A cobalt-based electrocatalyst, a preparation method and application thereof

Abstract

This invention provides a cobalt-based electrocatalyst, its preparation method, and its application, belonging to the field of electrochemical catalysis technology. The cobalt-based electrocatalyst provided by this invention operates at a current of 100 mA·cm⁻¹. ‑2 With a voltage as low as 1.35V (Vvs. RHE), the OER activity can be effectively suppressed. It exhibits excellent electron conduction efficiency, enabling efficient electrocatalytic oxidation of HMF to FDCA under low potential and high current density conditions. It also demonstrates high catalytic activity for HMFOR, allowing the reaction to occur with lower energy consumption and improving energy conversion efficiency. Using the cobalt-based electrocatalyst provided by this invention to electrocatalyze the preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural, the conversion rate of 5-hydroxymethylfurfural reached 100%, and the yield of 2,5-furandicarboxylic acid reached 99.9%, indicating that the cobalt-based electrocatalyst provided by this invention has high electrocatalytic conversion and yield, strong stability, and fast response speed.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical catalysis technology, specifically relating to a cobalt-based electrocatalyst, its preparation method, and its application. Background Technology

[0002] 5-Hydroxymethylfurfural (HMF) is a representative platform molecule derived from C6 biomass. HMF contains highly reactive hydroxyl and carbonyl groups, allowing it to be converted into polymer precursors with diverse structures and properties. 2,5-Furandicarboxylic acid (FDCA) is a symmetrical diacid compound at the 2,5-position, formed by the selective oxidation of HMF. Its structure is highly similar to petrochemical-based terephthalic acid and can be used as a substitute for HMF in polymerization with ethylene glycol to produce ethylene furanate. This ethylene furanate is used to manufacture renewable plastic fibers, films, and other products, showing broad application prospects and high economic value. The reaction route for the electrocatalytic preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural is shown in Formula I:

[0003] Formula I.

[0004] Currently, electrocatalysts for the electrocatalytic production of FDCA from HMF mainly include noble metal, non-noble metal, and non-metal catalysts. Developing highly efficient electrocatalysts with low potential and high current density is crucial for the large-scale production of H2 and other high-value-added chemicals from biomass. For example, existing technology (Weiran Zheng, et al. Electrochemical Instability of Metal-Organic Frameworks: In Situ Spectroelectrochemical Investigation of the Real Active Sites[J] ACS Catalysis 2020, 10 (1): 81-92) discloses a cobalt-based catalyst Co(OH)2@ZIF-67, which achieves high efficiency at a current of 100 mA·cm⁻¹. -2 The voltage is 1.64 V (V) vs However, in the HMF electrochemical oxidation reaction using water as the reaction medium, the water oxidation reaction (Oxygen Evolution Reaction, abbreviated as OER) and the HMF oxidation reaction (5-Hydroxymethylfurfural Oxidation Reaction, abbreviated as HMFOR) are competing reactions, and the above catalysts have low catalytic activity for HMFOR. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a cobalt-based electrocatalyst, its preparation method and application. The cobalt-based electrocatalyst provided by this invention has high catalytic activity and high energy conversion efficiency for HMFOR.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a cobalt-based electrocatalyst, comprising an acid-treated substrate and an active component deposited on the acid-treated substrate;

[0008] The active components include Co(OH)₂ nanosheets and / or Co₇Ln₃(OH)₂. x Nanosheets; the Co7Ln3(OH) x Ln is one or more of La, Ce and Pr, and x is 20~33; the acid-treated substrate includes acid-treated carbon materials and / or acid-treated foam metal.

[0009] Preferably, the Co(OH)₂ nanosheets and Co₇Ln₃(OH)₂ nanosheets... x The thickness of the nanosheets is independently 0.5~2 nm.

[0010] Preferably, the acid-treated carbon material is made of carbon paper and / or carbon cloth; the acid-treated foam metal is made of one or more of foam copper, foam iron and foam nickel.

[0011] Preferably, the acid-treated substrate is a hydrochloric acid-treated substrate.

[0012] This invention provides a method for preparing the cobalt-based electrocatalyst described above, comprising the following steps:

[0013] Using an acid-treated substrate as the working electrode and an aqueous solution of a metal source as the electrolyte, a three-electrode system is used for electrodeposition to obtain a cobalt-based electrocatalyst doped with lanthanides. The metal source includes a water-soluble cobalt source or a mixed metal source. The mixed metal source includes a water-soluble cobalt source and a water-soluble lanthanide metal source. The lanthanide metal in the water-soluble lanthanide metal source includes one or more of La, Ce, and Pr.

[0014] Preferably, the deposition voltage of the three-electrode system electrodeposition is -0.01 to -0.1 V; the deposition temperature is 5 to 50 °C; and the deposition time is 20 to 3600 s.

[0015] Preferably, the molar ratio of water-soluble cobalt source to water-soluble lanthanide metal source in the mixed metal source is 6~9:1~4; the solid-liquid ratio of the acid-treated substrate to the electrolyte is 1 g:10~40 mL; and the concentration of water-soluble cobalt source in the electrolyte is 25~100 mmol / L.

[0016] Preferably, the reference electrode of the three-electrode system is an Ag / AgCl electrode or a Hg / HgO electrode, and the counter electrode is a platinum wire electrode, a platinum sheet electrode, or a platinum mesh electrode.

[0017] This invention provides the application of the cobalt-based electrocatalyst described in the above technical solution or the cobalt-based electrocatalyst prepared by the preparation method described in the above technical solution in the electrocatalytic preparation of aromatic diacids from hydroxy aromatic aldehydes or the electrocatalytic preparation of oxygen from water.

[0018] Preferably, the hydroxy aromatic aldehyde includes 5-hydroxymethylfurfural.

[0019] This invention provides a cobalt-based electrocatalyst, which utilizes Co(OH)₂ nanosheets and / or Co₇Ln₃(OH)₂. x Nanosheets are used as the active component. Cobalt hydroxide exhibits excellent redox capabilities and high catalytic activity for HMFOR. Lanthanides, represented by lanthanum (La), cerium (Ce), and praseodymium (Pr), possess abundant 4f electron configurations. These electron energy levels can interact with the energy levels of the reactants. Doping with these lanthanides can further enhance the catalytic activity of the cobalt-based electrocatalyst for HMFOR. The cobalt-based electrocatalyst provided by this invention operates at a current of 100 mA·cm⁻¹. -2 The voltage drops to as low as 1.35 V (V vs The cobalt-based electrocatalyst (RHE) can effectively suppress OER activity, exhibits excellent electron conduction efficiency, and can achieve highly efficient electrocatalytic oxidation of HMF to FDCA under low potential and high current density conditions. It also shows high catalytic activity for HMFOR, enabling the reaction to occur with lower energy consumption and improving energy conversion efficiency. Using the cobalt-based electrocatalyst provided by this invention to electrocatalyze the preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural, the conversion rate of 5-hydroxymethylfurfural reached 100%, and the yield of 2,5-furandicarboxylic acid reached 99.9%, indicating that the cobalt-based electrocatalyst provided by this invention has high electrocatalytic conversion and yield, strong stability, and fast response speed.

[0020] This invention provides a method for preparing the cobalt-based electrocatalyst described in the above technical solution. The preparation method provided by this invention is simple to operate, low in cost, green and environmentally friendly, has wide applicability, and is suitable for industrial production. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 Co7Pr3(OH) x Scanning electron microscope image of the electrocatalyst;

[0023] Figure 2 This is a scanning electron microscope image of the Co(OH)2 electrocatalyst.

[0024] Figure 3 Linear sweep voltammetry comparison of OER and HMFOR catalyzed by cobalt-based electrocatalysts;

[0025] Figure 4 It is Co7Ce3(OH) x CV curves of the oxygen evolution reaction under different scan rates using an electrocatalyst;

[0026] Figure 5 The CV curves for the oxygen evolution reaction of the Co(OH)2 electrocatalyst under different scan rates are shown.

[0027] Figure 6 This is an electrochemical impedance spectroscopy diagram of a cobalt-based electrocatalyst. Detailed Implementation

[0028] This invention provides a cobalt-based electrocatalyst comprising an acid-treated substrate and an active component deposited on the acid-treated substrate; the active component comprises Co(OH)₂ nanosheets and / or Co₇Ln₃(OH)₂. x Nanosheets; the Co7Ln3(OH) x Ln is one or more of La, Ce and Pr, and x is 20~33; the acid-treated substrate includes acid-treated carbon materials and / or acid-treated foam metal.

[0029] In this invention, the Co(OH)₂ nanosheets and Co₇Ln₃(OH)₂ nanosheets are used. x The thickness of the nanosheet is preferably 0.5~2 nm, more preferably 0.8~1.2 nm, and most preferably 1 nm.

[0030] In this invention, the acid-treated carbon material preferably comprises carbon paper and / or carbon cloth, more preferably carbon paper. In this invention, the acid-treated foamed metal is preferably made of foamed metal; the foamed metal preferably comprises one or more of foamed copper, foamed iron, and foamed nickel, more preferably foamed copper. In this invention, the pore size of the foamed metal is preferably 0.5~0.6 mm, more preferably 0.52~0.58 mm, and most preferably 0.54~0.56 mm; the porosity of the foamed metal is preferably ≥90%, more preferably 92~96%, and most preferably 93~95%; the density of the foamed metal is preferably 0.1~1.2 g / cm³. 3More preferably 0.3~1 g / cm³ 3 The optimal value is 0.5~0.8 g / cm³. 3 .

[0031] In this invention, the acid-treated substrate is preferably a hydrochloric acid-treated substrate. The preparation method of the hydrochloric acid-treated substrate preferably includes the following steps: immersing the substrate in hydrochloric acid to obtain the hydrochloric acid-treated substrate. In this invention, the concentration of the hydrochloric acid is preferably 0.1~0.4 mol / L, more preferably 0.2~0.3 mol / L; the immersion temperature is preferably room temperature; the immersion time is preferably 5~30 min, more preferably 10~25 min, and most preferably 15~20 min. The substrate is preferably cut into pieces before use. This invention does not have a special limitation on the size of the cut substrate; the cut substrate only needs to be usable. After immersion in hydrochloric acid, this invention preferably further includes: sequentially washing the obtained hydrochloric acid-immersed substrate with alcohol, washing with water, and drying to obtain the hydrochloric acid-treated substrate. In this invention, the alcohol used for alcohol washing is preferably ethanol. This invention does not have a special limitation on the water washing; washing until neutral is sufficient. This invention does not have a special limitation on the drying conditions; drying to constant weight is sufficient.

[0032] This invention provides a method for preparing the cobalt-based electrocatalyst described in the above technical solution, comprising the following steps: using an acid-treated substrate as the working electrode and an aqueous solution of a metal source as the electrolyte, performing electrodeposition in a three-electrode system to obtain a lanthanide-doped cobalt-based electrocatalyst; the metal source includes a water-soluble cobalt source or a mixed metal source; the mixed metal source includes a water-soluble cobalt source and a water-soluble lanthanide metal source, wherein the lanthanide metal in the water-soluble lanthanide metal source includes one or more of La, Ce, and Pr.

[0033] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0034] In this invention, the molar ratio of the water-soluble cobalt source to the water-soluble lanthanide metal source in the mixed metal source is preferably 6-9:1-4, more preferably 7-8:2-3. In this invention, the solid-liquid ratio of the acid-treated substrate to the electrolyte is preferably 1 g:10-40 mL, more preferably 1 g:15-25 mL, and most preferably 1 g:20 mL. In this invention, the concentration of the water-soluble cobalt source in the electrolyte is preferably 25-100 mmol / L, more preferably 40-60 mmol / L, and most preferably 50 mmol / L.

[0035] In this invention, the reference electrode of the three-electrode system is preferably an Ag / AgCl electrode or a Hg / HgO electrode; the counter electrode is preferably a platinum wire electrode and / or a platinum mesh electrode.

[0036] In this invention, the electrodeposition method of the three-electrode system is preferably a constant potential method. In this invention, the deposition voltage of the three-electrode system is preferably -0.01 to -0.1 V, more preferably -0.03 to -0.08 V, and most preferably -0.05 V; the deposition temperature of the three-electrode system is preferably 5 to 50 °C, more preferably 10 to 40 °C, and most preferably 20 to 30 °C; the deposition time of the three-electrode system is preferably 20 to 3600 s, more preferably 800 to 2000 s, and most preferably 1200 s.

[0037] This invention provides the application of the cobalt-based electrocatalyst described in the above-described technical solutions, or the cobalt-based electrocatalyst prepared by the preparation method described in the above-described technical solutions, in the electrocatalytic preparation of aromatic diacids from hydroxy aromatic aldehydes or the electrocatalytic preparation of oxygen from water. In this invention, the hydroxy aromatic aldehyde preferably includes 5-hydroxymethylfurfural.

[0038] To further illustrate the present invention, the cobalt-based electrocatalyst, its preparation method, and its application provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] Cut commercially available copper foam into 1×1 cm pieces. 2 Small pieces of the solution were soaked in 0.2 mol / L dilute hydrochloric acid for 10 min, washed with ethanol and deionized water until neutral, and dried to obtain hydrochloric acid-treated copper foam.

[0041] The electrolyte consisted of 1.4 mmol cobalt acetate, 0.6 mmol lanthanum acetate, and 40 mL deionized water.

[0042] In a three-electrode electrolytic cell, hydrochloric acid-treated copper foam was placed on a motor clamp as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire electrode as the counter electrode. All three electrodes were immersed in a prepared electrolyte (40 mL). At room temperature, using a CHI660e Chenhua electrochemical workstation, Co7La3(OH) was electrodeposited at -0.05 V for 1200 s. x Co7La3(OH) was deposited on the surface of hydrochloric acid-treated copper foam to obtain Co7La3(OH). x Electrocatalyst.

[0043] Example 2

[0044] Cut commercially available copper foam into 1×1 cm pieces. 2 Small pieces of the solution were soaked in 0.2 mol / L dilute hydrochloric acid for 10 min, washed with ethanol and deionized water until neutral, and dried to obtain hydrochloric acid-treated copper foam.

[0045] The electrolyte consisted of 1.4 mmol cobalt acetate, 0.6 mmol cerium acetate, and 40 mL deionized water.

[0046] In a three-electrode electrolytic cell, hydrochloric acid-treated copper foam was placed on a motor clamp as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire electrode as the counter electrode. All three electrodes were immersed in the prepared electrolyte. At room temperature, using a CHI660e Chenhua electrochemical workstation, Co7Ce3(OH) was electrodeposited at -0.05 V for 1200 s. x Co7Ce3(OH) was deposited on the surface of hydrochloric acid-treated copper foam to obtain Co7Ce3(OH). x Electrocatalyst.

[0047] Example 3

[0048] Cut commercially available copper foam into 1×1 cm pieces. 2 Small pieces of the solution were soaked in 0.2 mol / L dilute hydrochloric acid for 10 min, washed with ethanol and deionized water until neutral, and dried to obtain hydrochloric acid-treated copper foam.

[0049] The electrolyte consists of 1.4 mmol cobalt acetate, 0.6 mmol praseodymium acetate, and 40 mL deionized water.

[0050] In a three-electrode electrolytic cell, hydrochloric acid-treated copper foam was placed on a motor clamp as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire electrode as the counter electrode. All three electrodes were immersed in the prepared electrolyte. At room temperature, using a CHI660e Chenhua electrochemical workstation, Co7Pr3(OH) was electrodeposited at -0.05 V for 1200 s. x Co7Pr3(OH) was deposited on the surface of hydrochloric acid-treated copper foam to obtain Co7Pr3(OH). x Electrocatalyst.

[0051] Example 4

[0052] Cut commercially available copper foam into 1×1 cm pieces. 2 Small pieces of the solution were soaked in 0.2 mol / L dilute hydrochloric acid for 10 min, washed with ethanol and deionized water until neutral, and dried to obtain hydrochloric acid-treated copper foam.

[0053] The electrolyte consists of 2 mmol cobalt acetate and 40 mL deionized water.

[0054] In a three-electrode electrolytic cell, hydrochloric acid-treated copper foam was placed on a motor clamp as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire electrode as the counter electrode. These three electrodes were immersed in the prepared electrolyte. At room temperature, using a CHI660e Chenhua electrochemical workstation, Co(OH)₂ was electrodeposited on the surface of the hydrochloric acid-treated copper foam for 1200 s at -0.05 V, yielding a Co(OH)₂ electrocatalyst.

[0055] Figure 1 Co7La3(OH) x Scanning electron microscope (SEM) image of the electrocatalyst. Figure 2 Here is a scanning electron microscope image of the Co(OH)₂ electrocatalyst, from... Figures 1-2 It can be seen that the active component Co7Pr3(OH) in the catalyst prepared by this invention is present. x Co(OH)₂ exhibits the typical hexagonal morphology of metal hydroxides. Compared to Co(OH)₂, Co₇Pr₃(OH)₂ shows a different morphology due to the addition of Pr. x The edges of the hexagonal sheet become blunt, and its shape tends to be amorphous.

[0056] Test Example 1

[0057] The Co(OH)₂ electrocatalysts and Co₇La₃(OH)₂ prepared in Examples 1-4 were compared. x Electrocatalyst, Co7Ce3(OH) x Electrocatalyst and Co7Pr3(OH) x The electrocatalyst was subjected to linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The test methods and results are as follows.

[0058] 1. Linear sweep voltammetry: In an electrolytic cell containing 1 mol / L potassium hydroxide, Co(OH)₂ electrocatalyst and Co₇La₃(OH)₃ were used respectively. x Electrocatalyst, Co7Ce3(OH) x Electrocatalyst and Co7Pr3(OH) x The electrocatalyst was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum wire electrode as the counter electrode. Tests were conducted using a CHI660e electrochemical workstation, with accompanying computer software for data acquisition and processing. The electrochemical range was 0.5122–1.7122 V (V0.05). vs Linear scan voltammetry was performed at a scan rate of 0.005 V / s within the RHE potential range, and stable linear scan voltammetry was recorded.

[0059] Figure 3The graphs show a linear sweep voltammetry comparison of OER and HMFOR catalyzed by cobalt-based electrocatalysts, where a is the OER curve catalyzed by Co(OH)2 electrocatalyst, and b is the OER curve catalyzed by Co7La3(OH). x OER curve of electrocatalyst, where c represents Co7Ce3(OH). x OER curve of electrocatalyst, where d represents Co7Pr3(OH). x The OER curves for electrocatalysis are shown, e is the HMFOR curve for Co(OH)2 electrocatalyst, and f is the OER curve for Co7La3(OH). x HMFOR curve catalyzed by electrocatalyst, where g represents Co7Ce3(OH). x HMFOR curve catalyzed by the electrocatalyst, where h represents Co7Pr3(OH). x HMFOR curves of electrocatalyst catalysis.

[0060] Figure 3 The results show that, compared with the undoped Co(OH)2 electrocatalyst, the LSV curves of the electrocatalysts doped with lanthanide metals La, Ce, and Pr exhibit larger current densities under the same voltage conditions, indicating that the electrocatalysts doped with lanthanide metals have much higher reaction performance for HMFOR than for OER.

[0061] 2. Cyclic voltammetry scan: In an electrolytic cell containing 1 mol / L potassium hydroxide, Co(OH)₂ electrocatalyst and Co₇La₃(OH)₂ were used respectively. x Electrocatalyst, Co7Ce3(OH) x Electrocatalyst and Co7Pr3(OH) x The electrocatalyst was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum wire electrode as the counter electrode. Tests were conducted using a CHI660e electrochemical workstation, with data acquisition and processing performed using its associated computer software. The electrochemical range was 0.7622–0.8622 V (V0.05). vs Cyclic voltammetric scans were performed within the RHE potential range, with a scan rate range of 20–100 mV·s. -1 .

[0062] Figure 4 It is Co7Ce3(OH) x CV curves of the oxygen evolution reaction under different scan rates using an electrocatalyst. Figure 5 The image shows the CV curves of the oxygen evolution reaction (OER) of the Co(OH)₂ electrocatalyst under different scan rates, where scan rate a is 20 mV·s. -1 The scan rate of b is 40 mV·s -1 The scan rate of c is 60 mV·s -1 The scan rate of d is 80 mV·s-1 The scanning speed of e is 100 mV·s -1 .Depend on Figure 4 and 5 It can be seen that the current density of the CV curve increases linearly with the increase of the scan rate. The current density of Co7Ce3(OH) can be calculated from the cyclic voltammetry. x The double-layer capacitance (denoted as Cdl) of the electrocatalyst and the Co(OH)2 electrocatalyst in the non-Radida region is 0.0189 mF / cm. 2 and 0.0087 mF / cm 2 This indicates that the addition of lanthanides significantly increases the double-layer capacitance and electrochemical active area of ​​the electrocatalyst, exposing more active sites and thus significantly improving its catalytic performance.

[0063] 3. Electrochemical impedance spectroscopy: In 10 mL of 1 mol / L potassium hydroxide aqueous solution, Co(OH)₂ electrocatalyst and Co₇La₃(OH)₂ were used respectively. x Electrocatalyst, Co7Ce3(OH) x Electrocatalyst and Co7Pr3(OH) x The electrocatalyst was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum wire electrode as the counter electrode. The tests were conducted using a CHI660e electrochemical workstation, with the accompanying computer software used for data acquisition and processing. Electrochemical impedance spectroscopy was performed at an OCP voltage of 0.005 V, within a high frequency range of 1,000,000 Hz to 0.001 Hz.

[0064] Figure 6 Electrochemical impedance spectroscopy diagrams for cobalt-based electrocatalysts, such as... Figure 6 As shown in the EIS curve, the electron transfer resistance (diameter of the first semicircle in the Rct curve) of the lanthanide-doped electrocatalyst is significantly smaller than that of the undoped Co(OH)2 electrocatalyst. This indicates that the addition of lanthanides significantly enhances conductivity and enables faster charge transfer on its surface, further verifying its excellent electrocatalytic performance from the perspective of electrode kinetics.

[0065] Example 5

[0066] The cobalt-based electrocatalyst was prepared according to the method of Example 3, the only difference being that the electrodeposition currents were -0.01 A and -0.1 A, respectively. The prepared cobalt-based electrocatalyst was tested at a current density of 50 mA·cm⁻¹. -2 The voltage values ​​read at that time are shown in Table 1.

[0067] Table 1 Effect of electrodeposition current on cobalt-based electrocatalysts

[0068]

[0069] As shown in Table 1, under otherwise constant conditions, the cobalt-based electrocatalyst exhibits the highest activity at an electrodeposition current of -0.05 A. When the voltage is greater than or less than -0.05 A, the performance of the electrocatalyst is lower. During LSV testing, a higher voltage is required to achieve the same current density, and the maximum current density value is smaller within the testing range.

[0070] Example 6

[0071] The cobalt-based electrocatalyst was prepared according to the method of Example 3, the only difference being the electrodeposition time, which was 600 s and 1800 s, respectively. The prepared cobalt-based electrocatalyst was tested at a current density of 50 mA·cm⁻¹. -2 The voltage values ​​read at that time are shown in Table 2.

[0072] Table 2 Effect of electrodeposition time on cobalt-based electrocatalysts

[0073]

[0074] As shown in Table 2, under otherwise constant conditions, the cobalt-based electrocatalyst exhibits the highest activity when electrodeposited for 1200 s. The performance of the electrocatalyst is lower when the electrodeposition time is longer or shorter than 1200 s. During LSV testing, a higher voltage is required to achieve the same current density, and the maximum current density value is smaller within the test range.

[0075] Example 7

[0076] Cobalt-based electrocatalysts were prepared according to the method of Example 1, the only difference being that the molar ratios of cobalt acetate to lanthanum acetate were 9:1 and 4:6, respectively. The prepared cobalt-based electrocatalysts were tested at a current density of 50 mA·cm⁻¹. -2 The voltage values ​​read at that time are shown in Table 3.

[0077] Co7La3(OH) x Taking electrocatalysts as an example, the effect of the molar ratio of cobalt acetate to lanthanum acetate on cobalt-based electrocatalysts was investigated within the range of 9:1 to 1:9.

[0078] Table 3 Effect of the molar ratio of cobalt acetate to lanthanum acetate on cobalt-based electrocatalysts

[0079]

[0080] As shown in Table 3, under otherwise constant conditions, the molar ratio of cobalt acetate to lanthanum acetate in the range of 6-9:1-4 has little effect on the catalytic performance of cobalt-based electrocatalysts. However, when the amount of lanthanum acetate is greater than or equal to the amount of cobalt acetate, the catalytic performance of the electrocatalyst decreases. During LSV testing, a higher voltage is required to achieve the same current density, and the maximum current density value is smaller within the test range.

[0081] Example 8

[0082] The cobalt-based electrocatalyst was prepared according to the method of Example 3, the only difference being that the copper foam substrate was not treated with hydrochloric acid. The resulting cobalt-based electrocatalyst was tested at a current density of 50 mA·cm⁻¹. -2 The voltage values ​​read at that time are shown in Table 4.

[0083] Table 4. Effect of hydrochloric acid treatment on cobalt-based electrocatalysts on whether the copper foam substrate has been treated with hydrochloric acid.

[0084]

[0085] As shown in Table 4, under otherwise identical conditions, the performance of the electrocatalyst deposited with hydrochloric acid-treated copper foam is significantly higher than that of the electrocatalyst deposited with untreated copper foam. During LSV testing, a higher voltage is required to achieve the same current density, and the maximum current density value is smaller within the test range.

[0086] Test Example 2

[0087] The electrolytic performance of cobalt-based electrocatalysts under different voltages was tested. The performance test method for HMF electrocatalytic oxidation was as follows: 0.1 mmol of HMF was added to 10 mL of 1 mol / L potassium hydroxide aqueous solution to prepare a 10 mM HMF alkaline solution. Co(OH)2 electrocatalyst and Co7La3(OH)2 electrocatalyst were then used respectively. x Electrocatalyst, Co7Ce3(OH) x Electrocatalyst and Co7Pr3(OH) x The electrocatalyst was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum wire electrode as the counter electrode. Tests were conducted using a CHI660e electrochemical workstation, with data acquisition and processing performed using its accompanying computer software. Tests were conducted at 1.3122 V, 1.3622 V, 1.4122 V, 1.4622 V, 1.5122 V, and 1.5622 V (V...). vs. Electrocatalytic oxidation of HMF was performed at RHE voltage, and the reaction was detected using an Agilent 1260 high-performance liquid chromatograph. Co7La3(OH) xThe Faraday efficiency (FE), FDCA selectivity, and HMF conversion of the electrocatalyst at different voltages are shown in Table 5.

[0088] Table 5 Co7La3(OH) x Electrolysis efficiency of electrocatalysts at different voltages

[0089]

[0090] As shown in Table 5, when the voltage is ≤1.4122 V (V vs At RHE (Reactive High-Efficiency Reactions), the electrocatalyst exhibits near 100% FDCA selectivity, near 100% HMF conversion, and near 100% Faradaic efficiency. When the voltage exceeds 1.4622 V, the HMF conversion, FDCA selectivity, and Faradaic efficiency all decrease significantly. This is because the reaction solution undergoes the OER reaction under high voltage conditions, competing with the HMFOR target reaction, causing some charge to participate in the OER reaction, thus lowering the performance indicators of the electrocatalyst.

[0091] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A cobalt-based electrocatalyst characterized in that, Includes an acid-treated substrate and active components deposited on the acid-treated substrate; The active component is Co7Ln3(OH). x Nanosheets; the Co7Ln3(OH) x In this context, Ln represents one or more of La, Ce, and Pr. x The value is 20~33; the acid-treated substrate includes acid-treated carbon materials and / or acid-treated foamed metals.

2. The cobalt-based electrocatalyst according to claim 1, characterized in that, said Co7Ln3(OH) x The thickness of the nanosheet is 0.5-2 nm.

3. The cobalt-based electrocatalyst of claim 1, wherein, The acid-treated carbon material includes carbon paper and / or carbon cloth; the acid-treated foam metal includes one or more of foamed copper, foamed iron, and foamed nickel.

4. The cobalt-based electrocatalyst of claim 1 or 3, wherein, The acid-treated substrate is a hydrochloric acid-treated substrate.

5. A method for producing the cobalt-based electrocatalyst according to any one of claims 1 to 4, characterized by, Includes the following steps: Using an acid-treated substrate as the working electrode and an aqueous solution of a metal source as the electrolyte, a three-electrode electrodeposition system was performed to obtain a cobalt-based electrocatalyst doped with lanthanides; the metal source is a mixed metal source; the mixed metal source includes a water-soluble cobalt source and a water-soluble lanthanide metal source, wherein the lanthanide metal in the water-soluble lanthanide metal source is one or more of La, Ce and Pr; The deposition voltage for electrodeposition in the three-electrode system is -0.01 to -0.1V; The deposition temperature is 5~50℃; the deposition time is 20~3600s.

6. The production method according to claim 5, wherein The molar ratio of the water-soluble cobalt source and the water-soluble lanthanide metal source in the mixed metal source is 7:

3. The solid-liquid ratio of the acid-treated substrate to the electrolyte is 1g:10~40mL; The concentration of the water-soluble cobalt source in the electrolyte is 25~100 mmol / L.

7. The production method according to claim 5 or 6, characterized by, The reference electrode of the three-electrode system is an Ag / AgCl electrode or a Hg / HgO electrode, and the counter electrode is a platinum wire electrode, a platinum sheet electrode, or a platinum mesh electrode.

8. The application of the cobalt-based electrocatalyst according to any one of claims 1 to 4 or the cobalt-based electrocatalyst prepared by the preparation method according to any one of claims 5 to 7 in the electrocatalytic preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural.

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