Efficient ionic liquid coupled solid catalyst and application thereof in electrocatalytic oxidation of 5-hydroxymethylfurfural

Abstract

The invention discloses a method for electrooxidation of 5-hydroxymethylfurfural (HMF) by using an ionic liquid coupled solid catalyst. A two-dimensional conductive metal organic framework catalyst Ni-HHTP is synthesized through a hydrothermal method, and on the basis, ionic liquid [MTBD] [NTf2] is introduced through a rotary evaporation method, so that the ionic liquid is coupled with a solid catalyst, and the optimal catalyst Ni-HHTP-0. 5 [MTBD] [NTf2] is obtained. The material is subjected to systematic structural characterization and electrochemical performance test through multiple characterization means, and the obtained catalyst has good electrochemical activity and stability and high FDCA Faraday efficiency and yield. The addition of the ionic liquid improves the HMF electrooxidation performance of the catalyst, and has a certain promotion effect on an HMF oxidation system. Biomass resources can be efficiently converted, high-added-value chemicals can be prepared, and the preparation method is simple, safe and free of pollution.

Description

Technical Field

[0001] This invention relates to the field of electrochemical catalysis, specifically to an ionic liquid-coupled solid catalyst and its application in the electrooxidation of 5-hydroxymethylfurfural (HMF). By comparing the performance of catalysts modified with and without ionic liquids, this invention demonstrates the significant advantages of ionic liquid-modified metal-organic frameworks (MOFs) in improving the efficiency and selectivity of HMF electrocatalytic oxidation. This technology has broad applications in green chemical synthesis and biomass conversion. Background Art

[0002] With increasing global attention to sustainable development and environmental protection, the efficient conversion and utilization of biomass resources has become a research hotspot. 5-Hydroxymethylfurfural, as an important biomass platform compound, offers abundant resources and broad industrial application prospects. Its oxidation product, 2,5-furandicarboxylic acid (FDCA), is a key monomer for bio-based polyesters and can be used to produce biodegradable plastics, fibers, and other high-value-added materials. However, traditional HMF oxidation methods typically require high temperature and high pressure and suffer from poor selectivity, high energy consumption, and environmental pollution. In recent years, electrochemical oxidation has attracted widespread attention as a green and efficient biomass conversion technology. This method can be carried out at room temperature and pressure, offering advantages such as mild reaction conditions and environmental friendliness. Furthermore, electrocatalytic HMF oxidation can replace the kinetically slow anodic oxygen evolution reaction, enabling the efficient production of high-value-added biomass-derived chemicals while also achieving low-energy hydrogen production. However, current catalysts for HMF electrooxidation still suffer from insufficient activity, low selectivity, and poor stability, limiting their industrial application. To overcome these challenges, researchers are committed to developing new, efficient electrocatalysts to improve HMF conversion and FDCA selectivity.

[0003] In this context, ionic liquids, as green solvents and modifiers, have been widely studied due to their unique physicochemical properties (such as high thermal stability, low volatility and good electrochemical performance). Metal-organic framework materials, such as Ni-HHTP, have shown great potential in the field of electrocatalysis due to their special structure, high specific surface area, modifiable pore surface and adjustable pore size. The coupling of ionic liquids with solid catalysts is expected to significantly improve the performance of the catalyst by optimizing the microenvironment of the reaction interface. However, there are still few studies on the application of ionic liquid-modified metal-organic framework catalysts in HMF electrooxidation, and there is a lack of systematic comparative studies to verify their performance advantages.

[0004] Therefore, developing an efficient and stable ionic liquid-modified catalyst and in-depth study of its application in HMF electrooxidation are of great significance for promoting the green conversion of biomass resources and the development of renewable chemical industry. Summary of the Invention

[0005] The purpose of the present invention is to provide an efficient and structurally optimized ionic liquid composite solid catalyst, which abandons the cumbersome preparation process and dependence on complex reagents, and prepares a catalyst for the electrocatalytic oxidation of HMF only by the method of ionic liquid modification. The catalytic material has a high specific surface area and abundant active sites. The electrochemical performance of the Ni-HHTP catalyst is optimized by introducing ionic liquids, and its catalytic behavior in the HMF electrooxidation reaction is systematically studied. The raw materials involved in the preparation method are low in cost, the process steps are simple and easy to implement, and it exhibits excellent catalytic performance and stability. Due to its excellent solubility, ionic liquids can improve the catalytic activity and the yield of the target product FDCA and the Faraday efficiency by enriching the substrate concentration.

[0006] The obtained catalyst is mainly composed of metal organic framework compounds and ionic liquids. The synthesized catalyst has a nanorod morphology with a size range of about 400nm and an electrochemical active area of ​​3.28mF / cm 2 Under the conditions of 1.4V vs. RHE and electrolysis to 58°C, the conversion of HMF was close to 100%, the yield of FDCA was also close to 100%, and the Faradaic efficiency of FDCA was 96.98%. After 6 cycles, the FDCA yield ranged from 94% to 99.99%, and the Faradaic efficiency ranged from 91% to 96.98%.

[0007] To achieve the above results, the following technical solutions are mainly used:

[0008] (1) Hexahydroxytriphenylene (HHTP) and nickel(II) acetate tetrahydrate (Ni(OAc)2·4H2O) were uniformly mixed in a hydrothermal method and dissolved in a beaker of deionized water. The solution was ultrasonically treated and then transferred to a polytetrafluoroethylene-lined autoclave. The reaction was carried out in a forced air drying oven, followed by multiple centrifugal washings and drying to form Ni-HHTP.

[0009] (2) 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene ([MTBD]) and lithium bis(trifluoromethanesulfonyl)imide were used to synthesize the [MTBD][NTf2] ionic liquid in a certain ratio. The [MTBD] solution was cooled in an ice bath, and nitric acid was gradually added to the [MTBD] solution. The pH value was accurately monitored and adjusted using a pH meter until the pH value was close to neutral. After the [MTBD] solution was neutralized, the Li[NTf2] solution was slowly added and thoroughly mixed, and precipitated in the aqueous phase as a viscous phase.

[0010] (3) Dissolve the ionic liquid in isopropanol. In an eggplant-shaped flask containing isopropanol, dissolve the Ni-HHTP and the calculated volume of the IL, ensuring thorough mixing. Evaporate the solvent using a rotary evaporator. Maintain a vacuum of 10 Pa and continue the rotary evaporation for 1 hour. Dry overnight in a high vacuum to obtain the Ni-HHTP-IL catalyst.

[0011] (4) The carbon paper was subjected to a series of cleaning steps, including ultrasonic treatment in 3M HCl solution for 30 minutes to remove surface oxides; then ultrasonic treatment in acetone for 30 minutes to remove organic pollutants; and finally ultrasonic treatment in ethanol for 30 minutes to further clean the surface, and finally ultrasonic cleaning with deionized water for 30 minutes and drying.

[0012] (5) In order to obtain Ni-HHTP-IL materials with different HMF electrooxidation performance, the method of changing the ionic liquid loading amount and the type of ionic liquid was adopted. While keeping the processes (1)-(4) unchanged, according to the mass ratio of nickel contained in IL to Ni-HHTP, m IL / m Ni The Ni-HHTP-IL with different ratios was obtained by measuring the corresponding volume of ionic liquid and changing the type of ionic liquid to [BMIM][NTf2], [BMIM][OH] to obtain different catalysts.

[0013] Preferably, in the step (1), the reaction mixture is heated to 85° C. for 12 hours.

[0014] Preferably, in step (2), equimolar amounts of precursors are used, and the [MTBD] solution is cooled to approximately 0°C.

[0015] Preferably, in step (3), the rotary evaporator is set to 40° C. and 60 rpm / min.

[0016] Preferably, in step (4), hydrophobic carbon paper is selected, and 0.5 mg / cm 2 Catalyst onto carbon paper.

[0017] Preferably, in the step (5), the ionic liquid in IL and Ni-HHTP is [MTBD][NTf2] and the mass ratio of nickel contained is m IL / m Ni When the mass ratio of the other two ionic liquids is m IL / m Ni When it is 0.1, it is the optimal ratio.

[0018] The invention also discloses a catalyst of multiple ionic liquid coupling prepared by the preparation method.

[0019] The present invention also discloses the application of the ionic liquid coupled catalyst in the HMF electrocatalytic oxidation system for preparing FDCA.

[0020] Compared with the prior art, the present invention has the following obvious outstanding substantial features and significant advantages:

[0021] 1. The concept of ionic liquid-coupled solid catalysts was applied to the HMF electrooxidation system for the first time, demonstrating excellent HMF electrocatalytic performance. The preparation method is simple, safe, and pollution-free, resulting in a highly efficient catalyst.

[0022] 2. The catalyst prepared by the present invention exhibits excellent electrochemical activity and stability, with high HMF conversion, FDCA Faradaic efficiency, and yield. The addition of an ionic liquid enhances the catalyst's HMF electrooxidation performance and promotes the HMF oxidation system. This allows for the efficient conversion of biomass resources to produce high-value-added chemicals, providing important support for addressing energy shortages, reducing environmental pollution, and promoting the development of a green economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a scanning electron microscope (SEM) image of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP catalyst.

[0024] Figure 2 It is a transmission electron microscopy (TEM) image of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP catalyst.

[0025] Figure 3 This is the X-ray photoelectron spectrum (XPS) diagram of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP catalyst.

[0026] Figure 4 It is the Fourier transform infrared (FT-IR) spectrum of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP catalyst.

[0027] Figure 5 This is the nitrogen isothermal adsorption-desorption curve of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP catalyst.

[0028] Figure 6 This is the electrochemical activity area (ECSA) diagram of Ni-HHTP, Ni-HHTP-0.1[MTBD][NTf2], Ni-HHTP-0.5[MTBD][NTf2], Ni-HHTP-0.1[BMIM][NTf2] and Ni-HHTP-0.1[BMIM][OH] catalysts.

[0029] Figure 7 Linear sweep voltammetry (LSV) curves of Ni-HHTP, Ni-HHTP-0.1[MTBD][NTf2], Ni-HHTP-0.5[MTBD][NTf2], Ni-HHTP-0.1[BMIM][NTf2], and Ni-HHTP-0.1[BMIM][OH] catalysts.

[0030] Figure 8 This is a comparison chart of HMF conversion, FDCA yield and Faradaic efficiency of Ni-HHTP, Ni-HHTP-0.1[MTBD][NTf2], Ni-HHTP-0.5[MTBD][NTf2], Ni-HHTP-0.1[BMIM][NTf2] and Ni-HHTP-0.1[BMIM][OH] catalysts.

[0031] Figure 9 This is the cycling stability diagram of Ni-HHTP-0.5[MTBD][NTf2]. DETAILED DESCRIPTION

[0032] The above solution is further described below with reference to specific implementation examples. The preferred embodiments of the present invention are described in detail as follows:

[0033] Example 1

[0034] (1) 70 mg of hexahydroxytriphenylene (HHTP) and 100 mg of nickel (II) acetate tetrahydrate (Ni(OAc)2·4H2O) were dissolved in 40 mg of deionized water using a hydrothermal method. The solution was treated in an ultrasonic device for 2 to 3 hours and then continued to react in a forced air drying oven at 85°C for 12 hours to obtain dark blue crystals. The solution was cooled naturally to room temperature, washed with deionized water and acetone multiple times, and dried to a catalyst powder using a freeze dryer to obtain the catalyst Ni-HHTP.

[0035] (2) [MTBD][NTf2] ionic liquid was dissolved in a ratio of 1 μL IL / mL isopropanol, and then the mass ratio of IL to nickel contained in Ni-HHTP was calculated. IL / m Ni =0.1, measure the corresponding volume of ionic liquid

[0036] (3) Dissolve 10 mg of Ni-HHTP and the calculated volume of IL in an eggplant-shaped flask containing 5 mL of isopropanol and sonicate for 1 h. Then, evaporate to dryness using a rotary evaporator, maintain a vacuum of 10 Pa, and continue evaporation for 1 h. Dry in a high vacuum to obtain the Ni-HHTP-0.1[MTBD][NTf2] catalyst.

[0037] Example 2

[0038] The [MTBD][NTf2] ionic liquid was dissolved in 1 μL IL / mL isopropanol, and then the mass ratio of IL to nickel contained in Ni-HHTP was calculated. IL / m Ni The reaction mixture was 0.5, and the corresponding volume of ionic liquid was measured. The subsequent steps were the same as step (3) of Example 1 to obtain Ni-HHTP-0.5[MTBD][NTf2] catalyst.

[0039] Comparative Example 1

[0040] The difference between this comparative example and Example 1 is that the step (2) of introducing the ionic liquid is omitted, and the remaining implementation conditions are the same as those in Example 1 to obtain a Ni-HHTP catalyst.

[0041] Comparative Example 2

[0042] The difference between this comparative example and Example 1 is that the [MTBD][NTf2] ionic liquid introduced in step (2) is replaced with [BMIM][NTf2] ionic liquid, and the remaining implementation conditions are the same as those in Example 1 to obtain Ni-HHTP-0.1[BMIM][NTf2] catalyst.

[0043] Comparative Example 3

[0044] The difference between this comparative example and Example 1 is that the [MTBD][NTf2] ionic liquid introduced in step (2) is replaced with [BMIM][OH] ionic liquid, and the other implementation conditions are the same as those in Example 1 to obtain Ni-HHTP-0.1[BMIM][OH] catalyst.

[0045] The prepared catalyst was characterized in terms of morphology, structure and electrochemical performance:

[0046] Experimental Example 1

[0047] The scanning electron microscopy (SEM) images of the catalysts prepared in Example 2 (Ni-HHTP-0.5[MTBD][NTf2]) and Comparative Example 1 (Ni-HHTP) are as follows: Figure 1 As shown in the figure, it can be seen that Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP both exhibit the same nanorod-like structure with a diameter of about 400 nm and a relatively uniform size, indicating that the synthesis conditions are relatively stable and that the addition of ionic liquids does not change the morphology and microstructure of the catalyst.

[0048] Transmission electron microscopy (TEM) of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP Figure 2As shown in the figure, both Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP exhibit nanorod-like structures. The ionic liquid is uniformly dispersed within the Ni-HHTP pores without causing aggregation or morphological changes, demonstrating good compatibility and high dispersibility between the ionic liquid and the material. The absence of localized aggregation or pore blockage, therefore maintaining a stable overall morphology, is also evident.

[0049] The X-ray photoelectron spectra (XPS) of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP are as follows Figure 3 The full XPS spectrum of Ni-HHTP (Figure a) shows the presence of Ni, C, and O elements, while the ionic liquid [MTBD][NTf2] contains N, F, S, and other elements. The full XPS spectrum of Ni-HHTP-0.5[MTBD][NTf2] (Figure b) shows the presence of Ni, C, O, N, F, and S elements, confirming that the ionic liquid was successfully introduced and highly dispersed in Ni-HHTP, that is, the Ni-HHTP-0.5[MTBD][NTf2] catalyst was successfully synthesized.

[0050] The Fourier transform infrared spectra (FT-IR) of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP are as follows Figure 4 From the infrared spectrum of Ni-HHTP-0.5[MTBD][NTf2], it was observed that there were sulfonyl groups and CF bonds, while the absorption peak characteristics corresponding to Ni-HHTP were retained, indicating that the ionic liquid was highly dispersed in Ni-HHTP, which was consistent with the results of the XPS full spectrum analysis.

[0051] The nitrogen isothermal adsorption and desorption curves of Ni-HHTP-0.5[MTBD][NTf2] and Ni-HHTP are shown in the figure. Figure 5 It shows a typical IV type adsorption-desorption curve with obvious hysteresis loop, which indicates that both have microporous / mesoporous structures. The BET specific surface area of ​​Ni-HHTP is 487.7m 2 / g, after the addition of ionic liquid, the BET specific surface area decreased to 90.1m 2 / g, and the pore volume and pore size decreased, indicating that the IL molecules were successfully filled into the pores, possibly filling the micropores or mesopores of the catalyst, which once again confirmed the successful introduction of ionic liquids into Ni-HHTP.

[0052] Experimental Example 2

[0053] First, the working electrode was prepared. 2.5 mg of each catalyst (Ni-HHTP, Ni-HHTP-0.1[MTBD][NTf2], Ni-HHTP-0.5[MTBD][NTf2], Ni-HHTP-0.1[BMIM][NTf2], and Ni-HHTP-0.1[BMIM][OH]) was weighed and added to a mixture of 360 μL of isopropanol, 120 μL of deionized water, and 20 μL of 5 wt% Nafion solution. Next, an ultrasonic treatment was performed for at least 30 minutes to obtain a slurry (ink) with a uniform dispersion of the catalysts. A certain amount of ink was drop-coated onto a 1 cm x 1 cm area of ​​carbon paper and dried using an infrared lamp to serve as the working electrode. A three-electrode system was employed, with the aforementioned catalysts serving as the working electrode, a platinum sheet as the counter electrode, and Hg / HgO as the reference electrode. The electrolyte used in the tests was 1.0 M KOH with or without 10 mM HMF. LSV tests were performed in a 30 mL single-chamber electrolytic cell with a scan rate of 5 mV·s. -1 , the voltage range is 0-1.2V (vs.Hg / HgO), and the speed is 1200r / min to ensure the consistency of test conditions.

[0054] The electrochemical activity area diagram of the catalysts prepared in Comparative Example 1 (Ni-HHTP), Example 1 (Ni-HHTP-0.1[MTBD][NTf2]), Example 2 (Ni-HHTP-0.5[MTBD][NTf2]), Comparative Example 2 (Ni-HHTP-0.1[BMIM][NTf2]) and Comparative Example 3 (Ni-HHTP-0.1[BMIM][OH]) is shown in FIG. Figure 6 As shown in the figure, the electrode with ionic liquid added has a higher ECSA than the electrode without ionic liquid, which significantly improves the ECSA of the catalyst, indicating that the ionic liquid optimizes the surface properties and electrochemical activity of the catalyst. [MTBD][NTf2] has the best effect, especially at a higher loading (0.5), with the ECSA reaching a maximum of 3.28mF / cm 2 , indicating that its chemical structure and loading are crucial to the improvement of catalytic performance. The introduction of ionic liquid gives Ni-HHTP-0.5[MTBD][NTf2] material a higher electrochemically active surface area.

[0055] The LSV curves of Ni-HHTP, Ni-HHTP-0.1[MTBD][NTf2], Ni-HHTP-0.5[MTBD][NTf2], Ni-HHTP-0.1[BMIM][NTf2] and Ni-HHTP-0.1[BMIM][OH] catalysts are shown in Figure 2. Figure 7As shown. First, Ni-HHTP and Ni-HHTP-0.5[MTBD][NTf2] were compared. The current density of Ni-HHTP-0.5[MTBD][NTf2] with ionic liquid added was significantly higher than that of unmodified Ni-HHTP, indicating that the introduction of [MTBD][NTf2] ionic liquid significantly improved the electrochemical activity of the catalyst, indicating that the ionic liquid played a certain role in HMFOR. Secondly, Ni-HHTP-0.1[MTBD][NTf2] and Ni-HHTP-0.5[MTBD][NTf2] catalysts were compared. In the electrolyte containing HMF, when the mass ratio of ionic liquid to nickel was 0.5, the current density reached the maximum value, which was significantly higher than the performance at other ratios. This shows that the addition of ionic liquid with a mass ratio of 0.5 can effectively optimize the Ni-HHTP catalyst and improve the electrocatalytic performance of the catalyst Ni-HHTP. Then, the current densities of Ni-HHTP-0.5[MTBD][NTf2], Ni-HHTP-0.1[BMIM][NTf2] and Ni-HHTP-0.1[BMIM][OH] catalysts were compared, and it was found that the current density of the former was higher than that of the latter two, indicating that different ionic liquids have different effects on catalyst modification. The ionic liquid [MTBD][NTf2] has a better effect on improving catalytic performance than [BMIM][NTf2] and [BMIM][OH], which further shows that the chemical structure or properties of ionic liquids have a significant influence on catalytic performance.

[0056] The comparison chart of HMF conversion rate, FDCA yield and Faraday efficiency obtained by HMF electrooxidation of the above five catalysts is as follows: Figure 8 As shown. The HMF electrooxidation reaction was carried out in an H-type electrolytic cell with a volume of 10 mL, in which the two chambers were separated by a Nafion 117 proton exchange membrane. The electrolyte on the anode side was a 1M KOH solution containing 10 mM HMF, and the electrolyte on the cathode side was a 1M KOH solution. At a potential of 1.4 V vs. RHE, comparing the data in the figure, it was found that Ni-HHTP-0.5[MTBD][NTf2] had the best electrooxidation performance, with a HMF conversion rate close to 100%, a FDCA yield close to 100%, and a Faraday efficiency of FDCA of 96.98%. The above shows that the Ni-HHTP-0.5[MTBD][NTf2] catalyst prepared by the present invention has good catalytic activity in the direction of HMF electrooxidation.

[0057] The cyclic stability of Ni-HHTP-0.5[MTBD][NTf2] catalyst is shown in Figure 2. Figure 9As shown, after six consecutive cycles of HMF electrooxidation, Ni-HHTP-0.5[MTBD][NTf2] maintained a nearly 100% HMF conversion, FDCA yields ranging from 94% to 99.99%, and Faradaic efficiencies ranging from 91% to 96.98%. These results demonstrate that the Ni-HHTP-0.5[MTBD][NTf2] catalyst prepared in this invention exhibits excellent stability in the electrocatalytic oxidation of HMF to FDCA.

[0058] In summary, the present invention synthesizes a two-dimensional conductive metal-organic framework catalyst, Ni-HHTP, via a hydrothermal method. Furthermore, a rotary evaporation method is used to introduce different types of ionic liquids and different ratios of ionic liquid [MTBD][NTf2], thereby coupling the ionic liquid to the solid catalyst, resulting in the optimal catalyst, Ni-HHTP-0.5[MTBD][NTf2]. This catalyst exhibits excellent electrochemical activity and stability. The addition of the ionic liquid improves the catalyst's HMF electrooxidation performance and has a certain promoting effect on the HMF oxidation system. The above-described embodiments of the present invention demonstrate a simple preparation method, simple process equipment, stable and controllable product performance, environmentally friendly raw materials, and high reproducibility.

Claims

1. A method for preparing an ionic liquid coupled solid catalyst, characterized in that: The following steps are involved: (1) A two-dimensional conductive metal-organic framework catalyst Ni-HHTP was synthesized by hydrothermal synthesis using hexahydroxytriphenylene and nickel(II) acetate tetrahydrate. (2) The synthesized ionic liquid was dissolved in isopropanol in a certain proportion. In an eggplant-shaped flask containing isopropanol, Ni-HHTP and the calculated volume of the obtained IL were dissolved according to the proportion to ensure complete mixing. (3) Using a rotary evaporator, set the parameters to evaporate the solvent. Maintain a vacuum of 10 Pa and continue the rotary evaporation process for 1 hour. Dry overnight in a high vacuum to obtain the ionic liquid-coupled catalyst Ni-HHTP-IL.

2. The method for preparing an ionic liquid coupled solid catalyst according to claim 1, characterized in that: The reaction temperature of the hydrothermal synthesis method is 85° C., the reaction time is 12 h, and the size range of the obtained catalyst particles is about 500 nm.

3. The method for preparing an ionic liquid coupled solid catalyst according to claim 1, characterized in that: The ionic liquid is [MTBD][NTf2], which is characterized in that it is a hydrophobic ionic liquid with excellent dissolving ability.

4. The method for preparing an ionic liquid coupled solid catalyst according to claim 1, characterized in that: The ionic liquid is synthesized from 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and lithium bis(trifluoromethanesulfonyl)imide in an equimolar ratio.

5. The method for preparing an ionic liquid coupled solid catalyst according to claim 1, characterized in that: The ionic liquid was dissolved in isopropanol at a ratio of 1 μL 1L / mL.

6. The method for preparing an ionic liquid coupled solid catalyst according to claim 1, characterized in that: The dissolution ratio is the mass ratio of IL to nickel contained in Ni-HHTP. IL / m Ni Dissolved at 0.

5.

7. The method for preparing an ionic liquid coupled solid catalyst according to claim 1, characterized in that: The parameters of the rotary evaporator are 40° C. and 60 rpm / min.

8. An ionic liquid coupled solid catalyst, characterized in that The method is prepared according to any one of claims 1 to 7.

9. Use of the ionic liquid coupled solid catalyst according to claim 8 in a system for preparing FDCA by electrocatalytic oxidation of HMF.

Images