A dual-atom-doped copper-based rare-element alloy catalyst for the electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method.

Abstract

The application discloses a kind of for the electrocatalytic reduction CO2 produce multi-carbon product double-atom doped copper-based rare alloy catalyst and preparation method thereof.The catalyst is prepared by selective electrochemical dealloying and metal dissolution-redeposition reconstruction strategy, realizes the construction of multiple active sites of atomic dispersion;The catalyst has three-dimensional continuous nanoporous structure, which is composed of copper matrix and uniformly doped zinc and aluminum double atoms, and shows great potential in the field of energy and environment such as electrocatalytic reduction CO2 to produce multi-carbon product and energy storage.The catalyst with multiple active sites synergistic strategy prepared by the application shows excellent performance, and provides an effective way to improve the performance of CO2 reduction reaction by balancing the kinetics between CO2 activation and H2O dissociation, which has important significance for promoting the utilization of CO2 resources and the development of clean energy technology under the goal of carbon neutralization.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials, specifically relating to a diatomic doped copper-based rare alloy catalyst for electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method. Background Technology

[0002] Utilizing renewable energy-driven CO2 electroreduction to produce high-value-added chemical precursors and synthetic fuels is a promising strategy for reducing atmospheric carbon dioxide emissions. Among the potential products, high-carbon (C₂) compounds are preferred. 2+ Substances such as ethanol, ethylene, and n-propanol have attracted much attention due to their high energy density and economic value. However, because CO2 molecules have a linear and nonpolar structure, their surface adsorption capacity is weak, and they are easily replaced by polar water molecules on the catalyst surface, resulting in low utilization of active sites. In addition, the low reactivity of CO2 itself, and the kinetic mismatch between CO2 activation and the *H generated by H2O dissociation, cause electrons and protons to tend to transfer to the hydrogen evolution reaction (HER), thus limiting the selectivity of CO2 reduction reactions.

[0003] Cu is a widely studied electrocatalyst for CO2RR, capable of converting CO2 into high-value C. 2+ However, the single metal active site on Cu has inherent catalytic limitations in multi-reactant systems because the highly mobile *H cation layer leads to preferential *H–H bonding, thereby exacerbating HER and inducing severe *CO / *H intermediate imbalance. These factors collectively limit the catalytic activity of C at high current densities. 2+ The formation of dilution alloys with dual or multiple catalytic sites opens up new possibilities for constructing model catalysts with asymmetric catalytic sites. Therefore, the rational design of electrocatalysts with multiple catalytic sites and high selectivity is essential. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a diatomic doped copper-based rare alloy catalyst for electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A diatomic doped copper-based rare-element alloy catalyst for the electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method are disclosed. The catalyst is characterized by having a three-dimensional continuous nanoporous structure, consisting of a copper matrix and zinc (Zn) and aluminum (Al) diatomic atoms doped therein; the doping amount of Zn in the diatomic matrix is ​​2.28 at%, and the doping amount of Al is 3.75 at%; the three elements Cu, Zn, and Al are uniformly distributed in the catalyst; when the catalyst is used for the electrocatalytic reduction of CO2, a flow cell reactor is used for testing, and the resulting multi-carbon products include ethylene, acetic acid, ethanol, and n-propanol.

[0007] A diatomic-doped copper-based rare-element alloy catalyst for the electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method, characterized in that the preparation method of the catalyst includes:

[0008] S1. Pure copper, pure zinc and pure aluminum are mixed in a certain proportion and then electric arc melting is carried out to prepare Cu-Zn-Al precursor alloy ingots.

[0009] S2. The precursor alloy ingot is remelted using melt spinning technology and then rapidly quenched on the surface of a rotating copper roller to obtain Cu-Zn-Al precursor alloy strips.

[0010] S3. In a 0.25 mol / L HClO4 solution, cyclic voltammetry was used to perform electrochemical dealloying and metal dissolution-redeposition reconstruction on Cu-Zn-Al precursor alloy strips to obtain Zn and Al diatomic doped Cu rare-earth alloy catalysts.

[0011] A diatomic doped copper-based rare alloy catalyst for electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method, characterized in that, in step (S1), the mixed atomic ratio of Cu, Zn and Al includes, but is not limited to, 20:40:40.

[0012] A diatomic doped copper-based rare alloy catalyst for electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method are characterized in that, in step (S2), the remelting temperature is 600~800℃ and the rotation speed of the copper roller is 1000r / min.

[0013] A diatomic-doped copper-based rare-element alloy catalyst for the electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method are disclosed. The catalyst is characterized in that, in step (S3), a carbon rod is used as the counter electrode, a Cu-Zn-Al precursor alloy strip is used as the working electrode, and Ag / AgCl is used as the reference electrode. The composition and structure are obtained periodically by cyclic voltammetry. The scanning potential E ∈ [–0.38V, 0.21V], the potential scan rate v is 500 mV / s, and the number of scan cycles is equal to 2000. All of the above potentials are relative to a reversible hydrogen electrode.

[0014] A second aspect of the present invention provides the application of a diatomic-doped copper-based rare-element alloy catalyst in the electrocatalytic reduction of CO2 to produce multi-carbon products.

[0015] The beneficial effects of this invention are: (1) This invention forms a three-dimensional continuous nanoporous copper-based rare alloy catalyst by adopting an electrochemical dealloying and metal dissolution-redeposition reconstruction path, which significantly improves the mass transfer efficiency and exposure of active sites of the material, providing an ideal reaction environment for CO2 reduction. (2) This invention provides a diatomic-doped copper-based rare-electrode alloy catalyst for the electrocatalytic reduction of CO2 to produce multi-carbon products and its preparation method. A highly efficient process for generating multi-carbon products from CO2 was achieved in a flow cell device using a copper-based rare-electrode alloy catalyst formed from a copper matrix and uniformly doped with zinc and aluminum. The catalyst exhibited a Faraday efficiency close to 91.4% and a local current density of –1.5 A·cm⁻¹. –2 The ratio of multi-carbon to single-carbon products is as high as 26.9. The proposed multi-active-site synergistic strategy broadens the understanding of high-performance catalyst development and provides an effective approach to improve the electrocatalytic reduction performance of CO2 by leveraging the kinetic balance between CO2 activation and H2O molecule decomposition. Attached Figure Description

[0016] The invention will be further illustrated with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the invention.

[0017] Figure 1 Cyclic voltammetric curves with 1 and 2000 scan cycles were obtained for the electrochemical dealloying and metal dissolution-redeposition reconstruction processes using cyclic voltammetry.

[0018] Figure 2 XRD patterns of nanoporous Zn1Al1Cu(np-Zn1Al1Cu), nanoporous Zn1Cu(np-Zn1Cu), and nanoporous Al1Cu(np-Al1Cu) catalysts prepared by the method of the present invention;

[0019] Figure 3 SEM image of the np-Zn1Al1Cu catalyst;

[0020] Figure 4 SEM-EDS image of np-Zn1Al1Cu catalyst;

[0021] Figure 5 The following are XPS plots of the np-Zn1Al1Cu catalyst: (a) Cu 2p XPS plot, (b) Cu LMM plot, (c) Cu 3p+Al 2p XPS plot and (d) Zn 2p XPS plot.

[0022] Figure 6 Product distribution diagrams and corresponding Faradaic efficiencies of (a) np-Zn1Cu, (b) np-Al1Cu and (c) np-Zn1Al1Cu catalysts at different current densities;

[0023] Figure 7 (a) Faradaic efficiency and (b) energy efficiency of np-Zn1Cu, np-Al1Cu and np-Zn1Al1Cu catalysts for producing multi-carbon products under 1 M KOH conditions;

[0024] Figure 8 The stability of multi-carbon products produced by the np-Zn1Al1Cu catalyst and the Faraday efficiency of the reduction products were investigated. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0026] Figure 1 Cyclic voltammetric curves with 1 and 2000 scan cycles are shown during the electrochemical dealloying and metal dissolution-redeposition reconstruction processes using cyclic voltammetry.

[0027] Figure 2 The XRD patterns of nanoporous Zn1Al1Cu(np-Zn1Al1Cu), nanoporous Zn1Cu(np-Zn1Cu), and nanoporous Al1Cu(np-Al1Cu) catalysts prepared by the method of the present invention are shown.

[0028] Figure 3 SEM images of the np-Zn1Al1Cu catalyst are shown.

[0029] Figure 4 The SEM-EDS image of the np-Zn1Al1Cu catalyst is shown.

[0030] Figure 5 The following diagrams are shown for the np-Zn1Al1Cu catalyst: (a) Cu 2p XPS diagram, (b) Cu LMM diagram, (c) Cu 3p+Al2p XPS diagram, and (d) Zn 2p XPS diagram. The Cu surface is enriched with electrons (Cu 2p shift negative, LMM kinetic energy increased), while Al and Zn exhibit electronic defect states (Al 2p and Zn 2p shift positive), confirming the charge redistribution effect induced by diatomic doping.

[0031] Figure 6The product distribution and corresponding Faradaic efficiencies of (a) np-Zn1Cu, (b) np-Al1Cu, and (c) np-Zn1Al1Cu catalysts at different current densities are shown. Among them, np-Zn1Al1Cu exhibits high selectivity for carbon-containing products (including CO, HCOOH, C2H4, CH4, CH3CH2OH, and C3H7OH). With increasing current density, the C... 2+ Selectivity was significantly improved, ultimately at a current density of –1.66 A·cm. –2 At that time, FE C2+ Over 91.4%;

[0032] Figure 7 The (a) Faradaic efficiency and (b) energy efficiency of np-Zn1Cu, np-Al1Cu, and np-Zn1Al1Cu catalysts for producing multi-carbon products under 1 M KOH conditions are shown, with the np-Zn1Al1Cu catalyst at C2 being the most efficient. 2+ The local current density is -1.5 A·cm. –2 It achieves its highest Faraday efficiency over a wide operating range (–1.1 to –1.74 A·cm⁻¹). -2 It maintained a C rate of over 80% within the period. 2+ Selectivity; energy efficiency reaches 35.5% when the potential reaches -1.66V (relative to the reversible hydrogen electrode);

[0033] Figure 8 The stability of the np-Zn1Al1Cu catalyst in producing multi-carbon products and the Faradaic efficiency of the reduction products were demonstrated. Among them, np-Zn1Al1Cu showed excellent long-term stability under continuous electrocatalytic CO2 reduction reaction conditions. After 100 h of electrolysis, its activity and selectivity for multi-carbon products remained almost constant.

[0034] Example 1

[0035] This example provides a method for preparing an np-Zn1Al1Cu catalyst, including the following steps;

[0036] S1. Pure copper, pure zinc, and pure aluminum are mixed in a ratio of 20:40:40 at%, and then subjected to electric arc melting to prepare Cu. 20 Zn 40 Al 40 Alloy ingot.

[0037] S2, Cu is remelted using melt spinning technology 20 Zn 40 Al 40The alloy ingot was rapidly quenched on the surface of a copper roller at a rotation speed of 100 r / min to obtain Cu. 20 Zn 40 Al 40 Precursor alloy strip.

[0038] S3. In the three-electrode system of the electrochemical workstation, with a carbon rod as the counter electrode, Cu 20 Zn 40 Al 40 The precursor alloy strip was used as the working electrode, and Ag / AgCl was used as the reference electrode. The composition and structure were obtained periodically by cyclic voltammetry in 0.25 mol / L HClO4 solution. The scanning potential E∈[–0.38V, 0.21V] of the cyclic voltammetry was in the range of 500 mV / s, and the number of scanning cycles was equal to 2000. All the above potentials were relative to the reversible hydrogen electrode.

[0039] Comparative Example 1

[0040] Preparation of np-Zn1Cu catalyst

[0041] The difference from Example 1 is that pure copper and pure zinc were mixed in a ratio of 20:80 at%, and then Cu was prepared by electric arc melting. 20 Zn 80 Alloy ingot.

[0042] Comparative Example 2

[0043] Preparation of np-Al1Cu catalyst

[0044] The difference from Example 1 is that pure copper and pure aluminum are mixed in a ratio of 20:80 at%, and then Cu is prepared by arc melting. 20 Al 80 Alloy ingot.

[0045] Example 2

[0046] Electrocatalytic CO2 reduction performance test

[0047] The catalyst slurry was prepared as follows: First, all catalysts were ground into fine powder using a mortar and pestle. Then, 10 mg of the powder was dispersed in 1 mL of a solution containing 60 μL of Nafion solution (5 wt%, Adamas, RG) and 940 μL of ethanol. The mixture was then subjected to ultrasonic treatment for 30 minutes to obtain a uniform catalyst slurry.

[0048] The preparation steps of the catalyst-supported gas diffusion electrode (GDE) are as follows: 50 μL of the obtained catalyst slurry sample is drop-coated onto carbon paper (0.5 cm²). 2The electrodes were dried overnight under vacuum on a YLS30T and used as working electrodes for the CO2 reduction reaction. All electrodes were fabricated using the same preparation method.

[0049] Electrochemical measurements were performed using a three-electrode system on a CHI-760E electrochemical workstation equipped with a CHI-680D amplifier. Catalyst-coated carbon paper, platinum foil, and Hg / HgO (1 M KOH) electrodes were used as the working electrode, counter electrode, and reference electrode, respectively. A specially designed gas diffusion flow cell was employed, with 50 mL of 1 M KOH electrolyte in each of the cathode and anode chambers, separated by an anion exchange membrane (Sustainion X37-50). CO2 was injected at a rate of 30 mL / min. –1 The gas continuously enters the cathode gas chamber at a constant flow rate, and the outflowing gas is guided to a gas chromatograph (Shimadzu, GC-2010 Plus) for analysis.

[0050] The foregoing description illustrates and describes several preferred embodiments of the invention. However, as previously stated, it should be understood that the invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A method for electrocatalytic reduction of CO2 to produce multiple carbons (C2 ... 2+ The product of the two-atom doped copper-based rare-element alloy catalyst and its preparation method are characterized in that, The catalyst possesses a three-dimensional continuous nanoporous structure, composed of a copper matrix and zinc (Zn) and aluminum (Al) diatomic atoms doped within it; the Zn doping concentration in the diatomic matrix is ​​2.28 at%, and the Al doping concentration is 3.75 at%; the Cu, Zn, and Al elements are uniformly distributed in the catalyst; when the catalyst is used for electrocatalytic reduction of CO2, a flow cell reactor is used for testing, and the obtained C 2+ This includes ethylene, acetic acid, ethanol, and n-propanol.

2. The method for electrocatalytic reduction of CO2 to C according to claim 1 2+ The product is a diatomic doped copper-based rare-element alloy catalyst and its preparation, characterized in that, The method for preparing the catalyst includes: S1. Pure copper, pure zinc and pure aluminum are mixed in a certain proportion and then electric arc melting is carried out to prepare Cu-Zn-Al precursor alloy ingots. S2. The precursor alloy ingot is remelted using melt spinning technology and then rapidly quenched on the surface of a rotating copper roller to obtain Cu-Zn-Al precursor alloy strips. S3. In a 0.25 mol / L HClO4 solution, cyclic voltammetry was used to electrochemically dealloy Cu-Zn-Al precursor alloy strips and perform surface reconstruction via metal dissolution-redeposition to obtain Zn and Al diatomic doped Cu rare-earth alloy catalysts.

3. The method according to claim 2, characterized in that, In step (S1), the mixing ratio of Cu, Zn and Al includes, but is not limited to, 20:40:40 at.

4. The method according to claim 2, characterized in that, In step (S2), the remelting temperature is 600~800℃ and the rotation speed of the copper roller is 1000 r / min.

5. The method according to claim 2, characterized in that, In step (S3), in the three-electrode system of the electrochemical workstation, a carbon rod is used as the counter electrode, a Cu-Zn-Al precursor alloy strip is used as the working electrode, and Ag / AgCl is used as the reference electrode. The composition and structure are obtained periodically by cyclic voltammetry. The scanning potential E of the cyclic voltammetry is in the range of [–0.38V, 0.21V], the potential scan rate v is in the range of 500 mV / s, and the number of scan cycles is equal to 2000. All of the above potentials are relative to the reversible hydrogen electrode.

6. The diatomic doped copper-based rare-element alloy catalyst according to any one of claims 1 to 5 for the electrocatalytic reduction of CO2 to C 2+ Applications in the product.

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