040] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0042] Example 1

[0043] A method for preparing a catalyst with oxygen vacancy-defective carbon nitride anchored iron atom clusters includes the following steps:

[0044] Weigh out urea to prepare a solution with a concentration of 1000 g·L. -1 The urea solution was then placed in a constant temperature water bath and heated to 60 °C with continuous stirring. Glucosamine was then added, and the mixture was placed in a 60 °C constant temperature water bath. The mixture was stirred every 5 min to ensure sufficient dispersion of iron atoms. Under oxygen-filled conditions (oxygen flow rate controlled at 40 mL / min), the mixture was continuously stirred for 120 min. The resulting transparent mixture was placed in a vacuum drying oven and dried at 60 °C until all moisture was evaporated, yielding an orange solid.

[0045] The obtained orange solid was transferred to a muffle furnace for heat treatment at 4 °C·min. -1 The temperature was increased to 400 °C and held for 60 min at a heating rate of 5 °C·min. -1 The temperature was increased to 550 °C and held for 180 min. Finally, after the furnace temperature dropped to room temperature, the crucible was removed, and the material was collected and ground to obtain a light orange powder, which is the catalyst for oxygen vacancy defect carbon nitride anchoring iron atom clusters, labeled as Fe-ACs / Ov-C3N4-1.

[0046] The loading of iron in the oxygen vacancy-defective carbon nitride anchored iron atom cluster catalyst is 1 wt%.

[0047] Examples 3-5

[0048] The catalyst of carbon nitride with oxygen vacancy anchoring iron atom cluster was prepared according to the method of Example 1, and the difference from Example 1 was that the amount of glucose iron was adjusted to obtain the catalyst of carbon nitride with oxygen vacancy anchoring iron atom cluster with the loading of iron in the carbon nitride with oxygen vacancy being 2 wt%, 3 wt%, 5 wt% and 10 wt% respectively, and the catalysts were labeled as Fe-ACs / Ov-C3N4-2, Fe-ACs / Ov-C3N4-3, Fe-ACs / Ov-C3N4-5 and Fe-ACs / Ov-C3N4-10 respectively.

[0049] Figure 1 The XRD patterns of the catalyst of carbon nitride with oxygen vacancy anchoring iron atom cluster Fe-ACs / Ov-C3N4-10 prepared in Example 5 and Ov-C3N4 were shown in FIG. 6. Figure 1 It can be seen that the catalyst of carbon nitride with oxygen vacancy anchoring iron atom cluster Fe-ACs / Ov-C3N4-10 was successfully synthesized in Example 5.

[0050] Figure 2 The FT-IR patterns of the catalyst of carbon nitride with oxygen vacancy anchoring iron atom cluster Fe-ACs / Ov-C3N4-10 prepared in Example 5 and Ov-C3N4 were shown in FIG. 7. Figure 2 It can be seen that the catalyst of carbon nitride with oxygen vacancy anchoring iron atom cluster Fe-ACs / Ov-C3N4-10 was successfully synthesized in Example 5.

[0051] Figure 3 The SEM, TEM, HTEM and Fe atomic energy spectrum of the catalyst of carbon nitride with oxygen vacancy anchoring iron atom cluster Fe-ACs / Ov-C3N4-10 prepared in Example 5 were shown in FIG. 8. Figure 3 In FIG. 8 (a), the SEM image was shown, Figure 3 In FIG. 8 (b), the TEM image was shown, Figure 3 In FIG. 8 (c), the HTEM image was shown, Figure 3 In FIG. 8 (d), the Fe atomic energy spectrum was shown.

[0052] Application Example 1

[0053] 20 mg of the catalyst Fe-ACs / Ov-C3N4-1 prepared in Example 1 was dispersed in 50 mL of norfloxacin NOR solution with a concentration of 6 mg / L, and then PDS was added. After that, the reaction beaker was quickly transferred to a stable light source, and the rotation speed of the turntable was set to 500 rpm. Then, 1 mL of reaction solution was taken every 5 minutes, filtered through a 0.22 μm filter membrane, and immediately 0.5 mL of anhydrous methanol was added to terminate the reaction. Then, the concentration of norfloxacin in the sample was detected, and the degradation efficiency of norfloxacin was calculated, which was used as Fe-ACs / PDS / Vis group.

[0054] The degradation efficiency of norfloxacin in PDS group, Vis group, FeCl3 group, PDS / Vis group, Fe-ACs / PDS group and Fe-ACs / PDS / Vis group was detected respectively according to the same method as in Application Example 1, and the difference from Application Example 1 is that the setting steps of each group are as follows:

[0055] PDS group: the difference from Application Example 1 is that Fe-ACs / Ov-C3N4-1 is omitted, and the light source is omitted;

[0056] Vis group: the difference from Application Example 1 is that Fe-ACs / Ov-C3N4-1 is omitted, and PDS is omitted;

[0057] FeCl3 group: the difference from Application Example 1 is that Fe-ACs / Ov-C3N4-1 is omitted, PDS is omitted, and only FeCl3 is added;

[0058] PDS / Vis group: the difference from Application Example 1 is that Fe-ACs / Ov-C3N4-1 is omitted;

[0059] Fe-ACs / PDS group: the difference from Application Example 1 is that the light source is omitted.

[0060] The degradation efficiency of norfloxacin in the different systems of each group was detected to obtain a degradation efficiency line graph as shown in Figure 4 .

[0061] According to the same method as in Application Example 1, the degradation efficiency of norfloxacin under different environmental media was detected respectively by using the catalyst Fe-ACs / Ov-C3N4-1 of Example 1, and the difference from Application Example 1 is that the setting steps of different environmental media are as follows:

[0062] In the PH influence experiment, 20 mg / L catalyst was dispersed in 50 ml NOR solution, then the solution PH was adjusted to 3, 5, 7, 9 respectively, and a blank control was set, 30 mg of sodium persulfate was added to each, then the beaker was quickly moved to the simulated visible light source, and the sample was taken at fixed time intervals for testing, and the obtained experimental results are shown in Figure 5 (a);

[0063] In the temperature influence experiment, 20 mg / L catalyst was dispersed in 50 ml NOR solution, then the solution temperature was controlled at 15℃, 30℃, 45℃, 60℃ respectively, 30 mg of sodium persulfate was added to each, then the beaker was quickly moved to the simulated visible light source, and the sample was taken at fixed time intervals for testing, and the obtained experimental results are shown in Figure 5 (b);

[0064] In the Cl -In the concentration effect experiment, 20 mg of catalyst was dispersed in 50 ml of NOR solution, and then NaCl was added to the beakers to make the Cl concentration in the beakers equal to the concentration of NOR. - Ion concentrations were set at 10 mmol, 20 mmol, and 30 mmol, respectively, with a blank control group included. The beakers were then quickly moved to a simulated visible light source, and samples were taken at fixed time intervals. The experimental results are shown below. Figure 5 As shown in (c);

[0065] In SO4 2- In the concentration effect experiment, 20 mg of catalyst was dispersed in 50 ml of NOR solution, and then Na2SO4 was added to the beakers to make the solution contain SO4. 2- Ion concentrations were set at 10 mmol, 20 mmol, and 30 mmol, respectively, with a blank control group included. The beakers were then quickly moved to a simulated visible light source, and samples were taken at fixed time intervals. The experimental results are shown below. Figure 5 As shown in (d);

[0066] In NO3 - In the concentration effect experiment, 20 mg of catalyst was dispersed in 50 ml of NOR solution, and then NaNO3 was added to the beakers to make the solution contain NO3. - Ion concentrations were set at 10 mmol, 20 mmol, and 30 mmol, respectively, with a blank control group included. The beakers were then quickly moved to a simulated visible light source, and samples were taken at fixed time intervals. The experimental results are shown below. Figure 5 As shown in (e);

[0067] In the experiment on the effect of HA concentration, 20 mg of catalyst was dispersed in 50 ml of NOR solution. Then, 0.5 mg, 1 mg, and 1.5 mg of HA were added to beakers, respectively, and a blank control group was set up with 30 mg of sodium persulfate added to each. The beakers were then quickly moved to simulated visible light, and samples were taken at fixed time intervals for testing. The experimental results are as follows. Figure 5 As shown in (f).

[0068] Figure 5 The line graphs showing the degradation efficiency of norfloxacin of the catalyst Fe-ACs / Ov-C3N4-1 in different environmental media in Example 1 of this invention are shown below. Figure 5 As shown.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst with oxygen vacancy-defective carbon nitride anchored to iron atom clusters, characterized in that, Includes the following steps: After preheating the urea solution, glucose iron was added, and the mixture was stirred under heating and oxygenation conditions. After drying, a solid was obtained. The solid was heat-treated to obtain a catalyst for oxygen-vacancy-defective carbon nitride anchored iron atom clusters.

2. The preparation method according to claim 1, characterized in that, The concentration of urea in the urea solution is 800~1200 g·L. -1 .

3. The preparation method according to claim 1, characterized in that, The heating temperature is 55~65 ℃, and the oxygen flow rate under the oxygenation conditions is 36~45 mL / min.

4. The preparation method according to claim 1, characterized in that, The stirring time is 100-150 min; the stirring frequency is once every 4-6 min.

5. The preparation method according to claim 1, characterized in that, The drying method involves drying at 55-65°C until all moisture is evaporated.

6. The preparation method according to claim 1, characterized in that, The heat treatment method is as follows: at 4 °C·min -1 Heat to 380~430℃ at a heating rate and hold for 50~80 min, then heat at a rate of 5℃·min. -1 Heat to 520~580 ℃ at a heating rate and hold for 160~200 min.

7. The preparation method according to claim 1, characterized in that, The heat treatment method is as follows: at 4 °C·min -1 The temperature was increased to 400℃ at a heating rate and held for 60 min, then increased at a rate of 5℃·min. -1 Heat to 550 °C at a heating rate and hold for 180 min.

8. The preparation method according to claim 1, characterized in that, The heat treatment process further includes grinding the heat-treated product to obtain a catalyst with oxygen vacancy defect carbon nitride anchored iron atom clusters.

9. A catalyst for anchoring iron atom clusters with oxygen vacancy-defective carbon nitride, prepared by the method according to any one of claims 1 to 8, characterized in that, The loading of iron in the oxygen vacancy defect carbon nitride anchored iron atom cluster catalyst is 0.5~15 wt%.

10. The application of a catalyst with oxygen vacancy-defective carbon nitride anchored to iron atom clusters in the degradation of organic matter in water, characterized in that, The catalyst for oxygen vacancy-defective carbon nitride anchoring iron atom clusters is the catalyst for oxygen vacancy-defective carbon nitride anchoring iron atom clusters prepared by the preparation method according to any one of claims 1 to 8, or the catalyst for oxygen vacancy-defective carbon nitride anchoring iron atom clusters according to claim 9.

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