Cu-based alloy membrane catalyst as well as preparation method and application thereof

Abstract

The invention discloses a Cu-based alloy membrane catalyst as well as a preparation method and application thereof, and belongs to the technical field of CO2 reduction electro-catalysis. According to the method, the ion beam deposition technology and the HCl or HCl + FeCl3 system are combined, electrochemical etching is conducted on the Cu-Ag alloy film obtained through ion beam deposition, the Cu-based alloy film catalyst with the lamellar or nanocubic surface is prepared, and the electro-catalytic performance of the CO2 reduction reaction on the surface of the film catalyst is effectively improved.

Description

Technical Field

[0001] The present invention relates to a Cu-based alloy film catalyst, a preparation method thereof and an application thereof, belonging to the technical field of CO 2 electrocatalytic reduction technology. Background Technique

[0002] With the increasingly serious problem of global climate change, reducing greenhouse gas emissions has become a common goal of governments and research institutions around the world. CO 2 As one of the main greenhouse gases, it is widely emitted and accumulates in the atmosphere, profoundly affecting the global climate. To address this challenge, the technology of CO 2 capture and storage has become an important research direction. Especially the CO 2 electrocatalytic reduction technology, by converting CO 2 into valuable chemicals and fuels, can not only effectively reduce the concentration of CO 2 but also provide sustainable solutions for the energy industry.

[0003] CO 2 electroreduction technology reduces CO 2 to a series of useful chemical products through electrochemical reactions, such as CO, CH 4 and C 2 H 4 etc., and has the advantages of simple operation, high energy conversion efficiency and resource recycling. During the reduction reaction process, the selection and optimization of the catalyst are crucial for improving the CO 2 electroreduction efficiency and selectivity. Cu-based catalysts have become a current research hotspot due to their unique electronic structure and the ability to regulate the CO 2 reduction intermediate products.

[0004] The application of Cu-based catalysts in CO 2 electroreduction has received wide attention, especially in the reduction of CO 2 to products such as CO and CH 4 etc., showing excellent catalytic activity. Compared with other metal catalysts, Cu can not only provide a suitable reaction path but also regulate the electron transfer process, significantly improving the CO 2 reduction efficiency. In addition, Cu-based alloy catalysts are alloyed by introducing other metal elements (such as Ag, Au, Rh, etc.), further enhancing the catalytic performance, improving the stability and selectivity, and expanding their application potential in CO 2 electroreduction.

[0005] In the preparation of Cu-based alloy thin films, Chinese Patent CN116742008A uses a liquid-phase reduction method to obtain CuAg alloy nanoparticles, which enhances the conductivity of the catalyst. The surface is needle-like and fluffy, but the morphology is irregular, and the synthesis process is difficult to control with poor reproducibility. Chinese Patent CN103509528B also uses the liquid-phase reduction method to obtain Cu@Ag-SiO 2 nano high-temperature materials with uniform size, but its core-shell structure makes the preparation process relatively complex. Summary of the Invention

[0006] To overcome the problems in the background art, the purpose of the present invention is to provide a Cu-based alloy film catalyst, its preparation method and application, to prepare nano-cubes or lamellar Cu-based alloy film catalysts, significantly improving the CO 2 electrocatalytic performance, and having controllable, regular morphology and good reproducibility.

[0007] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0008] A preparation method of a Cu-based alloy film catalyst, comprising the following steps:

[0009] (1) Clean the surface of the carbonaceous carrier to obtain a clean and tidy carbonaceous carrier;

[0010] (2) Place the cleaned carbonaceous carrier on the ion beam sputtering sample stage, and then install the Ag target and Cu target on the target stage. First, perform auxiliary cleaning, and then perform ion beam sputtering to obtain a Cu-based alloy thin film;

[0011] (3) Put the Cu-based alloy thin film into an HCl solution or a mixed solution of HCl and FeCl 3 for electrochemical corrosion to obtain a Cu-based alloy film catalyst.

[0012] More preferably, the carbonaceous carrier is graphite fiber cloth or carbon paper.

[0013] More preferably, the surface cleaning includes: putting the carbonaceous carrier into a 0.5M H 2 SO 4 solution for ultrasonic cleaning for 15 min, then putting it into acetone for ultrasonic cleaning for 15 min, then putting it into water for ultrasonic cleaning for 15 min, and finally soaking it in absolute ethanol for 2 min. Take out the carbonaceous carrier and dry it to obtain a clean and tidy carbonaceous carrier.

[0014] More preferably, the parameters of the auxiliary cleaning include: the heating temperature is 200 °C, the cleaning is carried out at a vacuum degree of 6×10 -4 ~8×10 -4 Pa, the cleaning time is 10 - 15 min, and the cleaning gas is N2 and Ar.

[0015] More preferably, the parameters of the ion beam sputtering include: the atmosphere of the ion beam sputtering is Ar, and the flow rate of Ar is 5 sccm; the screen voltage is 2.0 - 2.2 KV, the beam current is 55 - 65 mA, the cathode current is 16 - 18 A, the anode voltage is 40 - 50 V, the time is 15 - 20 min, and the vacuum degree is 1.3×10 -2 ~1.5×10 -2 Pa.

[0016] The ion beam sputtering parameters of the present invention must be within the scope defined by the present invention to enable the CuAg alloy morphology of the finally prepared material to be regular nanocubes or regular lamellar shapes, and the electrical conductivity and CO 2 electrocatalytic performance of the material are significantly improved.

[0017] More preferably, the concentration of the HCl solution is 0.05 - 0.1 mol / L; the molar amount of hydrochloric acid and FeCl 3 in the mixed solution of HCl and FeCl 3 is 20:1.

[0018] More preferably, the temperature of the electrochemical corrosion is 25 - 45 °C, the corrosion time is 20 - 50 S, and the potential is 0.1 - 0.2 V.

[0019] The present invention also protects the Cu-based alloy film catalyst prepared by the preparation method of the Cu-based alloy film catalyst.

[0020] More preferably, when the corrosion solution is an HCl solution, the Cu-Ag alloy on the carbon-based carrier of the Cu-based alloy film catalyst is nanocubes; when the corrosion solution is a mixed solution of HCl and FeCl 3 the Cu-Ag alloy on the carbon-based carrier of the Cu-based alloy film catalyst is a lamellar structure.

[0021] The present invention also protects the application of the Cu-based alloy film catalyst in the electrocatalytic CO 2 reduction.

[0022] The beneficial effects of the present invention: The present invention uses an ion beam deposition technique to prepare a Cu-Ag alloy thin film, and combines HCl or an HCl + FeCl 3 system to etch the Cu-Ag alloy thin film, which can accurately control the preparation of a Cu-based alloy film catalyst with a lamellar or nanocube Cu-Ag alloy on the carbonaceous carrier, effectively increasing the electrocatalytic performance of the film catalyst for the CO 2 reduction reaction. Description of the Drawings

[0023] Figure 1 LSV diagrams of the nano-cubic or lamellar Cu-based alloy film catalysts prepared in Examples 1-4.

[0024] Figure 2 LSV diagrams of the Cu-based alloy thin film catalysts prepared in Comparative Examples 1-7.

[0025] Figure 3 SEM diagram of the nano-cubic Cu-based alloy film catalyst prepared in Example 2.

[0026] Figure 4 SEM diagram of the lamellar Cu-based alloy film catalyst prepared in Example 3.

[0027] Figure 5 SEM diagram of the lamellar Cu-based alloy film catalyst prepared in Example 4.

[0028] Figure 6 SEM diagram of the Cu-based alloy thin film catalyst prepared in Comparative Example 3.

[0029] Figure 7 SEM diagram of the Cu-based alloy film catalyst prepared in Comparative Example 4.

[0030] Figure 8 SEM diagram of the Cu-based alloy film catalyst prepared in Comparative Example 5.

[0031] Figure 9 SEM diagram of the Cu-based alloy film catalyst prepared in Comparative Example 6.

[0032] Figure 10 SEM diagram of the Cu-based alloy film catalyst prepared in Comparative Example 7. Detailed implementation manners

[0033] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] In the examples and comparative examples of the present invention, chemical reagents not described were all used for experiments with commercially available analytical pure reagents.

[0035] Example 1

[0036] A preparation method of a Cu-based alloy film catalyst includes the following steps:

[0037] (1) Put a 10×10 cm graphite fiber cloth into a 0.5 M H 2 SO 4 solution and ultrasonically clean it for 15 min; then put it into acetone and deionized water respectively for ultrasonic cleaning for 15 min, and finally soak it in absolute ethanol for 2 min for dehydration treatment, take it out and dry it.

[0038] (2) Place the cleaned graphite fiber cloth on the ion beam sputtering sample stage, then install the Ag target and Cu target on the target stage. Heat the sample to 200 °C, evacuate to 7×10 -4 Pa, clean for 10 min, and the cleaning gas is N 2 and Ar. After cleaning, introduce 5 sccm of Ar, set the screen voltage to 2 kV, beam current to 55 mA, cathode current to 17 A, anode voltage to 50 V, and the vacuum degree to 1.3×10 -2 Pa, generate an ion beam to bombard the Cu target and Ag target for 15 min, and anneal and cool to obtain a Cu-Ag alloy film.

[0039] (3) Cut the obtained Cu-Ag alloy film into a 2×2 cm specimen, immerse it in a 0.1 M HCl solution for electrochemical corrosion, with a corrosion temperature of 35 °C, a time of 30 s, and a potential of 0.2 V, to obtain a nano-cubic Cu-based alloy film catalyst.

[0040] Example 2

[0041] A preparation method of a Cu-based alloy film catalyst, comprising the following steps:

[0042] (1) Place a 10×10 cm graphite fiber cloth into a 0.5 M H 2 SO 4 solution and ultrasonically clean for 15 min; then place it in acetone and deionized water respectively and ultrasonically clean for 15 min, and finally soak it in absolute ethanol for 2 min for dehydration treatment, take it out and dry it.

[0043] (2) Place the cleaned graphite fiber cloth on the ion beam sputtering sample stage, then install the Ag target and Cu target on the target stage. Heat the sample to 200 °C, evacuate to 6×10 -4 Pa, clean for 15 min, and the cleaning gas is N 2 and Ar. After cleaning, introduce 5 sccm of Ar, set the screen voltage to 2 kV, beam current to 65 mA, cathode current to 16 A, anode voltage to 40 V, and the vacuum degree to 1.5×10 -2 Pa, generate an ion beam to bombard the Cu target and Ag target for 20 min, and anneal and cool to obtain a Cu-Ag alloy film.

[0044] (3) Cut the obtained Cu-Ag alloy film into a 2×2 cm specimen, immerse it in a 0.075 M HCl solution for electrochemical corrosion, with a corrosion temperature of 25 °C, a time of 30 s, and a potential of 0.2 V, to obtain a nano-cubic Cu-based alloy film catalyst.

[0045] According to Figure 3It can be seen that in the microscopic morphology of the Cu-Ag alloy on the graphite fiber cloth prepared in Example 2, more than 90% are nanocubes. The nanocubes are evenly distributed, with regular shapes and good dispersion. The particle surfaces are relatively rough, which helps to form more active sites, thereby improving the electrocatalytic performance.

[0046] Example 3

[0047] A preparation method of a Cu-based alloy film catalyst includes the following steps:

[0048] (1) Place a 10×10 cm graphite fiber cloth into a 0.5 M H 2 SO 4 solution and ultrasonically clean it for 15 min; then place it into acetone and deionized water respectively and ultrasonically clean it for 15 min. Finally, soak it in absolute ethanol for 2 min for dehydration treatment, take it out and dry it.

[0049] (2) Place the cleaned graphite fiber cloth on an ion beam sputtering sample stage, and then install an Ag target and a Cu target on the target stage. Heat the sample to 200 °C, evacuate to 8×10 -4 Pa, and clean for 10 min. The cleaning gas is N 2 and Ar. After cleaning, introduce 5 sccm of Ar, set the screen voltage to 2.2 kV, the beam current to 60 mA, the cathode current to 16 A, the anode voltage to 45 V, and the vacuum degree to 1.5×10 -2 Pa, generate an ion beam to bombard the Cu target and the Ag target for 15 min, and anneal and cool to obtain a Cu-Ag alloy film.

[0050] (3) Cut the obtained Cu-Ag alloy film into 2×2 cm specimens, immerse them in a mixed solution of 0.05 M HCl and 0.0025 M FeCl 3 for electrochemical corrosion. The corrosion temperature is 45 °C, the time is 50 S, and the potential is 0.1 V to obtain a lamellar Cu-based alloy film catalyst.

[0051] Example 4

[0052] A preparation method of a Cu-based alloy film catalyst includes the following steps:

[0053] (1) Place a 10×10 cm graphite fiber cloth into a 0.5 M H 2 SO 4 solution and ultrasonically clean it for 15 min; then place it into acetone and deionized water respectively and ultrasonically clean it for 15 min. Finally, soak it in absolute ethanol for 2 min for dehydration treatment, take it out and dry it.

[0054] (2) Place the cleaned graphite fiber cloth on the ion beam sputtering sample stage, then install the Ag target and Cu target on the target stage, heat the sample to 200 °C, evacuate to 8×10 -4 Pa, clean for 20 min, and the cleaning gas is N 2 and Ar. After cleaning, introduce 5 sccm of Ar, set the screen voltage to 2.1 kV, the beam current to 65 mA, the cathode current to 18 A, the anode voltage to 45 V, and the vacuum degree to 1.4×10 -2 Pa, generate an ion beam to bombard the Cu target and Ag target for 20 min, and anneal and cool to obtain a Cu-Ag alloy film.

[0055] (3) Cut the obtained Cu-Ag alloy film into a 2×2 cm sample, immerse it in a mixed solution of 0.1 M HCl and 0.005 M FeCl 3 for electrochemical corrosion. The corrosion temperature is 45 °C, the time is 20 s, and the potential is 0.2 V to obtain a lamellar Cu-based catalyst.

[0056] According to Figures 4 - 5 it can be seen that Examples 3 and 4 show a lamellar structure, with a larger specific surface area and more active sites. The lamellar structure can also provide more channels for reactant molecules to enter the active sites, thereby improving the electrocatalytic reaction efficiency, especially in the CO 2 reduction reaction.

[0057] Comparative Example 1

[0058] The only difference between the preparation method of the Cu-based alloy film catalyst in this comparative example and Example 1 is that:

[0059] In step (2), only the Cu target is installed on the target stage to obtain a Cu film, and step (3) is not passed through.

[0060] Comparative Example 2

[0061] The only difference between the preparation method of the Cu-based alloy film catalyst in this comparative example and Example 1 is that:

[0062] In step (2), only the Ag target is installed on the target stage to obtain an Ag film, and step (3) is not passed through.

[0063] Comparative Example 3

[0064] The only difference between the preparation method of the Cu-based alloy film catalyst in this comparative example and Example 1 is that:

[0065] The Cu-Ag alloy film obtained in step (2) is not passed through step (3).

[0066] According to Figure 6It can be seen that the surface of Comparative Example 3 is relatively smooth, without obvious particles or porous structures, which is beneficial to the formation of flaky materials or nanocube materials through electrochemical etching. Such surface characteristics help to improve the conductivity or mechanical strength of the materials, but are not conducive to the formation of active sites, and their electrocatalytic performance is relatively low.

[0067] Comparative Example 4

[0068] The only difference between the preparation method of the Cu-based alloy film catalyst in this comparative example and that in Example 1 is that:

[0069] In step (3), the Cu-based alloy thin film was immersed in 0.01 M FeCl 3 solution for electrochemical corrosion.

[0070] According to Figure 7 It can be seen that the material morphologies prepared on the graphite fiber cloth in Comparative Example 4 are inconsistent, the particle sizes are uneven, and there are irregular and sharp particles and crystalline structures on the graphite fiber cloth, resulting in uneven contact between the electrolyte and the electrode surface, and it is also easy to form an unstable electrochemical interface, reducing the charge transfer efficiency and resulting in poor stability of the membrane catalyst.

[0071] Comparative Example 5

[0072] The only difference between the preparation method of the Cu-based alloy film catalyst in this comparative example and that in Example 1 is that:

[0073] In step (3), the 0.1 M HCl solution was replaced with a 0.1 M nitric acid solution.

[0074] According to Figure 8 It can be seen that the surface of the material prepared on the graphite fiber cloth in Comparative Example 5 presents a regular crystal morphology with obvious geometric features, especially the larger crystal parts with relatively straight edges. However, the particle sizes are uneven, and there is a mixture of larger crystals and small particles. This uneven size distribution leads to instability in the electrochemical performance, restricting the charge transfer and the progress of the reaction.

[0075] Comparative Example 6

[0076] The only difference between the preparation method of the Cu-based alloy film catalyst in this comparative example and that in Example 1 is that:

[0077] In step (3), the obtained Cu-Ag alloy film was cut into a 2×2 cm specimen and immersed in 0.1 M HCl solution at 25 °C for 12 h.

[0078] According to Figure 9It can be seen that the surface of the material prepared on the graphite fiber cloth described in Comparative Example 6 shows an obvious polygonal shape, with a relatively regular morphology, and the surfaces of most particles are smooth. This morphology inhibits the electrochemical reaction and reduces the rate of the electrochemical reaction.

[0079] Comparative Example 7

[0080] The only difference between the preparation method of a Cu-based alloy film catalyst in this comparative example and Example 1 is as follows:

[0081] (1) Place a 10×10 cm graphite fiber cloth into a 0.5 M H 2 SO 4 solution and ultrasonically clean it for 15 min; then place it into acetone and deionized water respectively and ultrasonically clean it for 15 min. Finally, soak it in absolute ethanol for 2 min for dehydration treatment, take it out and dry it.

[0082] (2) Place the cleaned graphite fiber cloth on the electron evaporation sample stage, and then install a Cu target and an Ag target on the target stage. Heat the sample stage to 300 °C, evacuate to 6×10 -4 Pa, and clean for 10 min. The cleaning gas is N 2 and Ar. Set the screen voltage to 3 kV, the beam current to 100 mA, the cathode current to 17 A, and the anode voltage to 60 V. Generate an electron beam to bombard the Cu target and the Ag target for 5 min, and anneal and cool to obtain a Cu-Ag alloy thin film.

[0083] (3) Cut the obtained Cu-Ag alloy film into 2×2 cm specimens, immerse them in a 0.1 M HCl solution for electrochemical corrosion. The corrosion temperature is 35 °C, the time is 30 s, and the potential is 0.2 V to obtain a Cu-based catalyst.

[0084] According to Figure 10 It can be seen that the surface of the material prepared on the graphite fiber cloth described in Comparative Example 7 shows a morphology of microparticle agglomeration. Its surface is irregular and too rough, resulting in uneven contact between the electrolyte and the electrode, thus affecting the uniform distribution of the current, and further reducing the efficiency of the electrochemical reaction. Moreover, the agglomeration will also affect the diffusion of the electrolyte and the transfer of ions, causing the flow of reactants between particles to be restricted, thereby reducing the electrochemical performance.

[0085] Effect Example

[0086] Test samples: Examples 1 to 4 and Comparative Examples 1 to 7.

[0087] Test method:

[0088] (1) Characterize the surface morphology of the test samples by scanning electron microscopy (SEM).

[0089] (2) Electrochemical characterization was carried out in a standard three - electrode system. The prepared catalyst was used as the working electrode, a graphite rod as the counter electrode, Ag / AgCl as the reference electrode, and the electrolytic cell was a traditional H - type electrolytic cell. Linear sweep voltammetry (LSV) was used to characterize the activity of the catalyst. The scanning range of the LSV test was - 0.6 - 0 V (versus reversible hydrogen electrode), and the scanning rate was 10 mV / s. The results are shown in Table 1 and Figures 1 - 2 .

[0090] Table 1

[0091] Sample <![CDATA[Current density (mAcm -2 )]]> Example 1 -3.91 Example 2 -4.33 Example 3 -5.07 Example 4 -4.63 Comparative Example 1 -1.20 Comparative Example 2 -1.60 Comparative Example 3 -1.86 Comparative Example 4 -2.46 Comparative Example 5 -2.00 Comparative Example 6 -1.73 Comparative Example 7 -3.04

[0092] According to Figures 1 - 2 and Table 1, compared with Comparative Examples 1 - 7, Examples 1 - 4 all showed regular nano - cube particles or lamellar structures on the surface, which could effectively improve the electrocatalytic reaction efficiency, especially in the CO 2 reduction reaction, showing outstanding performance.

[0093] It can be seen from the SEM images that the surface of Comparative Example 3 was relatively smooth, and no obvious particles or porous structures were observed. Such surface characteristics may help improve the conductivity or mechanical strength of the material, but are not conducive to the formation of active sites, and its electrocatalytic performance is relatively low. Example 2 presented uniformly distributed nano - cube particles with regular shapes and good dispersion. The surface of the particles was relatively rough, which may help form more active sites, thus enhancing the electrocatalytic performance. Examples 3 and 4 showed lamellar structures with a large specific surface area and more active sites. The lamellar structure could also provide more channels for reactant molecules to enter the active sites, thereby improving the electrocatalytic reaction efficiency, especially in the CO 2 reduction reaction, showing outstanding performance. Comparative Examples 4 - 7 had problems such as inconsistent morphologies, uneven size distributions, and particle agglomeration, and did not show good CO 2 reduction performance. It can be seen from the LSV graphs that both Example 2 and Example 3 showed excellent performance, which also verified that their regular nano - cube particles and lamellar structures could effectively improve the electrocatalytic reaction efficiency, especially in reactions such as CO 2 reduction, showing outstanding performance.

[0094] Finally, it should be noted that the above - mentioned preferred embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail through the above - mentioned preferred embodiments, those skilled in the art should understand that various changes can be made in terms of form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing a Cu-based alloy film catalyst, characterized in that: The following steps are involved: (1) cleaning the surface of the carbon support to obtain a clean and tidy carbon support; (2) placing the cleaned carbonaceous carrier on an ion beam sputtering sample stage, then installing an Ag target and a Cu target on the target stage, first performing auxiliary cleaning, and then performing ion beam sputtering to obtain a Cu-based alloy film; (3) The Cu-based alloy film is placed in an HCl solution or a mixed solution of HCl and FeCl3 for electrochemical corrosion to obtain a Cu-based alloy film catalyst.

2. The method for preparing the Cu-based alloy film catalyst according to claim 1, characterized in that: The carbonaceous carrier is graphite fiber cloth or carbon paper.

3. The method for preparing the Cu-based alloy film catalyst according to claim 1, characterized in that: The surface cleaning conditions include: placing the carbon carrier in a 0.5MH2SO4 solution for ultrasonic cleaning for 15 minutes, then placing it in acetone for ultrasonic cleaning for 15 minutes, then placing it in water for ultrasonic cleaning for 15 minutes, and finally soaking it in ethanol for 2 minutes, taking out the carbon carrier and drying it to obtain a clean and tidy carbon carrier.

4. The method for preparing the Cu-based alloy film catalyst according to claim 1, characterized in that: The auxiliary cleaning parameters include: heating temperature of 200°C, vacuum degree of 6×10 -4 ~8×10 -4 The cleaning is carried out at 4000 rpm for 10 to 15 minutes using N2 and Ar as the cleaning gases.

5. The method for preparing the Cu-based alloy film catalyst according to claim 1, characterized in that: The parameters of the ion beam sputtering include: the atmosphere is Ar, the flow rate of Ar is 5.0 sccm, the screen voltage is 2-2.2 KV, the beam current is 55-65 mA, the cathode current is 16-18 A, the anode voltage is 40-50 V, the time is 15-20 min, and the vacuum degree is 1.3×10 -2 ~1.5×10 -2 Pa.

6. The method for preparing the Cu-based alloy film catalyst according to claim 1, characterized in that: The concentration of the HCl solution is 0.05-0.1 mol / L; the amount of hydrochloric acid and FeCl3 in the mixed solution of HCl and FeCl3 is 20:

1.

7. The method for preparing the Cu-based alloy film catalyst according to claim 1, characterized in that: The temperature of the electrochemical corrosion is 25-45° C., the corrosion time is 20-50S, and the potential is 0.1-0.2V.

8. The Cu-based alloy film catalyst prepared according to the method for preparing the Cu-based alloy film catalyst according to any one of claims 1 to 7.

9. The Cu-based alloy film catalyst according to claim 8, characterized in that: The surface of the Cu-based alloy film catalyst presents a lamellar or nanocube morphology.

10. Use of the Cu-based alloy film catalyst according to claim 9 in electrocatalytic CO2 reduction.

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