Ternary nano composite material as well as preparation method and application thereof

Abstract

The invention discloses a ternary nano composite material and a preparation method and application thereof, and the preparation method of the ternary nano composite material comprises the following steps: S1, preparing a titanium mesh distributed with anatase type titanium dioxide nanotubes; and S2, mixing and grinding melamine and titanium carbide, and carrying out chemical vapor deposition on the obtained mixture on a titanium mesh on which the anatase type titanium dioxide nanotubes are distributed, so as to obtain the ternary nano composite material with a three-dimensional network structure. The composite material is excellent in photocatalytic performance, high in chemical stability, environment-friendly, simple in preparation method, low in cost, capable of being applied to catalytic degradation of water bodies containing organic pollutants, high in degradation efficiency, capable of being repeatedly utilized and free of secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of composite materials, and in particular to a ternary nanocomposite material, its preparation method, and its application. Background Technology

[0002] With the accelerating pace of technological and social development, the economic scale accumulated by humankind in the last few decades has surpassed the total development of the previous millennia. People's living standards have also improved significantly. However, behind this convenient lifestyle, resource consumption has increased dramatically. Reckless environmental destruction and neglect of resource scarcity have exacerbated environmental pollution. Currently, many factories are discharging pollutants that fail to meet standards or exceed emission limits. These pollutants are primarily organic, many of which are complex in composition, high in concentration, and difficult to degrade, far exceeding the self-purification capacity of the ecosystem. Furthermore, through bioaccumulation and transmission in the food chain, these harmful substances can easily enter the human body, posing a significant threat to health. Since their invention, antibiotics have been crucial for protecting human health. However, the unrestricted use of antibiotics has led to a rapid increase in their levels in the environment, damaging water sources essential for human survival. Current methods for treating these organic pollutants mainly involve physicochemical and biological methods. While these methods have some effectiveness in removing pollutants, they are difficult to completely remove or convert into harmless products, and the impact of subsequent chemical treatments and operating costs are difficult to estimate. Trace amounts of residual antibiotics in water bodies stimulate pathogen mutations and gradually lead to drug resistance, posing a threat to human health. Due to the massive volume of wastewater discharge and inadequate treatment technologies, antibiotic wastewater and dye wastewater have become urgent problems to be solved. Scholars have conducted in-depth research on solutions to these pollution problems. Photocatalysis, as a rapidly developing environmental protection technology, works by using photocatalytic materials as carriers under light conditions to convert absorbed light energy into other forms of energy. It possesses both good oxidizing and reducing properties, demonstrating unique advantages in the removal of organic pollutants. In water treatment, this technology can generate free radicals that decompose pollutants in wastewater into non-polluting intermediates and even smaller molecules. As a novel environmentally friendly oxidation technology, photocatalysis is simple to operate and produces almost no secondary pollution, playing a crucial role in current environmental governance. However, conventional chemical oxidation technologies and mono- and binary photocatalytic materials generally suffer from slow electron migration rates and high electron-hole recombination rates. Therefore, the development of new photocatalytic materials remains a research hotspot in this field.

[0003] Chinese patent CN103628111B discloses a method for preparing TiO2 nanotube arrays on a large-area Ti mesh. The method directly uses a metal tank as the counter electrode to construct a two-electrode anodic oxidation system, with a surface-cleaned large-area Ti mesh serving as the anode. Anodizing is performed for a certain time in an F-containing electrolyte, resulting in a uniform and ordered TiO2 nanotube array on the Ti mesh surface. This method can prepare large-sized TiO2 nanotube array / Ti mesh composite nanomaterials. The resulting materials possess advantages such as large specific surface area and high surface activity, while also exhibiting filterability. They demonstrate outstanding performance and application advantages in photocatalysis, solar cells, and sensors. Furthermore, the process is simple, allows for mass production, and is suitable for industrial production and applications.

[0004] Chinese patent application CN108970633A discloses a g-C3N4 nanosheet-modified TiO2 nanotube array and its preparation method. The array consists of finely dispersed g-C3N4 nanosheets uniformly distributed within the TiO2 nanotube array. This method obtains the g-C3N4 nanosheet-modified TiO2 nanotube array by vapor deposition of g-C3N4 nanosheets onto the surface of a TiO2 nanotube array prepared by anodic oxidation. Compared to g-C3N4 / TiO2 composite nanotube arrays prepared by other methods, the vapor-deposited g-C3N4 nanosheets are smaller, exhibit better contact and bonding with the TiO2 nanotubes, are less prone to detachment, and are uniformly distributed. This improves the photoelectrochemical performance of the TiO2 nanotube array under ultraviolet light irradiation and broadens its spectral response range, making it effective for applications in photoelectrocatalysis and photoelectrochemical detection technologies. However, the effectiveness of the g-C3N4 nanosheet-modified TiO2 nanotube array prepared by this method in degrading organic pollutants needs further improvement. Summary of the Invention

[0005] The present invention aims to provide a ternary nanocomposite material and its preparation method. The obtained ternary nanocomposite material has excellent degradation effect on organic pollutants and good recycling performance.

[0006] This invention also provides an application of ternary nanocomposite materials in the photocatalytic degradation of water containing organic pollutants.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a ternary nanocomposite material includes S1, preparing a titanium mesh with anatase titanium dioxide nanotubes distributed thereon, and further includes the following steps:

[0009] S2. Melamine and titanium carbide are mixed and ground. The resulting mixture is then subjected to chemical vapor deposition on a titanium mesh on which anatase titanium dioxide nanotubes are distributed to obtain a ternary nanocomposite material with a three-dimensional network structure.

[0010] The experimental results in Abdurahman MH, Li JH, Abdullah AZ, Liu QQ. Multi-staged carrier transfer in a ternary Bi2S3 / Ti3C2-MXene@g-C3N4 heterojunction for enhanced photocatalytic degradation of tetracycline: Performance and mechanism insights[J]. Ceramics International, 2025, 51: 35816-35827. DOI: 10.1016 / j.ceramint.2025.05.304. demonstrate that Ti3C2 cannot act as a highly efficient photocatalyst independently, and that Ti3C2 has limited effect on improving the photocatalytic performance of g-C3N4.

[0011] Liu QR, Ma F, Tan XY, Znad H, Liu LH, Wang SB, Shen ZF, Liu S M. MXene as a non-metal charge mediator in 2D layered CdS@Ti3C2@TiO2 composites with superior Z-scheme visible light-driven photocatalytic activity[J]. Environ. Sci.: Nano, 2019, 6: 3158-3169. DOI: 10.1039 / c9en00567f. Experimental results demonstrate that Ti3C2 cannot function as a high-efficiency photocatalyst independently, and the photocatalytic performance of Ti3C2 / TiO2 is also poor.

[0012] The g-C3N4 / Ti3C2 / TiO2 ternary nanocomposite material prepared in this invention has a significantly higher removal efficiency for RhB and tetracycline hydrochloride than the C3N4 / TiO2 nanotube array TCN0. This indicates that Ti3C2 plays an important role as an electron transport bridge in this invention, which can significantly improve the removal efficiency of RhB and tetracycline hydrochloride by the nanocomposite material.

[0013] In this invention, g-C3N4 / TiO2 nanotube array binary composites and g-C3N4 / Ti3C2 / TiO2 nanotube array ternary composites were prepared on a titanium mesh substrate by chemical vapor deposition. Compared with template methods, impregnation methods, and electrolyte methods, no special templates are required, the operation process is simple, no external electric field is applied, and the cost is relatively low.

[0014] Chemical vapor deposition (CVD) directly utilizes titanium mesh as both the titanium source and substrate, constructing TiO2 nanotube arrays in situ via vapor-phase reaction. This simplifies the process, reduces energy consumption, and is more suitable for large-scale fabrication. Titanium mesh possesses high specific surface area, good electrical conductivity, mechanical flexibility, and permeability, providing a stable and efficient three-dimensional support platform for TiO2 nanotube arrays. The in-situ grown nanotube array exhibits regular orientation, high specific surface area, and excellent photoelectric properties, facilitating rapid transport of photogenerated carriers and enhancing surface reactivity. Subsequent steps introduce g-C3N4 and Ti3C2 to achieve uniform composite formation of multiple components on the nanotube array, avoiding the complexity of multi-step liquid-phase processing and improving the controllability and reproducibility of the composite structure.

[0015] According to embodiments of the present invention, the present invention can be further optimized, and the optimized technical solution is as follows:

[0016] In step S2, the mass ratio of melamine to titanium carbide is 10 to 40:1, preferably 10 to 20:1.

[0017] The mass of melamine is 1~4g, preferably 2~4g.

[0018] Based on the amount of titanium carbide used, the prepared composite photocatalytic materials were named TCN1 (10:1), TCN2 (20:1), and TCN3 (40:1), respectively. This parameter range is a suitable ratio for achieving the high-performance ternary synergistic effect of g-C3N4 / Ti3C2 / TiO2. Within this range (TCN1, TCN2, TCN3), the composite materials exhibited photocatalytic performance far exceeding that of the binary composite material (TCN0) and pure TiO2. Specifically, the effect is reflected in the formation of an ideal heterojunction structure: an appropriate amount of Ti3C2 (relative to melamine) can act as both a "skeleton" or "template" for the formation of g-C3N4 during chemical vapor deposition, influencing its morphology and dispersion, and can also maintain part of its own structure under a high-temperature nitrogen atmosphere, serving as an efficient electron transport bridge connecting g-C3N4 and TiO2, accelerating the separation and migration of photogenerated carriers. PL and LSV data confirm this. Optimal photocatalytic activity was achieved: Experimental data showed that at this ratio, especially with TCN1 at a ratio of 10:1, the degradation efficiency for RhB and TC-HCl reached its peak (96.04% and 85.12%, respectively). This indicates that the ternary heterojunction formed at this ratio achieved an optimal balance in the three core processes of light absorption, charge separation, and surface reaction.

[0019] However, Ti3C2 should not be used in excess. Excessive Ti3C2 can lead to: 1) uncontrollable stacking, agglomeration, and even over-oxidation during high-temperature processes. Agglomerated Ti3C2 can block the openings and pores of TiO2 nanotubes, reducing the specific surface area and reaction sites of the material. 2) Too much Ti3C2 may not be able to form a uniform and tight interfacial contact with g-C3N4 and TiO2. Some Ti3C2 may become isolated and ineffective "dead zones," instead becoming recombination centers for electron-hole pairs. 3) Excessive Ti3C2 may excessively shield the light absorption of TiO2 and g-C3N4. At the same time, if its own metallic conductivity becomes excessively dominant, it will destroy the band structure advantage of the heterojunction, resulting in a decrease in the photogenerated carrier separation efficiency instead of an increase.

[0020] In one preferred embodiment, the grinding time in step S2 is 20 min to 30 min.

[0021] In one preferred embodiment, the calcination temperature of the chemical vapor deposition is 500°C to 550°C, the calcination time is 2h to 3h, the heating rate during the calcination process is 3°C / min to 5°C / min, and the calcination is carried out under a nitrogen atmosphere.

[0022] In one preferred embodiment, in step S2, before performing the chemical vapor deposition, a quartz boat is prepared, and 30% to 50% by mass of the mixture is placed on the bottom surface of the quartz boat. The titanium mesh with anatase titanium dioxide nanotubes distributed in step S2 is placed inside the quartz boat, and 50% to 70% by mass of the mixture is placed on the titanium mesh with anatase titanium dioxide nanotubes distributed in it. Then, the resulting quartz boat is wrapped with aluminum foil, small holes are made in the aluminum foil, and then chemical vapor deposition is performed.

[0023] A titanium mesh containing anatase titanium dioxide nanotubes, prepared in step S1, is placed inside a quartz boat at a distance of 0.3 to 0.5 cm from its bottom surface.

[0024] In one preferred embodiment, in step S1, a titanium mesh is immersed in an electrolyte composed of sodium fluoride, sodium bisulfate, and water. Using the titanium mesh as the working electrode and Pt as the counter electrode, an anodic oxidation reaction is performed, forming several titanium dioxide nanotubes along both the radial and axial directions on the titanium wire. The titanium dioxide nanotubes grow radially along the titanium wire. After cleaning and drying, the nanotubes are calcined to transform the crystal form of the titanium dioxide nanotubes into anatase, resulting in a titanium mesh with anatase-type titanium dioxide nanotubes distributed on it.

[0025] In one preferred embodiment, in step S1, the titanium mesh is pretreated before being immersed in the electrolyte: the titanium mesh is immersed in hydrofluoric acid solution for 3 to 5 seconds, then washed with ultrapure water more than 3 times, dried, and the dried titanium mesh is degreased by washing with acetone, ethanol and water for more than 15 minutes respectively, thus completing the pretreatment. In the hydrofluoric acid solution, the volume ratio of hydrofluoric acid to water is 1 to 3: 1 to 3.

[0026] In step S1, the calcination temperature is 550℃~600℃, and the calcination is carried out under a nitrogen atmosphere for 2~3 hours with a heating rate of 3~5℃ / min.

[0027] In step S1, after the anodizing reaction, a titanium mesh containing a titanium dioxide nanotube array is placed in ethylene glycol and ultrasonically cleaned for 300-600 seconds with stirring to remove the disordered filamentous film formed on the outer surface of the titanium dioxide nanotubes during anodizing, and then dried at 70-80°C.

[0028] In step S1, the mass fraction of sodium fluoride in the electrolyte is 0.4% to 0.5%, the mass fraction of sodium bisulfate in the electrolyte is 6.5% to 7.0%, the voltage of the anodic oxidation reaction is 20V to 30V, the time of the anodic oxidation reaction is 2h to 3h, the calcination temperature is 500℃ to 550℃, the calcination time is 2h to 3h, and the heating rate during the calcination process is 3℃ / min to 5℃ / min.

[0029] In step S2, the titanium carbide is prepared by mixing aluminum titanium carbide with hydrofluoric acid solution, stirring, centrifuging and washing, and vacuum drying to obtain titanium carbide. The mass-to-volume ratio of aluminum titanium carbide to hydrofluoric acid solution is 1g-4g:40mL-160mL, and the volume ratio of hydrofluoric acid to water in the hydrofluoric acid solution is 0.5-1:1.

[0030] The present invention also discloses a ternary nanocomposite material, wherein the ternary nanocomposite material uses a titanium mesh as a matrix, and titanium dioxide nanotubes are distributed on the titanium mesh. The walls of the titanium dioxide nanotubes are modified with graphitic carbon nitride and titanium carbide, and the titanium dioxide nanotubes are anatase titanium dioxide nanotubes.

[0031] In one preferred embodiment, the ternary nanocomposite material has a three-dimensional network structure, and the titanium dioxide nanotubes distributed on the titanium network are arranged in a honeycomb pattern. The titanium dioxide nanotubes modified with graphitic carbon nitride and titanium carbide are attached to the inner wall of the titanium dioxide nanotube array in a leaf shape.

[0032] The titanium mesh is made of titanium wires, on which several titanium dioxide nanotubes are distributed radially and axially, and the titanium dioxide nanotubes grow radially along the titanium wires.

[0033] Specifically, in one embodiment, the ternary nanocomposite material has a length of 1.5cm to 3.0cm, a width of 1.0cm to 2.0cm, and the volume of the organic pollutant is 45mL to 50mL.

[0034] The present invention also discloses the application of the ternary nanocomposite material as described above or the ternary nanocomposite material prepared by the preparation method described above in the photocatalytic degradation of water containing organic pollutants; preferably, the application includes the following steps: adding the ternary nanocomposite material to water containing organic pollutants, and degrading the organic pollutants under visible light irradiation.

[0035] More preferably, the organic pollutant is rhodamine B or tetracycline hydrochloride, wherein the concentration of rhodamine B is 10 mg / L to 15 mg / L, and the concentration of tetracycline hydrochloride is 10 mg / L to 15 mg / L.

[0036] This invention eliminates the need for the addition of Refenton's reagent, enabling photocatalytic degradation of water containing organic pollutants directly under visible light irradiation. Preferably, the temperature is room temperature, and the light conditions are a xenon lamp source (wavelength greater than 450 nm, irradiation time 0.5h-2h).

[0037] This invention prepares g-C3N4 / TiO2 nanotube array binary composites and g-C3N4 / Ti3C2 / TiO2 nanotube array ternary composites on a titanium mesh substrate via chemical vapor deposition. Compared to template methods, impregnation methods, and electrolyte methods, this method requires no special template, simplifies the operation, eliminates the need for an external electric field, and has relatively low cost. Nano-TiO2 has received significant attention in areas such as photocatalytic water splitting and the removal of harmful substances from soil and wastewater. However, this material is still limited by its wide bandgap (3.2 eV), exhibiting photoresponse only under ultraviolet light, thus limiting its application range and resulting in high energy consumption. g-C3N4, with its narrow bandgap, has a large visible light response range in sunlight. Therefore, coupling the two can expand the visible light absorption range of TiO2 and increase the utilization rate of green energy. However, g-C3N4 still suffers from drawbacks such as a high electron-hole recombination rate and low specific surface area, inhibiting its practical application. Ti3C2, due to its excellent conductivity, has already found important applications in energy storage. Therefore, this technology mainly utilizes the properties of g-C3N4 and Ti3C2 materials to synthesize three-dimensional composite materials, thereby increasing the degradation efficiency and recyclability of pollutants in aquatic environments. Multiple characterization results show that the complexes of g-C3N4 and Ti3C2 are uniformly distributed on the surface of the TiO2 nanotube array, forming a heterostructure that effectively reduces the recombination rate of electron-hole pairs. When the photocatalyst is irradiated by a visible light source, photons are absorbed and electrons are excited on the VB of g-C3N4 and TiO2. Simultaneously, electrons on the CB of g-C3N4 move to the CB of TiO2, thereby capturing O2 attached to the material surface and reacting to generate bio-superoxide radicals, which are the main free radicals in the degradation of pollutants. The h remaining in the VB of TiO2... + It will move into the VB of g-C3N4 and readily react with H2O in solution to form ·OH. The h in the valence band of g-C3N4 + The ·OH radicals, which act as auxiliary oxidants, can decompose pollutants into smaller intermediate molecules or directly oxidize them into final products (CO2 and H2O). In this process, Ti3C2 can act as a charge transport bridge, partially accepting electrons from the CB of g-C3N4 and the h from the VB of TiO2. + This is to further increase the separation rate of photogenerated carriers.

[0038] Furthermore, existing photocatalysts often exhibit poor reusability due to their inherent instability and limited catalytic sites. In contrast, the TCN1 in this invention showed almost no decrease in degradation efficiency for Rhodamine B after five cycles, demonstrating excellent chemical stability. The multi-component material, with a titanium mesh matrix, offers advantages over TiO2 powder materials in terms of ease of recycling and reuse, and also reduces the cost of pollutant degradation. Therefore, it has good application potential in the degradation of recalcitrant organic pollutants.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] (1) This invention provides a ternary nanocomposite material, which is the first in-situ synthesis of a g-C3N4 / Ti3C2 / TiO2 nanotube array ternary composite photocatalytic material on a titanium mesh. This invention generates several TiO2 nanotubes radially and axially on titanium wires, and modifies the walls of the TiO2 nanotubes with graphitic carbon nitride and titanium carbide, resulting in a three-dimensional network structure. By constructing a three-dimensional heterostructure on the TiO2 nanotubes arranged around the titanium wires, the light absorption range of TiO2 is expanded to achieve high quantum efficiency, significantly reducing the electron-hole recombination rate and thus greatly improving the photocatalytic performance. The synergistic use of TiO2 nanotube arrays, g-C3N4, and Ti3C2 in this invention not only expands the visible light absorption range of the composite photocatalytic material but also significantly improves electronic conductivity and carrier transport efficiency. The good conductivity of this material further enhances its photocatalytic performance. The network structure of the material also increases the contact area with pollutants while wastewater passes through, increasing the removal effect and providing aesthetic appeal during installation and application. The matrix material used in this invention is a titanium mesh. A three-dimensional TiO2 nanotube distribution can be formed on a single titanium wire. This three-dimensional form is mainly characterized by the growth of nanotubes around the radial and axial directions of the titanium wire, exhibiting a honeycomb-like arrangement. Furthermore, the graphitic carbon nitride and titanium carbide have an intercalated arrangement. Compared to two-dimensional planar nanotube arrays, the surrounding three-dimensional structure can provide more active sites during pollutant degradation, resulting in a larger contact area with pollutants and significantly improving pollutant removal efficiency. Therefore, the composite photocatalytic material of this invention has stronger photocatalytic activity and higher application value. The composite photocatalytic material of this invention has a simple preparation process, excellent chemical stability, low cost, is non-toxic and harmless, and is easy to recycle. Simultaneously, the mesh structure of the titanium mesh does not obstruct water flow and increases the contact area between pollutants and the surface of the photocatalytic material, resulting in excellent photocatalytic performance and a wide range of application prospects.

[0041] (2) This invention synthesizes ternary composite materials via chemical vapor deposition. The reactants are vaporized in a tube furnace at a suitable temperature to form volatile substances, which gradually move towards the deposition region. A chemical reaction occurs in this region, producing solid substances. Compared to traditional impregnation, electrolysis, and coating methods, this preparation process involves fewer steps, is simpler to operate, and has lower costs. It is beneficial for the preparation of photocatalytic composite materials, especially suitable for loading various materials, and the resulting heterostructure exhibits stronger stability and superior photocatalytic performance. The raw materials used in the preparation method of this invention are inexpensive and readily available, with broad application prospects, and have greater potential for promotion and application.

[0042] (3) This invention also provides the application of ternary nanocomposite materials in the photocatalytic degradation of water containing organic pollutants. The application steps are simple, the degradation efficiency is high, the materials can be reused multiple times, the materials are easy to recycle, and there is no secondary pollution. The ternary nanocomposite materials of this invention have excellent degradation performance on organic pollutants. They can degrade 96.05% of Rhodamine B within 90 min and 85.12% of Tetracycline Hydrochloride within 180 min. Compared with similar composite photocatalytic materials, such as g-C3N4 / TiO2 nanowire array materials synthesized on FTO conductive glass, g-C3N4 / TiO2 nanotube array materials synthesized on titanium sheets, and ultrathin g-C3N4 nanosheets / TiO2 nanotube array materials synthesized on titanium sheets, the degradation rate of Rhodamine B is increased by 30%, 90%, and 50%, respectively. This indicates that the composite photocatalytic materials of this invention have significantly enhanced removal efficiency for organic pollutants such as antibiotics and dyes in water and have a wider range of application prospects. Attached Figure Description

[0043] Figure 1 Figure 1 shows SEM images of a titanium mesh, anodized titanium mesh, an unmodified TiO2 nanotube array, and the ternary nanocomposite material prepared in Example 1 of this invention. Figure 2 shows the titanium mesh matrix, Figure 3 shows the anodized titanium mesh, Figure 4 shows the unmodified TiO2 nanotube array, and Figures 5 to 6 show the ternary nanocomposite material at different magnifications.

[0044] Figure 2 Figure 1 shows the elemental distribution of TiO2 nanotube array, single titanium wire, and ternary nanocomposite material prepared in Example 1 of this invention. Figure 1(a) shows TiO2 nanotube array, Figure 1(b) shows single titanium wire, and Figures 1(c) to 1(f) show the Ti, C, O, and N elements of ternary nanocomposite material.

[0045] Figure 3These are transmission electron microscope (TEM) images of the ternary nanocomposite material prepared in Example 1 of this invention, wherein Figures (a), (b), (c), and (d) are TEM images at resolutions of 0.2 μm, 100 nm, 0.2 μm, and 0.5 μm, respectively.

[0046] Figure 4 The images show the XRD patterns of the g-C3N4 / Ti3C2 / TiO2 nanotube array composite materials (TCN1, TCN2, TCN3), g-C3N4 / TiO2 nanotube array (TCN0), and overall network anatase TiO2 nanotube arrays (TNTAs) prepared in Examples 1, 2, and 3 of this invention.

[0047] Figure 5 The images show the FT-IR spectra of the g-C3N4 / Ti3C2 / TiO2 nanotube array composite materials (TCN1, TCN2, TCN3), g-C3N4 / TiO2 nanotube array (TCN0), and TiO2 nanotube array (TNTAs) prepared in Examples 1, 2, and 3 of this invention.

[0048] Figure 6 The images show the UV-Vis spectra of the g-C3N4 / Ti3C2 / TiO2 nanotube array composite materials (TCN1, TCN2, TCN3), g-C3N4 / TiO2 nanotube array (TCN0), and TiO2 nanotube array (TNTAs) prepared in Examples 1, 2, and 3 of this invention.

[0049] Figure 7 The images show the PL diagrams of the g-C3N4 / Ti3C2 / TiO2 nanotube array composite materials (TCN1, TCN2, TCN3), g-C3N4 / TiO2 nanotube array (TCN0), and TiO2 nanotube array (TNTAs) prepared in Examples 1, 2, and 3 of this invention.

[0050] Figure 8 The images show the degradation effects of the g-C3N4 / Ti3C2 / TiO2 nanotube array composite materials (TCN1, TCN2, TCN3), g-C3N4 / TiO2 nanotube array (TCN0), and TiO2 nanotube array (TNTAs) prepared in Examples 1, 2, and 3 of this invention on the organic pollutant Rhodamine B.

[0051] Figure 9 The images show the degradation effects of the g-C3N4 / Ti3C2 / TiO2 nanotube array composite materials (TCN1, TCN2, TCN3), g-C3N4 / TiO2 nanotube array (TCN0), and TiO2 nanotube array (TNTAs) prepared in Examples 1, 2, and 3 of this invention on the organic pollutant tetracycline hydrochloride.

[0052] Figure 10 The image shows the cyclic degradation effect of the g-C3N4 / Ti3C2 / TiO2 nanotube array composite material (TCN1) prepared in Example 1 of this invention on Rhodamine B. Detailed Implementation

[0053] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0054] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. In the following embodiments, unless otherwise specified, the raw materials and instruments used are commercially available, the raw materials are of analytical grade, and the data obtained are the average values ​​of three or more repeated experiments.

[0055] Example 1

[0056] A ternary nanocomposite material of the present invention uses a titanium mesh as a matrix. The titanium mesh is composed of titanium wires, and several titanium dioxide nanotubes are distributed on the titanium wires along both the radial and axial directions. The titanium dioxide nanotubes are modified with graphitic carbon nitride and titanium carbide. The titanium dioxide nanotubes are generated in situ by anodizing, and the graphitic carbon nitride and titanium carbide are obtained by thermal polymerization.

[0057] A method for preparing the ternary nanocomposite material described in this embodiment includes the following steps:

[0058] S1. Preparation of titanium carbide (Ti3C2)

[0059] 1g of titanium aluminum carbide (Ti3AlC2) powder was added to a polytetrafluoroethylene (PTFE) beaker containing 40mL of HF solution (HF to H2O volume ratio 1:1). The PTFE beaker was placed on a magnetic stirrer and stirred continuously at room temperature for 24 hours to selectively remove Al atoms from Ti3AlC2. The resulting reaction product was then centrifuged and washed multiple times with ethanol and deionized water until the pH value was approximately 7. The washed product was then placed in a vacuum constant temperature drying oven at 70°C for 6 hours to obtain Ti3C2 powder.

[0060] S2. Preparation of titanium dioxide nanotube arrays

[0061] A 0.30 mm thick, 1.5 cm × 1.0 cm Ti mesh (99.9%) was immersed in an aqueous solution of hydrofluoric acid for approximately 5 seconds, quickly removed, and washed repeatedly with deionized water at least three times. The volume ratio of hydrofluoric acid to deionized water in the hydrofluoric acid solution was 1:1. After drying in an oven, the dried titanium mesh was ultrasonically cleaned in acetone (C3H6O), ethanol (C2H6O), and deionized water (DI) for at least 15 minutes each to degrease it. The cleaned titanium mesh was then dried in a vacuum constant temperature drying oven at 80°C for 30 minutes. The dried titanium mesh was then placed in an electrolyte composed of sodium fluoride, sodium bisulfate, and water, with the Ti mesh as the working electrode and a Pt sheet as the counter electrode, and an anodizing reaction was carried out at 20 V for 2 hours at room temperature. The electrolyte consisted of 0.4 wt% NaF, 6.5 wt% NaHSO4, and deionized water. During anodizing, several titanium dioxide nanotubes are formed on the titanium wire both radially and axially. The titanium dioxide nanotubes grow radially along the titanium wire. Simultaneously, due to the oxide layer peeled off by chemical corrosion, a disordered filamentous structure film gradually forms on the outer surface of the nanotubes. To remove this film, the anodized titanium mesh needs to be ultrasonically cleaned in ethylene glycol for 300–600 seconds while maintaining slight stirring, and then dried at 70–80°C. After drying, the resulting material is placed in a tube furnace at 550°C and calcined for 2 hours under a nitrogen atmosphere at a heating rate of 3°C / min. At high temperature, the material gradually forms anatase titanium dioxide crystals, resulting in a titanium mesh with distributed anatase titanium dioxide nanotubes, denoted as TNTAs.

[0062] S3. Preparation of ternary nanocomposites

[0063] Melamine and Ti3C2 were mixed in a mass ratio of 10:1, with 4g of melamine. The mixture was added to an agate mortar and ground for at least 20 minutes to obtain a uniformly dispersed mixture. A quartz boat was prepared, and a titanium mesh containing anatase titanium dioxide nanotubes prepared in step (2) was placed about 0.3 cm from the bottom of the boat. The mixture was dispersed in two different locations, with 40% of the mixture placed at the bottom of the quartz boat and 60% of the mixture placed on the titanium mesh containing anatase titanium dioxide nanotubes. The quartz boat was tightly wrapped with aluminum foil, and 5 to 10 small holes were made at the front and back ends of the foil about 0.5 to 1.0 cm apart to allow nitrogen gas to pass through, which can increase the adhesion of the composite material. A quartz boat was placed in a tube furnace at 550℃ and calcined for 3 hours under nitrogen protection. During calcination, the mixture vaporized and deposited upwards. The calcination temperature rise rate was set to 5℃ / min. After calcination, a ternary nanocomposite material, namely a g-C3N4 / Ti3C2 / TiO2 nanotube array, was obtained, denoted as TCN1.

[0064] Example 2

[0065] The preparation method of the ternary nanocomposite material of the present invention is basically the same as that of Example 1, except that: in step (3), the mass ratio of melamine to Ti3C2 is 20:1, the mass of melamine is 2g, and the obtained ternary nanocomposite material is denoted as TCN2.

[0066] Example 3

[0067] The preparation method of the ternary nanocomposite material of the present invention is basically the same as that of Example 1, except that: in step (3), the mass ratio of melamine to Ti3C2 is 40:1, the mass of melamine is 1g, and the obtained ternary nanocomposite material is denoted as TCN3.

[0068] Comparative Example 1 g-C3N4 / TiO2 nanotube array (TCN0): The preparation process is the same as that of g-C3N4 / Ti3C2 / TiO2 in Example 1, but no Ti3C2 material is added during the grinding process.

[0069] Four grams of melamine precursor were added to an agate mortar and ground for at least 20 minutes. This melamine was then evenly distributed on the bottom of a quartz boat and on a TiO2 nanotube array mounted approximately 0.3 cm above it. During this process, the quartz boat was tightly wrapped entirely with aluminum foil, with several small holes made at the front and back ends to allow nitrogen gas to pass through. The nitrogen atmosphere increases the adhesion between different monomers in the composite material, forming a heterogeneous structure. The quartz boat was then placed in a tube furnace at 550°C for 3 hours, with a temperature rise rate set at 5°C / min. -1 .

[0070] Comparative Example 2g-C3N4

[0071] Melamine was calcined at 550°C in a tube furnace under nitrogen atmosphere for 3 hours, with the temperature rise rate set at 5°C / min. -1 .

[0072] The ternary nanocomposite materials prepared in the above embodiments were characterized, and a binary g-C3N4 / TiO2 nanotube array was used as a comparative experiment for characterization. The results are as follows: Figures 1 to 7 As shown.

[0073] Figure 1 Figures (a) and (b) show SEM images of various materials. Figure (a) is a large-area SEM image of the titanium mesh matrix, showing the basic structure of the titanium mesh. Figure (b) shows the SEM image of the surface of the titanium mesh after anodizing, indicating that multiple cracks appear on the surface of a single titanium wire, suggesting that the porous oxide layer on the surface of the titanium mesh has peeled off due to chemical corrosion. Figure (c) is a structural diagram of the unmodified TiO2 nanotube array, showing that there is no material load on the surface of the nanotube array. Figures (d) to (f) show SEM images of the ternary nanocomposite material prepared in Example 1 of this invention at different magnifications. It can be observed that each single titanium wire has several titanium dioxide nanotubes distributed radially and axially, and the titanium dioxide nanotubes almost cover the circumference of the titanium wire, exhibiting a honeycomb-like arrangement. The graphitic carbon nitride and titanium carbide are intercalated and can provide more active sites during the degradation of pollutants.

[0074] Figure 2 Figure 1 shows the elemental distribution of various materials. Figure 2(a) shows the TiO2 nanotube array, Figure 3(b) shows a single titanium wire, and Figures 4(c) to 5(f) show the elemental distribution of Ti, C, O and N in the ternary nanocomposite material of Example 1. The dotted distribution in the figure shows that Ti, C, O and N elements are uniformly distributed on the g-C3N4 / Ti3C2 / TiO2 nanotube array. The colors of Ti, C, O and N elements in the figure are blue, yellow, red and green, respectively.

[0075] Figure 3 These are TEM images of the ternary nanocomposite material prepared in Example 1 of this invention. Figures (a), (b), (c), and (d) are TEM images at resolutions of 0.2 μm, 100 nm, 0.2 μm, and 0.5 μm, respectively. The images show that the g-C3N4 and Ti3C2 composites are in close contact on the inner and outer tubes of the TiO2 nanotube array, indicating the formation of a heterostructure. An ordered arrangement of the TiO2 nanotube array is also visible.

[0076] Figure 4 The figures show the XRD patterns of the ternary nanocomposites (TCN1, TCN2, TCN3) prepared in Examples 1, 2, and 3 of this invention, the comparative experiment g-C3N4 / TiO2 nanotube array (TCN0), the titanium dioxide nanotube array (TNTAs), Ti3AlC2, Ti3C2, and g-C3N4. As can be seen from the figures, the 2θ=39° diffraction peak on the (104) plane of Ti3AlC2 is not present in the Ti3C2 pattern, indicating that the Al element in Ti3AlC2 has completely detached due to corrosion by hydrofluoric acid. Furthermore, peaks of TiO2 were observed at 2θ = 37.8°, 62.5°, 70.8°, and 76.5°. However, the 25.1° peak intensity of the TiO2 nanotube array was not very obvious. This phenomenon may be due to the partial coating of the titanium mesh with a mixture of g-C3N4 and Ti3C2, which also indicates that the TiO2 nanotubes in this invention were successfully modified by g-C3N4 and Ti3C2 materials. The XRD curve here should refer to TCN3. Compared with the prepared pure titanium dioxide nanoarrays (TNTAs), TCN3 shows obvious characteristic peaks of TNTAs at 2θ = 37.8°, 62.5°, 70.8°, and 76.5°. However, the characteristic peak of TNTAs at 25.1° is not shown in TCN3, which is due to the coating effect of g-C3N4 and Ti3C2.

[0077] Figure 5 The images show the FT-IR spectra of the ternary nanocomposites (TCN1, TCN2, TCN3) prepared in Examples 1, 2, and 3 of this invention, the comparative experiment g-C3N4 / TiO2 nanotube array (TCN0), and g-C3N4. As can be seen from the images, in the 3000-3500 cm⁻¹ range... -1 The characteristic absorption band at 1632.5 cm⁻¹ -1 The peak at 813 cm⁻¹ indicates the presence of hydroxyl groups and adsorbed H₂O in the material. -1 The peak at 1200-1640 cm⁻¹ is generated by the vibrational stretching of the triazine unit skeleton of g-C₃N₄. -1The characteristic absorption bands are attributed to the typical stretching mode of the CN heterocyclic structure. The absorption bands in the 470–550 cm⁻¹ region are attributed to the vibrational modes of the Ti-Ti bonds. FT-IR spectra of the prepared materials TCN1, TCN2, TCN3, TCN0, and g-C3N4 in the 3000–3500 cm⁻¹ region are also shown. -1 It exhibits certain characteristic absorption bands, and at 1632.5 cm⁻¹... -1 Characteristic peaks of varying intensities appear in all of them, indicating that the prepared material may contain hydroxyl groups or adsorbed water molecules.

[0078] Figure 6 The images show the UV-Vis spectra of the ternary nanocomposites (TCN1, TCN2, TCN3) prepared in Examples 1, 2, and 3 of this invention, the comparative experiment g-C3N4 / TiO2 nanotube array (TCN0), TNTAs, and g-C3N4. As can be seen from the figures, under visible light irradiation, the maximum absorption wavelength of unloaded g-C3N4 is approximately 460 nm, while that of TiO2 is approximately 380 nm. All composite materials exhibit a wide light absorption range between 470-530 nm, and the peaks are red-shifted relative to TiO2. The band gap energy of the photocatalyst can be obtained through Tauc plotting. The X-axis intercept shows that the Eg values ​​of the original g-C3N4 and the g-C3N4 / Ti3C2 / TiO2 nanotube array composite material TCN1 are 2.7 eV and 2.2 eV, respectively. These results demonstrate that the composite materials possess a narrow band gap, indicating that the photocatalytic performance of the photocatalytic materials prepared in this invention is improved under visible light irradiation.

[0079] Figure 7 The figures show the photodynamic phase (PL) spectra of the ternary nanocomposites (TCN1, TCN2, TCN3) prepared in Examples 1, 2, and 3 of this invention, the comparative experiment g-C3N4 / TiO2 nanotube array (TCN0), and g-C3N4 (excitation wavelength of g-C3N4 was 350 nm). As can be seen from the figures, the PL peak intensities of TCN0 (without Ti3C2), TCN3 (g-C3N4∶Ti3C2=40∶1), TCN2 (g-C3N4∶Ti3C2=20∶1), and TCN1 (g-C3N4∶Ti3C2=10∶1) significantly decrease with increasing Ti3C2 content. This phenomenon indicates that the carrier mobility is significantly reduced after g-C3N4 and Ti3C2 are modified onto the TiO2 nanotube array.

[0080] Application examples

[0081] The application of a ternary nanocomposite material of the present invention in the catalytic degradation of water containing organic pollutants was evaluated by irradiating a solution of RhB (10.0 mg / L) and TC-HCl (10.0 mg / L) under visible light, as follows:

[0082] In the experiment, a ternary nanocomposite material measuring approximately 1.5 × 1.0 cm was fixed in the center of a beaker using a transparent support. 50 mL of RhB solution was then added, and the beaker was placed in the dark and magnetically stirred for 30 minutes to reach adsorption-desorption equilibrium. A 300W xenon lamp with a filter (>420 nm) was used as the light source to ensure only visible light illumination. The distance between the visible light source and the solution surface was 15 cm. During the reaction, a portion of the solution (2 mL) was taken every 10 minutes, and the concentration of RhB was recorded at 554 nm using a UV2550 ultraviolet spectrophotometer. This process was repeated several times to observe the degradation efficiency of RhB by the material. The solution was kept stirred throughout the photodegradation process. The photodegradation process and measurement method of TC-HCl were similar to those of RhB, but the sampling interval was changed to 30 minutes, and the maximum measurement wavelength was changed to 357 nm. Binary g-C3N4 / TiO2 nanotube arrays and TiO2 nanotube arrays (TNTAs) were used as control groups.

[0083] Figure 8 The figures show the degradation effects of the ternary nanocomposites (TCN1, TCN2, TCN3) prepared in Examples 1, 2, and 3 of this invention, the g-C3N4 / TiO2 nanotube array (TCN0), and TNTAs on the organic pollutant RhB. As can be seen from the figures, among all the synthesized photocatalysts, TCN1, with the highest Ti3C2 content, exhibited the highest RhB removal efficiency at 96.04%. Photocatalytic degradation experiments of RhB under visible light were also conducted on TCN0, TCN2, and TCN3, with decomposition efficiencies of 64.86%, 90.46%, and 84.79%, respectively. These conclusions demonstrate that the composite materials possess higher photocatalytic activity than the pure TiO2 nanotube array, and that Ti3C2 plays a crucial role as an electron transport bridge.

[0084] Figure 9The figures show the degradation effects of the ternary nanocomposites (TCN1, TCN2, TCN3) prepared in Examples 1, 2, and 3 of this invention, the comparative experiment of g-C3N4 / TiO2 nanotube array (TCN0), and TNTAs on the organic pollutant tetracycline hydrochloride. As can be seen from the figures, among all the synthesized photocatalysts, TCN1, with the highest Ti3C2 content, showed the highest removal efficiency for TC-HCl, at 85.12%. TCN0, TCN2, and TCN3 were also tested for photocatalytic degradation of TC-HCl under visible light, with treatment efficiencies of 53.11%, 78.33%, and 71.34%, respectively. These conclusions further demonstrate that the ternary nanocomposites prepared in this invention possess excellent photocatalytic performance.

[0085] Example 5

[0086] To evaluate the chemical stability and reusability of the composite photocatalytic material prepared in this invention, five cycles of photocatalytic reaction were conducted. After each round of reaction, the ternary nanocomposite material was washed in ethanol and deionized water for 10 minutes each, and then dried in a vacuum drying oven at 80°C for 30 minutes.

[0087] Figure 10 This image shows the cyclic degradation effect of the ternary nanocomposite material of the present invention on Rhodamine B. The degradation operation was the same as in Example 4, with 5 cycles. Figure 10 As can be seen, after five cycles of degradation, the removal efficiency of RhB remained at 94.62%, with almost no decrease, indicating that the ternary material prepared by this invention has excellent stability and reusability.

[0088]

[0089] In summary, the ternary nanocomposite material of the present invention has the advantages of simple preparation, low cost, strong photocatalytic performance, strong chemical stability, and easy recycling and reuse. When using this composite material to degrade organic pollutants in water, it can efficiently and almost completely remove organic pollutants from the water, and has high application value and good application prospects.

[0090] In addition, the g-C3N4 / Ti3C2 / TiO2 nanotube array in this invention has significant advantages over other similar materials (Table 1). For example, Hao et al. [1] prepared TiO2@g-C3N4 nanotube array by template method, and the efficiency of degrading 10 mg / L Rhodamine B within 180 min was 95.68%, which is 3 times longer than the composite material prepared in this experiment to achieve the same removal efficiency. Zhou et al. [2] prepared g-C3N4 nanosheet / TiO2 nanotube array by impregnation method, and the efficiency of degrading 5 mg / L Rhodamine B within 300 min was only 76%, and the efficiency of degrading tetracycline hydrochloride within 300 min was only 36%, and the photocatalytic performance was relatively poor. Zhang et al. [4] prepared a g-C3N4 quantum dot / TiO2 nanotube array by electrolyte method. The efficiency of removing 3 mg / L of rhodamine B within 180 min was only 60%, which is nearly 10 times lower than the photocatalytic material in this experiment. Tong et al. [5] synthesized a g-C3N4 / TiO2 thin film material by sol-gel method. The material degraded 84% of rhodamine B within 300 min. The degradation time was too long and the application prospects were poor. It can be seen that the g-C3N4 / Ti3C2 / TiO2 nanotube array synthesized in this invention has a better degradation efficiency in the removal of rhodamine B and tetracycline hydrochloride.

[0091]

[0092] [1] Hao J, Zhang S, Ren F, et al. Synthesis of TiO2@g-C3N4 core-shellnanorod arrays with Z-scheme enhanced photocatalytic activity under visiblelight [J]. J Colloid Interface Sci, 2017, 508: 419-425.

[0093] [2] Yan D, Wu X, Pei J, et al. Construction of g-C3N4 / TiO2 / Agcomposites with enhanced visible-light photocatalytic activity and antibacterial properties [J]. Ceramics International, 2019:

[0094] [3] Zhang Q, Quan X, Wang H, et al. Constructing a visible-light-driven photocatalytic membrane by g-C3N4 quantum dots and TiO2 nanotube array for enhanced water treatment [J]. Scientific reports, 2017, 7(1): 3128.

[0095] [4] Tong Z, Yang D, Xiao T, et al. Biomimetic fabrication of g-C3N4 / TiO2 nanosheets with enhanced photocatalytic activity toward organic pollutant degradation [J]. Chemical Engineering Journal, 2015, 260: 117-125.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for preparing a ternary nanocomposite material, comprising S1, preparing a titanium mesh with anatase titanium dioxide nanotubes distributed thereon, characterized in that... It also includes the following steps: S2. Melamine and titanium carbide are mixed and ground. The resulting mixture is then subjected to chemical vapor deposition on a titanium mesh on which anatase titanium dioxide nanotubes are distributed to obtain a ternary nanocomposite material with a three-dimensional network structure.

2. The method for preparing the ternary nanocomposite material according to claim 1, characterized in that, In step S2, the mass ratio of melamine to titanium carbide is 10 to 40:1, preferably 10 to 20:

1.

3. The method for preparing ternary nanocomposite materials according to claim 1, characterized in that, In step S2, the grinding time is 20 min to 30 min.

4. The method for preparing the ternary nanocomposite material according to claim 1, characterized in that, In step S2, the calcination temperature of the chemical vapor deposition is 500℃~550℃, the calcination time is 2h~3h, the heating rate during the calcination process is 3℃ / min~5℃ / min, and the calcination is carried out under nitrogen atmosphere protection.

5. The method for preparing ternary nanocomposite materials according to claim 1, characterized in that, In step S2, before performing the chemical vapor deposition, a quartz boat is prepared. 30% to 50% of the mixture by mass is placed on the bottom surface of the quartz boat. The titanium mesh with anatase titanium dioxide nanotubes distributed in step S2 is placed inside the quartz boat. 50% to 70% of the mixture by mass is placed on the titanium mesh with anatase titanium dioxide nanotubes distributed in it. Then, the resulting quartz boat is wrapped with aluminum foil, small holes are made in the aluminum foil, and then chemical vapor deposition is performed.

6. The method for preparing the ternary nanocomposite material according to any one of claims 1 to 5, characterized in that, In step S1, a titanium mesh is immersed in an electrolyte consisting of sodium fluoride, sodium bisulfate, and water. Using the titanium mesh as the working electrode and Pt as the counter electrode, an anodic oxidation reaction is performed, forming several titanium dioxide nanotubes along both the radial and axial directions on the titanium wire. The titanium dioxide nanotubes grow radially along the titanium wire. After cleaning and drying, the mesh is calcined to transform the crystal form of the titanium dioxide nanotubes into anatase, resulting in a titanium mesh with anatase-type titanium dioxide nanotubes distributed on it.

7. The method for preparing ternary nanocomposite materials according to claim 6, characterized in that, In step S1, the titanium mesh is pretreated before being immersed in the electrolyte: the titanium mesh is immersed in hydrofluoric acid solution for 3 to 5 seconds, then washed with ultrapure water more than 3 times, dried, and the dried titanium mesh is degreased by washing with acetone, ethanol and water for more than 15 minutes respectively. The pretreatment is completed. In the hydrofluoric acid solution, the volume ratio of hydrofluoric acid to water is 1 to 3: 1 to 3.

8. A ternary nanocomposite material, characterized in that, The ternary nanocomposite material uses a titanium mesh as a matrix, on which titanium dioxide nanotubes are distributed. The walls of the titanium dioxide nanotubes are modified with graphitic carbon nitride and titanium carbide. The titanium dioxide nanotubes are anatase titanium dioxide nanotubes.

9. The ternary nanocomposite material according to claim 8, characterized in that, The ternary nanocomposite material has a three-dimensional network structure. The titanium dioxide nanotubes distributed on the titanium network are arranged in a honeycomb pattern. The titanium dioxide nanotubes modified with graphitic carbon nitride and titanium carbide are attached to the inner wall of the titanium dioxide nanotube array in a leaf shape.

10. The application of a ternary nanocomposite material as described in claim 8 or 9, or a ternary nanocomposite material prepared by any one of claims 1 to 7, in the photocatalytic degradation of water containing organic pollutants; preferably, the application includes the following steps: The ternary nanocomposite material was added to water containing organic pollutants, and the organic pollutants were degraded under visible light irradiation.

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