Iron-cluster-regulated nitrogen-doped iron-copper bimetallic atom catalyst as well as preparation method and application of iron-cluster-regulated nitrogen-doped iron-copper bimetallic atom catalyst
The preparation of nitrogen-doped iron-copper bimetallic catalysts with iron cluster regulation by wet chemical reduction method solves the problems of low catalytic efficiency and high preparation cost of existing non-precious metal electrocatalysts, realizes efficient electrocatalytic oxygen reduction reaction, and improves the performance and stability of metal-air batteries.
Patent Information
- Application Number
- CN202511655706.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-12
- Publication Date
- 2026-02-17
AI Technical Summary
Existing non-precious metal electrocatalysts suffer from low catalytic efficiency and high preparation costs in electrocatalytic oxygen reduction reactions. In particular, Fe-NC single-atom catalysts deviate from the ideal value in terms of the adsorption energy of oxygen-containing intermediates, making it difficult to improve their performance.
A wet chemical reduction method was used to prepare a nitrogen-doped iron-copper bimetallic catalyst with iron cluster regulation. Through ZIF-8 synthesis, centrifugal washing, high-temperature calcination, acid washing, and high-temperature calcination, atomically dispersed Fe-Cu bimetallic sites and nano-iron clusters were formed on a nitrogen-doped carbon support, achieving efficient synthesis of the catalyst.
The prepared catalyst has good dispersibility and porous structure, which significantly improves the efficiency of electrocatalytic oxygen reduction reaction, enhances the performance and charge-discharge stability of metal-air battery, and realizes efficient ORR catalysis.
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Figure CN121546077A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of new energy catalytic materials technology, specifically relating to an iron cluster-regulated nitrogen-doped iron-copper bimetallic atom catalyst, its preparation method, and its application. Background Technology
[0002] With the rapid development of novel energy storage and conversion technologies, the development of highly efficient electrocatalysts has become a research hotspot. The electrocatalytic oxygen reduction reaction (ORR), a key step in the cathode reaction of metal-air batteries and fuel cells, suffers from slow kinetics that severely limit energy conversion efficiency. Currently, platinum (Pt)-based catalysts are the mainstream materials in ORR catalysis, but their high cost and resource scarcity greatly restrict their practical application. Therefore, researchers are actively exploring non-precious metal electrocatalysts with excellent catalytic activity and stability to replace platinum group metals (PGMs). This research will not only significantly reduce catalyst costs but also provide important support for the large-scale application of ORR electrocatalysis technology.
[0003] In novel catalyst systems, atomically dispersed transition metal catalysts, especially Fe-NC single-atom catalysts (SACs), have become strong candidates to replace Pt-based catalysts due to their excellent intrinsic ORR catalytic activity. However, these catalysts still face key challenges in practical applications: the adsorption energy of oxygen-containing intermediates (such as *OOH, *O, *OH) at Fe-N sites often deviates from the ideal value, being either too high or too low, which severely restricts further improvement in their performance.
[0004] Currently, improving the ORR performance of Fe-NC SACs mainly focuses on two aspects: increasing the density of exposed active sites and enhancing the intrinsic activity of individual active sites. Regarding optimizing intrinsic activity, common strategies include introducing non-metallic heteroatoms (such as P, S, B, O, Se, Cl, etc.) to precisely regulate the adsorption energy of oxygen-containing intermediates through charge redistribution and metal d-band center modulation. Furthermore, the electronic structure of the host metal active center can be modulated by introducing secondary metal single-atom sites. For example, utilizing the short-range delocalization effect of bimetallic atoms, N / O bridging dd orbital hybridization, or even direct bonding, the host metal site can be effectively activated, significantly reducing the reaction energy barrier of the ORR process. These strategies provide important directions for designing high-performance non-noble metal ORR catalysts.
[0005] Atomic-scale dispersed metal nanoclusters, which regulate bimetallic catalysts, exhibit significant advantages in catalytic performance due to their unique geometric configuration and electronic properties, surpassing single-atom, diatom, and traditional nanoparticle catalysts. The core characteristic of these catalysts lies in the synergistic effect between their metal nanoclusters and bimetallic components: the combination of two different metal elements not only alters the intrinsic properties of the material but also generates new catalytically active sites through interatomic interactions.
[0006] Compared to single-metal clusters, the charge transfer effect is particularly prominent in metal clusters and metal diatomic systems. This charge redistribution phenomenon mainly stems from the differences in electronegativity, work function mismatch, and differences in Fermi levels and electron affinities among metal elements. This change in electronic structure creates locally charged polarized active sites, among which positively charged metal sites are particularly conducive to the adsorption and activation of electron-rich reactants (such as oxygen molecules) and their reaction intermediates, thereby significantly improving catalytic efficiency.
[0007] Gas-phase synthesis and size selection techniques can precisely prepare single-metal, bimetallic, and multimetallic atomic clusters with specific nucleus numbers, but they rely on complex and expensive equipment and have low yields. Atomic layer deposition (ALD) can achieve precise synthesis of single / bimetallic atomic clusters, but its industrial-scale production is limited by the capacity of precision equipment and the high cost of precursors. In contrast, wet chemical reduction methods can prepare cluster materials in batches, but the product size distribution is wide, and it still has significant limitations in the precise synthesis of supported atomic clusters.
[0008] Therefore, developing a technical solution that enables the controllable synthesis of supported metal cluster catalysts and is efficient, precise, and scalable remains a significant challenge. Summary of the Invention
[0009] The purpose of this invention is to provide an iron cluster-controlled nitrogen-doped iron-copper bimetallic atom catalyst, its preparation method, and its application, so as to solve the problems of low catalytic efficiency and high preparation cost of traditional catalyst materials mentioned in the background art.
[0010] To achieve the above objectives, the present invention provides the following technical solution:
[0011] A nitrogen-doped iron-copper bimetallic atom catalyst with iron cluster regulation includes the following steps:
[0012] S1, ZIF-8 Synthesis: Ferrocene, zinc nitrate and dimethylimidazole, iron precursors, were dissolved in methanol solution and stirred to ensure thorough mixing. The mixture was reacted at room temperature for 24 hours. The amounts of ferrocene, zinc nitrate, dimethylimidazole and methanol added were 0.35 g, 1.188 g, 2.625 g and 50 ml, respectively.
[0013] S2, centrifugal washing: Transfer the material prepared in S1 to a centrifuge tube for centrifugal washing, discard the supernatant, add ethanol to the precipitate, mix ultrasonically, and then centrifuge and wash again. Repeat the above washing operation twice. Then, use a vacuum filtration device to perform vacuum filtration, washing, and vacuum filtration repeatedly with anhydrous ethanol. The resulting filter cake is vacuum dried overnight in a vacuum drying oven at 60°C.
[0014] S3. High-temperature calcination: Take the product from S2 into a quartz boat and place it in a vacuum tube furnace for heat treatment. Before heating, the vacuum tube furnace is evacuated and purged with nitrogen three times. The temperature is raised to 950°C within 190 minutes, and then held at 950°C for 2 hours. Finally, it is allowed to cool naturally to room temperature under nitrogen purging conditions.
[0015] S4, Acid washing: The product from S3 was placed in 1 mol / L hydrochloric acid and stirred at 90°C for 24 hours. Then, the filter cake was repeatedly filtered, rinsed and filtered again with distilled water using a vacuum filtration device. The resulting filter cake was vacuum dried overnight at 60°C in a vacuum drying oven to obtain Fe-NC material.
[0016] S5. Evaporation and drying: Place the product from S4 into anhydrous ethanol, then add 3.6 mmol / L copper nitrate ethanol solution, stir at a constant speed to ensure thorough mixing, and react at 90°C for 30 minutes until the ethanol solution is completely evaporated. The amounts of the product from S4, anhydrous ethanol, and copper nitrate ethanol solution added are 20 mg and 15 ml, respectively; the amount of copper nitrate ethanol solution is one of 1 ml, 2 ml, or 4 ml.
[0017] S6. High-temperature calcination: The product from S5 was placed in a quartz boat and subjected to heat treatment in a vacuum tube furnace. Before heating, the vacuum tube furnace underwent three cycles of evacuation and purging with a 5% hydrogen-argon mixture. The temperature was raised to 450°C within 215 minutes, then to 950°C within 100 minutes, and held at 950°C for 2 hours. Finally, it was allowed to cool naturally to room temperature under a 5% hydrogen-argon mixture to obtain FeCu-NC / Fe. AC catalyst.
[0018] Preferably, the reaction in S3 is carried out under nitrogen protection throughout, and the reaction is carried out using a programmed temperature rise method, including a high-temperature reaction stage at 950°C.
[0019] Preferably, the Fe-NC material of S4 must be acid-washed with a 1 mol / L hydrochloric acid solution at 90°C for 24 hours.
[0020] Preferably, the reaction in S6 is carried out under a 5% hydrogen-argon mixture protection condition, and the reaction is carried out using a programmed temperature rise method, including two different temperature reaction stages: 20℃~450℃ and 450℃~950℃.
[0021] The iron-copper bimetallic atomic catalyst comprises a nitrogen-doped carbon support, atomically dispersed Fe-Cu bimetallic sites, and nano-iron clusters.
[0022] The application of iron-copper bimetallic atomic catalysts in electrocatalytic oxygen reduction reactions, and the catalysts are used in the cathode catalyst layer of metal-air batteries or fuel cells.
[0023] Compared with the prior art, the beneficial effects of the present invention are:
[0024] The method for preparing the iron cluster-regulated nitrogen-doped iron-copper bimetallic atomic material of this invention is simple. The resulting porous carbon material has a stable structure, excellent mass transfer, and good dispersibility. The prepared FeCu-NC / FeAC is an excellent electrocatalytic ORR functional catalyst material. Zinc-air batteries (ZABs) assembled based on the FeCu-NC / FeAC catalyst exhibit excellent performance and long charge-discharge cycle stability, achieving highly efficient catalysis of the oxygen reduction reaction (ORR). This can significantly improve the performance indicators of metal-air batteries, promote the development of high-performance energy storage and conversion devices, and provide an innovative technical solution for solving current energy and environmental challenges. Attached Figure Description
[0025] Figure 1 The FeCu-NC / Fe prepared in Example 1 AC Scanning transmission electron microscopy (STEM) image of the aberration-corrected annular dark-field phase of the electrocatalyst;
[0026] Figure 2 The FeCu-NC / Fe prepared in Example 1 AC Elemental mapping diagram of C, N, Cu, and Fe in electrocatalysts;
[0027] Figure 3 The FeCu-NC / Fe prepared in Examples 1 and 3 AC X-ray diffraction pattern of Fe-NC electrocatalyst;
[0028] Figure 4 The FeCu-NC / Fe prepared in Examples 1, 2, and 3 AC Linear voltammetric curves of FeCu-NC and Fe-NC electrocatalysts compared with those of commercial 20wt% Pt / C in oxygen-saturated 0.1M KOH electrolyte;
[0029] Figure 5The FeCu-NC / Fe prepared in Examples 1, 2, and 3 AC H2O2 selectivity and electron transfer number of FeCu-NC, Fe-NC electrocatalysts and corresponding NC substrates in oxygen-saturated 0.1M KOH electrolyte. Detailed Implementation
[0030] 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, and 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.
[0031] refer to Figures 1-5 As shown;
[0032] Example 1:
[0033] A nitrogen-doped iron-copper bimetallic atom catalyst FeCu-NC / Fe with iron cluster regulation AC The preparation method and application of [the substance] include the following steps:
[0034] 0.35 g ferrocene, 1.188 g zinc nitrate, and 2.625 g dimethylimidazole were placed in 50 mL of methanol and stirred at room temperature for 24 h. After centrifugation and washing with ethanol three times, the product was repeatedly filtered and washed with anhydrous ethanol. The resulting precipitate was dried under vacuum at 60 °C overnight. The dried product was subjected to three vacuum-nitrogen cycles in a tube furnace, with the temperature increased to 950 °C at 5 °C / min and held for 2 h, followed by a nitrogen atmosphere reduction to room temperature. The resulting material was stirred at 90 °C for 24 h in 1 mol / L hydrochloric acid, repeatedly filtered and washed with distilled water until neutral, and dried under vacuum at 60 °C to obtain Fe-NC. 20 mg of Fe-NC was then taken. Fe-NC was dispersed in 15 mL of anhydrous ethanol, and 2 mL of 3.6 mmol / L copper nitrate ethanol solution was added. The mixture was stirred and evaporated to dryness at 90 °C. The product was then placed in a tube furnace and subjected to three cycles of vacuum followed by 5% H₂ / Ar purging. The temperature was increased to 450 °C at a rate of 2 °C / min, then increased to 950 °C at a rate of 5 °C / min and held for 2 h. Finally, the mixture was cooled to room temperature in a 5% H₂ / Ar atmosphere, resulting in a stable iron-cluster-controlled nitrogen-doped iron-copper bimetallic atomic material. This sample was named FeCu-NC / Fe AC .
[0035] Take FeCu-NC / Fe ACThe catalyst was prepared by mixing 10 μL of a 20% Nafion solution, 0.5 mL of ethanol, and 0.5 mL of deionized water, and then sonicating for 2 hours to obtain a uniformly dispersed catalyst dispersion. 5 μL of this dispersion was uniformly drop-coated onto the surface of an RDE electrode and allowed to air dry at room temperature. The ORR (Oriented Return Rate) was tested using a three-electrode system. The performance curves are shown below. Figure 4 As shown.
[0036] Figure 1 The FeCu-NC / Fe prepared in Example 1 AC Transmission electron microscopy (TEM) image of the electrocatalyst shows obvious nano-iron clusters on the NC substrate, indicating that the Fe moiety is anchored on the Fe-NC substrate in the form of nano-clusters.
[0037] Figure 2 The FeCu-NC / Fe prepared in Example 1 AC The elemental mapping diagram of C, N, Cu, and Fe in the electrocatalyst shows that C, Fe, and Cu elements are uniformly distributed on the NC substrate.
[0038] Figure 3 Contains the FeCu-NC / Fe prepared in Example 1 AC The X-ray diffraction pattern of the electrocatalyst shows not only diffraction peaks of graphitized carbon but also diffraction peaks of iron species, indicating that Fe aggregates into smaller nanoclusters on the Fe-NC substrate.
[0039] Example 2:
[0040] A method for preparing and applying a nitrogen-doped iron-copper bimetallic atom catalyst FeCu-NC includes the following steps:
[0041] The FeCu-NC / Fe obtained in Example 1 AC The material was stirred in 1 mol / L hydrochloric acid at 90°C for 24 h, repeatedly filtered and washed with distilled water until neutral, and then dried under vacuum at 60°C to finally obtain a stable nitrogen-doped iron-copper bimetallic atomic material, which was named FeCu-NC.
[0042] A uniformly dispersed catalyst dispersion was obtained by mixing 5 mg of FeCu-NC catalyst, 10 μL of 20% Nafion solution, 0.5 mL of ethanol, and 0.5 mL of deionized water, followed by ultrasonic treatment for 2 hours. 5 μL of the catalyst dispersion was then uniformly drop-coated onto the surface of an RDE electrode and allowed to air dry at room temperature. The ORR (Oriented Return Rate) was tested in a three-electrode system, and the performance curve is shown below. Figure 4 As shown.
[0043] Example 3:
[0044] A method for preparing and applying a nitrogen-doped iron metal atom catalyst Fe-NC includes the following steps:
[0045] 0.35 g of ferrocene, 1.188 g of zinc nitrate, and 2.625 g of dimethylimidazole were placed in 50 mL of methanol and stirred at room temperature for 24 h. After centrifugation and washing with ethanol three times, the product was repeatedly filtered and washed with anhydrous ethanol. The resulting precipitate was dried under vacuum at 60 °C overnight. The dried product was subjected to three vacuum-nitrogen cycles in a tube furnace, heated to 950 °C at 5 °C / min and held for 2 h, and then cooled to room temperature under nitrogen atmosphere. The resulting material was stirred at 90 °C for 24 h in 1 mol / L hydrochloric acid, repeatedly filtered and washed with distilled water until neutral, and dried under vacuum at 60 °C. Finally, a stable nitrogen-doped iron atom material was obtained, and the sample was named Fe-NC.
[0046] A uniformly dispersed catalyst dispersion was obtained by mixing 5 mg of Fe-NC catalyst, 10 μL of 20% Nafion solution, 0.5 mL of ethanol, and 0.5 mL of deionized water, and then sonicating for 2 hours. 5 μL of this catalyst dispersion was uniformly drop-coated onto the surface of an RDE electrode and allowed to air dry at room temperature. The ORR (Oriented Return Rate) was tested in a three-electrode system, and the performance curve is shown below. Figure 4 As shown.
[0047] Figure 3 The X-ray diffraction pattern of the Fe-NC electrocatalyst prepared in Example 3 shows that it contains only diffraction peaks of graphitized carbon and no diffraction peaks of iron species, indicating that Fe does not aggregate into small nanoclusters on the NC substrate.
[0048] Figure 4 The FeCu-NC / Fe prepared in Examples 1, 2, and 3 AC Comparing the ORR linear voltammetric curves of FeCu-NC and Fe-NC electrocatalysts with those of a commercial 20wt% Pt / C catalyst in oxygen-saturated 0.1M KOH electrolyte, the graph shows that FeCu-NC / Fe... AC The half-wave potentials of the Fe-NC electrocatalyst were 0.935 V vs. RHE and 0.87 V vs. RHE, respectively, which are close to or higher than the half-wave potential of 0.871 V vs. RHE of the commercial 20 wt% Pt / C catalyst, indicating that the prepared FeCu-NC / Fe AC The electrocatalyst exhibits outstanding 4e-ORR catalytic activity.
[0049] Figure 5 The FeCu-NC / Fe prepared in Examples 1, 2, and 3 ACThe H2O2 selectivity of FeCu-NC, Fe-NC electrocatalysts, and the corresponding NC substrates in oxygen-saturated 0.1M KOH electrolyte is shown in the figure. The figure also shows the H2O2 selectivity of FeCu-NC / Fe... AC The H2O2 selectivity of FeCu-NC and Fe-NC electrocatalysts is in the range of 3-7%, which is much lower than that of the NC substrate (below 50%), indicating that the prepared FeCu-NC / Fe AC The diatomic Fe and Cu sites and iron clusters in FeCu-NC and Fe-NC electrocatalysts have the effect of catalyzing 4e-ORR and exhibit outstanding 4e-ORR selectivity.
[0050] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.
[0051] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for preparing an iron cluster regulated nitrogen-doped iron-copper bimetallic atomic catalyst, characterized in that, It comprises the following steps: S1, ZIF-8 synthesis: iron precursor ferrocene, zinc nitrate and dimethyl imidazole are dissolved in a methanol solution, stirred, fully mixed and uniformly mixed, and reacted at room temperature for 24 hours, wherein the added amounts of the ferrocene, zinc nitrate, 2-methyl imidazole and methanol are 0.35 g, 1.188 g, 2.625 g and 50 ml respectively; S2, centrifugal washing: the material prepared in S1 is transferred to a centrifugal tube for centrifugal washing, the supernatant is discarded, ethanol is added to the precipitate, ultrasonic mixing is performed, then centrifugal washing is performed again, and the above washing operation is repeated twice, then the repeated operation of suction filtration, wetting and suction filtration is performed multiple times with anhydrous ethanol, and the obtained filter cake is vacuum dried in a vacuum drying box at 60°C overnight; S3, high-temperature calcination: the product in S2 is taken in a quartz boat and placed in a vacuum tube furnace for heat treatment, the vacuum tube furnace is subjected to three vacuum pumping and nitrogen charging cycle operations before heating, is heated to 950°C within 190 minutes, is kept at 950°C for 2 hours, and is naturally cooled to room temperature under the condition of nitrogen flow; S4, acid washing: the product in S3 is placed in 1 mol / L hydrochloric acid, stirred at 90°C for 24 hours, then subjected to repeated operation of suction filtration, wetting and suction filtration multiple times with distilled water by using a suction filtration device, and the obtained filter cake is vacuum dried in a vacuum drying box at 60°C overnight to obtain a Fe-N-C material; S5, evaporation drying: the product in S4 is placed in anhydrous ethanol, then 3.6 mmol / L copper nitrate ethanol solution is added, stirred at a constant speed, fully mixed and uniformly mixed, reacted at 90°C for 30 minutes until the ethanol solution is completely evaporated, wherein the added amounts of the product in S4, anhydrous ethanol and copper nitrate ethanol solution are 20 mg, 15 ml and 1 ml, 2 ml or 4 ml respectively; S6, high temperature calcination: take the product in S5 in a quartz boat, place it in a vacuum tube furnace for heat treatment, the vacuum tube furnace is operated three times before heating, vacuum and 5% hydrogen argon mixture circulation, heated to 450°C in 215 minutes, then heated to 950°C in 100 minutes, then kept at 950 degrees Celsius for 2 hours, finally, under the condition of 5% hydrogen argon mixture, natural cooling to room temperature, to obtain FeCu-N-C / Fe AC catalyst.
2. The preparation method of the iron cluster regulated nitrogen-doped iron-copper bimetallic atomic catalyst according to claim 1, characterized in that: The reaction of S3 is performed under nitrogen protection, and the reaction is performed by using a programmed temperature rising method, including a high-temperature reaction stage at 950°C.
3. The preparation method of the iron cluster regulated nitrogen-doped iron-copper bimetallic atomic catalyst according to claim 1, characterized in that: The Fe-N-C material in S4 must be subjected to acid washing with 1 mol / L hydrochloric acid solution at 90°C for 24 hours.
4. The preparation method of the iron cluster regulated nitrogen-doped iron-copper bimetallic atomic catalyst according to claim 1, characterized in that: The reaction of S6 is performed under 5% hydrogen-argon mixed gas protection, and the reaction is performed by using a programmed temperature rising method, including two different temperature reaction stages at 20°C-450°C and 450°C-950°C.
5. The iron-copper bimetallic atomic catalyst prepared according to the preparation method of any one of claims 1-4, characterized in that: The catalyst comprises a nitrogen-doped carbon carrier, atomically dispersed Fe-Cu bimetallic sites and nano iron clusters.
6. Application of the iron-copper bimetallic atomic catalyst in claim 5 in an electrocatalytic oxygen reduction reaction.
7. Use according to claim 6, characterized in that: The catalyst is used for a cathode catalytic layer of a metal-air battery or a fuel cell.