Copper oxide materials, methods of making and using the same

Abstract

This invention relates to a copper oxide material, its preparation method, and its application. The preparation method includes: mixing an inorganic base, a dispersant stabilizer, and a copper salt in water to form a raw material solution; carrying out a precipitation reaction; washing and drying the precipitated product to obtain the copper oxide material; the pH value of the raw material solution is 13.10-14; the copper salt includes copper acetate. This invention also provides the copper oxide material obtained by the above preparation method and its application in the electrocatalytic reduction of carbon dioxide. The preparation method is simple and controllable, and the prepared copper oxide material exhibits high electrocatalytic carbon dioxide reduction performance.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide electroreduction technology, and in particular to a copper oxide material, its preparation method, and its application. Background Technology

[0002] The current electrocatalytic reduction of carbon dioxide (CO2RR) faces a series of problems, including severe competition from hydrogen evolution reactions, poor chemical activity, low catalyst preparation efficiency, high cost, high energy consumption under high reaction conditions, and cumbersome preparation steps, which hinder its large-scale application. Therefore, it is particularly important to develop low-cost, high-efficiency, low-energy-consumption, and simple-to-prepare electrocatalytic materials for the reduction of carbon dioxide.

[0003] Copper is the only metallic material to date capable of reducing CO2 to high-value-added products such as ethylene and ethanol. Its oxides are highly favored by researchers due to their abundant mineral resources, low cost, and ability to produce multi-carbon products like ethylene and ethanol. Because the selectivity of pure copper oxides for ethylene ethanol strongly depends on the morphology, structure, and exposed crystal faces of the oxide, most researchers currently choose to dope copper oxides with other metals to enhance their electrocatalytic performance. However, doping not only increases production costs but also adds complexity to the preparation process. Current research on copper oxide composites mostly employs multi-step synthesis methods, which are cumbersome, energy-intensive, and lack performance, resulting in a limited understanding of copper oxide composites. Summary of the Invention

[0004] To overcome the above problems, the present invention aims to provide a copper oxide material, its preparation method, and its application. The preparation method is simple and controllable, and the resulting copper oxide material possesses both a plate-like structure and high electrocatalytic carbon dioxide reduction performance, promoting the conversion of CO2 into multi-carbon products such as ethylene and ethanol.

[0005] To achieve the above objectives, the present invention provides a method for preparing a copper oxide material, the method comprising: mixing an inorganic base, a dispersing stabilizer, and a copper salt in water to form a raw material solution, performing a precipitation reaction, washing and drying the precipitated product to obtain the copper oxide material; wherein the pH value of the raw material solution is 13.10-14; and the copper salt comprises copper acetate.

[0006] The preparation method provided by this invention utilizes a simple and controllable low-temperature wet chemical precipitation method to synthesize copper oxide materials in one step. This method promotes the formation of copper oxide catalysts by strictly controlling the solution environment (e.g., the amount of copper salt, inorganic base, and dispersant stabilizer added, the type of copper salt, and the precipitation reaction temperature). Copper salt is used as the raw material, and the dispersant stabilizer is used to control the morphology and size of the material, promoting the formation of a lamellar structure. The amount of inorganic base added, the amount of dispersant stabilizer added, the concentration of copper salt, and the type of copper salt are controlled under low-temperature reaction conditions (60-80℃) to complete the one-step precipitation process. This preparation method avoids problems such as high-temperature annealing, multi-step processes, and poor uniformity, and enriches the further research and development of copper-based electrocatalytic materials.

[0007] In the above preparation method, the amount of inorganic base added can be determined according to the pH value of the raw material solution. By controlling the amount of inorganic base added, the pH value of the raw material solution can be adjusted, thereby adjusting the morphology and catalytic performance of the copper oxide material. The pH value of the raw material solution is 13.10-14, for example, specific values ​​such as 13.10, 13.15, 13.20, 13.25, 13.30, 13.35, 13.40, 13.45, 13.50, 13.55, 13.60, 13.65, 13.70, 13.75, 13.80, 13.85, 13.90, 13.95, 14, etc., and a range with any two of the above specific values ​​as endpoints; further, it can be 13.20-14. The above pH range is beneficial for obtaining copper oxide materials with a plate-like structure.

[0008] In the above preparation method, the morphology and catalytic performance of the copper oxide material can be adjusted by controlling the amount of dispersant stabilizer. The ratio of the mass of the dispersant stabilizer to the molar amount of the copper salt is (1-10) g: (2.5-15) mmol, for example (1-10) g: (5-15) mmol, (1-5) g: (5-15) mmol, etc.

[0009] Furthermore, the ratio of the mass of the dispersant stabilizer to the molar amount of the copper salt can be (1-10) g: (5-14) mmol or (2-10) g: (2.5-15) mmol, even further it can be (1-5) g: (5-14) mmol or (2-10) g: (5-15) mmol, and still further it can be (2-10) g: (5-14) mmol. In some specific embodiments, by adopting the above ratio range, the formation of leaf-like morphology can be promoted.

[0010] In the above preparation method, the dispersion stabilizer may include polyvinylpyrrolidone (PVP), for example, it may include one or more of polyvinylpyrrolidone K12, polyvinylpyrrolidone K30, and polyvinylpyrrolidone K90.

[0011] In the above preparation method, the dispersant stabilizer can be added in the form of an aqueous solution of the dispersant stabilizer. In some specific embodiments, the concentration of the aqueous solution of the dispersant stabilizer can be 50-500 g / L.

[0012] In the above preparation method, the morphology and catalytic performance of the copper oxide material can be adjusted by controlling the precipitation reaction temperature. The precipitation reaction temperature is 60-80℃, for example, specific values ​​such as 60℃, 65℃, 70℃, 75℃, and 80℃, and a range with any two of the above specific values ​​as endpoints. In some specific embodiments, it can be further controlled to be greater than or equal to 60℃ and less than 80℃, for example, 60-79℃.

[0013] In the above preparation method, the precipitation reaction time is 1h-3h, for example, specific values ​​such as 1h, 1.5h, 2h, 2.5h, 3h, and any two of the above specific values ​​as endpoints.

[0014] In the above preparation method, the inorganic base includes potassium hydroxide and / or sodium hydroxide. In some specific embodiments, the morphology and catalytic performance of the copper oxide material can be adjusted by changing the type of inorganic base.

[0015] In the above preparation method, the inorganic base can be added in the form of an aqueous solution of the inorganic base. In some specific embodiments, the concentration of the aqueous solution of the inorganic base can be 0.1-10 mol / L.

[0016] In the above preparation method, the copper salt includes copper acetate. Compared with other soluble copper salts, copper acetate, in combination with other experimental parameters, can promote the formation of lamellar structures and further promote the formation of leaf-like structures.

[0017] In the above preparation method, the copper salt can be added in the form of an aqueous solution of copper salt. In some specific embodiments, the concentration of the aqueous solution of copper salt can be 0.1-0.3 mol / L, for example, specific values ​​such as 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, etc., and a range with any two of the above specific values ​​as endpoints; further, it can be controlled to be greater than or equal to 0.1 mol / L and less than 0.3 mol / L.

[0018] In the above preparation method, the water is used to fully dissolve the inorganic base, dispersant, and copper salt. This invention does not have a special limitation on the amount of water used, as long as the above components are fully dissolved in the raw material solution. In some specific embodiments, when at least one of the inorganic base, dispersant, and copper salt is added in the form of an aqueous solution, the water in that aqueous solution can be used as the water in the raw material solution to dissolve the above-mentioned reaction raw materials.

[0019] In some specific embodiments, the molar concentration of the copper salt in the raw material solution can be 0.05-0.2 mol / L; the mass concentration of the dispersing stabilizer in the raw material solution can be 10-60 g / L.

[0020] In the above preparation method, the process of forming the raw material solution includes: stirring and mixing the inorganic base and the dispersing stabilizer in water, and then adding the copper salt to form the raw material solution; or, stirring and mixing the copper salt and the dispersing stabilizer in water, and then adding the inorganic base to form the raw material solution.

[0021] In the above preparation method, the detergent used for washing may include ethanol and / or water. The number of washing cycles may be 3-5.

[0022] In the above preparation method, the drying temperature can be 50-70℃, and the drying time can be 10-14h.

[0023] In some specific implementations, copper oxide materials with blade-like structures can be obtained by using the following combination of parameters: The pH value of the raw material solution is 13.10-14, the mass ratio of the dispersant stabilizer to the molar amount of the copper salt is (1-10) g: (2.5-15) mmol, and the inorganic base is sodium hydroxide; Alternatively, the pH of the raw material solution is 13.10-14, and the ratio of the mass of the dispersing stabilizer to the molar amount of the copper salt is (2-10) g : (2.5-15) mmol (more specifically, (5-10) g : (2.5-15) mmol).

[0024] According to a specific embodiment of the present invention, the method for preparing the copper oxide material may include: S1. An inorganic base, a dispersing stabilizer, and a copper salt are mixed in water to form a raw material solution, wherein the pH value of the raw material solution is 13.10-14, the mass ratio of the dispersing stabilizer to the molar amount of the copper salt is (1-10)g:(2.5-15)mmol, and the mass ratio of the water to the molar amount of the copper salt is 20g:(2.5-15)mmol. S2. The raw material solution is subjected to a precipitation reaction at 60-80℃ for 1-3 hours. The precipitated product is washed and dried to obtain copper oxide material.

[0025] The present invention also provides a copper oxide material, which is obtained by the above-described method for preparing copper oxide materials.

[0026] According to a specific embodiment of the present invention, the copper oxide material has a sheet-like structure. The sheet-like copper oxide material can be used for electrocatalytic carbon dioxide reduction to obtain multi-carbon products such as ethylene and ethanol.

[0027] Furthermore, the copper oxide material can have a leaf-like structure, which can be a structure whose width gradually decreases from the middle to both ends, i.e., a sheet-like structure that is thin at both ends (or even pointed at both ends) and wide in the middle. Compared with a sheet-like structure with uniform width, this leaf-like structure can improve the electrocatalytic effect and promote the conversion of CO2 into multi-carbon products such as ethylene and ethanol. The leaf-like copper oxide material has a metal interface, which can enhance charge transfer. The thinning at both ends of the leaf-like structure or the presence of a pointed structure can accumulate electrons to further promote catalysis, further improving the ethylene-ethanol Faradaic efficiency and reducing the CO Faradaic efficiency.

[0028] According to a specific embodiment of the present invention, the copper oxide material includes copper oxide.

[0029] Furthermore, the copper oxide material may also include cuprous oxide, in which case the copper oxide material includes both copper oxide and cuprous oxide, and its chemical composition can be represented as CuO / Cu2O.

[0030] According to a specific embodiment of the present invention, the length of the copper oxide material is 380-1500 nm, more preferably 380-1020 nm, and the width is 60-600 nm, more preferably 95-200 nm.

[0031] According to a specific embodiment of the present invention, the aspect ratio of the copper oxide material can be 1.5-10.

[0032] According to a specific embodiment of the present invention, the copper oxide material may be in the form of a black powder.

[0033] This invention also provides the application of the above-mentioned copper oxide material in the electrocatalytic reduction of carbon dioxide process.

[0034] In some specific embodiments, the copper oxide material can be used as a catalyst in the aforementioned electrocatalytic reduction of carbon dioxide. For example, the copper oxide material can be used as a cathode to form a three-electrode system with a reference electrode (such as silver-silver chloride) and a counter electrode (nickel foam), using potassium hydroxide (such as a 1M potassium hydroxide solution) as the electrolyte. Carbon dioxide gas is introduced into the electrolytic cell to carry out the carbon dioxide electroreduction reaction, which can reduce carbon dioxide to multi-carbon products such as ethylene and ethanol.

[0035] In some specific embodiments, the copper oxide material of the present invention is applied to the electroreduction reaction of carbon dioxide, which can improve the Faraday efficiency of ethylene and ethanol and reduce the Faraday efficiency of CO.

[0036] The beneficial effects of this invention include: 1. The preparation method of copper oxide materials provided by this invention can solve the problems of high-temperature annealing, cumbersome multi-step process, and poor uniformity in the existing copper-based electrocatalytic materials process. This preparation method adopts a mild low-temperature wet chemical precipitation method, which is a one-step synthesis and has the advantages of simple process, low raw material cost, short preparation cycle and low energy consumption, making it suitable for large-scale preparation.

[0037] 2. The copper oxide material provided by this invention has a plate-like morphology and high performance. It exhibits excellent electrocatalytic carbon dioxide reduction to produce two-carbon products and can be applied to the field of electrocatalytic carbon dioxide reduction to reduce carbon dioxide to multi-carbon products such as ethylene and ethanol. It can improve the Faraday efficiency of ethylene and ethanol in the electroreduction of carbon dioxide, reduce hydrogen evolution side reactions, and produce high-value-added industrial raw materials while absorbing carbon dioxide. Attached Figure Description

[0038] Figure 1 These are SEM images of the copper oxide materials from Examples 1 to 5 and Comparative Examples 1 to 2.

[0039] Figure 2 This is the X-ray diffraction (XRD) curve of the copper oxide material in Example 4.

[0040] Figure 3 This is the X-ray photoelectron spectroscopy (XPS) spectrum of the copper oxide material in Example 4.

[0041] Figure 4 This is a high-magnification transmission microscope image of the copper oxide material in Example 4.

[0042] Figure 5 This is a comparison chart of the total Faradaic efficiency of the catalysts in 1M KOH solution for Example 1, Comparative Example 1, Comparative Example 2, and Example 4.

[0043] Figure 6This is a comparison graph showing the sum of the Faraday efficiencies of the catalysts in Example 1, Comparative Example 1, Comparative Example 2, and Example 4 in 1M KOH solution for ethylene and ethanol.

[0044] Figure 7 This is a comparison graph of the CO Faradaic efficiency of the catalysts in 1M KOH solution for Examples 1, Comparative Examples 1, Comparative Examples 2, and Examples 4. Detailed Implementation

[0045] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0046] The polyvinylpyrrolidone used in the following examples and comparative examples is polyvinylpyrrolidone K30.

[0047] Example 1

[0048] This embodiment provides a copper oxide material, the preparation method of which includes: Dissolve 1 g of polyvinylpyrrolidone in 20 mL of deionized water, and add 15 mL of 1 M potassium hydroxide solution. Stir at room temperature for 0.5 h to form a mixed solution. Heat the mixed solution to 60 °C, and add 50 mL of 0.1 M copper acetate solution to form a raw material solution with a pH of 13.25. Heat and stir the raw material solution at 60 °C for 1 h to carry out the precipitation reaction. After the precipitation reaction is complete, wash the precipitate 3-5 times with anhydrous ethanol and deionized water, dry at 50-70 °C for 10-14 h, and after natural cooling, grind it to obtain a copper oxide material that can be used as a catalyst, labeled CuO / Cu2O-1.

[0049] Comparative Example 1

[0050] This comparative example provides a copper oxide material, the preparation method of which includes: Dissolve 1 g of polyvinylpyrrolidone in 20 mL of deionized water, and add 9 mL of 1 M potassium hydroxide solution. Stir at room temperature for 0.5 h to form a mixed solution. Heat the mixed solution to 60 °C, and add 50 mL of 0.1 M copper acetate solution to form a raw material solution with a pH of 13.06. Heat and stir the raw material solution at 60 °C for 1 h to carry out the precipitation reaction. After the precipitation reaction is complete, wash the precipitate 3-5 times with anhydrous ethanol and deionized water, dry at 50-70 °C for 10-14 h, and after natural cooling, grind it to obtain a copper oxide material that can be used as a catalyst, labeled as CuO / Cu2O-2.

[0051] Example 2

[0052] This embodiment provides a copper oxide material, the preparation method of which includes: Dissolve 1 g of polyvinylpyrrolidone in 20 mL of deionized water, and add 15 mL of 1 M potassium hydroxide solution. Stir at room temperature for 0.5 h to form a mixed solution. Heat the mixed solution to 60 °C, and add 50 mL of 0.3 M copper acetate solution to form a raw material solution with a pH of 13.25. Heat and stir the raw material solution at 60 °C for 1 h to carry out the precipitation reaction. After the precipitation reaction is complete, wash the precipitate 3-5 times with anhydrous ethanol and deionized water, dry at 50-70 °C for 10-14 h, and after natural cooling, grind it to obtain a copper oxide material that can be used as a catalyst, labeled as CuO / Cu2O-3.

[0053] Comparative Example 2

[0054] This comparative example provides a copper oxide material, the preparation method of which includes: Dissolve 1 g of polyvinylpyrrolidone in 20 mL of deionized water, and add 15 mL of 1 M potassium hydroxide solution. Stir at room temperature for 0.5 h to form a mixed solution. Heat the mixed solution to 60 °C, and add 50 mL of 0.1 M copper nitrate solution to form a raw material solution with a pH of 13.25. Heat and stir the raw material solution at 60 °C for 1 h to carry out the precipitation reaction. After the precipitation reaction is complete, wash the precipitate 3-5 times with anhydrous ethanol and deionized water, dry at 50-70 °C for 10-14 h, and after natural cooling, grind it to obtain a copper oxide material that can be used as a catalyst, labeled CuO / Cu2O-4.

[0055] Example 3

[0056] This embodiment provides a copper oxide material, the preparation method of which includes: Dissolve 1 g of polyvinylpyrrolidone in 20 mL of deionized water, and add 15 mL of 1 M sodium hydroxide solution. Stir at room temperature for 0.5 h to form a mixed solution. Heat the mixed solution to 60 °C, and add 50 mL of 0.1 M copper acetate solution to form a raw material solution with a pH of 13.25. Heat and stir the raw material solution at 60 °C for 1 h to carry out the precipitation reaction. After the precipitation reaction is complete, wash the precipitate 3-5 times with anhydrous ethanol and deionized water, dry at 50-70 °C for 10-14 h, and after natural cooling, grind it to obtain a copper oxide material that can be used as a catalyst, labeled CuO / Cu2O-5.

[0057] Example 4

[0058] This embodiment provides a copper oxide material, the preparation method of which includes: Dissolve 5g of polyvinylpyrrolidone in 20mL of deionized water and add 15mL of 1M potassium hydroxide solution. Stir at room temperature for 0.5h to form a mixed solution. Heat the mixed solution to 60℃ and add 50mL of 0.1M copper acetate solution to form a raw material solution with a pH of 13.25. Heat and stir the raw material solution at 60℃ for 1h to carry out the precipitation reaction. After the precipitation reaction is complete, wash the precipitate with anhydrous ethanol and deionized water 3-5 times, dry at 50-70℃ for 10-14h, and after natural cooling, grind it to obtain a copper oxide material that can be used as a catalyst, labeled CuO / Cu2O-6.

[0059] Example 5

[0060] This embodiment provides a copper oxide material, the preparation method of which is similar to that of Example 1, except that the precipitation reaction temperature is changed to 80°C. The powder obtained in this experiment is a copper oxide material that can be used as a catalyst, and is labeled as CuO / Cu2O-7.

[0061] Figure 1 SEM images of the copper oxide materials from Examples 1 to 5 and Comparative Examples 1 to 2 are shown. Figure 1 It can be seen that Examples 1 and 2 have a certain lamellar morphology with relatively uniform width, and do not exhibit a distinct leaf-like structure that is thicker in the middle and thinner at both ends. Example 5 has a certain leaf-like structure with relatively pointed ends. The copper oxide materials of Examples 3 and 4 have a more regular leaf-like morphology, and it is obvious that they have a shape that is thinner at both ends and thicker in the middle. The copper oxide material of Comparative Example 1 has a cluster morphology with a high degree of randomness, and the copper oxide material of Comparative Example 2 has a rod-like or linear morphology. Neither of them has a lamellar or leaf-like structure. Among them, the length of the leaf-like copper oxide material of Example 3 is 850-1020 nm and the width is 95-180 nm. The length of the leaf-like copper oxide material of Example 4 is 380-600 nm and the width is 100-200 nm.

[0062] The results above show that the morphology of copper oxide materials can be adjusted by changing the type of copper salt and the amount of inorganic alkali (pH value of the raw material solution), thus promoting the formation of lamellar structures. Furthermore, the formation of leaf-like structures can be promoted by adjusting the type of inorganic alkali, the amount of dispersant stabilizer, and the precipitation reaction temperature.

[0063] Figure 2 This is the XRD pattern of the copper oxide material in Example 4. From... Figure 2 It can be seen that the copper oxide material prepared in Example 4 has a distinct CuO crystalline phase; Figure 3The XPS images of the copper oxide material prepared in Example 4 are shown. Image a is the high-resolution fine XPS spectrum of Cu 2p, and image b is the Cu LMM spectrum. From the Cu 2p spectrum, it can be seen that the two peaks at the electron binding energies of 933.82 eV and 953.4 eV can be attributed to Cu 2p³ / 2 and Cu 2p¹ / 2, respectively, proving the presence of Cu in the sample. + and Cu 2+ The presence of [something] can be observed in the Cu LMM spectrum, with binding energies of 568.76 eV and 573.48 eV, which belong to Cu [something]. + and Cu 2+ .

[0064] To further determine Cu + and Cu 2+ The presence of [the substance] was investigated using high-magnification transmission microscopy to characterize the copper oxide material of Example 4, yielding [results]. Figure 4 The results are shown. (By...) Figure 4 As can be seen, firstly, the blade structure with a thicker middle and thinner ends in Example 4 was perfectly fabricated, and the results can be obtained through high-magnification transmission. Figure 4 The interplanar spacing shown is 0.246 nm, belonging to the Cu2O (111) crystal plane; 0.273 nm, belonging to the CuO (110) crystal plane; and 0.237 nm, belonging to the CuO (111) crystal plane. The combined results of XRD, XPS, and high-magnification transmission microscopy confirm the presence of Cu2O and CuO in the copper oxide material of Example 4.

[0065] The copper oxide materials prepared in Example 1, Comparative Example 1, Comparative Example 2 and Example 4 were used as catalysts for carbon dioxide reduction comparative experiments.

[0066] 1. Evaluation of carbon dioxide electroreduction performance

[0067] Electrode slurry and cathode preparation: 54 mg of the catalyst to be tested, 18 mL of isopropanol (used only as a solvent, volatilized during spraying and not involved in the catalytic process), and 180 μL of Nafion (5% by mass, binder) were thoroughly ultrasonically mixed to form a catalyst slurry. The catalyst slurry was then sprayed onto a 4×4 cm hydrophobic carbon paper YSL-30T using a spray gun, with a loading of 0.5 mg / cm². 2 After spraying, it is dried in a 60℃ drying oven and then used as the cathode working electrode.

[0068] 2. Performance Testing: A 2×2cm cathode was assembled in a flow cell as the working electrode. A three-electrode system consisting of a silver-silver chloride reference electrode and a nickel foam electrode was used. Carbon dioxide gas was introduced into the flow cell electrolysis cell, and 1M KOH solution was used as the electrolyte. The performance of carbon dioxide electroreduction was tested. After a 5-minute stabilization period following the initial electrolysis, samples were collected every 7.5 minutes. The gaseous products (ethylene, CO, and hydrogen) generated by the CO2 reduction reaction (CO2RR) were analyzed using an online gas chromatograph (Agilent 8860). A thermal conductivity detector (TCD) was used to detect H2 and CO, and a flame ionization detector (FID) was used to detect hydrocarbon products (CH4 and C2H4). A standard curve was established by testing the integrated peak areas of gas standard samples of different concentrations under the same injection flow rate conditions. The quantification of gaseous products during the test was performed using the external standard method.

[0069] Faraday efficiency of gaseous products (FE) gas Calculate according to the following formula: – Total current; – Partial current of the gaseous products; - Outlet flow rate of the mixed gas (measured at reactor outlet / gas chromatograph inlet using an Agilent ADM flow meter G6691A). Atmospheric pressure; R – Ideal gas constant; T – Room temperature; - The number of electrons transferred for each product molecule produced; F – Faraday constant.

[0070] Liquid phase products were collected every 20 min and analyzed using a 400 MHz nuclear magnetic resonance spectrometer (JEOL ECS-400). 1 Quantitative analysis by ¹H-NMR. Liquid-phase products (such as HCOOH, C₂H₅OH, CH₃COOH, and CH₃CH₂CH₂OH) in the electrolyte were detected using water peak suppression technology. Quantification of the liquid-phase products was also performed using the external standard method.

[0071] Faraday efficiency (FE) of liquid products liquid Calculate according to the following formula: - Liquid phase product concentration; – Electrolyte volume; - The number of electrons transferred for each product molecule produced; F - Faraday constant; - The total amount of charge passing through the working electrode per unit time.

[0072] Figure 5 The graph shows the total Faraday efficiency of the catalysts in Example 1, Comparative Example 1, Comparative Example 2, and Example 4. Figure 6 This is a graph showing the sum of the ethylene and ethanol Faraday efficiencies of the catalysts in Example 1, Comparative Example 1, Comparative Example 2, and Example 4. Figure 7 The CO Faradaic efficiency graphs are for the catalysts of Example 1, Comparative Example 1, Comparative Example 2, and Example 4. Figure 5 , Figure 6 and Figure 7 The catalysts in Examples 1, 2, 4, and 4 correspond to samples 1, 2, 4, and 6, respectively. Figure 5 As shown, the total Faraday efficiency is the sum of the Faraday efficiencies of methanol, propanol, formic acid, ethanol, ethylene, CO, and hydrogen.

[0073] from Figure 5 It can be seen that the multi-carbon product (product with more than 1 carbon atom) in Example 4 has the highest Faraday efficiency; from Figure 6 A clearer comparison of the Faradaic efficiencies of ethylene and ethanol is possible. It can be seen that the Faradaic efficiency of ethylene and ethanol in Example 4 is the highest, reaching nearly 70%. The Faradaic efficiency of ethylene and ethanol in Comparative Example 2 is approximately 34%, in Comparative Example 1 it is 48%, and in Example 1 it is 45%. Figure 7 As can be seen from the comparison of CO faradaic efficiency among the experiments, the CO faradaic efficiency of Example 4 is about 12%, the CO faradaic efficiency of Comparative Example 2 is about 52%, the CO faradaic efficiency of Comparative Example 1 is 32%, and the CO faradaic efficiency of Example 1 is 37%.

[0074] The data above show that the copper oxide material in Example 4 exhibits the highest ethylene-ethanol Faradaic efficiency, achieving the maximum promoting effect on ethylene-ethanol production, with the leaf-like structure playing a crucial role. This indicates that catalysts with leaf-like structures demonstrate superior overall catalytic performance compared to catalysts with other morphologies.

[0075] The above results demonstrate that the copper oxide material prepared by this invention has a lamellar structure (including a leaf-like structure) and exhibits good catalytic performance, with a high Faradaic efficiency for ethylene ethanol and a low Faradaic efficiency for CO. Furthermore, the catalytic activity of the leaf-like copper oxide material prepared by this invention is higher than that of the non-leaf-like copper oxide material, especially with a significant improvement in the Faradaic efficiency for ethylene ethanol, indicating that the leaf-like structure can further enhance the catalytic activity of the material.

Claims

1. A method for preparing a copper oxide material, the method comprising: An inorganic alkali, a dispersant stabilizer, and a copper salt are mixed in water to form a raw material solution, and a precipitation reaction is carried out. The precipitated product is washed and dried to obtain the copper oxide material. The copper salt includes copper acetate; The pH value of the raw material solution is 13.10-14.

2. The production method according to claim 1, wherein The ratio of the mass of the dispersant stabilizer to the molar amount of the copper salt is (1-10) g : (2.5-15) mmol; Preferably, the ratio of the mass of the dispersing stabilizer to the molar amount of the copper salt is (1-10) g : (5-14) mmol; More preferably, the ratio of the mass of the dispersing stabilizer to the molar amount of the copper salt is (1-5) g : (5-14) mmol.

3. The production method according to claim 1, wherein, The precipitation reaction is carried out at a temperature of 60-80℃ for 1-3 hours.

4. The production method according to claim 1, wherein The dispersion stabilizer includes polyvinylpyrrolidone; And / or, the inorganic base includes potassium hydroxide and / or sodium hydroxide.

5. The production method according to claim 1, wherein The process of forming the raw material solution includes: stirring and mixing the inorganic base and the dispersing stabilizer in water, and then adding the copper salt to form the raw material solution; Alternatively, the copper salt and the dispersing stabilizer can be mixed in water by stirring, and then the inorganic base can be added to form the raw material solution.

6. The production method according to claim 1, wherein The ratio of the mass of the dispersing stabilizer to the molar amount of the copper salt is (1-10) g : (2.5-15) mmol, and the inorganic base is sodium hydroxide; Alternatively, the ratio of the mass of the dispersing stabilizer to the molar amount of the copper salt is (2-10) g : (2.5-15) mmol.

7. A copper oxide material, obtained by the preparation method of the copper oxide material according to any one of claims 1-6; Preferably, the copper oxide material has a sheet-like structure; more preferably, the copper oxide material has a blade-like structure.

8. The cuprate oxide material of claim 7, wherein, The copper oxide material includes copper oxide; Preferably, the copper oxide material further includes cuprous oxide.

9. The copper oxide material of claim 7, wherein, The copper oxide material has a length of 380-1500 nm and a width of 60-600 nm; Preferably, the width of the copper oxide is 95-600 nm.

10. The application of the copper oxide material according to any one of claims 7-9 in the electrocatalytic reduction of carbon dioxide process.

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