A method for rapidly preparing a NiFe-LDH / FeOOH catalyst to electrocatalytically oxidize HMF

Abstract

The application discloses a method for rapidly preparing a NiFe-LDH / FeOOH catalyst for electrocatalytic oxidation of HMF. The method uses a foamed nickel as a carrier, and the carrier is placed in a mixed solution of hydrogen peroxide and an iron salt through a Fenton method, so that the NiFe-LDH / FeOOH catalyst can be obtained after a certain time. The catalyst is used as a working electrode, and a three-electrode system is used to realize electrocatalytic oxidation of HMF (5-hydroxymethylfurfural) into FDCA (2,5-furan dicarboxylic acid) under mild conditions. The layered transition metal (Ni, Fe) hydroxide and iron hydroxyl oxide catalyst prepared by the application has excellent electrocatalytic performance, the consumption of noble metals required by traditional catalysts is avoided in the preparation process, and the cost is effectively reduced. Meanwhile, the electrocatalytic oxidation reaction process is mild, green, pollution-free, simple in operation, and can be completed in a short time, has high raw material conversion rate, good product selectivity, high Faraday efficiency, and has great industrialization prospect.

Description

Technical Field

[0001] This invention relates to a rapid catalyst preparation method, and more particularly to a method for selectively oxidizing HMF (5-hydroxymethylfurfural) to 2,5-furandicarboxylic acid on a NiFe-LDH (layered bimetallic hydroxide) / FeOOH catalyst. Background Technology

[0002] Human overexploitation of fossil resources and dependence on petroleum-based chemicals have caused severe environmental pollution, resource shortages, and the global greenhouse effect, among other acute problems. Research on the development and utilization of clean and renewable energy is crucial for solving these problems. Biomass, the only renewable organic carbon source on Earth, is attracting increasing attention due to its advantages over oil, coal, and natural gas, including low carbon emissions, cleanliness, renewability, abundant reserves, and wide applicability, demonstrating enormous application potential. Using biomass as a raw material to prepare various chemicals, materials, and fuels is essential for building a green and sustainable chemical industry and a circular economy system. Converting the vast biomass resources into high-value bulk chemicals and connecting them with basic industrial chains such as polymers has become a new and significant approach to solving the high-value utilization of biomass. The bio-based platform compound 5-hydroxymethylfurfural (HMF) is considered a "building block" for biorefining. Due to its flexible chemical plasticity and high carbon retention rate based on sugar molecules, the catalytic extraction of high-value hydrocarbons and oxygen-containing chemicals from HMF has garnered widespread attention. Among them, high-value-added 2,5-furanic acid (FDCA) is synthesized by catalytic oxidation of HMF. Due to its good stability, it can be used as a chemical intermediate to prepare corrosion-resistant polymer plastics and pharmaceutical intermediates. It has huge market potential and is considered a basic material for realizing green chemical industry. It can effectively alleviate dependence on fossil energy and reduce carbon emissions and environmental pollution in the plastics industry.

[0003] Traditional chemical catalytic oxidation of HMF to FDCA relies on noble metal catalysts and is carried out under high temperature and pressure. Electrochemical oxidation, as a green, pollution-free, and low-cost method for synthesizing high-value oxygen-containing chemicals, has attracted widespread attention. Among these methods, the electrochemical oxidation of HMF to FDCA, conducted at room temperature and pressure in an aqueous phase, offers advantages such as mild reaction conditions, simple operation, and high energy utilization, making it highly promising. Furthermore, oxides and hydroxides of transition metals such as nickel, iron, cobalt, manganese, and copper, as well as their composites with other metals, are widely used in the electrocatalytic production of high-value-added fine chemicals and fuels due to their high catalytic activity. If transition metals such as nickel and iron could be converted into highly efficient electrocatalysts through simple techniques to directionally convert HMF to FDCA, reducing costs and increasing economic benefits, it would have enormous application potential in practical engineering. However, current research and technologies generally rely on complex synthesis methods or energy-intensive calcination to prepare catalyst materials for electrocatalytic oxidation. Chinese patent CN 111472020 A discloses a method for synthesizing layered catalysts of hydrotalcite by co-precipitation of transition metal solutions via acid-base titration. However, this method has the disadvantage of consuming a certain amount of alkali and requiring complex operation due to the need for strict control of the titration endpoint. Chinese patent CN 109837555 A discloses a method for preparing nickel-vanadium phosphide by first hydrothermally treating nickel and vanadium raw materials at 100-180℃ and then calcining them at 200-600℃. However, this method requires a complex multi-step reaction process and a long hydrothermal and calcination process, consuming a large amount of energy at high temperatures and significantly increasing production costs. In summary, there is currently no method that can prepare transition metal electrocatalysts for the electrocatalytic oxidation of biomass through a rapid, simple reaction process and low energy consumption. Currently, there is no method that uses non-precious metal compounds to prepare catalysts for the electrocatalytic oxidation of HMF using a short-process, rapid, low-energy, and low-cost approach. Therefore, the catalyst prepared by this invention has broad application prospects and significant market potential. Summary of the Invention

[0004] To address the shortcomings and deficiencies of the existing technologies, the present invention aims to provide a simple and rapid method for preparing NiFe-LDH / FeOOH catalysts for the electrocatalytic oxidation of 5-hydroxymethylfurfural. The reaction process does not require the participation of high-temperature and high-pressure gases, the method is simple and easy to implement, and it can achieve rapid and selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid under mild conditions.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for rapidly preparing a NiFe-LDH / FeOOH catalyst for the electrocatalytic oxidation of HMF includes the following steps:

[0007] (1) Pretreatment of nickel foam: Cut nickel foam into thin sheets of a certain size and ultrasonically treat them in hydrochloric acid, acetone, ethanol and ultrapure water for a certain time to obtain pure nickel foam.

[0008] (2) Prepare hydrogen peroxide solutions A with different mass fractions;

[0009] (3) Add a certain amount of iron salt to the hydrogen peroxide solution A of different volumes prepared in step (2), stir evenly, and obtain solution B;

[0010] (4) Place the pure nickel foam obtained in step (1) into solution B in step (3) and react for a certain time, then take out the nickel foam sample after reaction.

[0011] (5) After rinsing the reacted nickel foam sample obtained in step (4) several times with deionized water, place it in an oven to dry for a certain period of time to obtain the NiFe-LDH / FeOOH catalyst.

[0012] (6) Add 5-hydroxymethylfurfural dissolved in alkaline electrolyte to an H-type electrolytic cell, place a reference electrode, a counter electrode and the prepared NiFe-LDH / FeOOH catalyst, and obtain 2,5-furandicarboxylic acid at a certain potential after energizing.

[0013] 2. Preferably, the thickness of the nickel foam in step (1) is 0.5-5 mm, the size of the cut is (1-2) cm × (1-2) cm, the concentration of hydrochloric acid is 1-3 mol / L, and the hydrochloric acid, acetone, ethanol and ultrapure water are ultrasonically treated for 10-20 min respectively.

[0014] 3. Preferably, the hydrogen peroxide solution in step (2) has a mass fraction of 1% to 35%;

[0015] 4. Preferably, the iron salt mentioned in step (3) is one or more of ferrous chloride, ferrous sulfate, ferrous nitrate, ferrous phosphate, ferrous carbonate, ferric chloride, ferric nitrate, ferric sulfate, ferric phosphate, ferric carbonate, and ferrous ammonium sulfate; the iron salt content is 1-10 mmol, the stirring rate is 100-400 r / min, the stirring time is 1-10 min, and the hydrogen peroxide volume is 10-50 mL;

[0016] 5. Preferably, the reaction time of the nickel foam in solution B in step (4) is 1 to 10 minutes;

[0017] 6. Preferably, the oven temperature in step (5) is 60-80°C and the time is 12-24 hours;

[0018] 7. Preferably, the alkaline electrolyte in step (6) is a 1 mol / L KOH solution, the reference electrode is an Hg / HgO electrode, the counter electrode is a platinum wire, and the catalytic conversion potential is 1.3 to 1.6 V (vs. RHE).

[0019] The NiFe-LDH / FeOOH catalyst has a nanosheet structure with a thickness of approximately 1.4 nm.

[0020] The NiFe-LDH / FeOOH catalyst contains oxygen vacancies and metal defects.

[0021] The NiFe-LDH / FeOOH catalyst exhibits excellent electrocatalytic oxidation activity.

[0022] The NiFe-LDH / FeOOH catalyst can rapidly catalyze the oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid under mild conditions.

[0023] The NiFe-LDH / FeOOH catalyst electrocatalyzes the oxidation of 5-hydroxymethylfurfural, achieving a conversion rate of 98.40% in just 5 minutes, with a selectivity of 97.90% for 2,5-furandicarboxylic acid. Attached Figure Description

[0024] Figure 1 Electron microscope (SEM) image of NiFe-LDH / FeOOH in Example 3.

[0025] Figure 2 The image shows the X-ray diffraction (XRD) pattern of NiFe-LDH / FeOOH in Example 3.

[0026] Figure 3 The graph shows the change in the reaction of electrocatalytic oxidation of HMF to prepare FDCA in Example 3 over time.

[0027] Figure 4 The linear sweep voltammetric curves of NiFe-LDH / FeOOH in 1M KOH and after the addition of 50mM 5-hydroxymethylfurfural are shown in Example 3. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0029] Example 1

[0030] (1) Pretreatment of nickel foam: Cut nickel foam with a thickness of 0.5 mm into 1 cm × 1 cm pieces, and ultrasonically treat them for 5 min in 1 mol / L hydrochloric acid, acetone, ethanol and ultrapure water respectively to obtain pure nickel foam.

[0031] (2) Prepare a 35% (w / w) hydrogen peroxide solution A;

[0032] (3) Add 1 mmol of ferrous chloride to 10 mL of hydrogen peroxide solution A prepared in step (2), stir at a speed of 100 r / min, and stir for 1 min to obtain solution B;

[0033] (4) Place the pure nickel foam obtained in step (1) into solution B in step (3) and react for 10 min. Take out the nickel foam sample after reaction.

[0034] (5) Rinse the sample obtained in step (4) several times with deionized water, and then dry it in an oven at 60°C for 12 hours to obtain the NiFe-LDH / FeOOH catalyst.

[0035] (6) 5-Hydroxymethylfurfural (50 mmol / L) dissolved in 1 M (5 mL) KOH solution and the NiFe-LDH / FeOOH catalyst were added to an H-type electrolytic cell. An Hg / HgO reference electrode and a platinum wire electrode were placed in the cell. The reaction was carried out at 1.4 V (vs. RHE) for 5 min, with samples taken every 1 min. Finally, the substrate conversion and product yield of the reaction solution were analyzed by HPLC.

[0036] Example 2

[0037] (1) Nickel foam pretreatment: Nickel foam with a thickness of 0.5 mm was cut into thin sheets of 1 cm × 1 cm and ultrasonically treated in 2 mol / L hydrochloric acid, acetone, ethanol and ultrapure water for 15 min respectively to obtain pure nickel foam.

[0038] (2) Prepare a 20% (w / w) hydrogen peroxide solution A;

[0039] (3) Add 3 mmol of ferrous sulfate to the hydrogen peroxide solution A prepared in step (2), stir at a speed of 200 r / min for 3 min to obtain solution B;

[0040] (4) Place the pure nickel foam obtained in step (1) into solution B in step (3) and react for 5 minutes. Then take out the nickel foam sample after reaction.

[0041] (5) Rinse the sample obtained in step (4) several times with deionized water, and then dry it in an oven at 60°C for 18 hours to obtain the NiFe-LDH / FeOOH catalyst.

[0042] (6) 5-Hydroxymethylfurfural (50 mmol / L) dissolved in 1 M (5 mL) KOH solution and the NiFe-LDH / FeOOH catalyst were added to an H-type electrolytic cell. An Hg / HgO reference electrode and a platinum wire electrode were placed in the cell. The reaction was carried out at a potential of 1.4 (vs. RHE) for 5 min, with samples taken every 1 min. Finally, the substrate conversion and product yield of the reaction solution were analyzed by HPLC.

[0043] Example 3

[0044] (1) Nickel foam pretreatment: cut nickel foam with a thickness of 1 mm into 1 cm × 1 cm pieces, and ultrasonically treat them in 3 mol / L hydrochloric acid, acetone, ethanol and ultrapure water for 30 min respectively to obtain pure nickel foam.

[0045] (2) Prepare a 10% (w / w) hydrogen peroxide solution A;

[0046] (3) Add 5 mmol of ferric chloride to 20 mL of hydrogen peroxide solution A prepared in step (2), stir at a speed of 300 r / min, and stir for 5 min to obtain solution B;

[0047] (4) Place the pure nickel foam obtained in step (1) into solution B in step (3) and react for 1 min. Take out the reacted nickel foam sample.

[0048] (5) Rinse the sample obtained in step (4) several times with deionized water, and then dry it in an oven at 60°C for 24 hours to obtain the NiFe-LDH / FeOOH catalyst.

[0049] (6) 5-Hydroxymethylfurfural (50 mmol / L) dissolved in 1 M (5 mL) KOH solution and the NiFe-LDH / FeOOH catalyst were added to an H-type electrolytic cell. An Hg / HgO reference electrode and a platinum wire electrode were placed in the cell. The reaction was carried out at 1.4 V (vs. RHE) for 5 min, with samples taken every 1 min. Finally, the substrate conversion and product yield of the reaction solution were analyzed by HPLC.

[0050] Example 4

[0051] (1) Nickel foam pretreatment: cut nickel foam with a thickness of 1 mm into 1 cm × 1 cm pieces, and ultrasonically treat them for 15 min in 3 mol / L hydrochloric acid, acetone, ethanol and ultrapure water respectively to obtain pure nickel foam.

[0052] (2) Prepare a 5% (w / w) hydrogen peroxide solution A;

[0053] (3) Add 7 mmol of ferrous ammonium sulfate to 40 mL of hydrogen peroxide solution A prepared in step (2), stir at a speed of 400 r / min, and stir for 1 min to obtain solution B;

[0054] (4) Place the pure nickel foam obtained in step (1) into solution B in step (3) and react for 1 min. Take out the reacted nickel foam sample.

[0055] (5) Rinse the sample obtained in step (4) several times with deionized water, and then dry it in an oven at 60°C for 24 hours to obtain the NiFe-LDH / FeOOH catalyst.

[0056] (6) 5-Hydroxymethylfurfural (50 mmol / L) dissolved in 1 M (5 mL) KOH solution and the NiFe-LDH / FeOOH catalyst were added to an H-type electrolytic cell. An Hg / HgO reference electrode and a platinum wire electrode were placed in the cell. The reaction was carried out at 1.4 V (vs. RHE) for 5 min, with samples taken every 1 min. Finally, the substrate conversion and product yield of the reaction solution were analyzed by HPLC.

[0057] Example 5

[0058] This embodiment follows the method of Example 3, which is a method for rapidly preparing NiFe-LDH / FeOOH catalyst for electrocatalytic oxidation of HMF. The difference is that in step (2), the mass fraction of hydrogen peroxide solution is 1%, and the remaining steps are the same as in Example 3.

[0059] Example 6

[0060] This embodiment follows the method of Example 3, which is a method for rapidly preparing NiFe-LDH / FeOOH catalyst for electrocatalytic oxidation of HMF. The difference is that in step (3), the amount of ferric chloride added is 10 mmol, and the remaining steps are the same as in Example 3.

[0061] The conversion rate of 5-hydroxymethylfurfural, the yield of 2,5-furandicarboxylic acid, and the Faraday efficiency of the catalysts obtained in Examples 1-6 were tested, and the specific test results are shown in Table 1.

[0062] Table 1. Conversion rate, yield, and Faraday efficiency of NiFe-LDH / FeOOH catalyst for the electrocatalytic conversion of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid.

[0063]

[0064] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for electrocatalytic oxidation of HMF, characterized in that, At least the following steps are included: (1) Pretreatment of nickel foam: Cut nickel foam into thin sheets with a thickness of 0.5-5 mm and a size of 1-2 cm × 1-2 cm. After sonicating in 1-3 mol / L hydrochloric acid, acetone, ethanol and ultrapure water for 10-20 min respectively, pure nickel foam is obtained. (2) Prepare a hydrogen peroxide solution A with a mass fraction of 5%-35%; (3) Add the iron salt to the 10~50 mL hydrogen peroxide solution A prepared in step (2), stir at a stirring rate of 100~400 r / min for 1-10 min, and after stirring evenly, obtain solution B; (4) Place the pure nickel foam obtained in step (1) into solution B in step (3) and react for 1~10 min, then take out the nickel foam sample after reaction. (5) After rinsing the reacted nickel foam sample obtained in step (4) several times with deionized water, dry it in an oven at 60~80℃ for 12~36 h to obtain the NiFe-LDH / FeOOH catalyst; (6) Add 50 mM 5-hydroxymethylfurfural dissolved in alkaline electrolyte to an H-type electrolytic cell, place a reference electrode, and perform catalytic conversion at 1.4 V vs. RHE potential to obtain 2,5-furandicarboxylic acid by comparing the electrode with the NiFe-LDH / FeOOH catalyst prepared in step (5). The iron salt in the iron-containing solution in step (3) is one of ferrous chloride, ferrous sulfate, or ferrous ammonium sulfate.

2. The method for electrocatalytic oxidation of HMF according to claim 1, characterized in that... The alkaline electrolyte in step (6) is a 0.1~2 mol / L KOH solution, the reference electrode is Hg / HgO, and the counter electrode is a platinum wire.

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