Composite material capable of purifying air and application thereof

Abstract

The invention discloses a composite material capable of purifying air and application thereof, the composite material is zinc oxide-titanium dioxide-graphene nano composite powder, and the composite material is prepared by adopting the following method: (1) dissolving zinc acetate and sodium carbonate in water, then adding graphene powder, keeping stirring for 2-3 hours, filtering to obtain a precipitate, washing and drying the precipitate in sequence to obtain a precursor, and drying the precursor to obtain the zinc oxide-titanium dioxide-graphene nano composite powder; roasting the precursor at the temperature of 500 to 600 DEG C for 1 to 2 hours to obtain zinc oxide-graphene nano composite powder; (2) mixing the zinc oxide-graphene nano composite powder with absolute ethyl alcohol and glacial acetic acid, then adding tetrabutyl titanate for hydrolysis, performing water bath evaporation drying, and then performing drying treatment to obtain zinc oxide-titanium dioxide-graphene nano composite powder; and (3) carrying out ball milling treatment on the zinc oxide-titanium dioxide-graphene nano composite powder. The composite material is environment-friendly, low in cost, excellent in purification effect and capable of effectively purifying indoor and outdoor air for a long time.

Description

[0001] This application is a divisional application of the Chinese patent application "An Environmentally Friendly Ecological Water Filter Plate Capable of Purifying Air and Its Preparation Method" (application number: 2024109745418, application date: July 19, 2024). Technical Field

[0002] This application belongs to the technical field of air purification, and particularly relates to a composite material capable of purifying air and its application. Background Art

[0003] Indoor and outdoor air pollution has become a global problem, causing serious harm to both the ecological environment and human health. Most indoor air pollutants come from indoor decoration materials and furniture, such as formaldehyde, ammonia, VOCs (volatile organic compounds), etc. These air pollutants have seriously threatened human health. Vehicle exhaust emissions are one of the important sources of outdoor air pollutants. The main harmful components of vehicle exhaust are NO x , HC compounds, CO, SO 2 etc. These harmful components endanger the ecological environment and human health.

[0004] Currently, the commonly used indoor and outdoor air purification methods include purification methods based on physical adsorption and purification methods based on photocatalyst media. The purification method based on physical adsorption has drawbacks: physical adsorption is reversible, and when the adsorption is saturated, it will release in situ, which may instead cause greater pollution. Therefore, the adsorption material needs to be replaced regularly. For the purification method based on photocatalyst media, it uses photocatalyst media to degrade harmful components. The common photocatalyst is titanium dioxide, which has a narrow spectral range and absorbs less than 10% of visible light, resulting in limited air purification effect. Summary of the Invention

[0005] The purpose of this application is to provide a composite material capable of purifying air and its application, and this composite material has a more efficient air purification effect.

[0006] This application provides a composite material capable of purifying air, which is zinc oxide - titanium dioxide - graphene nanocomposite powder, and it is prepared by the following method:

[0007] (1) Take zinc acetate and sodium carbonate and dissolve them in water, then add graphene powder, keep stirring for 2 - 3 h, filter to obtain a precipitate, wash and dry the precipitate successively to obtain a precursor, and calcine the precursor at a temperature of 500 - 600 °C for 1 - 2 h to obtain zinc oxide - graphene nanocomposite powder;

[0008] (2) Mix the zinc oxide - graphene nanocomposite powder with absolute ethanol and glacial acetic acid, then add tetrabutyl titanate for hydrolysis, evaporate to dryness in a water bath and then perform a drying treatment to obtain zinc oxide - titanium dioxide - graphene nanocomposite powder;

[0009] (3) Perform ball milling on the zinc oxide - titanium dioxide - graphene nano - composite powder;

[0010] In step (1), the mass ratio of zinc acetate, sodium carbonate, and graphene powder is 22:10 - 15:44;

[0011] In step (2), the mass ratio of the zinc oxide - graphene nano - composite powder and tetrabutyl titanate is 30:6 - 9.

[0012] In some specific embodiments, in step (2), the mass ratio of the zinc oxide - graphene nano - composite powder, glacial acetic acid, and tetrabutyl titanate is 30:2 - 5:6 - 9; and the dosage ratio of tetrabutyl titanate and absolute ethanol is 6 - 9 g:80 - 100 mL.

[0013] The composite material of the present application mainly utilizes photocatalysis to oxidize harmful substances such as toluene and nitrogen oxides in the air, decomposing the harmful gases into carbon dioxide and water, thereby achieving the effect of purifying the air.

[0014] In the composite material, zinc oxide and titanium dioxide play a photocatalytic role. Zinc oxide with a wide bandgap can promote the photogenerated carriers of titanium dioxide with a narrow bandgap, inhibiting the recombination of electron - hole pairs, thereby improving the photocatalytic efficiency. At the same time, since the conduction band energy levels of zinc oxide and titanium dioxide are higher than the Fermi level of graphene, photogenerated electrons are easily transferred through the interface formed by the semiconductor materials (i.e., zinc oxide and titanium dioxide) and graphene, transferring the photogenerated electrons to the target reactants at an extremely high carrier migration rate, thereby improving the efficiency and effect of degrading pollutants.

[0015] The composite material for purifying air provided by the present application is environmentally friendly, low - cost, and has excellent purification effects, and can effectively purify indoor and outdoor air for a long time. Applying this composite material to floor materials, road surface materials, or wall materials can achieve self - purification of indoor and outdoor air. Specific Embodiments

[0016] In order to make the purpose, technical solutions, and beneficial effects of the present application clearer and more understandable, the following further details the present application in conjunction with embodiments.

[0017] A composite material for purifying air provided by the present application is a zinc oxide - titanium dioxide - graphene nano - composite powder, which is prepared by the following method:

[0018] (1) Take zinc acetate and sodium carbonate and dissolve them in water, then add graphene powder and mix, keep stirring for 2 - 3 h. Zinc acetate and sodium carbonate react to obtain a precipitate. Wash and dry the precipitate successively to obtain a precursor. Bake the precursor at a temperature of 500 - 600 °C for 1 - 2 h to obtain the zinc oxide - graphene nano - composite powder;

[0019] In this step, zinc acetate and sodium carbonate react, and the reaction products include zinc hydroxide precipitate and soluble sodium salt. Zinc oxide is decomposed by roasting the zinc hydroxide precipitate. It is easier to decompose nanoscale zinc oxide by roasting at a temperature of 500 - 600°C.

[0020] (2) Mix the zinc oxide-graphene nanocomposite powder with absolute ethanol and glacial acetic acid, then add tetrabutyl titanate and hydrolyze for 0.5 - 1 h. After evaporating the water bath to dryness and drying, zinc oxide-titanium dioxide-graphene nanocomposite powder is obtained.

[0021] (3) Perform ball milling on the zinc oxide-titanium dioxide-graphene nanocomposite powder.

[0022] In this specific embodiment, the mass ratio of zinc acetate, sodium carbonate and graphene powder in step (1) is 22:10 - 15:44; in step (2), the mass ratio of the zinc oxide-graphene nanocomposite powder, glacial acetic acid and tetrabutyl titanate is 30:2 - 5:6 - 9, and the dosage ratio of tetrabutyl titanate and absolute ethanol is 6 - 9 g:80 - 100 mL.

[0023] In this application, zinc oxide and titanium dioxide play a photocatalytic role. Photo-generated electrons are transferred through the interface formed by the semiconductor materials (i.e., zinc oxide and titanium dioxide) and graphene. Too little graphene will cause the semiconductor materials to be difficult to fully contact with graphene, thus affecting the transfer of photo-generated electrons; since graphene itself has basically no photocatalytic effect, too much graphene will affect the photocatalytic effect of zinc oxide and titanium dioxide. Therefore, a specific dosage of graphene should be used to further improve the air purification effect.

[0024] The above composite material can be applied to road surface materials as a purification component, such as an ecological water filter plate. Its preparation method is as follows:

[0025] (1) Take aggregate, polymer, resin-modified cement-based composite binder and composite material by weight, put them into a mixing pot and stir and mix, then add mixing water and continue to stir to obtain a mixture; the dosage of mixing water is in accordance with the conventional dosage. In some specific embodiments, the dosage of mixing water is 3% - 8% of the weight of the raw material mixture.

[0026] (2) Place the mixture in a mold and compact it by static pressure to form a shape.

[0027] (3) After curing, an environmentally friendly ecological water filter plate is obtained.

[0028] The weight parts of the aggregate, cement-based composite binder and composite material can be: 300 - 380 weight parts of aggregate, 50 - 70 weight parts of cement-based composite binder, and 10 - 30 weight parts of composite material.

[0029] Several embodiments and comparative examples of the application of composite materials will be provided below. It should be noted that in the embodiments and comparative examples, the aggregate used is quartz sand with a particle size of 40 to 60 mesh, and the graphene powder used has a particle size of 3 to 9 nm.

[0030] The polymer and resin modified cement-based composite adhesive uses the adhesive in the Chinese patent with the publication number CN113831077B. Specifically, the product of Example 1 in this Chinese patent is used, and the specific preparation method is as follows:

[0031] (1) Preparation of cement-based material:

[0032] Weigh raw materials: 50 parts by weight of PⅠ52.5 type portland cement, 12 parts by weight of strength-enhancing expansion agent, 30 parts by weight of stone powder, 4 parts by weight of iron oxide red pigment, 1 part by weight of dispersant, 1 part by weight of P8850 defoamer, 1 part by weight of wood fiber, and 1 part by weight of setting retarder.

[0033] (2) Preparation of resin base material:

[0034] Weigh raw materials: 50 parts by weight of aspartic polyurea resin, 40 parts by weight of aliphatic isocyanate, and 10 parts by weight of elastomeric polyurea curing agent.

[0035] (3) Preparation of adhesive:

[0036] According to the weight ratio of resin base material∶cement-based material∶nano-pure acrylic emulsion = 3:10:2, first mix the cement-based material and nano-pure acrylic emulsion and stir for 3 min until it becomes a uniform slurry state, then add the mixed resin base material into it and continue to mix and stir for 3 min to obtain the polymer and resin modified cement-based composite adhesive.

[0037] Example 1

[0038] The environmentally friendly ecological water filter plate in this example is integrally pressed; among them, the raw materials include: 350 parts by weight of quartz sand, 60 parts by weight of polymer and resin modified cement-based composite adhesive, and 16 parts by weight of composite material.

[0039] The composite material is zinc oxide-titanium dioxide-graphene nano-composite powder, which is prepared by the following method:

[0040] (1) Take zinc acetate and sodium carbonate and dissolve them in water, add graphene powder, keep stirring for 3 h, filter to obtain a white precipitate, wash the precipitate repeatedly with distilled water until the precipitate is neutral; then successively evaporate to dryness in a water bath and dry in an oven to obtain a precursor, and put the precursor into a muffle furnace and calcine it at 500 °C for 1 h to obtain zinc oxide-graphene nano-composite powder;

[0041] (2) Take zinc oxide-graphene nano-composite powder, anhydrous ethanol and glacial acetic acid and mix them. Then add tetrabutyl titanate for hydrolysis. After that, evaporate to dryness in a water bath and then put it in an oven for drying to obtain zinc oxide-titanium dioxide-graphene nano-composite powder;

[0042] (3) Put the zinc oxide-titanium dioxide-graphene nano-composite powder into a ball mill and ball mill for 1 hour;

[0043] In step (1), the mass ratio of zinc acetate, sodium carbonate and graphene powder is 22:10:44; in step (2), the mass ratio of zinc oxide-graphene nano-composite powder, glacial acetic acid and tetrabutyl titanate is 30:2:6, and the dosage ratio of tetrabutyl titanate and anhydrous ethanol is 6g:80ml.

[0044] Example 2

[0045] The environmental protection ecological water filter plate of this example is integrally pressed; among them, the raw materials include: 360 parts by weight of quartz sand, 65 parts by weight of polymer and resin-modified cement-based composite binder, and 18 parts by weight of composite material.

[0046] The composite material is zinc oxide-titanium dioxide-graphene nano-composite powder, which is prepared by the following method:

[0047] (1) Take zinc acetate and sodium carbonate and dissolve them in water. Add graphene powder and keep stirring for 3h. After filtration, a white precipitate is obtained. Wash the precipitate repeatedly with distilled water until the precipitate is neutral; then evaporate to dryness in a water bath and dry in an oven to obtain a precursor. Put the precursor into a muffle furnace and calcine at 500°C for 1h to obtain zinc oxide-graphene nano-composite powder;

[0048] (2) Take zinc oxide-graphene nano-composite powder, anhydrous ethanol and glacial acetic acid and mix them. Then add tetrabutyl titanate for hydrolysis. After that, evaporate to dryness in a water bath and then put it in an oven for drying to obtain zinc oxide-titanium dioxide-graphene nano-composite powder;

[0049] (3) Put the zinc oxide-titanium dioxide-graphene nano-composite powder into a ball mill and ball mill for 1 hour;

[0050] In step (1), the mass ratio of zinc acetate, sodium carbonate and graphene powder is 22:13:44; in step (2), the mass ratio of zinc oxide-graphene nano-composite powder, glacial acetic acid and tetrabutyl titanate is 30:3:7, and the dosage ratio of tetrabutyl titanate and anhydrous ethanol is 7g:90ml.

[0051] Example 3

[0052] The environmentally friendly ecological water filtration plate of this embodiment is integrally pressed; among them, the raw materials include: 380 parts by weight of quartz sand, 70 parts by weight of a polymer and resin-modified cement-based composite binder, and 24 parts by weight of a composite material.

[0053] The composite material is zinc oxide-titanium dioxide-graphene nanocomposite powder, which is prepared by the following method:

[0054] (1) Dissolve zinc acetate and sodium carbonate in water, add graphene powder, keep stirring for 3 h, filter to obtain a white precipitate, repeatedly wash the precipitate with distilled water until the precipitate is neutral; then sequentially evaporate to dryness in a water bath and dry in an oven to obtain a precursor, and put the precursor into a muffle furnace and calcine at 500 °C for 1 h to obtain zinc oxide-graphene nanocomposite powder;

[0055] (2) Take zinc oxide-graphene nanocomposite powder, anhydrous ethanol and glacial acetic acid and mix them, then add tetrabutyl titanate for hydrolysis, and then evaporate to dryness in a water bath and put it into an oven for drying to obtain zinc oxide-titanium dioxide-graphene nanocomposite powder;

[0056] (3) Put the zinc oxide-titanium dioxide-graphene nanocomposite powder into a ball mill and ball mill for 1 hour;

[0057] In step (1), the mass ratio of zinc acetate, sodium carbonate and graphene powder is 22:15:44; in step (2), the mass ratio of zinc oxide-graphene nanocomposite powder, glacial acetic acid and tetrabutyl titanate is 30:5:9, and the dosage ratio of tetrabutyl titanate and anhydrous ethanol is 9 g:100 ml.

[0058] Comparative Example 1

[0059] The environmentally friendly ecological water filtration plate of this comparative example is integrally pressed; among them, the raw materials include: 350 parts by weight of quartz sand, 60 parts by weight of a polymer and resin-modified cement-based composite binder, and 16 parts by weight of a single-component purifying agent.

[0060] The single-component purifying agent is nano-zinc oxide, which is prepared by the following self-made method:

[0061] Take zinc acetate and sodium carbonate in a weight ratio of 22:10 and dissolve them in water, keep stirring for 3 h, filter to obtain a white precipitate, repeatedly wash the precipitate with distilled water until the precipitate is neutral; then sequentially evaporate to dryness in a water bath and dry in an oven to obtain a precursor, and put the precursor into a muffle furnace and calcine at 500 °C for 1 h to obtain nano-zinc oxide.

[0062] Comparative Example 2

[0063] The environmental protection ecological water filter plate of this comparative example is integrally pressed; among them, the raw materials include: 360 parts by weight of quartz sand, 65 parts by weight of a polymer and resin-modified cement-based composite binder, and 18 parts by weight of a single-component purifying agent.

[0064] The single-component purifying agent is nano-titanium dioxide, which is prepared by the following method:

[0065] Take anhydrous ethanol, glacial acetic acid and tetrabutyl titanate and mix them to hydrolyze tetrabutyl titanate, and then dry it in an oven after evaporating to dryness in a water bath to obtain nano-titanium dioxide; among them, the mass ratio of glacial acetic acid to tetrabutyl titanate is 1:3, and the mass ratio of tetrabutyl titanate to anhydrous ethanol is 3g:90ml.

[0066] Comparative Example 3

[0067] The environmental protection ecological water filter plate of this comparative example is integrally pressed; among them, the raw materials include: 380 parts by weight of quartz sand, 70 parts by weight of a polymer and resin-modified cement-based composite binder, and 24 parts by weight of a composite material.

[0068] The composite material is zinc oxide-titanium dioxide nano-composite powder, which is prepared by the following method:

[0069] (1) Take zinc acetate and sodium carbonate in a weight ratio of 22:10 and dissolve them in water, keep stirring for 3h, filter to obtain a white precipitate, and wash the precipitate repeatedly with distilled water until the precipitate is neutral; then evaporate to dryness in a water bath and dry in an oven to obtain a precursor, and put the precursor into a muffle furnace and calcine it at 500°C for 1h to obtain nano-zinc oxide;

[0070] (2) Take nano-zinc oxide, anhydrous ethanol and glacial acetic acid and mix them, then add tetrabutyl titanate for hydrolysis, and then dry it in an oven after evaporating to dryness in a water bath to obtain zinc oxide-titanium dioxide nano-composite powder; among them, the mass ratio of nano-zinc oxide, glacial acetic acid and tetrabutyl titanate is 10:5:9, and the mass ratio of tetrabutyl titanate to anhydrous ethanol is 9g:100ml;

[0071] (3) Put the zinc oxide-titanium dioxide nano-composite powder into a ball mill and ball mill it for 1 hour.

[0072] Comparative Example 4

[0073] The environmental protection ecological water filter plate of this comparative example is integrally pressed; among them, the raw materials include: 350 parts by weight of quartz sand, 60 parts by weight of a polymer and resin-modified cement-based composite binder, and 16 parts by weight of a composite material.

[0074] The composite material is zinc oxide-graphene nano-composite powder, which is prepared by the following method:

[0075] (1) Dissolve zinc acetate and sodium carbonate in water, add graphene powder, keep stirring for 3 h, filter to obtain a white precipitate, repeatedly wash the precipitate with distilled water until the precipitate is neutral; then successively evaporate to dryness in a water bath and dry in an oven to obtain a precursor. Put the precursor into a muffle furnace and calcine at 500 °C for 1 h to obtain zinc oxide-graphene nanocomposite powder; among them, the mass ratio of zinc acetate, sodium carbonate and graphene powder is 22:10:44;

[0076] (2) Put the zinc oxide-graphene nanocomposite powder into a ball mill and ball mill for 1 hour.

[0077] Comparative Example 5

[0078] The eco-friendly ecological water filter plate of this comparative example is integrally pressed; among them, the raw materials include: 350 parts by weight of quartz sand, 60 parts by weight of a polymer and resin-modified cement-based composite binder, and 16 parts by weight of a composite material.

[0079] The composite material is titanium dioxide-graphene nanocomposite powder, which is prepared by the following method:

[0080] (1) Take graphene powder, absolute ethanol and glacial acetic acid and mix them, then add tetrabutyl titanate for hydrolysis, and then evaporate to dryness in a water bath and put it into an oven for drying to obtain titanium dioxide-graphene nanocomposite powder; among them, the mass ratio of graphene powder, glacial acetic acid and tetrabutyl titanate is 20:2:6, and the mass ratio of tetrabutyl titanate and absolute ethanol is 6 g:80 ml;

[0081] (2) Put the titanium dioxide-graphene nanocomposite powder into a ball mill and ball mill for 1 hour.

[0082] Comparative Example 6

[0083] The eco-friendly ecological water filter plate of this comparative example is integrally pressed; among them, the raw materials include: 350 parts by weight of quartz sand, 60 parts by weight of a polymer and resin-modified cement-based composite binder, 4.728 parts by weight of nano-zinc oxide, 1.816 parts by weight of nano-titanium dioxide, and 9.456 parts by weight of graphene.

[0084] In this comparative example, the nano-zinc oxide is prepared by the method disclosed in Comparative Example 1, and the nano-titanium dioxide is prepared by the method disclosed in Comparative Example 2.

[0085] The eco-friendly ecological water filter plates in the above examples and comparative examples are all prepared by the following method:

[0086] (1) Take quartz sand, polymer, resin-modified cement-based composite binder and purifying agent by weight parts, put them into a mixing pot, use a mortar mixer to stir for 1 minute, continue stirring and slowly pour in the mixing water. After the mixing water is added, stir for another 3 minutes. At this time, the raw materials are evenly mixed and in a fine agglomerated state, obtaining a mixture; among them, the amount of mixing water is 5% of the raw material mixture.

[0087] (2) Put the mixture into a mold and compact it using a static pressure molding machine.

[0088] (3) Place it in a curing room at 30 °C for 7 days, and then send it to outdoor normal temperature curing for 28 days to obtain the ecological water filtration board.

[0089] Perform performance tests on the ecological water filtration boards of the examples and comparative examples according to the following methods:

[0090] 1. Compressive strength: Detect according to Appendix A of JC / T945-2005 "Industry Standard for Permeable Bricks".

[0091] 2. Abrasion resistance: Detect the abrasion pit length according to GB / T12988 "Test Method for Abrasion Resistance of Inorganic Floor Materials".

[0092] 3. Permeability coefficient: Detect according to the detection method in JC / T945-2005 "Industry Standard for Permeable Bricks".

[0093] 4. NOx reduction rate: Place the ecological water filtration boards in sealed glass containers of the same volume. The initial concentration of nitrogen oxides in each glass container is 350 mg / L. After the ecological water filtration boards are placed for 24 hours, use the N-(1-Naphthyl)ethylenediamine dihydrochloride spectrophotometric method to test the concentration of nitrogen oxides in the glass containers, and calculate the NOx reduction rate.

[0094] 5. Place the ecological water filtration boards in sealed glass boxes of the same volume, and simulate an environment with a toluene pollution concentration of 200 μg / L in the glass boxes. Place each glass box under the same light condition. The bottom air pressure equilibrium port of the glass box is connected to a water tank to maintain the air pressure and pollution gas concentration in the glass box during sampling. Turn on the convection fan to keep the gas concentration equal everywhere in the glass box. After introducing the pollution gas to the initial concentration, close the air inlet and start the photodegradation process. Then, sample the air in the glass box through a micro-sampling pump, and use gas chromatography to determine the change in gas content during the degradation process, and calculate the toluene removal rate according to the formula Among them, C 0 represents the initial concentration of toluene at the beginning of degradation, unit: μg / m 3 ; C t represents the equilibrium concentration of the pollution gas at the end of the test, unit: μg / m 3 ; The test time for all examples and comparative examples is 6 h.

[0095] Table 1 Performance test data of the ecological water filtration plates in the examples and comparative examples

[0096]

[0097] It can be seen from the performance test data in Table 1 that the compressive strength, abrasion resistance, and water permeability of the ecological water filtration plates in Examples 1-3 and Comparative Examples 1-6 are comparable. However, the NOx reduction rate and toluene removal rate of the ecological water filtration plates in Examples 1-3 are significantly higher, that is, the air purification effect of the ecological water filtration plates in Examples 1-3 is more excellent. In Comparative Example 1, only a single-component purifying agent of nano-zinc oxide is used in the ecological water filtration plate. In Comparative Example 2, only a single-component purifying agent of nano-titanium dioxide is used in the ecological water filtration plate. In Comparative Example 3, a zinc oxide-titanium dioxide nano-composite material is used in the ecological water filtration plate. Compared with the use of a single-component purifying agent, the air purification effect of the zinc oxide-titanium dioxide nano-composite material is slightly improved. In Comparative Example 4, a zinc oxide-graphene nano-composite material is used in the ecological water filtration plate. In Comparative Example 5, a titanium dioxide-graphene nano-composite material is used in the ecological water filtration plate. Compared with Comparative Examples 1 and 2 that only use a single-component purifying agent, the air purification effect of the composite of graphene with only zinc oxide or titanium dioxide is also slightly improved. However, the air purification effect produced by the composite of zinc oxide, titanium dioxide, and graphene is significantly improved.

[0098] Although the purifying agent in Comparative Example 6 includes zinc oxide, titanium dioxide, and graphene, it is actually a mixture of zinc oxide, titanium dioxide, and graphene and is not composite. The purifying agent in Examples 1-3 is a zinc oxide-titanium dioxide-graphene nano-composite powder prepared by a specific method. Compared with the ecological water filtration plate in Comparative Example 6, the NOx reduction rate of the ecological water filtration plate in Example 1 is increased by about 24%, and the toluene removal rate is increased by about 13%, and the purification effect is significantly improved.

[0099] The applicant believes that the mechanism by which the present application can produce the above technical effects is as follows:

[0100] The band gap of zinc oxide is 3.37 eV, and the band gap of titanium dioxide is 3.0 eV - 3.2 eV. When zinc oxide and titanium dioxide are compounded, the wide-bandgap zinc oxide can promote the photo-generated carriers of the narrow-bandgap titanium dioxide and inhibit the recombination of electron-hole pairs, thereby improving the photocatalytic efficiency. At the same time, it is also compounded with graphene. The conduction band energy levels of zinc oxide and titanium dioxide are higher than the Fermi level of graphene. Photo-generated electrons can easily transfer from the semiconductor to graphene through the interface formed by the semiconductor material (i.e., zinc oxide and titanium dioxide) and graphene. The two-dimensional planar structure of graphene composed of a huge conjugated system can transfer photo-generated electrons to the target reactants at an extremely high carrier migration rate. At the same time, it also extends the mean free path of photo-generated electrons. Photo-generated electrons participate in the formation of highly reactive free radicals (such as hydroxyl radicals and peroxyl radicals), non-selectively oxidize and degrade organic pollutants, and photocatalytically sterilize, thereby improving the efficiency of degrading pollutants.

[0101] Note that the above is only the preferred embodiment of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments. Without departing from the concept of the present application, more other equivalent embodiments can be included, all of which fall within the protection scope of the present application.

Claims

1. A composite material capable of purifying air, characterized in that: The composite material is a zinc oxide-titanium dioxide-graphene nanocomposite powder, which is prepared by the following method: (1) dissolving zinc acetate and sodium carbonate in water, adding graphene powder, stirring for 2 to 3 hours, filtering to obtain a precipitate, washing and drying the precipitate in turn to obtain a precursor, and calcining the precursor at 500 to 600° C. for 1 to 2 hours to obtain a zinc oxide-graphene nanocomposite powder; (2) mixing the zinc oxide-graphene nanocomposite powder with anhydrous ethanol and glacial acetic acid, adding tetrabutyl titanate for hydrolysis, evaporating in a water bath, and drying to obtain the zinc oxide-titanium dioxide-graphene nanocomposite powder; (3) ball milling the zinc oxide-titanium dioxide-graphene nanocomposite powder; In step (1), the mass ratio of zinc acetate, sodium carbonate and graphene powder is 22:10 to 15:44; In step (2), the mass ratio of zinc oxide-graphene nanocomposite powder to tetrabutyl titanate is 30:6-9.

2. The composite material capable of purifying air as claimed in claim 1, characterized in that: In step (2), the mass ratio of zinc oxide-graphene nanocomposite powder, glacial acetic acid and tetrabutyl titanate is 30:2-5:6-9; and the amount ratio of tetrabutyl titanate and anhydrous ethanol is 6-9g:80-100mL.

3. Use of the composite material according to any one of claims 1 to 2 as a purification component added to ground materials.

4. Use of the composite material according to any one of claims 1 to 2 as a purification component added to pavement materials.

5. Use of the composite material according to any one of claims 1 to 2 as a purification component added to wall materials.

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