WO2022268021A1 - Cu-based catalyst and use thereof for photocatalytic water-based hydrogen production-5-hydroxymethylfurfural (hmf) oxidation coupling reaction - Google Patents

Cu-based catalyst and use thereof for photocatalytic water-based hydrogen production-5-hydroxymethylfurfural (hmf) oxidation coupling reaction Download PDF

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WO2022268021A1
WO2022268021A1 PCT/CN2022/099795 CN2022099795W WO2022268021A1 WO 2022268021 A1 WO2022268021 A1 WO 2022268021A1 CN 2022099795 W CN2022099795 W CN 2022099795W WO 2022268021 A1 WO2022268021 A1 WO 2022268021A1
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catalyst
hmf
hydrogen production
coalo
reaction
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冯俊婷
王红燕
王倩
李殿卿
贺宇飞
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北京化工大学
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/75—Cobalt
    • B01J35/396—
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    • B01J35/50—
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
    • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
    • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
    • C07D307/56—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D307/68—Carbon atoms having three bonds to hetero atoms with at the most one bond to halogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/133—Renewable energy sources, e.g. sunlight

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  • the invention relates to the technical field of catalysis, in particular to a Cu-based catalyst and its use in photocatalytic water hydrogen production-5-HMF oxidative coupling reaction to obtain high value-added chemicals while improving hydrogen production performance.
  • Photocatalytic hydrogen production technology can utilize abundant and clean solar energy, and has the characteristics of environmental friendliness and low energy consumption. Therefore, it is a hydrogen energy production method with broad application prospects.
  • photoexcited electrons reduce protons to generate H 2 , but the oxidation ability of excited holes is not fully utilized.
  • FDCA 2,5-furandicarboxylic acid
  • PEF polyethylene furanate
  • Literature 3Feng et al. synthesized CuMgAl-LDH, CuCoAl- LDH and other precursors, and the LDH precursor was reduced in 10% H 2 /Ar atmosphere at 300°C for 4 hours at high temperature to prepare a Cu-based catalyst for the hydrogenation reaction of 5-hydroxymethylfurfural.
  • our idea of invention is: using LDHs as a platform, based on its topological effect and compositional adjustability, introduce photosensitive ions such as Cu 2+ into hydrotalcite laminates, design and synthesize a kind of photoresponsive ability, high activity and suitable for It is a photocatalyst for the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, and realizes the enhancement of catalytic performance under the condition of no external base.
  • the purpose of the present invention is to provide a Cu-based catalyst, which is specially used for the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction.
  • the Cu-based catalyst of the present invention has a chemical expression of Cu/CoAlO, wherein the molar ratio of Cu to Co is 1:3 to 1:5, and the molar ratio of Co to Al is 1.5 to 2.5;
  • the structural characteristics of the catalyst It is Cu and Co species that form metal nanoparticles with a Co@CuCo core-shell structure on the surface of the carrier, and the metal particles are uniformly distributed, and the average particle size of the metal particles is 2-10 nm;
  • the Cu/CoAlO catalyst is specially used for photocatalytic water hydrogen production-5-HMF oxidative coupling reaction. Under the condition of no external alkali, the highest hydrogen production rate can reach 796.8 ⁇ 888.3 ⁇ molh -1 g -1 after 6 hours of reaction, FDCA selectivity It can reach 93.7-95.5%, much higher than the performance reported in the literature. It shows that the catalyst not only promotes the improvement of hydrogen production efficiency, but also realizes the efficient and directional conversion of 5-HMF to FDCA under neutral conditions.
  • the above-mentioned Cu/CoAlO catalyst is obtained by calcining hydrotalcite containing Cu 2+ , Co 2+ and Al 3+ metal ions at a high temperature of 550-650°C in a mixed atmosphere of H 2 /N 2 or H 2 /Ar of.
  • the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction pathway is as follows:
  • the Cu-based catalyst used has suitable valence and conduction band positions, its conduction band position meets the thermodynamic requirements for reducing H protons to hydrogen, and the valence band position not only meets the VB value required for oxygen production, but also reaches the 5-HMF VB value required for oxidation. Therefore, under the condition of no external base, the excited holes oxidize 5-HMF to DFF, and at the same time oxidize water to generate O 2 , and the oxygen generated by water oxidation further rapidly oxidizes DFF to FDCA.
  • Fig. 1 is the HRTEM photo and particle size distribution diagram of the Cu/CoAlO catalyst whose Cu/Co molar ratio is 1/5 prepared in Example 1, as can be seen from the figure, the metal particles are evenly distributed on the carrier, and the nanoparticle size range It is 2.0-10.0nm, and the average particle size is 5.8nm.
  • Fig. 2 is the X-ray energy spectrum (EDS) line scan result of metal Co and Cu in the Cu/CoAlO catalyst in the Cu/CoAlO catalyst of 1/5 that Cu/Co molar ratio prepared in embodiment 1, contrasts the distribution of element Co and Cu It can be seen that Co is distributed throughout the metal particles and Cu is concentrated on the surface of the metal particles, so it can be concluded that the catalyst active component metal nanoparticles present a core-shell structure of Co@CuCo.
  • EDS X-ray energy spectrum
  • Fig. 3 is the XPS valence band spectrogram and the Tauc figure of the Cu/CoAlO catalyst of 1/5 for the Cu/Co molar ratio prepared in embodiment 1, can find out the valence band (VB) of catalyst by figure (a) valence band spectrogram ) value is 1.73eV, and the energy bandgap (Eg) of the catalyst can be drawn as 2.67eV from Figure (b) Tauc diagram.
  • Fig. 4 is the energy band structure diagram of the Cu/CoAlO catalyst that the Cu/Co molar ratio prepared in Example 1 is 1/5, as can be seen from the figure, the CB value of the catalyst is lower than the reduction potential (0eV) of the H proton, at Under the irradiation of a light source with an appropriate wavelength, the thermodynamic requirements for reducing H protons to hydrogen can be met.
  • CuCo/Al 2 O 3 has a suitable valence band position, it not only meets the VB value (1.23eV) required for oxygen generation, but also achieves the VB value (0.82eV) required for 5-HMF oxidation. Therefore, holes can not only oxidize 5-HMF to DFF, but also oxidize water to generate O 2 , and the oxygen produced by water oxidation can further rapidly oxidize DFF to FDCA.
  • Figure 5 is a line graph of the hydrogen production over time in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction of the Cu/CoAlO catalyst with a Cu/Co molar ratio of 1/5 prepared in Example 1, within 6h , the amount of hydrogen produced by the catalyst tended to increase with the prolongation of the reaction time, the highest hydrogen production rate reached 888.3 ⁇ molh -1 g -1 , and the hydrogen production after 6h was 9.78 ⁇ mol.
  • Fig. 6 is the HPLC spectrogram of the reaction solution in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction of the Cu/CoAlO catalyst with a Cu/Co molar ratio of 1/5 prepared in Example 1, as can be seen from the figure, The peak position of 5-HMF was 2.8 min, and the peak position of 2,5-furandicarboxylic acid (FDCA) was 2 min. Only FDCA, 5-HMF and a small amount of DFF were detected in the liquid phase product after 6 hours of reaction. No other products were detected, indicating that the coupling reaction is highly selective for FDCA.
  • Fig. 7 is that the Cu/Co molar ratio prepared in Example 1 is the concentration curve of the product FDCA of 1/5 Cu/CoAlO catalyst in photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, 5-HMF Conversion and FDCA selectivity curves. When reacted for 6h, the conversion rate of 5-HMF was 11.2%, and the selectivity of FDCA was 95.5%.
  • the beneficial effects of the present invention are: the application of the supported Cu-based catalyst obtained based on the topological reduction of LDHs precursors in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction is discovered for the first time, which can not only promote the improvement of hydrogen production efficiency, but also It can realize high-efficiency directional conversion from 5-HMF to FDCA under neutral conditions.
  • the Cu-based catalyst has outstanding catalytic performance, simple preparation and environmental friendliness.
  • Figure 1 is the HRTEM photo and particle size distribution diagram of the catalyst prepared in Example 1, wherein Figure a is the HRTEM photo of the catalyst, and Figure b is the size distribution diagram of the metal nanoparticles.
  • Fig. 2 is the line-scan spectrogram of metal particle X-ray Co and Cu of the catalyst prepared in Example 1.
  • Figure 3 is the XPS valence band spectrum and Tauc diagram of the catalyst prepared in Example 1, wherein Figure a is the valence band spectrum and Figure b is the Tauc diagram.
  • Figure 4 is a diagram of the energy band structure of the catalyst prepared in Example 1.
  • Fig. 5 is a line graph showing the change of the amount of hydrogen produced by the catalyst prepared in Example 1 in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction with time.
  • Figure 6 is the HPLC spectrogram of the reaction solution in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction of the catalyst prepared in Example 1, wherein Figure a is the HPLC spectrum before the reaction, and Figure b is the HPLC spectrum after the reaction for 6h picture.
  • Fig. 7 is the time-varying curve of the concentration of FDCA, the conversion rate of 5-HMF and the FDCA selectivity curve of the catalyst prepared in Example 1 in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction.
  • figure a is the concentration curve of the product FDCA with time
  • figure b is the conversion rate of 5-HMF and the selectivity curve of FDCA.
  • the furnace temperature is naturally cooled to room temperature to obtain a Cu/CoAlO catalyst, wherein the Cu/Co molar ratio is 1/5, and the mass percentages of Cu, Co and Al elements are 8.3%, 42.7% respectively and 7.8%.
  • the obtained samples were characterized, and the results are shown in Fig. 1-Fig. 4. It can be seen from the characterization results that the catalyst metal nanoparticles present a core-shell structure of Co@CuCo alloy, and the metal nanoparticles are uniformly dispersed in the amorphous Al 2 O 3 on the carrier, the average size of nanoparticles is 5.8nm.
  • the valence band (VB) value of the catalyst is 1.73eV
  • the conduction band (CB) value is -0.94eV.
  • the conduction band value meets the thermodynamic requirements for reducing H protons to hydrogen
  • the valence band value meets the VB value required for oxygen production. (1.23eV)
  • the VB value (0.82eV) required for the oxidation of 5-HMF.
  • the catalyst obtained above is used in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction.
  • the specific method is: in a sealable reactor with a volume of 20mL, first add 5mg of catalyst and 13mg of 5-hydroxymethylfurfural, Then add 10mL of pure water and seal it with a capper. Under magnetic stirring, replace the air in the reaction bottle with high-purity Ar for 30 minutes, then turn on the 300W Xe lamp (>380nm), keep the distance between the lamp and the reaction bottle about 5cm, and the lamp current intensity is 16A, irradiate the reaction solution, and the magnetic stirring speed is set to It is 600rpm, and the reaction time is 6h.
  • the Cu/CoAlO catalyst is prepared according to the method of Example 1, the difference is that the metal molar ratio of Cu, Co and Al in the mixed salt solution is 1:4:2, and the mass percentage of Cu, Co and Al elements in the obtained catalyst 9.6%, 37.6% and 8.5% respectively.
  • the obtained catalyst was used in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, the results are shown in Table 1, and it can be seen from Table 1 that after 6 hours of reaction, the catalyst was under the condition of no additional alkali
  • the selectivity of FDCA is 94.3%
  • the hydrogen production amount after 6h is 8.03 ⁇ mol
  • the highest hydrogen production rate can reach 798.0 ⁇ molh -1 g -1 .
  • the Cu/CoAlO catalyst was prepared according to the method of Example 1, except that the metal molar ratio of Cu, Co and Al in the mixed salt solution was 1:3:2, and the calcination reduction temperature was 550°C; the obtained catalyst contained Cu, Co
  • the mass percent contents of Al and Al elements are 10.8%, 33.7% and 10.4%, respectively.
  • the obtained catalyst was used in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, the results are shown in Table 1, and it can be seen from Table 1 that after 6 hours of reaction, the catalyst was under the condition of no additional alkali
  • the selectivity of FDCA is 94.5%
  • the hydrogen production amount after 6h is 7.4 ⁇ mol
  • the highest hydrogen production rate can reach 796.8 ⁇ molh -1 g -1 .
  • Comparative Example 1 and Comparative Example 2 are the literature values of the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction.
  • Comparative example 1 is the hydrogen production of the Ni/CdS NSs catalyst in Document 1 after 6 hours of reaction, and the DFF selectivity after 22 hours of reaction, but the catalyst will quickly convert DFF to FDCA after adding a strong base to the reaction system.
  • Comparative Example 2 is the performance of the Zn x Cd 1-x SP catalyst in Document 2 after 8 hours of reaction.
  • the catalyst of the present invention has higher selectivity for 2,5-furandicarboxylic acid (FDCA) under the condition of no external base, which is higher than that of the comparative example, and the 5-hydroxymethyl Efficient and targeted conversion of furfural (5-HMF) to 2,5-furandicarboxylic acid (FDCA).

Abstract

The present invention provides a Cu-based catalyst and a use thereof for photocatalytic water-based hydrogen production-5-hydroxymethylfurfural (HMF) oxidation coupling reaction. The chemical expression of the Cu-based catalyst is Cu/CoAlO, the catalyst is obtained by using hydrotalcite having Cu2+, Co2+, and Al3+ as metal cations as a precursor, and roasting at a high temperature of 550-650°C under a mixed atmosphere of H2/N2 or H2/Ar, Cu and Co species form metal nanoparticles having a Co@CuCo core-shell structure on the surface of a carrier, the metal particles are evenly distributed, and the metal particles have an average particle size of 2-10 nm; the catalyst has a valence band (VB) value of 1.7-2.0 eV, and a conduction band (CB) value of -0.8--1.0 eV. The catalyst is applied to a photocatalytic water-based hydrogen production-5-HMF oxidation coupling reaction without additional alkali. Thus, hydrogen production efficiency is improved, efficient directional conversion from 5-HMF to 2,5-furandicarboxylic acid under a neutral condition is also achieved. The Cu-based catalyst has outstanding catalytic performance, is simple to prepare, and is environmentally friendly.

Description

一种Cu基催化剂及将其用于光催化水产氢-5-HMF氧化偶联反应A Cu-based catalyst and its use in photocatalytic water hydrogen production-5-HMF oxidative coupling reaction 技术领域technical field
本发明涉及催化技术领域，具体涉及一种Cu基催化剂及将其用于光催化水产氢-5-HMF氧化偶联反应中，在提高产氢性能的同时得到高附加值的化学品。The invention relates to the technical field of catalysis, in particular to a Cu-based catalyst and its use in photocatalytic water hydrogen production-5-HMF oxidative coupling reaction to obtain high value-added chemicals while improving hydrogen production performance.
背景技术Background technique
随着经济的快速发展和人民生活水平的不断提高，对能源的需求持续增长。开发清洁、无污染，可再生，高能量密度的氢能对于解决当前的能源和环境问题至关重要。光催化产氢技术能够利用丰富且清洁的太阳能，具有环境友好且能耗低的特点，因此，是一种具有广阔应用前景的氢能生产方式。在传统的光催化水分解产氢反应中，光激发电子还原质子产生H 2，但激发空穴的氧化能力没有得到充分利用。因此，若利用来源丰富且容易获得的原料(例如5-HMF及其衍生物)来捕获激发空穴，将光催化水产氢反应与5-HMF氧化反应偶联，在促进产氢效率提升的同时，获得高附加值的下游产品，不仅可以有效促进太阳能利用效率，还能实现可再生资源的高值转化。近年来，为缓解当前的能源危机，将可再生5-HMF资源转化为增值化学品引起了越来越多的关注。通过C 6碳水化合物脱水生产的5-羟甲基糠醛(5-HMF)被美国能源部列为12大可持续5-HMF增值化学品之一，其下游产品2,5-呋喃二甲酸(FDCA)被认为是合成聚合物，特别是聚呋喃甲酸乙二醇酯(PEF)的重要单体替代品，PEF被认为是聚合物聚对苯二甲酸乙二醇酯的一种有潜力的替代品。 With the rapid development of the economy and the continuous improvement of people's living standards, the demand for energy continues to grow. The development of clean, non-polluting, renewable, and high-energy-density hydrogen energy is crucial to solving current energy and environmental issues. Photocatalytic hydrogen production technology can utilize abundant and clean solar energy, and has the characteristics of environmental friendliness and low energy consumption. Therefore, it is a hydrogen energy production method with broad application prospects. In the traditional photocatalytic water splitting hydrogen production reaction, photoexcited electrons reduce protons to generate H 2 , but the oxidation ability of excited holes is not fully utilized. Therefore, if abundant and easily available raw materials (such as 5-HMF and its derivatives) are used to capture the excited holes and couple the photocatalytic water hydrogen production reaction with the 5-HMF oxidation reaction, while promoting the hydrogen production efficiency , to obtain high-value-added downstream products, which can not only effectively promote solar energy utilization efficiency, but also realize high-value conversion of renewable resources. In recent years, to alleviate the current energy crisis, the conversion of renewable 5-HMF resources into value-added chemicals has attracted increasing attention. 5 -Hydroxymethylfurfural (5-HMF) produced by dehydration of C carbohydrates is listed as one of the 12 sustainable 5-HMF value-added chemicals by the U.S. Department of Energy, and its downstream product 2,5-furandicarboxylic acid (FDCA ) is considered an important monomer substitute for synthetic polymers, especially polyethylene furanate (PEF), which is considered a potential substitute for the polymer polyethylene terephthalate .
文献1在Visible-Light-Driven Valorization of Biomass Intermediates Integrated with H 2Production Catalyzed by Ultrathin Ni/CdS Nanosheets.Journal of the American Chemical Society,2017,139(44):15584-15587中，Sun等首次报道了以负载镍的硫化镉纳米片(Ni/CdS NSs)为光催化剂可以实现可见光下同时析氢和5-HMF衍生醇的选择性氧化，在反应22h后，5-羟甲基糠醛(5-HMF)的转化的产物中，2,5-二甲酰基呋喃(DFF)的选择性接近100％，在体系中加入强碱后，由于醛基的不稳定，DFF会快速转化为FDCA。但是，由于CdS的导带位置较低，因此析氢速率较低。 Document 1 In Visible-Light-Driven Valorization of Biomass Intermediates Integrated with H 2 Production Catalyzed by Ultrathin Ni/CdS Nanosheets.Journal of the American Chemical Society, 2017,139(44):15584-15587, Sun et al. reported for the first time that Ni-supported cadmium sulfide nanosheets (Ni/CdS NSs) as photocatalysts can realize simultaneous hydrogen evolution and selective oxidation of 5-HMF-derived alcohols under visible light. Among the converted products, the selectivity of 2,5-diformylfuran (DFF) is close to 100%. After adding a strong base to the system, DFF will be rapidly converted to FDCA due to the instability of the aldehyde group. However, due to the lower conduction band position of CdS, the hydrogen evolution rate is lower.
文献2Chen等在P-doped Zn xCd 1-xS solid solutions as photocatalysts for hydrogen evolution from water splitting coupled with photocatalytic oxidation of 5-hydroxymethylfurfural.Applied Catalysis B:Environmental 233(2018)70–79中,制备了具有富S空位的P掺杂Zn xCd 1-xS(Zn xCd 1-xS-P)作为光催化剂，同时用于分解水制氢和光催化氧化5-HMF。反应8h后,5-羟甲基糠醛转化的产物中，DFF的选择性为65％，最高产氢速率为786μmol·g -1·h -1。 Literature 2Chen et al. in P-doped Zn x Cd 1-x S solid solutions as photocatalysts for hydrogen evolution from water splitting coupled with photocatalytic oxidation of 5-hydroxymethylfurfural. Applied Catalysis B: Environmental 233 (2018) 70-79, prepared a compound with S-vacancy-rich P-doped Zn x Cd 1-x S (Zn x Cd 1-x SP) was used as a photocatalyst for hydrogen production from water splitting and photocatalytic oxidation of 5-HMF. After 8 hours of reaction, the selectivity of DFF was 65% among the converted products of 5-hydroxymethylfurfural, and the highest hydrogen production rate was 786μmol·g -1 ·h -1 .
在光催化水产氢-5-羟甲基糠醛氧化偶联反应已发表的文献报道中，可以发现，在中性条件下，5-HMF的氧化产物基本都是2,5-二甲酰基呋喃(DFF)。只有在强碱性条件下，由于醛 基在高pH条件下不稳定，会快速转化为2,5-呋喃二甲酸(FDCA)。虽然向反应体系中加入碱性溶液能够提高对FDCA的选择性，但是不符合绿色化学的发展趋势且易造成设备的腐蚀。因此，设计合成非强碱性条件下在偶联反应中，对FDCA有高选择性的环境友好型光催化剂具有重要的意义。In the published literature reports on photocatalytic water hydrogenation-5-hydroxymethylfurfural oxidative coupling reaction, it can be found that under neutral conditions, the oxidation products of 5-HMF are basically 2,5-diformylfuran ( DFF). Only under strongly alkaline conditions, due to the instability of the aldehyde group at high pH, is it rapidly converted to 2,5-furandicarboxylic acid (FDCA). Although adding alkaline solution to the reaction system can improve the selectivity to FDCA, it does not conform to the development trend of green chemistry and easily causes corrosion of equipment. Therefore, it is of great significance to design and synthesize environmentally friendly photocatalysts with high selectivity for FDCA in coupling reactions under non-strongly alkaline conditions.
文献3Feng等在Interfacial Structure-Determined Reaction Pathway and Selectivity for 5-(Hydroxymethyl)furfural Hydrogenation over Cu-Based Catalysts.ACS Catal.2020,10,1353-1365中，利用共沉淀法合成了CuMgAl-LDH，CuCoAl-LDH等前驱体，并将LDH前体在10％H 2/Ar气氛下于300℃高温还原4h，以制备用于5-羟甲基糠醛加氢反应的Cu基催化剂。 Literature 3Feng et al. synthesized CuMgAl-LDH, CuCoAl- LDH and other precursors, and the LDH precursor was reduced in 10% H 2 /Ar atmosphere at 300°C for 4 hours at high temperature to prepare a Cu-based catalyst for the hydrogenation reaction of 5-hydroxymethylfurfural.
文献4Zhao等在Layered Double Hydroxide Nanostructured Photocatalysts for Renewable Energy Production.Advanced Energy Materials,2016,6(6):1501974中阐释，层状双金属氢氧化物(LDHs)作为典型的二维层状材料，由于其优异的电子性能和光生电子-空穴对快速传输的能力使其在光催化领域展现出巨大的应用前景。基于其组成可调性，在层板中引入特定的光敏金属离子，可以调控其能带结构。偶联反应在光催化产氢领域有很大的发展前景，而在这个新兴领域中，以LDH制备光催化材料还很少有人报道。因此，LDH为开发具有高活性的适于光催化偶联反应的光催化剂提供了一个强大的结构平台。 Literature 4 Zhao et al. explained in Layered Double Hydroxide Nanostructured Photocatalysts for Renewable Energy Production. Advanced Energy Materials, 2016, 6(6): 1501974 that layered double metal hydroxides (LDHs) as a typical two-dimensional layered material, due to its The excellent electronic properties and the ability of fast transport of photogenerated electron-hole pairs make them show great application prospects in the field of photocatalysis. Based on its compositional tunability, introducing specific photosensitive metal ions into the laminate can tune its energy band structure. The coupling reaction has great development prospects in the field of photocatalytic hydrogen production, but in this emerging field, the preparation of photocatalytic materials from LDH has been rarely reported. Therefore, LDHs provide a powerful structural platform for the development of highly active photocatalysts suitable for photocatalytic coupling reactions.
因此，我们的发明思路是：以LDHs为平台，基于其拓扑效应和组成可调性，将光敏离子Cu 2+等引入水滑石层板，设计合成一种光响应能力强、高活性且适于光催化水产氢-5-HMF氧化偶联反应的光催化剂，并在无外加碱条件下实现催化性能的强化。 Therefore, our idea of invention is: using LDHs as a platform, based on its topological effect and compositional adjustability, introduce photosensitive ions such as Cu 2+ into hydrotalcite laminates, design and synthesize a kind of photoresponsive ability, high activity and suitable for It is a photocatalyst for the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, and realizes the enhancement of catalytic performance under the condition of no external base.
发明内容Contents of the invention
本发明的目的是提供一种Cu基催化剂，该催化剂专用于光催化水产氢-5-HMF氧化偶联反应。The purpose of the present invention is to provide a Cu-based catalyst, which is specially used for the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction.
本发明所述的Cu基催化剂，其化学表示式为Cu/CoAlO，其中Cu与Co的摩尔比为1:3～1:5，Co和Al的摩尔比为1.5～2.5；该催化剂的结构特点是Cu和Co物种在载体表面形成具有Co@CuCo核壳结构的金属纳米颗粒且金属颗粒均匀分布，金属颗粒平均粒径为2～10nm；该催化剂的价带值VB＝1.7～2.0eV，导带值CB为-0.8～-1.0eV。The Cu-based catalyst of the present invention has a chemical expression of Cu/CoAlO, wherein the molar ratio of Cu to Co is 1:3 to 1:5, and the molar ratio of Co to Al is 1.5 to 2.5; the structural characteristics of the catalyst It is Cu and Co species that form metal nanoparticles with a Co@CuCo core-shell structure on the surface of the carrier, and the metal particles are uniformly distributed, and the average particle size of the metal particles is 2-10 nm; the valence band value of the catalyst is VB=1.7-2.0 eV, leading The band value CB is -0.8 to -1.0 eV.
该Cu/CoAlO催化剂专用于光催化水产氢-5-HMF氧化偶联反应，在无外加碱的条件下，反应6h后最高产氢速率可达796.8～888.3μmolh -1g -1，FDCA选择性可达93.7～95.5％，远高于文献报道的性能。说明该催化剂在促进产氢效率提升的同时，还实现了在中性条件下由5-HMF向FDCA的高效定向转化。 The Cu/CoAlO catalyst is specially used for photocatalytic water hydrogen production-5-HMF oxidative coupling reaction. Under the condition of no external alkali, the highest hydrogen production rate can reach 796.8～888.3μmolh -1 g -1 after 6 hours of reaction, FDCA selectivity It can reach 93.7-95.5%, much higher than the performance reported in the literature. It shows that the catalyst not only promotes the improvement of hydrogen production efficiency, but also realizes the efficient and directional conversion of 5-HMF to FDCA under neutral conditions.
上述Cu/CoAlO催化剂是由含Cu 2+、Co 2+和Al 3+金属离子的水滑石作为前驱体，在H 2/N 2或H 2/Ar的混合气氛下550～650℃高温焙烧得到的。 The above-mentioned Cu/CoAlO catalyst is obtained by calcining hydrotalcite containing Cu 2+ , Co 2+ and Al 3+ metal ions at a high temperature of 550-650°C in a mixed atmosphere of H 2 /N 2 or H 2 /Ar of.
Cu/CoAlO催化剂具体应用步骤如下：The specific application steps of Cu/CoAlO catalyst are as follows:
向可密封的反应器中加入反应物5-HMF、Cu/CoAlO和去离子水，其中5-HMF和Cu/CoAlO的质量比为2～6，5-HMF的质量浓度为1.0～3.3g/L；在磁力搅拌下，用高纯Ar充分置换反应瓶中的空气，用300W Xe灯(λ>380nm)，照射反应液，在充分搅拌下反应1～8h，得到FDCA产品。Add reactant 5-HMF, Cu/CoAlO and deionized water in the sealable reactor, wherein the mass ratio of 5-HMF and Cu/CoAlO is 2～6, the mass concentration of 5-HMF is 1.0～3.3g/ L: Under magnetic stirring, fully replace the air in the reaction bottle with high-purity Ar, irradiate the reaction solution with a 300W Xe lamp (λ>380nm), and react for 1 to 8 hours under sufficient stirring to obtain the FDCA product.
光催化水产氢-5-HMF氧化偶联反应路径如下：The photocatalytic water hydrogen production-5-HMF oxidative coupling reaction pathway is as follows:
Figure PCTCN2022099795-appb-000001
Figure PCTCN2022099795-appb-000001
由于所用的Cu基催化剂具有合适的价带和导带位置，其导带位置满足将H质子还原为氢气的热力学要求，价带位置既满足产氧所需的VB值，也达到了5-HMF氧化所需的VB值。因此，在无外加碱的条件下，激发空穴将5-HMF氧化为DFF，同时将水氧化产生O 2，水氧化产生的氧气进一步将DFF快速氧化为FDCA。 Since the Cu-based catalyst used has suitable valence and conduction band positions, its conduction band position meets the thermodynamic requirements for reducing H protons to hydrogen, and the valence band position not only meets the VB value required for oxygen production, but also reaches the 5-HMF VB value required for oxidation. Therefore, under the condition of no external base, the excited holes oxidize 5-HMF to DFF, and at the same time oxidize water to generate O 2 , and the oxygen generated by water oxidation further rapidly oxidizes DFF to FDCA.
图1为实施例1制备的Cu/Co摩尔比为1/5的Cu/CoAlO催化剂的HRTEM照片和颗粒尺寸分布图，从图中可以看出，金属颗粒均匀地分布在载体，纳米颗粒尺寸范围为2.0～10.0nm，颗粒平均尺寸为5.8nm。Fig. 1 is the HRTEM photo and particle size distribution diagram of the Cu/CoAlO catalyst whose Cu/Co molar ratio is 1/5 prepared in Example 1, as can be seen from the figure, the metal particles are evenly distributed on the carrier, and the nanoparticle size range It is 2.0-10.0nm, and the average particle size is 5.8nm.
图2为实施例1制备的Cu/Co摩尔比为1/5的Cu/CoAlO催化剂中金属颗粒的X-射线能谱(EDS)金属Co和Cu的线扫结果，对比元素Co和Cu的分布可以看出，Co分布于整个金属颗粒而Cu集中分布在金属颗粒表面，因此可以判定该催化剂活性组分金属纳米颗粒呈现出Co@CuCo的核壳结构。Fig. 2 is the X-ray energy spectrum (EDS) line scan result of metal Co and Cu in the Cu/CoAlO catalyst in the Cu/CoAlO catalyst of 1/5 that Cu/Co molar ratio prepared in embodiment 1, contrasts the distribution of element Co and Cu It can be seen that Co is distributed throughout the metal particles and Cu is concentrated on the surface of the metal particles, so it can be concluded that the catalyst active component metal nanoparticles present a core-shell structure of Co@CuCo.
图3为实施例1制备的Cu/Co摩尔比为1/5的Cu/CoAlO催化剂的XPS价带谱图和Tauc图，由图(a)价带谱图可以看出催化剂的价带(VB)值为1.73eV，由图(b)Tauc图可以得出催化剂的能带间隙(Eg)为2.67eV。Fig. 3 is the XPS valence band spectrogram and the Tauc figure of the Cu/CoAlO catalyst of 1/5 for the Cu/Co molar ratio prepared in embodiment 1, can find out the valence band (VB) of catalyst by figure (a) valence band spectrogram ) value is 1.73eV, and the energy bandgap (Eg) of the catalyst can be drawn as 2.67eV from Figure (b) Tauc diagram.
图4为实施例1制备的Cu/Co摩尔比为1/5的Cu/CoAlO催化剂的能带结构图，从图中可以看出催化剂的CB值低于H质子的还原电位(0eV)，在适当波长的光源照射下，均可以满足将H质子还原为氢气的热力学要求。此外，由于CuCo/Al 2O 3具有合适的价带位置，既满足产氧所需的VB值(1.23eV)，也达到了5-HMF氧化所需的VB值(0.82eV)。因此，空穴既可以将5-HMF氧化为DFF，也可以氧化水以产生O 2，随后水氧化产生的氧气也可以进一步将DFF快速氧化为FDCA。 Fig. 4 is the energy band structure diagram of the Cu/CoAlO catalyst that the Cu/Co molar ratio prepared in Example 1 is 1/5, as can be seen from the figure, the CB value of the catalyst is lower than the reduction potential (0eV) of the H proton, at Under the irradiation of a light source with an appropriate wavelength, the thermodynamic requirements for reducing H protons to hydrogen can be met. In addition, because CuCo/Al 2 O 3 has a suitable valence band position, it not only meets the VB value (1.23eV) required for oxygen generation, but also achieves the VB value (0.82eV) required for 5-HMF oxidation. Therefore, holes can not only oxidize 5-HMF to DFF, but also oxidize water to generate O 2 , and the oxygen produced by water oxidation can further rapidly oxidize DFF to FDCA.
图5为实施例1制备的Cu/Co摩尔比为1/5的Cu/CoAlO催化剂在光催化水产氢-5-HMF氧化偶联反应中的产氢量随时间的变化折线图，在6h内，催化剂的产氢量随反应时间的延长呈递增的趋势，最高产氢速率可达888.3μmolh -1g -1，6h后的产氢量为9.78μmol。 Figure 5 is a line graph of the hydrogen production over time in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction of the Cu/CoAlO catalyst with a Cu/Co molar ratio of 1/5 prepared in Example 1, within 6h , the amount of hydrogen produced by the catalyst tended to increase with the prolongation of the reaction time, the highest hydrogen production rate reached 888.3μmolh -1 g -1 , and the hydrogen production after 6h was 9.78μmol.
图6为实施例1制备的Cu/Co摩尔比为1/5的Cu/CoAlO催化剂在光催化水产氢-5-HMF 氧化偶联反应中反应液的HPLC谱图，从图中可以看出，5-HMF的出峰位置为2.8min，2,5-呋喃二甲酸(FDCA)的出峰位置为2min，在反应6h后的液相产物中仅检测到FDCA、5-HMF和微量的DFF，未检测到其他产物，说明偶联反应对于FDCA具有很高的选择性。Fig. 6 is the HPLC spectrogram of the reaction solution in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction of the Cu/CoAlO catalyst with a Cu/Co molar ratio of 1/5 prepared in Example 1, as can be seen from the figure, The peak position of 5-HMF was 2.8 min, and the peak position of 2,5-furandicarboxylic acid (FDCA) was 2 min. Only FDCA, 5-HMF and a small amount of DFF were detected in the liquid phase product after 6 hours of reaction. No other products were detected, indicating that the coupling reaction is highly selective for FDCA.
图7为实施例1制备的Cu/Co摩尔比为1/5的Cu/CoAlO催化剂在光催化水产氢-5-HMF氧化偶联反应中的产物FDCA的浓度随时间变化曲线，5-HMF的转化率和FDCA选择性曲线。当反应6h时，5-HMF的转化率为11.2％，FDCA选择性为95.5％。Fig. 7 is that the Cu/Co molar ratio prepared in Example 1 is the concentration curve of the product FDCA of 1/5 Cu/CoAlO catalyst in photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, 5-HMF Conversion and FDCA selectivity curves. When reacted for 6h, the conversion rate of 5-HMF was 11.2%, and the selectivity of FDCA was 95.5%.
本发明的有益效果是：首次发现了基于LDHs前驱体拓扑还原得到的负载型Cu基催化剂在光催化水产氢-5-HMF氧化偶联反应中的应用，不仅可以促进产氢效率的提升，还能实现中性条件下由5-HMF向FDCA的高效定向转化。该Cu基催化剂催化性能突出、制备简单且环境友好。The beneficial effects of the present invention are: the application of the supported Cu-based catalyst obtained based on the topological reduction of LDHs precursors in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction is discovered for the first time, which can not only promote the improvement of hydrogen production efficiency, but also It can realize high-efficiency directional conversion from 5-HMF to FDCA under neutral conditions. The Cu-based catalyst has outstanding catalytic performance, simple preparation and environmental friendliness.
附图说明：Description of drawings:
图1为实施例1制备的催化剂的HRTEM照片和颗粒尺寸分布图，其中图a为催化剂的HRTEM照片，图b为金属纳米颗粒的尺寸分布图。Figure 1 is the HRTEM photo and particle size distribution diagram of the catalyst prepared in Example 1, wherein Figure a is the HRTEM photo of the catalyst, and Figure b is the size distribution diagram of the metal nanoparticles.
图2为实施例1制备的催化剂的金属颗粒X-射线Co和Cu的线扫谱图。Fig. 2 is the line-scan spectrogram of metal particle X-ray Co and Cu of the catalyst prepared in Example 1.
图3为实施例1制备的催化剂的XPS价带谱图和Tauc图，其中图a为价带谱图，图b为Tauc图。Figure 3 is the XPS valence band spectrum and Tauc diagram of the catalyst prepared in Example 1, wherein Figure a is the valence band spectrum and Figure b is the Tauc diagram.
图4为实施例1制备的催化剂的能带结构图。Figure 4 is a diagram of the energy band structure of the catalyst prepared in Example 1.
图5为实施例1制备的催化剂在光催化水产氢-5-HMF氧化偶联反应中的产氢量随时间的变化折线图。Fig. 5 is a line graph showing the change of the amount of hydrogen produced by the catalyst prepared in Example 1 in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction with time.
图6为实施例1制备的催化剂在光催化水产氢-5-HMF氧化偶联反应中反应液的HPLC谱图，其中图a为反应前的HPLC谱图，图b为反应6h后的HPLC谱图。Figure 6 is the HPLC spectrogram of the reaction solution in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction of the catalyst prepared in Example 1, wherein Figure a is the HPLC spectrum before the reaction, and Figure b is the HPLC spectrum after the reaction for 6h picture.
图7为实施例1制备的催化剂在光催化水产氢-5-HMF氧化偶联反应中的产物FDCA的浓度随时间变化曲线，5-HMF的转化率和FDCA选择性曲线。其中图a为产物FDCA的浓度随时间变化曲线，图b为5-HMF的转化率和FDCA选择性曲线。Fig. 7 is the time-varying curve of the concentration of FDCA, the conversion rate of 5-HMF and the FDCA selectivity curve of the catalyst prepared in Example 1 in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction. Wherein, figure a is the concentration curve of the product FDCA with time, and figure b is the conversion rate of 5-HMF and the selectivity curve of FDCA.
具体实施方式：detailed description:
实施例1Example 1
以可溶性硝酸盐(Cu(NO 3) 2·3H 2O、Al(NO 3) 3·9H 2O和Co(NO 3) 2·6H 2O)作为金属盐，配制Cu 2+、Co 2+与Al 3+金属摩尔比为1:5:2的混合盐溶液，加入碱溶液以保持体系pH范围恒定在10±0.1，共沉淀得到CuCoAl-CO 3 2--LDHs类水滑石前驱体。将得到的前驱体置于管式炉中，在氢气体积分数为10％的H 2/N 2气氛下保持气流速度为30mL/min，以2℃/min的升温速率将管式炉炉温升至600℃并恒温保持4h。反应结束，为避免催化剂氧化，将炉温自然冷却至室 温，得到Cu/CoAlO催化剂，其中Cu/Co摩尔比为1/5，Cu、Co和Al元素质量百分含量分别为8.3％、42.7％和7.8％。对得到的样品进行表征，结果见图1-图4，由表征结果可见，该催化剂金属纳米颗粒呈现出Co@CuCo合金的核壳结构，并且金属纳米颗粒均匀地分散在无定形的Al 2O 3载体上，纳米颗粒平均尺寸为5.8nm。该催化剂的价带(VB)值为1.73eV，导带(CB)值为-0.94eV，导带值满足将H质子还原为氢气的热力学要求，价带值既满足产氧所需的VB值(1.23eV)，也达到了5-HMF氧化所需的VB值(0.82eV)。 Cu 2+ , Co 2+ _ _ _ _ _ _ Mixed salt solution with Al 3+ metal molar ratio of 1:5:2, adding alkali solution to keep the pH range of the system constant at 10±0.1, co-precipitate to obtain CuCoAl-CO 3 2- -LDHs-like hydrotalcite precursor. The obtained precursor was placed in a tube furnace, and the gas flow rate was kept at 30mL/min under an H2 / N2 atmosphere with a hydrogen fraction of 10%, and the temperature of the tube furnace was raised at a rate of 2°C/min. to 600°C and kept at constant temperature for 4h. After the reaction is over, in order to avoid catalyst oxidation, the furnace temperature is naturally cooled to room temperature to obtain a Cu/CoAlO catalyst, wherein the Cu/Co molar ratio is 1/5, and the mass percentages of Cu, Co and Al elements are 8.3%, 42.7% respectively and 7.8%. The obtained samples were characterized, and the results are shown in Fig. 1-Fig. 4. It can be seen from the characterization results that the catalyst metal nanoparticles present a core-shell structure of Co@CuCo alloy, and the metal nanoparticles are uniformly dispersed in the amorphous Al 2 O 3 on the carrier, the average size of nanoparticles is 5.8nm. The valence band (VB) value of the catalyst is 1.73eV, and the conduction band (CB) value is -0.94eV. The conduction band value meets the thermodynamic requirements for reducing H protons to hydrogen, and the valence band value meets the VB value required for oxygen production. (1.23eV), also reached the VB value (0.82eV) required for the oxidation of 5-HMF.
将上述得到的催化剂用于光催化水产氢-5-HMF氧化偶联反应中，具体方法是：在容积为20mL的可密封的反应器中，先加入5mg催化剂和13mg 5-羟甲基糠醛，再加入10mL纯净水，用压盖器密封。在磁力搅拌下，用高纯Ar置换反应瓶中的空气30min，然后打开300W Xe灯(>380nm)，保持灯与反应瓶距离约5cm，灯电流强度为16A，照射反应液，磁力搅拌转速设为600rpm，反应时间为6h。分别在反应时间1，2，3，4，5，6h时取样，气相产物的浓度和含量用气相色谱进行检测，液相产物的分布和含量用高效液相色谱进行分析。结果见表1，由表1可以看出，反应6h后，该催化剂在无外加碱的条件下，FDCA选择性为95.5％，6h后的产氢量为9.78μmol，最高产氢速率可达888.3μmolh -1g -1。 The catalyst obtained above is used in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction. The specific method is: in a sealable reactor with a volume of 20mL, first add 5mg of catalyst and 13mg of 5-hydroxymethylfurfural, Then add 10mL of pure water and seal it with a capper. Under magnetic stirring, replace the air in the reaction bottle with high-purity Ar for 30 minutes, then turn on the 300W Xe lamp (>380nm), keep the distance between the lamp and the reaction bottle about 5cm, and the lamp current intensity is 16A, irradiate the reaction solution, and the magnetic stirring speed is set to It is 600rpm, and the reaction time is 6h. Samples were taken at 1, 2, 3, 4, 5, and 6 hours of reaction time, the concentration and content of gas phase products were detected by gas chromatography, and the distribution and content of liquid phase products were analyzed by high performance liquid chromatography. The results are shown in Table 1. It can be seen from Table 1 that after 6 hours of reaction, the FDCA selectivity of the catalyst was 95.5% without adding alkali, the hydrogen production amount after 6 hours was 9.78 μmol, and the highest hydrogen production rate could reach 888.3 μmolh -1 g -1 .
实施例2Example 2
按照实施例1的方法制备Cu/CoAlO催化剂，所不同的是混合盐溶液中Cu、Co与Al的金属摩尔比为1:4:2，得到的催化剂中Cu、Co和Al元素质量百分含量分别为9.6％、37.6％和8.5％。The Cu/CoAlO catalyst is prepared according to the method of Example 1, the difference is that the metal molar ratio of Cu, Co and Al in the mixed salt solution is 1:4:2, and the mass percentage of Cu, Co and Al elements in the obtained catalyst 9.6%, 37.6% and 8.5% respectively.
按照实施例1的方法将得到的催化剂用于光催化水产氢-5-HMF氧化偶联反应中，结果见表1，由表1可以看出反应6h后，该催化剂在无外加碱的条件下FDCA选择性为94.3％，6h后的产氢量为8.03μmol，最高产氢速率可达798.0μmolh -1g -1。 According to the method of Example 1, the obtained catalyst was used in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, the results are shown in Table 1, and it can be seen from Table 1 that after 6 hours of reaction, the catalyst was under the condition of no additional alkali The selectivity of FDCA is 94.3%, the hydrogen production amount after 6h is 8.03μmol, and the highest hydrogen production rate can reach 798.0μmolh -1 g -1 .
实施例3Example 3
按照实施例1的方法制备Cu/CoAlO催化剂，所不同的是混合盐溶液中Cu、Co与Al的金属摩尔比为1:3:2，焙烧还原温度为550℃；得到的催化剂中Cu、Co和Al元素质量百分含量分别为10.8％、33.7％和10.4％。The Cu/CoAlO catalyst was prepared according to the method of Example 1, except that the metal molar ratio of Cu, Co and Al in the mixed salt solution was 1:3:2, and the calcination reduction temperature was 550°C; the obtained catalyst contained Cu, Co The mass percent contents of Al and Al elements are 10.8%, 33.7% and 10.4%, respectively.
按照实施例1的方法将得到的催化剂用于光催化水产氢-5-HMF氧化偶联反应中，结果见表1，由表1可以看出反应6h后，该催化剂在无外加碱的条件下FDCA选择性为94.5％，6h后的产氢量为7.4μmol，最高产氢速率可达796.8μmolh -1g -1。 According to the method of Example 1, the obtained catalyst was used in the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction, the results are shown in Table 1, and it can be seen from Table 1 that after 6 hours of reaction, the catalyst was under the condition of no additional alkali The selectivity of FDCA is 94.5%, the hydrogen production amount after 6h is 7.4μmol, and the highest hydrogen production rate can reach 796.8μmolh -1 g -1 .
表1Table 1
Figure PCTCN2022099795-appb-000002
Figure PCTCN2022099795-appb-000002
Figure PCTCN2022099795-appb-000003
Figure PCTCN2022099795-appb-000003
其中对比例1与对比例2都是光催化水产氢-5-HMF氧化偶联反应的文献值。对比例1是文献1中Ni/CdS NSs催化剂在反应6h后的产氢量，在反应22h后DFF选择性，但该催化剂在反应体系中加入强碱后，DFF会快速转化为FDCA。对比例2是文献2中Zn xCd 1-xS-P催化剂在反应8h后的性能。 Among them, Comparative Example 1 and Comparative Example 2 are the literature values of the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction. Comparative example 1 is the hydrogen production of the Ni/CdS NSs catalyst in Document 1 after 6 hours of reaction, and the DFF selectivity after 22 hours of reaction, but the catalyst will quickly convert DFF to FDCA after adding a strong base to the reaction system. Comparative Example 2 is the performance of the Zn x Cd 1-x SP catalyst in Document 2 after 8 hours of reaction.
从表1看出，本发明催化剂在无外加碱条件下对于2,5-呋喃二甲酸(FDCA)的选择性较高，均高于对比例，实现了中性条件下由5-羟甲基糠醛(5-HMF)向2,5-呋喃二甲酸(FDCA)的高效定向转化。As can be seen from Table 1, the catalyst of the present invention has higher selectivity for 2,5-furandicarboxylic acid (FDCA) under the condition of no external base, which is higher than that of the comparative example, and the 5-hydroxymethyl Efficient and targeted conversion of furfural (5-HMF) to 2,5-furandicarboxylic acid (FDCA).

Claims (3)

  1. 一种Cu基催化剂，其特征是该Cu基催化剂的化学表示式为Cu/CoAlO，其中Cu与Co的摩尔比为1:3～1:5，Co和Al的摩尔比为1.5～2.5；该催化剂的结构特点是Cu和Co物种在载体表面形成具有Co@CuCo核壳结构的金属纳米颗粒且金属颗粒均匀分布，金属颗粒平均粒径为2～10nm；该催化剂的价带值VB＝1.7～2.0eV，导带值CB为-0.8～-1.0eV；Cu/CoAlO催化剂是由含Cu 2+、Co 2+和Al 3+金属离子的水滑石作为前驱体，在H 2/N 2或H 2/Ar的混合气氛下550～650℃高温焙烧得到的；5-HMF代表5-羟甲基糠醛。 A Cu-based catalyst is characterized in that the chemical expression of the Cu-based catalyst is Cu/CoAlO, wherein the molar ratio of Cu to Co is 1:3 to 1:5, and the molar ratio of Co to Al is 1.5 to 2.5; the The structural feature of the catalyst is that Cu and Co species form metal nanoparticles with a Co@CuCo core-shell structure on the surface of the carrier, and the metal particles are evenly distributed, and the average particle size of the metal particles is 2-10 nm; the valence band value of the catalyst is VB=1.7- 2.0eV, the conduction band value CB is -0.8～-1.0eV; Cu/CoAlO catalyst is made of hydrotalcite containing Cu 2+ , Co 2+ and Al 3+ metal ions as the precursor, in H 2 /N 2 or H 2 /Ar under the mixed atmosphere of 550 ~ 650 ℃ high temperature roasting; 5-HMF stands for 5-hydroxymethylfurfural.
  2. 一种权利要求1所述的Cu基催化剂的应用，其特征是该催化剂专用于光催化水产氢-5-HMF氧化偶联反应An application of the Cu-based catalyst according to claim 1, characterized in that the catalyst is dedicated to the photocatalytic water hydrogen production-5-HMF oxidative coupling reaction
  3. 根据权利要求2所述的Cu基催化剂的应用，具体应用步骤是：向可密封的反应器中加入反应物5-HMF、Cu/CoAlO和去离子水，其中5-HMF和Cu/CoAlO的质量比为2～6，5-HMF的质量浓度为1.0～3.3g/L；在磁力搅拌下，用高纯Ar充分置换反应瓶中的空气，用300W Xe灯(λ>380nm)照射反应液，在充分搅拌下反应1～8h，得到FDCA产品；该反应的特点是在无外加碱的条件下进行。According to the application of Cu-based catalyst according to claim 2, the specific application steps are: add reactant 5-HMF, Cu/CoAlO and deionized water in the sealable reactor, wherein the quality of 5-HMF and Cu/CoAlO The ratio is 2-6, and the mass concentration of 5-HMF is 1.0-3.3g/L; under magnetic stirring, fully replace the air in the reaction bottle with high-purity Ar, and irradiate the reaction solution with a 300W Xe lamp (λ>380nm). React for 1-8 hours under sufficient stirring to obtain FDCA product; the characteristic of this reaction is that it is carried out without adding alkali.
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