Iron-gallium bimetal oxygen reduction catalyst as well as preparation method and application thereof
By doping gallium atoms into the Fe-NC catalyst, a FeGa-NC catalyst was constructed, which solved the problems of insufficient activity and poor stability of Fe-NC, and achieved efficient operation and improved stability of zinc-air batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIAONING UNIVERSITY
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-01
AI Technical Summary
The insufficient oxygen reduction reaction activity and poor stability of existing Fe-NC-based materials limit the widespread application of zinc-air batteries.
By doping gallium atoms into Fe-based nitrogen-doped carbon, an iron-gallium bimetallic oxygen reduction catalyst (FeGa-NC) was constructed. Abundant bimetallic active centers were built on the nitrogen-doped carbon matrix using wet milling and stepwise calcination methods to enhance the electron transfer effect.
It significantly improves the oxygen reduction performance and stability of the catalyst, outperforming commercial Pt/C catalysts, and has good resistance to methanol interference, enabling efficient operation of zinc-air batteries.
Smart Images
Figure CN121964683A_ABST
Abstract
Description
A bimetallic iron-gallium oxygen reduction catalyst, its preparation method and application Technical Field
[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to an iron-gallium bimetallic oxygen reduction catalyst, its preparation method, and its application. Background Technology
[0002] Zinc-air batteries, with their significant cost advantages, excellent environmental friendliness, and theoretical energy density, have become one of the most promising research directions in the field of energy storage technology. However, the slow kinetics of the oxygen reduction reaction (ORR) at the cathode severely limit their large-scale application. Since the most efficient noble metal platinum-based materials currently available are expensive and lack stability, developing efficient, low-cost, abundant, and high-performance non-noble metal-based ORR electrocatalysts is key to promoting the widespread application of zinc-air batteries.
[0003] Among numerous candidate materials, metal-nitrogen-doped carbon (M-NC) catalysts have shown broad application prospects due to their excellent ORR activity, abundant reserves, and low cost. For M-NC catalysts constructed with different metal centers, Fe-NC-based materials exhibit superior ORR performance and excellent electrical conductivity, making them the preferred choice among current non-noble metal ORR catalysts. However, the activity of existing Fe-NC catalysts has not yet fully reached theoretical performance, and their practical applications are still limited by insufficient activity and poor stability. To address these issues, researchers have proposed a design strategy of doping Fe-based nitrogen-doped carbon with a second metal atom. Due to the strong pd orbital hybridization between p-block (such as In, Ga, Sn, etc.) and d-block metal atoms, electron delocalization can be induced and reduced... The energy barrier of OH protonation further modulates the electronic structure of the central metal, thereby promoting the improvement of ORR activity. Based on this, the present invention designs an iron-gallium bimetallic oxygen reduction catalyst. Summary of the Invention
[0004] To address the problem of slow oxygen reduction kinetics at the cathodes of fuel cells and metal-air batteries, one objective of this invention is to provide an iron-gallium bimetallic oxygen reduction catalyst and its preparation method.
[0005] This invention is achieved through the following technical solution: an iron-gallium bimetallic oxygen reduction catalyst, which is an iron-gallium bimetallic oxygen reduction catalyst (FeGa-NC) with abundant bimetallic active centers prepared based on a nitrogen-doped carbon matrix; the preparation method includes the following steps: 1) dissolving 2-methylimidazolium and zinc salt in an organic solvent and mixing them, stirring at room temperature, centrifuging, washing, and vacuum drying to obtain ZIF-8; 2) placing the ZIF-8 obtained in step 1) in a tube furnace and pyrolyzing it in an inert gas atmosphere to obtain nitrogen-doped carbon material (NC); 3) mixing and grinding the nitrogen-doped carbon material (NC) obtained in step 2) with iron salt and gallium salt in deionized water to obtain a mixture.
[0006] 4) The mixture obtained in step 3) is placed in a tube furnace and pyrolyzed in an inert gas atmosphere to obtain an iron-gallium bimetallic oxygen reduction catalyst (FeGa-NC).
[0007] Further, in step 1), the zinc salt is selected from one or more of zinc acetylacetonate, zinc acetate, zinc citrate, zinc nitrate, zinc carbonate, zinc sulfate, and zinc chloride and their hydrates; the organic solvent is selected from one of methanol, ethanol, isopropanol, and acetone.
[0008] Further, in step 1), the stirring at room temperature lasts for 12-24 hours; the vacuum drying lasts for 12-24 hours at a temperature of 40°C-90°C.
[0009] Further, in step 2), the pyrolysis is performed at a temperature of 800℃-1000℃ for a time of 2h-4h.
[0010] Further, in step 3), the iron salt is selected from one or more of ferric acetylacetone, ferric acetate, ferric citrate, ferric nitrate, ferric carbonate, ferric sulfate, and ferric chloride and their hydrates; the gallium salt is selected from one or more of gallium acetylacetone, gallium acetate, gallium citrate, gallium nitrate, gallium carbonate, gallium sulfate, and gallium chloride and their hydrates.
[0011] Further, in step 3), the total molar amount of iron salt and gallium salt added to each 20 mg of nitrogen-doped carbon material (NC) is 0.015 mmol to 0.020 mmol, with a molar ratio of iron salt to gallium salt of (1-3):1.
[0012] Further, in step 4), the pyrolysis is performed at a temperature of 800℃-1000℃ for a time of 2h-4h.
[0013] Furthermore, in steps 2) and 4), the inert gas is nitrogen or argon.
[0014] The second objective of this invention is to provide an application of an iron-gallium bimetallic oxygen reduction catalyst in the oxygen reduction reaction at the cathode of a zinc-air battery.
[0015] Further, the method is as follows: a zinc-air battery is constructed in an alkaline electrolyte solution, using carbon cloth coated with an iron-gallium bimetallic oxygen reduction catalyst (FeGa-NC) as the air cathode and zinc foil as the anode. The alkaline electrolyte solution is a 5M-7M KOH solution containing 0.1M-0.3M Zn(OAc)₂.
[0016] The beneficial effects of this invention are: 1. This invention utilizes wet milling and stepwise calcination strategies, and leverages the synergistic effect of bimetallic Fe / Ga to enhance the electron transfer effect of FeN4 active centers, successfully constructing FeGa-NC catalytic materials containing abundant bimetallic active centers on a nitrogen-doped carbon matrix.
[0017] 2. In this invention, FeGa-NC exhibits excellent ORR performance under alkaline conditions. Its catalytic activity and kinetic parameters are significantly better than those of Pt / C catalysts, while also possessing excellent stability and resistance to methanol interference.
[0018] 3. The test results of the FeGa-NC catalyst prepared in this invention in a zinc-air battery further verify its feasibility as a substitute for noble metal catalysts. Attached Figure Description
[0019] Figure 1 is a SEM image of Fe2Ga1-NC prepared in Example 2.
[0020] Figure 2 is a TEM image of Fe2Ga1-NC prepared in Example 2.
[0021] Figure 3 shows the elemental mapping of Fe2Ga1-NC prepared in Example 2; where (a) is the SEM mapping of the Fe2Ga1-NC catalyst; (b) is the elemental distribution of Fe; (c) is the elemental distribution of Ga; (d) is the elemental distribution of C; (e) is the elemental distribution of N; and (f) is the elemental distribution of O.
[0022] Figure 4 shows the XRD patterns of NC, FeGa-NC prepared in Examples 1-3, Fe-NC prepared in Comparative Example 1, and Ga-NC prepared in Comparative Example 2.
[0023] Figure 5 is a comparison of the LSV of FeGa-NC prepared in Examples 1-3, Fe-NC prepared in Comparative Example 1, Ga-NC prepared in Comparative Example 2, and commercial Pt / C in 0.1M KOH.
[0024] Figure 6 shows the LSV diagrams of Fe2Ga1-NC and commercial Pt / C prepared in Example 2 after 10k cycles in 0.1M KOH.
[0025] Figure 7 shows the open-circuit voltage (a) and discharge power density (b) curves of Fe2Ga1-NC prepared in Example 2 in a zinc-air battery.
[0026] Figure 8 shows the cyclic charge-discharge curves of Fe2Ga1-NC prepared in Example 2 in a zinc-air battery. Detailed Implementation
[0027] Example 1: Iron-gallium bimetallic oxygen reduction catalyst (Fe1Ga1-NC)
[0028] The preparation method is as follows: 1. Preparation of zeolite imidazole ester skeleton material-8 (ZIF-8): Dissolve 10.52g of 2-methylimidazolium in 100mL of methanol to obtain solution A.
[0029] Dissolve 4.78g of zinc nitrate hexahydrate in 100mL of methanol to obtain solution B.
[0030] Solution A was poured into solution B and mixed rapidly, then stirred vigorously at room temperature for 24 hours. The white precipitate was collected by centrifugation, washed three times with methanol, and dried under vacuum at 70°C overnight to obtain ZIF-8 white powder.
[0031] 2. Synthesis of nitrogen-doped carbon material (NC): ZIF-8 powder was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, it was pyrolyzed at 900℃ for 2 hours to obtain nitrogen-doped carbon material (NC).
[0032] 3. Mixing: Dissolve ferric nitrate nonahydrate (3.2 mg, 0.008 mmol) and gallium nitrate nonahydrate (2.0 mg, 0.008 mmol) thoroughly in 100 μL of deionized water, add 20 mg of NC material, mix and grind until a particle-free dry powder is formed to obtain the mixture.
[0033] 4. Synthesis of Fe1Ga1-NC: The mixture was placed in a quartz boat, then in a tube furnace, and pyrolyzed at 900℃ for 2 hours under an argon atmosphere, with argon gas continuously flowing through. After natural cooling, Fe was obtained. 3+ and Ga 3+ The FeGa-NC catalyst with a molar ratio of 1:1 is labeled as Fe1Ga1-NC.
[0034] Example 2: Iron-gallium bimetallic oxygen reduction catalyst (Fe2Ga1-NC)
[0035] The preparation method is as follows: 1. Preparation of zeolite imidazole ester skeleton material-8 (ZIF-8): Same as in Example 1.
[0036] 2. Synthesis of nitrogen-doped carbon (NC) materials: Same as in Example 1.
[0037] 3. Mixing: Dissolve ferric nitrate nonahydrate (4.4 mg, 0.011 mmol) and gallium nitrate nonahydrate (1.3 mg, 0.005 mmol) thoroughly in 100 μL of deionized water, add 20 mg of NC material, mix and grind until a particle-free dry powder is formed to obtain the mixture.
[0038] 4. Synthesis of Fe2Ga1-NC: The mixture was placed in a quartz boat, then in a tube furnace, and pyrolyzed at 900℃ for 2 hours under an argon atmosphere, with argon gas continuously flowing through. After natural cooling, Fe was obtained. 3+ and Ga 3+ The FeGa-NC catalyst with a molar ratio of 2:1 is labeled as Fe2Ga1-NC.
[0039] Example 3: Iron-gallium bimetallic oxygen reduction catalyst (Fe3Ga1-NC)
[0040] The preparation method is as follows: 1. Preparation of zeolite imidazole ester skeleton material-8 (ZIF-8): Same as in Example 1.
[0041] 2. Synthesis of nitrogen-doped carbon (NC) materials: Same as in Example 1.
[0042] 3. Mixing: Dissolve ferric nitrate nonahydrate (4.8 mg, 0.012 mmol) and gallium nitrate nonahydrate (1.0 mg, 0.004 mmol) thoroughly in 100 μL of deionized water, add 20 mg of NC material and mix and grind until a particle-free dry powder is formed to obtain the mixture.
[0043] 4. Synthesis of Fe3Ga1-NC: The mixture was placed in a quartz boat, then in a tube furnace, and pyrolyzed at 900℃ for 2 hours under an argon atmosphere, with argon gas continuously flowing through. After natural cooling, Fe was obtained. 3+ and Ga 3+ The FeGa-NC catalyst with a molar ratio of 3:1 is labeled as Fe3Ga1-NC.
[0044] Comparative Example 1: Iron monometallic oxygen reduction catalyst (Fe-NC)
[0045] The preparation method is as follows: 1. Preparation of zeolite imidazole ester skeleton material-8 (ZIF-8): Same as in Example 1.
[0046] 2. Synthesis of nitrogen-doped carbon (NC) materials: Same as in Example 1.
[0047] 3. Synthesis of Fe-NC: 6.5 mg of ferric nitrate nonahydrate (0.016 mmol) was fully dissolved in 100 μL of deionized water, 20 mg of NC material was added, and the mixture was ground until a dry powder without particles was formed, thus obtaining a mixture.
[0048] The mixture was placed in a quartz boat and then in a tube furnace. Under an argon atmosphere, it was pyrolyzed at 900°C for 2 hours with argon gas flowing through it. After natural cooling, the Fe-NC catalyst was obtained.
[0049] Comparative Example 2: Gallium monometallic oxygen reduction catalyst (Ga-NC)
[0050] The preparation method is as follows: 1. Preparation of zeolite imidazole ester skeleton material-8 (ZIF-8): Same as in Example 1.
[0051] 2. Synthesis of nitrogen-doped carbon (NC) materials: Same as in Example 1.
[0052] 3. Synthesis of Ga-NC: Gallium nitrate nonahydrate (4.1 mg, 0.016 mmol) was fully dissolved in 100 μL of deionized water, 20 mg of NC material was added, and the mixture was ground until a particle-free dry powder was formed to obtain the mixture.
[0053] The mixture was placed in a quartz boat and then in a tube furnace. Under an argon atmosphere, it was pyrolyzed at 900°C for 2 hours with argon gas flowing through it. After natural cooling, the Ga-NC catalyst was obtained.
[0054] Example 4 Performance Experiment
[0055] I. Microstructure of Iron-Gallium Bimetallic Oxygen Reduction Catalysts
[0056] The Fe2Ga1-NC prepared in Example 2 was subjected to scanning electron microscopy (SEM), transmission electron microscopy (TEM), and elemental mapping tests.
[0057] Figure 1 shows the SEM image of Fe2Ga1-NC prepared in Example 2. Obvious metal particles can be observed on the surface of the dodecahedron, and the metal particles are uniformly dispersed with an average particle size of 200 nm.
[0058] Figure 2 is a TEM image of the Fe2Ga1-NC prepared in Example 2, which confirms that there are uniformly distributed metal particles with uniform particle size on the surface of the Fe2Ga1-NC catalyst.
[0059] Figure 3 is an elemental mapping diagram of Fe2Ga1-NC prepared in Example 2, showing that Ga, Fe, C, N and O elements are uniformly distributed throughout the material.
[0060] II. Compositional Analysis of Iron-Gallium Bimetallic Oxygen Reduction Catalyst
[0061] X-ray diffraction (XRD) tests were performed on the prepared NC materials, FeGa-NC prepared in Examples 1-3, Fe-NC prepared in Comparative Example 1, and Ga-NC prepared in Comparative Example 2, as shown in Figure 4. Figure 4 shows that after high-temperature carbonization, the Fe3Ga1-NC, Fe2Ga1-NC, and Fe1Ga1-NC catalysts all exhibit two graphitic carbon diffraction peaks on the NC substrate. Furthermore, the other diffraction peaks of these three catalysts match the characteristic diffraction peaks of FeGa2O4, indicating that the metal particles present on the surface of the FeGa-NC catalyst are FeGa2O4, and also proving that Fe... 3+ and Ga 3+ It was successfully doped onto a nitrogen-doped carbon matrix.
[0062] III. Electrochemical Testing of Iron-Gallium Bimetallic Oxygen Reduction Catalysts
[0063] Methods: The oxygen reduction performance of FeGa-NC prepared in Examples 1-3, Fe-NC prepared in Comparative Example 1, Ga-NC prepared in Comparative Example 2, and commercial Pt / C were tested in a three-electrode system. The test procedure is as follows: an electrode coated with catalyst ink was used as the working electrode, silver chloride as the reference electrode, and a graphite rod as the counter electrode. The test was conducted using a CHI760E electrochemical workstation. Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were performed on the catalyst in oxygen-saturated 0.1M KOH solution at room temperature. See Figures 5 and 6.
[0064] Figure 5 shows a comparison of the LSV of FeGa-NC prepared in Examples 1-3, Fe-NC prepared in Comparative Example 1, Ga-NC prepared in Comparative Example 2, and commercial Pt / C in 0.1M KOH. Among catalysts with different molar ratios, Fe2Ga1-NC (E 1 / 2 =0.91V; J L =7.21mA cm -2 Fe2Ga1-NC exhibits the best performance, while also outperforming the control catalysts Fe-NC, Ga-NC, and commercial Pt / C (E) 1 / 2 =0.83V; J L =6.35mA cm -2 This indicates that it has good ORR activity under alkaline conditions.
[0065] Figure 6 shows the LSV curves of Fe2Ga1-NC prepared in Example 2 and commercial Pt / C after 10k CV cycles. In 0.1 MkOH solution, the half-wave potential of Fe2Ga1-NC decreased by 6 mV, while that of commercial Pt / C decreased by 11 mV, indicating that the Fe2Ga1-NC catalyst has higher electrochemical stability.
[0066] Example 5: Application of iron-gallium bimetallic oxygen reduction catalyst in zinc-air batteries
[0067] Methods: The Fe2Ga1-NC catalyst prepared in Example 2 was used to test the performance of a zinc-air battery. The testing procedure is as follows: A zinc-air battery was prepared using zinc foil as the anode and composite carbon cloth loaded with Fe2Ga1-NC catalyst as the air cathode. The electrolyte solution was 6M KOH (containing 0.2M Zn(OAc)2). The open-circuit voltage of the battery was measured using an electrochemical workstation (IT). The discharge curve of the zinc-air battery was measured using an LSV (Laser-Sensitive Voltage) test. The cycle charge-discharge curve of the zinc-air battery was measured using a CP (Cyclic-Physical Cyclic) test. See Figures 7 and 8.
[0068] Figure 7 shows the open-circuit voltage (a) and discharge power density (b) curves of the Fe2Ga1-NC prepared in Example 2 in a zinc-air battery. The zinc-air battery based on Fe2Ga1-NC exhibits an open-circuit voltage as high as 1.43V and a peak power density of 125.1 mW / cm². -2 It surpasses the Pt / C catalyst-based battery (107.5 mW cm⁻¹). -2 It exhibits good performance.
[0069] Figure 8 shows the cyclic charge-discharge curves of the Fe2Ga1-NC prepared in Example 2 in a zinc-air battery. The Fe2Ga1-NC battery maintained excellent stability after 70 hours of cyclic charge-discharge testing.
Claims
1. An iron-gallium bimetallic oxygen reduction catalyst, characterized in that, The iron-gallium bimetallic oxygen reduction catalyst is a bimetallic active center FeGa-NC catalyst prepared based on a nitrogen-doped carbon matrix. The preparation method includes the following steps: 1) Dissolving 2-methylimidazolium and zinc salt in an organic solvent and mixing them, stirring at room temperature, centrifuging, washing, and vacuum drying to obtain ZIF-8; 2) Placing the ZIF-8 obtained in step 1) in a tube furnace and pyrolyzing it in an inert gas atmosphere to obtain nitrogen-doped carbon material NC; 3) Mixing and grinding the nitrogen-doped carbon material NC obtained in step 2) with iron salt and gallium salt in deionized water to obtain a mixture; 4) Placing the mixture obtained in step 3) in a tube furnace and pyrolyzing it in an inert gas atmosphere to obtain the iron-gallium bimetallic oxygen reduction catalyst FeGa-NC.
2. The iron-gallium bimetallic oxygen reduction catalyst according to claim 1, characterized in that, In step 1), the zinc salt is selected from one or more of zinc acetylacetonate, zinc acetate, zinc citrate, zinc nitrate, zinc carbonate, zinc sulfate, and zinc chloride and their hydrates; the organic solvent is selected from one of methanol, ethanol, isopropanol, and acetone.
3. The iron-gallium bimetallic oxygen reduction catalyst according to claim 1, characterized in that, In step 1), the stirring is carried out at room temperature for 12-24 hours; the vacuum drying is carried out at a temperature of 40°C-90°C for 12-24 hours.
4. The iron-gallium bimetallic oxygen reduction catalyst according to claim 1, characterized in that, In step 2), the pyrolysis is performed at a temperature of 800℃-1000℃ for a time of 2h-4h.
5. The iron-gallium bimetallic oxygen reduction catalyst according to claim 1, characterized in that, In step 3), the iron salt is selected from one or more of ferric acetylacetone, ferric acetate, ferric citrate, ferric nitrate, ferric carbonate, ferric sulfate, and ferric chloride and their hydrates; the gallium salt is selected from one or more of gallium acetylacetone, gallium acetate, gallium citrate, gallium nitrate, gallium carbonate, gallium sulfate, and gallium chloride and their hydrates.
6. The iron-gallium bimetallic oxygen reduction catalyst according to claim 1, characterized in that, In step 3), the total molar amount of iron salt and gallium salt added to each 20 mg of nitrogen-doped carbon material NC is 0.015 mmol to 0.020 mmol; the molar ratio of iron salt to gallium salt is (1-3):
1.
7. The iron-gallium bimetallic oxygen reduction catalyst according to claim 1, characterized in that, In step 4), the pyrolysis is performed at a temperature of 800℃-1000℃ for a time of 2h-4h.
8. The iron-gallium bimetallic oxygen reduction catalyst according to claim 1, characterized in that, In steps 2) and 4), the inert gas is nitrogen or argon.
9. The application of the iron-gallium bimetallic oxygen reduction catalyst according to any one of claims 1-8 in the oxygen reduction reaction at the cathode of a zinc-air battery.
10. The application according to claim 9, characterized in that, The method is as follows: In an alkaline electrolyte solution, a zinc-air battery is constructed using carbon cloth coated with an iron-gallium bimetallic oxygen reduction catalyst FeGa-NC as the air cathode and zinc foil as the anode; the alkaline electrolyte solution is a 5M-7M KOH solution containing 0.1M-0.3M Zn(OAc)2.