FeNi2p / pcn-na ca photocatalyst, and preparation method and application thereof

Abstract

The application discloses a FeNi2P / PCN-NaCA photocatalyst and a preparation method and application thereof, belongs to the field of photocatalysts, and solves the problem of the restriction of existing carbon nitride materials on the hydrogen peroxide production efficiency of photocatalysis. The preparation method comprises the following steps: dissolving iron chloride, nickel nitrate and terephthalic acid in N,N-dimethylacetamide, and performing a hydrothermal reaction to obtain a FeNi2P precursor; heating the FeNi2P precursor and anhydrous sodium phosphate in a nitrogen atmosphere to obtain FeNi2P; calcining melamine to obtain PCN; and mixing the PCN, sodium thiocyanate solid and FeNi2P, and calcining in a nitrogen atmosphere to obtain the FeNi2P / PCN-NaCA photocatalyst. The FeNi2P / PCN-NaCA photocatalyst can efficiently utilize light to produce hydrogen peroxide, and has the characteristics of good stability and reusability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of photocatalysts, and particularly relates to a FeNi2P / PCN-NaCA photocatalyst, a preparation method and application thereof. BACKGROUND

[0002] H2O2 is one of the commonly used chemicals in the fields of chemical synthesis, pulp bleaching, disinfection and environmental remediation. At present, more than 95% of H2O2 is produced by the anthraquinone method. The traditional anthraquinone method for producing hydrogen peroxide has problems of high energy consumption, environmental pollution, safety risk, low efficiency, high transportation cost and the like.

[0003] Photocatalytic technology is a very promising renewable energy conversion technology, which can convert the abundant solar energy (1.3×105 TW) reaching the earth's surface into chemical energy that can be stored. This technology has been used for water splitting to produce hydrogen, CO2 reduction to produce carbon-based fuels or chemicals, and pollutant degradation.

[0004] Among the many semiconductor catalysts, it is found that unlike traditional semiconductor materials such as titanium dioxide and zinc oxide that can only absorb ultraviolet light, the band gap of graphite phase carbon nitride is 2.7 eV, which makes it also have photocatalytic effect in the visible light range. The conduction band potential of carbon nitride is -1.18 V, which is more negative than the potential of O2 reduction to H2O2 (0.695 V), so the photo-generated electrons on the conduction band of carbon nitride can reduce oxygen to hydrogen peroxide. Graphite phase carbon nitride has a layered structure similar to graphite, with strong van der Waals forces between the layers, which makes carbon nitride have stable chemical properties. In addition, carbon nitride can be prepared by thermal reaction of low-cost nitrogen-rich substances such as dicyandiamide, melamine and urea, etc., with low preparation cost. However, carbon nitride still has the defects of high recombination rate of photo-generated electron-hole pairs and low quantum efficiency, so its hydrogen peroxide production efficiency is not high.

[0005] FeNi2P is a phosphide with important transition metals, which has attracted extensive attention due to its excellent physical and chemical properties. This material shows good application prospects in the fields of catalysis, energy storage and conversion, especially in photocatalytic and electrocatalytic reactions. It is a compound with a dual-metal active site, with good electronic structure and electrochemical properties, and is widely used in water splitting and hydrogen generation reactions. Its excellent photoelectric performance enables it to effectively absorb light energy and promote the separation of photo-generated charges, thereby improving the photocatalytic efficiency. Studies have shown that FeNi2P combined with other photocatalytic materials (such as SnIn4S8) forms a Z-type heterojunction, which has a suitable band gap (-0.95 ~2.39 eV) that can significantly improve the migration and separation efficiency of photo-generated carriers. However, in some cases, FeNi2P may face problems such as photocorrosion, insufficient regenerability and potential impact on the environment.

[0006] Therefore, developing a visible light photocatalytic material that is simple to prepare, has higher visible light utilization, higher hydrogen peroxide production, better stability, and is reusable will be a key research goal in this field. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing FeNi2P / PCN-NaCA photocatalyst to solve the problem that existing carbon nitride materials limit the efficiency of photocatalytic hydrogen peroxide production.

[0008] Another objective of this invention is to provide a FeNi2P / PCN-NaCA photocatalyst, which is a heterojunction material with visible light response and efficient hydrogen peroxide production capability, thereby constructing an energy-saving photocatalytic system.

[0009] A third objective of this invention is to provide an application of the FeNi2P / PCN-NaCA photocatalyst.

[0010] The technical solution of this invention is:

[0011] (I) A method for preparing a FeNi2P / PCN-NaCA photocatalyst, comprising the following steps:

[0012] A. Preparation of FeNi2P precursor: A certain amount of ferric chloride, nickel nitrate, and terephthalic acid were dissolved in N,N-dimethylacetamide and stirred for 30-60 min to form a deep yellow solution. The solution was then placed in a 50 ml high-temperature reactor for hydrothermal reaction. The heating temperature of the hydrothermal reaction was 100-200 degrees Celsius, and the holding time was 2-4 hours. After the reaction was completed, the product was naturally cooled and ultrasonically cleaned with deionized water for 30-60 min. Then, the product was washed with anhydrous ethanol and dried to obtain the FeNi2P precursor.

[0013] B. Preparation of FeNi2P: FeNi2P precursor and a certain amount of anhydrous sodium phosphate were placed in two ceramic boats respectively and placed in a tube furnace. The anhydrous sodium phosphate was located upstream of the tube furnace, and the FeNi2P precursor was located downstream of the tube furnace. The furnace was heated in a nitrogen atmosphere at a temperature of 300-500 degrees Celsius for 1-3 hours. After the reaction was completed, the materials were cleaned by ultrasonication with deionized water for 30-60 minutes, and then the product was washed with anhydrous ethanol and dried to obtain FeNi2P.

[0014] C. Preparation of PCN: A certain mass of melamine is placed in a covered crucible and then placed in the center of a muffle furnace. Calcination is carried out in air atmosphere at a temperature of 400-600 degrees Celsius for 2-6 hours. After the reaction is complete, the material is cleaned by ultrasonication with deionized water for 30-60 minutes, and then the product is washed with anhydrous ethanol and dried to obtain PCN.

[0015] D. Preparation of FeNi2P / PCN-NaCA: A certain mass of PCN was placed in a ceramic boat, and then sodium thiocyanate solid and FeNi2P were mixed with it. A small amount of water was added to ensure uniform contact of the three components. The mixture was then placed in an oven at 50-70 degrees Celsius for drying. The dried sample was then placed in a tube furnace and calcined in a nitrogen atmosphere at a temperature of 400-800 degrees Celsius for 2-4 hours. The sample was then washed with deionized water and anhydrous ethanol and dried to obtain the FeNi2P / PCN-NaCA photocatalyst.

[0016] As a further improvement of the present invention, in step A, the mass ratio of ferric chloride, nickel nitrate and terephthalic acid is 1:3-8:1.

[0017] As a further improvement of the present invention, in step B, the mass ratio of FeNi2P precursor to anhydrous sodium phosphate is 1:1-4.

[0018] As a further improvement of the present invention, in step B, the heating rate of the tube furnace is 1-5 degrees Celsius per minute.

[0019] As a further improvement of the present invention, in step C, the heating rate of the muffle furnace is 5-10 °C / min.

[0020] As a further improvement of the present invention, in step D, the mass ratio of PCN, sodium thiocyanate and FeNi2P is 1:1:0.8-1.2.

[0021] As a further improvement of the present invention, in step D, the heating rate of the tubular furnace is 4-6 degrees Celsius per minute.

[0022] (ii) A FeNi2P / PCN-NaCA photocatalyst, prepared by the above-mentioned method for preparing FeNi2P / PCN-NaCA photocatalyst.

[0023] (III) Application of a FeNi2P / PCN-NaCA photocatalyst in the production of hydrogen peroxide.

[0024] Introducing metal ions into photocatalytic materials can not only modulate their photoelectric properties but also increase the number of active sites and photocatalytic stability during reactions, thereby affecting their light absorption and photogenerated charge behavior. First, introducing metal ions to modulate band structures and Fermi levels can optimize the reactivity of photocatalytic materials, making them more suitable for specific photocatalytic reactions. Second, the introduction of metal ions can form new active sites on the photocatalytic surface. These sites can adsorb reactants and promote the reaction. For example, the presence of sodium ions in PCN-NaCA enhances its oxygen adsorption capacity because the coordination between the metal and the triazine ring alters the electronic structure and electron cloud density of the framework. For bimetallic phosphides like FeNi2P, the introduction of iron atoms can lower the adsorption energy for hydrogen and oxygen, promoting their adsorption and desorption on the material surface. Finally, the introduction of metal ions also helps improve the stability of the photocatalyst because the interaction between metal ions and the copolymerized organic carbon framework enhances structural stability, thus maintaining the catalyst's activity during photocatalysis. FeNi2P itself possesses high electrocatalytic activity. Although it lacks photocatalytic hydrogen peroxide production capability, the construction of a heterojunction can promote the production of 2e- ... - The ORR reaction proceeds.

[0025] The beneficial effects of this invention are as follows: FeNi2P possesses a wide bandgap and strong redox ability, but requires a short photoexcitation wavelength. Modified copolynitride can complete photogenerated electron transitions under visible light irradiation, but hole-electron recombination is prone to occur. The Z-shaped heterojunction constructed by contacting FeNi2P and PCN-NaCA not only maintains strong redox ability but also suppresses the recombination of photogenerated carriers. By compositing FeNi2P and PCN-NaCA, the photogenerated electron-hole pairs in the FeNi2P / PCN-NaCA composite photocatalytic nanomaterial are successfully separated at the heterojunction, avoiding the electron-hole recombination problem in the bandgap of single PCN-NaCA catalytic nanomaterials. FeNi2P and PCN-NaCA form a complementary light absorption region in the visible light region. Furthermore, FeNi2P provides a large number of active sites for catalyzing the oxygen reduction reaction (ORR), while the functionalization modification of PCN-NaCA improves the conductivity and reaction stability of the material. By introducing metal ions and constructing heterojunctions, the composite material not only exhibits high antioxidant properties and stability under photocatalytic and electrocatalytic conditions, but also effectively enhances interfacial charge separation and electron transfer, thereby improving 2e oxidation. - The selectivity of the ORR reaction provides more reaction sites, ensuring the efficiency of H2O2 generation in the long-term reaction. The FeNi2P / PCN-NaCA photocatalyst of this invention can efficiently generate hydrogen peroxide using light irradiation, and has the characteristics of good stability and reusability. Attached Figure Description

[0026] Figure 1 SEM image of FeNi2P / PCN-NaCA prepared in Example 1 of this invention;

[0027] Figure 2 The following are the FT-IR spectra of FeNi2P / PCN-NaCA, FeNi2P, and PCN-NaCA prepared in Example 1 and Comparative Examples 1 and 2 of this invention.

[0028] Figure 3 The ultraviolet diffuse reflectance spectra of FeNi2P / PCN-NaCA, FeNi2P, and PCN-NaCA prepared in Example 1 and Comparative Examples 1 and 2 of this invention are shown.

[0029] Figure 4 This is a comparison chart of the visible light catalytic hydrogen peroxide production performance of FeNi2P / PCN-NaCA, FeNi2P, and PCN-NaCA prepared in Example 1 and Comparative Examples 1 and 2 of this invention;

[0030] Figure 5 This is a cyclic experiment diagram of hydrogen peroxide production from FeNi2P / PCN-NaCA prepared in Example 1 of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] The terephthalic acid (C8H6O4), ferric chloride (FeCl3), nickel nitrate (Ni(NO3)2), and anhydrous sodium phosphate (Na3PO4) used in the following examples and comparative examples were all purchased from Aladdin (Shanghai, China); all reagents were ready to use without further purification; and all experiments used deionized water.

[0033] Example 1

[0034] A method for preparing a FeNi2P / PCN-NaCA photocatalyst includes the following steps:

[0035] A. Preparation of FeNi2P precursor: 162 mg ferric chloride, 851 mg nickel nitrate, and 166 mg terephthalic acid were dissolved in 30 mL of N,N-dimethylacetamide and stirred for 30 min to form a deep yellow solution. The solution was then placed in a 50 mL high-temperature reactor for hydrothermal reaction and heated at 150 °C for 3 hours. After the reaction was completed, the solution was allowed to cool naturally. The product was then washed with deionized water by sonication for 60 min, followed by washing with anhydrous ethanol. After drying at 60 °C, the FeNi2P precursor was obtained.

[0036] B. Preparation of FeNi2P: 100 mg each of FeNi2P precursor and anhydrous sodium phosphate were placed in two ceramic boats and placed in a tube furnace, with the anhydrous sodium phosphate located upstream and the FeNi2P precursor located downstream. Under a nitrogen atmosphere, the temperature was increased to 350°C at a rate of 3°C / min and maintained for 2 hours. After the reaction was completed, the mixture was cooled, and the material was cleaned by sonication with deionized water for 60 min. Then, the product was washed with anhydrous ethanol and dried to obtain FeNi2P material.

[0037] C. Preparation of PCN: 10g of melamine was ground and placed in a covered crucible, then placed in the center of a muffle furnace and calcined at 600℃ in air for 2 hours at a heating rate of 5℃ / min. After the reaction was completed, the mixture was cooled, and the material was cleaned by ultrasonication with deionized water for 60 min. Then the product was washed with anhydrous ethanol and dried at 60℃ to obtain PCN material.

[0038] D. Preparation of FeNi2P / PCN-NaCA: 1g of PCN was ground and placed in a porcelain boat, mixed with 1g of sodium thiocyanate and 1g of FeNi2P in the presence of a small amount of water, and the mixture was dried in an oven at 60°C. Then, it was pyrolyzed in a tube furnace at 400°C for 4 hours in a nitrogen atmosphere at a heating rate of 5°C / min. After cooling, the material was washed three times with anhydrous ethanol and deionized water, and dried at 60°C to obtain the FeNi2P / PCN-NaCA photocatalyst.

[0039] Figure 1 This is a SEM image of the FeNi2P / PCN-NaCA photocatalyst prepared in this embodiment. Figure 1 The shape and size of the material are shown; the FeNi2P / PCN-NaCA composite photocatalytic nanomaterial has a non-uniform stacked nanosheet structure.

[0040] Comparative Example 1

[0041] The preparation of FeNi2P materials includes the following steps:

[0042] Step 1: Preparation of FeNi2P precursor: 162 mg ferric chloride, 851 mg nickel nitrate, and 166 mg terephthalic acid were dissolved in 30 mL of N,N-dimethylacetamide and stirred for 30 min to form a deep yellow solution. The solution was then placed in a 50 mL high-temperature reactor for hydrothermal reaction and heated at 150 °C for 3 hours. After the reaction was completed, the solution was allowed to cool naturally. The product was then ultrasonically washed with deionized water for 60 min, followed by washing with anhydrous ethanol. After drying at 60 °C, the FeNi2P precursor was obtained.

[0043] Step 2, Preparation of FeNi2P: 100 mg each of FeNi2P precursor and anhydrous sodium phosphate were placed in two ceramic boats and placed in a tube furnace, with the anhydrous sodium phosphate located upstream and the FeNi2P precursor located downstream. Under a nitrogen atmosphere, the temperature was increased to 350°C at a rate of 3°C / min and maintained for 2 hours. After the reaction was completed, the mixture was cooled, and the materials were cleaned by sonication with deionized water for 60 min. The product was then washed with anhydrous ethanol and dried to obtain FeNi2P material.

[0044] Comparative Example 2

[0045] The preparation of PCN-NaCA material includes the following steps:

[0046] Step 1: Preparation of PCN: 10g of melamine was ground and placed in a covered crucible, then placed in the center of a muffle furnace and calcined at 550℃ in air for 4 hours at a heating rate of 5℃ / min. After the reaction was completed, the mixture was cooled, and the material was cleaned by ultrasonication with deionized water for 60 min. Then the product was washed with anhydrous ethanol and dried at 60℃ to obtain the PCN precursor.

[0047] Step 2: Preparation of FeNi2P / PCN-NaCA: Take 1g of PCN precursor, grind it and place it in a porcelain boat. Mix it with 1g of sodium thiocyanate in the presence of a small amount of water and stir. Place the mixture in an oven at 60 degrees Celsius to dry it. Then, in a tube furnace, heat it at 400 degrees Celsius at a heating rate of 5 degrees Celsius / min for 6 hours in a nitrogen atmosphere. After cooling, wash the material three times with anhydrous ethanol and deionized water respectively, and dry it at 60 degrees Celsius to obtain PCN-NaCA material.

[0048] Figure 2 The FT-IR spectra of FeNi2P / PCN-NaCA, FeNi2P, and PCN-NaCA prepared in Example 1 and Comparative Examples 1 and 2 are shown. Two types of characteristic peaks were observed in FeNi2P, located at 1040 cm⁻¹. -1 and 1000cm -1 The following wavenumbers are used. The former corresponds to the stretching vibration of PO in FeNi₂P, while the latter can be attributed to the stretching vibration mode of the MO metal-oxygen bond. Comparison of peak intensities and characteristic peaks confirms the successful synthesis of FeNi₂P. In PCN-NaCA, the wavenumbers are in the range of 3000-3500 cm⁻¹. -1 A strong and broad absorption peak exists between the two materials, corresponding to the stretching vibration of the amino group in the triazine ring. Furthermore, characteristic peaks of both FeNi2P and PCN-NaCA materials were observed in FeNi2P / PCN-NaCA, further demonstrating the successful composite composition.

[0049] Figure 3The UV diffuse reflectance spectra of FeNi2P / PCN-NaCA, FeNi2P, and PCN-NaCA prepared in Example 1 and Comparative Examples 1 and 2 are shown. It can be observed that although the light absorption of both FeNi2P and PCN-NaCA covers the entire visible absorption spectrum, the light absorption of PCN-NaCA material is significantly weakened above 450 nm, indicating that PCN-NaCA material alone cannot effectively absorb visible light. After combining the two, the light absorption of FeNi2P / PCN-NaCA material covers the entire visible spectrum, indicating an improvement in its light-collecting efficiency. Furthermore, compared to PCN-NaCA alone, the absorption peak of FeNi2P / PCN-NaCA remains almost unchanged, demonstrating the visible light activity of FeNi2P and indicating that the construction of the heterojunction does not significantly alter the light absorption.

[0050] Example 2

[0051] A method for preparing a FeNi2P / PCN-NaCA photocatalyst includes the following steps:

[0052] A. Preparation of FeNi2P precursor: 162 mg ferric chloride, 486 mg nickel nitrate, and 166 mg terephthalic acid were dissolved in 30 mL of N,N-dimethylacetamide and stirred for 30 min to form a deep yellow solution. The solution was then placed in a 50 mL high-temperature reactor for hydrothermal reaction and heated at 100 °C for 4 hours. After the reaction was completed, the solution was allowed to cool naturally. The product was then washed with deionized water by sonication for 30 min, followed by washing with anhydrous ethanol. After drying at 60 °C, the FeNi2P precursor was obtained.

[0053] B. Preparation of FeNi2P: 100 mg of FeNi2P precursor and 400 mg of anhydrous sodium phosphate were placed in two ceramic boats and placed in a tube furnace, with the anhydrous sodium phosphate located upstream and the FeNi2P precursor located downstream. Under a nitrogen atmosphere, the temperature was increased to 300°C at a rate of 3°C / min and maintained for 3 hours. After the reaction was completed, the mixture was cooled, and the material was cleaned by sonication with deionized water for 30 min. Then, the product was washed with anhydrous ethanol and dried to obtain FeNi2P material.

[0054] C. Preparation of PCN: 5g of melamine was ground and placed in a covered crucible, then placed in the center of a muffle furnace and calcined in air at 550℃ for 4 hours at a heating rate of 5℃ / min. After the reaction was completed, the mixture was cooled, and the material was cleaned by ultrasonication with deionized water for 30 minutes. Then the product was washed with anhydrous ethanol and dried at 60℃ to obtain PCN material.

[0055] D. Preparation of FeNi2P / PCN-NaCA: 1g of PCN was ground and placed in a porcelain boat, mixed with 1g of sodium thiocyanate and 1.2g of FeNi2P in the presence of a small amount of water, and the mixture was dried in an oven at 60°C. Then, it was pyrolyzed in a tube furnace at 800°C for 2 hours under a nitrogen atmosphere at a heating rate of 5°C / min. After cooling, the material was washed three times with anhydrous ethanol and deionized water, and dried at 60°C to obtain the FeNi2P / PCN-NaCA photocatalyst.

[0056] Example 3

[0057] A method for preparing a FeNi2P / PCN-NaCA photocatalyst includes the following steps:

[0058] A. Preparation of FeNi2P precursor: 162 mg ferric chloride, 1296 mg nickel nitrate, and 166 mg terephthalic acid were dissolved in 30 mL of N,N-dimethylacetamide and stirred for 30 min to form a deep yellow solution. The solution was then placed in a 50 mL high-temperature reactor for hydrothermal reaction and heated at 200 °C for 2 hours. After the reaction was completed, the solution was allowed to cool naturally. The product was then washed with deionized water by sonication for 45 min, followed by washing with anhydrous ethanol. After drying at 60 °C, the FeNi2P precursor was obtained.

[0059] B. Preparation of FeNi2P: 100 mg of FeNi2P precursor and 400 mg of anhydrous sodium phosphate were placed in two ceramic boats and placed in a tube furnace, with the anhydrous sodium phosphate located upstream and the FeNi2P precursor located downstream. Under a nitrogen atmosphere, the temperature was increased to 500°C at a rate of 3°C / min and maintained for 1 hour. After the reaction was completed, the mixture was cooled, and the material was cleaned by sonication with deionized water for 45 min. Then, the product was washed with anhydrous ethanol and dried to obtain FeNi2P material.

[0060] C. Preparation of PCN: 20g of melamine was ground and placed in a covered crucible, then placed in the center of a muffle furnace and calcined at 400℃ in air for 6 hours at a heating rate of 10℃ / min. After the reaction was completed, the mixture was cooled, and the material was cleaned by ultrasonication with deionized water for 45 minutes. Then the product was washed with anhydrous ethanol and dried at 60℃ to obtain PCN material.

[0061] D. Preparation of FeNi2P / PCN-NaCA: 1g of PCN was ground and placed in a porcelain boat, mixed with 1g of sodium thiocyanate and 0.8g of FeNi2P in the presence of a small amount of water, and the mixture was dried in an oven at 60°C. Then, it was pyrolyzed in a tube furnace at 800°C for 2 hours under a nitrogen atmosphere at a heating rate of 5°C / min. After cooling, the material was washed three times with anhydrous ethanol and deionized water, and dried at 60°C to obtain the FeNi2P / PCN-NaCA photocatalyst.

[0062] (I) Evaluation of photocatalytic activity:

[0063] The photocatalysts FeNi2P / PCN-NaCA, FeNi2P, and PCN-NaCA prepared in Example 1 and Comparative Examples 1 and 2 were used to conduct experiments on the photosynthesis of H2O2, as follows:

[0064] 10 mg of catalyst was added to 20 mL of 10 vol% ethanol solution and stirred at 350 rpm / min. Before illumination, the solution was aerated and stirred for 30 min in the dark to allow the solution to reach adsorption / desorption equilibrium. A xenon lamp was used as a simulated solar light source, filtered through a 420 nm filter, with a light intensity of 100 mW / cm². 2 After exposure to light, 1 mL of the suspension was taken with a disposable needle and filtered through a 0.22 μm microporous filter. The concentration of H2O2 in the resulting transparent filtrate was determined by the iodide ion standardization method.

[0065] The detection method for H2O2 is as follows: Add 1 mL of C8H5KO4 aqueous solution (0.1 M) and 1 mL of KI aqueous solution (0.4 M) to the above clear filtrate (1 mL), and then keep for 30 minutes. H2O2 reacts with I... − A reaction occurs between them to produce triiodide anion (I2). 3- The H2O2 concentration exhibits a characteristic absorption peak at approximately 350 nm. Therefore, a linear relationship between the concentration and the absorbance can be calculated by fitting the data, thereby determining the concentration of H2O2 in the catalytic system.

[0066] Figure 4 The image shows a comparison of the visible light photocatalytic hydrogen peroxide production performance of FeNi2P / PCN-NaCA, FeNi2P, and PCN-NaCA prepared in Example 1 and Comparative Examples 1 and 2. Figure 4As shown, the 1-hour hydrogen peroxide production of FeNi2P alone is 0.8215 mM, while that of PCN-NaCA alone is 2.847 mM. This indicates that FeNi2P alone does not possess significant photocatalytic hydrogen production activity, and even with appropriate energy level positions, PCN-NaCA alone does not exhibit outstanding photocatalytic hydrogen production activity due to rapid in-situ carrier recombination. Ultimately, the 1-hour hydrogen peroxide production of the FeNi2P / PCN-NaCA heterojunction composite material constructed in this invention is increased to 3.3545 mM.

[0067] (II) Cyclic Experiment:

[0068] After the first reaction of FeNi2P / PCN-NaCA prepared in Example 1 was completed, the solution containing the photocatalyst was centrifuged, and the lower layer material was dried at 60°C for 8 hours. Then it was put back into the reactor for the next photoreaction. Except for the material, the other reaction conditions were kept the same as the first time. After the second reaction was completed, the above steps were repeated, and a total of five hydrogen peroxide production experiments were carried out.

[0069] Figure 5 The diagram shows the cyclic experiment of hydrogen peroxide production from FeNi2P / PCN-NaCA prepared in Example 1. Figure 5 As shown, the hydrogen peroxide production was above 3 mM in three consecutive experiments, and the hydrogen production activity of the FeNi2P / PCN-NaCA photocatalytic nanomaterial remained good after five cycles, indicating that the material has good stability.

[0070] Experimental results show that under the above-mentioned experimental conditions for photosynthesis of H2O2, the FeNi2P / PCN-NaCA photocatalytic material produced a hydrogen peroxide concentration of 3.3545 mmol / L after 60 minutes, which is significantly higher than that of similar photocatalysts. Moreover, the material exhibits stable photocatalytic performance after several reactions, can be recycled, and can produce a large amount of hydrogen peroxide under prolonged light irradiation, thus possessing practical application value.

[0071] The FeNi2P / PCN-NaCA catalyst of this invention is not limited to hydrogen peroxide production; its application in the Fenton reaction in the environmental field is imminent. This system exhibits high hydrogen peroxide concentration, high visible light utilization, and low electron-hole recombination rate. Under visible light irradiation, both the FeNi2P / PCN-NaCA photocatalysts are photoexcited to generate photogenerated electrons and holes. The matched energy level positions allow photogenerated electrons from the FeNi2P conduction band to transfer across the heterojunction interface to the PCN-NaCA valence band. This Z-type charge transport mechanism not only promotes carrier separation and effectively suppresses electron-hole recombination but also retains strong redox capabilities. The photogenerated electrons can effectively combine with adsorbed oxygen on the material surface to generate highly oxidizing reactive oxygen species such as superoxide radicals or singlet oxygen, thereby efficiently removing organic pollutants.

Claims

1. A method for preparing a FeNi2P / PCN-NaCA photocatalyst, characterized in that... Includes the following steps: A. Preparation of FeNi2P precursor: Iron chloride, nickel nitrate, and terephthalic acid were dissolved in N,N-dimethylacetamide, stirred, and placed in a reaction vessel for hydrothermal reaction. The heating temperature of the hydrothermal reaction was 100-200 degrees Celsius, and the holding time was 2-4 hours. After the reaction was completed, the product was naturally cooled, washed, and dried to obtain the FeNi2P precursor. B. Preparation of FeNi2P: FeNi2P precursor and anhydrous sodium phosphate were placed in two ceramic boats respectively and placed in a tube furnace. The furnace was heated in a nitrogen atmosphere at a temperature of 300-500 degrees Celsius for 1-3 hours. After the reaction was completed, the product was washed and dried to obtain FeNi2P. C. Preparation of PCN: Melamine is placed in a muffle furnace and calcined in air at a temperature of 400-600 degrees Celsius for 2-6 hours. After the reaction is complete, the product is washed and dried to obtain PCN. D. Preparation of FeNi2P / PCN-NaCA: Take PCN, then take sodium thiocyanate solid and FeNi2P and mix them together. Add water to make the three substances come into uniform contact. Place the mixture in an oven to dry. Place the dried sample in a tube furnace and calcine it in a nitrogen atmosphere. The calcination temperature of the tube furnace is 400-800 degrees Celsius and the holding time is 2-4 hours. Then wash the sample and dry it to obtain the FeNi2P / PCN-NaCA photocatalyst.

2. The preparation method of the FeNi2P / PCN-NaCA photocatalyst according to claim 1, characterized in that: In step A, the mass ratio of ferric chloride, nickel nitrate, and terephthalic acid is 1:3-8:

1.

3. The method for preparing a FeNi2P / PCN-NaCA photocatalyst according to claim 1, characterized in that: In step B, the mass ratio of FeNi2P precursor to anhydrous sodium phosphate is 1:1-4.

4. The preparation method of the FeNi2P / PCN-NaCA photocatalyst according to claim 1, characterized in that: In step B, the heating rate of the tube furnace is 1-5 degrees Celsius per minute.

5. The method for preparing a FeNi2P / PCN-NaCA photocatalyst according to claim 1, characterized in that: In step C, the heating rate of the muffle furnace is 5-10 °C / min.

6. The method for preparing a FeNi2P / PCN-NaCA photocatalyst according to claim 1, characterized in that: In step D, the mass ratio of PCN, sodium thiocyanate, and FeNi2P is 1:1:0.8-1.

2.

7. The method for preparing a FeNi2P / PCN-NaCA photocatalyst according to claim 1, characterized in that: In step D, the heating rate of the tube furnace is 4-6 degrees Celsius per minute.

8. A FeNi2P / PCN-NaCA photocatalyst, characterized in that: The FeNi2P / PCN-NaCA photocatalyst is prepared by any one of claims 1-7.

9. The application of the FeNi2P / PCN-NaCA photocatalyst according to claim 8 in the production of hydrogen peroxide.

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