Preparation method and application of single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input

Abstract

This invention belongs to the field of nanomaterials and electrocatalysis technology, and relates to a method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input and its application. The preparation method includes: dissolving a nickel source, a cobalt source, and terephthalic acid in a molar ratio of 1.5~1:1:1~1.5 in a mixed solvent of DMF and water; adding anhydrous ruthenium trichloride; ultrasonically dispersing the mixture; and then performing electrodeposition using a pulse electrodeposition method. Vacuum drying yields the Ru1NiCo-BDC catalyst. In this catalyst, Ru is dispersed in single-atom form within a NiCo-BDC nanosheet array. This catalyst achieves a Faradaic efficiency of 98%~100% for the electrooxidation of glycerol to formic acid within a wide potential window of 1.15~1.8 V vs. RHE, and at 1 A cm⁻¹... ‑2 It can operate stably under industrial-grade current densities; even under a wide current fluctuation range of 1.27~14A, it can still maintain a Faraday efficiency of 98±2%, demonstrating excellent dynamic power supply adaptability. The prepared catalyst can also be used for the electro-oxidation of biomass such as ethylene glycol and glucose to produce formic acid, showing good prospects for large-scale application.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials and electrocatalysis technology, and relates to nano-electrocatalysts, specifically to a method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input and its application. Background Technology

[0002] Utilizing renewable energy sources such as wind and solar power to drive electrochemical reactions for the green manufacturing of high-value-added chemicals is a crucial pathway to achieving "dual carbon" goals and transforming the chemical industry. Glycerol, a significant byproduct of the biodiesel industry, is widely available and inexpensive. Its efficient conversion into high-value-added chemicals such as formic acid through electrooxidation has significant economic and environmental value. Currently, nickel-based, cobalt-based, and composite oxide catalysts are widely used in the electrooxidation of glycerol. However, most existing catalytic systems follow a surface adsorption control mechanism, where organic substrates, intermediates, and hydroxyl reactive species (OH*) compete for limited surface active sites during the reaction. While increasing the reaction potential or current density significantly improves the OH* formation rate, it also promotes side reactions such as oxygen evolution reaction, leading to a decrease in the Faradaic efficiency of the target product.

[0003] In recent years, researchers have improved catalyst activity and target product Faraday efficiency through strategies such as constructing heterostructures, controlling electronic structures, and designing bimetallic synergistic catalytic systems. However, these strategies cannot fundamentally solve the competitive adsorption problem between active species and organic substrates. Under high current density conditions, the active sites on the catalyst surface rapidly saturate, side reactions are significantly enhanced, leading to a decrease in target product selectivity and energy utilization efficiency.

[0004] On the other hand, renewable energy sources such as wind and solar power are significantly intermittent and fluctuating, with current and potential constantly changing during actual power supply. Traditional electrocatalytic systems are prone to problems such as fluctuations in catalytic activity, changes in product distribution, and a decrease in Faradaic efficiency under dynamic power supply conditions, leading to a significant mismatch between renewable energy supply and the electrosynthesis process. Therefore, developing an electrocatalytic system that can adapt to fluctuating power input and maintain high Faradaic efficiency and high stability over a wide potential range is of great significance for promoting the large-scale application of renewable energy-driven electrosynthesis technology and has become a key scientific problem and technological challenge that urgently needs to be solved in the field of electrocatalysis. Summary of the Invention

[0005] To overcome the problems of difficulty in balancing activity and Faraday efficiency, poor adaptability to dynamic operating conditions, and serious side reactions in the electrocatalytic glycerol oxidation process of existing technologies, this invention discloses a method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input.

[0006] Technical solution

[0007] A method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst (Ru1NiCo-BDC) suitable for fluctuating power input includes: dissolving a nickel source, a cobalt source, and terephthalic acid in a mixed solvent of DMF and water in a molar ratio of Ni, Co, and terephthalic acid of 1.5–1:1:1–1.5, ultrasonically dispersing the solution, and then adding anhydrous ruthenium trichloride; ultrasonically dispersing the above mixed solution, then performing electrodeposition using a pulse electrodeposition method, and finally vacuum drying to obtain the target catalyst material.

[0008] In a preferred embodiment of the present invention, the nickel source is one or more of nickel nitrate, nickel chloride, or nickel acetate, with nickel nitrate being preferred.

[0009] In a preferred embodiment of the present invention, the cobalt source is one or more of cobalt nitrate, cobalt chloride, or cobalt acetate, with cobalt nitrate being preferred.

[0010] In a preferred embodiment of the present invention, the molar ratio of Ni, Co and terephthalic acid is any one of 1.5:1:1, 1:1.2:1.5, or 1:1:1.5, or any ratio among the three.

[0011] In a preferred embodiment of the present invention, the amount of anhydrous ruthenium trichloride added is 0.5-5% of the total amount of the nickel source and cobalt source.

[0012] In a preferred embodiment of the present invention, the mixed solution is ultrasonically dispersed for more than 1 hour.

[0013] In a preferred embodiment of the present invention, the pulse electrodeposition method employs a three-electrode system, wherein the reference electrode is Hg / HgO, the counter electrode is a platinum sheet, and the working electrode is nickel foam.

[0014] In a preferred embodiment of the present invention, during the electrodeposition process, pulse potentials of -10V and 0V are applied alternately for durations of 5s and 10s, respectively, and the target electrocatalytic material is obtained after 60-80 cycles.

[0015] In a preferred embodiment of the present invention, the vacuum drying temperature is 50-70°C and the time is 10-60 min.

[0016] Experimental results show that the microstructure of the Ru1NiCo-BDC electrocatalyst is a nanosheet array.

[0017] The present invention also discloses the application of the single-atom Ru-modified NiCo-based metal-organic framework (Ru1NiCo-BDC) in the electrocatalytic oxidation of biomass to prepare formic acid; wherein the biomass includes glycerol, ethylene glycol or glucose.

[0018] The Ru1NiCo-BDC electrocatalyst exhibits both high activity and resistance to intermittent energy fluctuations in the electrocatalytic oxidation of biomass.

[0019] When this material is applied to the field of electrocatalytic biomass oxidation, the Ru1NiCo-BDC catalyst exhibits a formic acid faradaic efficiency of close to 98~100% at a voltage of 1.15-1.8V vs. RHE, and the highest current can reach the ampere level.

[0020] Beneficial effects

[0021] (1) Achieve effective decoupling between activity and Faraday efficiency

[0022] In traditional systems, an increase in current density is usually accompanied by a decrease in Faraday efficiency. However, this invention alleviates the coupling relationship between activity and Faraday efficiency by adjusting the single-atom Ru, and maintains high formic acid Faraday efficiency over a wide potential window.

[0023] (2) Excellent performance in industrial applications

[0024] The catalyst of this invention exhibits excellent performance in both H-type and MEA electrolyzers, can operate stably at an industrial-grade current density of 1 A cm⁻², and maintains a formic acid faradaic efficiency of over 95%, demonstrating good potential for large-scale application.

[0025] (3) It has excellent dynamic power supply adaptability.

[0026] The catalyst of this invention can adapt to the current fluctuations generated during renewable energy power supply. Under a wide current fluctuation range of 1.27-14 A, it can still maintain a formic acid faradaic efficiency of 98±2%, which is significantly better than traditional catalytic systems. This solves the matching problem between the intermittency of renewable energy and the stable output of products from the electrosynthesis process. Attached Figure Description

[0027] Figure 1 XRD diffraction pattern of the Ru1NiCo-BDC catalyst prepared in Example 1;

[0028] Figure 2 X-ray photoelectron spectroscopy analysis of the Ru1NiCo-BDC catalyst prepared in Example 1;

[0029] Figure 3 Synchrotron radiation analysis of the Ru1NiCo-BDC catalyst prepared in Example 1;

[0030] Figure 4 Infrared spectroscopy analysis of the Ru1NiCo-BDC catalyst prepared in Example 1;

[0031] Figure 5Transmission spectrum of the Ru1NiCo-BDC catalyst prepared in Example 1;

[0032] Figure 6 LSV curve of the Ru1NiCo-BDC catalyst prepared in Example 1;

[0033] Figure 7 Example 1: FE at different voltages during glycerol oxidation using the Ru1NiCo-BDC catalyst prepared in Example 1. formate ;

[0034] Figure 8 The voltage, current, and FE of the Ru1NiCo-BDC catalyst prepared in Example 1 under fluctuating energy input. formate Line graph;

[0035] Figure 9 LSV curves and FE values ​​of the Ru1NiCo-BDC catalyst prepared in Example 11 at different voltages during ethylene glycol oxidation. formate ;

[0036] Figure 10 LSV curves and FE values ​​of the Ru1NiCo-BDC catalyst prepared in Example 12 at different voltages during glucose oxidation. formate . Detailed Implementation

[0037] The present invention will be described in detail below with reference to embodiments to enable those skilled in the art to better understand the present invention, but the present invention is not limited to the following embodiments. Unless otherwise specified, the raw materials and equipment involved in the embodiments are all conventional commercially available products in the art.

[0038] Example 1

[0039] (1) Disperse 1.5 mmol nickel nitrate, 1 mmol cobalt nitrate and 1 mmol terephthalic acid evenly in a mixed solution containing 20 ml DMF and 1 ml water, and sonicate to obtain solution A;

[0040] (2) Add 20 mg of ruthenium trichloride to solution A and sonicate for 1 h to obtain mixed solution B;

[0041] (3) The target electrocatalyst material was obtained by alternately applying pulse potentials of -10 V and 0 V in a three-electrode system with Hg / HgO as the reference electrode, platinum sheet as the counter electrode and nickel foam as the working electrode using pulse electrode deposition for 5 seconds and 10 seconds respectively.

[0042] (4) The electrocatalyst was vacuum dried at a temperature of 60°C for 60 min to obtain Ru1NiCo-BDC electrode material;

[0043] (5) Using the above-mentioned Ru1NiCo-BDC electrode material as the anode, it is assembled with a commercial Pt / C cathode and a Nafion membrane to form a membrane electrode assembly (MEA) with an effective area of ​​5×5cm. 2 The test conditions were as follows: fluctuating power input was simulated using a stepped square wave current mode, with the current cycling between 1.27 A and 14 A, each step lasting 60 seconds, for a total test duration of 2 hours. This method is also applicable to real-world fluctuating power input scenarios such as outdoor solar power.

[0044] The material properties and its electrocatalytic oxidation performance of glycerol were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-performance liquid chromatography (HPLC), and an electrochemical workstation.

[0045] like Figure 1 As shown, the sample Ru1NiCo-BDC obtained in Example 1 exhibits obvious Ni-MOF characteristic peaks.

[0046] like Figure 2 The image shows the Ru 3p X-ray photoelectron spectrum of the sample Ru1NiCo-BDC obtained in Example 1.

[0047] like Figure 3 As shown, the extended X-ray absorption fine structure fitting results of the sample Ru1NiCo-BDC obtained in Example 1 clarify that Ru exists in the catalyst in the form of single atoms.

[0048] like Figure 4 As shown, the infrared spectrum of the Ru1NiCo-BDC sample prepared in this invention demonstrates that the terephthalic acid ligand was successfully bonded to the metal source.

[0049] like Figure 5 As shown in the transmission spectrum of the Ru1NiCo-BDC sample prepared in this invention, the catalyst has a nanosheet structure.

[0050] like Figure 6 As shown, the electrochemical performance test curve of the Ru1NiCo-BDC sample prepared in this invention reaches 1000 mA cm⁻¹ at 1.7 V vs. RHE. -2 .

[0051] like Figure 7 As shown, the FE of the Ru1NiCo-BDC sample prepared in this invention under different voltages formateIts Faraday efficiency can reach over 98% in the potential window of 1.15-1.8 V vs. RHE.

[0052] like Figure 8 As shown, the Ru1NiCo-BDC sample prepared in this invention is 5×5 cm⁻¹ 2 In the MEA, under fluctuating energy input, the current, voltage, and FE of the electrocatalytic oxidation of glycerol are... formate The curve shows that it can achieve a Faraday efficiency of over 98% at currents of 1-14 A.

[0053] Comparative Example 1

[0054] The process was essentially the same as in Example 1, except that anhydrous ruthenium trichloride (i.e., no Ru source) was added to prepare the NiCo-BDC catalyst. Under the same test conditions, the current of this NiCo-BDC catalyst at 1.6 V vs. RHE was only 404.9 mA cm⁻¹. -2 It exhibits the highest formic acid faradaic efficiency at 1.45 V vs. RHE potential, at only 85%, which is significantly inferior to Example 1.

[0055] Example 2

[0056] It is basically the same as Example 1, except that ruthenium trichloride is replaced with 5 mg.

[0057] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current can reach 920 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0058] Example 3

[0059] It is basically the same as Example 1, except that ruthenium trichloride is replaced with 10 mg.

[0060] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current can reach 892 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0061] Example 4

[0062] It is basically the same as Example 1, except that ruthenium trichloride is replaced with 25 mg.

[0063] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formateMaintaining above 95%, the current can reach 981 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0064] Example 5

[0065] It is basically the same as Example 1, except that the ratio of nickel nitrate:cobalt nitrate:terephthalic acid is 1:1.2:1.5 mmol.

[0066] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current reaches 932 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0067] Example 6

[0068] It is basically the same as Example 1, except that the ratio of nickel nitrate:cobalt nitrate:terephthalic acid is 1:1:1.5 mmol.

[0069] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current reaches 880.2 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0070] Example 7

[0071] It is basically the same as Example 1, except that the ratio of DMF:water is 20:2 ml.

[0072] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current can reach 902 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0073] Example 8

[0074] It is basically the same as Example 1, except that the ratio of DMF:water is 20:3 ml.

[0075] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current reaches 951 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0076] Example 9

[0077] It is basically the same as Example 1, except that nickel nitrate is replaced with nickel chloride.

[0078] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current reaches 820.2 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0079] Example 10

[0080] It is basically the same as Example 1, except that cobalt nitrate is replaced with cobalt chloride.

[0081] The prepared Ru1NiCo-BDC catalyst exhibited FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current reaches 859.7 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0082] Example 11

[0083] The reaction was basically the same as in Example 1, except that the reaction substrate was replaced with ethylene glycol.

[0084] like Figure 9 As shown, the prepared Ru1NiCo-BDC catalyst exhibits FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 94%, the current reaches 904 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0085] Example 12

[0086] It is basically the same as Example 1, except that the reaction substrate is replaced with glucose.

[0087] like Figure 10 As shown, the prepared Ru1NiCo-BDC catalyst exhibits FE at potentials of 1.15–1.8 V vs. RHE. formate Maintaining above 95%, the current can reach 480 mA cm⁻¹ at 1.6 V vs. RHE. -2 .

[0088] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input, characterized in that, The process includes the following steps: dissolving nickel source, cobalt source, and terephthalic acid in a mixed solvent of DMF and water in a molar ratio of Ni, Co, and terephthalic acid of 1.5–1:1:1–1.5, followed by ultrasonic dispersion and the addition of anhydrous ruthenium trichloride; then, after ultrasonic dispersion of the above mixed solution, performing electrodeposition using a pulse electrodeposition method, and finally vacuum drying to obtain the final product.

2. The method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input according to claim 1, characterized in that: The nickel source is one or more of nickel nitrate, nickel chloride, or nickel acetate, preferably nickel nitrate; the cobalt source is one or more of cobalt nitrate, cobalt chloride, or cobalt acetate, preferably cobalt nitrate.

3. The method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input according to claim 1, characterized in that: The molar ratio of Ni, Co and terephthalic acid is any one of 1.5:1:1, 1:1.2:1.5, or 1:1:1.5, or any ratio among the three.

4. The method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input according to claim 1, characterized in that: The amount of anhydrous ruthenium trichloride added is 0.5-5% of the total amount of nickel and cobalt sources; the mixed solution is ultrasonically dispersed for more than 1 hour.

5. The method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input according to claim 1, characterized in that: The pulse electrodeposition method employs a three-electrode system, wherein the reference electrode is Hg / HgO, the counter electrode is a platinum sheet, and the working electrode is nickel foam.

6. The method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input according to claim 1, characterized in that: During the electrodeposition process, pulse potentials of -10V and 0V are applied alternately for durations of 5s and 10s, respectively, and the electrodeposition is completed after 60-80 cycles.

7. The method for preparing a single-atom Ru-modified NiCo-BDC electrocatalyst suitable for fluctuating power input according to claim 1, characterized in that: The vacuum drying temperature is 50-70℃, and the time is 10-60 minutes.

8. The single-atom Ru-modified NiCo-BDC electrocatalyst prepared by the method according to any one of claims 1-7, characterized in that: The electrocatalyst has a microstructure of nanosheet array.

9. The application of the single-atom Ru-modified NiCo-BDC electrocatalyst according to claim 8 in the electrocatalytic oxidation of biomass to prepare formic acid.

10. The application of the single-atom Ru-modified NiCo-BDC electrocatalyst according to claim 9 in the electrocatalytic oxidation of biomass to formic acid, characterized in that: The biomass is glycerol, ethylene glycol, or glucose.

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