Pure phosphine ligand protected copper nanoclusters and applications thereof in electrocatalytic reduction of carbon dioxide
By using copper nanocluster catalysts protected by pure phosphine ligands, the problems of complex reaction pathways and low product selectivity in electrocatalytic carbon dioxide reduction technology have been solved, achieving efficient and stable carbon dioxide reduction, especially the highly selective synthesis of ethylene products, which is suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO UNIV OF SCI & TECH
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-09
AI Technical Summary
Existing electrocatalytic carbon dioxide reduction technologies suffer from complex reaction pathways, low product selectivity, and competitive hydrogen evolution reactions that affect Faraday efficiency. Furthermore, the catalysts face challenges in terms of long-term stability and industrial application.
Using copper nanoclusters protected by pure phosphine ligands as catalysts, highly efficient catalytic active centers are constructed by loading them onto carbon paper in a gas diffusion layer. The reaction conditions are optimized, and the preparation method is mild, easy to control, and yields high quantities, making it suitable for mass production.
It achieves efficient and stable carbon dioxide reduction, especially highly selective synthesis of ethylene products. The catalyst maintains good performance in multiple cycles, has low cost, and is suitable for industrial applications.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to a copper nanocluster protected by a pure phosphine ligand and its application in the electrocatalytic reduction of carbon dioxide. Background Technology
[0002] The escalating energy and environmental crisis caused by fossil fuel consumption has led to a year-on-year increase in atmospheric carbon dioxide (CO2) levels, slowly causing ecosystem collapse. Therefore, CO2 emission reduction and utilization have become a global focus. Electrocatalytic carbon dioxide reduction (eCO2RR) is an emerging technology that uses electricity to convert carbon dioxide into high-value-added chemicals and fuels (such as methane, ethylene, and ethanol), providing a new pathway for clean energy production and carbon emission mitigation. This technology uses a catalyst at the electrode interface as the core driving force, achieving efficient activation and directional conversion of inert CO2 molecules through precise control of electron and proton transfer processes. However, the multi-electron transfer process in eCO2RR leads to complex reaction pathways, and product selectivity is highly dependent on the microstructure and electronic state control capabilities of the catalyst's active sites. Furthermore, the competitive hydrogen evolution reaction (HER) significantly reduces the Faraday efficiency and energy conversion efficiency of the target product. Therefore, developing novel catalytic systems with high activity, high stability, and precise product control has become a key research focus in this field.
[0003] In recent years, researchers have made significant progress in catalyst design and reaction system optimization to address these challenges. For example, by precisely controlling the geometry and electronic density of states of metal catalysts, the carbon dioxide reduction reaction pathway can be directionally guided, achieving highly selective conversion of specific reduction products. Using nanostructured catalysts with high specific surface area and abundant active centers can significantly improve the conversion efficiency of eCO2RR. Furthermore, catalytic performance can be further optimized through small molecule modification and heteroatom doping of the catalyst surface. Among these, atomically precise nanocatalytic materials with tunable structure and composition have become a research hotspot in this field. Although industrialization challenges remain regarding large-scale preparation and long-term stability, with the deepening of interdisciplinary research, copper-based catalysts are expected to become core materials for achieving "zero-carbon chemistry," providing an efficient solution for achieving carbon neutrality. Summary of the Invention
[0004] In view of this, to address the problems in the prior art, the present invention provides a copper nanocluster protected by pure phosphine ligands and its application in the electrocatalytic reduction of carbon dioxide. The present invention has the advantages of constructing highly efficient catalytic active centers, mild and easily controllable reaction conditions, high yield of copper metal nanoclusters, and excellent catalytic performance.
[0005] The copper metal nanoclusters of this invention are nanoclusters containing 18 copper atom metal cores, with the molecular formula [Cu]. 18 H 17 (PPh2Et) 10 ]Cl.
[0006] The method for preparing copper metal nanoclusters of the present invention includes the following steps: At room temperature, Cu(C5H7O2)2 (72 mg, 0.3 mmol) was dissolved in a mixture of 15 mL dichloromethane and 5 mL methanol, initially resulting in a blue solution. The solution was vigorously stirred on a magnetic stirrer for 30 minutes. Then, PPh2Et (77 μL, 0.38 mmol) was added, and NaBH4 (60 mg, 1.6 mmol) was weighed, dissolved in ice water, and rapidly added directly to the mixture. The solution quickly turned into a blue turbidity, and the color gradually faded. The reaction proceeded at room temperature for 5 hours, during which the solution changed from blue to yellow. After 5 hours, the reaction mixture was repeatedly washed with a large amount of n-hexane using a rotary evaporator, followed by extraction with dichloromethane two to three times. Finally, the product was dissolved in dichloromethane and diffused into n-hexane. At -4... o Approximately four days after C, orange cube-shaped crystals were obtained at the bottom of the single crystal bottle, with a yield of 46% based on copper.
[0007] This invention relates to copper nanoclusters protected by pure phosphine ligands and their application in the electrocatalytic reduction of carbon dioxide.
[0008] A supported catalyst was obtained by loading copper nanoclusters protected by the pure phosphine ligands onto a gas diffusion layer of carbon paper. Using the carbon paper electrode containing the copper nanoclusters protected by the pure phosphine ligands as the working electrode, a three-electrode system consisting of a reference electrode and a counter electrode was prepared. Electrochemical reduction was carried out in a flowing liquid phase cell. The reference electrode was an Hg / HgO electrode; the counter electrode was a platinum mesh electrode.
[0009] The electrolytic cell is separated into a cathode chamber and an anode chamber by an anion exchange membrane, and the electrolyte solution used consists of an alkaline electrolyte and water.
[0010] The alkaline electrolyte is potassium hydroxide, and the concentration of the alkaline electrolyte in the electrolyte solution is 0.1~1.0 mol·L⁻¹. -1 The corresponding pH value is 13.5~14.0. The preferred electrolyte concentration is 1.0 mol·L⁻¹. -1 (pH 14.0).
[0011] In the catalytic reaction process of carbon dioxide electrocatalytic reduction, the reaction conditions can be those conventional in the field.
[0012] The voltage for the electrocatalytic reduction of carbon dioxide is -0.7 V.RHE to -1.6 V RHE The optimal value is -0.9 V. RHE to -1.6 V RHE The time for the electrocatalytic reduction of carbon dioxide is 3 to 20 minutes, preferably 8 minutes. The temperature for the electrocatalytic reduction of carbon dioxide can be room temperature, for example, 20 to 25 degrees Celsius. o C.
[0013] The supported catalyst was prepared by the following method: Copper nanoclusters protected by pure phosphine ligands were mixed with Ketjen black at a ratio of 0.1 to 2.0 and dispersed in 2 mL of isopropanol. 20 to 50 μL of 5 wt% Nafion solution was added. The mixture was then drop-coated onto 0.5 cm × 2.0 cm carbon paper and dried at room temperature for later use.
[0014] More preferably, the copper nanoclusters are mixed with Ketjen black in a ratio of 1.0, and the amount of 5 wt% Nafion is 40 μL.
[0015] The carbon paper used for the gas diffusion layer electrode is commercially available in the art. The technical parameters of the carbon paper are as follows: resistivity 5.5 mΩ·cm. 2 Density 0.83 g·cm³ -3 The thickness is 0.21 mm ± 0.01 mm; for example, the HCP 120 series. The size of the carbon paper can be cut according to experimental needs, for example (1 cm × 1 cm) to (3 cm × 3 cm), preferably 0.5 cm × 2.0 cm.
[0016] Compared with the prior art, the beneficial effects of the present invention include: 1. The method for preparing copper nanoclusters protected by pure phosphine ligands provided by the present invention has a mild reaction process, short reaction time, simple and controllable operation, high yield, easy reproducibility and scale-up, and is suitable for mass production.
[0017] 2. The copper nanoclusters protected by pure phosphine ligands prepared in this invention have small size, high chemical stability, and excellent catalytic performance, providing broad prospects for their subsequent applications.
[0018] 3. The copper nanocluster catalyst protected by pure phosphine ligands prepared in this invention has low cost and good conversion rate and catalytic selectivity in electrocatalytic hydrogenation reaction, especially for the efficient synthesis of ethylene products.
[0019] 4. In a preferred embodiment of this application, the copper nanocluster catalyst protected by pure phosphine ligands of this application can still maintain high catalytic efficiency and high stability in electrocatalytic hydrogenation reaction after 10 cycles of a single group. Attached Figure Description
[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Figure 1 This invention provides a copper nanocluster protected by pure phosphine ligands and its application in electrocatalytic carbon dioxide reduction. The single-molecule structure ball-and-stick model of the copper nanocluster determined by single-crystal diffraction experiments is shown. Figure 2 This invention provides a copper nanocluster protected by pure phosphine ligands and its application in electrocatalytic carbon dioxide reduction. The single-molecule structure filling model of the copper nanocluster determined by single-crystal diffraction experiments is shown. Figure 3 For the application of a pure phosphine ligand-protected copper nanocluster in the electrocatalytic reduction of carbon dioxide, the mass-to-charge ratio of the +1 valence monomolecule of the copper nanocluster determined by mass spectrometry experiments and the theoretical simulation spectrum are shown. Figure 4 The elemental composition spectrum of copper nanoclusters protected by pure phosphine ligands and their application in electrocatalytic carbon dioxide reduction is determined by X-ray photoelectron spectroscopy. Figure 5 The present invention relates to a copper nanocluster protected by pure phosphine ligands and its application in electrocatalytic carbon dioxide reduction. The copper nanocluster's valence state spectrum is determined by Auger electron spectroscopy. Figure 6 The characteristic absorption spectrum of copper nanoclusters protected by pure phosphine ligands and their application in electrocatalytic carbon dioxide reduction is determined by UV-Vis absorption spectroscopy experiments. Figure 7 This is a comparison of the current density of copper nanoclusters protected by pure phosphine ligands in CO2 / Ar atmosphere under linear sweep voltammetry in the electrocatalytic carbon dioxide reduction of the present invention. Figure 8 This invention relates to a copper nanocluster protected by a pure phosphine ligand and its application in electrocatalytic carbon dioxide reduction. The products of electrocatalytic CO2 reduction of the copper nanocluster at different potentials and their Faraday efficiency are shown. Figure 9 The partial current density diagram of copper nanoclusters at different potentials in a flow electrolytic cell is shown for the application of a pure phosphine ligand-protected copper nanocluster in the electrocatalytic reduction of carbon dioxide according to the present invention. Figure 10 This invention relates to a copper nanocluster protected by a pure phosphine ligand and its application in the electrocatalytic reduction of carbon dioxide. The current-time curves of the copper nanocluster at different times in a flowing electrolyzer are shown, as well as at -1.4 V. RHE Faraday efficiency plot at potential; Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0022] Unless otherwise specified, the methods for cluster preparation and electrocatalytic hydrogenation testing in this invention are conventional methods. Unless otherwise specified, all experimental materials used in this invention were commercially available.
[0023] Example 1: Preparation of copper nanoclusters protected by pure phosphine ligands The method for preparing copper nanoclusters protected by pure phosphine ligands includes the following steps: At room temperature, Cu(C5H7O2)2 (72 mg, 0.3 mmol) was dissolved in a mixture of 15 mL dichloromethane and 5 mL methanol, initially resulting in a blue solution. The solution was vigorously stirred on a magnetic stirrer for 30 minutes. Then, PPh2Et (77 μL, 0.4 mmol) was added, and NaBH4 (60 mg, 1.6 mmol) was weighed, dissolved in ice water, and rapidly added directly to the mixture. The solution quickly turned into a blue turbidity, and the color gradually faded. The reaction proceeded at room temperature for 5 hours, during which the solution changed from blue to yellow. After 5 hours, the reaction mixture was repeatedly washed with a large amount of n-hexane using a rotary evaporator, followed by extraction with dichloromethane two to three times. Finally, the product was dissolved in dichloromethane and diffused into n-hexane. At -4... o Approximately four days after starting at temperature C, orange cubic crystals were obtained at the bottom of the single-crystal flask, with a yield of 46% based on copper. The single-crystal structure diagram is shown below. Figure 1 and 2 As shown, the mass spectrum is as follows Figure 3 As shown, the X-ray photoelectron spectrum is as follows: Figure 4 As shown, Auger electron spectra are as follows Figure 5 As shown, the ultraviolet spectrum is as follows Figure 6 As shown.
[0024] Example 2: Preparation of copper nanocluster catalysts protected by pure phosphine ligands Cut carbon paper into 1.5 cm × 2.5 cm squares. Mix 2.5 mg of copper nanoclusters protected by pure phosphine ligands with 2.5 mg of Ketjen black and disperse them in 2 mL of isopropanol containing 40 μL of 5 wt% Nafion solution. Take 40 μL and drop it onto the carbon paper, with a drop area of 0.5 cm × 2.0 cm. Then dry it for later use.
[0025] Example 3: Electrocatalytic carbon reduction performance of copper nanocluster catalysts protected by pure phosphine ligands The tests were conducted using a Donghua DH7001B electrochemical workstation under a standard three-electrode system. The pure phosphine ligand-protected copper nanocluster catalyst prepared in Example 2 was used as the working electrode, Hg / HgO as the reference electrode, and a platinum mesh as the counter electrode. Electrolysis was performed in a liquid-phase flow cell, with an anion exchange membrane separating the anode and cathode chambers. The electrolyte solution for both the anode and cathode chambers was 1.0 mol·L⁻¹. -1 A potassium hydroxide solution with a pH of 14.0.
[0026] The copper nanocluster catalyst protected by pure phosphine ligands described in this invention exhibits high performance in a CO2 atmosphere at 1.0 mol·L⁻¹. -1 The eCO2RR activity of the copper-silver nanocluster catalyst material described in this invention was evaluated in a potassium hydroxide solution (pH 14.0). Figure 7 As shown, the current density in a CO2 atmosphere is greater than that in an Ar atmosphere, indicating that the copper-silver nanocluster catalyst has catalytic activity for CO2 reduction.
[0027] The copper nanoclustering agent protected by pure phosphine ligands described in this invention was subjected to oxidation in a flow cell at -0.9 V. RHE to -1.6V RHE At a given potential, the reduction product ethylene (C2H4) exhibits a volcano-like distribution. The catalytic selectivity of C2H4 ranges from 22.4% to 70.5%, particularly at -1.4 V. RHE At a given potential, it can achieve a C2H4 Faraday efficiency of 70.5%, such as Figure 8 As shown.
[0028] The copper nanoclustering agent protected by pure phosphine ligands described in this invention can achieve 300 mA·cm⁻¹ in a flow cell. -2 Even at industrial-grade current densities, it maintains a C2H4 Faraday efficiency of over 70%. For example... Figure 9 As shown, the dotted line graph represents the partial current density of various reduction products.
[0029] Example 4: Stability test of copper nanoclustering agent protected by pure phosphine ligand under carbon dioxide electroreduction cycle The tests were conducted using a Donghua DH7001B electrochemical workstation under a standard three-electrode system. The pure phosphine ligand-protected copper nanocluster catalyst prepared in Example 2 was used as the working electrode, Hg / HgO as the reference electrode, and a platinum mesh as the counter electrode. Electrolysis was performed in a liquid-phase flow cell, with an anion exchange membrane separating the anode and cathode chambers. The electrolyte solution for both the anode and cathode chambers was 1.0 mol·L⁻¹. -1 A potassium hydroxide solution with a pH of 14.0.
[0030] The experimental conditions were the same as the optimal selectivity conditions in Example 3. Ten parallel experiments were conducted using the same working electrode, ensuring identical experimental conditions each time. After each experiment, the electrolytic cell was cleaned to ensure no product residue remained. The experimental results are as follows: Figure 10 As shown, after 120 hours of electrolysis, the Faraday efficiency and total current density of C2H4 remain essentially unchanged, with the Faraday efficiency maintained between 68% and 70% and the total current density maintained at 410 mA·cm⁻¹. -2 The above indicates that the catalyst is relatively stable.
[0031] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A copper metal nanocluster material, characterized in that: The copper metal nanoclusters are nanoclusters containing 18 copper cores, with the molecular formula [Cu]. 18 H 17 (PPh2Et) 10 ]Cl.
2. The application of the copper metal nanoclusters of claim 1 in the electrocatalytic reduction of carbon dioxide.
3. The application according to claim 2, characterized in that: A carbon paper electrode containing copper nanoclusters protected by pure phosphine ligands was used as the working electrode, and electrochemical reduction was performed using a reference electrode and a counter electrode; the reference electrode was an Hg / HgO electrode; and the counter electrode was a platinum mesh electrode.
4. The application according to claim 3, characterized in that: Copper nanoclusters protected by pure phosphine ligands were mixed with Ketjen black at a ratio of 0.1 to 2.0 and dispersed in isopropanol. 20 to 50 μL of 5 wt% Nafion solution was added. The above mixed solution was drop-coated onto 0.5 cm × 2.0 cm carbon paper and dried at room temperature to serve as the working electrode.
5. The application according to claim 4, characterized in that: The copper nanoclusters protected by pure phosphine ligands were mixed with Ketjen black at a ratio of 1.0, and 40 μL of 5 wt% Nafion was used.
6. The application according to claim 4, characterized in that: The technical parameters of the carbon paper are: resistivity 5.5 mΩ·cm 2 Density 0.83 g·cm³ -3 Thickness 0.21 mm ±0.01 mm.
7. The application according to claim 3, characterized in that: The voltage for the electrocatalytic reduction of carbon dioxide is -0.7 V. RHE to -1.6 V RHE， The time for the electrocatalytic reduction of carbon dioxide is 3 to 20 minutes.
8. The application according to claim 7, characterized in that: The voltage for the electrocatalytic reduction of carbon dioxide ranges from -0.9 VRHE to -1.6 VRHE, and the reaction time is 8 minutes.
9. The application according to claim 3, characterized in that: The electrolyte solutions used in both the cathode and anode chambers are aqueous solutions of alkaline electrolytes.