Ni-n-c supported copper nanosheet catalyst and preparation method and application thereof

Abstract

The application discloses a kind of Ni-N-C supported copper nanosheet catalyst and its preparation method and application, belong to electrocatalytic material and energy conversion technical field.The Ni-N-C supported copper nanosheet catalyst provided in the application uses Ni-N-C single atom / nanocluster and porous copper nanosheet close composite and "surface migration" series catalysis combination technical scheme, in the preparation process of CO2 electroreduction catalyst, the Ni NPS&SA ‑NC‑L x As CO generating unit, form atomic level adjacent interface with porous copper nanosheet, realize the directional surface migration of ·CO intermediate, regulate the active site distribution and mass transfer efficiency of catalyst.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials and energy conversion technology, specifically relating to a Ni-NC supported copper nanosheet catalyst, its preparation method, and its application. Background Technology

[0002] With the deepening of the Industrial Revolution, the massive consumption of fossil fuels has led to a sharp increase in atmospheric carbon dioxide (CO2) concentration, triggering severe environmental problems such as global warming. Achieving CO2 capture and conversion has become a key pathway for building a sustainable energy system and realizing the carbon cycle. Electrocatalytic carbon dioxide reduction (CO2RR) has become one of the most promising technologies for CO2 conversion due to its mild reaction conditions and the ability to be directly driven by electricity generated from renewable energy sources (solar, wind, etc.).

[0003] Among the many reduction products of CO2RR, ethylene (C2H4), as an important basic chemical raw material, is widely used in plastics, rubber, and fiber industries, and has extremely high economic value. Therefore, achieving highly selective and efficient electroreduction of CO2 to C2H4 has become the current research frontier and focus. Currently, copper (Cu) is the only metal that can catalyze the production of large amounts of hydrocarbons and alcohols from CO2. However, as a single catalyst, it has inherent defects such as wide product distribution and low selectivity. The core bottleneck lies in the slow kinetics of CO2 to CO intermediate conversion, resulting in insufficient CO intermediate coverage on the Cu surface, which limits the efficiency of subsequent CC coupling reactions.

[0004] To address the aforementioned issues, the "tandem catalysis" strategy has been extensively studied. This strategy decomposes CO2RR into two steps: efficient generation of the ·CO intermediate at one site, followed by further reduction of CO and CC coupling at the other site. However, traditional tandem catalytic systems (such as Au / Cu physical mixtures) rely on the "desorption-solution diffusion-re-adsorption" process of the ·CO intermediate, which suffers from slow mass transfer rates and significant energy losses, making it difficult to improve catalytic efficiency.

[0005] Atomic-scale dispersed Ni-NC single-atom / nanocluster composite catalysts exhibit excellent CO2-to-CO catalytic performance and can accelerate the formation of ·CO and ·OH intermediates through a hydrogen spillover mechanism. However, how to tightly couple them with Cu-based catalysts to construct an efficient tandem system and overcome mass transfer limitations remains a pressing technical challenge. Furthermore, the morphology and crystal facet control of existing Cu-based catalysts are difficult to achieve simultaneously high activity, high selectivity, and high stability, and their performance in practical devices such as Zn-CO2 batteries requires further optimization. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a Ni-NC supported copper nanosheet catalyst, its preparation method, and its applications. Through an innovative tandem catalytic mechanism and structural design, it overcomes the mass transfer bottlenecks and performance defects of traditional catalysts, achieving highly efficient and selective conversion of CO2 to C2H4, while also expanding its applications in energy storage and conversion devices.

[0007] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention is to provide a method for preparing a Ni-NC supported copper nanosheet catalyst, comprising the following steps: Soluble zinc salt, soluble nickel salt, and organic ligands were mixed in water, then mixed with a solution containing polydopamine. The mixture was then subjected to light-protected aging, drying, and pyrolysis to obtain a Ni particle-Ni single-atom synergistic catalyst (Ni...). NPS&SA -NC-L x The Ni particles and Ni single-atom synergistic catalyst are combined with Cu-containing... 2+ The solutions were mixed and then added to a sodium hydroxide solution. After hydrothermal reaction, the resulting precipitate was electrochemically reduced in a CO2-saturated potassium bicarbonate solution to obtain the Ni-NC supported copper nanosheet catalyst.

[0008] This invention yields a Ni-NC supported copper nanosheet catalyst, utilizing a Ni single-atom / nanocluster composite structure (Ni NPS&SA -NC-L x Using a carrier, porous copper nanosheets (pCu NS) are tightly loaded on the surface of the carrier to form an atomic-scale proximity interface, constituting a tandem catalytic system based on a "surface migration" mechanism.

[0009] Ni NPS&SA -NC-L x As a CO generation unit, it has excellent CO2-to-CO catalytic activity and can efficiently generate CO intermediates over a wide potential range. The porous copper nanosheets, as CC coupling units, have a two-dimensional nanosheet morphology with submicron to nanoscale pores and high-density nano defects on the surface, mainly exposing Cu(100) crystal planes, with copper element mainly in the zero-valent metallic state.

[0010] Ni-NC single-atom / nanocluster composite structures, as materials with excellent CO2 activation performance, exhibit unique value in tandem catalytic systems due to their unique synergistic structure of single atoms and nanoclusters and their highly efficient CO generation capability. Their high selectivity for CO2 activation makes them not only efficient units for generating ·CO intermediates but also important tools for regulating the microenvironment of Cu-based active sites. NPS&SA -NC-L xIt can catalyze the conversion of CO2 to CO with near-specificity over a wide potential range, and the Ni nanoclusters on its surface can efficiently dissociate water through a hydrogen overflow mechanism to generate adsorbed hydrogen, accelerating the formation of the ·COOH intermediate and providing favorable conditions for the formation of the ·CO intermediate. NPS&SA -NC-L x It possesses excellent chemical stability and electronic conductivity, and is not prone to structural collapse or loss of active components during electrocatalytic reactions. Its tight composite structure with porous copper nanosheets enables not only the efficient generation of ·CO intermediates but also directional surface migration of these intermediates, avoiding mass transfer losses caused by solution diffusion. This property allows Ni... NPS&SA -NC-L x It plays a crucial role in balancing catalyst activity, selectivity, and mass transfer efficiency, providing an important approach for the precise optimization of catalytic performance in tandem catalytic systems.

[0011] This invention uses high-performance Ni NPS&SA -NC-L x As a unit for ·CO intermediate generation, it utilizes its highly efficient CO2-to-CO catalytic activity and hydrogen spillover effect, combined with the high specific surface area, abundant defects, and Cu(100) crystal plane advantages of porous copper nanosheets, to construct a tightly coupled tandem catalytic system, achieving surface migration of ·CO intermediates and improving the performance of CO2 electroreduction to C2H4 conversion. On the one hand, Ni NPS&SA -NC-L x It possesses excellent chemical stability and electronic conductivity, which does not affect the activity and stability of porous copper nanosheets. Simultaneously, its efficient CO generation capacity provides ample ·CO intermediates for Cu active sites, promoting the CC coupling reaction. Furthermore, the high specific surface area and abundant defects of porous copper nanosheets increase the electrochemical active area, while the Cu(100) crystal plane optimizes the adsorption strength of ·CO intermediates and suppresses hydrogen evolution side reactions. The synergistic effect of these two factors achieves a comprehensive improvement in catalytic performance.

[0012] Preferably, the soluble zinc salt is zinc nitrate; the soluble nickel salt is nickel nitrate; the organic ligand is 2-methylimidazole; the molar ratio of Zn in the soluble zinc salt to the organic ligand is 1:16.15; and the molar ratio of Zn in the soluble zinc salt to Ni in the soluble nickel salt is 6.4:1.

[0013] Preferably, the solvent in the polydopamine-containing solution is an equal volume mixture of anhydrous ethanol and water.

[0014] Preferably, the polydopamine-containing solution also contains ammonia.

[0015] Preferably, the temperature for light-protected aging is 30~50℃, and the time is 20~28h.

[0016] Preferably, the drying is vacuum drying.

[0017] Preferably, the pyrolysis is carried out under an inert atmosphere, with a pyrolysis temperature of 850~950℃, a holding time of 1~3h, and a heating rate of 5~6℃ / min.

[0018] Preferably, the Ni particles and Ni single-atom synergistic catalyst and Cu-containing 2+ Cu in solution 2+ The dosage ratio is 25~75mg:2.5mmol.

[0019] Preferably, the Cu-containing 2+ Cu in solution 2+ The concentration of the sodium hydroxide solution is 50 mM; the concentration of the sodium hydroxide solution is 3 M.

[0020] More preferably, the Cu-containing 2+ The volume ratio of the solution to the sodium hydroxide solution is 5:2.

[0021] Preferably, the hydrothermal reaction is carried out at a temperature of 75-85°C for 12-15 hours.

[0022] Preferably, the concentration of potassium bicarbonate in the CO2-saturated potassium bicarbonate solution is 0.1M.

[0023] Preferably, the voltage for the electrochemical topological reduction is -0.9V and the time is 1h.

[0024] The second technical solution of the present invention provides a Ni-NC supported copper nanosheet catalyst prepared according to the above-mentioned method for preparing Ni-NC supported copper nanosheet catalyst.

[0025] The third technical solution of the present invention provides an application of the above-mentioned Ni-NC supported copper nanosheet catalyst in the electrocatalytic reduction of carbon dioxide to ethylene catalyst.

[0026] The beneficial technical effects of the present invention are as follows: The Ni-NC supported copper nanosheet catalyst provided by this invention employs a technical solution combining the tight composite of Ni-NC single atoms / nanoclusters and porous copper nanosheets with "surface migration" tandem catalysis. During the preparation of the CO2 electroreduction catalyst, Ni is introduced... NPS&SA -NC-L x As a CO-generating unit, it forms an atomically close interface with porous copper nanosheets, enabling directional surface migration of ·CO intermediates and modulating the distribution of active sites and mass transfer efficiency of the catalyst. The Ni used... NPS&SA -NC-L xIt does not introduce additional residual substances during catalyst preparation and can also act as an electron transport medium dispersed inside the catalyst, helping to improve the conductivity of the catalyst, enabling the preparation of highly selective and highly stable CO2 electroreduction catalysts, and improving catalytic performance and practical application value. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The flowchart for the preparation of Ni-NC supported copper nanosheet catalysts in Examples (a) and Examples 1-3 show the XNi catalysts prepared in Examples 1-3. NPS&SA -NC-L 0.5 XRD patterns of CuO NS (X=25, 50, 75) (b), and 50Ni prepared in Example 1. NPS&SA -NC-L 0.5 XRD pattern of / pCu NS (c).

[0029] Figure 2 50Ni in Example 1 NPS&SA -NC-L 0.5 / CuO NS (a) and 50Ni NPS&SA -NC-L 0.5 SEM image of / pCu NS(b).

[0030] Figure 3 The images show the TEM images (a) and HADDF-TEM images (b) of pCu NS in Comparative Example 1.

[0031] Figure 4 LSV curves (a), carbon monoxide current density plots (b), catalyst stability test plots (c), and Tafel slope plots (d) of the catalysts prepared for Examples 1-3 and Comparative Example 1 under saturated CO2.

[0032] Figure 5 pCu NS(a) prepared for Comparative Example 1 and 25Ni prepared for Example 2 NPS&SA -NC-L 0.5 / pCu NS(b), 50Ni prepared in Example 1 NPS&SA -NC-L 0.5 / pCu NS(c) and 75Ni prepared in Example 3 NPS&SA -NC-L 0.5The overall Faraday efficiency plot of / pCu NS(d).

[0033] Figure 6 Electrochemical double-layer capacitance (ESCA) plots (a) for each catalyst prepared in Examples 1-3 and Comparative Example 1, and ethylene current density plots (b) under different atmospheres of carbon dioxide and carbon monoxide. Detailed Implementation

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0035] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0036] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0038] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0039] Unless otherwise specified, room temperature in this invention refers to a temperature of 20±10℃.

[0040] The weight-average molecular weight of the PDA used in this embodiment of the invention is 189.64.

[0041] The preparation steps of the PDA solution used in this embodiment of the invention are as follows: 0.5 g of polydopamine (PDA) is dissolved in a mixed solution of 20 mL of distilled water and 20 mL of anhydrous ethanol, 300 μL of ammonia water with a mass fraction of 25% is added, and the solution is sonicated for 10 min until it turns a uniform rose-red color.

[0042] Example 1 A Ni-NC supported copper nanosheet catalyst (50NiNPS&SA -NC-L 0.5 The preparation method of / pCu NS) is as follows: Step 1: Solution A was prepared by dissolving zinc nitrate hexahydrate (Zn(NO3)2•6H2O, 0.59 g) and nickel nitrate hexahydrate (Ni(NO3)2•6H2O, 90.08 mg) in 100 mL of distilled water. Separately, solution B was prepared by dissolving 2-methylimidazole (2.63 g) in 100 mL of deionized water. Solution A was rapidly injected into solution B, and PDA solution was added simultaneously. The mixture was stirred continuously (600 rpm) and aged at 40°C in the dark for 24 h, followed by drying at 60°C. The dried sample precursor was then pyrolyzed in a tube furnace under a N2 atmosphere at a heating rate of 5 °C / min to 900°C, held at that temperature for 2 h, and allowed to cool naturally to room temperature to obtain a black powder of Ni. NPS&SA -NC-L 0.5 .

[0043] Step 2: Weigh 2.131g CuCl2·2H2O, dissolve it in 100mL of deionized water, place it on a magnetic stirrer, and stir vigorously at 500 rpm for 30 min to ensure that CuCl2·2H2O is completely dissolved, forming a homogeneous CuCl2 solution with a concentration of 50 mM. 2+ Solution; take 50 mL Cu 2+ The solution was supplemented with 50 mg of Ni prepared in step 1. NPS&SA -NC-L 0.5 Under continuous vigorous stirring (500 rpm), the solution was slowly added dropwise to 20 mL of 3M NaOH solution at a dropping rate of 1 mL / min, and stirred in a constant temperature water bath at 50 °C for 1 h. The mixture was then transferred to a high-pressure reactor, sealed tightly, and placed in an oven for hydrothermal reaction at 80 °C for 12 h, followed by natural cooling to room temperature. 50Ni was obtained by centrifugation, washing, and drying at 60 °C for 12 h. NPS&SA -NC-L 0.5 / CuO NS.

[0044] Step 3: The 50Ni prepared in Step 2... NPS&SA -NC-L 0.5 / CuO NS was dispersed in a CO2-saturated 0.1 M KHCO3 electrolyte solution, and topological reduction was performed at a constant voltage of -0.9 V for 1 h using Ag / AgCl as the reference electrode to finally obtain 50Ni NPS&SA -NC-L 0.5 / pCu NS catalyst.

[0045] Example 2 A Ni-NC supported copper nanosheet catalyst (25Ni NPS&SA -NC-L 0.5 The preparation method of / pCu NS) is as follows: Step 1: Solution A was prepared by dissolving zinc nitrate hexahydrate (Zn(NO3)2•6H2O, 0.59 g) and nickel nitrate hexahydrate (Ni(NO3)2•6H2O, 90.08 mg) in 100 mL of distilled water. Separately, solution B was prepared by dissolving 2-methylimidazole (2.63 g) in 100 mL of deionized water. Solution A was rapidly injected into solution B, and PDA solution was added simultaneously. The mixture was stirred continuously (600 rpm) and aged at 40°C in the dark for 24 h, followed by drying at 60°C. The dried sample precursor was then pyrolyzed in a tube furnace under a N2 atmosphere at a heating rate of 5°C / min to 900°C, held at that temperature for 2 h, and allowed to cool naturally to room temperature to obtain a black powder of Ni. NPS&SA -NC-L 0.5 .

[0046] Step 2: Weigh 2.131g CuCl2·2H2O, dissolve it in 100mL of deionized water, place it on a magnetic stirrer, and stir vigorously at 500 rpm for 30 min to ensure that CuCl2·2H2O is completely dissolved, forming a homogeneous CuCl2 solution with a concentration of 50 mM. 2+ Solution; take 50 mL Cu 2+ The solution was supplemented with 25 mg of Ni prepared in step 1. NPS&SA -NC-L 0.5 Under continuous vigorous stirring (500 rpm), the solution was slowly added dropwise to 20 mL of 3M NaOH solution at a dropping rate of 1 mL / min, and stirred in a constant temperature water bath at 50 °C for 1 h. The mixture was then transferred to a high-pressure reactor, sealed tightly, and placed in an oven for hydrothermal reaction at 80 °C for 12 h, followed by natural cooling to room temperature. 25Ni was obtained by centrifugation, washing, and drying at 60 °C for 12 h. NPS&SA -NC-L 0.5 / CuO NS.

[0047] Step 3: The 25Ni prepared in Step 2... NPS&SA -NC-L 0.5 / CuO NS was dispersed in a CO2-saturated 0.2 M KHCO3 electrolyte solution, and topological reduction was performed for 1.5 h at a constant voltage of -0.9 V using Ag / AgCl as the reference electrode to finally obtain 25Ni NPS&SA -NC-L 0.5 / pCu NS catalyst.

[0048] Example 3 A Ni-NC supported copper nanosheet catalyst (75Ni NPS&SA -NC-L 0.5 The preparation method of / pCu NS) is as follows: Step 1: Solution A was prepared by dissolving zinc nitrate hexahydrate (Zn(NO3)2•6H2O, 0.59 g) and nickel nitrate hexahydrate (Ni(NO3)2•6H2O, 90.08 mg) in 100 mL of distilled water. Separately, solution B was prepared by dissolving 2-methylimidazole (2.63 g) in 100 mL of deionized water. Solution A was rapidly injected into solution B, and PDA solution was added simultaneously. The mixture was stirred continuously (600 rpm) and aged at 40°C in the dark for 24 h, followed by drying at 60°C. The dried sample precursor was then pyrolyzed in a tube furnace under a N2 atmosphere at a heating rate of 5°C / min to 900°C, held at that temperature for 2 h, and allowed to cool naturally to room temperature to obtain a black powder of Ni. NPS&SA -NC-L 0.5 .

[0049] Step 2: Weigh 2.131g CuCl2·2H2O, dissolve it in 100mL of deionized water, place it on a magnetic stirrer, and stir vigorously at 500 rpm for 30 min to ensure that CuCl2·2H2O is completely dissolved, forming a homogeneous CuCl2 solution with a concentration of 50 mM. 2+ Solution; take 50 mL of the above Cu 2+ The solution was supplemented with 75 mg of Ni prepared in step 1. NPS&SA -NC-L 0.5 Under continuous vigorous stirring (500 rpm), the solution was slowly added dropwise to 20 mL of 3M NaOH solution at a dropping rate of 1 mL / min, and stirred in a constant temperature water bath at 50 °C for 1 h. The mixture was then transferred to a high-pressure reactor, sealed tightly, and placed in an oven for hydrothermal reaction at 80 °C for 12 h, followed by natural cooling to room temperature. 75Ni was obtained by centrifugation, washing, and drying at 60 °C for 12 h. NPS&SA -NC-L 0.5 / CuO NS.

[0050] Step 3: The 75Ni prepared in Step 2... NPS&SA -NC-L 0.5 / CuO NS was dispersed in a CO2-saturated 0.15 M KHCO3 electrolyte solution, and topological reduction was performed at a constant voltage of -0.9 V for 2 h using Ag / AgCl as the reference electrode to finally obtain 75Ni. NPS&SA -NC-L 0.5 / pCu NS catalyst.

[0051] Comparative Example 1 A method for preparing porous copper nanosheets (pCu NS) by electrochemical topological reduction, comprising the following steps: Step 1: Hydrothermal synthesis of CuO nanosheets (CuO Ns): Weigh 2.131 g CuCl2·2H2O, dissolve it in 100 mL of deionized water, place it on a magnetic stirrer, and stir vigorously at 500 rpm for 30 min to ensure that CuCl2·2H2O is completely dissolved, forming a homogeneous CuO nanosheet with a concentration of 50 mM. 2+ Solution; take 50 mL Cu 2+ The solution was slowly added dropwise to 20 mL of 3M NaOH solution at a dropping rate of 1 mL / min under continuous vigorous stirring (500 rpm). The mixture was stirred in a constant temperature water bath at 50 °C for 1 h. The mixture was then transferred to a high-pressure reactor, sealed tightly, and placed in an oven for hydrothermal reaction at 80 °C for 12 h. After natural cooling to room temperature, CuO nanosheets (CuONs) were obtained by centrifugation, washing, and drying at 60 °C for 12 h.

[0052] Step 2: Electrochemical topological reduction to prepare porous copper nanosheets (pCu NS). The CuO nanosheets prepared in Step 2 were dispersed in a CO2-saturated 0.2 M KHCO3 electrolyte solution. Using Ag / AgCl as the reference electrode, topological reduction was performed at a constant voltage of -0.9 V for 1.5 h to obtain porous copper nanosheets (pCu NS).

[0053] The catalyst samples prepared in Examples 1-3 and Comparative Example 1 were subjected to a series of characterization and performance tests. The test results are as follows: 1. Catalyst Synthesis and Structural Characterization: Flowchart (a) for the preparation of Ni-NC supported copper nanosheet catalysts in Examples 1-3, and XNi catalysts prepared in Examples 1-3. NPS&SA -NC-L 0.5 XRD patterns of CuO NS (X=25, 50, 75) (b), and 50Ni prepared in Example 1. NPS&SA -NC-L 0.5 The XRD pattern of / pCu NS (c) is shown in [reference needed]. Figure 1 .

[0054] 50Ni in Example 1 NPS&SA -NC-L 0.5 / CuO NS (a) and 50Ni NPS&SA -NC-L 0.5 The SEM image of / pCu NS(b) is shown below. Figure 2 .

[0055] The TEM image (a) and HADDF-TEM image (b) of pCu NS in Comparative Example 1 are shown below. Figure 3 .

[0056] Figure 1 (a) shows the Ni prepared in the example. NPS&SA -NC-L 0.5 Synthesis process of / pCu NS catalyst. Figure 1 Figure (b) shows the Ni prepared in each example before electroreduction. NPS&SA -NC-L 0.5 X-ray diffraction (XRD) pattern of CuO NS, showing XNi NPS&SA -NC-L 0.5 The XRD pattern of CuO NS matches well with CuO (PDF #48-1548). Figure 1 (c) shows the 50Ni prepared in Example 1 after electroreduction. NPS&SA -NC-L 0.5 The XRD pattern of / pCu NS showed that CuO was successfully converted into metallic Cu. Scanning electron microscopy (SEM) was used to systematically characterize the surface morphology and structural features of the prepared copper-based nanosheet catalyst. Figure 2 The results show that after the electrochemical reduction process, pCu NS retains the same original nanosheet structure as CuO NS. pCu NS exhibits a typical two-dimensional nanosheet morphology with a significantly roughened surface and abundant submicron to nanoscale pores. This porous structure is beneficial for increasing the electrochemical active area and promoting reactant transport. The TEM image of pCu NS in Comparative Example 1 clearly shows its typical two-dimensional nanosheet morphology. Figure 3 In (a), the HAADF-STEM image further confirms that these pores penetrate the surface of the nanosheet, forming interconnected nanopores. Figure 3 (b)

[0057] 2. Evaluation of the catalyst's CO2 electroreduction performance: For the H-type battery, the catalyst ink consisted of 5 mg of catalyst powder, 20 μL of Nafion solution (5 wt%), and 230 μL of isopropanol (as a solution), and was ultrasonically dispersed for at least 1 h to ensure uniform mixing. Subsequently, 50 μL of the catalyst ink was dropped onto carbon paper (SGL SIGRACET 28BC) to achieve a 1 mg·cm⁻¹ concentration. -2 The catalyst loading was determined. Electrochemical measurements of the H-type battery were performed using a three-electrode system. The anode and cathode chambers were separated by a pre-activated proton exchange membrane (Nafion 117), and the electrolyte was a 0.5 M KHCO3 solution. A platinum plate (1 × 1 cm²) was used. 2The Ag / AgCl electrode and the counter electrode were used as the reference electrode, respectively. Before electrolysis, the solution was prepared at 50 mL / min. -1 The electrolyte was purified and saturated using high-purity CO2 gas. A flow rate of 20 mV·s was adopted. -1 The scan rate was measured using linear sweep voltammetry (LSV). The CO2 reduction reaction (CO2RR) performance of the catalyst at different potentials was evaluated using galvanostatic method (CA).

[0058] 3. Catalyst stability test: After loading the catalyst onto carbon paper, chronoamperometry (CA) was used for continuous electrolysis at a constant potential of -0.8 V vs. RHE. During electrolysis, the retention of activity was assessed by monitoring changes in current density, and the Faradaic efficiency (FE) of CO was calculated by periodically detecting gaseous products using online gas chromatography (GC). CO )stability.

[0059] The LSV curves (a), carbon monoxide current density plots (b), catalyst stability test plots (c), and Tafel slope plots (d) of the catalysts prepared in Examples 1-3 and Comparative Example 1 under saturated CO2 are shown below. Figure 4 .

[0060] like Figure 4 As shown in (a), in a CO2-saturated 0.5 M KHCO3 electrolyte, 50Ni NPS&SA -NC-L 0.5 / pCu NS catalysts exhibit the combined advantages of lower overpotential and higher intrinsic activity in CO2RR.

[0061] like Figure 4 As shown in (b), Ni NPS&SA -NC-L 0.5 / pCu NS exhibits the highest CO current density (j CO This demonstrates its excellent intrinsic catalytic activity and charge transfer capability, as well as its extremely high CO generation rate and selectivity.

[0062] like Figure 4 As shown in (c), the durability of each catalyst was systematically evaluated by constant potential electrolysis (-0.8V vs. RHE, for 30 h) in CO2-saturated 0.5 M KHCO3 electrolyte. The results showed that 50Ni NPS&SA -NC-L 0.5 / pCu NS maintained an FE of over 50% throughout the entire test. C2H4 The current density remained almost constant, demonstrating excellent operational stability.

[0063] like Figure 4 As shown in (d), the Tafel slope is a key parameter for evaluating the kinetics of electrocatalytic reactions. A smaller value indicates a higher current density increase at the same overpotential increment, meaning a more rapid charge transfer kinetic. For 50Ni... NPS&SA -NC-L 0.5 / pCu NS, LSV tests clearly show that, at the same current density, the required overpotential is significantly lower than that of the control sample. This phenomenon strongly suggests that 50Ni NPS&SA -NC-L 0.5 / pCu NS exhibits a smaller Tafel slope, meaning that the CO2 reduction reaction on its surface has a faster charge transfer rate. This is attributed to its abundant porous structure and highly conductive metallic copper substrate, which provides excellent electron transport channels, while the numerous defect sites and Cu(100) crystal planes optimize the adsorption energy of reaction intermediates, collectively lowering the reaction energy barrier.

[0064] pCu NS(a) prepared in Comparative Example 1 and 25Ni prepared in Example 2 NPS&SA -NC-L 0.5 / pCu NS(b), 50Ni prepared in Example 1 NPS&SA -NC-L 0.5 / pCu NS(c) and 75Ni prepared in Example 3 NPS&SA -NC-L 0.5 The overall Faraday efficiency plot of / pCu NS(d) is shown in [the diagram]. Figure 5 .

[0065] like Figure 5 As shown, the 50Ni prepared in Example 1 NPS&SA -NC-L 0.5 / pCu NS catalysts can achieve higher FE values ​​than other catalysts at lower overpotentials and with a wider potential window. C2H4 The overall Faraday efficiency (FE) is close to 100%. 50Ni NPS&SA -NC-L 0.5 / pCu NS maximum FE C2H4 The value is 53.21% at -1.2 V vs. RHE.

[0066] The electrochemical double-layer capacitance (ESCA) graphs (a) of the catalysts prepared in Examples 1-3 and Comparative Example 1, and the ethylene current density graphs (b) under different atmospheres of carbon dioxide and carbon monoxide are shown in the figure. Figure 6 .

[0067] from Figure 6 As can be seen in (a), with Ni NPS&SA -NC-L 0.5As the loading increases, ECSA gradually increases, pCu NS, 25Ni NPS&SA -NC-L 0.5 / pCu NS, 50Ni NPS&SA -NC-L 0.5 / pCu NS, 75Ni NPS&SA -NC-L 0.5 The ECSA of / pCu NS was 11.8 mF cm⁻¹. -2 23.6 mF cm -2 42.6 mF cm -2 43.6 mF cm -2 This trend indicates a significant increase in the number of active sites on the catalyst surface available for electrochemical reactions. This phenomenon can be attributed to the geometric effects and interfacial structure evolution resulting from increased loading: with a fixed substrate geometry, higher loading means more pCu NS deposited on Ni. NPS&SA -NC-L 0.5 On the surface, a denser three-dimensional porous catalytic layer is formed. Figure 6 The experimental results in (b) show that, under a CO atmosphere, the pure Cu electrode exhibits high Faraday efficiency (FE) and partial current density j for C2H4. C2H4 with Ni NPS&SA -NC-L 0.5 The / pCu NS series electrodes showed highly similar performance under CO2 atmosphere. For example, at the same potential, their selectivity and activity towards ethylene were almost identical. This finding strongly confirms the Ni... NPS&SA -NC-L 0.5 As a highly efficient CO producer, it can establish a local microenvironment similar to pure CO reduction in situ on the Cu surface, thereby bypassing the kinetic limitations of CO2 activation on the pCu NS surface and directly promoting the occurrence of C–C coupling reaction.

[0068] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a Ni-NC supported copper nanosheet catalyst, characterized in that, Includes the following steps: A soluble zinc salt, a soluble nickel salt, and an organic ligand are mixed in water, then mixed with a solution containing polydopamine. The mixture is then subjected to light-protected aging, drying, and pyrolysis to obtain a Ni particle and Ni single-atom synergistic catalyst. This Ni particle and Ni single-atom synergistic catalyst is then mixed with a Cu-containing solution... 2+ The solutions were mixed and then added to a sodium hydroxide solution. After hydrothermal reaction, the resulting precipitate was electrochemically reduced in a CO2-saturated potassium bicarbonate solution to obtain the Ni-NC supported copper nanosheet catalyst.

2. The method for preparing the Ni-NC supported copper nanosheet catalyst according to claim 1, characterized in that, The soluble zinc salt is zinc nitrate; the soluble nickel salt is nickel nitrate; the organic ligand is 2-methylimidazolium; the molar ratio of Zn to the organic ligand in the soluble zinc salt is 1:16.15; the molar ratio of Zn in the soluble zinc salt to Ni in the soluble nickel salt is 6.4:

1.

3. The method for preparing the Ni-NC supported copper nanosheet catalyst according to claim 1, characterized in that, The light-protected aging process is carried out at a temperature of 30-50°C for 20-28 hours; and / or, the pyrolysis is carried out under an inert atmosphere at a temperature of 850-950°C, a holding time of 1-3 hours, and a heating rate of 5-6°C / min.

4. The method for preparing the Ni-NC supported copper nanosheet catalyst according to claim 1, characterized in that, The Ni particles and Ni single-atom synergistic catalyst and Cu-containing 2+ Cu in solution 2+ The dosage ratio is 25~75mg:2.5mmol.

5. The method for preparing the Ni-NC supported copper nanosheet catalyst according to claim 1, characterized in that, The Cu-containing 2 + Cu in solution 2+ The concentration of the sodium hydroxide solution is 50 mM; the concentration of the sodium hydroxide solution is 3 M.

6. The method for preparing the Ni-NC supported copper nanosheet catalyst according to claim 5, characterized in that, The Cu-containing 2 + The volume ratio of the solution to the sodium hydroxide solution is 5:

2.

7. The method for preparing the Ni-NC supported copper nanosheet catalyst according to claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 75-85℃ for 12-15 hours.

8. The method for preparing the Ni-NC supported copper nanosheet catalyst according to claim 1, characterized in that, The concentration of potassium bicarbonate in the CO2-saturated potassium bicarbonate solution is 0.1 M; and / or, the voltage of the electrochemical topological reduction is -0.9 V, and the time is 1 h.

9. A Ni-NC supported copper nanosheet catalyst prepared by the method according to any one of claims 1 to 8.

10. The application of the Ni-NC supported copper nanosheet catalyst of claim 9 in the electrocatalytic reduction of carbon dioxide to ethylene catalyst.

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