A Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst based on photo-regulated selective oxidation of 5-hydroxymethylfurfural, its preparation method and application

Abstract

The application provides a Cu monatomic anchoring oxygen-rich defect TiO2 photocatalyst based on light regulation of selective oxidation of 5-hydroxymethylfurfural as well as a preparation method and application thereof, and belongs to the technical field of biomass catalytic conversion. The preparation method provided by the application comprises the following steps: terephthalic acid and a Ti precursor are dissolved in a solvent I, and a Ti-based metal organic framework is prepared through a 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; and the Cu loaded MIL-125 catalytic material is calcined to obtain a photocatalyst. The application has the advantages of mild reaction condition, controllable product, simple process, efficient utilization of light energy to realize controllable oxidation of HMF into DFF or FDCA by the obtained photocatalyst, and good application prospect and economic benefit.

Description

Technical Field

[0001] This invention relates to the field of biomass catalytic conversion technology, and in particular to a Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst based on photo-regulated selective oxidation of 5-hydroxymethylfurfural, its preparation method and application. Background Technology

[0002] The massive consumption of traditional fossil fuels and the increasing difficulty of extraction have led to a tight energy supply. Therefore, developing and utilizing renewable energy sources to accelerate energy structure adjustment and reduce dependence on traditional energy sources is of great significance. Biomass energy, with its wide distribution, abundant varieties, and low cost, and as the only carbon-based renewable resource in nature, is considered the fourth largest energy source after coal, oil, and natural gas. This involves converting renewable biomass resources into fuels and high-value-added fine chemicals needed for daily life. Furthermore, solar energy is the most abundant, inexpensive, and pollution-free renewable energy source. Developing and utilizing semiconductor materials to achieve efficient use of solar energy is of great significance for sustainable production and solving environmental pollution problems. Semiconductor photocatalysis technology, as an emerging technology, can effectively convert light energy into chemical energy, enabling the synthesis of various small energy molecules and fine chemicals, as well as the decomposition of pollutants, which aligns with the sustainable development strategy.

[0003] 5-Hydroxymethylfurfural (HMF) can be obtained from biomass such as lignocellulose and has been selected by the U.S. Department of Energy as one of the 12 most important biomass platform compounds. The selective oxidation of HMF to DFF, FDCA, 5-hydroxymethyl-2-furanocarboxylic acid (HMFCA), and 5-formyl-2-furanocarboxylic acid (FFCA) has been a focus of research. Among these, DFF and FDCA have greater economic value. Traditional chemical oxidation techniques often lead to over-oxidation and mineralization of HMF, accompanied by complex side reactions. Therefore, developing an environmentally friendly HMF oxidation catalytic system is crucial. Photocatalytic aerobic oxidation is a mild, low-energy-consumption, controllable, and sustainable oxidation method with great potential for the value-added conversion of biomass HMF. Summary of the Invention

[0004] Based on the above, the purpose of this invention is to provide a Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst based on photo-controlled selective oxidation of 5-hydroxymethylfurfural, its preparation method, and its application.

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

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

[0007] Ti-based metal-organic frameworks were prepared by dissolving terephthalic acid and Ti precursor in solvent I and reacting them via a solvothermal reaction.

[0008] The Ti-based metal-organic framework was immersed in an aqueous solution of copper salt, followed by centrifugation and drying to obtain Cu-supported MIL-125 catalyst material;

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

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

[0011] The third technical solution of the present invention is the application of the above-mentioned Cu single-atom anchored oxygen-rich defect 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 photo-driven controllable oxidation of HMF to DFF or FDCA, wherein 5-hydroxymethylfurfural and the above-mentioned Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst are subjected to photocatalytic oxidation reaction under 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 this invention can be carried out at room temperature, with mild reaction conditions, avoiding high temperature, high pressure and high pH reaction conditions, enabling controllable generation of reaction products, and the operation process is simple, with great application potential.

[0015] The Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst provided by this invention is rich in oxygen vacancies, effectively narrowing the band gap of TiO2 and enhancing its photoresponse range. Furthermore, the catalyst's unique structure significantly improves carrier separation capability and enhances the utilization of high-energy photons.

[0016] The Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst provided by this invention can efficiently utilize light energy to achieve controllable oxidation of HMF to DFF or FDCA, and the conversion rate of HMF does not decrease significantly during repeated use (5 times), showing good application prospects and economic benefits. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The X-ray diffraction patterns of different samples in Examples 1-3 of this invention are shown below.

[0019] Figure 2 These are Raman spectra of different samples in Examples 1-3 of this invention;

[0020] Figure 3 The near-edge and extended-edge spectra of Cu element in the Cu2 / TiO2 photocatalyst in Example 2 of this invention are shown.

[0021] Figure 4 The images show the X-ray photoelectron spectra of the Cu2 / TiO2 photocatalyst and P25 in Example 2 of the present invention, where 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 The electron spin resonance spectra of different samples in Examples 1-3 of this invention are shown.

[0023] Figure 6 The UV-Vis diffuse reflectance spectra of different samples in Examples 1-3 of this invention are shown.

[0024] Figure 7 Cu in Examples 4-9 of this invention x Experimental results of using TiO2 as a catalyst for the photocatalytic oxidation of HMF; where a represents Cu in the visible light system. x Experimental results of HMF photooxidation to DFF using TiO2 as a catalyst, where b represents Cu. 2 / The reusability results of TiO2 in the experiment of oxidizing HMF to DFF. c represents Cu in the simulated solar system. x Experimental results of HMF photooxidation to FDCA using TiO2 as a catalyst, where d represents Cu. 2 / Results of the reusability of TiO2 in the experiment of oxidizing HMF to FDCA. Detailed Implementation

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

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

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

[0030] In this invention, room temperature is defined as 15-35°C.

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

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

[0033] Ti-based metal-organic frameworks (denoted as MIL-125) were prepared by dissolving terephthalic acid and Ti precursor in solvent I and reacting them via a solvothermal reaction.

[0034] The Ti-based metal-organic framework was immersed in an aqueous solution of copper salt, followed by centrifugation and drying to obtain Cu-supported MIL-125 catalyst material (denoted as Cu-MIL-125);

[0035] Calcining the Cu-supported MIL-125 catalytic material yields the Cu single-atom anchored oxygen-rich defect 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 solvothermal reaction is 150-200°C, and the reaction time is 20-24 h.

[0037] In some embodiments of the present invention, solvent I is a mixed solvent composed 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-to-volume ratio of the Ti-based metal-organic framework to water in the aqueous solution of the copper salt is 1g:100-150mL, preferably 1g:120mL; the mass-to-volume ratio of the copper salt to water in the aqueous solution of the copper salt is 5-20mg:60mL.

[0039] In this invention, using copper salt at a concentration higher than the aforementioned parameters can lead to pore blockage of the catalyst, a decrease in the catalyst's specific surface area, and the formation of metal agglomerations into nanoclusters. This, in turn, reduces the number of active sites, hindering the diffusion and adsorption of reactants. Within the mass-to-volume ratio range of copper salt to water in this invention, the products obtained 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 copper salt, and the process further includes stirring or sonication to ensure that the Ti-based metal-organic framework is fully bonded to copper ions. The present invention does not impose special limitations on the parameters of stirring or sonication; conventional techniques skilled in the art can be used, such as stirring at room temperature for 1-6 hours.

[0041] In some embodiments of the present invention, before calcining the Cu-supported MIL-125 catalyst material, a step of grinding the Cu-supported MIL-125 catalyst 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 organic ligands through calcination.

[0043] In this invention, calcination temperatures and times below the aforementioned ranges result in organic ligands and N,N-dimethylformamide remaining in the pores of the catalyst without being sufficiently removed; temperatures and times above the aforementioned ranges cause titanium dioxide to undergo a phase transformation, forming a mixed anatase and rutile phase. Calcination of Cu-supported MIL-125 within the specified parameter ranges yields TiO2 that is entirely anatase phase.

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

[0045] 1. This invention first prepares a Ti-based metal-organic framework (MOF) via a solvothermal method. The MOF is then impregnated in an aqueous solution of a copper salt, followed by calcination to obtain a TiO2 catalyst loaded with Cu single atoms. Notably, by adjusting the ratio of tetrabutyl titanate to terephthalic acid during the preparation of the Ti-based MOF, a Ti-based MOF rich in Ti vacancies was successfully obtained. This ensures that Cu is supported during the impregnation process. 2+ The Cu is firmly adsorbed into the Ti vacancies, allowing the Cu obtained after subsequent calcination to be processed. x In the TiO2 catalyst, Cu exists in the form of single atoms, which avoids the aggregation of Cu atoms during high-temperature processing.

[0046] 2. The catalyst prepared by the method provided in this invention exhibits good stability. Specifically, in the single-atom catalyst prepared by this method, Cu atoms replace Ti atoms in the TiO2 lattice. 5c The Cu-O-Ti coordinate bonds are formed at the positions of the ions, rather than through simple adsorption, which ensures the high stability of the photocatalyst during use. Compared with catalysts prepared directly using commercial TiO2 through impregnation, photodeposition, and other methods, the catalyst prepared in this way is not only more stable but also rich in oxygen vacancies and has a high specific surface area, thus increasing the content of active sites.

[0047] 3. Cu prepared by optimizing synthesis conditions x The TiO2 catalyst exhibits superior selectivity in the catalytic reaction of 5-hydroxymethylfurfural. Specifically, in the photocatalytic oxidation reaction, 5-hydroxymethylfurfural is oxidized to 2,5-dicarboxyfuran under visible light conditions and to 2,5-furandicarboxylic acid under simulated sunlight conditions. Two oxidation products, rather than a single product, can be obtained by simply adjusting the light source, and high selectivity is achieved while maintaining high conversion rates.

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

[0049] The third technical solution of the present invention is the application of the above-mentioned Cu single-atom anchored oxygen-rich defect 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 photo-driven controllable oxidation of HMF to DFF or FDCA, wherein 5-hydroxymethylfurfural and the above-mentioned Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst are subjected to photocatalytic oxidation reaction under 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-dicarboxyfuran; 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 takes 1-7 hours.

[0053] This invention uses Cu x TiO2, as a photocatalyst, effectively utilizes high-energy photons to activate oxygen, achieving a conversion rate of 79.9%-95.2% for HMF in visible light systems (spectral range of 420-780 nm) and a yield of 71.4%-90.9% for DFF. In simulated sunlight systems (spectral range of 320-780 nm), the conversion rate of HMF reaches 90.4%-98.8%, and the yield of FDCA reaches 86.1%-98.2%. It can efficiently and selectively convert HMF to DFF or FDCA, showing promising application prospects.

[0054] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

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

[0056] Example 1

[0057] This preparation example provides a Cu1 / TiO2 photocatalyst for Cu single-atom anchored oxygen-rich TiO2 vacancy-enriched vacancy 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 mixture of N,N-dimethylformamide and methanol in a volume ratio of 9:1. The mixture was stirred to form a homogeneous solution, and then heat-treated at 160 °C for 20 h. After cooling, centrifugation, washing, and drying in a vacuum drying oven at 80 °C, a white powder was obtained, which was designated as MIL-125.

[0059] (2) 500 mg MIL-125 was dispersed in 60 mL of deionized water, and then 5 mg CuCl2·2H2O was added. The mixture was 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 drying oven at 80 °C, Cu-supported MIL-125 catalyst material was obtained, denoted as Cu-MIL-125.

[0060] (3) After grinding Cu-MIL-125 thoroughly, it was calcined at 500℃ for 4 hours to remove the organic ligands. The resulting material was labeled as Cu1 / TiO2.

[0061] Example 2

[0062] This preparation example provides a Cu single-atom anchored oxygen-rich TiO2 photocatalyst Cu2 / TiO2. The preparation method is the same as in Example 1, except that the amount of CuCl2·2H2O added is adjusted to 10 mg. The resulting catalyst is labeled Cu2 / TiO2.

[0063] Example 3

[0064] This preparation example provides a Cu single-atom anchored oxygen-rich TiO2 photocatalyst Cu3 / TiO2. The preparation method is the same as in Example 1, except that the amount of CuCl2·2H2O added is adjusted to 20 mg. The resulting catalyst is labeled Cu3 / TiO2.

[0065] Characterization results:

[0066] Cu obtained from Preparation Examples 1-3 x The 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-rich defect TiO2 photocatalyst, and each step of the preparation process was successful.

[0067] The Cu2 / TiO2 photocatalyst obtained in Preparation Example 2 was characterized by near-edge and extended-edge spectra of the Cu element at the K-side. Figure 3 It can be seen that Cu exists in the Cu2 / TiO2 photocatalyst prepared by this invention in the form of single atoms, which further proves that the preparation steps are successful.

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

[0069] Cu obtained from Preparation Examples 1-3 x Electron spin resonance characterization of / TiO2 photocatalyst, by Figure 5 It can be seen that the Cu prepared by this invention x / TiO2 photocatalysts are rich in oxygen vacancies.

[0070] Cu obtained from Preparation Examples 1-3 x The TiO2 photocatalyst was characterized by UV-Vis diffuse reflectance analysis. Figure 6 It can be seen that Cu single-atom anchoring increases the light absorption range of TiO2 photocatalyst into the visible light region.

[0071] Example 4

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

[0073] 10 mL of a 10 mmol / L acetonitrile solution of 5-hydroxymethylfurfural and 25 mg of the photocatalyst Cu1 / TiO2 from Example 1 were added to the reactor. A 300 W xenon lamp was used as the light source, and the spectral range was adjusted to 420-780 nm. The reaction was carried out at room temperature for 6 h. After the reaction was completed, the liquid phase product was detected by high performance liquid chromatography (HPLC). 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 the photocatalytic oxidation of HMF to DFF, which is the same as in Example 4, except that the photocatalyst Cu1 / TiO2 in Example 1 is replaced with the photocatalyst Cu2 / TiO2 in Example 2. HPLC analysis of the liquid-phase products showed a DFF yield of 90.9% and a selectivity of 95.5%, while the HMF conversion rate was 95.2%. Figure 7 ).

[0076] Example 6

[0077] This embodiment provides a method for the photocatalytic oxidation of HMF to DFF, which is the same as in Example 4, except that the photocatalyst Cu1 / TiO2 in Example 1 is replaced with the photocatalyst Cu3 / TiO2 in Example 3. HPLC analysis of the liquid-phase product showed a DFF yield of 68.5% and a selectivity of 89.3%, while the HMF conversion rate was 71.4%. Figure 7 ).

[0078] Example 7

[0079] This embodiment provides a method for the photocatalytic oxidation of HMF to FDCA, which is the same as in Example 4, except that the spectral range of the xenon lamp is adjusted to 320-780 nm, and the photoreaction is carried out for 7 hours. HPLC analysis of the liquid-phase products yielded an FDCA yield of 87.4% and a selectivity of 95.5%, while the HMF conversion rate was 91.5%. Figure 7 ).

[0080] Example 8

[0081] This embodiment provides a method for the photocatalytic oxidation of HMF to FDCA, which is the same as in Example 5, except that the spectral range of the xenon lamp is adjusted to 320-780 nm, and the photoreaction is carried out for 7 hours. HPLC analysis of the liquid-phase products showed that the yield of FDCA was 98.2%, the selectivity was 99.4%, and the conversion rate of HMF was 98.8%. Figure 7 ).

[0082] Example 9

[0083] This embodiment provides a method for the photocatalytic oxidation of HMF to FDCA, which is the same as in Example 6, except that the spectral range of the xenon lamp is adjusted to 320-780 nm, and the photoreaction is carried out for 7 hours. HPLC analysis of the liquid-phase products showed that the yield of FDCA was 86.1%, the selectivity was 95.2%, and the conversion rate of HMF was 90.4%. Figure 7 ).

[0084] In summary, this invention enables highly efficient photocatalytic selective conversion of HMF to DFF or FDCA, with both oxidation products yielding high added value. The method employs mild reaction conditions, utilizes a simple photocatalyst preparation process, and exhibits good stability, showing no significant decrease in catalytic activity even after five repeated uses. Therefore, this invention has promising application prospects.

[0085] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for light-driven controllable oxidation of HMF to DFF or FDCA, characterized in that, 5-hydroxymethylfurfural (HMF) and Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst were subjected to photocatalytic oxidation reaction under room temperature and oxygen conditions. When the spectral range is 420-780 nm in the visible light system, 5-hydroxymethylfurfural is selectively oxidized to 2,5-dicarboxyfuran (DFF); when the spectral range is 320-780 nm in the simulated sunlight system, 5-hydroxymethylfurfural is selectively oxidized to 2,5-furandicarboxylic acid (FDCA). The preparation method of the Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst includes the following steps: Ti-based metal-organic frameworks were prepared by dissolving terephthalic acid and Ti precursor in solvent I and reacting them via a solvothermal reaction. The Ti-based metal-organic framework was immersed in an aqueous solution of copper salt, followed by centrifugation and drying to obtain Cu-supported MIL-125 catalyst material; The Cu-supported MIL-125 catalytic material was calcined to obtain the Cu single-atom anchored oxygen-rich defect TiO2 photocatalyst. Solvent I is a mixed solvent composed of N,N-dimethylformamide and methanol; The mass-to-volume ratio of water in the aqueous solution of the Ti-based metal-organic framework and copper salt is 1 g: 100-150 mL; the mass-to-volume ratio of copper salt to water in the aqueous solution of copper salt is 5-20 mg: 60 mL. The calcination temperature is 400-500℃, and the time is 2-6 hours.

2. The method for controllable oxidation of HMF to DFF or FDCA by light-driven process 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 solvothermal reaction is 150-200℃, and the reaction time is 20-24h.

3. The method for controllable oxidation of HMF to DFF or FDCA by light-driven process according to claim 1, characterized in that, The copper salt is CuCl2·2H2O.

4. The method for controllable oxidation of HMF to DFF or FDCA by light-driven process according to claim 1, characterized in that, The photocatalytic oxidation reaction takes 1-7 hours.

Images