A preparation method of a copper-based catalyst capable of achieving industrial ampere-level current density, and products and applications thereof

Abstract

The application discloses a preparation method of a copper-based catalyst capable of realizing industrial ampere-grade current density, and the method comprises the following steps: (1) dissolving a copper salt and an alkaline substance to form a mixed solution; (2) performing hydrothermal treatment on the mixed solution obtained in the step (1) to obtain a copper precursor; and (3) performing calcination treatment on the copper precursor prepared in the step (2) to obtain the copper-based catalyst. The application further discloses the copper-based catalyst prepared by the above preparation method and application of the copper-based catalyst in an electro-reduction CO reaction. The preparation method is simple and efficient, and the copper-based catalyst prepared by the preparation method has high active electro-reduction CO capacity under industrial ampere-grade current density.

Description

Technical Field

[0001] This invention relates to the fields of materials synthesis and electrocatalysis, specifically to a method for preparing a copper-based catalyst capable of achieving industrial-grade ampere-level current density, as well as its products and applications. Background Technology

[0002] Excessive emissions of greenhouse gases such as carbon dioxide (CO2) have led to increasingly serious environmental problems. Solving the CO2 problem is beneficial for alleviating energy issues and producing chemicals with high added value.

[0003] Compared to traditional thermocatalytic CO2 reduction, the electrocatalytic reduction of CO2 (CO2RR) can directly use water as a hydrogen source and achieve the co-electrolytic reduction of CO2 and H2O under mild conditions through renewable electricity. This enables the production of high-energy-density and high-value-added multi-carbon (C2) products. 2+ It has certain advantages in terms of products. To avoid the tendency for carbonate deposition (2OH⁻) to occur in the alkaline flow electrolysis cell system during electrocatalytic CO₂ reduction reaction. – +CO2=CO3 2– +H2O) and C 2+ The problem of low Faraday efficiency in CO2-C products is being addressed through ongoing research. 2+ The reduction reaction proceeds in two steps. Carbon monoxide (CO) produced from CO2 is used as a raw material, and then converted to C via an electroreduction reaction (CORR). 2+ Products. The use of gas diffusion electrodes (GDEs) has increased the current density of CO2RR / CORR from tens of milliamperes per square centimeter to hundreds of milliamperes per square centimeter. However, at high current densities, the competing hydrogen evolution reaction (HER) is more likely to occur, which often reduces the selectivity and stability of the catalyst and leads to a loss of energy efficiency. Therefore, developing inexpensive, high-efficiency catalysts for the electrochemical conversion of CO at industrial ampere-level current densities that can suppress HER is key to industrial scalability.

[0004] Copper and its compounds remain the most effective materials for the electroreduction of CO to C. 2+ The electrocatalyst for the product is mainly attributed to the moderate adsorption energy of copper catalysts for *CO and their favorable effects on the hydrogenation of *CO intermediates and C–C coupling reactions (ChemPhysChem, 2017, 18, 3266-3273). For example, Chinese Patent Publication No. CN115490258A discloses a copper oxide nanosheet catalyst, the copper oxide nanosheets obtained by this preparation method being favorable for the electrocatalytic conversion of CO2 / CO C–C coupling reactions. 2+The Faraday efficiency of the product can reach 85% or higher. Achieving low hydrogen evolution Faraday efficiency and high electroreduction CO conversion capacity at industrial ampere-level current densities often depends on the inherent properties of the catalyst. For example, a polycrystalline copper nanomaterial mentioned in Chinese Patent Publication No. CN113913932A, prepared by this method, yields polycrystalline copper nanoparticles with a current density of 0.9 A cm⁻¹. -2 It has about 70% C at current density 2+ Faraday efficiency. The copper-palladium alloy nanoparticle catalyst prepared by Chinese patent publication number CN113881955A can achieve Faraday efficiency at 425 mA / cm². -2 It achieved an acetic acid faradaic efficiency of 70% at partial current density, but did not meet the testing conditions for industrial ampere levels.

[0005] Although copper-based catalysts have significant advantages in C production during the electroreduction of CO, 2+ Performance, but whether it can operate at industrial ampere-level current densities and maintain its resistance to C 2+ Excellent product selectivity remains a key area for further development. Therefore, developing a copper-based catalyst that is simple and rapid to synthesize, can operate at ampere-level current densities, and exhibits excellent performance is of great significance for industrial scalability. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a copper-based catalyst that can achieve industrial ampere-level current density, as well as its products and applications. The preparation method is simple and efficient, and the prepared copper-based catalyst has a high activity of electroreducing CO at industrial ampere-level current density.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a copper-based catalyst capable of achieving industrial-grade ampere-level current density, the method comprising the following steps:

[0009] (1) Dissolve the copper salt and alkaline substance to form a mixed solution;

[0010] (2) The mixed solution obtained in step (1) is subjected to hydrothermal treatment to obtain a copper precursor;

[0011] (3) The copper precursor prepared in step (2) is calcined to obtain a copper-based catalyst.

[0012] This invention utilizes alkaline substances as precipitants to form metal compounds through simple hydrothermal treatment, and then converts the copper compounds into copper-based catalysts with excellent performance through calcination.

[0013] The copper salts described in this invention include one or more of inorganic copper salts such as copper nitrate, copper sulfate, copper acetate, and copper chloride, or a mixture thereof.

[0014] Preferably, the copper salt is copper nitrate and copper chloride. More preferably, it is copper nitrate.

[0015] The alkaline substance described in this invention can be one or more of alkaline substances such as ammonia, urea, ammonium fluoride, ammonium hydrogen fluoride, sodium hydroxide, and potassium hydroxide.

[0016] Preferably, the alkaline substance is urea and ammonium fluoride. More preferably, it is urea.

[0017] The molar ratio of the copper salt to the alkaline substance described in this invention is 1.0:1.0 to 15.0.

[0018] Preferably, the molar ratio of copper salt to alkaline substance is 1.0:2.0 to 6.0. More preferably, the molar ratio of copper salt to alkaline substance is 1.0:2.0 to 5.0.

[0019] The hydrothermal treatment temperature described in this invention is 80–200°C.

[0020] Preferably, the hydrothermal temperature is 100–180°C, and more preferably 120–140°C.

[0021] The hydrothermal treatment time described in this invention is 8 to 24 hours.

[0022] Preferably, the hydrothermal treatment time is 10 to 16 hours, and more preferably 12 to 14 hours.

[0023] The copper precursor described in this invention is calcined at a temperature of 300–600°C.

[0024] Preferably, the calcination temperature is 400–500°C, and more preferably 450°C.

[0025] The copper precursor described in this invention is calcined for 4 to 12 hours.

[0026] Preferably, the calcination time is 5 to 8 hours, and more preferably 6 hours.

[0027] The present invention also provides a copper-based catalyst obtained according to the above preparation method.

[0028] The copper-based catalyst exhibits a blocky structure and has a sponge-like nanoporous structure on its surface.

[0029] This invention also discloses the application of the above-mentioned copper-based catalyst in the electroreduction of CO reaction. The application is the electroreduction of CO reaction at industrial ampere-level current densities.

[0030] This catalyst can be directly used for the electroreduction of CO to produce C. 2+ The product requires no further processing. This catalyst exhibits excellent electrocatalytic performance in application, ranging from 0.1 to 1.1 A cm⁻¹. -2 Within the current density range, the Faraday efficiency of H2 is less than 2%, and C 2+ The product has a Faraday efficiency greater than 97%. (0.1–2.0 A cm⁻¹) -2 Within the current density range, C 2+ The Faraday efficiency of the products is maintained at over 90%, meeting the current density requirements for industrial ampere-level applications.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] In this invention, copper-based materials capable of achieving industrial-grade ampere-level operating current densities can be prepared using simple hydrothermal and calcination processes. The preparation process is simple, highly controllable, uses widely available raw materials, is low-cost, environmentally friendly, and can be mass-produced, making it suitable for industrial production. The copper-based catalyst provided by this invention exhibits excellent electrocatalytic reduction activity and stability for CO, and it still demonstrates excellent electrocatalytic performance in the electroreduction of CO at ampere-level current densities. Attached Figure Description

[0033] Figure 1 This is a scanning electron microscope (SEM) image of the copper-based catalyst prepared in Example 1.

[0034] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the copper-based catalyst prepared in Example 1.

[0035] Figure 3 This is a scanning electron microscope (SEM) image of the copper-based catalyst prepared in Example 2.

[0036] Figure 4 The image shows the X-ray diffraction (XRD) pattern of the copper-based catalyst prepared in Example 2.

[0037] Figure 5 The graph shows the electroreduction CO reaction performance of the copper-based catalyst prepared in Example 1.

[0038] Figure 6 This is a stability diagram of the large-area electroreduction CO reaction of the copper-based catalyst prepared in Example 1.

[0039] Figure 7 The graph shows the electroreduction CO reaction performance of the copper-based catalyst prepared in Example 2. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0041] All raw materials used in the following specific implementation methods were purchased from the market.

[0042] Example 1

[0043] (1) Dissolve copper nitrate and urea in 50 mL of deionized water at a molar ratio of 1.0:2.0 and stir until homogeneous;

[0044] (2) The mixed solution obtained in step (1) was transferred to a hydrothermal reactor and hydrothermally reacted at 140°C for 6 hours. After the hydrothermal reactor cooled, the precipitate was centrifuged and dried to obtain the copper precursor.

[0045] (3) The copper precursor prepared in step (2) was calcined in a muffle furnace at 450°C for 6 hours to obtain a copper-based catalyst that can achieve industrial ampere-level current density.

[0046] Figure 1 Here is a scanning electron microscope (SEM) image of the copper-based catalyst synthesized in Example 1. Figure 1 As can be seen, the catalyst body exhibits a blocky structure, and its surface also has a sponge-like nanoporous structure.

[0047] Figure 2 The X-ray diffraction (XRD) pattern of the copper-based catalyst synthesized in Example 1 is shown below. Figure 2 As can be seen from the data, the characteristic peaks of the catalyst belong to the XRD diffraction peaks of copper oxide.

[0048] Example 2

[0049] (1) Dissolve copper sulfate and ammonium fluoride in 50 mL of deionized water at a molar ratio of 1.0:5.0 and stir until homogeneous;

[0050] (2) The mixed solution obtained in step (1) was transferred to a hydrothermal reactor and hydrothermally reacted at 120°C for 12 hours. After the hydrothermal reactor cooled, the precipitate was centrifuged and dried to obtain the copper precursor.

[0051] (3) The copper precursor prepared in step (2) was calcined in a muffle furnace at 450°C for 6 hours to obtain a copper-based catalyst that can achieve industrial ampere-level current density.

[0052] Figure 3 Here is a scanning electron microscope (SEM) image of the copper-based catalyst synthesized in Example 2. Figure 3 As can be seen, the catalyst body exhibits a blocky structure, and its surface also has a sponge-like nanoporous structure.

[0053] Figure 4 The X-ray diffraction (XRD) pattern of the copper-based catalyst synthesized in Example 2 is shown below. Figure 4 As can be seen from the data, the characteristic peaks of the catalyst belong to the XRD diffraction peaks of copper oxide.

[0054] Example 3

[0055] (1) Dissolve copper nitrate and ammonia in 50 mL of deionized water at a molar ratio of 1.0:3.0 and stir until homogeneous;

[0056] (2) The mixed solution obtained in step (1) was transferred to a hydrothermal reactor and hydrothermally reacted at 130°C for 12 hours. After the hydrothermal reactor cooled, the precipitate was centrifuged and dried to obtain the copper precursor.

[0057] (3) The copper precursor prepared in step (2) was calcined in a muffle furnace at 450°C for 6 hours to obtain a copper-based catalyst that can achieve industrial ampere-level current density.

[0058] Application Example 1

[0059] Example 1: Preparation of C by Electroreduction of CO 2+ Cathode material of the product:

[0060] (1) Weigh 20 mg of the copper-based catalyst prepared in Example 1 using an analytical balance, then add 900 μL of anhydrous ethanol and 100 μL of 0.5 wt.% Nafion solution, and sonicate for 2 h to make it a uniformly dispersed catalyst slurry.

[0061] (2) The uniformly mixed catalyst slurry is sprayed evenly onto YLS-30T conductive carbon paper using a spray gun. The carbon paper is heated and dried during the spraying process.

[0062] (3) Electrochemical performance was tested in a flow electrolytic cell using Ag / AgCl as the reference electrode and nickel foam as the reaction counter electrode. The copper-based catalyst prepared in Example 1 was used as the working electrode, with an effective electrode area of ​​1.0 × 1.0 cm². 2 Using 1.0 mol / L potassium hydroxide as the electrolyte, a continuous flow of CO gas was maintained, and the electroreduction performance of CO was tested at different current densities. The gaseous products were analyzed by gas chromatography, and the liquid products were analyzed by... 1 H nuclear magnetic resonance spectroscopy analysis (600MHz).

[0063] Figure 5The graph shows the electroreduction CO reaction performance of the copper-based catalyst prepared in Example 1. The electroreduction reaction is performed in the range of 0.1–1.1 A / cm². -2 Within the current density range, the Faraday efficiency of H2 is less than 2%, and C 2+ The product has a Faraday efficiency greater than 97%. (0.1–2.0 A cm⁻¹) -2 Within the current density range, C 2+ The Faraday efficiency of the products is maintained at over 90%, meeting the current density requirements for industrial ampere-level applications.

[0064] The copper-based catalyst prepared in this invention was subjected to device-scale current testing using a two-electrode membrane electrode system (effective electrode area 100 cm²). 2 The reaction was carried out using a titanium mesh loaded with iridium trioxide as the anode. The current and potential of the reaction system were controlled by a DC power supply. At a total current of 20 A, the copper-based catalyst synthesized in this invention showed good stability after 120 minutes of testing. Figure 6 ), able to maintain a high C 2+ It exhibits excellent product selectivity and electrochemical stability, and has broad application prospects.

[0065] Application Example 2

[0066] Example 2: Preparation of C by Electroreduction of CO 2+ Cathode material of the product:

[0067] (1) Weigh 20 mg of the copper-based catalyst prepared in Example 2 using an analytical balance, then add 900 μL of anhydrous ethanol and 100 μL of 0.5 wt.% Nafion solution, and sonicate for 2 h to make it a uniformly dispersed catalyst slurry.

[0068] (2) The uniformly mixed catalyst slurry is sprayed evenly onto YLS-30T conductive carbon paper using a spray gun. The carbon paper is heated and dried during the spraying process.

[0069] (3) Electrochemical performance was tested in a flow electrolytic cell using Ag / AgCl as the reference electrode and nickel foam as the reaction counter electrode. The copper-based catalyst prepared in Example 2 was used as the working electrode, with an effective electrode area of ​​1.0 × 1.0 cm². 2 Using 1.0 mol / L potassium hydroxide as the electrolyte, a continuous flow of CO gas was maintained, and the electroreduction performance of CO was tested at different current densities. The gaseous products were analyzed by gas chromatography, and the liquid products were analyzed by... 1 H nuclear magnetic resonance spectroscopy analysis (600MHz).

[0070] Figure 7 The graph shows the electroreduction CO reaction performance of the copper-based catalyst prepared in Example 2. The electroreduction reaction is performed in the range of 0.3–2.0 A / cm².-2 Within the current density range, C 2+ The Faraday efficiency of the products is maintained at over 90%, meeting the current density requirements for industrial ampere-level applications.

Claims

1. The application of a copper-based catalyst in the electroreduction of CO, characterized in that, The application is the electroreduction of CO to produce multi-carbon products under industrial ampere-level current density. The preparation method of the copper-based catalyst includes the following steps: (1) Dissolve the copper salt and alkaline substance to form a mixed solution, wherein the molar ratio of copper salt to alkaline substance is 1.0 : 2.0~5.0; (2) The mixed solution obtained in step (1) is subjected to hydrothermal treatment to obtain a copper precursor; (3) The copper precursor prepared in step (2) is calcined to obtain a copper-based catalyst; The copper precursor in step (3) is calcined at a temperature of 450 °C for 6 h.

2. The application according to claim 1, characterized in that, The copper salt mentioned in step (1) is an inorganic copper salt, selected from one or more of copper nitrate, copper sulfate, copper acetate or copper chloride.

3. The application according to claim 1, characterized in that, The alkaline substance in step (1) is selected from one or more of urea, ammonia, ammonium fluoride, potassium hydroxide, or sodium hydroxide, or a mixture thereof.

4. The application according to claim 1, characterized in that, The copper-based catalyst exhibits a blocky structure and has a sponge-like nanoporous structure on its surface.

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