Polymer modified TiO2-x / Fe2O3-y / graphene nano composite material as well as preparation method and application thereof

Abstract

The invention discloses a polymer modified TiO2-x / Fe2O3-y / graphene nano composite material as well as a preparation method and application of the polymer modified TiO2-x / Fe2O3-y / graphene nano composite material. The preparation method comprises the following steps: modifying TiO2 nano particles and Fe2O3 nano particles by using a polymer, so as to obtain modified TiO2 nano particles and modified Fe2O3 nano particles; mixing the polymer modified TiO2 / Fe2O3 with graphene, and carrying out first calcination treatment to obtain a polymer modified TiO2 / Fe2O3 / graphene nano composite material; and mixing the TiO2-x / Fe2O3-y / graphene nano composite material with a reducing agent, and carrying out second calcining treatment under the inert atmosphere condition to prepare the polymer modified TiO2-x / Fe2O3-y / graphene nano composite material, x is more than 0 and less than 2, and y is more than 0 and less than 3. According to the polymer modified TiO2-x / Fe2O3-y / graphene nano composite material provided by the invention, the time for photocatalytic degradation of organic pollutants is relatively short, and the time cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of photocatalytic materials, and in particular to a polymer-modified TiO 2-x / Fe2O 3-y / Graphene nanocomposites and their preparation methods and applications. Background Art

[0002] TiO2 is currently the most widely studied photocatalytic material. The anatase phase of TiO2 has a band gap of 3.2 eV at room temperature, but it suffers from drawbacks such as a wide band gap, limited UV absorption, and the proneness of generated electron-hole pairs to recombine. Therefore, a series of improvements to TiO2 photocatalysts are needed to achieve an ideal catalyst. A common approach is to combine TiO2 with graphene, a material with a large specific surface area and high conductivity, to broaden the photoresponse range, promote the separation of photogenerated electron-hole pairs, and improve its photocatalytic efficiency. However, most studies have only obtained TiO2 / graphene composites by subjecting the synthesized TiO2 / graphene oxide composites to a specific reduction process (such as the addition of a reducing agent or thermal reduction under high temperature and high pressure conditions). This inevitably increases experimental costs. Furthermore, these methods are time-consuming and cumbersome to prepare, and the performance improvement is limited.

[0003] Introducing high molecular weight polymers during the synthesis process can improve the dispersibility of TiO2 particles in the solution and also improve the catalytic performance. Studies have shown that incorporating polymers into the TiO2 system can inhibit charge carrier recombination and improve catalytic stability. For example, patent CN202011319951.7 invented a sol-gel in situ growth method to prepare TiO2 / reduced graphene oxide (rGO) photocatalytic materials, which are then loaded onto chitosan doped with polyvinyl alcohol (PVA) through electrostatic adsorption and cross-linking. The prepared chitosan-based graphene / TiO2 composite microspheres have both adsorption properties and photocatalytic degradation effects on organic pollutants, but the reaction process is complicated and time-consuming, which is not conducive to commercial applications. In addition, the catalytic degradation of organic matter takes a long time in application and the degradation efficiency is low.

[0004] For example, patent CN110385118A invented a method rich in oxygen defects and Ti 3+ The three-dimensional graphene / black titanium dioxide composite material achieves the dual functions of efficient adsorption of pollutants and visible light response, but its preparation process requires the use of strong acid (hydrofluoric acid) reagents, which has low safety and long reaction time. In addition, the catalytic degradation of organic matter in application takes a long time and the degradation efficiency is low.

[0005] In summary, current TiO2 / graphene photocatalysts face challenges such as complex preparation methods, demanding conditions, and a need for improved photocatalytic performance. Therefore, there is a need to develop a photocatalyst with superior photocatalytic performance that is simple to operate, process-controllable, and easily mass-producible. Summary of the Invention

[0006] The main purpose of the present invention is to provide a polymer modified TiO 2-x / Fe2O 3-y / Graphene nanocomposite materials and their preparation methods and applications are provided to overcome the deficiencies in the prior art.

[0007] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0008] One aspect of the present invention provides a polymer-modified TiO 2-x / Fe2O 3-y A method for preparing a graphene nanocomposite material, comprising:

[0009] Modifying TiO2 nanoparticles with a polymer to obtain modified TiO2 nanoparticles, and modifying Fe2O3 nanoparticles with a polymer to obtain modified Fe2O3 nanoparticles;

[0010] The modified TiO2 nanoparticles, modified Fe2O3 nanoparticles and graphene are mixed and subjected to a first calcination treatment to obtain a polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material;

[0011] The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material is mixed with a reducing agent and subjected to a second calcination treatment under inert atmosphere to obtain a polymer modified TiO2 / Fe2O3 / graphene nanocomposite material. 2-x / Fe2O 3-y / graphene nanocomposite material, wherein 0<x<2, 0<y<3.

[0012] Another aspect of the present invention provides a polymer-modified TiO2- x / Fe2O 3- y / graphene nanocomposite material, comprising a graphene sheet and TiO distributed on the surface of the graphene sheet 2-x Nanoparticles and Fe2O 3-y Nanoparticles, TiO 2-x Nanoparticles and Fe2O 3-y The conjugated polymers generated by the polymer connect the nanoparticles to form a heterogeneous interface.

[0013] Another aspect of the present invention also provides the aforementioned polymer-modified TiO 2-x / Fe2O 3-y / Application of graphene nanocomposites in photocatalytic degradation of organic matter.

[0014] Compared with the prior art, the present invention has at least the following advantages:

[0015] The polymer modified TiO 2-x / Fe2O 3-y / Graphene nanocomposites can be made from industrial TiO2 powder, Fe2O3, polymer, graphene and reducing agent, and can be rapidly synthesized in batches using a simple and green technical route. The reaction conditions are easy to control and suitable for large-scale production. 2-x / Fe2O 3- The y / graphene nanocomposite material has good photocatalytic performance, can catalytically degrade organic pollutants in a short time, can reduce time costs, and has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 The polymer-modified TiO prepared in Example 1 of the present invention 2-x / Fe2O 3-y / Scanning electron microscope image of graphene nanocomposite (magnification 18.0k);

[0018] Figure 2 The polymer-modified TiO prepared in Example 1 of the present invention 2-x / Fe2O 3-y / Scanning electron microscope image of graphene nanocomposite (magnification 50.0k);

[0019] Figure 3 The polymer-modified TiO prepared in Example 1 of the present invention 2-x / Fe2O 3-y Comparison of ultraviolet absorption spectra of the graphene nanocomposite material, the catalyst materials prepared in Comparative Examples 1-4, and TiO2 after irradiation for 20 minutes. DETAILED DESCRIPTION

[0020] The present invention will be more fully understood by reading the following detailed description. However, it should be understood that the detailed description disclosed below is merely exemplary of the present invention, and that the present invention may be embodied in a variety of forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as a basis for the claims and as a representative basis for teaching those skilled in the art to variously employ the present invention in virtually any appropriately detailed embodiment.

[0021] As one aspect of the technical solution of the present invention, it relates to a polymer-modified TiO 2-x / Fe2O 3-y The preparation method of the graphene nanocomposite material comprises:

[0022] Modifying TiO2 nanoparticles with a polymer to obtain modified TiO2 nanoparticles, and modifying Fe2O3 nanoparticles with a polymer to obtain modified Fe2O3 nanoparticles;

[0023] The modified TiO2 nanoparticles, modified Fe2O3 nanoparticles and graphene are mixed and subjected to a first calcination treatment to obtain a polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material;

[0024] The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material is mixed with a reducing agent and subjected to a second calcination treatment to obtain a polymer modified TiO2 / Fe2O3 / graphene nanocomposite material. 2-x / Fe2O 3-y / graphene nanocomposite material, wherein 0<x<2, 0<y<3.

[0025] In the present invention, during the calcination of the polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material with a reducing agent (such as NaBH4), the reducing agent destroys the surface structure of the catalyst crystal, causing oxygen to escape from the crystal lattice and react with reduced hydrogen to generate water, and generating oxygen defects on the crystal surface.

[0026] In the present invention, the polymer plays a role in structural stability and guidance during the synthesis process, and after high-temperature calcination, the polymer will generate a conjugated polymer. 2-x and Fe2O 3-y A neat heterogeneous interface is formed between the TiO2 and the conjugated polymer, thereby eliminating the barrier to electron transfer between the interfaces and accelerating electron transfer. 2-x 、Fe2O 3-y The connector between graphene and nanostructured carbon acts as a bridge for electron transfer.

[0027] It should be noted that the second calcination treatment of the present invention is carried out in an inert atmosphere under reducing conditions, and the conjugated polymer formed by calcination exists on the TiO2-x and Fe2O 3-y and it is easier to generate defect sites in reducing atmosphere, making TiO 2-x 、Fe2O 3-y The interaction between the three is stronger and the electron transfer is faster.

[0028] In some embodiments, the TiO2 nanoparticles include any one or more combinations of TiO2 nanoparticles containing a single rutile crystal form, TiO2 nanoparticles containing a single anatase crystal form, and TiO2 nanoparticles containing both anatase and rutile crystal forms.

[0029] In some embodiments, the TiO2 nanoparticles have a particle size of 20 to 400 nm.

[0030] In some embodiments, the Fe2O3 nanoparticles have a particle size of 20 to 400 nm.

[0031] In some embodiments, the polymer includes but is not limited to any one or a combination of two or more of polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinyl pyrrolidone, and sodium polystyrene sulfonate.

[0032] In some embodiments, the weight average molecular weight of the polymer is 10,000 to 3,000,000.

[0033] In some embodiments, the preparation method specifically comprises:

[0034] uniformly dispersing a mixed system comprising TiO2 nanoparticles, Fe2O3 nanoparticles, a polymer, and water to obtain a first dispersion containing modified TiO2 nanoparticles and modified Fe2O3 nanoparticles;

[0035] The first dispersion liquid is mixed and dispersed evenly with the graphene aqueous dispersion liquid to obtain a second dispersion liquid containing modified TiO2 nanoparticles, modified Fe2O3 nanoparticles and graphene. After filtration and drying, the second dispersion liquid is subjected to the first calcination treatment to obtain a polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material.

[0036] In some preferred embodiments, the content of TiO2 nanoparticles in the mixed system is 0.5 wt% to 5.0 wt%.

[0037] In some preferred embodiments, the mass of the Fe2O3 nanoparticles in the mixed system is 0.5% to 2% of the mass of the TiO2 nanoparticles.

[0038] In some preferred embodiments, the mass of the polymer in the mixed system is 1% to 20% of the mass of the TiO2 nanoparticles.

[0039] In some preferred embodiments, the mass ratio of the TiO2 nanoparticles to graphene is 100:1 to 2000:1.

[0040] In some preferred embodiments, the mass concentration of the graphene aqueous dispersion is 0.1 wt% to 2.0 wt%.

[0041] In some preferred embodiments, the graphene sheet size is 0.1 to 5 μm and the thickness is ≤10 nm.

[0042] In some preferred embodiments, the dispersion method includes but is not limited to ultrasonic dispersion.

[0043] In some preferred embodiments, the drying temperature is 60-80° C., and the drying time is 2-3 hours.

[0044] In some preferred embodiments, the temperature of the first calcination treatment is 300-500° C., and the time is 1-5 hours.

[0045] Furthermore, the process conditions of the first calcination treatment include: heating to 300-500° C. at a heating rate of 1-3° C. / min and then calcining for 1-5 hours.

[0046] In some embodiments, the mass ratio of the polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material to the reducing agent is 1:0.1-1.5.

[0047] In the present invention, the degree of reduction is controlled by adjusting the mass ratio of the polymer-modified TiO2 / Fe2O3 / graphene nanocomposite to the reducing agent. A suitable mass ratio ensures sufficient contact between the particles, ensuring the reaction occurs without damaging the catalyst structure. Excessive use of the reducing agent can cause excessive surface defects in the catalyst, creating new sites for electron-hole recombination and reducing the catalyst's reactivity. Therefore, the reducing agent dosage must be limited to a certain range.

[0048] In some embodiments, the reducing agent includes but is not limited to any one or a combination of two or more of sodium borohydride, potassium borohydride, lithium aluminum hydride, sodium hydride, and lithium hydride.

[0049] In some embodiments, the second calcination treatment is performed at a temperature of 300-400° C. and for a time of 1-2 hours.

[0050] In some embodiments, the inert atmosphere includes a nitrogen atmosphere or an argon atmosphere.

[0051] In some preferred embodiments, the process conditions of the second calcination treatment include: heating to 300-400° C. at a heating rate of 1-3° C. / min and then calcining for 1-2 hours.

[0052] In some more specific embodiments, the polymer-modified TiO 2-x / Fe2O 3-y The preparation method of the graphene nanocomposite material comprises the following steps:

[0053] (1) Dispersing TiO2 and Fe2O3 nanoparticles in water and uniformly dispersing them by ultrasonication to form a TiO2 / Fe2O3 nanoparticle dispersion; then adding a certain amount of polymer and ultrasonically treating for 0.5 to 2 hours to obtain a polymer-modified TiO2 / Fe2O3 nanoparticle dispersion;

[0054] (2) dispersing graphene powder in water and ultrasonically treating the water for 0.5 to 2 hours to form a graphene dispersion;

[0055] (3) mixing the polymer-modified TiO2 / Fe2O3 nanoparticle dispersion obtained in step (1) and the graphene dispersion obtained in step (2), and ultrasonically treating the mixture for 1 to 3 hours to obtain a polymer-modified TiO2 / Fe2O3 / graphene dispersion; then filtering the mixture, drying the mixture at 60 to 80°C for 2 to 3 hours, and fully grinding the mixture to obtain a polymer-modified TiO2 / Fe2O3 / graphene composite;

[0056] (4) heating the composite particles (polymer-modified TiO2 / Fe2O3 / graphene composite) in step (3) to 300-500°C at a rate of 1-3°C / min in a static air atmosphere and calcining at a constant temperature for 1-5 hours to obtain a polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material;

[0057] (5) The polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material sample was mixed with a reducing agent in a mass ratio of 1:(0.1-1.5) and ground, and then placed in a tube furnace. The sample was reduced by the reducing gas generated by the gasification of the reducing agent. The calcination temperature was 300-400℃, and the sample was kept warm in an inert atmosphere for 1-2 hours. After the sample was cooled to room temperature, it was washed with deionized water to neutrality to remove the residual reducing agent, and then dried in an oven at 60℃ for 2-3 hours to obtain polymer-modified TiO2. 2-x / Fe2O 3- y / graphene nanocomposites.

[0058] In this invention, α-Fe2O3 is abundant in nature, environmentally friendly, and chemically stable. Compared to TiO2, its band gap is only 2.2 eV, allowing it to effectively utilize visible light in the solar spectrum. Therefore, Fe2O3 and TiO2 are mechanically ground and mixed, followed by calcination to form a heterojunction modification. This synergistic effect improves visible light utilization. Furthermore, defect engineering can modulate the local electronic and geometric structure of the catalyst's active sites. The introduced oxygen defects provide capture sites for photogenerated electrons, inhibiting carrier recombination and promoting electron transitions, thereby significantly enhancing photocatalytic performance.

[0059] As another aspect of the technical solution of the present invention, it relates to the polymer-modified TiO prepared by the above-mentioned preparation method. 2-x / Fe2O 3-y The graphene nanocomposite material comprises a graphene sheet and TiO distributed on the surface of the graphene sheet. 2-x Nanoparticles and Fe2O 3-y Nanoparticles, TiO 2-x Nanoparticles and Fe2O 3-y The conjugated polymers generated by the polymer connect the nanoparticles to form a heterogeneous interface.

[0060] As another aspect of the technical solution of the present invention, it relates to the aforementioned polymer-modified TiO 2-x Application of / Fe2O3-y / graphene nanocomposites in photocatalytic degradation of organic matter.

[0061] In some embodiments, the organic matter includes any one or a combination of two or more of methyl orange, rhodamine B, methylene blue, acid orange 7, and Congo red.

[0062] The present invention is further illustrated by way of examples below, but the invention is not limited to the scope of the examples. The reagents and raw materials used in the following examples are commercially available, and the experimental methods where specific conditions are not specified are generally carried out under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0063] Example 1

[0064] A polymer-modified TiO 2-x / Fe2O 3-y A method for preparing a graphene nanocomposite material comprises the following steps:

[0065] 1g TiO2 and 0.005g Fe2O3 powders were dispersed in 200mL water and dispersed evenly by ultrasonication for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyvinyl alcohol (molecular weight M w=105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% (mass fraction) graphene dispersion (graphene flake size was 0.5μm and thickness was 5nm). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material and NaBH4 were mixed and ground in a mass ratio of 1:0.5, and then heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2h to obtain polymer modified TiO 2-x / Fe2O 3-y / graphene nanocomposites.

[0066] like Figure 1 and Figure 2 As shown, Figure 1 and Figure 2 The polymer-modified TiO prepared in Example 1 2-x / Fe2O 3-x Scanning electron microscope images of TiO / graphene nanocomposites at different angles. 2-x and Fe2O 3-y Nanoparticles are distributed on both sides of the graphene sheet. Due to the small size of the graphene used and the TiO 2-x and Fe2O 3-y The nanoparticles are completely distributed on the graphene surface, so it is difficult to observe individual graphene sheets.

[0067] Example 2

[0068] A polymer-modified TiO 2-x / Fe2O 3-y A method for preparing a TiO2 / Fe2O3 / graphene nanocomposite material (compared with Example 1, the mass ratio of polymer-modified TiO2 / Fe2O3 / graphene powder to NaBH4 is different), comprising the following steps:

[0069] 1g TiO2 and 0.005g Fe2O3 powders were dispersed in 200mL water and dispersed evenly by ultrasonication for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyvinyl alcohol (molecular weight Mw =105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% (mass fraction) graphene dispersion (graphene flake size was 0.5μm and thickness was 5nm). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material and NaBH4 were mixed and ground in a mass ratio of 1:0.1, and then heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2h to obtain polymer modified TiO 2-x / Fe2O 3-y / graphene nanocomposites.

[0070] Example 3

[0071] A polymer-modified TiO 2-x / Fe2O 3- A method for preparing a TiO / graphene nanocomposite material (compared with Example 1, the mass ratio of polymer-modified TiO2 / Fe2O3 / graphene powder to NaBH4 is different) comprises the following steps:

[0072] 1g TiO2 and 0.005g Fe2O3 powders were dispersed in 200mL water and dispersed evenly by ultrasonication for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyvinyl alcohol (molecular weight M w=105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% (mass fraction) graphene dispersion (graphene flake size was 0.5μm and thickness was 5nm). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material and NaBH4 were mixed and ground in a mass ratio of 1:1.5, and then heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2h to obtain polymer modified TiO 2-x / Fe2O 3-y / graphene nanocomposites.

[0073] Example 4

[0074] A polymer-modified TiO 2-x / Fe2O 3- The preparation method of the y / graphene nanocomposite material (compared with Example 1, the doping amount of Fe2O3 is different) comprises the following steps:

[0075] 1g TiO2 and 0.02g Fe2O3 powders were dispersed in 200mL water and ultrasonicated for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyvinyl alcohol (molecular weight M w=105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% (mass fraction) graphene dispersion (graphene flake size was 0.5μm and thickness was 5nm). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material and NaBH4 were mixed and ground in a mass ratio of 1:0.5, and then heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2h to obtain polymer modified TiO 2-x / Fe2O 3-y / graphene nanocomposites.

[0076] Example 5

[0077] A polymer-modified TiO 2-x / Fe2O 3-y A method for preparing a graphene nanocomposite material (compared with Example 1, the reducing agent used is different), comprising the following steps:

[0078] 1g TiO2 and 0.005g Fe2O3 powders were dispersed in 200mL water and dispersed evenly by ultrasonication for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyvinyl alcohol (molecular weight M w=105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% (mass fraction) graphene dispersion (graphene flake size was 0.5μm and thickness was 5nm). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material was mixed with KBH4 in a mass ratio of 1:0.5 and ground. The mixture was heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2h to obtain polymer modified TiO2. 2-x / Fe2O 3- y / graphene nanocomposites.

[0079] Example 6

[0080] A polymer-modified TiO 2-x / Fe2O 3-y A method for preparing a graphene nanocomposite material (compared with Example 1, the polymer used is different), comprising the following steps:

[0081] 1g TiO2 and 0.005g Fe2O3 powders were dispersed in 200mL water and ultrasonicated for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyethylene glycol (molecular weight M w=10000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% (mass fraction) graphene dispersion (graphene flake size was 0.5μm and thickness was 5nm). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material was mixed with KBH4 in a mass ratio of 1:0.5 and ground. The mixture was heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2h to obtain polymer modified TiO2. 2-x / Fe2O 3-y / graphene nanocomposites.

[0082] Example 7

[0083] A polymer-modified TiO 2-x / Fe2O 3-y A method for preparing a graphene nanocomposite material comprises the following steps:

[0084] 5g TiO2 and 0.05g Fe2O3 powders were dispersed in 200mL water and dispersed evenly by ultrasonication for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyvinyl alcohol (molecular weight M w=105000) and sonicated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 0.1g of graphene powder was dispersed in 100mL of water and sonicated for 30 minutes to form a 0.1% graphene dispersion (the graphene flakes used were 0.5μm in size and 5nm in thickness). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (the mass ratio of TiO2 powder to graphene was 100:1) and sonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 70°C for 3 hours. After thorough grinding, the mixture was heated to 300°C in a static air atmosphere at a rate of 1°C / min and calcined for 5 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material and NaBH4 were mixed and ground in a mass ratio of 1:0.1, and then heated to 300℃ at a heating rate of 1℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2.5h to obtain polymer modified TiO 2-x / Fe2O 3-y / graphene nanocomposites.

[0085] Example 8

[0086] A polymer-modified TiO 2-x / Fe2O 3- A method for preparing a graphene nanocomposite material comprises the following steps:

[0087] 10g TiO2 and 0.2g Fe2O3 powders were dispersed in 200mL water and ultrasonicated for 30min to form a TiO2 and Fe2O3 dispersion. 2g polyvinyl alcohol (molecular weight M w=105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 2g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 2.0% graphene dispersion (the graphene flakes used were 0.5μm in size and 5nm in thickness). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (the mass ratio of TiO2 powder to graphene was 2000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 80°C for 2.5 hours. After thorough grinding, the mixture was heated to 500°C in a static air atmosphere at a rate of 3°C / min and calcined for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material and NaBH4 were mixed and ground in a mass ratio of 1:1.5, and then heated to 350℃ at a heating rate of 3℃ / min under argon atmosphere and calcined for 1.5h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 3h to obtain polymer modified TiO 2-x / Fe2O 3-y / graphene nanocomposites.

[0088] Comparative Example 1

[0089] A method for preparing a polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material (compared with Example 1, the experimental process does not undergo a NaBH4 solid-phase reduction process), comprising the following steps:

[0090] 1g TiO2 and 0.005g Fe2O3 powders were dispersed in 200mL water and dispersed evenly by ultrasonication for 30min to form a TiO2 and Fe2O3 dispersion. 0.05g polyvinyl alcohol (molecular weight M w =105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 and Fe2O3 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% graphene dispersion (the graphene flakes used were 0.5μm in size and 5nm in thickness). The polyvinyl alcohol-modified TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (the mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / Fe2O3 / graphene nanocomposite.

[0091] Comparative Example 2

[0092] A polymer-modified TiO 2-x A method for preparing a graphene nanocomposite material (compared with Example 1, no Fe2O3 was added during the experiment) comprises the following steps:

[0093] 1g TiO2 powder was dispersed in 200mL water and ultrasonicated for 30min to form a TiO2 dispersion. 0.05g polyvinyl alcohol (molecular weight M w =105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% by mass graphene dispersion (the graphene flakes used were 0.5μm in size and 5nm in thickness). The polyvinyl alcohol-modified TiO2 dispersion and the graphene dispersion were mixed (the mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite powder sample. The polymer modified TiO2 / graphene nanocomposite material and NaBH4 were mixed and ground in a mass ratio of 1:0.5, and then heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined product was washed with deionized water until neutral and dried at 60℃ for 2h to obtain polymer modified TiO2 / graphene nanocomposite material. 2-x / graphene nanocomposites.

[0094] Comparative Example 3

[0095] A method for preparing a polymer-modified TiO2 / graphene nanocomposite material (compared with Example 1, the experimental process does not add Fe2O3 and does not undergo a NaBH4 solid-phase reduction process), comprising the following steps:

[0096] 1g TiO2 powder was dispersed in 200mL water and ultrasonicated for 30min to form a TiO2 dispersion. 0.05g polyvinyl alcohol (molecular weight M w=105000) and ultrasonically treated for 30 minutes to obtain a polyvinyl alcohol-modified TiO2 aqueous dispersion. 1g of graphene powder was dispersed in 100mL of water and ultrasonically treated for 30 minutes to form a 1% by mass graphene dispersion (the graphene flakes used were 0.5μm in size and 5nm in thickness). The polyvinyl alcohol-modified TiO2 dispersion and the graphene dispersion were mixed (the mass ratio of TiO2 powder to graphene was 1000:1) and ultrasonicated for 1 hour to obtain a polyvinyl alcohol-modified TiO2 / graphene dispersion. The mixture was then filtered and dried at 60°C for 2 hours. After thorough grinding, the mixture was heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a polyvinyl alcohol-modified TiO2 / graphene nanocomposite.

[0097] Comparative Example 4

[0098] A TiO 2-x / Fe2O 3-y A method for preparing a graphene nanocomposite material (compared with Example 1, no polymer was added during the experimental process) comprises the following steps:

[0099] 1g of TiO2 and 0.005g of Fe2O3 powder were dispersed in 200mL of water and sonicated for 30 minutes to achieve uniform dispersion, forming a TiO2 and Fe2O3 dispersion. 1g of graphene powder was dispersed in 100mL of water and sonicated for 30 minutes to form a 1% (mass fraction) graphene dispersion (graphene flake size was 0.5μm and thickness was 5nm). The TiO2 and Fe2O3 dispersions were mixed with the graphene dispersion (mass ratio of TiO2 powder to graphene was 1000:1) and sonicated for 1 hour to obtain a TiO2 / Fe2O3 / graphene dispersion. The mixture was then filtered, dried at 60°C for 2 hours, and thoroughly ground. The mixture was then heated to 400°C in a static air atmosphere at a rate of 2°C / min and calcined for 3 hours to obtain a TiO2 / graphene nanocomposite powder sample. TiO2 / Fe2O3 / graphene nanocomposite materials and NaBH4 were mixed and ground in a mass ratio of 1:0.5, and then heated to 400℃ at a heating rate of 2℃ / min under argon atmosphere and calcined for 2h. The calcined products were washed with deionized water until neutral and dried at 60℃ for 2h to obtain TiO 2-x / Fe2O 3-y / graphene nanocomposites.

[0100] Experimental testing

[0101] The polymer modified TiO 2-x / Fe2O 3-yThe photocatalytic degradation of methyl orange using the graphene nanocomposites, Comparative Examples 1-4, and TiO2 was tested. The specific testing method is as follows: The photocatalytic performance test was conducted in a darkroom, using a 100W LED light (365nm wavelength) as the light source. A 10mg / L methyl orange solution was used as the simulated wastewater. 50mL of the methyl orange solution was added to a 100mL beaker, along with 50mg of the prepared photocatalyst (10mg / mL). Ultrasonication was then performed at room temperature in the dark for 3 minutes to establish adsorption-desorption equilibrium. The light source was then turned on and adjusted to a distance of 10cm for illumination experiments. Samples were taken at regular intervals during the test, centrifuged, and the supernatant was collected for ultraviolet absorption spectroscopy within the range of 200-800nm. The photocatalyst's methyl orange removal efficiency (δ%) was calculated using the following formula:

[0102] δ=(A0-A x ) / A0*100%

[0103] Where: δ is the removal rate of methyl orange solution (%); A0 is the absorbance of the initial methyl orange solution at 464 nm; Ax is the absorbance of the methyl orange solution at 464 nm when sampling at time x.

[0104] like Figure 3 As shown, Figure 3 The polymer-modified TiO prepared in Example 1 2-x / Fe2O 3-x / graphene nanocomposite (PVA-TiO 2-x / Fe2O 3- y / G), the catalysts in Comparative Examples 1-4 (PVA-TiO2 / Fe2O3 / G, PVA-TiO 2-x / G、PVA-TiO2 / G、TiO 2-x / Fe2O 3-y / G) and TiO2 after 20 minutes of light exposure. Figure 3 It can be seen that after 20 minutes of illumination, the degradation rate of methyl orange in Example 1 reached 92.01%, showing a good photocatalytic effect, while the polymer-modified TiO 2-x / Fe2O 3-y / graphene, polymer modified TiO 2-x / Graphene, polymer modified TiO2 / Graphene, TiO 2-x / Fe2O 3-yThe degradation rates of methyl orange by the polymer modified TiO2 and graphene were 84.69%, 82.19%, 76.69%, 83.82% and 62.64%, respectively. At the same time, the photocatalytic tests of Examples 2-8 were carried out. The degradation rates of methyl orange after 20 minutes of illumination were 91.54%, 90.47%, 87.95%, 89.25%, 88.79%, 86.97% and 85.78%, respectively, which were all greater than the photocatalytic efficiency of TiO2. These results show that the polymer modified TiO2 provided by the present invention can effectively reduce the degradation rate of methyl orange. 2-x / Fe2O 3-y / Graphene nanocomposite is an excellent photocatalyst.

[0105] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0106] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A polymer-modified TiO 2-x / Fe2O 3-y / A method for preparing a graphene nanocomposite material, characterized in that: include: Modifying TiO2 nanoparticles with a polymer to obtain modified TiO2 nanoparticles, and modifying Fe2O3 nanoparticles with a polymer to obtain modified Fe2O3 nanoparticles; The modified TiO2 nanoparticles, modified Fe2O3 nanoparticles and graphene are mixed and subjected to a first calcination treatment to obtain a polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material; The polymer modified TiO2 / Fe2O3 / graphene nanocomposite material is mixed with a reducing agent and subjected to a second calcination treatment under inert atmosphere to obtain a polymer modified TiO2 / Fe2O3 / graphene nanocomposite material. 2-x / Fe2O 3-v / graphene nanocomposite material, wherein 0 <x<2,0<y<3。 2. The preparation method according to claim 1, characterized in that The TiO2 nanoparticles include any one or more combinations of TiO2 nanoparticles containing a single rutile crystal form, TiO2 nanoparticles containing a single anatase crystal form, and TiO2 nanoparticles containing both anatase and rutile crystal forms; and / or, the particle size of the TiO2 nanoparticles is 20 to 400 nm; and / or, the particle size of the Fe2O3 nanoparticles is 20 to 400 nm; And / or, the polymer includes any one or a combination of two or more of polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinyl pyrrolidone, and sodium polystyrene sulfonate; And / or, the weight average molecular weight of the polymer is 10,000 to 3,000,000.

3. The preparation method according to claim 1, characterized in that Specifically include: uniformly dispersing a mixed system comprising TiO2 nanoparticles, Fe2O3 nanoparticles, a polymer, and water to obtain a first dispersion containing modified TiO2 nanoparticles and modified Fe2O3 nanoparticles; The first dispersion liquid is mixed and dispersed evenly with the graphene aqueous dispersion liquid to obtain a second dispersion liquid containing modified TiO2 nanoparticles, modified Fe2O3 nanoparticles and graphene. After filtration and drying, the second dispersion liquid is subjected to the first calcination treatment to obtain a polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material.

4. The preparation method according to claim 3, characterized in that The content of TiO2 nanoparticles in the mixed system is 0.5wt% to 5.0wt%; and / or, the mass of the Fe2O3 nanoparticles in the mixed system is 0.5% to 2% of the mass of the TiO2 nanoparticles; And / or, the mass of the polymer in the mixed system is 1% to 20% of the mass of the TiO2 nanoparticles.

5. The preparation method according to claim 3, characterized in that The mass ratio of the TiO2 nanoparticles to the graphene is 100:1 to 2000:1; And / or, the mass concentration of the graphene aqueous dispersion is 0.1wt% to 2.0wt%; And / or, the graphene sheet has a size of 0.1 to 5 μm and a thickness of ≤10 nm.

6. The preparation method according to claim 3, characterized in that The dispersion method includes ultrasonic dispersion; And / or, the drying temperature is 60-80° C., and the drying time is 2-3 hours; And / or, the temperature of the first calcination treatment is 300-500°C and the time is 1-5 hours; preferably, the process conditions of the first calcination treatment include: heating to 300-500°C at a heating rate of 1-3°C / min and then calcining for 1-5 hours.

7. The preparation method according to claim 1, characterized in that The mass ratio of the polymer-modified TiO2 / Fe2O3 / graphene nanocomposite material to the reducing agent is 1:0.1-1.5; and / or, the reducing agent comprises any one or a combination of two or more of sodium borohydride, potassium borohydride, lithium aluminum hydride, sodium hydride, and lithium hydride; and / or, the temperature of the second calcination treatment is 300-400° C. and the time is 1-2 hours; And / or, the inert atmosphere includes a nitrogen atmosphere or an argon atmosphere.

8. The preparation method according to claim 7, characterized in that The process conditions of the second calcination treatment include: heating to 300-400° C. at a heating rate of 1-3° C. / min and then calcining for 1-2 hours.

9. The polymer-modified TiO2 prepared by the preparation method according to any one of claims 1 to 8. x / Fe2O 3-y / graphene nanocomposite material, comprising a graphene sheet and TiO distributed on the surface of the graphene sheet 2-x Nanoparticles and Fe2O 3-y Nanoparticles, TiO 2-x Nanoparticles and Fe2O 3-y The conjugated polymers generated by the polymer connect the nanoparticles to form a heterogeneous interface.

10. The polymer-modified TiO as claimed in claim 9 2-x / Fe2O 3-y / Application of graphene nanocomposites in photocatalytic degradation of organic matter; Preferably, the organic matter includes any one or a combination of two or more of methyl orange, rhodamine B, methylene blue, acid orange 7, and Congo red.

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