WO2023279406A1

WO2023279406A1 - Method for preparing supported catalyst and application thereof

Info

Publication number: WO2023279406A1
Application number: PCT/CN2021/105621
Authority: WO
Inventors: 谌春林; 刘静; 朱斌; 张建
Original assignee: 中国科学院宁波材料技术与工程研究所
Priority date: 2021-07-09
Filing date: 2021-07-09
Publication date: 2023-01-12

Abstract

Provided are a method for preparing a supported catalyst and an application thereof. The preparation method comprises the following steps: carrying out spontaneous ion exchange on a substrate in a solution containing a metal salt, and performing electrochemical oxidation treatment on the product obtained by ion exchange to obtain a supported catalyst. In the preparation method, by means of spontaneous ion exchange at room temperature and subsequent electrochemical oxidation treatment, a supported catalyst is obtained. The electrochemical oxidation treatment can generate high-valence metal ions, and the reaction kinetics of an electrocatalytic production FDCA process can be enhanced.

Description

A kind of preparation method and application of supported catalyst

technical field

The application relates to a preparation method and application of a supported catalyst, belonging to the technical field of chemical industry.

Background technique

2,5‐furandicarboxylic acid (FDCA), as an important "green" platform chemical, is synthesized from various biological substrates (5‐hydroxymethylfurfural (5‐hydroxymethylfurfural, HMF), 2 ,5‐Dihydroxymethylfuran (2,5‐bis(hydroxymethyl)furan, BHMF), 5‐Hydroxymethyl‐2‐furancarboxylic acid (5‐Hydroxymethyl‐2‐furancarboxylic acid, HMFCA), 5‐formyl‐ The efficient preparation of 2‐furancarboxylic acid (5‐Formyl‐2‐furancarboxylic Acid, FFCA) and 2,5‐diformylfuran (2,5‐Furandicarbaldehyde, DFF) occupies an increasingly important position in the chemical industry. Electrocatalytic conversion has gradually become a research hotspot because it can realize the reaction of biological substrates to FDCA under mild conditions, and has the advantages of high safety, high energy utilization, and high substrate tolerance.

In the process of electrocatalytic production of FDCA, the electrocatalyst is one of the core components in the entire electrolysis device, which can reduce the overpotential caused by polarization, thereby improving the energy conversion efficiency. Therefore, it is particularly important to develop electrocatalysts with high activity and high stability. At present, the catalysts used in the electrocatalytic preparation of FDCA are mainly transition metal catalysts prepared by low-temperature calcination method, hydrothermal/solvothermal method, electrodeposition method, etc., but the common problem is that the cycle stability of these catalysts is poor. Reduce its service life. For example, Sun Yujie's research group designed Co-P/CF grown on copper foam and Ni ₂ P nanoparticle arrays grown on nickel foam for electrocatalytic oxidation of 5-hydroxymethylfurfural. 2,5‐furandicarboxylic acid, the morphology of the catalyst was completely destroyed after only three cycles (ACS Energy Lett.2016,1,386-390; Angew.Chem.Int.Ed.2016,55,9913–9917); electrolysis process The lower current density prolongs the electrolysis time and thus increases the energy consumption. For example, Yan Kai’s research group used trimetallic layered double hydroxide NiCoFe to electrocatalyze 5mM 5‐hydroxymethylfurfural. The current density before the oxygen evolution reaction at room temperature was less than 10mA cm ^‐2 , after 4 hours of reaction, the conversion rate is less than 20% (ACS Catal.2020, 10, 5179-5189); the catalyst preparation method is complicated, which increases the preparation cost, and it is difficult to scale up production. For example, the Kang research group used The two-step reaction of hydrothermal and low-temperature calcination synthesized filamentous NiCo ₂ O ₄ for the electrocatalysis of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid. The preparation is complicated and requires high temperature, which increases the preparation cost and enlarges the scale. The difficulty of production (Applied Catalysis B: Environmental 242 (2019) 85–91).

Contents of the invention

Aiming at the above-mentioned technical problems, we adopted a simple and feasible catalyst preparation method to prepare a three-dimensional self-supporting standing sheet catalyst by spontaneous ion exchange at room temperature and subsequent electrochemical oxidation treatment. Spontaneous ion exchange can complete the reaction under normal temperature and pressure. It is simple to operate, easy to control, and has very low requirements on the reaction device, so the production cost is greatly reduced, and it is easy to expand the production scale; electrochemical oxidation treatment can stabilize the electrode and can The generation of high-valence metal ions can enhance the reaction kinetics of the electrocatalytic production of FDCA; the prepared catalyst can obtain a current density of more than 100mA cm ^-2 by adding a low concentration of substrate (10mM), which greatly reduces the entire electrolysis reaction The required time only needs 0.6h to obtain 100% conversion rate and more than 95% yield; after ten cycles of electrolysis, the performance and shape of the catalyst are almost completely maintained, indicating that it has strong stability and can be greatly improved. Extend its service life.

According to one aspect of the present application, a kind of preparation method of supported catalyst is provided, and described preparation method comprises the following steps:

The substrate is subjected to spontaneous ion exchange in a solution containing a metal salt, and the product obtained by the ion exchange is subjected to electrochemical oxidation treatment to obtain the supported catalyst.

Optionally, the electrochemical oxidation treatment includes:

The product obtained by ion exchange is used as a working electrode, and electrochemical oxidation treatment is carried out in an electrolytic cell containing alkaline electrolyte.

Optionally, the alkali in the alkaline electrolyte includes at least one of KOH and NaOH.

Optionally, the alkali concentration in the alkaline electrolyte is 0.01-5M.

Optionally, the upper limit of alkali concentration in the alkaline electrolyte is selected from 0.05M, 0.1M, 0.5M, 1.5M, 1M, 2M, 3M, 4M or 5M; the lower limit is selected from 0.01M, 0.05M, 0.1M , 0.5M, 1.5M, 1M, 2M, 3M or 4M.

Optionally, the solvent in the alkaline electrolyte includes water.

Optionally, the time for the electrochemical treatment is 1-12 hours.

Among them, if the electrochemical oxidation treatment time is less than 1h, it is difficult for the electrode to reach a stable state. If the electrochemical oxidation treatment time is longer than 12h, the electrode has already reached a steady state and generates high-valent metal ions, which will only increase energy consumption.

Optionally, the time for the electrochemical treatment is 2-6 hours.

Optionally, the upper limit of the electrochemical treatment is selected from 2h, 3h, 4h, 5h, 7h, 9h or 12h; the lower limit is selected from 1h, 2h, 3h, 4h, 5h, 7h or 9h.

Optionally, the electrolytic cell containing alkaline electrolyte also includes a counter electrode;

The counter electrode is selected from at least one of graphite rod, platinum sheet, platinum wire, platinum mesh, nickel sheet, nickel wire, nickel mesh, nickel alloy,

Optionally, the electrolytic cell containing alkaline electrolyte also includes a reference electrode;

The reference electrode is selected from at least one of a mercury/mercuric oxide electrode, a silver/silver chloride electrode, and a saturated calomel electrode.

Optionally, the electrochemical oxidation treatment is selected from any one of constant current oxidation and constant voltage oxidation;

The current density of the constant current oxidation is 1-100 mA cm ^-2 .

Optionally, the upper limit of the current density of the constant current oxidation is selected from 3, 5, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100 mA cm ^-2 ; the lower limit is selected from 1, 3 , 5, 8, 10, 20, 30, 40, 50, 60, 70, 80 or 90mA cm ^‐2 .

Optionally, the substrate is a metal substrate.

Optionally, the substrate is selected from any one of nickel foam, cobalt foam, iron foam, copper foam, cobalt sheet, nickel sheet, iron sheet, and copper sheet.

Optionally, the substrate is cobalt foam or cobalt sheet.

Optionally, the metal salt is selected from any of active metal soluble salts;

The metal element in the active metal is selected from any of the transition metal elements of the 4th period and the group II metal elements

Optionally, the metal elements in the active metal are selected from any one of nickel, manganese, magnesium, iron, chromium and cobalt.

Optionally, the metal salt is selected from NiSO ₄ , MnSO ₄ , MgSO ₄ , FeSO ₄ , CoSO ₄ , Ni(NO ₃ ) ₂ , Mn(NO ₃ ) ₂ , Mg(NO ₃ ) ₂ , Co(NO ₃ ) any of ₂ .

Optionally, the solvent in the metal salt-containing solution includes water.

Optionally, the concentration of the solution containing the metal salt is 1-1000 mM.

Optionally, the upper limit of the concentration of the solution containing the metal salt is selected from 5mM, 10mM, 100mM, 200mM, 300mM, 400mM, 500mM, 600mM, 700mM, 800mM or 1000mM, and the lower limit is selected from 1mM, 5mM, 10mM, 100mM, 200mM , 300 mM, 400 mM, 500 mM, 600 mM, 700 mM or 800 mM.

Optionally, the ion exchange time is 0.5-72h.

Optionally, the upper limit of the ion exchange time is selected from 1h, 6h, 12h, 18h, 24h, 30h, 36h, 42h, 48h or 72h; the lower limit is selected from 0.5h, 1h, 6h, 12h, 18h, 24h, 30h , 36h, 42h or 48h.

According to another aspect of the present application, a supported catalyst is provided, and the supported catalyst is prepared according to any one of the preparation methods described above.

Optionally, the supported catalyst includes a substrate and an active component;

The active component is loaded on the substrate;

The supported catalyst is a three-dimensional self-supporting structure with standing nanosheets.

Optionally, the active component is grown in situ on the substrate.

Optionally, the metal elements in the active component include metal elements I and metal elements II;

The metal element I is selected from any one of the metal elements in the substrate;

The metal element II is selected from any one of the metal elements in active metals;

The active component is a metal hydroxide, wherein the metal element I and the metal element II are the same metal element;

or

The active component is a layered double metal hydroxide.

Optionally, the metal element II is selected from any one of nickel, manganese, magnesium, iron, chromium and cobalt.

According to another aspect of the present application, a method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds is provided, and the method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds adopts a catalyst as a supported catalyst;

The supported catalyst includes at least one of the supported catalyst prepared according to the preparation method described in any one of the above and the supported catalyst described in any one of the above.

Optionally, the furan compounds include 2,5-furandimethanol, 5-hydroxymethylfurfural, 5-hydroxymethyl-2-furoic acid, 5-formyl-2-furoic acid, 2,5- At least one of diformyl furan.

Optionally, the method includes:

In the electrolytic cell I, the electrolytic solution I containing furan compounds is catalyzed and oxidized to obtain 2,5-furandicarboxylic acid;

Wherein, the supported catalyst is used as an anode.

Optionally, the electrolyte I also includes an alkaline substance I and a solvent I;

The basic substance I includes KOH;

The solvent I includes water.

Optionally, in the electrolyte I, the concentration I of the furan compound is 1 mM˜1000 mM.

Optionally, the upper limit of the concentration I is selected from 10mM, 50mM, 100mM, 200mM, 300mM, 400mM, 500mM, 600mM, 800mM or 1000mM; 600mM or 800mM.

Optionally, in the electrolyte I, the concentration of the alkaline substance I is 0.01M-5M.

Optionally, the upper limit of the concentration of the alkaline substance I is selected from 0.1, 1, 2, 3, 4, 5M, and the lower limit is selected from 0.01, 0.1, 1, 2, 3, 4M.

Optionally, the catalytic oxidation voltage is 1V-2.0V.

Where the voltage is lower than 1V, it is not enough to catalyze the oxidation of furan compounds to prepare 2,5-furandicarboxylic acid, and the voltage is higher than 2V, the oxygen evolution reaction is violent, and the yield of 2,5-furandicarboxylic acid is extremely low.

Optionally, the catalytic oxidation voltage is 1.2V-1.6V.

Optionally, the upper limit of the voltage is selected from 1.067, 1.3, 1.5, 1.8 or 2V, and the lower limit of the voltage is selected from 1, 1.067, 1.3, 1.5 or 1.8V

Optionally, the catalytic oxidation time I is 0.1h-12h.

Among them, if the catalytic oxidation time is less than 0.1h, the reaction is incomplete, and the yield of 2,5-furandicarboxylic acid is extremely low. If the catalytic oxidation time is higher than 12h, the reaction has already ended, which will only increase energy consumption.

Optionally, the catalytic oxidation time I is 0.5h-6h.

Optionally, the upper limit of the catalytic oxidation time I is selected from 0.5h, 1h, 2h, 3h, 4h, 5h, 7h, 9h or 12h; the lower limit is selected from 0.1h, 0.5h, 1h, 2h, 3h, 4h, 5h, 7h or 9h.

This application provides a method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds. The method uses a metal base to stand a sheet-like three-dimensional self-supporting electrocatalyst, and uses its sheet structure to expose more active sites, while the three-dimensional The self-supporting monolithic structure enhances the stability of the catalyst, which can increase the yield and stability of the reaction.

The standing sheet-like three-dimensional self-supporting electrocatalyzed furan compound-based 2,5-furandicarboxylic acid catalyst used in this application is prepared in situ on a metal-based framework. The specific preparation steps include: pretreatment of the metal substrate; preparation of ion exchange solution and electrolyte solution; placing the treated metal substrate in the ion exchange solution at room temperature for several hours; Rinse with ion water, dry under natural conditions, and electrochemical oxidation treatment. The standing sheet catalyst utilized in this application can utilize its sheet structure to expose more active sites. The three-dimensional self-supporting overall structure enhances the stability of the catalyst and avoids the use of polymer binders that are not conducive to conductivity. At the same time, the room temperature The preparation method of the catalyst by spontaneous ion exchange reaction is simple and easy for large-scale production.

The present invention aims at the problems existing in the existing electrocatalytic preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural, and provides a highly efficient foam cobalt-based electrocatalytic preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural. Preparation method of formic acid catalyst. The preparation method has the advantages of simple process flow, easy operation, and is expected to be mass-produced. The prepared catalyst has a nanosheet structure and is loaded on foamed cobalt in situ. The stable structure of the macroporous cobalt foam self-grown three-dimensional self-supporting nanosheets improves the electron transfer rate and fully exposes the active sites of the catalyst.

In one aspect of the present invention, a method for preparing a standing sheet-like three-dimensional self-supporting catalyst is proposed, the method comprising the steps of:

(1) pretreatment of foamed cobalt CF;

(2) preparation of ion exchange solution and electrolyte solution;

(3) Preparation of standing sheet catalyst.

Optionally, in step (1), the purchased commercial cobalt foam is cut into strips of 0.5cm*3cm, ultrasonically cleaned in acetone and absolute ethanol for 5 minutes, and dried naturally in the air for later use.

The spontaneous ion exchange method is a method for preparing catalysts under mild conditions. The standing sheet-like catalyst prepared by it can use its sheet structure to expose more active sites, and its three-dimensional self-supporting overall structure enhances the stability of the catalyst. , at the same time, the preparation method of the catalyst by the spontaneous ion exchange method is simple, easy to scale up production, and has broad prospects for industrial use.

Optionally, in step (2), the preparation of ion exchange solution: take by weighing the solid containing divalent metal salt solution dissolved in deionized water to prepare ion exchange solution; the preparation of electrolyte solution: take by weighing alkaline solid dissolved in super Prepare an alkaline electrolyte solution in pure water.

In the present application, there is no special limitation on the divalent metal salt solution and its concentration. In order to prepare a three-dimensional self-supporting catalyst with better performance, preferably, the divalent metal salt solution is selected from NiSO ₄ , MnSO ₄ , MgSO ₄ FeSO ₄ , CoSO ₄ , Ni(NO ₃ ) ₂ , Mn(NO ₃ ) ₂ , Mg(NO ₃ ) ₂ , Co(NO ₃ ) ₂ at least one.

Optionally, the concentration of the divalent metal salt solution is 1 mM˜1000 mM.

Specifically, the upper limit of the concentration of the divalent metal salt solution is independently selected from 500mM, 600mM, 700mM, 800mM, and 1000mM; the lower limit of the concentration of the divalent metal salt solution is independently selected from 1mM, 5mM, 10mM, 100mM, 200mM, 300mM, and 400mM.

In the present application, the alkaline electrolyte solution is not particularly limited. In order to prepare a three-dimensional self-supporting catalyst with better performance, preferably, the alkaline electrolyte solution is at least one of potassium hydroxide solution and sodium hydroxide solution.

Optionally, the concentration of the alkaline electrolyte solution is 0.01M-5M.

Specifically, the upper limit of the concentration of the alkaline electrolyte solution is independently selected from 0.05M, 0.1M, 0.5M, 1.5M, 1M, 2M, 3M, 4M or 5M; the lower limit of the concentration of the alkaline electrolyte solution is independently selected from 0.01M, 0.05M, 0.1 M, 0.5M, 1.5M, 1M, 2M, 3M or 4M.

Optionally, in step (3), the preparation of standing sheet catalyst at least comprises the following steps:

(3‐1) Spontaneous ion exchange reaction: place the treated cobalt foam in an ion exchange solution at room temperature for several hours; after the reaction is complete, take out the cobalt foam loaded with active substances, rinse with deionized water, and dry naturally in the air.

(3‐2) Electrochemical oxidation treatment: The foamed cobalt after (3‐1) cleaning was subjected to electrochemical oxidation treatment in a three-electrode system of alkaline electrolyte solution to obtain a three-dimensional self-supporting standing sheet catalyst.

Optionally, in step (3-1), the storage time at room temperature is 0.5h to 72h.

Specifically, the upper limit of storage time at room temperature is independently selected from 1h, 6h, 12h, 18h, 24h, 30h, 36h, 42h, 48h or 72h; the lower limit of storage time at room temperature is independently selected from 0.5h, 1h, 6h, 12h, 18h, 24h, 30h, 36h, 42h or 48h.

Optionally, in step (3-2), in the three-electrode system, the working electrode is cobalt foam after spontaneous ion exchange reaction, and the counter electrode is selected from graphite rod, platinum sheet, platinum wire, platinum mesh, nickel sheet, nickel At least one of wire, nickel mesh, and nickel alloy, and the reference electrode is at least one of mercury/mercury oxide electrode, silver/silver chloride electrode, and saturated calomel electrode.

Optionally, in step (3-2), the electrochemical oxidation time is 1h-12h.

Specifically, the upper limit of electrochemical oxidation time is independently selected from 2h, 3h, 4h, 5h, 7h, 9h or 12h; the lower limit of electrochemical oxidation time is independently selected from 1h, 2h, 3h, 4h, 5h, 7h or 9h.

In another aspect of the present invention, a method for preparing 2,5-furandicarboxylic acid by electrocatalyzing 5-hydroxymethylfurfural is proposed, the method at least includes: in the electrolytic cell, the catalyst is used as the anode, and the electrolyte is catalyzed and oxidized , the reaction gives 2,5‐furandicarboxylic acid.

Optionally, the electrolytic cell is a two-electrode electrolytic cell or a three-electrode electrolytic cell; the catalyst is selected from at least one of the standing sheet catalysts prepared by the method described above; the electrolyte contains 5-hydroxy Aqueous solution of methylfurfural.

Optionally, the concentration of 5-hydroxymethylfurfural is 1 mM-500 mM.

Specifically, the upper limit of the concentration of 5-hydroxymethylfurfural is independently selected from 10mM, 50mM, 100mM, 200mM, 300mM, 400mM or 500mM; the lower limit of the concentration of 5-hydroxymethylfurfural is independently selected from 1mM, 5mM, 10mM, 100mM, 200mM, 300mM, 400mM.

Optionally, in the electrolytic cell, the voltage of the electrolytic cell is 1.067V-2.0V.

Optionally, the minimum voltage of the three-electrode electrolytic cell is 0.5V, and the minimum voltage of the two-electrode electrolytic cell is 0.5V.

The present invention prepares nanosheets grown on cobalt foam in situ by a simple spontaneous ion exchange method as a catalyst for electrocatalyzing 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. Compared with noble metal catalysts, it reduces Catalyst cost.

The standing sheet catalyst prepared by the method can utilize its sheet structure to expose more active sites, and at the same time, the three-dimensional self-supporting integral structure enhances the stability of the catalyst.

The preparation method of the catalyst by the spontaneous ion exchange method is simple, easy to operate, and easy to scale up production.

Electrochemical oxidation treatment can generate high-valence metals, and the prepared catalyst has high electrocatalytic 5‐hydroxymethylfurfural oxidation performance.

In this application, both room temperature and natural drying temperature are 25°C.

In this application, the relevant English or abbreviated descriptions are as follows:

LDH: layered double metal hydroxide;

CF: cobalt foam.

The beneficial effect that this application can produce comprises:

(1) A simple and feasible catalyst preparation method provided by this application prepares a three-dimensional self-supporting standing sheet catalyst by spontaneous ion exchange at room temperature and subsequent electrochemical oxidation treatment. Complete, the catalyst preparation method with extremely low requirements on the reaction device, simple operation and easy control greatly reduces the production cost, and at the same time, it is easy to scale up the production.

(2) A simple and feasible catalyst preparation method provided by this application prepares a three-dimensional self-supporting standing sheet catalyst by spontaneous ion exchange at room temperature and subsequent electrochemical oxidation treatment. Electrochemical oxidation treatment can generate high-valence Metal ions can enhance the reaction kinetics of the electrocatalytic production of FDCA.

(3) A simple and feasible catalyst preparation method provided by this application prepares a three-dimensional self-supporting standing sheet catalyst by spontaneous ion exchange at room temperature and subsequent electrochemical oxidation treatment, which is used as an anode electrolysis furan substrate To generate FDCA, a current density of more than 100mA cm ^‐2 can be obtained by adding a low concentration of substrate, which greatly reduces the time required for the entire electrolysis reaction. It only takes 0.6h to obtain 100% conversion rate and more than 95% yield. Rate.

(4) A simple and feasible catalyst preparation method provided by this application prepares a three-dimensional self-supporting standing sheet catalyst by spontaneous ion exchange at room temperature and subsequent electrochemical oxidation treatment. After ten cycles of electrolysis, the performance of the catalyst is The shape and shape are almost completely maintained, indicating that it has strong stability and can greatly extend its service life.

Description of drawings

Fig. 1 is the scanning electron micrograph of the catalyst (sample 1) that makes in the embodiment 1 of the present invention; Wherein, (a) scale bar is 50 μ m, (b) scale bar is 10 μ m, (c) scale bar is 500 nm;

Figure 2 is the X-ray photoelectron spectrum of the precursor (before electrochemical oxidation treatment, corresponding to the activation in the picture) and sample 3 (after electrochemical oxidation treatment, corresponding to the activation in the picture) prepared in Example 3 of the present invention The fine spectrum of Ni and Co in the middle, wherein (a) is the fine spectrum of Ni, (b) is the fine spectrum of Co;

Fig. 3 is the anode current density-potential figure of different electrolytic solutions in the three-electrode system that makes sample 3 and substrate foam cobalt respectively as anode catalyst in the embodiment 3 of the present invention;

Fig. 4 is that sample 3 is obtained in the embodiment of the present invention 3 and is used as the three-electrode system of anode catalyst conversion rate of raw material BHMF or anode product yield-charge diagram;

Fig. 5 is the potential-time diagram when the current density is 10mA cm ^-2 in the three-electrode system in which sample 3 is prepared as an anode catalyst in Example 3 of the present invention;

Fig. 6 is a percentage diagram of BHMF conversion rate, FDCA yield, Faradaic efficiency and carbon balance in ten cycle electrolysis of BHMF in sample 3 prepared in Example 3 as an anode catalyst in a three-electrode system.

detailed description

The present application is described in detail below in conjunction with the examples, but the present application is not limited to these examples.

Unless otherwise specified, the experimental methods used in the examples of the present application are conventional methods unless otherwise specified; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources. The instruments used in the following examples, unless otherwise specified, are used with parameters recommended by the manufacturer.

The instrument and parameter that sample analysis adopts in the embodiment are as follows:

SEM analysis was performed using a HITACHI S‐4800 scanning electron microscope at 8.0 kV.

Using Kratos AXIS ULTRA ^DLD equipment to carry out X-ray photoelectron spectroscopy analysis with Al as the target.

Electrochemical oxidation and catalytic reactions were carried out using a CS 150H electrochemical workstation.

Example 1

(1) Ultrasonic cleaning of purchased commercial cobalt foam in acetone for 10 min, then ultrasonic cleaning in absolute ethanol for 10 min, and drying.

(2) Prepare a 1mM NiSO ₄ aqueous solution, immerse the foamed cobalt treated in step (1) into the above 1mM NiSO ₄ aqueous solution, take it out after 12h, rinse and dry.

(3) In the electrolytic cell containing 1M KOH electrolyte, the precursor prepared in step (2) is used as the working electrode, the carbon rod is used as the counter electrode, and mercury/mercury oxide is used as the reference electrode, and a three-electrode system is assembled, wherein, The area of the working electrode immersed in the electrolyte is 0.5cm ^‐2 . The electrochemical oxidation treatment was carried out for 2 hours at a current density of 10mA cm ^- 2, and the obtained catalyst was a NiCo LDH/CF catalyst containing high-valence (3 ⁺ ) Ni and Co, which was designated as sample 1.

(4) Add 5 mL of 1M KOH to the three-electrode system assembled in step (3) containing the electrochemically oxidized catalyst (sample 1) as the working electrode, the carbon rod as the counter electrode, and the mercury/mercuric oxide as the reference electrode +10mM HMF electrolyte, the voltage is set to 1.475V, the electrocatalytic oxidation of 5‐hydroxymethylfurfural to 2,5‐furandicarboxylic acid occurs on the working electrode, and the reaction of water reduction to _H2 occurs on the counter electrode.

In step (4), using sample 1 as a standing sheet catalyst, 100% HMF conversion and about 90% FDCA yield can be obtained when the theoretical charge reaches 28.9C.

Example 2

(1) The purchased commercial cobalt foam was ultrasonically cleaned in acetone for 10min, then ultrasonically cleaned in absolute ethanol for 10min, and dried.

(2) Prepare a 10mM NiSO ₄ aqueous solution, immerse the foamed cobalt treated in step (1) into the above 10mM NiSO ₄ aqueous solution, take it out after 24h, rinse and dry.

(3) In the electrolytic cell containing 1M KOH electrolyte, the precursor prepared in step (2) is used as the working electrode, the carbon rod is used as the counter electrode, and mercury/mercury oxide is used as the reference electrode, and a three-electrode system is assembled, wherein, The area of the working electrode immersed in the electrolyte is 0.5cm ^‐2 . The electrochemical oxidation treatment was carried out for 5 hours at a current density of 10mA cm ^-2 , and the obtained catalyst was a NiCo LDH/CF catalyst containing high-valence Ni and Co, which was designated as sample 2.

(4) Add 5 mL of 1M KOH to the three-electrode system assembled in step (3) containing the electrochemically oxidized catalyst (sample 3) as the working electrode, the carbon rod as the counter electrode, and the mercury/mercuric oxide as the reference electrode +10mM HMF electrolyte, the voltage is set to 1.485V, the reaction of electrocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid occurs on the working electrode, and the reaction of water reduction to _H2 occurs on the counter electrode.

In step (4), when the sample 2 is used as a standing sheet catalyst, a 100% HMF conversion and a 90.7% FDCA yield can be obtained when the theoretical charge reaches 28.9C.

Example 3

(3) In the electrolytic cell containing 1M KOH electrolyte, the precursor prepared in step (2) is used as the working electrode, the carbon rod is used as the counter electrode, and mercury/mercury oxide is used as the reference electrode, and a three-electrode system is assembled, wherein, The area of the working electrode immersed in the electrolyte is 0.5cm ^‐2 . The electrochemical oxidation treatment was carried out for 5 h at a current density of 10 mA cm ^-2 , and the obtained catalyst was a NiCo LDH/CF catalyst containing high-valence Ni and Co, which was designated as sample 3.

(4) Add 5 mL of 1M KOH to the three-electrode system assembled in step (3) containing the electrochemically oxidized catalyst (sample 3) as the working electrode, the carbon rod as the counter electrode, and the mercury/mercury oxide as the reference electrode +10mM BHMF electrolyte, the voltage is set to 1.4V, the reaction of electrocatalytic oxidation of 2,5-furandimethanol to 2,5-furandicarboxylic acid occurs on the working electrode, and the reaction of water reduction to _H2 occurs on the counter electrode . The test results are shown in Figure 4.

In step (4), when the sample 3 is used as a standing sheet catalyst, a 100% conversion of BHMF and a yield of 99.6% of FDCA can be obtained when the theoretical charge reaches 38.6C.

Example 4

(2) Prepare a 20mM NiSO ₄ aqueous solution, immerse the foamed cobalt treated in step (1) into the 20mM NiSO ₄ aqueous solution, take it out after 12 hours, rinse and dry.

(3) In the electrolytic cell containing 1M KOH electrolyte, the precursor prepared in step (2) is used as the working electrode, the carbon rod is used as the counter electrode, and mercury/mercury oxide is used as the reference electrode, and a three-electrode system is assembled, wherein, The area of the working electrode immersed in the electrolyte is 0.5cm ^‐2 . The electrochemical oxidation treatment was carried out at a current density of 10 mA cm ^-2 for 5 h, and the obtained catalyst was a NiCo LDH/CF catalyst containing high-valence Ni and Co, which was designated as sample 4.

(4) Add 5 mL of 1M KOH to the three-electrode system assembled in step (3) containing the electrochemically oxidized catalyst (sample 4) as the working electrode, the carbon rod as the counter electrode, and the mercury/mercury oxide as the reference electrode +100mM BHMF electrolyte, the voltage is set to 1.45V, the reaction of electrocatalytic oxidation of 2,5-furandimethanol to 2,5-furandicarboxylic acid occurs on the working electrode, and the reaction of water reduction to _H2 occurs on the counter electrode .

In step (4), using sample 4 as a standing sheet catalyst, 100% conversion of BHMF and 92% yield of FDCA can be obtained when the theoretical charge reaches 386C.

Example 5

(2) Prepare a 5mM NiSO ₄ aqueous solution, immerse the foamed cobalt treated in step (1) into the above 5mM NiSO ₄ aqueous solution, take it out after 24h, rinse and dry.

(3) In the electrolytic cell containing 1M KOH electrolyte, the precursor prepared in step (2) is used as the working electrode, the carbon rod is used as the counter electrode, and mercury/mercury oxide is used as the reference electrode, and a three-electrode system is assembled, wherein, The area of the working electrode immersed in the electrolyte is 0.5cm ^‐2 . The electrochemical oxidation treatment was carried out for 5 hours at a current density of 10mA cm ^-2 , and the obtained catalyst was a NiCo LDH/CF catalyst containing high-valence Ni and Co, which was designated as sample 5.

(4) Add 5 mL of 1M KOH to the three-electrode system assembled in step (3) containing the electrochemically oxidized catalyst (sample 5) as the working electrode, the carbon rod as the counter electrode, and the mercury/mercuric oxide as the reference electrode +100mM HMF electrolyte, the voltage is set to 1.45V, the electrocatalytic oxidation of 5‐hydroxymethylfurfural to 2,5‐furandicarboxylic acid occurs on the working electrode, and the reaction of water reduction to _H2 occurs on the counter electrode.

In step (4), using sample 5 as a standing sheet catalyst, 100% HMF conversion and 89% FDCA yield can be obtained when the theoretical charge reaches 289C.

Example 6

(2) Prepare a 10mM NiSO ₄ aqueous solution, immerse the foamed cobalt treated in step (1) into the 10mM NiSO ₄ aqueous solution, take it out after 48h, rinse and dry.

(3) In the electrolytic cell containing 1M KOH electrolyte, the precursor prepared in step (2) is used as the working electrode, the carbon rod is used as the counter electrode, and mercury/mercury oxide is used as the reference electrode, and a three-electrode system is assembled, wherein, The area of the working electrode immersed in the electrolyte is 0.5cm ^‐2 . The electrochemical oxidation treatment was carried out for 2 hours at a current density of 10mA cm ^- 2, and the obtained catalyst was a NiCo LDH/CF catalyst containing high-valence Ni and Co, which was designated as sample 6.

(4) Add 5 mL of 1M KOH to the three-electrode system assembled in step (3) containing the electrochemically oxidized catalyst (sample 6) as the working electrode, the carbon rod as the counter electrode, and the mercury/mercuric oxide as the reference electrode +10mM BHMF electrolyte, the voltage is set to 1.4V, the reaction of electrocatalytic oxidation of 2,5-furandimethanol to 2,5-furandicarboxylic acid occurs on the working electrode, and the reaction of water reduction to _H2 occurs on the counter electrode .

In step (4), using sample 6 as a standing sheet catalyst, 100% BHMF conversion and 95.4% FDCA yield can be obtained when the theoretical charge reaches 38.6C.

Example 7 Detection and analysis of samples 1 to 6

Fig. 1 is the scanning electron micrograph of the NiCo LDH catalyst (sample 1) that makes in embodiment 1, and wherein (a) scale bar is 50 μ m, and (b) scale bar is 10 μ m, and (c) scale bar is 500 nm. It can be seen from the figure that the standing sheet catalyst was successfully prepared.

Figure 2 shows the precursors prepared in Example 3 (before electrochemical oxidation treatment, corresponding to "before activation" in the picture) and sample 3 (after electrochemical oxidation treatment, corresponding to "after activation" in the picture) X-ray photoelectron The fine spectrum of Ni and Co in the energy spectrum, where (a) is the fine spectrum of Ni, and (b) is the fine spectrum of Co. It can be seen from the figure that after electrochemical oxidation treatment, Ni ³⁺ increases, Ni ²⁺ decreases, and Co ²⁺ becomes Co ³⁺ , indicating that more high-valence metal ions can be generated after 5h electrochemical oxidation treatment , so that the reaction kinetics of the electrocatalytic preparation of FDCA from furan substrates can be enhanced when the catalyst is used as the anode.

Fig. 3 is that sample 3 (corresponding to "catalyst" in the picture) and substrate foam cobalt (corresponding to "pure cobalt foam" in the picture) are prepared as different electrolytes in the three-electrode system of the anode catalyst in Example 3 (electrolyte An aqueous solution of 1M KOH (corresponding to "No BHMF" in the picture) or an aqueous solution of 1M KOH+10mM BHMF (corresponding to "10mM BHMF" in the picture) or an aqueous solution of 1M KOH+100mM BHMF (corresponding to "100mM BHMF" in the picture) BHMF")) anodic current density-potential diagram (test conditions: sweep speed 5mVs ^-1 , stirring speed: 600rpm), it can be seen from Figure 3 that compared with the base foam cobalt, sample 3 has an average value under the same potential before and after adding BHMF. Have higher current density, or need smaller electric potential to reach same current density, this shows that sample 3 has better catalytic performance compared with base foam cobalt; Can see that when catalyst is used as anode simultaneously, add the BHMF of low concentration ( 10mM) can obtain a very large current density, indicating that the catalyst can be used as an anode to electrolyze furan substrates to generate FDCA, which can greatly shorten the entire electrolysis time and reduce energy consumption.

Fig. 4 is that sample 3 is obtained in embodiment 3 as the three-electrode system of anode catalyst conversion rate of raw material BHMF or anode product yield-charge diagram, as can be seen from Fig. 4, the NiCo LDH (sample 3) of preparation is as anode catalyst In the three-electrode system, the electrocatalytic oxidation of BHMF to prepare FDCA, the conversion rate of BHMF can reach 100%, and the yield of FDCA can reach 99.6% (test conditions: room temperature; electrolyte: 1M KOH+10mM BHMF; electrolytic potential: 1.4V vs. RHE), It shows that the catalyst has very good electrocatalytic BHMF oxidation performance as an anode. At the same time, it can be seen from Figure 4 that in the process of preparing FDCA by electrocatalytic oxidation of BHMF, the intermediate products are HMF, HMFCA and FFCA, and no DFF is observed, indicating that the catalyst is used as an anode electrocatalytic oxidation of BHMF to prepare FDCA. The reaction process of BHMF→HMF→HMFCA→FFCA→FDCA.

Figure 5 is a potential-time diagram (test conditions: room temperature; electrolyte: 1M KOH) when the current density is 10mA cm ^-2 in the three-electrode system obtained in Example 3 as the anode catalyst, as can be seen from the figure , After 24h, the potential only changed by about 13mV, indicating that the prepared NiCo LDH (sample 3) had better stability as an anode catalyst.

Fig. 6 is the sample 3 of making in embodiment 3 as anode catalyst three-electrode system in ten cycle electrolysis BHMF (test condition: room temperature; Electrolyte: 1M KOH+10mM BHMF; Electrolysis potential: 1.4V vs.RHE) in BHMF conversion It can be seen from the figure that after ten cycles of electrolysis, the BHMF conversion rate, FDCA yield, Faradaic efficiency and carbon balance are 100%, 95.7%, and 94.8% respectively. , 95.7%, indicating that the catalyst has strong cycle stability.

Embodiment 8～9

The difference between the steps of Examples 8-9 and Example 1 is only as shown in Table 1 below

Table 1 The difference between embodiment 8～9 and embodiment 1

The above are only a few embodiments of the application, and do not limit the application in any form. Although the application is disclosed as above with preferred embodiments, it is not intended to limit the application. Any skilled person familiar with this field, Without departing from the scope of the technical solution of the present application, any changes or modifications made using the technical content disclosed above are equivalent to equivalent implementation cases, and all belong to the scope of the technical solution.

Claims

A kind of preparation method of supported catalyst, it is characterized in that, described preparation method comprises the following steps:

The substrate is subjected to spontaneous ion exchange in a solution containing a metal salt, and the product obtained by the ion exchange is subjected to electrochemical oxidation treatment to obtain the supported catalyst.
The preparation method according to claim 1, wherein the electrochemical oxidation treatment comprises:

The product obtained by ion exchange is used as a working electrode, and electrochemical oxidation treatment is carried out in an electrolytic cell containing alkaline electrolyte.
The preparation method according to claim 2, wherein the alkali in the alkaline electrolyte comprises at least one of KOH and NaOH.
The preparation method according to claim 2, characterized in that the alkali concentration in the alkaline electrolyte is 0.01-5M.
The preparation method according to claim 1, characterized in that, the time of the electrochemical oxidation treatment is 1-12 hours.
The preparation method according to claim 1, wherein the electrochemical oxidation treatment is selected from any one of constant current oxidation and constant voltage oxidation;

The current density of the constant current oxidation is 1-100 mA cm -2 .
The preparation method according to claim 1, wherein the substrate is selected from any one of nickel foam, cobalt foam, iron foam, copper foam, cobalt sheet, nickel sheet, iron sheet, and copper sheet.
The preparation method according to claim 1, wherein the metal salt is selected from any one of active metal soluble salts;

The metal element in the active metal is selected from any one of transition metal elements of the fourth period and group II metal elements.
The preparation method according to claim 8, characterized in that, the metal element in the active metal is selected from any one of nickel element, manganese element, magnesium element, iron element, chromium element and cobalt element.
A supported catalyst, characterized in that the supported catalyst is prepared according to the preparation method described in any one of claims 1-9.
The supported catalyst according to claim 10, characterized in that, the supported catalyst comprises a substrate and an active component;

The active component is loaded on the substrate;

The supported catalyst is a three-dimensional self-supporting structure with standing nanosheets.
The supported catalyst according to claim 10, wherein the active component is grown in situ on the substrate.
The supported catalyst according to claim 10, wherein the metal element in the active component comprises metal element I and metal element II;

The metal element I is selected from any one of the metal elements in the substrate;

The metal element II is selected from any one of the metal elements in active metals;

The active component is a metal hydroxide, wherein the metal element I and the metal element II are the same metal element;

or

The active component is a layered double metal hydroxide.
A method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds, characterized in that, the method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds uses a catalyst as a supported catalyst;

The supported catalyst includes at least one of the supported catalyst prepared according to the preparation method described in any one of claims 1-9 and the supported catalyst described in any one of claims 10-13.
Electrocatalytic furan compound according to claim 14 prepares the method for 2,5-furandicarboxylic acid, it is characterized in that, described method comprises:

In the electrolytic cell I, the electrolytic solution I containing furan compounds is catalyzed and oxidized to obtain 2,5-furandicarboxylic acid;

Wherein, the supported catalyst is used as an anode.
The method for preparing 2,5-furandicarboxylic acid by electrocatalytic furan compound according to claim 15, is characterized in that, described electrolytic solution I also comprises alkaline substance I and solvent I;

The basic substance I includes KOH;

The solvent I includes water.
The method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds according to claim 15, characterized in that, in the electrolyte I, the concentration I of the furan compounds is 1 mM to 1000 mM.
The method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds according to claim 15, characterized in that the voltage of the catalytic oxidation is 1V-2.0V.
The method for preparing 2,5-furandicarboxylic acid by electrocatalyzing furan compounds according to claim 15, wherein the time I of the catalytic oxidation is 0.1h-12h.