Fluorinated modified supported ruthenium-based fuel cell anode catalyst and its preparation method
By introducing a fluorination process into the preparation of Ru-based catalysts, and utilizing the fluoride ion regulation effect and HF etching, the problems of easy flooding and low stability of Ru-based catalysts in alkaline media are solved, achieving improved high activity and long-term stability. This method is applicable to Ru-based catalysts with various oxide supports.
Patent Information
- Application Number
- CN202610429574.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-02
- Publication Date
- 2026-06-26
AI Technical Summary
Existing Ru-based supported catalysts are prone to water flooding in alkaline hydroxide reactions, leading to decreased reaction kinetics and limited battery power output. Furthermore, existing modification methods struggle to precisely control the hydrophilicity/hydrophobicity of the interface while ensuring high dispersion of the Ru active component, thus affecting their long-term stability.
By introducing a fluorine source (such as ammonium fluoride) during the reduction process of metal oxide precursors, and utilizing the anion regulation effect at high temperature and the etching effect of HF, the surface water environment of the catalyst is precisely modified, thus preparing a fluorinated modified supported ruthenium-based fuel cell anode catalyst.
It significantly improves the hydrogenation reaction activity of the catalyst over a wide potential range, enhances the long-term operational stability of the catalyst, simplifies the preparation process, and is suitable for Ru-based systems supported on various transition metal oxides.
Smart Images
Figure CN122291552A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of alkaline hydrogen fuel cell catalyst preparation technology, specifically providing a fluorinated modified supported ruthenium-based fuel cell anode catalyst and its preparation method. Background Technology
[0002] With the deepening development of the hydrogen economy, anion exchange membrane fuel cells (AEMFCs) have become a research hotspot in the fuel cell field. They can utilize non-platinum precious metal catalysts and possess advantages such as faster alkaline kinetics and lower system costs. In the development of AEMFCs, anion exchange polymer membranes and cathode oxygen reduction catalysts have gradually matured. Therefore, the kinetic efficiency of the anolyte oxidation-hydrogenation reaction (HOR) has become a key factor determining the overall energy conversion rate of the battery. Ru-based supported catalysts, due to their unique electronic structure and excellent metal-support synergistic effect, show significant application potential in alkaline HOR environments.
[0003] However, existing Ru-based supported catalysts still face the following severe challenges in actual operation: Ru-based catalysts and their oxide supported layers TiO2 or ZrO2 are usually highly hydrophilic. During the AEMFC anode reaction, due to the high binding energy between the generated water molecules and the catalyst surface, water tends to accumulate at the active sites, leading to a "flooding" phenomenon. This phenomenon not only hinders the diffusion and mass transfer of hydrogen to the Ru active sites, but also covers the effective three-phase interface, resulting in a significant decrease in reaction kinetics and severely limiting the power output of the battery at high current densities.
[0004] Currently, there are few methods for regulating the surface and interfacial water environment of Ru-based catalysts, and existing modification processes are complex and difficult to control precisely. Traditional modification methods often fail to achieve precise control of the interfacial hydrophilicity / hydrophobicity while ensuring high dispersion of Ru active components. In particular, the interfacial water exchange efficiency of Ru-based catalysts directly affects their long-term stability and activity maintenance over a wide potential range.
[0005] Therefore, developing a method that can precisely control the water environment at the catalyst surface in a ruthenium-based supported system through a simple process is of great scientific significance and application value for overcoming the performance bottleneck of the AEMFC anode HOR and improving the utilization rate and long-term stability of ruthenium-based catalysts. Summary of the Invention
[0006] The purpose of this invention is to provide a fluorinated modified supported ruthenium-based fuel cell anode catalyst and its preparation method, to solve the problems of existing ruthenium-based anode catalysts in alkaline media, such as easy flooding, low stability, and limited hydrogen evolution / hydrogen oxidation (HOR) activity under high current. This invention innovatively proposes a fluorination process that introduces a fluorine source (such as ammonium fluoride) during the reduction of metal oxide precursors, utilizing the anion (fluoride ion) regulation effect at high temperature and the etching effect of HF to achieve precise modification of the catalyst. This invention not only significantly improves the HOR activity of the catalyst over a wide potential range, but also greatly enhances its long-term operational stability.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] A fluorinated modified supported ruthenium-based fuel cell anode catalyst, characterized in that the active components of the anode catalyst are an oxide support and Ru nanoparticles supported on the support, and the oxide support is doped with fluorine ions through a fluorination process.
[0009] Furthermore, the loading of Ru nanoparticles in the active component is 5-20 wt% of the oxide support mass.
[0010] Furthermore, the oxide support is ZrO2 or anatase TiO2.
[0011] Meanwhile, the present invention provides a method for preparing the above-mentioned fluorinated modified supported ruthenium-based fuel cell anode catalyst, characterized by comprising the following steps:
[0012] Step 1. Prepare supported Ru-based oxide precursor powder by gelation method, and grind it after cleaning and drying for later use;
[0013] Step 2. Mix and grind the precursor powder with the fluorine-containing compound to form a mixed powder;
[0014] Step 3. Place the mixed powder in a tube furnace and calcine it at high temperature under a reducing atmosphere; after natural cooling to room temperature in the furnace, a fluorinated and modified supported ruthenium-based fuel cell catalyst is obtained.
[0015] Furthermore, in step 1, the precursor is either Ru-O-Ti or Ru-O-Zr.
[0016] Furthermore, in step 1, the preparation process of the precursor powder is as follows: solution A containing Ru active component and solution B containing metal oxide loaded component are prepared respectively. Solution A is added dropwise to solution B and stirred to form a uniform gel. After demulsification, washing, drying and grinding, the precursor powder is obtained.
[0017] Furthermore, the active Ru component is RuCl3, and the metal oxide supporting component is zirconium propoxide or tetrabutyl titanate.
[0018] Furthermore, in step 2, the fluorinated compound is ammonium fluoride, and the mass ratio of the precursor powder to ammonium fluoride is 25:1 to 1:1.
[0019] Furthermore, in step 3, the high-temperature calcination treatment is carried out at a temperature of 400–600°C, a heating rate of 2–10°C / min, and a time of 1–3 hours.
[0020] Furthermore, in step 3, the reducing atmosphere is a mixture of hydrogen and nitrogen, wherein the volume fraction of hydrogen is 5-15%.
[0021] Based on the above technical solution, the beneficial effect of the present invention is to provide a supported ruthenium-based fuel cell anode catalyst with fluorination process control and its preparation method, which has the following advantages:
[0022] 1) Significantly enhanced electrochemical activity of the catalyst: By introducing F for anion regulation during high-temperature reduction, the surface electronic structure of the Ru active site was optimized; the prepared catalyst showed a Faraday peak current in 0.1M KOH electrolyte that was more than 1.5 times higher than that of the unmodified control group; the catalyst exhibited higher current density and faster reaction kinetics over a wide potential range, effectively solving the problem of slow anode reaction in anion exchange membrane fuel cells (AEMFC);
[0023] 2) Significantly improves the electrochemical stability of the catalyst: The catalyst prepared by this invention showed a gradual current decay trend in the 80-hour constant potential test (CA); it could still maintain a high current output in the high potential region of the LSV test, which indicates that the fluorination process not only improved the initial activity, but also improved the structural stability of the catalyst under actual working conditions by enhancing the interaction between the Ru active component and the oxide support.
[0024] 3) The process is simple and highly universal: The present invention adopts a process flow of grinding and mixing, one-step reduction and in-situ passivation, which does not require complex synthesis equipment. The operation process is simple and highly controllable. Moreover, the fluorination process is not only applicable to the Ru-O-Ti system, but also shows a consistent activity enhancement effect in Ru-based systems supported by various transition metal oxides such as Ru-O-Zr, which has broad prospects for industrial application. Attached Figure Description
[0025] Figure 1 The diagram shows the catalyst performance of the fluorinated supported Ru-O-Ti anode catalysts in Examples 1 and 2 of this invention.
[0026] Figure 2The diagram shows the catalyst performance of the fluorinated supported Ru-O-Ti anode catalysts in Examples 3, 4, and 5 of this invention.
[0027] Figure 3 The diagram shows the catalyst performance of the fluorinated supported Ru-O-Zr anode catalysts in Examples 6 and 7 of this invention.
[0028] Figure 4 The figures show the galvanostatic test curves of the fluorinated supported Ru-O-Ti anode catalysts in Examples 3 and 4 of this invention. Detailed Implementation
[0029] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0030] Example 1
[0031] This embodiment provides a fluorinated supported ruthenium-based fuel cell anode catalyst, specifically a fluorinated Ru-O-Ti catalyst, prepared by the following steps:
[0032] Step 1. Precursor preparation;
[0033] Elemental ruthenium was dissolved in concentrated hydrochloric acid and diluted to volume with deionized water to prepare a RuCl3 solution with a concentration of 37 mg / mL. 9.46 mL of the RuCl3 solution was mixed with 12.54 mL of anhydrous ethanol to form solution A, and 8 mL of tetrabutyl titanate was mixed with 80 mL of anhydrous ethanol to form solution B. Using a solvent gelation method, solution A was added dropwise to solution B, and the mixture was stirred continuously at room temperature for 30 min to form a homogeneous gel. Subsequently, 1.4 mL of acetic acid, 2 mL of formamide, and 50 mL of propylene oxide were added sequentially to the gel to break the emulsion, and the mixture was reacted at 65°C in a sealed environment for 4 h. The reaction product was centrifuged, washed three times alternately with anhydrous ethanol and deionized water, dried at 60°C, and ground to obtain Ru-O-Ti precursor powder.
[0034] Step 2. Mixing of NH4F;
[0035] Weigh 0.1 g of the above Ru-O-Ti precursor powder, add NH4F at a mass ratio of 25:2, place the mixture in an agate mortar and grind it thoroughly to ensure that the fluorine source is in close contact with the surface of the precursor particles and is evenly distributed to form a mixed powder.
[0036] Step 3. High-temperature reduction treatment;
[0037] The ground powder from step 2 is spread evenly in a crucible ceramic boat and placed in the center of a tube furnace. After evacuation, the temperature is raised to 500°C at a rate of 5°C / min under a mixed reducing atmosphere of H2 and N2 (H2 volume fraction of 10%), and held at this temperature for 2 hours to complete the high-temperature reduction. During the reduction process, the gas flow ratio is strictly controlled to H2:N2=10:90.
[0038] The reaction system was naturally cooled to room temperature in the furnace under a reducing atmosphere, and the product was directly removed to obtain the fluorinated supported Ru-O-Ti anode catalyst.
[0039] Example 2
[0040] This embodiment also provides a fluorinated modified supported ruthenium-based fuel cell anode catalyst, the only difference from Example 1 being that in step 2, the mass ratio of Ru-O-Ti precursor powder to NH4F is 8:1.
[0041] Example 3
[0042] This embodiment also provides a fluorinated modified supported ruthenium-based fuel cell anode catalyst, the only difference from Example 1 is that in step 2, the mass ratio of Ru-O-Ti precursor powder to NH4F is 4:1.
[0043] Example 4
[0044] This embodiment also provides a fluorinated modified supported ruthenium-based fuel cell anode catalyst, the only difference from Example 1 being that in step 2, the mass ratio of Ru-O-Ti precursor powder to NH4F is 2:1.
[0045] Example 5
[0046] This embodiment also provides a fluorinated modified supported ruthenium-based fuel cell anode catalyst, the only difference from Example 1 being that in step 2, the mass ratio of Ru-O-Ti precursor powder to NH4F is 1:1.
[0047] Example 6
[0048] This embodiment provides a fluorinated modified supported ruthenium-based fuel cell anode catalyst, specifically a fluorinated Ru-O-Zr catalyst, prepared by the following steps:
[0049] Step 1. Precursor preparation;
[0050] 3 mL of zirconium propoxide was used as the loading component source and mixed with 20 mL of anhydrous ethanol to form solution B; 3.04 mL of RuCl3 solution (37 mg / mL) was mixed with 6.96 mL of anhydrous ethanol to form solution A; solution A was added dropwise to solution B using the solvent gelation method, and the mixture was stirred continuously at room temperature for 30 min to form a homogeneous gel; then 0.2 mL of acetic acid, 0.5 mL of formamide, and 50 mL of propylene oxide were added to the gel sequentially to demulsify, and the mixture was reacted at 65 °C in a sealed environment for 4 h; the reaction product was separated by centrifugation, then washed three times alternately with anhydrous ethanol and deionized water, dried at 60 °C, and ground to obtain Ru-O-Zr precursor powder;
[0051] Step 2. Mixing of NH4F;
[0052] Weigh 0.1 g of Ru-O-Zr precursor powder and add NH4F at a mass ratio of 4:1. Place the mixture in an agate mortar and grind it thoroughly to ensure that the fluorine source is in close contact with the surface of the precursor particles and is evenly distributed to form a mixed powder.
[0053] Step 3. High-temperature reduction treatment;
[0054] The ground powder from step 2 is spread evenly in a crucible ceramic boat and placed in the center of a tube furnace. After evacuation, the temperature is raised to 500°C at a rate of 5°C / min under a mixed reducing atmosphere of H2 and N2 (H2 volume fraction of 10%), and held at this temperature for 2 hours to complete the high-temperature reduction. During the reduction process, the gas flow ratio is strictly controlled to H2:N2=10:90.
[0055] The reaction system was naturally cooled to room temperature under a reducing atmosphere, and the product was directly removed to obtain the fluorinated supported Ru-O-Zr anode catalyst.
[0056] Example 7
[0057] This embodiment also provides a fluorinated modified supported ruthenium-based fuel cell anode catalyst, the only difference from Example 6 is that in step 2, the mass ratio of Ru-O-Zr precursor powder to NH4F is 1:1.
[0058] The fluorinated and supported ruthenium-based fuel cell anode catalysts prepared in Examples 1 to 8 are characterized and tested below. To more intuitively demonstrate the beneficial effects of the present invention, Comparative Example 1 and Comparative Example 2 are also provided.
[0059] Comparative Example 1: The Ru-O-Ti precursor powder prepared in Example 1 was taken and subjected to high-temperature reduction and in-situ passivation treatment directly according to steps 3 and 4 in Example 1 without adding any fluorine source, to obtain the Ru-O-Ti anode catalyst.
[0060] Comparative Example 2: The Ru-O-Zr precursor powder prepared in Example 2 was taken and subjected to high-temperature reduction and in-situ passivation treatment directly according to steps 3 and 4 in Example 7 without adding any fluorine source, to obtain the Ru-O-Zr anode catalyst.
[0061] 1. Electrochemical activity testing of catalysts;
[0062] Weigh 4 mg of catalyst powder and 2 mg of carbon powder, add them to a mixture of 1 mL of anhydrous ethanol and 15 μL of Nafion solution, and sonicate for 30 minutes to obtain a uniform catalyst ink. Use a pipette to take 12.5 μL of the ink and coat it evenly on the surface of a glassy carbon electrode. Dry it under an infrared lamp to obtain the working electrode. Use a standard three-electrode system with a mercury / mercury oxide electrode as the reference electrode and a carbon rod as the counter electrode. The test is carried out in a 0.1 M KOH electrolyte solution saturated with nitrogen and hydrogen. The hydrogen hydroxide (HOR) linear sweep voltammetry (LSV) test potential range is 0–0.6 V (relative to the standard hydrogen electrode), the scan rate is 10 mV / s, and the electrode rotation speed is 1600 rpm.
[0063] The fluorinated supported Ru-O-Ti anode catalysts in Examples 1 and 2 were compared, and the results are as follows: Figure 1 As shown, the fluorinated supported Ru-O-Ti anode catalysts of Examples 3, 4, and 5 were compared with the Ru-O-Ti anode catalyst of Comparative Example 1. The results are as follows: Figure 2 As shown, Figure 1 and Figure 2 All figures show the LSV curves of the catalyst in 0.1 M KOH solutions saturated with H2 and N2. As can be seen from the figures, the HOR activity of the fluorinated supported Ru-O-Ti anode catalysts in Examples 1-5 of this invention is significantly improved. The HOR activity of the catalyst reaches its peak when the mass ratio of precursor to NH4F is 8:1. Compared with Comparative Example 1, the fluorination process increases the Faraday current density of the Ru-O-Ti system by more than 1.5 times, thus proving that the introduction of F anions in this invention effectively changes the hydrophilic interfacial water environment on the catalyst surface.
[0064] The fluorinated supported Ru-O-Zr anode catalysts from Examples 6 and 7 were compared with the Ru-O-Zr anode catalyst from Comparative Example 2. The results are as follows: Figure 3 As shown, Figure 3 The figure shows the LSV curves of the catalyst in 0.1 M KOH solutions saturated with H2 and N2. As can be seen from the figure, in 0.1 M KOH solution saturated with N2, the hydrogen adsorption and desorption peak distribution of the fluorinated catalyst showed a significant shift, which confirms from an electrochemical perspective that the introduction of the F anion successfully modulates the surface electronic structure of the Ru active site. Furthermore, compared with Comparative Example 2, the activity of the fluorinated supported Ru-O-Zr anode catalyst was increased by about 2 times, further demonstrating the performance improvement effect of the fluorination process on ruthenium-based catalysts.
[0065] 2. Catalyst operational stability test;
[0066] Weigh 3 mg of catalyst and add it to 0.4 mL of anhydrous ethanol and 20 mg of Nafion solution. Sonicate for 30 minutes to obtain uniform ink. Spray the ink uniformly onto carbon paper to prepare the working electrode. Use 0.1 MKOH aqueous solution saturated with hydrogen as the electrolyte solution. Back-push the carbon paper with hydrogen and set a constant potential of 0.65 V (relative to the standard hydrogen electrode). Test using potentiostatic method (CA) for 80 hours and record the current decay.
[0067] The fluorinated supported Ru-O-Ti anode catalysts from Examples 3 and 4 were compared with the Ru-O-Ti anode catalyst from Comparative Example 1. The results are as follows: Figure 4 As shown in the figure, during the continuous potentiostatic test (CA) lasting up to 80 hours, the fluorinated supported Ru-O-Ti anode catalyst in Example 3 exhibited an extremely high current retention rate and a very gentle decay trend; while the Ru-O-Ti anode catalyst in Comparative Example 2 showed a performance degradation of half in about 20 hours.
[0068] In summary, this invention provides a fluorinated modified supported ruthenium-based fuel cell anode catalyst and its preparation method. The fluorination process, which introduces a fluorine source (such as ammonium fluoride) during the reduction of metal oxide precursors, can solve the problems of easy flooding, low stability, and limited hydrogen evolution / hydrogen oxidation (HOR) activity of existing ruthenium-based anode catalysts in alkaline media. It not only significantly improves the HOR activity of the catalyst over a wide potential range, but also greatly enhances its long-term operational stability.
[0069] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.
Claims
1. A fluorinated modified supported ruthenium-based fuel cell anode catalyst characterized in that, The active components of the anode catalyst are an oxide support and Ru nanoparticles supported on the support, and the oxide support is doped with fluorine ions through a fluorination process.
2. The fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 1, characterized in that, The loading of Ru nanoparticles in the active component is 5-20 wt% of the oxide support mass.
3. The fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 1, characterized in that, The oxide support is ZrO2 or anatase TiO2.
4. The method for preparing the fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 1, characterized in that, Includes the following steps: Step 1. Prepare supported Ru-based oxide precursor powder by gelation method, and grind it after cleaning and drying for later use; Step 2. Mix and grind the precursor powder with the fluorine-containing compound to form a mixed powder; Step 3. Place the mixed powder in a tube furnace and calcine it at high temperature under a reducing atmosphere. Then, allow it to cool naturally to room temperature to obtain a fluorinated and modified supported ruthenium-based fuel cell anode catalyst.
5. The method for preparing the fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 4, characterized in that, In step 1, the precursor is either Ru-O-Ti or Ru-O-Zr.
6. The method for preparing the fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 4, characterized in that, In step 1, the preparation process of the precursor powder is as follows: solution A containing Ru active component and solution B containing metal oxide loading component are prepared respectively. Solution A is added dropwise to solution B and stirred to form a uniform gel. After demulsification, washing, drying and grinding, the precursor powder is obtained. The Ru active component is RuCl3 and the metal oxide loading component is zirconium propoxide or tetrabutyl titanate.
7. The method for preparing the fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 4, characterized in that, In step 2, the fluorinated compound is ammonium fluoride, and the mass ratio of the precursor powder to ammonium fluoride is 25:1 to 1:
1.
8. The method for preparing the fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 4, characterized in that, In step 3, the high-temperature calcination treatment is carried out at a temperature of 400–600℃, a heating rate of 2–10℃ / min, and a time of 1–3h.
9. The method for preparing the fluorinated modified supported ruthenium-based fuel cell anode catalyst according to claim 4, characterized in that, In step 3, the reducing atmosphere is a mixture of hydrogen and nitrogen, wherein the volume fraction of hydrogen is 5-15%.