Method for preparing difuran monomer from biomass-based compound and metal / oxide composite material

Abstract

The invention provides a method for preparing a difuran monomer from a biomass-based compound, which comprises the following steps: mixing a metal / oxide photocatalyst material, a biomass-based compound solution and a reducing agent, and carrying out reductive coupling reaction under the atmosphere of protective gas by illumination to obtain the difuran monomer, the metal / oxide photocatalyst material comprises an oxide and a metal element loaded on the surface of the oxide. The invention further provides the metal / oxide composite material. The bimetal / oxygen vacancy modified oxide composite material is introduced as the catalyst for synthesizing the bifuran monomer, so that the preparation process of the bifuran monomer is simple (no complex equipment is needed), the reaction condition is mild, and the catalytic efficiency and selectivity are high; a novel path is provided for forming a high-added-value product from a biomass-based compound through a carbon-carbon bond, and the method has a wide industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic biomass value-added conversion technology, and in particular to a method for preparing bisfuran monomers from biomass-based compounds and a metal / oxide composite material. Background Technology

[0002] As the most abundant renewable energy source, biomass' efficient conversion into high-value-added chemicals (such as fine chemical intermediates and liquid fuels) has become a research hotspot. Photocatalysis technology, which can utilize clean energy (solar energy) to drive the reaction at room temperature, provides a green pathway for the value-added conversion of biomass.

[0003] Oxide semiconductors (such as ZnO, TiO2, CeO2, Fe2O3, SnO2, Al2O3, CuO, Cu2O, Cr2O3, MnO, V2O5, etc.) have attracted widespread attention as typical semiconductor photocatalysts due to their advantages such as low preparation cost and environmental friendliness. However, they have inherent defects: 1) Their wide bandgap makes them only respond to ultraviolet light, resulting in low solar energy utilization; 2) The fast recombination rate of photogenerated electron-hole pairs leads to poor charge separation efficiency; 3) They have few surface active sites and insufficient reducing power, making it difficult to drive carbon-carbon coupling reactions of biomass-based compounds.

[0004] To improve the performance of oxide semiconductors, existing technologies often employ single-metal loading (such as Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, Ir) or single-defect modification (such as oxygen vacancies). Single-metal loading can broaden the photoresponse range through surface plasmon resonance (SPR) effects, but the ability of a single metal to modulate the energy band is limited, and it cannot effectively solve the charge recombination problem. Single-defect modification of oxygen vacancies can introduce intermediate energy levels to capture electrons, but lacks efficient electron transport pathways, resulting in insufficient reducibility of active sites. In addition, existing catalysts exhibit low reductive coupling selectivity for biomass-based compounds, especially for substrates containing heteroatoms (such as furan rings), which are prone to side reactions (such as oxidation and dehalogenation), thus affecting the purity of biomass-based compounds.

[0005] Therefore, developing a metal / oxide-based photocatalytic material that can simultaneously achieve wide bandgap narrowing, efficient charge separation, and the construction of highly reducing active sites is of great significance for promoting the industrialization of biomass value-added conversion. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a method for preparing bisfuran monomers from biomass-based compounds. This method solves the problems of wide bandgap, high charge recombination rate, and insufficient reduction activity of metal oxide semiconductors by using the bimetallic synergistic and oxygen vacancy synergistic effects of the catalyst. The metal / oxide photocatalytic material is used as a catalyst for the reductive coupling reaction of biomass-based compounds, thus achieving the synthesis of bisfuran monomers with high selectivity and high efficiency.

[0007] In view of this, this application provides a method for preparing bisfuran monomers from biomass-based compounds, comprising:

[0008] Metal / oxide photocatalyst material, biomass-based compound solution and reducing agent are mixed and subjected to reduction coupling reaction under light irradiation in a protective gas atmosphere to obtain bisfuran monomer;

[0009] The metal / oxide photocatalyst material comprises an oxide and a metal element supported on the surface of the oxide. The metal element includes at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir. The oxide includes one or two of Ov-ZnO, Ov-TiO2, Ov-CeO2, Ov-Fe2O3, Ov-SnO2, Ov-Al2O3, Ov-CuO, Ov-Cu2O, Ov-Cr2O3, Ov-MnO, and Ov-V2O5.

[0010] In some specific embodiments, the biomass-based compound includes furan benzyl chloride, ethyl ester-substituted benzyl chloride, amide-substituted benzyl chloride, furan benzyl bromide, or methyl p-chloromethylbenzoate.

[0011] In some specific embodiments, the solvent in the biomass-based compound solution includes one or more of isopropanol, water, 3-pentanol, 2,4-dimethyl-3-pentanol, tetrahydrofuran, acetonitrile, and dimethylformamide.

[0012] In some specific embodiments, the solvent in the biomass-based compound solution is selected from a mixed solution of isopropanol and water, a mixed solution of 3-pentanol and water, or a mixed solution of 2,4-dimethyl-3-pentanol and water.

[0013] In some specific embodiments, the reducing agent includes one or more of isopropanol, methanol, cyclohexanol, ethanol, benzyl alcohol, and furfuryl alcohol.

[0014] In some specific embodiments, the protective gas atmosphere is a 1-3 bar argon atmosphere, and / or the light source is a 365 nm ultraviolet lamp or 365 nm simulated sunlight.

[0015] In some specific embodiments, the metal / oxide photocatalyst material is a Cu-Au / Ov-ZnO heterojunction photocatalyst, and the preparation method of the Cu-Au / Ov-ZnO heterojunction photocatalyst includes the following steps:

[0016] Oxygen vacancies were constructed in ZnO nanoparticles by chemical reduction to obtain Ov-ZnO;

[0017] Au-Cu bimetallic nanoparticles were loaded onto the surface of Ov-ZnO by photodeposition and dried to obtain a Cu-Au / Ov-ZnO heterojunction photocatalyst.

[0018] In the Cu-Au / Ov-ZnO heterojunction photocatalyst, the loading of Au in Ov-ZnO is 2~3wt%, and the loading of Cu in Ov-ZnO is 1~3wt%.

[0019] In some specific embodiments, the preparation method of the Ov-ZnO is as follows:

[0020] ZnO nanoparticles were dispersed in water and subjected to ultrasonic treatment to obtain a suspension;

[0021] Under anhydrous and oxygen-free conditions, NaBH4 aqueous solution was added to the suspension for reduction while it was being stirred to obtain Ov-ZnO;

[0022] The specific steps for obtaining the Cu-Au / Ov-ZnO heterojunction photocatalyst are as follows:

[0023] Ov-ZnO was dispersed in a solvent, and then copper source solution and gold source solution were added. The mixture was irradiated with 365nm light for 1-3 hours under anhydrous and oxygen-free conditions to obtain Cu-Au / Ov-ZnO heterojunction photocatalyst.

[0024] In some specific embodiments, the specific surface area of ​​the Cu-Au / Ov-ZnO heterojunction photocatalyst is not less than 16.5 m². 2 / g.

[0025] This application also provides a metal / oxide composite material, comprising an oxide and a metal element supported on the surface of the oxide, wherein the metal element comprises at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir, and the oxide comprises one or two of Ov-ZnO, Ov-TiO2, Ov-CeO2, Ov-Fe2O3, Ov-SnO2, Ov-Al2O3, Ov-CuO, Ov-Cu2O, Ov-Cr2O3, Ov-MnO, and Ov-V2O5.

[0026] This application provides a method for preparing bisfuran monomers from biomass-based compounds. The method involves mixing a metal / oxide photocatalyst material, a biomass-based compound solution, and a reducing agent, followed by a reduction coupling reaction under light irradiation in a protective gas atmosphere to obtain the bisfuran monomers. In the preparation of the bisfuran monomers, this application uses a metal / oxide photocatalyst material as the catalyst. The introduction of bimetals into the photocatalyst material synergistically modulates the energy band, broadens the photoresponse range, and significantly improves the utilization rate of ultraviolet-visible light. The introduction of oxide oxygen vacancies in the photocatalyst material enhances electron supply, constructs charge transport channels at the metal-oxygen bond interface of the catalyst material, increases the average lifetime of photogenerated carriers, and reduces the charge recombination rate. Simultaneously, the introduction of oxygen vacancies exposes more active sites. Therefore, the introduction of a metal / oxide photocatalyst in this application significantly enhances the photogenerated electron reduction capability, efficiently drives the carbon-carbon bond coupling of the biomass-based compound, and achieves the synthesis of highly selective and efficient bisfuran monomers. Attached Figure Description

[0027] Figure 1 a) TEM image, b) Au elemental analysis and c) Cu elemental analysis diagram of CuAu / Ov-ZnO prepared for embodiments of the present invention;

[0028] Figure 2 Cu2 / ZnO, Au2 / ZnO, and Cu2-Au prepared for embodiments of the present invention 2.6 / ZnO and Cu2-Au 2.6 a) UV-vis images and b) Tauc images of / Ov-ZnO;

[0029] Figure 3 Cu2-Au prepared for embodiments of the present invention 2.6 / ZnO and Cu2-Au 2.6 a) PL and b) TRPL images of / Ov-ZnO;

[0030] Figure 4 Cu2-Au prepared for embodiments of the present invention 2.6 / ZnO and Cu2-Au 2.6 a) BET image and b) EPR image of / Ov-ZnO. Detailed Implementation

[0031] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0032] In view of the shortcomings of existing oxide semiconductor photocatalyst materials in the synthesis of bisfuran monomers, this application provides a method for preparing bisfuran monomers from biomass-based compounds. This method solves the problems of wide bandgap, high charge recombination rate, and insufficient reduction activity of ZnO by employing a metal / oxide photocatalyst material possessing both bimetallic and oxygen vacancies, achieving highly selective and efficient carbon-carbon bond formation. Furthermore, the method provided in this application simplifies the preparation process of bisfuran monomers and reduces equipment requirements. Specifically, this application provides a method for preparing bisfuran monomers from biomass-based compounds, comprising:

[0033] Metal / oxide photocatalyst material, biomass-based compound solution and reducing agent are mixed and subjected to reduction coupling reaction under light irradiation in a protective gas atmosphere to obtain bisfuran monomer;

[0034] The metal / oxide photocatalyst material comprises an oxide and a metal element supported on the surface of the oxide. The metal element includes at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir. The oxide includes one or two of Ov-ZnO, Ov-TiO2, Ov-CeO2, Ov-Fe2O3, Ov-SnO2, Ov-Al2O3, Ov-CuO, Ov-Cu2O, Ov-Cr2O3, Ov-MnO, and Ov-V2O5.

[0035] In the process of preparing bisfuran monomers from the biomass-based compounds provided in this application, the biomass-based compounds include furan benzyl chloride, ethyl ester-substituted benzyl chloride, amide-substituted benzyl chloride, furan benzyl bromide, or methyl p-chloromethylbenzoate. The solute in the biomass-based compound solution includes one or more of isopropanol, water, 3-pentanol, 2,4-dimethyl-3-pentanol, tetrahydrofuran, acetonitrile, and dimethylformamide; specifically, the solute in the biomass-based compound solution is selected from a mixed solution of isopropanol and water, a mixed solution of 3-pentanol and water, or a mixed solution of 2,4-dimethyl-3-pentanol and water; more specifically, the solute in the biomass-based compound solution is selected from a mixed solution of isopropanol and water, which results in a higher rate of bisfuran monomer formation.

[0036] In the above process, the reducing agent includes one or more of isopropanol, methanol, cyclohexanol, ethanol, benzyl alcohol and furfuryl alcohol. Specifically, the reducing agent is selected from isopropanol, methanol, cyclohexanol, ethanol, benzyl alcohol and furfuryl alcohol. More specifically, the reducing agent is selected from isopropanol.

[0037] The metal / oxide photocatalytic material of this application comprises an oxide and a metal element supported on the surface of the oxide, wherein the oxide includes Ov-ZnO (oxygen vacancy modified ZnO), Ov-TiO2 (oxygen vacancy modified TiO2), Ov-CeO2 (oxygen vacancy modified CeO2), Ov-Fe2O3 (oxygen vacancy modified Fe2O3), Ov-SnO2 (oxygen vacancy modified SnO2), Ov-Al2O3 (oxygen vacancy modified Al2O3), and Ov-CuO (oxygen vacancy modified CuO). The oxide is selected from one or two of the following: Ov-Cu2O (oxygen vacancy modified Cu2O), Ov-Cr2O3 (oxygen vacancy modified Cr2O3), Ov-MnO (oxygen vacancy modified MnO), and Ov-V2O5 (oxygen vacancy modified V2O5); specifically, the oxide is selected from one of Ov-ZnO, Ov-TiO2, Ov-CeO2, Ov-Fe2O3, Ov-SnO2, Ov-Al2O3, Ov-CuO, Ov-Cu2O, Ov-Cr2O3, Ov-MnO, and Ov-V2O5. The metal element includes at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir. Specifically, the metal element is selected from at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir. More specifically, the metal element is selected from Cu and Au.

[0038] The metal / oxide photocatalyst material is a Cu-Au / Ov-ZnO heterojunction photocatalyst, and the preparation method of the Cu-Au / Ov-ZnO heterojunction photocatalyst includes the following steps:

[0039] Oxygen vacancies were constructed in ZnO nanoparticles by chemical reduction to obtain Ov-ZnO;

[0040] Au-Cu bimetallic nanoparticles were loaded onto the surface of Ov-ZnO by photodeposition and dried to obtain a Cu-Au / Ov-ZnO heterojunction photocatalyst.

[0041] In the Cu-Au / Ov-ZnO heterojunction photocatalyst, the loading of Au in Ov-ZnO is 2~3wt%, and the loading of Cu in Ov-ZnO is 1~3wt%.

[0042] More specifically, the preparation method of the Cu-Au / Ov-ZnO heterojunction photocatalyst includes the following steps:

[0043] ZnO nanoparticles were dispersed in water and subjected to ultrasonic treatment to obtain a suspension;

[0044] Under anhydrous and oxygen-free conditions, NaBH4 aqueous solution was added to the suspension for reduction while it was being stirred to obtain Ov-ZnO;

[0045] Ov-ZnO was dispersed in a solvent, and then copper source solution and gold source solution were added. The mixture was irradiated with 365nm light for 1-3 hours under anhydrous and oxygen-free conditions to obtain Cu-Au / Ov-ZnO heterojunction photocatalyst.

[0046] In this application, when other metal elements and oxides are selected in the metal / oxide photocatalytic material, the preparation method is basically the same as the preparation method of the Cu-Au / Ov-ZnO heterojunction photocatalyst described above.

[0047] In this application, a metal / oxide photocatalyst material is suspended in a mixture of reaction substrate and reducing agent, and then irradiated in a protective gas atmosphere, specifically a 1-3 bar argon atmosphere. The irradiation uses a 365 nm light source, specifically an ultraviolet lamp or simulated sunlight.

[0048] Furthermore, the method for preparing bisfuran monomers from biomass-based compounds using Cu-Au / Ov-ZnO heterojunction photocatalytic materials as catalysts is as follows:

[0049] 0.01 mol zinc nitrate hexahydrate and 0.01 mol oxalic acid were dissolved in 100 mL of deionized water respectively. The oxalic acid solution was slowly added dropwise to the zinc nitrate solution to form zinc oxalate precipitate. After standing for 2 h, the precipitate was filtered, washed three times with deionized water, dried at 60 °C for 12 h, ground into powder, and placed in a muffle furnace. The temperature was increased to 350 °C over 3 h and calcined for 6 h to obtain ZnO nanoparticles.

[0050] 0.5 g ZnO nanoparticles were dispersed in 25 mL of deionized water and sonicated for 40 min to form a uniform suspension. Under anhydrous and oxygen-free conditions, 25 mL of NaBH4 aqueous solution (containing 0.5 g NaBH4) was added while stirring vigorously, and stirring was continued for 2 h to complete the reduction. After filtration, the precipitate was washed three times with deionized water and dried at 50 ℃ for 12 h to obtain Ov-ZnO.

[0051] 200 mg of Ov-ZnO was dispersed in a mixed solvent of 30 mL deionized water and 10 mL methanol. A copper nitrate solution with a Cu loading of 2 wt% and a chloroauric acid solution with an Au loading of 2.6 wt% were added. The mixture was irradiated with a 365 nm light source for 2 h under anhydrous and oxygen-free conditions. After the reaction, the mixture was filtered, the precipitate was washed three times with deionized water, and dried at 60 ℃ for 12 h to obtain the Cu-Au / Ov-ZnO heterojunction photocatalytic material.

[0052] At room temperature, 10 mg of Cu-Au / Ov-ZnO catalyst was suspended in a mixture of 10 mL substrate solution and reducing agent. Before the reaction, the mixture was purged with argon for 30 min to remove oxygen and then irradiated with a 365 nm light source under an argon atmosphere of 1 bar for 2 h.

[0053] This application also provides a metal / oxide composite material, comprising an oxide and a metal element supported on the surface of the oxide, wherein the metal element comprises at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir, and the oxide comprises one or two of Ov-ZnO, Ov-TiO2, Ov-CeO2, Ov-Fe2O3, Ov-SnO2, Ov-Al2O3, Ov-CuO, Ov-Cu2O, Ov-Cr2O3, Ov-MnO, and Ov-V2O5.

[0054] The metal / oxide composite material provided in this application, taking Cu-Au / Ov-ZnO heterojunction photocatalyst as an example, has the following advantages:

[0055] 1) Bimetallic synergistic bandgap modulation to broaden the photoresponse range: The SPR effect of Au (broad absorption peak at 520-600 nm as shown in UV-Vis) and the dd electron transition of Cu (continuous absorption at 400-700 nm) work synergistically to narrow the band gap of Cu-Au / Ov-ZnO to 3.13 eV (calculated by Tauc plot). Compared with pure ZnO (3.20 eV) and single-metal-loaded Cu / ZnO (3.18 eV), the UV-Vis light utilization rate is improved by more than 40%.

[0056] 2) Oxygen vacancies enhance electron supply and optimize charge separation: Oxygen vacancies introduced by NaBH4 reduction (strong signal at g=2.003 verified by EPR) construct a bulk electric field, promoting electron migration from the ZnO bulk phase to the surface; simultaneously, the interfacial metal-oxygen bonds (XPS shows a 2.3 eV reduction in Cu 2p binding energy, with Au forming a coordinate bond with O) construct charge transport channels, increasing the average lifetime of photogenerated carriers from 3.6953 ns without Ov to 5.9823 ns (TRPL test), and reducing the charge recombination rate by 60%.

[0057] 3) High specific surface area and strong reducing active sites: Oxygen vacancy etching makes the specific surface area of ​​Cu-Au / Ov-ZnO reach 16.5771 m² / g (BET test), which is 1.26 times that of CuAu / ZnO without Ov modification (13.1772 m² / g), exposing more active sites; in addition, Mott-Schottky test shows that its flat band potential is -0.7 V (higher than -0.52 V of CuAu / ZnO without Ov modification), proving that the photogenerated electron reduction ability is significantly enhanced, which can efficiently drive carbon-carbon bond coupling.

[0058] The method for preparing difuran monomers from biomass-based compounds provided by this invention has the following significant advantages:

[0059] 1) High catalytic efficiency: Under optimized conditions, the efficiency of catalytic reduction coupling of furan benzyl chloride reaches 2625.0 μmol·g. -1 ·h -1 This is significantly higher than the following comparative samples: pure ZnO (≈0), Cu / ZnO (656.25 μmol·g⁻¹). -1 ·h -1 ), Cu / Ov-ZnO (1562.5 μmol·g -1 ·h -1 ), CuAu / ZnO (1968.8 μmol·g -1 ·h -1 ), and is superior to noble metal supported catalysts such as Pd (1562.5 μmol·g). -1 ·h -1 ).

[0060] 2) Broad substrate applicability: Maintains high activity on various biomass substrates: furazolidone (2562.0 μmol·g) -1 ·h -1 ), methyl 4-(chloromethyl) benzoate (1875.0 μmol·g -1 ·h -1 ), ethyl ester-substituted benzyl chloride (2500.0 μmol·g) -1 ·h -1 Only for amide-substituted benzyl chloride (1438.0 μmol·g) -1 ·h -1 The slight decrease indicates good compatibility with different functional groups;

[0061] 3) High selectivity and stability: The target product (such as furanylbenzyl) in the reaction has high selectivity and no obvious by-products (such as dehalogenation and oxidation products); after the catalyst is recycled 5 times, the catalytic efficiency still remains above 85% of the initial value (XRD shows no change in crystal phase, and ICP-MS detects metal dissolution of <0.1 mg / L).

[0062] Furthermore, the method provided in this application has a simple preparation process: it does not require high-temperature and high-pressure equipment, and all steps (precipitation, reduction, and photodeposition) are completed under conventional laboratory conditions. The raw materials (zinc nitrate, oxalic acid, and NaBH4) are low in cost and easy to scale up for production. The reaction conditions are mild: the reaction is carried out at room temperature and normal pressure, and the light source is a low-cost 365 nm ultraviolet lamp (which can be replaced by simulated sunlight). No additional heating or pressurization is required, resulting in low energy consumption. The reaction is green and environmentally friendly: the reaction uses water-methanol as a mixed solvent and does not contain toxic organic solvents (such as THF and DMF, which, according to the document, produce almost no products). In addition, the argon atmosphere can prevent oxygen from participating in side reactions, and the product separation is simple, meeting the requirements of green chemistry.

[0063] To further understand the present invention, the method for preparing bisfuran monomers from biomass-based compounds provided by the present invention will be described in detail below with reference to embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0064] Example 1 Cu2-Au 2.6 Preparation of / Ov-ZnO

[0065] ZnO synthesis: 0.01 mol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.01 mol oxalic acid (H2C2O4) were dissolved separately in 100 mL of deionized water and stirred until completely dissolved. The oxalic acid solution was slowly added dropwise to the zinc nitrate solution at a rate of 1 drop / second while stirring (300 rpm). After the addition was complete, stirring was continued for 30 min, and the mixture was allowed to stand for 2 h to form a white zinc oxalate precipitate. The precipitate was collected by filtration and washed three times with deionized water (until the pH of the filtrate was 7). The precipitate was then vacuum dried at 60 ℃ for 12 h and ground into a fine powder. The powder was placed in a muffle furnace and heated (3 ℃ / min) to 350 ℃ and calcined at this temperature for 6 h. After naturally cooling to room temperature, white ZnO nanoparticles were obtained.

[0066] Ov-ZnO Synthesis: 0.5 g of the above ZnO nanoparticles were weighed and dispersed in 25 mL of deionized water. The mixture was sonicated for 40 min (300 W) to form a uniform suspension. The suspension was transferred to a three-necked flask and argon gas was introduced for 30 min to create an anhydrous and oxygen-free environment. Under vigorous stirring (500 rpm), 25 mL of NaBH4 aqueous solution (containing 0.5 g of NaBH4, freshly prepared) was slowly added dropwise. After the addition was completed, stirring was continued for 2 h to ensure complete reduction. The precipitate was collected by filtration, washed three times with deionized water, and dried under vacuum at 50 °C for 12 h to obtain light gray Ov-ZnO powder (oxygen vacancy modified ZnO).

[0067] Cu2-Au 2.6 / Ov-ZnO synthesis: 200 mg Ov-ZnO powder was dispersed in a mixed solvent of 30 mL deionized water and 10 mL methanol (V 水 V 甲醇 In a 3:1 ratio, a suspension was formed by sonication for 10 min. 2 wt% copper nitrate (Cu(NO3)2·3H2O) solution and 2.6 wt% chloroauric acid (HAuCl4·4H2O) solution were added to the suspension, and the mixture was stirred for 10 min before being transferred to a photoreactor. Argon gas was introduced for 30 min to purge oxygen. A 365 nm ultraviolet light source (100 W) was turned on, and photodeposition was performed under illumination for 2 h, with stirring maintained at 300 rpm. After the reaction, the mixture was filtered, the precipitate was washed three times with deionized water, and then vacuum dried at 60 ℃ for 12 h to obtain a brownish-yellow Cu2-Au. 2.6 / Ov-ZnO heterojunction photocatalytic material.

[0068] Figure 1 Cu2-Au prepared in this embodiment 2.6 a) TEM image, b) Au elemental analysis spectrum, and c) Cu elemental analysis spectrum of the / Ov-ZnO heterojunction photocatalytic material, by Figure 1 It can be seen that Cu and Au elements are loaded on the Ov-ZnO surface.

[0069] Example 2 Preparation of Cu2 / ZnO and Au2 / ZnO

[0070] ZnO synthesis: 0.01 mol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.01 mol oxalic acid (H2C2O4) were dissolved separately in 100 mL of deionized water and stirred until completely dissolved. The oxalic acid solution was slowly added dropwise to the zinc nitrate solution at a rate of 1 drop / second while stirring (300 rpm). After the addition was complete, stirring was continued for 30 min, and the mixture was allowed to stand for 2 h to form a white zinc oxalate precipitate. The precipitate was collected by filtration and washed three times with deionized water (until the pH of the filtrate was 7). The precipitate was then vacuum dried at 60 ℃ for 12 h and ground into a fine powder. The powder was placed in a muffle furnace and heated (3 ℃ / min) to 350 ℃ and calcined at this temperature for 6 h. After naturally cooling to room temperature, white ZnO nanoparticles were obtained.

[0071] Cu2 / ZnO synthesis: 200 mg ZnO nanoparticles were dispersed in a mixed solvent of 30 mL deionized water and 10 mL methanol (V... 水 V 甲醇 In a 3:1 ratio, a suspension was formed by sonication for 10 min. A 2 wt% copper nitrate (Cu(NO3)2·3H2O) solution was added to the suspension, and after stirring for 10 min, the mixture was transferred to a photoreactor. Argon gas was introduced for 30 min to remove oxygen. A 365 nm ultraviolet light source (100 W power) was turned on, and photodeposition was performed under illumination for 2 h, with stirring maintained at 300 rpm. After the reaction, the mixture was filtered, the precipitate was washed three times with deionized water, and then vacuum dried at 60 ℃ for 12 h to obtain a brownish-yellow Cu2 / ZnO photocatalytic material.

[0072] Au2 / ZnO synthesis: 200 mg of ZnO nanoparticles were dispersed in a mixed solvent of 30 mL deionized water and 10 mL methanol (V... 水 V 甲醇 In a 3:1 ratio, a suspension was formed by sonication for 10 min. 2 wt% chloroauric acid (HAuCl4·4H2O) solution was added to the suspension, and after stirring for 10 min, the mixture was transferred to a photoreactor. Argon gas was introduced for 30 min to remove oxygen. A 365 nm ultraviolet light source (100 W power) was turned on, and photodeposition was performed under illumination for 2 h, with stirring maintained at 300 rpm. After the reaction, the mixture was filtered, the precipitate was washed three times with deionized water, and vacuum dried at 60 ℃ for 12 h to obtain a brownish-yellow Au2 / ZnO photocatalytic material.

[0073] Example 3 Cu2-Au 2.6 Preparation of ZnO

[0074] ZnO synthesis: 0.01 mol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.01 mol oxalic acid (H2C2O4) were dissolved separately in 100 mL of deionized water and stirred until completely dissolved. The oxalic acid solution was slowly added dropwise to the zinc nitrate solution at a rate of 1 drop / second while stirring (300 rpm). After the addition was complete, stirring was continued for 30 min, and the mixture was allowed to stand for 2 h to form a white zinc oxalate precipitate. The precipitate was collected by filtration and washed three times with deionized water (until the pH of the filtrate was 7). The precipitate was then vacuum dried at 60 ℃ for 12 h and ground into a fine powder. The powder was placed in a muffle furnace and heated (3 ℃ / min) to 350 ℃ and calcined at this temperature for 6 h. After naturally cooling to room temperature, white ZnO nanoparticles were obtained.

[0075] Cu2-Au 2.6 / ZnO synthesis: 200 mg ZnO nanoparticles were dispersed in a mixed solvent of 30 mL deionized water and 10 mL methanol (V 水 V 甲醇 In a 3:1 ratio, a suspension was formed by sonication for 10 min. 2 wt% copper nitrate (Cu(NO3)2·3H2O) solution and 2.6 wt% chloroauric acid (HAuCl4·4H2O) solution were added to the suspension, and the mixture was stirred for 10 min before being transferred to a photoreactor. Argon gas was introduced for 30 min to purge oxygen. A 365 nm ultraviolet light source (100 W) was turned on, and photodeposition was performed under illumination for 2 h, with stirring maintained at 300 rpm. After the reaction, the mixture was filtered, the precipitate was washed three times with deionized water, and then vacuum dried at 60 ℃ for 12 h to obtain a brownish-yellow Cu2-Au. 2.6 / ZnO heterojunction photocatalytic materials.

[0076] Figure 2 Cu2 / ZnO, Au2 / ZnO, and Cu2-Au prepared for the above embodiments 2.6 / ZnO and Cu2-Au 2.6 a) UV-vis images and b) Tauc images of / Ov-ZnO; by Figure 2 It can be seen that the absorption intensity of ultraviolet-visible light is Cu2-Au 2.6 / Ov-ZnO>Cu2 / ZnO≈Au2 / ZnO>ZnO; Au2 / ZnO exhibits a broad absorption peak in the 520–600 nm range, attributed to the surface plasmon resonance (SPR) effect of Au nanoparticles, with its peak position (~550 nm) consistent with typical SPR characteristics of Au nanoparticles; Cu2 / ZnO shows continuous absorption enhancement in the 400–700 nm range, originating from dd electron transitions in Cu species and possible contributions from the narrow bandgap of CuO (indirect bandgap ~1.7 eV); Cu2-Au 2.6The / Ov-ZnO (bimetallic system) simultaneously retains the SPR peak of Au (~550 nm) and the broad-spectrum absorption of Cu, with significantly higher absorption intensity in the 450–650 nm range compared to the monometallic system, confirming that the synergistic effect of the bimetallic system broadens the visible light response range. Furthermore, based on the relationship between the absorption coefficient (R) and photon energy (hv): αhv = A(hv - Eg) 2 Where hv and A represent the discrete photon energy and absorption constant of the direct transition, respectively, and A is a material-dependent constant. By using (Ahv) 2 Extrapolate the linear portion of the (hv) curve to (Ahv) 2 =0, the measured electronic band gap (Eg) of the sample was 3.14 eV (Cu2-Au). 2.6 / Ov-ZnO), 3.16 eV (Cu2 / ZnO), 3.19 eV (Au2 / ZnO) and 3.21 eV (ZnO).

[0077] Figure 3 Cu2-Au prepared for the above embodiments 2.6 / ZnO and Cu2-Au 2.6 a) PL and b) TRPL images of / Ov-ZnO; by Figure 3 It can be seen that the PL image indicates Cu2-Au 2.6 The quenching efficiency of the Ov defect peak at 400–600 nm in / Ov-ZnO is significantly improved, indicating that Ov acts as an efficient electron trap to suppress radiative recombination, which is consistent with the results of UV-Vis spectroscopy. As shown in the TRPL image, Ov modification increases the average lifetime of photogenerated carriers from 3.6953 ns to 5.9823 ns, which improves the theoretical quantum efficiency by about 1.6 times, proving that Ov suppresses carrier recombination.

[0078] Figure 4 Cu2-Au prepared for the above embodiments 2.6 / ZnO and Cu2-Au 2.6 a) BET image and b) EPR image of / Ov-ZnO; by Figure 4 It can be seen that both curves in the BET plot exhibit type IV isotherms (IUPAC classification), and a distinct H3-type hysteresis loop appears in the P / P0 = 0.4~0.9 range, indicating that the material has: a mesoporous dominant structure (pore size 2~50 nm); slit-like channels (originating from the accumulation of plate-like particles or layered structure); the hysteresis loop closure point is located at P / P0≈0.42, which is consistent with the characteristics of typical mesoporous materials, verifying the porous nature of the ZnO matrix and conforming to SEM characterization; EPR analysis shows the EPR signal intensity generated by the capture of single electrons by surface Ov at g=2.003; compared with the sample Cu2-Au 2.6 / ZnO,Cu2-Au2.6 The signal intensity of / Ov-ZnO is three times that of / Ov-ZnO, confirming that oxygen vacancies have successfully introduced a high concentration of defects.

[0079] Example 4 Preparation of Cu2 / Ov-ZnO

[0080] ZnO synthesis: 0.01 mol zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 0.01 mol oxalic acid (H2C2O4) were dissolved separately in 100 mL of deionized water and stirred until completely dissolved. The oxalic acid solution was slowly added dropwise to the zinc nitrate solution at a rate of 1 drop / second while stirring (300 rpm). After the addition was complete, stirring was continued for 30 min, and the mixture was allowed to stand for 2 h to form a white zinc oxalate precipitate. The precipitate was collected by filtration and washed three times with deionized water (until the pH of the filtrate was 7). The precipitate was then vacuum dried at 60 ℃ for 12 h and ground into a fine powder. The powder was placed in a muffle furnace and heated (3 ℃ / min) to 350 ℃ and calcined at this temperature for 6 h. After naturally cooling to room temperature, white ZnO nanoparticles were obtained.

[0081] Ov-ZnO Synthesis: 0.5 g of the above ZnO nanoparticles were weighed and dispersed in 25 mL of deionized water. The mixture was sonicated for 40 min (300 W) to form a uniform suspension. The suspension was transferred to a three-necked flask and argon gas was introduced for 30 min to create an anhydrous and oxygen-free environment. Under vigorous stirring (500 rpm), 25 mL of NaBH4 aqueous solution (containing 0.5 g of NaBH4, freshly prepared) was slowly added dropwise. After the addition was completed, stirring was continued for 2 h to ensure complete reduction. The precipitate was collected by filtration, washed three times with deionized water, and dried under vacuum at 50 °C for 12 h to obtain light gray Ov-ZnO powder (oxygen vacancy modified ZnO).

[0082] Cu2 / Ov-ZnO synthesis: 200 mg of Ov-ZnO powder was dispersed in a mixed solvent of 30 mL deionized water and 10 mL methanol (V... 水 V 甲醇 In a mixture of Cu2 / Ov-ZnO and Cu2O (3:1), a suspension was formed by sonication for 10 min. A 2 wt% copper nitrate (Cu(NO3)2·3H2O) solution was added to the suspension, and the mixture was stirred for 10 min before being transferred to a photoreactor. Argon gas was introduced for 30 min to remove oxygen. A 365 nm ultraviolet light source (100 W) was turned on, and photodeposition was performed under illumination for 2 h, with stirring maintained at 300 rpm. After the reaction, the mixture was filtered, the precipitate was washed three times with deionized water, and vacuum dried at 60 ℃ for 12 h to obtain a brownish-yellow Cu2 / Ov-ZnO heterojunction photocatalytic material.

[0083] Example 4: Reductive Coupling Reaction of Furan Benzyl Chloride

[0084] Reaction system configuration: 10 mg of Cu2 / ZnO, Au2 / ZnO, Cu2 / Ov-ZnO, and Cu2-Au prepared in the above examples. 2.6 / ZnO、Cu2-Au 2.6 The / Ov-ZnO catalyst was mixed with 10 mL of substrate solution (10 mM furan benzyl chloride, 2.5 mL isopropanol and 2.5 mL H2O) and transferred to a 50 mL sealed glass bottle;

[0085] Reaction procedure: Purging with argon for 30 min (flow rate 20 mL / min), irradiated with a 365 nm light source (100 W) for 2 h in an argon atmosphere of 1 bar, and stirred at a stirring rate of 300 rpm to carry out the reduction coupling reaction;

[0086] Product analysis: The obtained product was centrifuged to separate the catalyst. The supernatant was filtered through a 0.22 μm filter membrane and analyzed by GC-MS (column: HP-5MS, carrier gas: helium, temperature program: 80 ℃ for 2 min, 10 ℃ / min to 250 ℃, hold for 5 min) to determine the formation rate of furazolidone. The results are shown in Table 1.

[0087] Table 1. Generation rate data of different catalysts for furanylbenzyl

[0088]

[0089] Cu2-Au 2.6 After being recycled 5 times in the above reaction system, the / Ov-ZnO generation rate can still reach 80% of that of the first use.

[0090] Example 5

[0091] The furanylbenzyl chloride reduction coupling reaction is basically the same as in Example 4, except that the catalyst is Cu2-Au. 2.6 The solvent of the substrate solution for the / Ov-ZnO catalyst was adjusted, as shown in Table 2. The formation rate of furanylbenzyl is shown in Table 2.

[0092] Table 2. Generation rate data of different solvents for furanylbenzyl

[0093]

[0094] As shown in Table 2, the reaction efficiency is highest when isopropanol + water is used as the solvent. This is because short-chain alcohols have high solubility in water and low steric hindrance, which facilitates contact between the substrate and the active site of the catalyst. Long-chain alcohols (such as 3-pentanol) have lower efficiency due to increased steric hindrance. Aprotic solvents (THF, MeCN, DMF) result in extremely low efficiency.

[0095] Example 6

[0096] The reductive coupling reaction is basically the same as in Example 4, except that the biomass-based compounds are changed to methyl 5-bromomethylfurfural, ethyl 5-chloromethylfurfural, 5-chloromethyl-N,N-dimethylfuran-2-carboxamide, and 1-chloromethyl-4-methylperoxybenzene. The reaction formulas for the reductive coupling reaction are shown below, and the reaction rates are shown in Table 3.

[0097]

[0098]

[0099] Table 3. Generation rate data of different biomass-based compounds

[0100]

[0101] Example 7

[0102] The reductive coupling reaction is basically the same as in Example 4, except that the catalyst is replaced as shown in Table 4, and the corresponding reaction rates are shown in Table 4.

[0103] Table 4. Generation rate data for different catalysts

[0104]

[0105] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0106] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing bisfuran monomers from biomass-based compounds, comprising: Metal / oxide photocatalyst material, biomass-based compound solution and reducing agent are mixed and subjected to reduction coupling reaction under light irradiation in a protective gas atmosphere to obtain bisfuran monomer; The metal / oxide photocatalyst material comprises an oxide and a metal element supported on the surface of the oxide. The metal element includes at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir. The oxide includes one or two of Ov-ZnO, Ov-TiO2, Ov-CeO2, Ov-Fe2O3, Ov-SnO2, Ov-Al2O3, Ov-CuO, Ov-Cu2O, Ov-Cr2O3, Ov-MnO, and Ov-V2O5.

2. The method according to claim 1, characterized in that, The biomass-based compounds include furan benzyl chloride, ethyl ester-substituted benzyl chloride, amide-substituted benzyl chloride, furan benzyl bromide, or methyl p-chloromethylbenzoate.

3. The method according to claim 1 or 2, characterized in that, The solvent in the biomass-based compound solution includes one or more of isopropanol, water, 3-pentanol, 2,4-dimethyl-3-pentanol, tetrahydrofuran, acetonitrile, and dimethylformamide.

4. The method according to claim 3, characterized in that, The solvent in the biomass-based compound solution is selected from a mixture of isopropanol and water, a mixture of 3-pentanol and water, or a mixture of 2,4-dimethyl-3-pentanol and water.

5. The method according to claim 1 or 2, characterized in that, The reducing agent includes one or more of isopropanol, methanol, cyclohexanol, ethanol, benzyl alcohol, and furfuryl alcohol.

6. The method according to claim 1 or 2, characterized in that, The protective gas atmosphere is a 1-3 bar argon atmosphere, and / or the light source is a 365 nm ultraviolet lamp or 365 nm simulated sunlight.

7. The method according to claim 1 or 2, characterized in that, The metal / oxide photocatalyst material is a Cu-Au / Ov-ZnO heterojunction photocatalyst, and the preparation method of the Cu-Au / Ov-ZnO heterojunction photocatalyst includes the following steps: Oxygen vacancies were constructed in ZnO nanoparticles by chemical reduction to obtain Ov-ZnO; Au-Cu bimetallic nanoparticles were loaded onto the surface of Ov-ZnO by photodeposition and dried to obtain a Cu-Au / Ov-ZnO heterojunction photocatalyst. In the Cu-Au / Ov-ZnO heterojunction photocatalyst, the loading of Au in Ov-ZnO is 2~3wt%, and the loading of Cu in Ov-ZnO is 1~3wt%.

8. The method according to claim 7, characterized in that, The specific preparation method of the Ov-ZnO is as follows: ZnO nanoparticles were dispersed in water and subjected to ultrasonic treatment to obtain a suspension; Under anhydrous and oxygen-free conditions, NaBH4 aqueous solution was added to the suspension for reduction while it was being stirred to obtain Ov-ZnO; The specific steps for obtaining the Cu-Au / Ov-ZnO heterojunction photocatalyst are as follows: Ov-ZnO was dispersed in a solvent, and then copper source solution and gold source solution were added. The mixture was irradiated with 365nm light for 1-3 hours under anhydrous and oxygen-free conditions to obtain Cu-Au / Ov-ZnO heterojunction photocatalyst.

9. The method according to claim 8, characterized in that, The specific surface area of ​​the Cu-Au / Ov-ZnO heterojunction photocatalyst is not less than 16.5 m². 2 / g.

10. A metal / oxide composite material comprising an oxide and a metal element supported on the surface of the oxide, wherein the metal element comprises at least two of Cu, Au, Pd, Ag, Fe, Co, Ni, Pt, Rh, and Ir, and the oxide comprises one or two of Ov-ZnO, Ov-TiO2, Ov-CeO2, Ov-Fe2O3, Ov-SnO2, Ov-Al2O3, Ov-CuO, Ov-Cu2O, Ov-Cr2O3, Ov-MnO, and Ov-V2O5.

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