An ionic liquid modified Cu-based catalyst and its preparation method and application
By modifying Cu nanowires with ionic liquid groups to form Cu-based catalysts with coordinate bonds, the problem of selectively producing high-value-added products in the carbon dioxide reduction reaction was solved, and the efficient reduction of carbon dioxide to ethylene was achieved.
Patent Information
- Application Number
- CN202410945633.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-15
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2044-07-15
AI Technical Summary
Existing technologies have low efficiency in converting carbon dioxide into high-value-added products, especially in the kinetics of selectively producing energy-rich multi-carbon products in carbon dioxide reduction reactions, and the carbon-carbon coupling process has high barriers.
A highly selective carbon dioxide reduction photocatalyst was constructed by combining in-situ grown Cu nanowires with ionic liquid groups, through the formation of coordination bonds between nitrogen in the imidazole ring and copper.
It significantly reduced the barrier to carbon-carbon coupling reaction and improved the activation efficiency of carbon dioxide reduction process, resulting in an ethylene selectivity of 96.7% under 450nm monochromatic light irradiation.
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Figure CN118988403B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, and relates to an ionic liquid modified Cu-based catalyst, its preparation method and application. Background Technology
[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.
[0003] The continued consumption of traditional fossil fuels has led to a severe energy crisis and global warming over the past few decades. Converting atmospheric carbon dioxide into high-value products can reduce both carbon dioxide concentration and emissions, thus simultaneously addressing environmental problems and energy shortages. Solar-driven photocatalysis to directly convert carbon dioxide and water into high-value hydrocarbon feedstocks is a promising approach. However, similar to various proton-coupled electron transfer processes, the selective production of energy-rich multi-carbon products from carbon dioxide reduction reactions is kinetically unfavorable. This is because carbon dioxide molecules are relatively stable and difficult to activate, and the carbon-carbon coupling process has a high barrier, making the reduction of carbon dioxide to high-value products difficult. Therefore, the efficiency of converting carbon dioxide into high-value products remains relatively low. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide an ionic liquid-modified Cu-based catalyst, its preparation method, and its applications. The present invention utilizes in-situ grown Cu nanowires as the active component and combines the catalyst with an ionic liquid component, thereby constructing a highly selective carbon dioxide reduction photocatalyst for ethylene.
[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:
[0006] In a first aspect, the present invention provides an ionic liquid-modified Cu-based catalyst, comprising Cu nanowires and ionic liquid groups modified on the surface of the Cu nanowires, wherein the Cu nanowires and the ionic liquid groups are connected by coordination bonds between nitrogen and copper in an imidazole ring.
[0007] In some embodiments, the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate or 1-butyl-3-methylimidazolium tetrafluoroborate.
[0008] Preferably, in the Cu-based catalyst modified with ionic liquid, the volume percentage of the ionic liquid is 0.1 vol.% to 20 vol.%.
[0009] More preferably, in the ionic liquid-modified Cu-based catalyst, the volume percentage of the ionic liquid is 1 vol.% to 20 vol.%.
[0010] More preferably, in the Cu-based catalyst modified with ionic liquid, the volume percentage of the ionic liquid is 5 vol.% to 15 vol.%.
[0011] Secondly, the present invention provides a method for preparing the Cu-based catalyst modified by the ionic liquid, comprising the following steps:
[0012] After cleaning the foamed copper, it is anodized to obtain in-situ grown Cu(OH)2;
[0013] Cu(OH)2-grown copper foam was annealed in an argon-hydrogen atmosphere to obtain in-situ grown Cu nanowires.
[0014] By modifying Cu nanowires with ionic liquids, Cu-based catalysts modified with ionic liquids are obtained.
[0015] In some embodiments, the liquid used for anodizing is 2-4M KOH, and the oxidation time is 20-40 minutes.
[0016] Preferably, the liquid used for anodizing is 2.5-4.5M KOH, and the oxidation time is 25-35 minutes.
[0017] In some embodiments, the annealing temperature is 250-350°C and the annealing time is 1.5-2.5 hours.
[0018] Preferably, the annealing temperature is 270-320℃ and the annealing time is 1.7-2.2h.
[0019] In some embodiments, copper foam with in-situ grown copper nanowires is immersed in an aqueous ionic liquid for a set time to obtain an ionic liquid-modified Cu-based catalyst.
[0020] Preferably, in the aqueous solution of the ionic liquid, the volume percentage of the ionic liquid is 0.1 vol.% to 20 vol.%, preferably 5 vol.%.
[0021] Preferably, the immersion temperature is 20-50℃ and the immersion time is 1-10h.
[0022] Further preferably, the impregnation temperature is 20-35℃.
[0023] Thirdly, the present invention provides the application of the Cu-based catalyst modified with the ionic liquid in the catalytic reduction of carbon dioxide to produce ethylene.
[0024] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:
[0025] (1) The use of ionic liquids effectively promotes the activation of carbon dioxide molecules, making the carbon dioxide reduction process easier. At the same time, the reaction barrier of the carbon-carbon coupling rate-determining step is greatly reduced.
[0026] (2) The carbon dioxide reduction photocatalyst prepared in this invention exhibits high selectivity in the reaction of carbon dioxide reduction to ethylene. Under 450 nm monochromatic light irradiation, the ethylene selectivity reaches 96.7% in 5 vol.% ionic liquid, showing broad prospects for practical applications.
[0027] (3) The Cu nanowires grown in situ using copper foam as a template in this invention have an ultra-large specific surface area and provide abundant reactive sites, which can effectively promote the efficient photocatalytic reduction of carbon dioxide. Attached Figure Description
[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0029] Figure 1 (a) X-ray diffraction (XRD) image and (b) scanning electron microscope image of the Cu-based catalyst in Example 1;
[0030] Figure 2 The X-ray photoelectron spectra of the Cu-based catalyst in Example 1 are shown, where (a) is the N1s spectrum and (b) is the Cu 2p spectrum.
[0031] Figure 3 The UV-Vis diffuse reflectance spectrum of the Cu-based catalyst in Example 1;
[0032] Figure 4 The Fourier transform infrared spectrum of the Cu-based catalyst in Example 1;
[0033] Figure 5 The following are examples of the catalyst in Example 2 in a carbon dioxide atmosphere: (a) wavelength dependence; (b) ionic liquid concentration dependence; (c) comparison of products in argon and carbon dioxide atmospheres.
[0034] Figure 6 This is a graph showing the carbon source detection of the catalyst in Example 2. Detailed Implementation
[0035] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0036] The present invention will be further described below with reference to the embodiments.
[0037] Example 1
[0038] Preparation of Cu-based catalyst: Copper foam was placed in a 3M KOH solution and anolyzed using an electrochemical workstation with a carbon rod as the counter electrode. After oxidation for about 30 minutes, in-situ grown copper hydroxide nanowires were obtained. The copper hydroxide was washed, dried, and annealed in an argon-hydrogen atmosphere. In a 10% argon-hydrogen atmosphere, the temperature was slowly increased at 1℃ / min to 300℃ and maintained for 120 minutes to finally obtain in-situ grown Cu nanowires.
[0039] like Figure 1 As shown, no other characteristic peaks appeared in the XRD pattern of the Cu catalyst except for Cu, indicating that Cu was completely reduced and there was no copper hydroxide residue.
[0040] like Figure 2 As shown, nitrogen and Cu in the ionic liquid are bonded together by coordinate bonds.
[0041] like Figure 3 As shown, the plasma resonance absorption peak of Cu did not shift significantly before and after modification, which also proves that the photocatalytic process is driven by hot carriers generated by the Cu plasma effect.
[0042] like Figure 4 As shown, the coordination between Cu and nitrogen atoms is clearly visible, a composition not present in pristine Cu.
[0043] Example 2
[0044] Application of the Cu-based catalyst modified with ionic liquid prepared in Example 1 in electrocatalytic carbon dioxide reduction:
[0045] In situ grown Cu nanowires were fixed in a copper foam onto an electrode clamp, and a carbon dioxide reduction experiment was conducted using monochromatic light of a specific wavelength.
[0046] The specific experimental steps are as follows: 45 ml of 5 vol.% 1-ethyl-3-methylimidazolium tetrafluoroborate aqueous solution was placed in a single-cell reactor. Copper foam with Cu nanowires grown in situ was fixed on an electrode clamp and placed in the ionic liquid aqueous solution. At the same time, magnetic particles were added to the solution to facilitate the desorption of the product gas. A 300W xenon lamp and various wavelength bandpasses were used as light sources to conduct a photocatalytic CO2 reduction experiment.
[0047] like Figure 5As shown in Figure a, under monochromatic light irradiation at various wavelengths, the catalyst exhibits optimal performance at 450 nm, where the ethylene product selectivity reaches 96.7%. Meanwhile, as the concentration of the ionic liquid increases (as shown in Figure b), the catalytic performance also shows a trend of first increasing and then decreasing, with 5 vol.% being the optimal concentration. Furthermore, as shown in Figure c, no ethylene product was detected in an argon atmosphere.
[0048] like Figure 6 As shown, replace CO2 with 13 Carbon source identification of CO2 reveals that the source is clearly visible in the spectrum. 13 The peak of C2H4 is clearly visible, as are the fragment peaks at other locations.
[0049] Example 3
[0050] Preparation of Cu-based catalyst: Copper foam was placed in a 3M KOH solution and anolyzed using an electrochemical workstation with a carbon rod as the counter electrode. After oxidation for about 30 minutes, in-situ grown copper hydroxide nanowires were obtained. The copper hydroxide was washed, dried, and annealed in an argon-hydrogen atmosphere. In a 10% argon-hydrogen atmosphere, the temperature was slowly increased at 1℃ / min to 300℃ and maintained for 120 minutes to finally obtain in-situ grown Cu nanowires.
[0051] Cu nanowires grown in situ were impregnated in 1 vol.% 1-ethyl-3-methylimidazolium tetrafluoroborate for 5 h at room temperature to obtain an ionic liquid-modified Cu-based catalyst.
[0052] Example 4
[0053] Preparation of Cu-based catalyst: Copper foam was placed in a 3M KOH solution and anolyzed using an electrochemical workstation with a carbon rod as the counter electrode. After oxidation for about 30 minutes, in-situ grown copper hydroxide nanowires were obtained. The copper hydroxide was washed, dried, and annealed in an argon-hydrogen atmosphere. In a 10% argon-hydrogen atmosphere, the temperature was slowly increased at 1℃ / min to 300℃ and maintained for 120 minutes to finally obtain in-situ grown Cu nanowires.
[0054] Cu nanowires grown in situ are impregnated in 10 vol.% 1-butyl-3-methylimidazolium tetrafluoroborate at room temperature to obtain an ionic liquid-modified Cu-based catalyst, which can be used for the photocatalytic reduction of CO2.
[0055] Example 5
[0056] Preparation of Cu-based catalyst: Copper foam was placed in a 3M KOH solution and anolyzed using an electrochemical workstation with a carbon rod as the counter electrode. After oxidation for about 30 minutes, in-situ grown copper hydroxide nanowires were obtained. The copper hydroxide was washed, dried, and annealed in an argon-hydrogen atmosphere. In a 10% argon-hydrogen atmosphere, the temperature was slowly increased at 1℃ / min to 300℃ and maintained for 120 minutes to finally obtain in-situ grown Cu nanowires.
[0057] Cu nanowires grown in situ are impregnated in 20 vol.% 1-butyl-3-methylimidazolium tetrafluoroborate at room temperature to obtain an ionic liquid-modified Cu-based catalyst, which can be used for the photocatalytic reduction of CO2.
[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A Cu-based catalyst modified with an ionic liquid, characterized in that: It includes Cu nanowires and ionic liquid groups modified on the surface of Cu nanowires. The Cu nanowires and ionic liquid groups are connected by coordination bonds between the nitrogen in the imidazole ring and the copper. The ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate or 1-butyl-3-methylimidazolium tetrafluoroborate; The preparation method of the Cu-based catalyst modified with the ionic liquid includes the following steps: After cleaning the foamed copper, it is anodized to obtain in-situ grown Cu(OH)2; Cu(OH)2-grown copper foam was annealed in an argon-hydrogen atmosphere to obtain in-situ grown Cu nanowires. By modifying Cu nanowires with ionic liquids, Cu-based catalysts modified with ionic liquids are obtained.
2. The Cu-based catalyst modified with an ionic liquid according to claim 1, characterized in that: In the Cu-based catalyst modified with ionic liquid, the volume percentage of ionic liquid is 0.1 vol.%-20 vol.%.
3. The Cu-based catalyst modified with an ionic liquid according to claim 2, characterized in that: The volume percentage of ionic liquids is 1 vol.%–20 vol.%.
4. The Cu-based catalyst modified with an ionic liquid according to claim 3, characterized in that: The volume percentage of ionic liquids is 5 vol.%–15 vol.%.
5. The Cu-based catalyst modified with an ionic liquid according to claim 1, characterized in that: The liquid used for anodizing is 2-4M KOH, and the oxidation time is 20-40 minutes.
6. The Cu-based catalyst modified with an ionic liquid according to claim 5, characterized in that: The liquid used for anodizing is 2.5-4M KOH, and the oxidation time is 25-35 minutes.
7. The Cu-based catalyst modified with an ionic liquid according to claim 1, characterized in that: The annealing temperature is 250-350℃, and the annealing time is 1.5-2.5h.
8. The Cu-based catalyst modified with an ionic liquid according to claim 7, characterized in that: The annealing temperature is 270-320℃, and the annealing time is 1.7-2.2h.
9. The Cu-based catalyst modified with an ionic liquid according to claim 1, characterized in that: By immersing copper foam with in-situ grown copper nanowires in an ionic liquid for a set time, an ionic liquid-modified Cu-based catalyst can be obtained.
10. The Cu-based catalyst modified with an ionic liquid according to claim 9, characterized in that: In aqueous solutions of ionic liquids, the volume percentage of the ionic liquid is 0.1 vol.%–20 vol.%.
11. The Cu-based catalyst modified with an ionic liquid according to claim 10, characterized in that: The volume percentage of the ionic liquid is 5 vol.%.
12. The Cu-based catalyst modified with an ionic liquid according to claim 9, characterized in that: The immersion temperature is 20-50℃, and the immersion time is 1-10 hours.
13. The Cu-based catalyst modified with an ionic liquid according to claim 12, characterized in that: The immersion temperature is 20-35℃.
14. The use of the Cu-based catalyst modified with the ionic liquid according to any one of claims 1-13 in the catalytic reduction of carbon dioxide to produce ethylene.