Copper-doped titanium dioxide heterojunction photocatalyst as well as preparation method and application thereof
By using copper-doped titanium dioxide heterojunction photocatalysts to support non-noble metal oxides and form heterojunctions, the problem of photogenerated electron-hole recombination in TiO2 was solved, improving photocatalytic activity and photoelectric performance. This enabled efficient photocatalytic hydrogen production and plastic degradation while reducing preparation costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-04-03
AI Technical Summary
Existing TiO2 photocatalysts suffer from severe recombination of photogenerated electrons and holes, leading to reduced photocatalytic hydrogen production and plastic degradation activity. Furthermore, noble metal-based co-catalysts are expensive, scarce, and have poor stability, limiting their large-scale application.
A copper-doped titanium dioxide heterojunction photocatalyst is used. By loading non-noble metal oxides such as Cu and MnOx, a heterojunction is formed to enhance photocatalytic activity and photoelectric performance. The porous structure of the Cu-TiO2 substrate and the interfacial synergy of the metal oxides promote the separation and transfer of photogenerated carriers.
The copper-doped titanium dioxide heterojunction photocatalyst achieved highly efficient photocatalytic hydrogen production and plastic degradation. The light absorption capacity of the photocatalyst in the ultraviolet and visible light regions was improved, the separation efficiency of photogenerated carriers was increased, the hydrogen production rate reached 101.3 mmol·g-1·h-1, and it still maintained excellent performance after five cycles.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials, and particularly relates to a copper-doped titanium dioxide heterojunction photocatalyst, its preparation method, and its application. Background Technology
[0002] With the continuous development of the global economy, energy crises and environmental problems are intensifying, making the development of sustainable new energy sources and the reduction of pollution a current research hotspot. The process of converting solar energy into storable chemical energy has received widespread attention. In this process, photocatalysts play a crucial role. Semiconductor photocatalysts play a vital role in the photocatalytic hydrogen production and degradation of plastics. Titanium dioxide (TiO2) has attracted widespread attention due to its advantages of low cost, environmental friendliness, and chemical stability.
[0003] Currently, TiO2 suffers from severe photogenerated electron-hole recombination problems, significantly reducing its photocatalytic hydrogen production and plastic degradation activity. To address this issue, a series of methods are needed to modify the catalyst, such as supporting co-catalysts and constructing heterojunctions. Although noble metal-based co-catalysts (such as platinum / carbon (Pt / C) and ruthenium oxide (RuO2)) exhibit good catalytic activity, their high cost, scarcity, and poor stability limit their large-scale application. Summary of the Invention
[0004] To overcome the shortcomings of the prior art, this invention provides a copper-doped titanium dioxide heterojunction photocatalyst, its preparation method, and its application. This invention maintains excellent photocatalytic activity and photoelectric performance even after loading with metal oxides. When applied as a photocatalyst for photocatalytic hydrogen production, it exhibits good hydrogen production activity and cycling performance. The use of non-precious metals Cu and manganese oxide as co-catalysts reduces preparation costs and enhances its applicability.
[0005] To achieve one of the above objectives, the present invention adopts the following technical solution: A method for preparing a copper-doped titanium dioxide heterojunction photocatalyst, the specific steps of which are as follows: S1. Prepare a MIL-125 precursor solution, and then perform oil bath, washing and vacuum drying in sequence to obtain MIL-125 particles. S2. Disperse MIL-125 particles in deionized water to obtain MIL-125 dispersion. Then add copper chloride to the MIL-125 dispersion and stir to synthesize the coated precursor. The obtained material is then subjected to centrifugation, water washing, vacuum drying and annealing to obtain Cu-TiO2. S3. Disperse Cu-TiO2 and metal M salt in a methanol-water solution, then evacuate to completely remove dissolved oxygen, ensuring the reactor is in an anaerobic state. Subsequently, stir, centrifuge, wash, and vacuum dry to obtain MO. x / Cu-TiO2, where M is one of Mn, Cr, or Ni.
[0006] Preferably, in step S1, the preparation method of the MIL-125 precursor solution is as follows: 3 g of terephthalic acid is added to 54 mL of N,N-dimethylformamide (DMF) and stirred for 10 minutes, then 6 mL of methanol is added, and after stirring for another 5 minutes, 1.2 mL of tetrabutyl titanate (Ti(OC4H9)4) is added (in order to generate Ti vacancies).
[0007] Preferably, in step S2, the amount of MIL-125 granules is 0.5g, the amount of deionized water is 40mL, the mass percentage of copper chloride is 0.5-1.5wt%, the stirring time is 3h, and the annealing conditions are annealing in air at 450℃ for 4 hours.
[0008] Preferably, in step S3, the amount of Cu-TiO2 used is 0.2g, the mass percentage of metal M salt is 0.05-1wt%, and the methanol aqueous solution contains 17.6mL H2O and 2.4mL methanol; the stirring conditions are under 300W xenon lamp irradiation for 3 h, and Cu-TiO2 will be reduced under light irradiation, which helps MnO to adhere and disperse evenly; wash twice with deionized water.
[0009] Preferably, in step S1, the oil bath conditions are as follows: the MIL-125 precursor solution is transferred into a 100 mL single-necked flask and refluxed at 130°C for 20 h.
[0010] Preferably, in step S1, the washing conditions are as follows: after cooling the solution from the oil bath to room temperature, centrifuge to separate the precipitate, and then wash with N,N-dimethylformamide (DMF) and methanol in sequence.
[0011] Preferably, in step S1, the vacuum drying conditions are 60°C for 12 hours to remove the free solvent adhering to the precipitate.
[0012] Preferably, the metal M salt is one of MnCl4, K2CrO4, and Ni(NO3)2.
[0013] To achieve the second objective mentioned above, this invention provides a method for preparing a copper-doped titanium dioxide heterojunction photocatalyst, wherein the photocatalyst is MO. x / Cu-TiO2, where M is one of Mn, Cr, or Ni.
[0014] To achieve the third objective mentioned above, the present invention provides an application of a copper-doped titanium dioxide heterojunction photocatalyst, which is used in photocatalytic hydrogen production and degradation of plastics.
[0015] The advantages of this invention are: (1) The present invention utilizes a simple impregnation method to successfully deposit different metal oxides on a Cu-TiO2 substrate. As the deposited metal oxides effectively contact the catalyst substrate to form a heterojunction, the photocatalytic activity and photoelectric performance of the catalyst are effectively improved. Furthermore, due to the loose and porous structure of the Cu-TiO2 substrate, the specific surface area is large, which promotes the uniform dispersion of metal oxides and strengthens the synergistic effect of the interface between the two, forming highly efficient catalytic active sites.
[0016] (2) The metal oxide of the catalyst in this invention is tightly coupled with the catalyst substrate, which simultaneously improves the dual-function characteristics. On the one hand, the Cu single atoms in the Cu-TiO2 catalyst substrate act as reactive sites and rapidly transfer photogenerated carriers during the catalytic process. On the other hand, the metal oxide forms a heterojunction with the catalyst, and the loaded metal oxide co-catalyst effectively improves the light absorption performance of the catalyst. The absorption in the ultraviolet and visible light regions is significantly improved compared with the original catalyst. Furthermore, the formation of a heterojunction between the metal oxide and the catalyst further effectively improves the separation efficiency of photogenerated carriers and prevents electron-hole recombination. MnO2 is used as a photocatalytic catalyst for hydrogen production from ethylene glycol aqueous solution. x The Cu-TiO2 photocatalyst achieved a peak hydrogen production rate of 101.3 mmol·g⁻¹. -1 ·h -1， Furthermore, it still exhibits excellent hydrogen production performance after five cycles. Attached Figure Description
[0017] Figure 1 MnO in Embodiment 1 of the present invention x Microscopic morphology images of Cu-TiO2, where a is a scanning electron microscope (SEM) image and b is a high-power transmission electron microscope (HRTEM) image.
[0018] Figure 2 MnO prepared in Example 1 of this invention x XRD patterns of Cu-TiO2, Cu-TiO2 prepared in Comparative Example 1, and TiO2 prepared in Comparative Example 3.
[0019] Figure 3 MnO prepared in Example 1 of this invention x Comparison of photocatalytic activities of Cu-TiO2, Cu-TiO2 prepared in Comparative Example 1, and TiO2 prepared in Comparative Example 3.
[0020] Figure 4 MnO prepared in Example 1 of this inventionx Comparison of photoelectric properties of Cu-TiO2, Cu-TiO2 prepared in Comparative Example 1, and TiO2 prepared in Comparative Example 3.
[0021] Figure 5 MnO prepared in Example 1 of this invention x / Cu-TiO2 cyclic catalytic performance. Detailed Implementation
[0022] Example 1
[0023] This embodiment provides a MnO x The preparation method of Cu-TiO2 heterojunction photocatalyst specifically includes the following steps: S1. Add 3g of terephthalic acid to 54 mL of N,N-dimethylformamide (DMF) and stir for 10 minutes. Then add 6 mL of methanol and stir for another 5 minutes. Finally, add 1.2 mL of tetrabutyl titanate (Ti(OC4H9)4) to prepare the precursor solution of MIL-125.
[0024] S2. The precursor solution of MIL-125 was transferred into a 100 mL single-necked flask tube, refluxed at 130°C for 20 h, then removed, cooled to room temperature, centrifuged to separate the precipitate, washed with DMF and methanol in sequence, and then dried under vacuum at 60°C for 12 h to obtain MIL-125 particles.
[0025] S2. Weigh 0.5g of MIL-125 particles and disperse them in 40 mL of deionized water to obtain a MIL-125 dispersion. Then, add 1wt% CuCl2 to the MIL-125 dispersion and stir for 3 hours to synthesize the coated precursor. After centrifugation and washing with water, the obtained material is dried under vacuum and finally annealed in air at 450°C for 4 hours to obtain Cu-TiO2.
[0026] S3. Disperse 0.2 g Cu-TiO2 and 0.1 wt% manganese chloride (MnCl4) in a methanol-water solution containing 2.4 mL methanol and 17.6 mL ultrapure water. Then, evacuate the solution and stir for 3 h under 300 W xenon lamp irradiation. Centrifuge the sample, wash twice with deionized water, and then vacuum dry to obtain MnO2. x / Cu-TiO2.
[0027] Comparative Example 1
[0028] This comparative example provides a Cu-TiO2 photocatalyst. The specific steps are the same as steps S1 and S2 in Example 1, except that step S3 is omitted. The Cu-TiO2 catalyst is finally obtained.
[0029] Comparative Example 2
[0030] This comparative example provides a TiO2 photocatalyst. The specific steps are the same as in Example 1, except that CuCl2 is not added in step S2, and the TiO2 catalyst is finally obtained.
[0031] MnO prepared in Example 1 x Morphological characterization of Cu-TiO2 was performed, such as... Figure 1 As shown, from Figure 1 It can be seen that Cu-TiO2 loaded with MnO x It can then maintain its original disc-shaped structure, with a size range of 200-300 nm. Figure 1 b shows the TiO2 crystal plane (111) and MnO. x The lattice spacing characteristics of the (002) crystal plane support the MnO x The loads are placed on a TiO2 matrix and are in close contact with each other.
[0032] from Figure 2 As can be seen from the powder X-ray diffraction (PXRD) spectra used to characterize the phase structure, and the data analyzed by Jade6, the XRD peak intensity did not change significantly after Cu loading, indicating that the photodeposited MnO... x The intensity of the later peak decreased to some extent compared to TiO2, indicating that the photodeposited MnO x The loading resulted in a significant decrease in the crystallinity of the TiO2-based catalyst, leading to the deposition of MnO. x It did not change the original crystal form of Cu-TiO2.
[0033] Figure 3 MnO prepared in Example 1 x Photocatalytic hydrogen production performance spectra of Cu-TiO2, Cu-TiO2 prepared in Comparative Example 1, and TiO2 prepared in Comparative Example 2 were obtained. The photocatalytic reaction system was a mixed solution of ethylene glycol (EG) and water. The photocatalytic experiments were conducted on an all-glass automated online trace gas analysis system (Labsolar-6A, Perfect Light Ltd.). When using Labsolar-6A, a xenon lamp (Perfect Light PLSSXE300C) equipped with a filter was used as a simulated solar spectrum light source. The prepared catalyst (5 mg) was uniformly dispersed in 40 mL of H2O / EG solution using a magnetic stirrer (water / ethylene glycol ratio of 1:2). The system underwent multiple vacuum treatments to remove dissolved air, and the amount of hydrogen generated was measured using an online gas chromatograph (GC7900). During the reaction, the temperature was maintained at 15°C through water circulation. Each catalyst group was tested for six hours, and the MnO2 production performance was observed. x The highest hydrogen production activity of Cu-TiO2 reached 101.35 mmol g. -1 h-1 It is 3.36 times that of Cu-TiO2 and 36.72 times that of TiO2.
[0034] Figure 4 MnO prepared in Example 1 x The photoelectric performance spectra of Cu-TiO2, Cu-TiO2 prepared in Comparative Example 1, and TiO2 prepared in Comparative Example 2 are shown. In the figure, a is the UV-Vis absorption image, and b is the photoluminescence (PL) image. As shown in the UV-Vis spectra, all samples exhibit strong optical absorption. MnO x Cu-TiO2 exhibits enhanced overall light absorption compared to TiO2, as shown in the PL spectrum, demonstrating that MnO... x Compared to TiO2 and Cu-TiO2, Cu-TiO2 exhibits slower recombination of photogenerated electrons and holes, which facilitates the separation of photogenerated carriers.
[0035] Figure 5 MnO prepared in Example 1 x The Cu-TiO2 cyclic stability test was conducted under the following conditions: the catalyst (5 mg) was uniformly dispersed in 40 mL of H2O / EG solution using a magnetic stirrer (water / ethylene glycol ratio of 1:2). The system underwent multiple vacuum treatments to remove dissolved air, and the amount of H2 generated was measured using an online gas chromatograph (GC7900). During the reaction, the temperature was maintained at 15°C through water circulation. Each catalyst group was tested for 4 hours.
[0036] In summary, the MnO prepared by this invention... x The Cu-TiO2 catalyst exhibits excellent photocatalytic hydrogen production performance and cycling activity, which is due to the MnO x Nanoparticles loaded on Cu-TiO2 matrix and well bound together further increase reaction sites, enhance absorption in the ultraviolet and visible light regions, promote the transfer of photogenerated carriers, and enhance its photoelectric properties.
[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing a copper-doped titanium dioxide heterojunction photocatalyst, characterized in that, The specific steps are as follows: S1. Prepare a MIL-125 precursor solution, and then perform oil bath, washing and vacuum drying in sequence to obtain MIL-125 particles. S2. Disperse MIL-125 particles in deionized water to obtain MIL-125 dispersion. Then add copper chloride to the MIL-125 dispersion and stir to synthesize the coated precursor. The obtained material is then subjected to centrifugation, water washing, vacuum drying and annealing to obtain Cu-TiO2. S3. Disperse Cu-TiO2 and metal M salt in a methanol-water solution, then apply vacuum, followed by stirring, centrifugation, washing, and vacuum drying to obtain MO. x / Cu-TiO2, where M is one of Mn, Cr, or Ni.
2. The method for preparing a copper-doped titanium dioxide heterojunction photocatalyst according to claim 1, characterized in that, In step S1, the preparation method of the MIL-125 precursor solution is as follows: 3 g of terephthalic acid is added to 54 mL of N,N-dimethylformamide and stirred for 10 minutes, then 6 mL of methanol is added, and after stirring for another 5 minutes, 1.2 mL of tetrabutyl titanate is added.
3. The preparation method and application of a copper-doped titanium dioxide heterojunction photocatalyst according to claim 1, characterized in that: In step S2, the amount of MIL-125 granules used is 0.5g, the amount of deionized water used is 40 mL, the mass percentage of copper chloride is 0.5-1.5wt%, the stirring time is 3h, and the annealing conditions are annealing in air at 450℃ for 4 hours.
4. The preparation method and application of a copper-doped titanium dioxide heterojunction photocatalyst according to claim 1, characterized in that: In step S3, the amount of Cu-TiO2 used is 0.2g, the mass percentage of metal M salt is 0.05-1wt%, and the methanol aqueous solution contains 17.6mL H2O and 2.4mL methanol; the stirring conditions are: stirring for 3 h under 300 W xenon lamp irradiation; and washing twice with deionized water.
5. The preparation method and application of a copper-doped titanium dioxide heterojunction photocatalyst according to claim 1, characterized in that: In step S1, the oil bath conditions are as follows: the MIL-125 precursor solution is transferred into a 100 mL single-necked flask and refluxed at 130°C for 20 hours.
6. The method for preparing a copper-doped titanium dioxide heterojunction photocatalyst according to claim 1, characterized in that: In step S1, the washing conditions are as follows: after cooling the solution from the oil bath to room temperature, centrifuge to separate the precipitate, and then wash with N,N-dimethylformamide and methanol in sequence.
7. The method for preparing a copper-doped titanium dioxide heterojunction photocatalyst according to claim 1, characterized in that: In step S1, the vacuum drying conditions are 60℃ for 12 hours.
8. The method for preparing a copper-doped titanium dioxide heterojunction photocatalyst according to claim 1, characterized in that: The metal M salt is one of MnCl4, K2CrO4, and Ni(NO3)2.
9. A photocatalyst prepared by the method for preparing a copper-doped titanium dioxide heterojunction photocatalyst according to any one of claims 1-8, characterized in that: The photocatalyst is MO. x / Cu-TiO2, where M is one of Mn, Cr, or Ni.
10. The application of the copper-doped titanium dioxide heterojunction photocatalyst according to claim 9, characterized in that: This photocatalyst is used in photocatalytic hydrogen production and plastic degradation.