Cu-ag thin film electrode material, preparation method and application thereof in electrochemical catalytic carbon dioxide reduction

Abstract

The application discloses a Cu-Ag thin film electrode material, a preparation method and application of the Cu-Ag thin film electrode material in electrochemical catalytic carbon dioxide reduction. 2 / 2+ The product faraday efficiency is close to 84%, and the current density can reach 445 mA / cm 2 2 when a voltage of-1.2 V is applied.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical carbon dioxide reduction technology, and relates to a Cu-Ag thin film electrode material, its preparation method, and its application in electrochemical catalytic carbon dioxide reduction. Background Technology

[0002] The extensive use of fossil fuels such as coal, oil, and natural gas has led to a continuous increase in CO2 emissions, resulting in a series of problems including climate warming and global environmental degradation. How to efficiently reduce atmospheric CO2 concentration and convert it into high-value fuels or chemicals is a key research topic. Electrocatalytic CO2 reduction (CO2RR) technology can utilize electricity converted from renewable energy sources at room temperature to convert CO2 into high-value carbon-containing chemicals such as formic acid, methane, carbon monoxide, and ethylene, which is of great significance for sustainable social development.

[0003] Compared to one-carbon products such as formic acid and methane, multi-carbon products have higher economic added value. Therefore, the conversion of CO2 into multi-carbon products using electrocatalytic CO2 reduction technology has always been a research hotspot. Among numerous CO2 reduction electrocatalysts, copper (Cu)-based materials have attracted widespread attention due to their unique electronic structure and their great potential in the synthesis of multi-carbon products (such as ethanol, acetic acid, and ethylene). However, single Cu metal catalysts often struggle to achieve both high selectivity and high efficiency simultaneously, especially exhibiting significant limitations in the selectivity of multi-carbon products. In recent years, researchers have discovered that combining Cu with other metals (such as Ag) can significantly improve catalyst performance. Cu-Ag catalysts combine the advantages of both metals, not only improving the reaction efficiency of CO2 reduction reaction but also enhancing the selectivity of multi-carbon products. Furthermore, Cu-Ag catalysts also possess good stability and a long service life.

[0004] Traditional methods for preparing Cu-Ag catalysts typically include wet chemical methods, electrochemical co-deposition methods, and sol-gel methods. These methods generally suffer from complex processes, high costs, and difficulty in large-scale production. For example, Reference 1 prepared Ag catalysts by simultaneously reducing silver nitrate and copper nitrate with potassium borohydride in an aqueous solution at room temperature. x Cu yBimetallic aerogels (WANG W, GONG S, LIU J, et al. Ag-Cu aerogel for electrochemical CO2 conversion to CO[J]. Journal of Colloid and Interface Science, 2021, 595: 159-67.). However, the preparation process of the above methods is relatively cumbersome, requiring precise control of the concentration and addition order of various reagents. Slight carelessness may affect the performance of the final product. Therefore, there is an urgent need to develop a simple, efficient, and large-scale production method for Cu-Ag catalysts. Summary of the Invention

[0005] To address the problems of insufficient Faradaic efficiency at high current densities and complex and costly preparation of catalytic materials in current electrocatalytic carbon dioxide reduction reactions for the preparation of multi-carbon products, this invention provides a high-performance Cu-Ag thin-film electrode material, its preparation method, and its application in electrochemical catalytic carbon dioxide reduction.

[0006] The technical solution of the present invention is as follows:

[0007] The preparation method of Cu-Ag thin film electrode material includes the following steps:

[0008] A Cu thin film is obtained by uniformly thermally depositing Cu metal onto a conductive substrate using vacuum thermal evaporation coating technology. Then, Ag ions are implanted into the Cu thin film at an implantation voltage of 10–50 kV and an Ag ion implantation amount of 2300–9000 C, resulting in Cu-Ag thin film electrode material.

[0009] Preferably, the copper source used in the vacuum thermal evaporation coating technology is a high-purity copper target with a purity of ≥99.999%.

[0010] Preferably, the Ag ion source is a high-purity silver target with a purity of ≥99.999%.

[0011] Preferably, the thermal evaporation rate is

[0012] Preferably, the Cu film thickness is More preferably

[0013] Preferably, the conductive substrate is a conventionally used conductive substrate material, such as carbon paper.

[0014] The present invention provides Cu-Ag thin film electrode materials prepared by the above preparation method.

[0015] Furthermore, the present invention provides the application of the above-mentioned Cu-Ag thin film electrode material in the electrochemical catalytic reduction of carbon dioxide to synthesize multi-carbon products.

[0016] Specifically, the Cu-Ag thin film electrode material mentioned above is used as the cathode.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) The preparation method of the present invention is simple and can be mass-produced.

[0019] (2) The Cu-Ag thin film electrode material prepared by this invention has high selectivity for the synthesis of multi-carbon products in electrochemical carbon dioxide reduction applications, with a Faraday efficiency of up to 83.5%.

[0020] (3) The Cu-Ag thin film electrode material prepared in this invention can achieve high current density in the electrochemical synthesis of multi-carbon products by carbon dioxide reduction. For example, when a voltage of -1.2V is applied (relative to a reversible hydrogen electrode), the current density can reach 445 mA / cm². 2 . Attached Figure Description

[0021] Figure 1 The X-ray diffraction patterns are of the Cu thin film electrode material in Comparative Example 3 and the Cu-Ag thin film electrode material in Example 1.

[0022] Figure 2 These are scanning electron microscope images of the Cu thin film electrode material of Comparative Example 3 and the Cu-Ag thin film electrode material of Example 1;

[0023] Figure 3 The X-ray photoelectron spectra of the Cu thin film electrode material of Comparative Example 3 and the Cu-Ag thin film electrode material of Example 1 are shown.

[0024] Figure 4 The electrochemical carbon dioxide reduction selectivity and current value of the Cu thin film electrode material of Comparative Example 3 and the Cu-Ag thin film electrode material of Example 1 at different potentials are compared.

[0025] Figure 5 This is a graph showing the selectivity data of electrochemical carbon dioxide reduction products for Cu-Ag thin film electrode materials in Comparative Example 1.

[0026] Figure 6 This is a graph showing the selectivity data of electrochemical carbon dioxide reduction products for the Cu-Ag thin film electrode material in Comparative Example 2. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0028] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] In the following examples and comparative examples, the electrochemical CO2 reduction test method is as follows:

[0030] The electrochemical carbon dioxide reduction performance of the catalytic material was tested using the Wuhan Koster electrochemical workstation. The test was conducted in a flow cell, and the electrolyte was a KOH aqueous solution with a concentration of 1 mol / L.

[0031] In typical tests, the prepared thin film material was used as the working electrode. All tests were conducted at room temperature with a CO2 gas flow rate of 40 mL / min. A platinum sheet electrode and a mercury-mercury oxide electrode were used as the counter electrode and reference electrode, respectively.

[0032] Example 1

[0033] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into Cu thin films using an ion implantation device. The implantation voltage was set to 10 kV, and the Ag ion implantation amount was controlled to be 2300 °C to obtain Cu-Ag thin film electrode materials.

[0034] Example 2

[0035] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into Cu thin films using an ion implantation device. The implantation voltage was set to 10 kV, and the Ag ion implantation amount was controlled to be 4560°C to obtain Cu-Ag thin film electrode materials.

[0036] Example 3

[0037] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into a Cu thin film using an ion implantation device. The implantation voltage was set to 10 kV, and the Ag ion implantation amount was controlled to be 9000C to obtain a Cu-Ag thin film electrode material.

[0038] Example 4

[0039] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into Cu thin films using an ion implantation device. The implantation voltage was set to 50 kV, and the Ag ion implantation amount was controlled to be 2300 °C to obtain Cu-Ag thin film electrode materials.

[0040] Example 5

[0041] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into Cu thin films using an ion implantation device. The implantation voltage was set to 50 kV, and the Ag ion implantation amount was controlled to be 4560 °C to obtain Cu-Ag thin film electrode materials.

[0042] Example 6

[0043] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into Cu thin films using an ion implantation device. The implantation voltage was set to 50 kV, and the Ag ion implantation amount was controlled to be 9000C to obtain Cu-Ag thin film electrode materials.

[0044] Comparative Example 1

[0045] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into Cu thin films using an ion implantation device. The implantation voltage was set to 70 kV and the Ag ion implantation amount was controlled to be 2300 °C to obtain Cu-Ag thin film electrode materials.

[0046] Comparative Example 2

[0047] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Ag ions were implanted into Cu thin films using an ion implantation device. The implantation voltage was set to 70 kV, and the Ag ion implantation amount was controlled to be 4560°C to obtain Cu-Ag thin film electrode materials.

[0048] Comparative Example 3

[0049] The Cu target was placed in the vacuum deposition equipment, and the deposition rate was set to [value missing]. The thickness of the evaporated Cu film is Obtain Cu thin film electrode materials.

[0050] Figure 1 The figures show the X-ray diffraction patterns of the Cu thin film electrode material in Comparative Example 3 and the Cu-Ag thin film electrode material in Example 1. As can be seen from the figures, the Cu-Ag material only exhibits the diffraction pattern of Cu metal, indicating that the introduction of Ag element did not change the crystal structure of Cu.

[0051] Figure 2 The images show scanning electron microscope (SEM) images of the Cu thin film electrode material of Comparative Example 3 and the Cu-Ag thin film electrode material of Example 1. As can be seen from the images, the obtained thin film materials are composed of nano-metal particles.

[0052] Figure 3 This is a schematic diagram of the X-ray photoelectron spectroscopy of the Cu thin film electrode material of Comparative Example 3 and the Cu-Ag thin film electrode material of Example 1. The figure shows Cu-O bonds and Ag-O bonds, indicating that there is partial oxidation on the surface of the material.

[0053] Figure 4 (a) shows the electrochemical catalytic carbon dioxide reduction product selectivity data of the Cu thin-film electrode material in Comparative Example 3; (b) shows the electrochemical catalytic carbon dioxide reduction product selectivity data of the Cu-Ag thin-film electrode material in Example 1; and (c) shows the electrochemical reaction current density of the Cu thin-film electrode material in Comparative Example 3 and the Cu-Ag thin-film electrode material in Example 1. As can be seen from Figure (b), the Cu-Ag thin-film electrode material achieves a multi-carbon product synthesis Faradaic efficiency of 83.5%, higher than the 64% Faradaic efficiency of the Cu material. Furthermore, as can be seen from Figure (c), the Cu-Ag thin-film electrode material achieves a current density of 445 mA / cm² when an applied voltage of -1.2 V (relative to the reversible hydrogen electrode). 2 The electrochemical catalytic performance of the Cu-Ag thin-film electrode materials in Examples 2-6 for carbon dioxide reduction is similar to that in Example 1.

[0054] Figure 5 The figures show the selectivity data for the electrochemical catalytic reduction of carbon dioxide products using the Cu-Ag thin-film electrode material in Comparative Example 1. As can be seen from the figures, at a potential of -0.8 V vs RHE, the optimal Faraday efficiency for the electrocatalytic reduction of multi-carbon products of CO2 is 66.40%, which is significantly lower than the optimal Faraday efficiency for multi-carbon product synthesis in Example 1.

[0055] Figure 6 The figures show the selectivity data for the electrochemical catalytic reduction of carbon dioxide products using the Cu-Ag thin-film electrode material in Comparative Example 2. As can be seen from the figures, at a potential of -0.9 V vs RHE, the optimal Faradaic efficiency for the electrocatalytic reduction of multi-carbon products of CO2 is 67.8%, which is significantly lower than the optimal Faradaic efficiency for multi-carbon product synthesis in Example 1.

Claims

1. A method for preparing Cu-Ag thin film electrode materials, characterized in that, Includes the following steps: A Cu thin film is obtained by uniformly thermally depositing Cu metal onto a conductive substrate using vacuum thermal evaporation coating technology. Then, Ag ions are implanted into the Cu thin film at an implantation voltage of 10 ~ 50 kV and an Ag ion implantation amount of 2300 ~ 9000 C to obtain Cu-Ag thin film electrode material.

2. The preparation method according to claim 1, characterized in that, The copper source used in vacuum thermal evaporation coating technology is a high-purity copper target with a purity of ≥99.999%.

3. The preparation method according to claim 1, characterized in that, The Ag ion source is a high-purity silver target with a purity of ≥99.999%.

4. The preparation method according to claim 1, characterized in that, The thermal evaporation rate is 1~15 Å / s.

5. The preparation method according to claim 1, characterized in that, The thickness of the Cu film ranges from 1000 Å to 6000 Å.

6. The preparation method according to claim 1, characterized in that, The Cu film thickness is 5000 Å.

7. The preparation method according to claim 1, characterized in that, The conductive substrate is carbon paper.

8. Cu-Ag thin film electrode material prepared by any one of the preparation methods according to claims 1 to 7.

9. The application of the Cu-Ag thin film electrode material according to claim 8 in the electrochemical catalytic reduction of carbon dioxide to synthesize multi-carbon products.

10. The application according to claim 9, characterized in that, Cu-Ag thin film electrode material was used as the cathode.

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