A graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance and a preparation method and application thereof
By using a composite catalyst of graphitic carbon nitride, vanadium pentoxide, and MXene, the problem of catalytic performance degradation of traditional photocatalysts in the dark was solved, and a light-dark continuous catalytic system was constructed, achieving efficient catalytic oxidation degradation under both light and dark conditions.
Patent Information
- Application Number
- CN202510958313.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2045-07-11
AI Technical Summary
Traditional photocatalysts exhibit excellent catalytic activity under light conditions, but their catalytic performance significantly decreases under light-free conditions. Furthermore, existing light-dark cycle catalysts have limited energy storage capacity, poor interfacial structural stability, and lack deep energy storage mechanisms, resulting in poor dark-state catalytic performance.
A composite catalyst using graphitic carbon nitride (g-C3N4), vanadium pentoxide (V2O5), and MXene was developed to achieve continuous light-dark catalytic performance through calcination at a specific temperature and gas atmosphere. V2O5 stores electrons and releases them in the dark state, while MXene promotes electron transfer and the construction of microscopic proton cells, thereby enhancing catalyst stability.
It achieves efficient oxidation and degradation of antibiotics in water under both light and dark conditions, exhibiting excellent light-dark continuous catalytic oxidation effect and improving the stability and efficiency of the catalyst.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of chemical catalysts, and particularly relates to a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance and a preparation method and application thereof. BACKGROUND
[0002] Traditional pollutant degradation technologies face challenges such as high energy consumption, secondary pollution and low efficiency, and developing efficient, green and economic pollutant treatment methods has become an important issue in the field of environmental governance. Because photocatalytic technology has the potential to convert solar energy into chemical energy, it has attracted much attention in the fields of environmental governance and energy conversion. However, the catalytic activity of traditional photocatalysts is highly dependent on light, and only performs well under light radiation conditions, while the catalytic performance is greatly reduced under dark conditions. Therefore, it is of great significance to study catalytic materials with light-dark continuous catalytic performance for the practical application of photocatalytic technology.
[0003] As a new photocatalytic material, g-C3N4 has attracted much attention due to its excellent thermal stability and chemical stability, but its limited light response range, high carrier recombination rate and low surface ratio seriously affect its photocatalytic performance (Zheng Z, Du T, Chen P, et al. Journal of Environmental Chemical Engineering, 2024, 12(3): 112971.). Most composite materials that can continuously exert photocatalytic activity in light-dark cycles are usually combined with traditional photocatalysts (such as TiO2, ZnO, g-C3N4, etc.) and energy storage materials (such as Ni(OH)2, MoO x , WO3, V2O5, etc.) to form a synergistic effect, thereby effectively improving their photocatalytic performance and energy storage performance (Zhang C, Li Y, Li M, et al. Journal of Hazardous Materials, 2021, 420: 126607.). However, traditional composite catalysts that can continuously exert photocatalytic activity in light-dark cycles have limited energy storage capacity, poor interface structure stability, lack of deep energy storage mechanism and reaction selectivity, and limited degradation depth, resulting in poor dark-state catalytic performance. Therefore, the present application proposes a novel graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance and a preparation method and application thereof. SUMMARY
[0004] To solve the above technical problems, the present application proposes a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance and a preparation method and application thereof.
[0005] To achieve the above purpose, the present application provides the following technical solutions:
[0006] One of the technical solutions of the present application is:
[0007] A graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance, the raw materials include graphite phase carbon nitride (g-C3N4), vanadium pentoxide (V2O5) and MXene material, the vanadium pentoxide accounts for 2-10% of the mass of the graphite phase carbon nitride, and the MXene material accounts for 3-7% of the mass of the graphite phase carbon nitride.
[0008] In the present application, g-C3N4 is the basic material for photocatalytic reaction. Its unique layered structure and suitable energy band structure enable it to absorb photon energy under visible light radiation, excite valence band electrons to jump to the conduction band, and generate electron-hole pairs. After these photo-generated carriers migrate to the surface of the material, the holes can oxidize the organic pollutants adsorbed on the surface of the catalyst, and at the same time, the conduction band electrons can react with dissolved oxygen to generate active species such as superoxide radicals, further promoting the oxidative degradation reaction of organic pollutants, and providing the initial reaction power for the whole catalytic system.
[0009] V2O5 absorbs photon energy under light, and the V 5+ ions inside can capture photo-generated electrons and be reduced to metastable V 4+ , realizing effective storage of electrons. When the system is in a dark environment, the stored electrons can be slowly released, maintaining the continuous oxidation-reduction reaction of the system, thereby ensuring the catalytic activity of the catalyst in the dark. This electron storage and release mechanism effectively compensates for the limitation that photocatalysis can only work under light, providing an electron source for light-dark continuous catalysis.
[0010] MXene material, with its excellent electrical conductivity and unique two-dimensional structure, is mainly responsible for promoting the rapid transfer and absorption of electrons in the system. Mxene has good metal conductivity, which can meet the rapid transfer of charge carriers. The surface is covered with a large number of hydrophilic functional groups (such as -OH, -O, etc.), which can interact strongly with g-C3N4. It can quickly capture the photo-generated electrons produced by g-C3N4, effectively inhibit the recombination of electron-hole pairs, and greatly improve the utilization efficiency of electrons. On the other hand, the rich functional groups (such as -OH, -F, etc.) on the surface of MXene enable it to interact with V2O5, forming a micro proton battery. In this micro proton battery structure, MXene acts as an electron transport channel, and V2O5 acts as an electrode material for electron storage and release. The two work together to enable electrons to transfer in an orderly manner within the system, maintain the balance of charges within the system, and enhance the stability of the entire composite catalyst system.
[0011] Based on the role of each raw material, g-C3N4 generates photo-generated carriers and provides a reaction site, V2O5 stores and adjusts electrons to achieve continuous reaction under light and dark conditions, and MXene promotes electron transfer and stabilizes the system. In the light phase, g-C3N4 generates electron-hole pairs, MXene quickly transfers electrons, reduces recombination, and V2O5 absorbs electrons and stores them; after entering the dark phase, V2O5 releases the stored electrons and maintains the redox reaction with MXene, while the remaining holes on the surface of g-C3N4 and the generated active species such as hydroxyl radicals continue to participate in the oxidative degradation of antibiotics. This synergistic mechanism enables the composite catalyst to continuously and efficiently oxidize and degrade antibiotics in water under light, dark, and light-dark alternating conditions, exhibiting excellent light-dark continuous catalytic oxidation effect.
[0012] The second technical solution of the present application is:
[0013] A preparation method of the above-mentioned graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance, comprising the following steps:
[0014] (1) Mix and grind graphite phase carbon nitride and vanadium pentoxide powder, perform first calcination to obtain g-C3N4 / V2O5 composite catalyst;
[0015] (2) Mix and grind the g-C3N4 / V2O5 composite catalyst with MXene material, perform second calcination to obtain the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance.
[0016] Further, in step (1), the temperature of the first calcination is 400-500 DEG C, and the calcination time is 2-3h.
[0017] Further, in step (1), the heating rate of the first calcination is 4-6 DEG C / min, and the gas atmosphere is air.
[0018] In step (1), the mixed grinding makes the V2O5 powder uniformly adhere to the surface of g-C3N4, and the interface contact is formed between the two through heat diffusion during the calcination process, thereby enhancing the structural stability of the composite catalyst; under the air atmosphere at 400-500 DEG C, the layered structure of g-C3N4 is moderately reconstructed, and V2O5 is transformed from a crystal state to an amorphous or nano-sized particle, which is uniformly dispersed in the interlayer or surface of g-C3N4, thereby increasing the number of active sites.
[0019] Further, in step (2), the temperature of the second calcination is 300-350 DEG C, and the calcination time is 1-3h.
[0020] Further, in step (2), the heating rate of the second calcination is 2-4 DEG C / min, and the gas atmosphere is inert gas.
[0021] In step (2), the inert gas (such as argon, nitrogen) atmosphere at 300-350 DEG C can avoid the oxidation of the MXene material, while promoting its interface with g-C3N4 / V2O5 by heat, forming a "g-C3N4 / V2O5 / MXene" heterojunction network, and through the two-dimensional conductive layer of MXene and the electron storage site of V2O5, a direct contact is formed by calcination, the electron transfer path is shortened, and the electron transport efficiency is improved. Calcination promotes the reaction of V2O5 and the surface functional groups of MXene, builds a micro proton transport channel (similar to the structure of a proton battery), combines the stored electrons of V2O5 with the protons (H + ) adsorbed by MXene, generates active oxygen species, and enhances the dark reaction catalytic capacity.
[0022] The third technical solution of the present application is:
[0023] The application of the above-mentioned graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance in degrading antibiotics in water.
[0024] Further, the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance can degrade antibiotics in water under light-dark alternating conditions.
[0025] Further, the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance is added to the water in an amount of 4 mg / 10 mL.
[0026] Further, the concentration of the antibiotic in the water is 20 mg / L.
[0027] Compared with the prior art, the present application has the following advantages and technical effects:
[0028] The present application prepares a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance by calcining graphite phase carbon nitride, vanadium pentoxide and MXene material at a specific temperature and under specific gas protection; among the raw materials used, graphite phase carbon nitride can promote the oxidative degradation reaction of organic pollutants in water or air under light radiation conditions; vanadium pentoxide absorbs electrons V ions from the stable 5 + to metastable 4 + , stores electrons; MXene can promote the transfer and absorption of electrons, and can build a micro proton battery with vanadium pentoxide, making the system more stable; the synergistic effect of the three raw materials, the composite catalyst constructed for the oxidative degradation of antibiotics (tetracycline hydrochloride) in water has high light-dark continuous catalytic oxidation effect. BRIEF DESCRIPTION OF DRAWINGS
[0029] The accompanying drawings, which constitute a part of this specification, are included to provide a further understanding of the application and of certain
[0030] Figure 1 Results of degradation rate of tetracycline hydrochloride by graphite phase carbon nitride composite catalyst prepared for Examples 1-8, composite catalyst in Comparative Example 1 under dark conditions;
[0031] Figure 2 Results of degradation rate of tetracycline hydrochloride by graphite phase carbon nitride composite catalyst prepared for Example 2, composite catalyst in Comparative Examples 1-6 under dark conditions;
[0032] Figure 3 Results of hydroxyl radical determination of graphite phase carbon nitride composite catalyst (VCT-5) prepared in Example 2;
[0033] Figure 4 Results of superoxide radical determination of graphite phase carbon nitride composite catalyst (VCT-5) prepared in Example 2;
[0034] Figure 5 Cyclic voltammogram of graphite phase carbon nitride composite catalyst (VCT-5) prepared in Example 2. DETAILED DESCRIPTION
[0035] Various illustrative embodiments of the present application are now described in detail below. The description given herein of the various illustrative embodiments is intended to be illustrative only and merely representative of the breadth of the present application as contemplates by the inventors. The description is not intended to be exhaustive or to be limited to the precise forms disclosed herein.
[0036] It should be understood that the terms used herein are merely descriptive, but that the application should not be construed as being limited thereto. In addition, with respect to numerical ranges in the present application, it is to be understood that every intervening value, to the upper and lower limits of the ranges stated herein, is also specifically disclosed. Each smaller range between any stated value or intervening value in the stated ranges and any other stated or intervening value in that stated range is encompassed. The upper and lower limits of these smaller ranges can independently be included or excluded in the range.
[0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In the event of conflict between the present specification and any document incorporated by reference, the present specification controls.
[0038] Many modifications and variations to the illustrative embodiments described herein will be apparent to those of ordinary skill in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the present application. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.
[0039] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean inclusion, but not limited to, the listed material or list of materials.
[0040] The embodiment of the present application provides a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance, raw materials include graphite phase carbon nitride (g-C3N4), vanadium pentoxide (V2O5) and MXene material, vanadium pentoxide accounts for 2-10% of the mass of graphite phase carbon nitride, and MXene material accounts for 3-7% of the mass of graphite phase carbon nitride.
[0041] When the amount of V2O5 is less than 2%, the V 5+ The active site is insufficient, the amount of stored electrons under light is limited, and the amount of electron release under dark condition is difficult to maintain continuous catalysis, resulting in a significant decrease in dark reaction efficiency. If the amount exceeds 10%, the excess V2O5 will form agglomerates on the surface of g-C3N4, shielding the photocatalytic active sites and reducing the light absorption efficiency of g-C3N4; at the same time, too much V 4+ / V 5+ The redox couple may destroy the charge balance of the system, resulting in an increase in the electron-hole recombination rate.
[0042] When the amount of MXene material is less than 1%, MXene cannot form a continuous conductive network on the surface of g-C3N4 / V2O5, the transfer efficiency of electrons from the conduction band of g-C3N4 to V2O5 is reduced, resulting in an increase in the recombination rate of photo-generated carriers. When it exceeds 7%, the MXene layers are stacked and agglomerated due to van der Waals force, the specific surface area is reduced, the exposed active sites are reduced, and at the same time, too much MXene may compete with g-C3N4 for adsorption of antibiotics, reducing the catalytic efficiency.
[0043] The g-C3N4 used in the embodiments of the application is prepared according to the literature [Qingbo Xu, Peng Wang, Zongqian Wang, Jiakun Shen, Xu Han. Kechen Song, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 648, 2022, 129392,]. The V2O5 used is purchased from Shanghai Aladdin Bio-Reagent Co., Ltd. The MXene material used is prepared according to the literature [X. Zheng, P. Wang, X. Zhang, Q. Hu, Z. Wang, W. Nie, L. Zou, C. Li, X. Han, Composites Part A: Applied Science and Manufacturing, 152 (2022)].
[0044] A preparation method of the above-mentioned graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance, comprising the following steps:
[0045] (1) mixing and grinding graphite phase carbon nitride and vanadium pentoxide powder, calcining to obtain a g-C3N4 / V2O5 composite catalyst (referred to as xVC, wherein x is the mass fraction of V2O5 relative to g-C3N4);
[0046] (2) uniformly mixing the g-C3N4 / V2O5 composite catalyst with MXene material, and calcining to obtain a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance (g-C3N4 / V2O5 / Mxene, referred to as VCT-x, wherein x is the mass fraction of MXene relative to g-C3N4).
[0047] In step (1) of the preferred embodiment of the application, the calcination temperature is 400-500 DEG C, and the calcination time is 2-3 h.
[0048] In step (1) of the preferred embodiment of the application, the calcination temperature is 400-500 DEG C, and the calcination time is 2-3 h.
[0049] In step (1) of the preferred embodiment of the application, when the calcination temperature is lower than 400 DEG C, V2O5 and g-C3N4 are only combined by physical adsorption, there is a lack of chemical bonds at the interface, the electron transmission resistance is large, and it is difficult for photo-generated electrons to be effectively injected into the V 5+ sites of V2O5. When the calcination temperature exceeds 500 DEG C, the triazine ring structure of g-C3N4 begins to decompose, nitrogen atoms escape to form defects, and the light absorption capacity decreases; at the same time, V2O5 may melt and agglomerate to form an amorphous phase, losing the reversible electron storage capacity.
[0050] In step (2) of the preferred embodiment of the present application, the calcination temperature is 300-350℃, and the calcination time is 1-3h.
[0051] In step (2) of the preferred embodiment of the present application, the heating rate of calcination is 2-4℃ / min, and the gas atmosphere is inert gas.
[0052] In step (2) of the preferred embodiment of the present application, when the calcination temperature is lower than 300℃, the functional groups on the surface of MXene (such as -OH) are not fully activated, and the chemical bonding force with g-C3N4 / V2O5 is weak, which is easy to fall off in the catalytic process; when the temperature exceeds 350℃, although the inert gas atmosphere can prevent the oxidation of MXene, the interlayer metal bond (such as Ti-C) will be broken due to high temperature, resulting in the collapse of the sheet structure and the decrease of conductivity.
[0053] The technical solutions of the present application are further illustrated by the following examples.
[0054] Example 1
[0055] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0056] (1) Mix and grind g-C3N4 and V2O5 powders, then place the mixture in a tube furnace for calcination, wherein the mass fraction of V2O5 relative to g-C3N4 is 7%, the calcination temperature is 500℃, the calcination time is 2h, the heating rate is 5℃ / min, and the gas atmosphere is air, to obtain a g-C3N4 / V2O5 composite catalyst (referred to as 7.0VC);
[0057] (2) Mix the 7.0VC obtained in step (1) with MXene material uniformly, and place it in a tube furnace for calcination at 350℃ under nitrogen atmosphere protection for 2h, wherein the heating rate is 2℃ / min, and the mass fraction of MXene material relative to g-C3N4 is 3%, to obtain a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance (referred to as VCT-3, wherein 3 is the mass fraction of MXene relative to g-C3N4, the same below).
[0058] Example 2
[0059] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0060] (1) The preparation method of g-C3N4 / V2O5 composite catalyst is the same as that of Example 1;
[0061] (2) The 7.0VC obtained in step (1) is mixed uniformly with MXene material, and is placed in a tube furnace and calcined at 350°C for 2h under the protection of a nitrogen atmosphere, wherein the heating rate is 2°C / min, the mass fraction of MXene material relative to g-C3N4 is 5%, and a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance (referred to as VCT-5) is obtained.
[0062] Example 3
[0063] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0064] (1) The g-C3N4 / V2O5 composite catalyst preparation method is the same as that in Example 1;
[0065] (2) The 7.0VC obtained in step (1) is mixed uniformly with MXene material, and is placed in a tube furnace and calcined at 350°C for 2h under the protection of a nitrogen atmosphere, wherein the heating rate is 2°C / min, the mass fraction of MXene material relative to g-C3N4 is 7%, and a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance (referred to as VCT-7) is obtained.
[0066] Example 4
[0067] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0068] (1) g-C3N4 and V2O5 powders are mixed and ground, and then the mixture is placed in a tube furnace for calcination, wherein the mass fraction of V2O5 relative to g-C3N4 is 2%, the calcination temperature is 500°C, the calcination time is 2h, the heating rate is 5°C / min, and the gas atmosphere is air, to obtain a g-C3N4 / V2O5 composite catalyst (referred to as 2.0VC);
[0069] (2) The 2.0VC obtained in step (1) is mixed uniformly with MXene material, and is placed in a tube furnace and calcined at 350°C for 2h under the protection of a nitrogen atmosphere, wherein the heating rate is 2°C / min, the mass fraction of MXene material relative to g-C3N4 is 7%, and a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance is obtained.
[0070] Example 5
[0071] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0072] (1) g-C3N4 and V2O5 powders are mixed and ground, and then the mixture is placed in a tube furnace for calcination, wherein the mass fraction of V2O5 relative to g-C3N4 is 5%, the calcination temperature is 500°C, the calcination time is 2h, the heating rate is 5°C / min, and the gas atmosphere is air, to obtain a g-C3N4 / V2O5 composite catalyst (referred to as 5.0VC);
[0073] (2) The 5.0VC obtained in step (1) is uniformly mixed with MXene material, and is placed in a tube furnace for calcination under the protection of a nitrogen atmosphere at 350°C for 2h, wherein the heating rate is 2°C / min, and the mass fraction of MXene material relative to g-C3N4 is 7%, to obtain a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance.
[0074] Example 6
[0075] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0076] (1) g-C3N4 and V2O5 powders are mixed and ground, and then the mixture is placed in a tube furnace for calcination, wherein the mass fraction of V2O5 relative to g-C3N4 is 10%, the calcination temperature is 500°C, the calcination time is 2h, the heating rate is 5°C / min, and the gas atmosphere is air, to obtain a g-C3N4 / V2O5 composite catalyst (referred to as 10.0VC);
[0077] (2) The 10.0VC obtained in step (1) is uniformly mixed with MXene material, and is placed in a tube furnace for calcination under the protection of a nitrogen atmosphere at 350°C for 2h, wherein the heating rate is 2°C / min, and the mass fraction of MXene material relative to g-C3N4 is 7%, to obtain a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance.
[0078] Example 7
[0079] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0080] (1) g-C3N4 and V2O5 powders are mixed and ground, and then the mixture is placed in a tube furnace for calcination, wherein the mass fraction of V2O5 relative to g-C3N4 is 7%, the calcination temperature is 400°C, the calcination time is 3h, the heating rate is 4°C / min, and the gas atmosphere is air, to obtain a g-C3N4 / V2O5 composite catalyst (7.0VC);
[0081] (2) The 7.0VC obtained in step (1) is mixed uniformly with MXene material, and is placed in a tube furnace and calcined at 300°C for 3h under the protection of argon atmosphere, wherein the heating rate is 4°C / min, the mass fraction of MXene material relative to g-C3N4 is 3%, and a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance is obtained.
[0082] Example 8
[0083] A preparation method of a graphite phase carbon nitride composite catalyst (g-C3N4 / V2O5 / Mxene) with light-dark continuous catalytic performance, comprising the following steps:
[0084] (1) g-C3N4 and V2O5 powders are mixed and ground, and then the mixture is placed in a tube furnace for calcination, wherein the mass fraction of V2O5 relative to g-C3N4 is 7%, the calcination temperature is 500°C, the calcination time is 2h, the heating rate is 6°C / min, and the gas atmosphere is air, to obtain a g-C3N4 / V2O5 composite catalyst;
[0085] (2) The 7.0VC obtained in step (1) is mixed uniformly with MXene material, and is placed in a tube furnace and calcined at 330°C for 1h under the protection of argon atmosphere, wherein the heating rate is 2°C / min, the mass fraction of MXene material relative to g-C3N4 is 3%, and a graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance is obtained.
[0086] Comparative Example 1
[0087] g-C3N4 is placed in a tube furnace for calcination, the calcination temperature is 500°C, the calcination time is 2h, the heating rate is 5°C / min, and the gas atmosphere is air, and then it is placed in a tube furnace and calcined at 350°C for 2h under the protection of nitrogen atmosphere, wherein the heating rate is 2°C / min, to obtain a g-C3N4 catalyst.
[0088] Comparative Example 2
[0089] The same as Example 1, except that the addition of V2O5 is omitted, comprising the following steps:
[0090] (1) g-C3N4 is placed in a tube furnace for calcination, the calcination temperature is 500°C, the calcination time is 2h, the heating rate is 5°C / min, and the gas atmosphere is air, to obtain a g-C3N4 catalyst;
[0091] (2) The g-C3N4 catalyst obtained in step (1) is mixed with MXene material uniformly, and is placed in a tube furnace and calcined at 350°C for 2h under nitrogen atmosphere protection, wherein the temperature rising rate is 2°C / min, the mass fraction of MXene material relative to g-C3N4 is 3%, to obtain a graphite phase carbon nitride composite catalyst (g-C3N4 / MXene).
[0092] Comparative Example 3
[0093] The same as Example 1, except that in step (1), the mass fraction of V2O5 relative to g-C3N4 is 15%.
[0094] Comparative Example 4
[0095] The same as Example 1, except that in step (2), the mass fraction of MXene material relative to g-C3N4 is 20%.
[0096] Comparative Example 5
[0097] The same as Example 1, except that in step (1), the calcination temperature is 800°C.
[0098] Comparative Example 6
[0099] The same as Example 1, except that in step (2), the calcination temperature is 600°C.
[0100] Performance test
[0101] First, 20 mg of catalyst is placed in 50 mL of water, and is placed under visible light source (λ≥420 nm) for 2h, then the light source is turned off and a certain amount of tetracycline hydrochloride is placed in the above composite catalyst aqueous solution, so that the tetracycline hydrochloride concentration is 20 mg / L, the reaction starts, every certain time at the maximum absorption wavelength (λ=357 nm) of tetracycline hydrochloride, the absorbance value is determined, and the degradation rate of tetracycline hydrochloride in the reaction process is calculated.
[0102] The degradation rate of tetracycline hydrochloride in the dark state of the graphite phase carbon nitride composite catalyst prepared in Examples 1-8 and the g-C3N4 catalyst in Comparative Example 1 is shown in Table 1. Figure 1As can be seen, with the increase of the amount of V2O5, the degradation rate of tetracycline hydrochloride by the composite catalyst under dark conditions increased significantly. When the amount of V2O5 was 7% and the amount of MXene was 5%, the degradation rate of tetracycline hydrochloride reached the highest value of 68% in 120 min. This shows that V2O5 has energy storage function, and MXene can further promote electron transfer and promote the dark state catalytic performance of graphite phase carbon nitride. In addition, with the increase of the amount of MXene, the degradation rate of tetracycline hydrochloride by graphite phase carbon nitride composite catalyst under dark conditions increased significantly. When the amount of MXene was 5%, the degradation rate of tetracycline hydrochloride reached the highest value of 68% in 120 min. This means that MXene can further promote the catalytic oxidation performance of the composite catalyst. It is worth noting that changing the preparation temperature of g-C3N4 / V2O5 and MXene / g-C3N4 / V2O5 can significantly affect the dark state catalytic performance of the catalyst. Therefore, the preparation conditions of the catalyst can be adjusted according to different application scenarios to achieve the desired effect.
[0103] Figure 2 The degradation rate of tetracycline hydrochloride by the catalyst prepared in Example 2 and Comparative Examples 1-6 under dark conditions was shown. The results showed that the degradation rate of tetracycline hydrochloride by g-C3N4 was only 20%, and after adding MXene, the degradation rate of tetracycline hydrochloride by the catalyst (MXene / g-C3N4) was about 20%. This shows that the addition of MXene alone does not significantly improve the dark state catalytic effect of the catalyst, which means that MXene does not have significant energy storage performance. In addition, increasing the amount of V2O5 can improve the dark state catalytic performance of the catalyst. However, excessive MXene can inhibit the catalytic performance of the catalyst.
[0104] The results of hydroxyl radical determination of graphite phase carbon nitride composite catalyst (VCT-5) prepared in Example 2 are shown in Figure 3 , and the results of superoxide radical determination are shown in Figure 4 As can be seen, VCT-5 catalyst has significant hydroxyl radical and superoxide radical peaks under light and dark conditions, which shows that the composite catalyst can generate free radicals with strong oxidation performance under light and dark conditions.
[0105] The cyclic voltammetry curve of graphite phase carbon nitride composite catalyst (VCT-5) prepared in Example 2 is shown in Figure 5 As can be seen, the capacitance of the catalyst without light treatment is only 16.6 F·cm -1 ; after light treatment, the capacitance of the composite catalyst increased significantly to 20.3 F·cm -1 , which is the process of charging the micro proton battery; after light treatment for 2 h and then dark oxidation degradation of pollutants for 2 h, the capacitance of the composite catalyst decreased slowly (18.5 F·cm -1), which is the process of micro proton battery discharge, indicating that the composite catalyst system with micro proton battery structure and light-dark continuous catalytic performance is successfully constructed.
[0106] The above merely provides the preferred embodiment of the present application, and the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or replacements within the technical scope disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A graphite phase carbon nitride composite catalyst having photo-dark continuous catalytic performance, characterized in that, The raw materials include graphite phase carbon nitride, vanadium pentoxide and MXene material, the vanadium pentoxide accounts for 2-10% of the mass of the graphite phase carbon nitride, and the MXene material accounts for 3-7% of the mass of the graphite phase carbon nitride; The preparation method of the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance comprises the following steps: (1) The graphite phase carbon nitride and vanadium pentoxide powder are mixed and ground, and first calcination is performed to obtain a g-C3N4 / V2O5 composite catalyst; (2) The g-C3N4 / V2O5 composite catalyst is uniformly mixed with the MXene material, and second calcination is performed to obtain the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance; The temperature of the first calcination is 400-500 DEG C, and the calcination time is 2-3h; The temperature of the second calcination is 300-350 DEG C, and the calcination time is 1-3h.
2. A method for preparing the graphite phase carbon nitride composite catalyst having photo-dark continuous catalytic performance according to claim 1, characterized by, The preparation method of the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance comprises the following steps: (1) The graphite phase carbon nitride and vanadium pentoxide powder are mixed and ground, and first calcination is performed to obtain a g-C3N4 / V2O5 composite catalyst; (2) The g-C3N4 / V2O5 composite catalyst is uniformly mixed with the MXene material, and second calcination is performed to obtain the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance; The temperature of the first calcination is 400-500 DEG C, and the calcination time is 2-3h; The temperature of the second calcination is 300-350 DEG C, and the calcination time is 1-3h.
3. The method of claim 2, wherein the preparation of the graphite phase carbon nitride composite catalyst having photo-dark continuous catalytic performance is characterized by, The heating rate of the first calcination is 4-6 DEG C / min, and the gas atmosphere is air.
4. The method of claim 2, wherein the preparation of the graphite phase carbon nitride composite catalyst having photo-dark continuous catalytic performance is characterized by, The heating rate of the second calcination is 2-4 DEG C / min, and the gas atmosphere is inert gas.
5. The graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance according to claim 1 is used for degrading antibiotics in water.
6. The use of the graphite phase carbon nitride composite catalyst with photo-dark continuous catalytic performance according to claim 5 for degrading antibiotics in water bodies, characterized in that, The graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance degrades antibiotics in water under light-dark alternating conditions.
7. The use of the graphite phase carbon nitride composite catalyst with photo-dark continuous catalytic performance in the degradation of antibiotics in water bodies according to claim 5, characterized in that, The addition amount of the graphite phase carbon nitride composite catalyst with light-dark continuous catalytic performance in water is 4mg / 10mL.
8. The use of the graphite phase carbon nitride composite catalyst with photo-dark continuous catalytic performance in claim 5 for degrading antibiotics in water bodies, characterized by, The concentration of the antibiotics in the water is 20mg / L.