Method for preparing high-stability Pd-based flexible carbon nanofiber membrane catalyst by femtosecond laser
The preparation of Pd-based flexible carbon nanofiber membrane catalysts by femtosecond laser technology solves the problem of easy aggregation of traditional Pd nanoparticles, and realizes a catalyst with high stability and high activity, which is suitable for ethanol electrocatalysis in fuel cells.
Patent Information
- Application Number
- CN202511774070.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional Pd nanoparticle-based catalysts are prone to aggregation, shedding, and poisoning during long-term operation, resulting in insufficient catalytic activity and stability, which limits their application in fuel cells.
A highly stable Pd-based flexible carbon nanofiber membrane catalyst was prepared using femtosecond laser. The carbon nanofiber membrane was treated with acid and Pd2+ was loaded using a femtosecond laser to achieve uniform dispersion and strong interaction of Pd nanoparticles on the carbon nanofiber membrane.
The nanoparticle dispersion and support interaction of Pd-based catalysts are improved, enhancing catalytic activity and stability, making them suitable for ethanol electrocatalysis and enabling them to maintain high performance over long periods in complex environments.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanomaterial preparation technology, and relates to a method for preparing highly stable Pd-based flexible carbon nanofiber membrane catalysts using femtosecond laser. Background Technology
[0002] With societal development, environmental and energy issues are receiving increasing attention, and global energy demand is rising. Developing new energy sources has become a development strategy for various countries. New, green, and efficient energy storage and conversion technologies, represented by fuel cells, have become a key focus of new energy research. Direct liquid fuel cells (DLFCs) are a type of fuel cell that uses liquid fuels (methanol, ethanol, formic acid, etc.). Their large-scale application is limited by the slow kinetics of anodic oxidation reactions (such as MOR, EOR, etc.) and cathodic reduction reactions (ORR).
[0003] Petrochemical metal (Pt) possesses excellent adsorption and dissociation properties for ethanol, making it the most commonly used catalytic metal in DLFC anodes. However, the cost of Pt is a major obstacle to the commercialization of fuel cell technology, and fluctuations in Pt's price directly affect the manufacturing cost of fuel cells. On the other hand, phosphorus d (Pd) exhibits similar catalytic performance to Pt, sharing the same face-centered cubic crystal structure and similar atomic size within the same group of elements in the periodic table, but at a significantly lower cost. Furthermore, Pd's unique resistance to CO poisoning makes it highly promising in the field of alcohol catalysis. Therefore, the research and development of abundant, inexpensive, highly active, and highly stable non-Pt-based catalysts is one of the most active research topics in the current new energy field.
[0004] Traditional Pd nanoparticle-based catalysts suffer from problems such as easy particle aggregation and weak interaction between the support and particles. During long-term operation, they are prone to agglomeration, shedding, and poisoning, all of which affect the catalytic activity and stability of the catalyst, limiting its further applications. Therefore, developing a novel, highly stable Pd-based catalyst is of significant research importance and application value. Summary of the Invention
[0005] To address the shortcomings of Pd-based nanoparticle catalysts, this invention proposes a synthetic method and process for preparing highly stable Pd-based flexible carbon nanofiber membrane catalysts using femtosecond laser technology. The Pd-based flexible carbon nanofiber membrane catalyst prepared by this method exhibits good nanoparticle dispersion, strong interaction between nanoparticles and the support, and excellent catalytic activity and stability.
[0006] The technical solution adopted in this invention is as follows:
[0007] A method for preparing highly stable Pd-based flexible carbon nanofiber membrane catalysts using femtosecond lasers, characterized by the following steps:
[0008] (1) Use fresh aqua regia to acid-impregnate the carbon nanofiber membrane. After acid impregnation, remove the carbon nanofiber membrane and vacuum dry it to remove the residual liquid on the surface to obtain the acid-impregnated carbon nanofiber membrane.
[0009] (2) Disperse PdCl2 in concentrated hydrochloric acid, dilute the solution, and obtain a PdCl2 precursor solution;
[0010] (3) The carbon nanofiber membrane obtained in step (1) is immersed in the PdCl2 precursor solution obtained in step (2). After immersion, the carbon nanofiber membrane is removed and vacuum dried to remove the residual liquid on the surface, thus obtaining the pretreated Pd-loaded membrane. 2+ Carbon nanofiber membranes;
[0011] (4) Use femtosecond laser scanning to scan the pre-processed load Pd from step (3). 2+ Pd-based carbon nanofiber membrane catalysts were obtained by constructing carbon nanofiber membranes.
[0012] Preferably, in step (1), each 4-6 ml of freshly prepared aqua regia corresponds to 1 cm 2 * 0.2mm (thickness) carbon nanofiber membrane, acid immersion for 4 ~ 6 h.
[0013] Preferably, in step (2), PdCl2 is dispersed in concentrated hydrochloric acid, and the solution is diluted with anhydrous ethanol, deionized water, or a mixture of anhydrous ethanol and deionized water to obtain a PdCl2 precursor solution. The volume ratio of concentrated hydrochloric acid, ethanol, and water in the PdCl2 precursor solution is 1:0 ~ 99:0 ~ 99, and the ethanol content is not 0, preferably 1:99:0. Each 0.1 mmol of PdCl2 is dispersed in 50 ~ 200 µl of concentrated hydrochloric acid.
[0014] Preferably, the soaking time in step (3) is 1 to 10 hours, and more preferably 5 hours.
[0015] The femtosecond pulsed laser in step (4) has a wavelength of 515 nm, a repetition frequency of 5000 Hz, a pulse width of 100 fs, and a spot size of 0.1 mm.
[0016] Preferably, the laser scanning processing scheme in step (4) is set to a laser scanning speed of 250 mm / s, a laser scanning spacing of 0.1 mm, cross scanning, and a laser power of 0.9 ~ 1.5 W.
[0017] The highly stable Pd-based flexible carbon nanofiber membrane catalyst obtained by this invention can be used for ethanol electrocatalysis, with the final products being carbon dioxide and water.
[0018] This method for preparing highly stable Pd-based flexible carbon nanofiber membrane catalysts using femtosecond lasers has the following advantages:
[0019] 1. Highly efficient processing method: Highly stable Pd-based flexible carbon nanofiber membrane catalysts are rapidly prepared using femtosecond laser high-speed scanning. This method is simple and efficient, possessing the advantages of rapid processing, clean ligand-free preparation, and environmental friendliness of laser nanomaterial preparation technology, and can achieve the efficient processing and preparation of large quantities of Pd-based flexible carbon nanofiber membrane catalysts.
[0020] 2. Accurate control of catalyst metal loading: By adjusting the acid immersion time of the carbon nanofiber membrane, as well as the pH value, concentration, dilution solution, and immersion time of the metal precursor solution, the catalyst metal loading on the carbon nanofiber membrane can be accurately controlled.
[0021] 3. Optimized laser parameters: By adjusting and optimizing the wavelength, power, spot size, scanning speed and scanning strategy of the femtosecond laser, the synthesis of Pd nanoparticles on carbon nanofiber membranes is ensured under optimal conditions, so that Pd nanoparticles and carbon nanofiber membranes generate a strong synergistic effect, thereby improving the synthesis efficiency and catalytic performance.
[0022] 4. Suitable for ethanol catalysis: The optimized Pd-based flexible carbon nanofiber membrane catalyst has high ethanol catalytic activity, as well as excellent stability and durability. It can maintain high performance for a long time in the complex working environment of fuel cells and effectively resist electrochemical corrosion and poisoning.
[0023] In summary, this method for preparing highly stable Pd-based flexible carbon nanofiber membrane catalysts using femtosecond lasers has advantages such as efficient processing, accurate control, optimized parameters, excellent performance, and superior stability. It is expected to have important applications and promote development in the field of catalysis and other related fields. Attached Figure Description
[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0025] Figure 1 This is a SEM image of the Pd-based flexible carbon nanofiber membrane catalyst prepared in Example 1 of this invention.
[0026] Figure 2 This is a TEM image of the Pd-based flexible carbon nanofiber membrane catalyst prepared in Example 1 of this invention.
[0027] Figure 3 This is a TEM image of the Pd-based flexible carbon nanofiber membrane catalyst prepared in Comparative Example 1 of this invention.
[0028] Figure 4This is a TEM image of the Pd-based flexible carbon nanofiber membrane catalyst prepared in Comparative Example 2 of this invention.
[0029] Figure 5 The above are Raman diagrams of the Pd-based flexible carbon nanofiber membrane catalysts prepared in Examples 1 to 3 of this invention.
[0030] Figure 6 The above are XRD patterns of the Pd-based flexible carbon nanofiber membrane catalysts prepared in Examples 1 to 3 of this invention.
[0031] Figure 7 The above are XPS images of the Pd-based flexible carbon nanofiber membrane catalysts prepared in Examples 1 to 3 of this invention.
[0032] Figure 8 Figure 1 shows the electrocatalytic performance test results of the Pd-based flexible carbon nanofiber membrane catalysts prepared in Examples 1-3 of this invention for ethanol. Figure 2 shows the test results of the samples in a three-electrode system in a mixed solution of 1M potassium hydroxide and 1M ethanol, using an Hg / HgO electrode as the reference electrode. The potential range of the cyclic voltammetry test was -0.85 to 0.25 V, and the scan rate was 50 mV / s.
[0033] Figure 9 Figures a and b show the ethanol electrocatalytic accelerated aging test and chronoamperometry test results of the Pd-based flexible carbon nanofiber membrane catalysts prepared in Examples 1-3 of this invention, respectively. Figure 2 shows the test results of the sample in a mixed solution of 1 M potassium hydroxide and 1 M ethanol in a three-electrode system. The Hg / HgO electrode was used as the reference electrode. The potential range of the accelerated aging test was -0.85 V to 0.25 V, the scan rate was 100 mV / s, and the potential of the chronoamperometry test was -0.25 V. Detailed Implementation
[0034] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.
[0035] Example 1:
[0036] A method for preparing highly stable Pd-based flexible carbon nanofiber membrane catalysts using femtosecond lasers includes the following steps:
[0037] (1) Use 5 ml of fresh aqua regia to soak 1 cm 2 * A 0.2 mm (thickness) carbon nanofiber membrane was acid-impregnated for 5 h, then removed and vacuum-dried for 30 min to remove residual liquid from the surface, resulting in an acid-impregnated carbon nanofiber membrane.
[0038] (2) Disperse 0.1 mmol PdCl2 in 100 µl of concentrated hydrochloric acid, and dilute the solution to 10 ml with anhydrous ethanol to obtain the precursor solution;
[0039] (3) The carbon nanofiber membrane obtained in step (1) is immersed in the precursor solution obtained in step (2). After immersion for 5 hours, the carbon nanofiber membrane is removed and vacuum dried for 30 minutes to remove residual liquid on the surface, thus obtaining the pretreated Pd-loaded membrane. 2+ Carbon nanofiber membranes;
[0040] (4) Preprocessing the load Pd using femtosecond laser scanning 2+ Pd-based carbon nanofiber membrane catalysts were obtained from carbon nanofiber membranes and used for electrochemical testing.
[0041] The femtosecond laser is a pulsed laser with a wavelength of 515 nm, a repetition rate of 5000 Hz, a pulse width of 100 fs, and a spot size of 0.1 mm.
[0042] The laser scanning processing scheme is set with a laser scanning speed of 250 mm / s, a laser scanning spacing of 0.1 mm, cross scanning, and a laser power of 1.2 W.
[0043] Figure 1 and Figure 2 The images show SEM and TEM images of the sample. It is clear from the images that the Pd nanoparticles on the carbon nanofiber membrane exhibit good dispersion and uniform particle size, with a particle size of 5–8 nm. The loading is approximately 30 µg / cm³. 2 .
[0044] Example 2:
[0045] Compared with Example 1, the difference is that the laser power in step (4) is 0.9 W, and the other conditions and steps are the same as in Example 1.
[0046] Example 3:
[0047] Compared with Example 1, the difference is that the laser power in step (4) is 1.5 W, and the other conditions and steps are the same as in Example 1.
[0048] Comparative Example 1:
[0049] Compared with Example 1, the difference is that the operation in step (1) is not performed, while the other conditions and steps are the same as in Example 1.
[0050] Figure 3The image is a TEM image of Comparative Example 1. It can be clearly seen from the image that the dispersion of Pd nanoparticles on the carbon nanofiber membrane is poor and the particle size is uneven. This is because the carbon nanofiber membrane was not pre-treated with acid, and there are not enough defect sites on the surface of the carbon nanofiber membrane to anchor the particle positions.
[0051] Comparative Example 2:
[0052] Compared with Example 1, the difference is that deionized water is used to dilute the solution in step (2), while the other conditions and steps are the same as in Example 1.
[0053] Figure 4 The image shown is a TEM image of Comparative Example 2. It clearly shows that the Pd nanoparticles on the carbon nanofiber membrane have a larger particle size, with the main particle size distribution range being 12-15 nm. This is due to the different ionization degrees of different solutions, leading to the increased size of the Pd nanoparticles. 2+ The adhesion to the carbon nanofiber membrane surface becomes stronger, and the nanoparticle size increases.
[0054] Performance testing
[0055] The ethanol catalytic performance of Examples 1-3 above was tested using a three-electrode system on an electrochemical workstation. The Hg / HgO electrode was used as the reference electrode, and a platinum wire electrode as the counter electrode. The tests were conducted in a mixed solution of 1M potassium hydroxide and 1M ethanol. The cyclic voltammetry was performed in the potential range of -0.85 to 0.25 V at a scan rate of 50 mV / s. The test results are attached. Figure 8 As shown. Example 1 exhibited the best ethanol catalytic performance, at 3.3 A mg. -1 Pd .
[0056] Accelerated aging tests were conducted on Examples 1-3 above. These tests were performed using a three-electrode system on an electrochemical workstation, with an Hg / HgO electrode as the reference electrode and a platinum wire electrode as the counter electrode. The tests were conducted in a mixed solution of 1M potassium hydroxide and 1M ethanol. The potential range for the accelerated aging tests was -0.85 to 0.25 V, and the scan rate was 100 mV / s. The test results are shown in the attached figure. Figure 9 As shown in Figure a, Examples 1 through 3 all exhibit excellent structural stability. After 5000 cycles, Example 1 retained 54.87% of its catalytic activity, Example 2 retained 27.75% of its catalytic activity, and Example 3 retained 36.87% of its catalytic activity, while commercial Pd / C retained only 19.23% of its catalytic activity after 2500 cycles.
[0057] Chronoamperometry tests were performed on Examples 1-3 above. These tests were conducted using a three-electrode system on an electrochemical workstation, with a Hg / HgO electrode as the reference electrode and a platinum wire electrode as the counter electrode. The tests were performed in a mixed solution of 1M potassium hydroxide and 1M ethanol. The chronoamperometry test potential was -0.25 V. The test results are shown in the attached figure. Figure 9 As shown in Figure b. Example 1 exhibits slow decay of mass activity and superior catalytic durability.
[0058] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.
Claims
1. A method for preparing highly stable Pd-based flexible carbon nanofiber membrane catalysts using femtosecond laser, characterized in that... Steps : (1) Use fresh aqua regia to acid-impregnate the carbon nanofiber membrane. After acid impregnation, remove the carbon nanofiber membrane and vacuum dry it to remove the residual liquid on the surface to obtain the acid-impregnated carbon nanofiber membrane. (2) Disperse PdCl2 in concentrated hydrochloric acid, dilute the solution, and obtain a PdCl2 precursor solution; (3) immersing the carbon nanofiber membrane obtained in step (1) in the PdCl2 precursor solution obtained in step (2), taking out the carbon nanofiber membrane after the immersion, and vacuum drying to remove the liquid remaining on the surface, thereby obtaining a carbon nanofiber membrane loaded with Pd after the pretreatment 2+ ; (4) Using a femtosecond laser to scan the carbon nanofiber membrane loaded with Pd after step (3) pretreatment, obtaining a Pd-based carbon nanofiber membrane catalyst. 2+ (4) Using a femtosecond laser to scan the carbon nanofiber membrane loaded with Pd after step (3) pretreatment, obtaining a Pd-based carbon nanofiber membrane catalyst.
2. The method according to claim 1, characterized in that, Step (1) 1 cm per 4 ~ 6 ml of freshly prepared aqua regia 2 * 0.2 mm (thick) carbon nanofiber membrane, acid dipping 4 ~ 6 h.
3. The method according to claim 1, characterized in that, In step (2), PdCl2 is dispersed in concentrated hydrochloric acid, and the solution is diluted with anhydrous ethanol, deionized water, or a mixture of anhydrous ethanol and deionized water to obtain a PdCl2 precursor solution. The volume ratio of concentrated hydrochloric acid, ethanol and water in the PdCl2 precursor solution is 1:0 ~ 99:0 ~ 99, and the ethanol content is not 0, preferably 1:99:
0. Each 0.1 mmol of PdCl2 is dispersed in 50 ~ 200 µl of concentrated hydrochloric acid.
4. The method according to claim 1, characterized in that, The soaking time in step (3) is 1 to 10 hours, preferably 5 hours.
5. The method according to claim 1, characterized in that, The femtosecond pulsed laser in step (4) has a wavelength of 515 nm, a repetition frequency of 5000 Hz, a pulse width of 100 fs, and a spot size of 0.1 mm.
6. The method according to claim 1, characterized in that, The laser scanning processing scheme in step (4) is set with a laser scanning speed of 250 mm / s, a laser scanning spacing of 0.1 mm, cross scanning, and a laser power of 0.9 ~ 1.5 W.
7. The catalyst prepared according to any one of claims 1-6.
8. The application of the catalyst prepared by the method according to any one of claims 1-6 for the electrocatalytic oxidation of ethanol.