High-performance oxygen reduction reaction electrocatalyst Fe2P-NC as well as preparation method and application thereof
By synthesizing Fe2P-NC catalysts using flash Joule heating technology, the problems of scarce platinum-based catalyst resources and insufficient activity were solved, and a highly efficient and stable oxygen reduction reaction catalyst was prepared, which is suitable for fuel cells.
Patent Information
- Application Number
- CN202511693477.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-02-17
AI Technical Summary
Existing platinum-based oxygen reduction reaction catalysts are scarce and expensive, while heteroatom-doped carbon-based metal catalysts have ORR catalytic activity and long-term durability that cannot meet the actual requirements for long-term, high-efficiency operation.
Fe2P-NC catalysts were synthesized using flash Joule heating technology. By doping heteroatoms and precisely controlling the catalytic activity of the catalyst, uniformly dispersed small-sized nanoparticles were prepared and loaded onto phosphorus-nitrogen co-doped carbon materials to suppress agglomeration and optimize the local coordination environment of the active centers.
The catalyst was prepared efficiently, significantly improving its catalytic activity and stability. It exhibits high half-wave potential and low Tafel slope, with overall performance surpassing that of commercial platinum/carbon catalysts, making it suitable for the fuel cell field.
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Figure CN121546078A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nanocatalytic materials technology, and in particular to a high-performance oxygen reduction reaction electrocatalyst Fe2P-NC, its preparation method, and its application. Background Technology
[0002] Highly efficient and stable oxygen reduction reaction (ORR) catalysts are core materials driving the commercialization of fuel cells and metal-air batteries. Their catalytic performance directly determines the energy conversion efficiency and long-term service stability of the battery.
[0003] Currently, while platinum (Pt)-based catalysts are widely used in this field due to their excellent ORR activity, the inherent drawbacks of scarce and expensive platinum resources significantly increase the cost of battery manufacturing, becoming a core bottleneck restricting their large-scale production and market promotion. To overcome this limitation, heteroatom-doped carbon-based metal catalysts have emerged as one of the most promising research directions for replacing platinum-based catalysts in recent years, thanks to their high abundance on Earth, cost-effectiveness, and the ability to optimize ORR catalytic activity through structural tuning. However, the ORR catalytic activity and long-term durability of currently reported heteroatom-doped carbon-based metal catalysts still fall short of the practical requirements for long-term, high-efficiency operation. Summary of the Invention This invention provides a high-performance oxygen reduction reaction electrocatalyst, its preparation method, and its application, in order to overcome the above-mentioned problems.
[0004] To achieve the above objectives, the technical solution of the present invention is as follows: This invention provides a method for preparing a high-performance oxygen reduction reaction electrocatalyst Fe2P-NC, comprising the following steps: S1: Precursor Synthesis: Weigh iron source and nitrogen source phthalocyanine iron, phosphorus source sodium hypophosphite, carbon black base and dispersing agent as raw materials, and add the raw materials to the solvent in sequence and mix well. After ultrasonic treatment and stirring overnight, a uniformly dispersed black suspension is obtained. After centrifugation and drying, black fine powder is obtained. S2: Synthesis of Fe2P-NC by flash Joule heating method: The black fine powder was ground, then loaded into carbon paper, and then subjected to Joule pyrolysis in a Joule heating device to obtain the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC.
[0005] Furthermore, the dispersing agent is hexadecyltrimethylammonium bromide, and the solvent is ethanol; The mass ratio of the sodium hypophosphite to the hexadecyltrimethylammonium bromide and the carbon black is 1:1:2; The molar ratio of the phthalocyanine iron to the carbon black, calculated as C, is 1:80; The total mass of the mixed raw materials and the solid-liquid ratio of the ethanol are 8.0~9.5:1 (mg:mL).
[0006] Furthermore, the specific conditions for the Joule pyrolysis treatment are as follows: under an inert gas environment, pyrolyze to 1000°C within 0.5 s, and then rapidly cool to below 40°C within 5 s to obtain Fe2P-NC.
[0007] Furthermore, the parameters for the ultrasonic treatment are: power 20kHz, ultrasonic treatment for 0.5 h.
[0008] Furthermore, the drying conditions are: drying at 70°C for 6 hours.
[0009] Furthermore, the flow rate of the inert gas is 50-100 mL / min.
[0010] In another aspect, the present invention provides a high-performance oxygen reduction reaction electrocatalyst Fe2P-NC, which is prepared by the same method described above.
[0011] In another aspect, the present invention provides the application of the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC in the field of fuel cells.
[0012] The beneficial effects of this invention are: (1) The preparation method of a high-performance oxygen reduction reaction electrocatalyst disclosed in this invention realizes the millisecond-level rapid synthesis of Fe2P-NC high-efficiency ORR electrocatalyst based on flash Joule heating technology. During the ultrafast Joule heating process of 500 ms, the catalytic activity of the catalyst is precisely controlled by heteroatom engineering, which significantly shortens the preparation cycle. The method is simple to operate and easy to scale up. (2) The ORR electrocatalyst prepared by this method, the Fe2P phase electrocatalyst supported on phosphorus-nitrogen co-doped carbon material, exhibits a uniformly dispersed small-sized nanoparticle morphology with no obvious agglomeration. Figure 2 This superior microstructure benefits from the inhibitory effect of the ultrafast thermal shock process of FJH technology on the aggregation of metal particles. The introduction of phosphorus not only reduces the loss of nitrogen during pyrolysis, but also optimizes the local coordination environment of the active center, precisely controls the adsorption intensity of oxygen-containing intermediates, and accelerates the reaction kinetics. (3) The prepared Fe2P-NC catalyst has an average size of approximately 9.7 nm and is uniformly anchored on an N, P co-doped carbon framework (Bet surface area = 616.4529 m). 2 g -1With its high specific surface area and abundant pore structure, it has more space for active site exposure and better mass transfer and storage capabilities, which helps to improve catalytic efficiency. Moreover, it can exhibit a high half-wave potential and a low Tafel slope in alkaline electrolyte systems. Its comprehensive catalytic performance has surpassed that of commercial platinum / carbon (Pt / C) catalysts. (4) Through the synergistic effect of heteroatom doping engineering and advanced flash heating technology, this invention provides a new path for the efficient preparation of heteroatom-doped carbon-based metal catalysts, and successfully prepares ORR catalysts with high catalytic activity, excellent cost-effectiveness and ultrafast synthesis characteristics, providing a practical technical solution for the industrial application of non-precious metal carbon-based ORR catalysts. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0014] Figure 1 The flowchart shows the synthesis scheme of the Fe2P-NC catalyst. Figure 2 Image of Fe2P-NC catalyst using scanning electron microscopy (SEM); Figure 3 Here is a BET (Body Surface Area) image of the catalyst, where Figure 3 Image a shows the specific surface area (BET) of the Fe2P-NC catalyst. Figure 3 b is the specific surface area (BET) image of the Fe-NC catalyst; Figure 4 The graph shows the comparison results of linear sweep voltammetry (LSV) tests of Fe2P-NC catalyst in O2-saturated 0.1M KOH solution; Figure 5 The figure shows the test results of the stability and methanol poisoning resistance of the Fe2P-NC catalyst. Figure 5 a represents the stability test results of the Fe2P-NC catalyst. Figure 5 b represents the test results for resistance to methanol poisoning. Detailed Implementation
[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0016] The principle involved in this invention: In the study of heteroatom-doped carbon-based catalysts, phosphorus (P), as a typical doping element, possesses unique regulatory advantages: on the one hand, in the molecular structure of iron phthalocyanine (FePc), Fe... 2+ It forms a stable planar Fe-N4 coordination structure with the four N atoms of the phthalocyanine ring, while sodium hypophosphite, as a strong reducing phosphorus source, decomposes during high-temperature heat treatment to produce active phosphorus species (such as P). 0 Phosphorus compounds (such as PH3) exhibit strong reactivity and preferentially bind to Fe in the Fe-N4 coordination structure, breaking the original Fe-N coordination bond. As the reaction proceeds, Fe further reacts with excess active phosphorus species, gradually forming Fe-P bonds and eventually agglomerating into the FeP2 crystalline phase. On the other hand, introducing phosphorus into the carbon material framework not only optimizes the electron transport properties of the carbon matrix but also enhances the material's adsorption affinity for oxygen (O2) through the electronegativity and electronic structure of phosphorus atoms. This significantly improves the kinetic efficiency of the electrocatalytic reaction, providing crucial support for optimizing ORR catalytic performance.
[0017] Flash Joule heating (FJH) technology has gained widespread recognition as a general strategy for synthesizing carbon nanomaterials. Its core advantage lies in its ability to effectively suppress the escape of external nitrogen species from carbon materials even at high heating temperatures, providing crucial technical support for the stable doping of heteroatoms (such as N and P in this scheme). In this invention, millisecond-level rapid synthesis of a highly efficient Fe2P-NC ORR electrocatalyst was achieved based on FJH technology. During the 500 ms ultrafast Joule heating process, the catalytic activity of the catalyst was precisely controlled through heteroatom doping. The prepared Fe2P-NC catalyst has an average size of approximately 9.7 nm and is uniformly anchored on an N, P co-doped carbon framework (Bet surface area = 616.4529 m). 2 g -1Exhibiting a high half-wave potential and a low Tafel slope in alkaline electrolyte systems, its overall catalytic performance surpasses that of commercial platinum / carbon (Pt / C) catalysts. This invention provides a new pathway for the efficient preparation of heteroatom-doped carbon-based metal catalysts through the synergistic effect of heteroatom doping engineering and advanced flash heating technology.
[0018] Example: A method for preparing a high-performance oxygen reduction reaction electrocatalyst Fe2P-NC includes the following steps: S1, Precursor Synthesis: S11, 0.1 mmol ferrophthalocyanine (FePc), 50 mg sodium hypophosphite (NaH2PO2), 50 mg cetyltrimethylammonium bromide (C 19 H 42 BrN and 100 mg of carbon black were each dispersed in 30 ml of ethanol solution; S12. The obtained solution was sonicated for 0.5 h at a frequency of 20 kHz and then stirred overnight to obtain a uniformly dispersed black suspension. S13. After centrifuging the suspension, place it in an oven at 70°C and dry for 6 hours. Then collect the dried black fine powder.
[0019] S2, Synthesis of Fe2P-NC by flash evaporation and Joule heating (FJH) method: S21. After thoroughly grinding the collected black fine powder (grinding manually in a mortar for 3 minutes), put it into carbon paper for the next pyrolysis treatment. S22. Under an Ar atmosphere, the catalyst was pyrolyzed to 1000℃ within 0.5 s using a Joule heating device and then rapidly cooled to below 40℃ within 5 s to obtain the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC. The synthesis process of the Fe2P-NC catalyst is as follows: Figure 1 As shown.
[0020] The morphology of the prepared Fe2P-NC catalyst was characterized using scanning electron microscopy (SEM). The SEM images of the Fe2P-NC catalyst are shown below. Figure 2 As shown, from Figure 2 It can be seen that the uniformly dispersed Fe2P nanocrystals are anchored on the PN co-doped carbon support, forming a three-dimensional porous structure with spatial pores. The Fe2P phase electrocatalyst loaded on the phosphorus-nitrogen co-doped carbon material exhibits a uniformly dispersed small-sized nanoparticle morphology without obvious agglomeration.
[0021] The prepared Fe2P-NC catalyst was subjected to nitrogen adsorption-desorption tests, and compared with the Fe-NC catalyst without P doping. The specific surface area (BET) image is shown below. Figure 3 As shown, from Figure 3 a and Figure 3 b shows that the BET specific surface area of Fe2P-NC is 616.4 m². 2 / g, total pore volume is 2.7 cm³. 3 / g, far exceeding the BET specific surface area of 574.2 m² for Fe-NC. 2 / g, indicating that the Fe2P-NC catalyst doped with P in this scheme has more space for active site exposure and better mass transfer and storage capacity, thereby optimizing the mass transfer process between electrolyte and oxygen and helping to improve the catalytic efficiency of the catalyst.
[0022] Performance testing 1. Linear sweep voltammetry test (1) Test method: The performance of the Fe2P-NC catalyst was measured using a CHI 760E electrochemical workstation in a standard three-electrode glass cell setup, with Fe-NC catalyst and commercial Pt / C catalysts as comparisons. The test used an Hg / HgO electrode as the reference electrode, a graphite rod as the counter electrode, and a rotating disk electrode (5 mm in diameter) with catalyst as the working electrode. 4 mg of catalyst was dispersed in 960 μL of ethanol and 40 μL of 5 wt% Nafion solution and sonicated for 30 min to form a uniform catalyst ink. Then, 5 μL of the catalyst ink was dropped onto the glassy carbon electrode using a microgun and allowed to air dry at room temperature. The electrolyte was washed with 0.1 M KOH solution with O2 for 30 min to ensure O2 saturation before measurement. Before linear sweep voltammetry (LSV) testing, a 50 mV·s⁻¹ method was used. -1 Cyclic voltammetry (CV) scans were performed continuously at a scan rate from 1.1 to 0.2 V relative to the RHE (reference electrode) until the curve stabilized. The scan rate was 10 mV·s at a rotation speed of 1600 rpm. -1 Record the ORR polarization curve. Measure the current density (J) and the confined diffusion current density (J). L It conforms to the Koutecký-Levich (KL) equation.
[0023] (2) Test results All potentials of the reversible hydrogen electrode: E(RHE) = E(Hg / HgO) + 0.098 + 0.059 pH, where E(RHE) represents the potential relative to the reversible hydrogen electrode and E(Hg / HgO) represents the potential relative to the Hg / HgO electrode. Linear sweep voltammetry (LSV) of Fe2P-NC catalyst in O2-saturated 0.1M KOH solution, for example... Figure 4As shown, Fe2P-NC exhibits excellent catalytic activity. Compared to RHE, the half-wave potential (E0) of Fe2P-NC is significantly lower. 1 / 2 The limiting current density of Fe2P-NC reaches 0.85V, a positive shift of 30 mV compared to Pt / C (0.82 V); L The value is 6.01 mA·cm. -2 It is superior to Pt / C (5.67 mA·cm⁻¹). -2 Compared to Fe-NC, Fe2P-NC exhibits significantly enhanced redox activity, with its E... 1 / 2 (0.64 V higher than RHE) and J L (5.05 mA·cm) -2 )higher.
[0024] 2. Catalyst stability and resistance to methanol poisoning tests (1) Catalyst stability test: To test the durability of Fe2P-NC, linear sweep voltammetry was used in 0.1 M KOH electrolyte. The scan range was set to 0.05–1.1 V (vs. RHE), and the scan rate was 100 mV•s. -1 After a total of 5000 iterations, the results are as follows: Figure 5 As shown in figure a, after 5000 CV cycles, the E of Fe2P-NC 1 / 2 and J L All remained at their initial levels, with no significant degradation observed, indicating that Fe2P-NC exhibits excellent ORR catalytic stability.
[0025] (2) Test of catalyst resistance to methanol poisoning: To test the methanol poisoning resistance of Fe2P-NC, a linear sweep voltammetry method was used in 0.1 M KOH electrolyte. The scan range was set to 0.05–1.1 V (vs. RHE), and the scan rate was 10 mV•s. -1 1600 r•min -1 A certain amount of methanol was injected into the electrolyte, and the ORR polarization curve of Fe2P-NC was tested and compared with that before methanol injection. The results are as follows: Figure 5 As shown in b, the catalytic activity of Fe2P-NC after methanol injection (half-wave potential (E)) 1 / 2 Only a negative displacement of 5 mV occurred. This result confirms that the Fe2P-NC catalyst prepared in this invention has excellent methanol tolerance. This characteristic can effectively alleviate the cross-interference of methanol between electrodes, laying an important foundation for its application in the cathode catalysis of PEMFC (proton exchange membrane fuel cell) and highlighting its great application potential. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a high-performance oxygen reduction reaction electrocatalyst Fe2P-NC, characterized in that, Includes the following steps: S1: Precursor Synthesis: Weigh iron source and nitrogen source phthalocyanine iron, phosphorus source sodium hypophosphite, carbon black base and dispersing agent as raw materials, and add the raw materials to the solvent in sequence and mix well. After ultrasonic treatment and stirring overnight, a uniformly dispersed black suspension is obtained. After centrifugation and drying, a black fine powder is obtained. S2: Synthesis of Fe2P-NC by flash Joule heating method: The black fine powder was ground, then loaded into carbon paper, and then subjected to Joule pyrolysis in a Joule heating device to obtain the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC.
2. The method for preparing the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC according to claim 1, characterized in that, The dispersant is hexadecyltrimethylammonium bromide, and the solvent is ethanol; The mass ratio of the sodium hypophosphite to the hexadecyltrimethylammonium bromide and the carbon black is 1:1:2; The molar ratio of the phthalocyanine iron to the carbon black, calculated as C, is 1:80; The total mass of the mixed raw materials and the solid-liquid ratio of the ethanol are 8.0~9.5:1 (mg:mL).
3. The method for preparing the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC according to claim 1, characterized in that, The specific conditions for the Joule pyrolysis treatment are as follows: under an inert gas environment, pyrolyze to 1000°C within 0.5 s, and then rapidly cool to below 40°C within 5 s to obtain Fe2P-NC.
4. The method for preparing the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC according to claim 1, characterized in that, The parameters for the ultrasonic treatment are: power 20kHz, ultrasonic treatment for 0.5 h.
5. The method for preparing the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC according to claim 1, characterized in that, The drying conditions are: drying at 70°C for 6 hours.
6. The method for preparing the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC according to claim 3, characterized in that, The flow rate of the inert gas is 50-100 mL / min.
7. A high-performance oxygen reduction reaction electrocatalyst Fe2P-NC, characterized in that, It was prepared by the method described in claim 1 for preparing the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC.
8. The application of the high-performance oxygen reduction reaction electrocatalyst Fe2P-NC as described in claim 7 in the field of fuel cells.