Method for loading copper oxide quantum dots on surface of titanium dioxide

Abstract

The invention belongs to the technical field of photocatalytic materials, and discloses a method for loading copper oxide quantum dots on the surface of titanium dioxide, which comprises the following steps: coating the surface of TiO2 with carbon quantum dots (CQDs) to form a composite material CQDs / TiO2, and placing the prepared material in a dark environment for more than 24 hours, so that the TiO2 of the CQDs / TiO2 is reversibly converted from hydrophilic to hydrophobic, and the CQDs still maintain the hydrophilic property; in a dark environment, CQDs / TiO2 is immersed in a cupric acetate solution, is rapidly taken out and absorbs a surface solution, so that the solution only exists at a CQDs site; and finally, carrying out air calcination at 400 DEG C through a thermal decomposition method, and cooling to obtain a material structure in which the CuO quantum dots are loaded on the surface of TiO2. The method is suitable for functional modification of materials with fine nanostructures, has significant significance in improvement of photocatalyst performance, and provides a new synthesis thought for design of semiconductor quantum dot heterojunction materials.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a method for loading copper oxide quantum dots on the surface of titanium dioxide. Background Technology

[0002] With the rapid development of society, environmental pollution and energy shortage have become increasingly prominent problems. Photocatalysis is a technology that uses solar energy to degrade pollutants, produce hydrogen from water, and utilize CO2 resources. CuO / TiO2 is a common visible light catalyst, in which N-type semiconductor TiO2 is the main catalytic phase. It has always been the "benchmark" of photocatalysts due to its stability, high activity, non-toxicity, and low cost. P-type semi-CuO is used as a co-catalyst, which has the advantages of narrow band gap, strong light absorption (extending to the near-infrared region), low cost, and easy synthesis. CuO composite on TiO2 forms a PN-type heterojunction, which can extend the photoresponse range of the main catalytic phase to the visible light and even the near-infrared region (Ma, J., Tian, ​​Z., Li, L., et al. Loading Nano-CuO on TiO2 Nanomeshes towards Efficient Photodegradation of Methylene Blue[J]. Catalysts 2022, 12 (4): 383.). Studies have shown that the standard PN heterojunction formed by CuO and TiO2 enhances the excitation and separation of photogenerated carriers while suppressing electron-hole recombination. However, the loading of copper oxide on the TiO2 surface causes changes in the depletion layer width of the PN junction, accompanied by varying degrees of band bending in both the copper oxide and TiO2 at the junction ends, leading to changes in catalytic performance. Therefore, precisely controlling the loading of copper oxide is crucial for the design of this type of catalyst. Quantum dots are low-dimensional materials, typically composed of semiconductors or metals, with a three-dimensional scale close to or smaller than the exciton Bohr radius of the material, usually within 10 nm. On the other hand, the effective range of heterojunction materials is usually at the atomic layer level at the interface. Structurally, using quantum dots as a co-catalyst can maximize the co-catalyst efficiency while avoiding adverse effects on the exposure of active sites in the main catalytic phase. Therefore, it is necessary to control the co-catalyst CuO at the quantum dot level as much as possible to facilitate fine structural modification of the main catalytic phase, precise control of the loading, and the release of composite material performance.

[0003] A literature search of existing technologies revealed that Chinese invention patent 202510337134.0 discloses a "Preparation method and application of a photoelectrochemical sensor based on laser-induced titanium dioxide / copper oxide heterostructure". The inventors used titanium carbide / dinitrogenous copper-β-cyclodextrin (MXene / Cu-β-CD) as a precursor and ITO as a substrate, inducing the formation of titanium dioxide / copper oxide heterostructure nanoparticles on the ITO surface under transient high temperature laser conditions. This method is essentially the same as the high-temperature calcination method. Although the process is simple, the equipment cost is high, and the synthesized nanoparticles are at the hundred-nanometer level, resulting in a low specific surface area, which affects performance release. Invention patent 202210907984.6 discloses a "Preparation method of a cuprous oxide / titanium dioxide / graphene oxide ternary nanocomposite". This method uses copper sulfate, titanium sulfate, and sodium acetate solution as raw materials and employs a one-step hydrothermal method to directly synthesize a cuprous oxide / titanium dioxide / graphene oxide composite catalyst. The synthesized Cu2O catalytic particles are relatively fine and uniform, with a particle size controllable between 10-30 nm. However, the hydrothermal method has high requirements for experimental conditions and containers, stringent morphology control, and is not conducive to large-scale production. Invention patent 202410010116.7 discloses "a preparation method and application of a cuprous oxide / titanium dioxide photocatalyst." This method uses a two-step synthesis of sol-gel method combined with calcination, which is lower in cost and more efficient than the above methods. However, its grain size control is relatively large (200-800 nm), resulting in a low specific surface area, which adversely affects performance. The above three methods represent the main methods for synthesizing CuO / TiO2, but there are few reports on the synthesis of supported CuO quantum dots. Therefore, it is necessary to design a method for preparing a copper oxide quantum dot (<10 nm) composite titanium dioxide photocatalyst that can modify the nanoscale fine structure of TiO2 and precisely control the loading of CuO quantum dots, which will be of great significance for improving the performance of CuO / TiO2 materials. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes a method for loading copper oxide quantum dots (CuO) onto a titanium dioxide surface. This method utilizes the photo-induced hydrophilicity of TiO2 under natural conditions and its reversible transformation to hydrophobicity in the dark, as well as the characteristic of carbon quantum dots (CQDs) maintaining their hydrophilicity due to their rich surface hydrophilic groups. CQDs are used as "seeds" in combination with impregnation and thermal decomposition methods to induce in-situ growth of CuO quantum dots on TiO2 nanowires. By controlling the number of CQD "seeds," the loading of CuO quantum dots can be precisely regulated.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for loading copper oxide quantum dots onto a titanium dioxide surface includes the following steps:

[0007] (1) Dissolve CQDs powder, prepare a carbon quantum dot solution of a certain concentration, coat the CQDs solution onto the TiO2 substrate by coating method, place the coated sample into a drying oven at 50-150℃ and dry for 0.5-3 hours to obtain CQDs / TiO2 material;

[0008] (2) Place the CQDs / TiO2 material obtained in step (1) in a dark environment for more than 24 hours to allow TiO2 to reversibly change from hydrophilic to hydrophobic, while the CQDs part remains hydrophilic;

[0009] (3) Keep in the dark environment, place the CQDs / TiO2 obtained by dark treatment in step (2) into an acetate solution with a concentration of 0.05-1 mol / L, then take it out quickly, remove the surface solution at the same time, and then place the sample horizontally to dry;

[0010] (4) The product obtained in step (3) is placed in an air annealing furnace and calcined at a temperature of 350℃-450℃ for 1.5h-3h. After calcination, it is cooled to room temperature in a certain way. This step causes the CQDs to be rapidly oxidized to the point of exhaustion, and finally the CuO quantum dots are deposited on the TiO2 surface composite material (CuO QDs / TiO2).

[0011] Preferably, the CQDs powder in step (1) is dissolved in deionized water or ultrapure water.

[0012] Preferably, the concentration of the carbon quantum dot solution in step (1) is adjusted according to the amount of CuO quantum dots to be loaded. A high concentration of carbon quantum dot solution can form a large amount of CuO quantum dot deposition, while a low concentration of carbon quantum dot solution can form a small amount of CuO quantum dot deposition.

[0013] Preferably, the coating method in step (1) can be one or more of the following: dip coating, spray coating, spin coating.

[0014] Preferably, the acetate in step (3) is copper acetate.

[0015] Preferably, the method for removing surface moisture in step (3) can be one or more of the following: purging, absorption, and centrifugation.

[0016] Preferably, the drying in step (3) can be one or more of the following: forced air drying, vacuum drying, heating drying, and purging drying.

[0017] Preferably, the air annealing furnace in step (4) refers to an industrial furnace or scientific experimental furnace that heat-treats materials under normal atmospheric pressure.

[0018] Preferably, the calcination in step (4) is carried out in an atmospheric air atmosphere.

[0019] Preferably, the cooling method used in step (4) is one or more of the following: furnace cooling, natural air cooling, and accelerated air cooling.

[0020] Compared with the prior art, the present invention has the following technical advantages:

[0021] (1) The key technology of this invention lies in utilizing the photo-induced hydrophilicity and reversible reduction characteristics of TiO2 material. Under the condition that TiO2 is reduced to hydrophobic, CQDs rich in hydrophilic groups are used as "seeds" to induce the in-situ transformation and synthesis of CuO quantum dots. The loading amount of CuO quantum dots can be determined by the number of "seed" CQDs, and the number of CQDs can be adjusted by the solubility of CQDs aqueous solution, thereby achieving precise control of the CuO quantum dot deposition amount.

[0022] (2) The “seed method” involved in this invention is novel and has the advantages of fast preparation speed, mild reaction conditions, low equipment requirements, and non-toxicity compared with existing reported methods such as hydrothermal method, laser method, sol-gel method, physical vapor deposition, and chemical vapor deposition. This novel material design concept will provide a new feasible strategy for the synthesis of semiconductor quantum dots. Attached Figure Description

[0023] Figure 1 This is a (×50000) scanning electron microscope top view of the CuO QDs deposited on the surface of the TiO2 nanowire array in Example 6;

[0024] Figure 2 This is a (×5000) scanning electron microscope cross-sectional morphology image of CuO QDs deposited on the surface of TiO2 nanowire array in Example 6;

[0025] Figure 3 This is a high-resolution transmission electron microscope (TEM) image (×200000) of CuO QDs deposited on TiO2 nanowires in Example 6.

[0026] Figure 4 This is a (×1000000) lattice image of CuO QDs deposited on TiO2 nanowires in Example 6;

[0027] Figure 5 These are the X-ray diffraction patterns of CuOQDs / TiO2 in Examples 1, 2, 3, 4, 5, and 6 of this invention. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the following.

[0029] Comparative Example

[0030] CuO quantum dots are particularly suitable for modifying fine nanostructured TiO2; therefore, this comparative example uses 99.99% pure titanium foil with a thickness of 0.1 mm as the titanium source. Titanium-based TiO2 nanowire array films were prepared according to the method described in Chinese invention patent "A method for preparing a one-dimensional ordered titanium dioxide nanowire array film with high aspect ratio" (patent number: ZL 202210664016.7). The obtained TiO2 nanowire arrays have a diameter distribution range of 9–15 nm, a nanowire length distribution range of 10–15 μm, and an aspect ratio of 900–1200.

[0031] Example 1

[0032] This embodiment uses a TiO2 nanowire array film as a substrate, with CuO quantum dots loaded on the TiO2 nanowires. A titanium-based TiO2 nanowire array film was prepared according to the method described in the comparative example (patent number: ZL 202210664016.7) and cut into 1cm × 1cm pieces. A 0.01 mg / L CQDs solution was prepared and spin-coated onto the surface of the TiO2 nanowire array film. The spin-coating speed was set to 2500 rpm, the coating time to 30 seconds, and the coating temperature to room temperature. The coating process was repeated three times to ensure uniform coating. The coated sample was placed in a vacuum drying oven with the vacuum level controlled below 1 Pa and the temperature at 80°C. After drying for 2 hours, CQDs / TiO2 was obtained. The CQDs / TiO2 was placed in a dry, sealed, dark environment for 48 hours to ensure that the TiO2 reverted from hydrophilic to hydrophobic. At this point, the TiO2 portion of the substrate was hydrophobic, while the CQDs remained hydrophilic. After dark treatment, the CQDs / TiO2 was immersed in a 0.1 mol / L copper acetate solution, then quickly removed and placed on filter paper. The surface solution was blown down using air to ensure full absorption by the filter paper. The sample was then placed horizontally in a vacuum drying oven and dried using the same parameters. All these steps must be performed in the dark. The dried sample was then placed in a muffle furnace and calcined at 400°C for 2 hours in air. The calcined sample was then cooled to room temperature with the furnace. The final product, CuOQDs / TiO2, was obtained.

[0033] X-ray diffraction was performed on the sample to analyze its phase composition. The test results are attached. Figure 5As shown in the figure, no characteristic peaks of CuO were found in the spectrum. This is because the concentration of the "seed" CQDs was low, resulting in a low content of synthesized CuO, which was below the detection limit of XRD. X-ray energy dispersive spectroscopy (EDS) analysis showed that the mass ratio of CuO QDs in CuO QDs / TiO2 was 0.75%.

[0034] Example 2

[0035] This embodiment uses a TiO2 nanowire array film as a substrate, with CuO quantum dots loaded on the TiO2 nanowires. A titanium-based TiO2 nanowire array film was prepared according to the method described in the comparative example (patent number: ZL 202210664016.7) and cut into 1cm × 1cm pieces. A 0.025 mg / L CQDs solution was prepared and spin-coated onto the surface of the TiO2 nanowire array film. The spin-coating speed was set to 2500 rpm, the coating time to 30 seconds, and the coating temperature to room temperature. The coating process was repeated three times to ensure uniform coating. The coated sample was placed in a vacuum drying oven with the vacuum level controlled below 1 Pa and the temperature at 80°C. After drying for 2 hours, CQDs / TiO2 was obtained. The CQDs / TiO2 was placed in a dry, sealed, dark environment for 48 hours to ensure that the TiO2 changed from hydrophilic to hydrophobic. At this point, the TiO2 portion of the substrate is hydrophobic, while the CQDs remain hydrophilic. After dark treatment, the CQDs / TiO2 was immersed in a 0.1 mol / L copper acetate solution, then quickly removed and placed on filter paper. The surface solution was blown down using air to ensure full absorption by the filter paper. The sample was then placed horizontally in a vacuum drying oven and dried using the same parameters. All these steps must be performed in the dark. The dried sample was then placed in a muffle furnace and calcined at 400°C for 2 hours in air. The calcined sample was then cooled to room temperature with the furnace. The final product, CuOQDs / TiO2, was obtained.

[0036] X-ray diffraction was performed on the sample to analyze its phase composition. The test results are attached. Figure 5 As shown in the figure, no characteristic peaks of CuO were found in the spectrum. This is also because the concentration of the "seed" CQDs is low, resulting in a low content of synthesized CuO, which is difficult to detect by XRD. EDS energy dispersive spectroscopy analysis showed that the mass ratio of CuO QDs in CuO QDs / TiO2 is 1.62%.

[0037] Example 3

[0038] This embodiment uses a TiO2 nanowire array film as a substrate, with CuO quantum dots loaded on the TiO2 nanowires. A titanium-based TiO2 nanowire array film was prepared according to the method described in the comparative example (patent number: ZL 202210664016.7) and cut into 1cm × 1cm pieces. A 0.05 mg / L CQDs solution was prepared and spin-coated onto the surface of the TiO2 nanowire array film. The spin-coating speed was set to 2500 rpm, the coating time to 30 seconds, and the coating temperature to room temperature. The coating process was repeated three times to ensure uniform coating. The coated sample was placed in a vacuum drying oven with the vacuum level controlled below 1 Pa and the temperature at 80°C. After drying for 2 hours, CQDs / TiO2 was obtained. The CQDs / TiO2 was placed in a dry, sealed, dark environment for 48 hours to ensure that the TiO2 changed from hydrophilic to hydrophobic. At this point, the TiO2 portion of the substrate is hydrophobic, while the CQDs remain hydrophilic. After dark treatment, the CQDs / TiO2 was immersed in a 0.1 mol / L copper acetate solution, then quickly removed and placed on filter paper. The surface solution was blown down using air to ensure full absorption by the filter paper. The sample was then placed horizontally in a vacuum drying oven and dried using the same parameters. All these steps must be performed in the dark. The dried sample was then placed in a muffle furnace and calcined at 400°C for 2 hours in air. The calcined sample was then cooled to room temperature with the furnace. The final product, CuOQDs / TiO2, was obtained.

[0039] X-ray diffraction was performed on the sample to analyze its phase composition. The test results are attached. Figure 5 As shown in the figure, no characteristic peaks of CuO were found in the spectrum. This is also because the concentration of the "seed" CQDs is low, resulting in a low content of synthesized CuO, which is difficult to detect by XRD. EDS energy dispersive spectroscopy analysis showed that the mass ratio of CuO QDs in CuO QDs / TiO2 was 2.12%.

[0040] Example 4

[0041] This embodiment uses a TiO2 nanowire array film as a substrate, with CuO quantum dots loaded on the TiO2 nanowires. A titanium-based TiO2 nanowire array film was prepared according to the method described in the comparative example (patent number: ZL 202210664016.7) and cut into 1cm × 1cm pieces. A 0.075 mg / L CQDs solution was prepared and spin-coated onto the surface of the TiO2 nanowire array film. The coating speed was set to 2500 rpm, the coating time to 30 seconds, and the coating temperature to room temperature. The coating process was repeated three times to ensure uniform coating. The coated sample was placed in a vacuum drying oven with the vacuum level controlled below 1 Pa and the temperature at 80°C. After drying for 2 hours, CQDs / TiO2 was obtained. The CQDs / TiO2 was placed in a dry, sealed, dark environment for 48 hours to ensure that the TiO2 changed from hydrophilic to hydrophobic. At this point, the TiO2 portion of the substrate is hydrophobic, while the CQDs remain hydrophilic. After dark treatment, the CQDs / TiO2 was immersed in a 0.1 mol / L copper acetate solution, then quickly removed and placed on filter paper. The surface solution was blown down using air to ensure full absorption by the filter paper. The sample was then placed horizontally in a vacuum drying oven and dried using the same parameters. All these steps must be performed in the dark. The dried sample was then placed in a muffle furnace and calcined at 400°C for 2 hours in air. The calcined sample was then cooled to room temperature with the furnace. The final product, CuOQDs / TiO2, was obtained.

[0042] X-ray diffraction was performed on the sample to analyze its phase composition. The test results are attached. Figure 5 As shown in the figure, no characteristic peaks of CuO were found in the spectrum. This is also due to the low concentration of the "seed" CQDs, resulting in a low content of synthesized CuO, which is difficult to detect by XRD. EDS energy dispersive spectroscopy analysis showed that the mass ratio of CuO QDs in CuO QDs / TiO2 was 4.78%.

[0043] Example 5

[0044] This embodiment uses a TiO2 nanowire array film as a substrate, with CuO quantum dots loaded on the TiO2 nanowires. A titanium-based TiO2 nanowire array film was prepared according to the method described in the comparative example (patent number: ZL 202210664016.7) and cut into 1cm × 1cm pieces. A 0.1 mg / L CQDs solution was prepared and spin-coated onto the surface of the TiO2 nanowire array film. The spin-coating speed was set to 2500 rpm, the coating time to 30 seconds, and the coating temperature to room temperature. The coating process was repeated three times to ensure uniform coating. The coated sample was placed in a vacuum drying oven with the vacuum level controlled below 1 Pa and the temperature at 80°C. After drying for 2 hours, CQDs / TiO2 was obtained. The CQDs / TiO2 was placed in a dry, sealed, dark environment for 48 hours to ensure that the TiO2 reverted from hydrophilic to hydrophobic. At this point, the TiO2 portion of the substrate was hydrophobic, while the CQDs remained hydrophilic. After dark treatment, the CQDs / TiO2 was immersed in a 0.1 mol / L copper acetate solution, then quickly removed and placed on filter paper. The surface solution was blown down using air to ensure full absorption by the filter paper. The sample was then placed horizontally in a vacuum drying oven and dried using the same parameters. All these steps must be performed in the dark. The dried sample was then placed in a muffle furnace and calcined at 400°C for 2 hours in air. The calcined sample was then cooled to room temperature with the furnace. The final product, CuOQDs / TiO2, was obtained.

[0045] X-ray diffraction was performed on the sample to analyze its phase composition. The test results are attached. Figure 5 As shown, with increasing "seed" CQDs concentration, the CuO QDs content increases, resulting in a weaker characteristic peak of CuO in the spectrum. EDS analysis revealed that the mass ratio of CuO QDs in CuO QDs / TiO2 was 6.56%.

[0046] Example 6

[0047] This embodiment uses a TiO2 nanowire array film as a substrate, with CuO quantum dots loaded on the TiO2 nanowires. A titanium-based TiO2 nanowire array film was prepared according to the method described in the comparative example (patent number: ZL 202210664016.7) and cut into 1cm × 1cm pieces. A 0.2 mg / L CQDs solution was prepared and spin-coated onto the surface of the TiO2 nanowire array film. The spin-coating speed was set to 2500 rpm, the coating time to 30 seconds, and the coating temperature to room temperature. The coating process was repeated three times to ensure uniform coating. The coated sample was placed in a vacuum drying oven with the vacuum level controlled below 1 Pa and the temperature at 80°C. After drying for 2 hours, CQDs / TiO2 was obtained. The CQDs / TiO2 was placed in a dry, sealed, dark environment for 48 hours to ensure that the TiO2 reverted from hydrophilic to hydrophobic. At this point, the TiO2 portion of the substrate was hydrophobic, while the CQDs remained hydrophilic. After dark treatment, the CQDs / TiO2 was immersed in a 0.1 mol / L copper acetate solution, then quickly removed and placed on filter paper. The surface solution was blown down using air to ensure full absorption by the filter paper. The sample was then placed horizontally in a vacuum drying oven and dried using the same parameters. All these steps must be performed in the dark. The dried sample was then placed in a muffle furnace and calcined at 400°C for 2 hours in air. The calcined sample was then cooled to room temperature with the furnace. The final product, CuOQDs / TiO2, was obtained.

[0048] X-ray diffraction was performed on the sample to analyze its phase composition. The test results are attached. Figure 5 As shown, the content of CuO QDs continued to increase, and the characteristic peaks of CuO in the spectrum were further enhanced compared to Example 5. EDS analysis revealed that the mass ratio of CuO QDs in CuO QDs / TiO2 was 8.49%.

[0049] This invention is particularly suitable for modifying fine nanostructures. (See attached...) Figure 1 Appendix Figure 2 Even with a surface loading of 8.49% for CuO QDs, the CuO QDs / TiO2 array maintained its initial nanowire morphology under scanning electron microscopy, and no observable particles or clusters of CuO QDs formed on the nanowire surface. This indicates that the CuO QDs particles are small in size and exceed the resolution of SEM. (The text then abruptly shifts to a seemingly unrelated topic: "Through attached...") Figure 3 Appendix Figure 4High-resolution transmission electron microscopy (SPEM) images confirmed that the size distribution of CuO QDs within the TiO2 nanowires was between 5-10 nm, reaching the quantum dot level (<10 nm). XRD phase analysis of the comparative examples (Examples 1-6) confirmed that the method described in this invention can successfully synthesize CuO QDs quantum dots in situ on the TiO2 surface, with no doping and both forming composite structures. Table 1 summarizes the elemental percentages of the samples from Examples 1-6 as determined by EDS, and the mass ratio of CuO QDs in CuO QDs / TiO2. The results demonstrate the feasibility of the technical route described in this invention, which involves controlling the concentration of "seed" CQDs to regulate the CuO QDs loading.

[0050]

Claims

1. A method for loading copper oxide quantum dots onto the surface of titanium dioxide, characterized in that, Includes the following steps: (1) Dissolve CQDs powder, prepare a carbon quantum dot aqueous solution of a certain concentration, coat the CQDs solution onto the TiO2 substrate by coating method, place the coated sample into a drying oven at 50-150℃ and dry for 0.5-3 hours to obtain CQDs / TiO2 material; (2) Place the CQDs / TiO2 material obtained in step (1) in a dark environment for more than 24 hours to allow TiO2 to reversibly change from hydrophilic to hydrophobic, while the CQDs part remains hydrophilic; (3) Keep in the dark environment, place the CQDs / TiO2 obtained by dark treatment in step (2) into an immersion solution with a concentration of 0.05-1 mol / L, then take it out quickly, remove the surface solution at the same time, and then place the sample horizontally to dry; (4) The product obtained in step (3) is placed in an air annealing furnace and calcined at a temperature of 350℃-450℃ for 1.5h-3h. After calcination, it is cooled to room temperature in a certain way. This step causes the CQDs to be rapidly oxidized and the final CuO quantum dots are deposited on the TiO2 surface composite material.

2. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, The CQDs powder mentioned in step (1) is dissolved in deionized water or ultrapure water.

3. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, The concentration of the carbon quantum dot solution in step (1) is adjusted according to the amount of CuO quantum dots to be loaded. A high concentration of carbon quantum dot solution can form a large amount of CuO quantum dot deposition, while a low concentration of carbon quantum dot solution can form a small amount of CuO quantum dot deposition.

4. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, In step (1), the coating method is one or more of the following: dip coating, spray coating, spin coating.

5. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, The acetate mentioned in step (3) is copper acetate.

6. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, The method for removing the surface solution in step (3) is one or more of the following: purging, absorption, and centrifugation.

7. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, In step (3), the drying process can be one or more of the following: forced air drying, vacuum drying, heating drying, and purging drying.

8. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, In step (4), the air annealing furnace refers to an industrial furnace or scientific experimental furnace that heats materials under normal atmospheric pressure.

9. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, In step (4), calcination is performed in an atmospheric air atmosphere at normal pressure.

10. The method for loading copper oxide quantum dots onto the surface of titanium dioxide according to claim 1, characterized in that, In step (4), the cooling method used is one or more of the following: furnace cooling, natural air cooling, and accelerated air cooling.

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