Amorphous nano-metallic copper catalyst, and preparation method and application thereof
Amorphous nano-metallic copper catalysts were prepared by supercritical carbon dioxide-electroreduction method, which solved the problem of poor selectivity of existing copper-based catalysts in the conversion of carbon dioxide to polyols, and achieved efficient conversion and stable production of polyols.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INST OF CHEM CHINESE ACAD OF SCI
- Filing Date
- 2023-02-16
- Publication Date
- 2026-05-29
AI Technical Summary
Existing copper-based catalysts exhibit poor selectivity when converting carbon dioxide into polyols. This is mainly because the exposed crystal faces are primarily Cu(100) and Cu(111), resulting in higher selectivity for ethylene and methane, but poorer selectivity for polyols.
Amorphous nano-copper catalysts were prepared using a supercritical carbon dioxide-electroreduction method. By transforming crystalline nano-copper into an amorphous structure, the catalyst's activation capacity for carbon dioxide and the coverage of the intermediate product carbon monoxide were increased, thereby improving the selectivity of polyols.
The catalyst achieved high selectivity and good stability in the efficient conversion of carbon dioxide into polyols. The Faraday efficiency of the catalyst in the gas diffusion electrode flow cell for polyols was 55%, the current density was 320 mA cm⁻², and the catalyst maintained good stability for 50 consecutive hours.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of chemical engineering, specifically relating to an amorphous nano-metallic copper catalyst, its preparation method, and its application. Background Technology
[0002] With the massive consumption of fossil fuels, the concentration of carbon dioxide in the atmosphere has risen sharply, exceeding 400 ppm, causing a series of environmental and social problems over the past few decades. The efficient conversion of carbon dioxide into high-value-added chemicals is a crucial problem that urgently needs to be solved worldwide, and electrocatalytic conversion is one of the most promising methods.
[0003] Electrochemical methods can convert carbon dioxide into various products, including carbon monoxide, hydrocarbons, acids, and alcohols. In recent years, significant progress has been made in the research of electrochemical catalytic conversion of carbon dioxide. By designing different catalytic materials, electrolytes, and reaction devices, the selectivity and activity of electrocatalytic carbon dioxide reduction can be significantly improved. Compared to gaseous products, liquid products have higher energy density and are easier to transport, making them of significant research and practical value. Among these, polyols such as ethanol and propanol are not only commonly used solvents and fuels but also important industrial chemicals. Therefore, utilizing electrochemical methods to convert carbon dioxide into polyols is of great significance.
[0004] Copper-based catalysts are considered the most promising metal catalysts for converting carbon dioxide into multi-carbon products. Over the past few decades, various copper-based catalysts have been designed to improve the selectivity of multi-carbon products. However, the products are mainly gaseous products such as ethylene, with poor selectivity for multi-carbon alcohols. This is primarily because conventional copper catalysts expose mainly Cu(100) and Cu(111) crystal planes, which exhibit high selectivity for ethylene and methane but poor selectivity for multi-carbon alcohols. Therefore, designing and developing novel, efficient, and stable electrode materials capable of efficiently converting carbon dioxide into multi-carbon alcohols is a very meaningful research topic and a pressing problem that the scientific and industrial communities urgently need to solve. Summary of the Invention
[0005] In view of this, one of the objectives of this invention is to provide an amorphous nano-copper catalyst. This material not only efficiently converts carbon dioxide into polyols, but also exhibits good stability.
[0006] The amorphous nano-copper catalyst was prepared by supercritical carbon dioxide-electroreduction method, following the steps described below:
[0007] 1) Dissolve a copper compound in oleylamine, add ascorbic acid to the resulting solution, sonicate to dissolve, and heat to react, to obtain crystalline nano-metallic copper; wash the crystalline nano-metallic copper with a solvent and disperse it in methanol to obtain a crystalline nano-metallic copper methanol dispersion;
[0008] 2) The crystalline nano-metallic copper methanol dispersion was transferred to a high-pressure reactor, and high-pressure carbon dioxide was added to the reactor. The mixture was stirred and reacted at a certain temperature for a certain time. The pressure was then released to obtain amorphous copper oxide.
[0009] 3) The amorphous copper oxide is composited on carbon paper as a working electrode, and after electrochemical reduction, an amorphous nano-metallic copper catalyst is obtained.
[0010] In step 1) of the above method, the copper compound may be selected from at least one of the following: copper sulfate (CuSO4), copper nitrate (CuNO3), copper chloride (CuCl2), copper acetate (Cu(CH3COO)2), copper acetylacetonate (Cu(acac)2), preferably copper acetylacetonate;
[0011] The mass ratio of the copper compound to ascorbic acid can be 1:1 to 1:10, preferably 1:5;
[0012] The reaction temperature can be 100-200℃, preferably 130℃;
[0013] The reaction time can be 2-8 hours, preferably 4 hours.
[0014] The solvent is selected from any of the following mixtures: ethanol / n-hexane, ethanol / cyclohexane, methanol / n-hexane, methanol / cyclohexane mixture, preferably ethanol / n-hexane; the volume ratio of the two in the above mixture can be 1:10-10:1, specifically 1:1.
[0015] The purpose of the washing is to remove oleylamine and unreacted substances, and the washing is performed at least three times, such as five times.
[0016] In step 2) of the above method, the carbon dioxide pressure can be 8-20 MPa, preferably 8 MPa;
[0017] In step 2) of the above method, the reaction temperature can be 35-65℃, preferably 35℃;
[0018] In step 2) of the above method, the reaction time can be 4-16 hours, preferably 12 hours;
[0019] In step 3) of the above method, the electrode is prepared by adding a certain amount of Nafion solution to a methanol dispersion of amorphous copper oxide, mixing it evenly, and then dripping it onto commercial carbon paper and drying it.
[0020] The amount of Nafion solution used in each milliliter of methanol dispersion of amorphous copper oxide can be 10 μl to 40 μl, preferably 20 μl.
[0021] The Nafion (perfluorosulfonic acid polymer) solution may specifically be a Nafion D-521 dispersion (CAS No.: 31175-20-9).
[0022] The concentration of amorphous copper oxide in the methanol dispersion of the amorphous copper oxide was 8 mg / ml. -1 .
[0023] More specifically, the electrode is prepared by adding Nafion D-521 dispersion (5wt%) to a methanol dispersion of amorphous copper oxide, ultrasonically mixing it evenly, and then drop-coating it onto a 2cm×2cm hydrophobic carbon paper. After drying, a 1cm×2cm piece of carbon paper is cut out as the working electrode.
[0024] The electrochemical reduction method is the voltammetric method, with a potential range of -0.5V to -2.0vs.RHE and a scan rate of 10-100mVs. -1 Preferably 50mVs -1 .
[0025] In the electrochemical reduction described above, the composite carbon paper serves as the working electrode, nickel foam as the counter electrode, and a silver / silver chloride electrode as the reference electrode. A 1 mol / L KOH solution is used as the cathode and anolyte, and the electrochemical reduction is carried out in a flowing electrolytic cell.
[0026] The second objective of this invention is to provide the application of amorphous nano-metallic copper catalysts in the electrochemical catalytic reduction of carbon dioxide to prepare polyols.
[0027] The electrochemical catalytic system includes the above-mentioned electrode material (amorphous nano-metallic copper catalyst) and a reaction electrolyte. The reaction electrolyte is selected from one or more of the following electrolyte solutions: NaHCO3 solution, KHCO3 solution, CsHCO3 solution, Na2CO3 solution, K2CO3 solution, NaCl solution, KCl solution, NaOH solution, KOH and CsOH solution, specifically KOH solution.
[0028] The molar concentration of the electrolyte solution can be 0.1-5.0 mol / L, specifically 1 mol / L.
[0029] The application of the aforementioned electrode materials and electrochemical catalytic systems in the electrochemical catalytic conversion of carbon dioxide to synthesize polyols also falls within the scope of protection of this invention.
[0030] The present invention also provides a method for the electrochemical catalytic conversion of carbon dioxide to synthesize polyols.
[0031] The method for synthesizing polyols by electrochemical catalytic conversion of carbon dioxide provided by the present invention includes the following steps: in an electrochemical catalytic system, using carbon dioxide as a raw material, the electrochemical reaction of carbon dioxide is catalyzed through the action of electrode materials and electrolyte to synthesize polyols.
[0032] In the above method, the electrode material includes a cathode material and an anode material;
[0033] The cathode material is the amorphous nano-metallic copper catalyst prepared in this invention;
[0034] The anode material includes an alloy or compound composed of one or more of Ir, Ru, Fe, Co, Ni, Cu, C and Mn.
[0035] In the above method, the electrolyte is selected from one or more of the following electrolyte solutions: NaHCO3 solution, KHCO3 solution, CsHCO3 solution, Na2CO3 solution, K2CO3 solution, NaCl solution, KCl solution, NaOH solution, KOH and CsOH solution, specifically KOH solution.
[0036] The molar concentration of the electrolyte solution can be 0.1-5.0 mol / L, specifically 1 mol / L.
[0037] Furthermore, the electrochemical reaction system is a three-electrode electrochemical reaction system; the three-electrode electrochemical reaction system includes a working electrode, a counter electrode, a reference electrode, a diaphragm, and an electrolyte;
[0038] The working electrode is an amorphous nano-metallic copper catalyst prepared in this invention;
[0039] The counter electrode includes one or more of the following: nickel electrode, carbon electrode, platinum electrode, glassy carbon electrode, platinum-carbon electrode, and platinum mesh electrode;
[0040] The reference electrode includes a silver / silver chloride reference electrode;
[0041] The membrane is an anion exchange membrane, specifically such as the Fumapem FAA-3-50 membrane.
[0042] In the above method, the flow rate of the carbon dioxide gas is 10-50 sccm, specifically 20 sccm.
[0043] In the above method, the reaction potential can be -0.4 to -2.0 V vs. RHE, specifically -0.5 to -1.0 V vs. RHE;
[0044] The reaction time can be 0.5-120 hours, specifically 1-10 hours, 1-5 hours or 3 hours.
[0045] The reaction can be carried out in a commercial gas diffusion electrode flow electrolyzer.
[0046] The products of the reaction include ethanol, propanol, acetic acid, ethylene, carbon monoxide, methane, and hydrogen, with ethanol and propanol being the main products.
[0047] This invention provides an amorphous nano-copper catalyst, its preparation method, and its application in the electroreduction of carbon dioxide. This invention innovatively utilizes supercritical carbon dioxide and electroreduction to transform crystalline nano-copper into an amorphous nano-copper catalyst. The amorphous structure increases the catalyst's activation capacity for carbon dioxide and simultaneously increases the coverage of the intermediate carbon monoxide on the catalyst, improving the adsorption of multi-carbon oxygen-containing intermediates by the copper catalyst in the electroreduction of carbon dioxide, thus achieving high selectivity for the conversion of carbon dioxide to polyols.
[0048] Experimental results show that the amorphous nano-copper catalyst provided by this invention exhibits a Faraday efficiency of 55% and a current density of 320 mA / cm² for polyols in a gas diffusion electrode flow cell. -2 Furthermore, the current density and selectivity for polyols did not change significantly over a continuous 50-hour period. This indicates that the amorphous nano-copper catalyst and the method for preparing polyols described in this invention have good stability and are suitable for commercial applications. Attached Figure Description
[0049] Figure 1 The image is a scanning electron microscope (SEM) or transmission electron microscope (TEM) image of R-8-Cu-12.
[0050] Figure 2 High-resolution TEM (HR-TEM) image of R-8-Cu-12;
[0051] Figure 3 X-ray fine structure (XAFS) image of R-8-Cu-12;
[0052] Figure 4 The product distribution diagram of the electrocatalytic reduction of carbon dioxide by the R-8-Cu-12 catalyst at different voltages;
[0053] Figure 5 The current density diagram of R-8-Cu-12 catalyst at different voltages;
[0054] Figure 6 The graph shows the results of the long-term stability test of R-8-Cu-12. Detailed Implementation
[0055] The present invention will be described below through specific embodiments, but the present invention is not limited thereto.
[0056] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.
[0057] This invention provides an amorphous nano-copper catalyst that can not only efficiently convert carbon dioxide into polyols, but also has good stability.
[0058] The amorphous nano-copper catalyst was prepared by a supercritical carbon dioxide-electroreduction method comprising the following steps:
[0059] 1) Dissolve copper compounds in oleylamine, add ascorbic acid to the resulting solution, sonicate to dissolve, heat to a certain temperature and react for a certain time, cool to room temperature, wash five times with a mixed solution, and disperse the obtained crystalline nano-metallic copper in a methanol solution;
[0060] 2) The crystalline nano-metallic copper methanol dispersion obtained above was transferred to a high-pressure reactor, high-pressure carbon dioxide was added to the reactor, and the mixture was stirred at a certain temperature for a certain time. The pressure was then released to obtain amorphous copper oxide.
[0061] 3) The amorphous copper oxide obtained in the above steps is composited on carbon paper as an electrode, and after electrochemical reduction, an amorphous nano-metallic copper catalyst is obtained.
[0062] In step 1) of the above method, the copper compound may be selected from one of copper sulfate (CuSO4), copper nitrate (CuNO3), copper chloride (CuCl2), copper acetate (Cu(CH3COO)2), and copper acetylacetonate (Cu(acac)2), preferably copper acetylacetonate;
[0063] The mass ratio of the copper compound to ascorbic acid can be 1:1 to 1:10, preferably 1:5;
[0064] The reaction temperature can be 100-200℃, preferably 130℃;
[0065] The reaction time can be 2-8 hours, preferably 4 hours;
[0066] The mixture may be ethanol / n-hexane, ethanol / cyclohexane, methanol / n-hexane, or a methanol / cyclohexane mixture, preferably ethanol / n-hexane;
[0067] In step 2), the carbon dioxide pressure can be 8-20 MPa, preferably 8 MPa;
[0068] The reaction temperature can be 35-65℃, preferably 35℃;
[0069] The reaction time can be 4-16 hours, preferably 12 hours;
[0070] In step 3), the specific method for laminating the obtained material onto carbon paper is as follows: a certain amount of Nafion solution is added to the methanol dispersion obtained in step 2, and then drop-coated onto commercial carbon paper.
[0071] The amount of Nafion used can be 10 μl / ml to 40 μl / ml, preferably 20 μl / ml.
[0072] The electrochemical reduction method is the voltammetric curve method, with a potential range of -0.5V to -2.0V vs. RHE.
[0073] The second objective of this invention is to provide the application of amorphous nano-metallic copper catalysts in the electrocatalytic reduction of carbon dioxide to prepare polyols.
[0074] The electrochemical catalytic system includes the above-mentioned electrode material and reaction electrolyte. The reaction electrolyte includes one or more of the following: NaHCO3 solution, KHCO3 solution, CsHCO3 solution, Na2CO3 solution, K2CO3 solution, NaCl solution, KCl solution, NaOH solution, KOH and CsOH solution, specifically KOH solution.
[0075] The molar concentration of the electrolyte can be 0.1-5.0 mol / L, specifically 1 mol / L;
[0076] The application of the aforementioned electrode materials and electrochemical catalytic systems in the electrochemical catalytic conversion of carbon dioxide to synthesize polyols also falls within the scope of protection of this invention.
[0077] The present invention also provides a method for the electrochemical catalytic conversion of carbon dioxide to synthesize polyols.
[0078] The method for synthesizing polyols by electrochemical catalytic conversion of carbon dioxide provided by the present invention is as follows: in an electrochemical catalytic system, carbon dioxide is used as a raw material, and the electroreduction reaction of carbon dioxide is catalyzed through the action of electrode materials and electrolyte to synthesize polyols.
[0079] In the above method, the reaction potential can be -0.4 to -2.0 V vs. RHE, specifically -0.5 to -1.2 V vs. RHE;
[0080] The reaction time can be 0.5-120 hours, specifically 1-10 hours, 1-5 hours or 3 hours.
[0081] The reaction can be carried out in a commercial gas diffusion electrode flow electrolyzer.
[0082] The products of the reaction include ethanol, propanol, acetic acid, ethylene, carbon monoxide, methane, and hydrogen, with ethanol and propanol being the main products.
[0083] This invention provides an amorphous nano-copper catalyst, its preparation method, and its application in the electroreduction of carbon dioxide. This invention innovatively utilizes supercritical carbon dioxide and electroreduction to transform crystalline nano-copper into an amorphous nano-copper catalyst. The amorphous structure increases the catalyst's activation capacity for carbon dioxide and simultaneously increases the coverage of the intermediate carbon monoxide on the catalyst, improving the adsorption of multi-carbon oxygen-containing intermediates by the copper catalyst in the carbon dioxide electroreduction and achieving high selectivity for the conversion of carbon dioxide to polyols.
[0084] Experimental results show that the amorphous nano-copper catalyst provided by this invention exhibits a Faraday efficiency of 55% and a current density of 320 mA / cm² for polyols in a gas diffusion electrode flow cell. -2 Furthermore, the current density and selectivity for polyols did not change significantly over a continuous 50-hour period. This indicates that the amorphous nano-copper catalyst and the method for preparing polyols described in this invention have good stability and are suitable for commercial applications.
[0085] Example 1: Preparation and characterization of amorphous nano-copper catalysts
[0086] Take the preparation of R-8-Cu-12 catalyst as an example.
[0087] 1) Preparation of 8-Cu-12 catalyst.
[0088] First, 44 mg of copper acetylacetonate was dissolved in 20 mL of oleylamine, then 210 mg of ascorbic acid was added, and the solution was sonicated to form an orange solution. The solution was kept at 130 °C for 4 h, then cooled to room temperature. Subsequently, crystalline nano-copper was obtained by centrifugation, washed multiple times with an ethanol-n-hexane solution (volume ratio 1:1), and then dispersed in 2 mL of methanol. The solution was then transferred to an autoclave, purged with high-pressure carbon dioxide at 8 MPa and 35 °C, and stirred for 12 h. The carbon dioxide pressure was then released to atmospheric pressure to obtain an 8-Cu-12 catalyst dispersed in the methanol solution (where 8 represents the pressure of 8 MPa and 12 represents the stirring time of 12 h; the meaning of the numbers in the following catalyst descriptions can be found in the 8-Cu-12 description). By adjusting the CO2 pressure and reaction time, catalysts of 8-Cu-4, 8-Cu-16, 10-Cu-4, 10-Cu-12, 10-Cu-16, 12-Cu-4, 12-Cu-12 and 12-Cu-16 were obtained, respectively.
[0089] 2) Electrochemical reduction preparation of R-8-Cu-12.
[0090] Add 40 μL of Nafion D-521 dispersion (5 wt%) (brand: Alpha, catalog number: 042117) to 2 ml of 8-Cu-12 methanol dispersion (8 mg / ml). -1 In this process, the material was ultrasonically mixed and then drop-coated onto 2cm × 2cm hydrophobic carbon paper. After drying, 1cm × 2cm pieces of carbon paper were cut out to serve as the working electrode. Nickel foam was used as the counter electrode, and a silver / silver chloride electrode was used as the reference electrode. Electrochemical reduction was carried out in a flowing electrolytic cell using 1mol / L KOH solution as both the cathode and anolyte. The reaction was analyzed using a voltammetric method, with an applied voltage range of -0.5 to -2.0V vs. RHE and a scan rate of 50mVs. -1 After three cycles of reaction, the amorphous nano-metallic copper catalyst (R-8-Cu-12) supported on the carbon paper gas diffusion layer of the present invention is obtained.
[0091] We systematically characterized the R-8-Cu-12 catalyst. Transmission electron microscopy (TEM) images showed that R-8-Cu-12 particles are approximately 40 nm in diameter and possess a core-shell structure. Figure 1 High-resolution TEM (HR-TEM) images show that the core structure of R-8-Cu-12 is crystalline copper, while the shell structure is amorphous. Figure 2 The X-ray fine spectrum (XAFS) indicates that R-8-Cu-12 is metallic copper with a low coordination number. Figure 3 ).
[0092] Example 2: Electrochemical catalytic conversion of carbon dioxide
[0093] A carbon paper gas diffusion layer loaded with the R-8-Cu-12 catalyst obtained in Example 1 of this invention was used as the working electrode, nickel foam as the counter electrode, and a silver / silver chloride electrode as the reference electrode. A 1 mol / L KOH solution was used as both the cathode and anolyte. The carbon dioxide electroreduction performance was tested in a flowing electrolytic cell. During the test, the carbon dioxide flow rate was maintained at 20 ccm, and the electrolyte flow rate was maintained at 10 ml / min. A Fumapem FAA-3-50 membrane was used as the anion exchange membrane to separate the cathode and anolyte. A constant voltage method was used, with the applied voltage range being -0.5 to -1.2 V vs. RHE. Gaseous products were collected using a gas bag and analyzed using a gas chromatograph (GC, HP 4890D). Liquid products were analyzed using nuclear magnetic resonance (NMR). 1 The analysis was performed using HNMR (Bruker Avance III 400HD).
[0094] See Figure 4 , Figure 4The Faraday efficiency of each product in the electroreduction of carbon dioxide catalyzed by the R-8-Cu-12 catalyst in a flowing electrolyzer is given.
[0095] Figure 4 The figure shows the product distribution of the electrocatalytic reduction of carbon dioxide by the R-8-Cu-12 catalyst at different voltages. As can be seen from the figure, the catalyst of this invention exhibits excellent selectivity for polyols. The Faraday efficiency for ethanol and propanol can reach 55% at a potential of -0.9 V vs. RHE.
[0096] See Figure 5 , Figure 5 The current density-potential curve of the R-8-Cu-12 catalyst provided by this invention catalyzing the electroreduction reaction of carbon dioxide in a flowing electrolyzer.
[0097] Figure 5 The figure shows the current density of the electrocatalytic reduction of carbon dioxide under different voltages in Example 2. The R-8-Cu-12 catalyst obtained in Example 2 exhibits a high current density during the reaction, reaching 320 mA / cm² at -0.9 V vs. RHE. -2 .
[0098] Example 3: Study on the stability of the catalyst
[0099] The long-term stability of R-8-Cu-12 can be evaluated by conducting the reaction at a potential of -0.9V vs. RHE for 50 hours. See [link to relevant documentation]. Figure 6 , Figure 6 The stability test curves of the amorphous nano-copper catalyst provided in this invention are shown after 50 hours. We found that neither the current density nor the Faraday efficiency of the polyols showed significant changes. Figure 6 This indicates that the catalyst has good electrochemical stability and significant industrialization value.
Claims
1. A method for preparing an amorphous nano-copper catalyst, comprising the following steps: 1) Dissolve a copper compound in oleylamine, add ascorbic acid to the resulting solution, sonicate to dissolve, and heat to react, to obtain crystalline nano-metallic copper; wash the crystalline nano-metallic copper with a solvent and disperse it in methanol to obtain a crystalline nano-metallic copper methanol dispersion; 2) The crystalline nano-metallic copper methanol dispersion was transferred to a high-pressure reactor, and high-pressure carbon dioxide was added to the reactor. The mixture was stirred and reacted at a certain temperature for a certain time. The pressure was then released to obtain amorphous copper oxide. 3) The amorphous copper oxide is composited on carbon paper as a working electrode, and after electrochemical reduction, an amorphous nano-metallic copper catalyst is obtained. In step 2), the carbon dioxide pressure is 8-20 MPa.
2. The preparation method according to claim 1, characterized in that: In step 1), the copper compound is selected from at least one of the following: copper sulfate, copper nitrate, copper chloride, copper acetate, and copper acetylacetone; The mass ratio of the copper compound to ascorbic acid is 1:1 to 1:10; The reaction temperature is 100-200°C. o C; The reaction time is 2-8 hours; The washing solvent is selected from any of the following mixtures: ethanol / n-hexane, ethanol / cyclohexane, methanol / n-hexane, and methanol / cyclohexane mixture.
3. The preparation method according to claim 2, characterized in that: In step 1), the copper compound is copper acetylacetonate; The washing solvent is selected from the following mixture: ethanol / n-hexane, wherein the volume ratio of the two solvents in the mixture is 1:10-10:
1.
4. The preparation method according to any one of claims 1-3, characterized in that: In step 2), the reaction temperature is 35-65°C. o C; The reaction time is 4-16 hours.
5. The preparation method according to any one of claims 1-3, characterized in that: In step 3), the electrode is prepared by adding Nafion solution to a methanol dispersion of amorphous copper oxide, mixing it evenly, and then drop-coating it onto commercial carbon paper and drying it. The amount of Nafion solution used in each milliliter of methanol dispersion of amorphous copper oxide is 10 μl - 40 μl. The concentration of amorphous copper oxide in the methanol dispersion of the amorphous copper oxide was 8 mg·ml. -1 .
6. The preparation method according to any one of claims 1-3, characterized in that: In step 3), the electrochemical reduction method is the voltammetric method, with a potential range of -0.5V to -2.0 vs. RHE and a scan rate of 10-100 mV·s. -1 .
7. The amorphous nano-metallic copper catalyst prepared by the method according to any one of claims 1-6.
8. The application of the amorphous nano-metallic copper catalyst according to claim 7 in the electrocatalytic reduction reaction of carbon dioxide.
9. A method for synthesizing polyols by electrochemical catalytic conversion of carbon dioxide, comprising the following steps: using carbon dioxide as a raw material, the polyols are synthesized by reaction through the action of electrode materials and electrolyte; The electrode material includes a cathode material; the cathode material is the amorphous nano-metallic copper catalyst as described in claim 7.
10. The method according to claim 9, characterized in that: The electrode material also includes an anode material; The anode material includes an alloy or compound composed of one or more of Ir, Ru, Fe, Co, Ni, Cu, C and Mn; Alternatively, the electrolyte is selected from one or more of the following electrolyte solutions: NaHCO3 solution, KHCO3 solution, CsHCO3 solution, Na2CO3 solution, K2CO3 solution, NaCl solution, KCl solution, NaOH solution, KOH and CsOH solution; the molar concentration of the electrolyte solution is 0.1-5.0 mol / L; Alternatively, the flow rate of the carbon dioxide gas is 10–50 sccm; Alternatively, the reaction potential is -0.4 to -2.0 V. vs. RHE; the reaction time is 0.5-120 h; Alternatively, the reaction may be carried out in a commercial gas diffusion electrode flow electrolyzer.
11. The method according to claim 9 or 10, characterized in that: The polyols include ethanol and propanol.