Cu monatomic anchoring oxygen-enriched defect TiO2 photocatalyst based on light-regulated selective oxidation of 5-hydroxymethylfurfural as well as preparation method and application of Cu monatomic anchoring oxygen-enriched defect TiO2 photocatalyst

Abstract

The invention provides a Cu monatomic anchoring oxygen-enriched defect TiO2 photocatalyst based on selective oxidation of light-regulated 5-hydroxymethylfurfural as well as a preparation method and application of the Cu monatomic anchoring oxygen-enriched defect TiO2 photocatalyst, and belongs to the technical field of biomass catalytic conversion. The preparation method provided by the invention comprises the following steps: dissolving terephthalic acid and a Ti precursor in a solvent I, and preparing a Ti-based metal organic framework through solvothermal reaction; the Ti-based metal organic framework is soaked in an aqueous solution of copper salt, then centrifugation and drying are conducted, and the Cu-loaded MIL-125 catalytic material is obtained; and calcining the Cu-loaded MIL-125 catalytic material to obtain the photocatalyst. The method has the advantages of mild reaction conditions, controllable product and simple process, the obtained photocatalyst can efficiently utilize light energy to realize controllable oxidation of HMF into DFF or FDCA, and the method has good application prospects and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass catalytic conversion, and in particular to a Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst based on light-regulated selective oxidation of 5-hydroxymethylfurfural, and a preparation method and application thereof. Background Art

[0002] The massive consumption of traditional fossil energy and the increasing difficulty of mining have led to tight energy supply. Based on this, it is of great significance to develop and utilize renewable energy, accelerate the adjustment of energy structure, and reduce the dependence on traditional energy. Biomass energy is widely distributed, rich in variety, and low in cost. As the only renewable resource based on carbon in nature, it is considered to be the fourth largest energy source after coal, oil and natural gas. Converting renewable biomass resources into daily fuels and high-value-added fine chemicals is an effective way to achieve "carbon peak" and "carbon neutrality" and cope with energy shortages. In addition, solar energy is the most abundant, cheap and pollution-free renewable energy. The development and utilization of semiconductor materials to achieve efficient utilization of solar energy is of great significance for sustainable production and solving environmental pollution problems. As an emerging technology, semiconductor photocatalysis technology can effectively convert light energy into chemical energy, realize the synthesis of various energy small molecules, fine chemicals and the decomposition of pollutants, which is in line with the sustainable development strategy.

[0003] 5-Hydroxymethylfurfural (HMF) can be obtained from biomass such as lignocellulose and has been selected as one of the 12 most important biomass platform compounds by the U.S. Department of Energy. The selective oxidation of HMF to DFF, FDCA, 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) and 5-formyl-2-furancarboxylic acid (FFCA) has always attracted much attention. Among them, DFF and FDCA have more important economic value. Traditional chemical oxidation techniques usually lead to over-oxidation and mineralization of HMF, accompanied by complex side reactions. Therefore, it is crucial to develop an environmentally friendly HMF oxidation catalytic system. Photocatalytic aerobic oxidation is a mild, low-energy, controllable and sustainable oxidation method with great potential in the value-added conversion of biomass HMF. Summary of the invention

[0004] Based on the above content, the purpose of the present invention is to provide a Cu single atom anchored oxygen-defective TiO2 photocatalyst based on light-regulated selective oxidation of 5-hydroxymethylfurfural and its preparation method and application.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is a method for preparing a Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst, comprising the following steps:

[0007] Terephthalic acid and Ti precursor were dissolved in solvent I to prepare Ti-based metal-organic framework via solvothermal reaction;

[0008] The Ti-based metal organic framework is immersed in an aqueous solution of a copper salt, and then centrifuged and dried to obtain a Cu-loaded MIL-125 catalytic material;

[0009] The Cu-loaded MIL-125 catalytic material is calcined to obtain the Cu single-atom-anchored oxygen-defect-rich TiO2 photocatalyst.

[0010] The second technical solution of the present invention is a Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst prepared by the above-mentioned preparation method.

[0011] The third technical solution of the present invention is an application of the above-mentioned Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst in the light-driven controllable oxidation of HMF to DFF or FDCA.

[0012] The fourth technical solution of the present invention is a method for light-driven controllable oxidation of HMF to DFF or FDCA, wherein 5-hydroxymethylfurfural and the above-mentioned Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst are subjected to a photocatalytic oxidation reaction at room temperature and oxygen conditions; the spectral range of the photocatalytic oxidation reaction is 320-780nm.

[0013] The present invention discloses the following technical effects:

[0014] The method provided by the present invention can be carried out at room temperature with mild reaction conditions, avoiding high temperature, high pressure and high pH reaction conditions, can achieve controllable generation of reaction products, and has a simple operation process and great application potential.

[0015] The Cu single atom anchored oxygen-defective TiO2 photocatalyst provided by the present invention is rich in oxygen vacancies, effectively narrowing the band gap of TiO2 and enhancing its light response range. In addition, the special structure of the catalyst significantly improves the carrier separation ability and enhances the ability to utilize high-energy photons.

[0016] The Cu single atom anchored oxygen-defective TiO2 photocatalyst provided by the present invention can efficiently utilize light energy to realize the controllable oxidation of HMF to DFF or FDCA, and the conversion rate of HMF does not decrease significantly during repeated use for 5 times, and has good application prospects and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 X-ray diffraction spectra of different samples in Examples 1-3 of the present invention;

[0019] Figure 2 The Raman spectra of different samples in Examples 1-3 of the present invention;

[0020] Figure 3 The near edge spectrum and extended edge spectrum of the K edge of the Cu element in the Cu2 / TiO2 photocatalyst in Example 2 of the present invention;

[0021] Figure 4 is the X-ray photoelectron spectrum of the Cu2 / TiO2 photocatalyst and P25 in Example 2 of the present invention, wherein a is the X-ray photoelectron spectrum of O1s in P25 and the Cu2 / TiO2 photocatalyst in Example 2 of the present invention, b is the X-ray photoelectron spectrum of Ti 2p in P25 and the Cu2 / TiO2 photocatalyst in Example 2 of the present invention, and c is the X-ray photoelectron spectrum of Cu 2p in the Cu2 / TiO2 photocatalyst in Example 2 of the present invention;

[0022] Figure 5 Electron spin resonance spectra of different samples in Examples 1-3 of the present invention;

[0023] Figure 6 The UV-visible diffuse reflectance spectra of different samples in Examples 1-3 of the present invention are shown;

[0024] Figure 7 Cu in Examples 4-9 of the present invention x / TiO2 was used as a catalyst for the photocatalytic oxidation of HMF; where a is the Cu x Experimental results of HMF photooxidation to DFF using TiO2 as catalyst, b is Cu 2 / The reusability of TiO2 in the HMF oxidation to DFF experiment. c is the Cu x / TiO2 as a catalyst for the photooxidation of HMF to FDCA, d is Cu 2 / Results of the reusability of TiO2 in the oxidation of HMF to FDCA. DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0027] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0028] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0029] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0030] In the present invention, room temperature means 15-35°C.

[0031] Single-atom catalysts have isolated active sites and can maximize the utilization of atoms. TiO2 stands out in the field of photocatalysis due to its low toxicity, low cost, and good chemical and physical stability. In the present invention, TiO2 is regulated to form a special structure by loading Cu single atoms to improve its photocatalytic performance, thereby achieving light-driven controllable oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) or 2,5-furandicarboxylic acid (FDCA).

[0032] Specifically, one of the technical solutions of the present invention is a method for preparing a Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst, comprising the following steps:

[0033] Terephthalic acid and Ti precursor were dissolved in solvent I, and a Ti-based metal organic framework (denoted as MIL-125) was prepared by solvothermal reaction;

[0034] The Ti-based metal organic framework is immersed in an aqueous solution of a copper salt, and then centrifuged and dried to obtain a Cu-loaded MIL-125 catalytic material (denoted as Cu-MIL-125);

[0035] The Cu-loaded MIL-125 catalytic material is calcined to obtain the Cu single-atom anchored oxygen-defective TiO2 photocatalyst (denoted as Cu x / TiO2).

[0036] In some embodiments of the present invention, the Ti precursor is tetrabutyl titanate; the molar ratio of terephthalic acid to tetrabutyl titanate is 1:(0.15-0.25), preferably 1:0.20; the temperature of the solvent thermal reaction is 150-200°C, and the reaction time is 20-24h.

[0037] In some embodiments of the present invention, the solvent I is a mixed solvent consisting of N,N-dimethylformamide (DMF) and methanol; the volume ratio of DMF to methanol is preferably 9:1.

[0038] In some embodiments of the present invention, the copper salt is CuCl2·2H2O; the mass volume ratio of water in the aqueous solution of the Ti-based metal organic framework and the copper salt is 1g:100-150mL, preferably 1g:120mL; the mass volume ratio of the copper salt to water in the aqueous solution of the copper salt is 5-20mg:60mL.

[0039] In the present invention, the amount of copper salt used is higher than the above parameters, which will lead to the pores of the catalyst being blocked, the specific surface area of ​​the catalyst being reduced, and the metal agglomerating to form nanoclusters. This will further lead to a decrease in the number of active sites, which is not conducive to the diffusion and adsorption of reactants. The products obtained within the mass volume ratio range of the copper salt to water of the present invention are all photocatalysts with highly dispersed Cu atoms.

[0040] In some embodiments of the present invention, the Ti-based metal organic framework is immersed in an aqueous solution of a copper salt, and further includes a stirring or ultrasonic step to fully bond the Ti-based metal organic framework to the copper ions. The present invention does not specifically limit the parameters of stirring and ultrasonication, and conventional technical means of those skilled in the art can be used, for example: stirring at room temperature for 1-6 hours.

[0041] In some embodiments of the present invention, before calcining the Cu-loaded MIL-125 catalytic material, the step of grinding the Cu-loaded MIL-125 catalytic material is also included.

[0042] In some embodiments of the present invention, the calcination temperature is 400-500° C. and the time is 2-6 hours. The present invention removes the organic ligand by calcination.

[0043] In the present invention, calcination temperature and time lower than the above range will result in organic ligands and N,N-dimethylformamide remaining in the pores of the catalyst without being fully removed; temperature and time higher than the above range will cause phase change of titanium dioxide to form anatase and rutile mixed phase. Cu-loaded MIL-125 is calcined within the parameter range, and the obtained TiO2 is all anatase phase.

[0044] The preparation method provided by the present invention has the following advantages:

[0045] 1. The present invention first prepares a Ti-based metal organic framework by a solvothermal method. The metal organic framework is immersed in an aqueous solution of a copper salt, and then calcined to obtain a TiO2 catalyst loaded with Cu single atoms. It is worth noting that since the ratio of tetrabutyl titanate and terephthalic acid is adjusted during the preparation of the Ti-based metal organic framework, a Ti-based metal organic framework rich in Ti vacancies is successfully obtained, which ensures that Cu is present in the impregnation process. 2+ is firmly adsorbed in the Ti vacancies, so that the Cu x The Cu element in the TiO2 catalyst exists in the form of single atoms, which prevents the agglomeration of Cu atoms during high-temperature treatment.

[0046] 2. The catalyst prepared by the method provided by the present invention has good stability. That is, in the single-atom catalyst prepared by the method, the Cu atom replaces the Ti in the TiO2 lattice. 5c The position of Cu-O-Ti forms a stable coordination bond instead of simple adsorption, which ensures the high stability of the photocatalyst during use. Compared with the catalysts prepared by directly using commercial TiO2 through impregnation, photodeposition and other methods, the catalyst prepared by this method is not only more stable, but also rich in oxygen vacancies and has a high specific surface area, which increases the content of active sites.

[0047] 3. Preparation of Cu by optimizing synthesis conditions x / TiO2 catalyst shows better selectivity in the catalytic reaction of 5-hydroxymethylfurfural. That is, in the photocatalytic oxidation reaction, under visible light conditions, 5-hydroxymethylfurfural is oxidized to 2,5-diformylfuran; under simulated sunlight conditions, it is oxidized to 2,5-furandicarboxylic acid. By simply adjusting the light source, two oxidation products can be obtained instead of a single product, and high selectivity is achieved while ensuring a high conversion rate.

[0048] The second technical solution of the present invention is a Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst prepared by the preparation method described in the above technical solution.

[0049] The third technical solution of the present invention is an application of the above-mentioned Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst in the light-driven controllable oxidation of HMF to DFF or FDCA.

[0050] The fourth technical solution of the present invention is a method for light-driven controllable oxidation of HMF to DFF or FDCA, wherein 5-hydroxymethylfurfural and the above-mentioned Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst are subjected to a photocatalytic oxidation reaction at room temperature and oxygen conditions; the spectral range of the photocatalytic oxidation reaction is 320-780nm.

[0051] In some embodiments of the present invention, when the spectral range is 420-780 nm, 5-hydroxymethylfurfural is selectively oxidized to 2,5-diformylfuran; when the spectral range is 320-780 nm, 5-hydroxymethylfurfural is selectively oxidized to 2,5-furandicarboxylic acid.

[0052] In some embodiments of the present invention, the photocatalytic oxidation reaction time is 1-7 hours.

[0053] The present invention uses Cu x / TiO2 is used as a photocatalyst to effectively utilize high-energy photons to activate oxygen, achieving a HMF conversion rate of 79.9%-95.2% in a visible light system (spectral range of 420-780nm), and a DFF yield of up to 71.4%-90.9%; in a simulated sunlight system (spectral range of 320-780nm), the HMF conversion rate is 90.4%-98.8%, and the FDCA yield is as high as 86.1%-98.2%. It can efficiently and selectively convert HMF into DFF or FDCA, and has good application prospects.

[0054] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0055] Unless otherwise specified, the raw materials and reagents used in the examples can be obtained through commercial channels.

[0056] Example 1

[0057] This preparation example provides a Cu single atom anchored oxygen vacancy-rich TiO2 photocatalyst Cu1 / TiO2, and the preparation steps are as follows:

[0058] (1) 3 g of terephthalic acid (18 mmol) and 1.25 mL of tetrabutyl titanate (3.6 mmol) were added to a round-bottom flask containing a mixed solvent of N,N-dimethylformamide and methanol in a volume ratio of 9:1, and stirred to form a uniform solution, which was then heat-treated at 160°C for 20 h; thereafter, the solution was cooled, centrifuged, washed, and dried in a vacuum oven at 80°C to obtain a white powder, which was designated as MIL-125.

[0059] (2) 500 mg of MIL-125 was dispersed in 60 mL of deionized water, and then 5 mg of CuCl2·2H2O was added and stirred at room temperature for 3 h to allow the material to fully bond with Cu ions. After centrifugation, washing, and drying in a vacuum oven at 80 °C, the Cu-loaded MIL-125 catalytic material was obtained, which was recorded as Cu-MIL-125.

[0060] (3) After Cu-MIL-125 is fully ground, it is calcined at 500°C for 4 hours to fully remove the organic ligands. The obtained material is marked as Cu1 / TiO2.

[0061] Example 2

[0062] This preparation example provides a Cu single atom anchored oxygen vacancy-rich TiO2 photocatalyst Cu2 / TiO2, the preparation method is the same as that of Example 1, the only difference is that the addition amount of CuCl2·2H2O is adjusted to 10 mg. The obtained catalyst is marked as Cu2 / TiO2.

[0063] Example 3

[0064] This preparation example provides a Cu single atom anchored oxygen vacancy-rich TiO2 photocatalyst Cu3 / TiO2, the preparation method is the same as that of Example 1, the only difference is that the addition amount of CuCl2·2H2O is adjusted to 20 mg. The obtained catalyst is marked as Cu3 / TiO2.

[0065] Characterization results:

[0066] The Cu obtained in Preparation Example 1-3 x / TiO2 photocatalyst was characterized by X-ray diffraction and Raman spectroscopy. Figure 1 and 2 It can be seen that the present invention successfully prepared Cu single atom anchored oxygen-defective TiO2 photocatalyst, and each step of the reaction in the preparation process was successful.

[0067] The Cu2 / TiO2 photocatalyst obtained in Preparation Example 2 was characterized by the near-edge spectrum and extended-edge spectrum of the K edge of the Cu element. Figure 3 It can be seen that Cu in the Cu2 / TiO2 photocatalyst prepared by the present invention exists in the form of a single atom, which further proves that each preparation step is successful.

[0068] The Cu2 / TiO2 photocatalyst obtained in Preparation Example 2 was characterized by X-ray photoelectron spectroscopy. Figure 4 It can be seen that the Cu2 / TiO2 photocatalyst prepared by the present invention is rich in oxygen vacancies.

[0069] The Cu obtained in Preparation Example 1-3 x / TiO2 photocatalyst was characterized by electron spin resonance. Figure 5 It can be seen that the Cu prepared by the present invention x / TiO2 photocatalyst is rich in oxygen vacancies.

[0070] The Cu obtained in Preparation Example 1-3 x / TiO2 photocatalyst was characterized by UV-visible diffuse reflectance. Figure 6 It can be seen that after Cu single atom anchoring, the absorption range of TiO2 photocatalyst is increased to the visible light region.

[0071] Example 4

[0072] This embodiment provides a method for photocatalytic oxidation of HMF to DFF, which is carried out in the following steps:

[0073] 10 mL of 10 mmol / L 5-hydroxymethylfurfural in acetonitrile and 25 mg of the photocatalyst Cu1 / TiO2 of Example 1 were added to the reactor, a 300 W xenon lamp was used as the light source, the spectral range was adjusted to 420-780 nm, the reaction temperature was maintained at room temperature and the reaction was carried out for 6 h. After the reaction was completed, the liquid phase product was detected by high performance liquid chromatography (HPLC), and the calculated yield of DFF was 78.9%, the selectivity was 94.7%, and the conversion rate of HMF was 83.3% ( Figure 7 ).

[0074] Example 5

[0075] This embodiment provides a method for photocatalytic oxidation of HMF to DFF, which is the same as that of embodiment 4, except that the photocatalyst Cu1 / TiO2 of embodiment 1 is replaced by the photocatalyst Cu2 / TiO2 of embodiment 2. The liquid phase product was detected by HPLC, and the yield of DFF was calculated to be 90.9%, the selectivity was 95.5%, and the conversion rate of HMF was 95.2% ( Figure 7 ).

[0076] Example 6

[0077] This embodiment provides a method for photocatalytic oxidation of HMF to DFF, which is the same as that of embodiment 4, except that the photocatalyst Cu1 / TiO2 of embodiment 1 is replaced by the photocatalyst Cu3 / TiO2 of embodiment 3. The liquid phase product was detected by HPLC, and the yield of DFF was calculated to be 68.5%, the selectivity was 89.3%, and the conversion rate of HMF was 71.4% ( Figure 7 ).

[0078] Example 7

[0079] This example provides a method for photocatalytic oxidation of HMF to FDCA, which is the same as Example 4, except that the spectral range of the xenon lamp is adjusted to 320-780nm, and the photoreaction is carried out for 7h. The liquid phase product is detected by HPLC, and the yield of FDCA is calculated to be 87.4%, the selectivity is 95.5%, and the conversion rate of HMF is 91.5% ( Figure 7 ).

[0080] Example 8

[0081] This example provides a method for photocatalytic oxidation of HMF to FDCA, which is the same as Example 5, except that the spectral range of the xenon lamp is adjusted to 320-780nm, and the photoreaction is carried out for 7h. The liquid phase product is detected by HPLC, and the yield of FDCA is calculated to be 98.2%, the selectivity is 99.4%, and the conversion rate of HMF is 98.8% ( Figure 7 ).

[0082] Example 9

[0083] This example provides a method for photocatalytic oxidation of HMF to FDCA, which is the same as Example 6, except that the spectral range of the xenon lamp is adjusted to 320-780nm, and the photoreaction is carried out for 7h. The liquid phase product is detected by HPLC, and the yield of FDCA is calculated to be 86.1%, the selectivity is 95.2%, and the conversion rate of HMF is 90.4% ( Figure 7 ).

[0084] In summary, the present invention can achieve efficient photocatalytic selective conversion of HMF into DFF or FDCA, and the two oxidation products obtained have high added value. The reaction conditions of the method are mild, the preparation process of the photocatalyst involved is simple, and the catalyst has good stability, and the catalytic activity does not significantly decrease during repeated use for 5 times. Therefore, the present invention has good application prospects.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst, characterized in that: The following steps are involved: Terephthalic acid and Ti precursor were dissolved in solvent I to prepare Ti-based metal-organic framework via solvothermal reaction; The Ti-based metal organic framework is immersed in an aqueous solution of a copper salt, and then centrifuged and dried to obtain a Cu-loaded MIL-125 catalytic material; The Cu-loaded MIL-125 catalytic material is calcined to obtain the Cu single-atom-anchored oxygen-defect-rich TiO2 photocatalyst.

2. The method for preparing Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst according to claim 1, characterized in that: The Ti precursor is tetrabutyl titanate; the molar ratio of terephthalic acid to tetrabutyl titanate is 1:(0.15-0.25); the temperature of the solvent thermal reaction is 150-200° C., and the reaction time is 20-24 hours.

3. The method for preparing Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst according to claim 1, characterized in that: The copper salt is CuCl2·2H2O; the mass volume ratio of water in the aqueous solution of the Ti-based metal organic framework and the copper salt is 1g:100-150mL; the mass volume ratio of the copper salt to water in the aqueous solution of the copper salt is 5-20mg:60mL.

4. The method for preparing Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst according to claim 1, characterized in that: The calcination temperature is 400-500° C. and the calcination time is 2-6 hours.

5. A Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst according to claim 5 in light-driven controllable oxidation of HMF to DFF or FDCA.

7. A method for light-driven controlled oxidation of HMF to DFF or FDCA, characterized in that: 5-Hydroxymethylfurfural and the Cu single atom anchored oxygen-defect-rich TiO2 photocatalyst described in claim 5 are subjected to a photocatalytic oxidation reaction at room temperature and oxygen conditions; the spectral range of the photocatalytic oxidation reaction is 320-780nm.

8. The method of light-driven controlled oxidation of HMF to DFF or FDCA according to claim 7, characterized in that: When the spectral range is 420-780nm, 5-hydroxymethylfurfural is selectively oxidized to 2,5-diformylfuran; when the spectral range is 320-780nm, 5-hydroxymethylfurfural is selectively oxidized to 2,5-furandicarboxylic acid.

9. The method of light-driven controlled oxidation of HMF to DFF or FDCA according to claim 7, characterized in that: The photocatalytic oxidation reaction time is 1-7h.

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