AEM water electrolysis hydrogen production membrane electrode based on gallium-based high-entropy oxide catalyst and preparation method of AEM water electrolysis hydrogen production membrane electrode

Abstract

The invention belongs to the technical field of green hydrogen energy, and particularly relates to a gallium-based high-entropy oxide membrane electrode based on regulation and control of a liquid gallium substrate and a preparation method of the gallium-based high-entropy oxide membrane electrode. According to the membrane electrode, liquid gallium microdroplets with the diameter of 25 + / -5 microns are formed on pretreated carbon paper through electro-deposition, multi-element transition metal ions are adsorbed, and a core-shell structure Ga2O3 (at) HEO anode catalyst is synthesized in situ by combining a gradient heat treatment process; a Gd < 3 + > / Na < + > doping strategy is innovatively introduced to regulate and control an electronic structure, and oxygen vacancy formation energy is reduced to 0.9 eV. The oxygen evolution overpotential is as low as 398 mV under the industrial grade current density of 500 mA / cm < 2 >, the neutral environment overpotential is 452 mV, and the attenuation is lt after 1500 hours; 5%, life gt; and the time is 20,000 hours. The technology is compatible with an electrolytic cell, a fuel cell and a metal-air cell, the problems of element segregation and agglomeration in low-temperature synthesis of a high-entropy material are solved, and a high-performance and low-cost solution is provided for large-scale production of green hydrogen.

Description

Technical Field

[0001] The present invention belongs to the field of green hydrogen production technology, and specifically relates to the structural innovation and preparation process of a membrane electrode (MEA), the core component of an anion exchange membrane (AEM) water electrolysis hydrogen production system. In particular, the present invention focuses on the use of liquid gallium (Ga)-induced synthesis of multi-element doped gallium-based high entropy oxide (Ga2O3@HEO) as an anodic oxygen evolution reaction (OER) catalyst. Through elemental composition optimization, core-shell structure design and low-temperature gradient heat treatment process, the present invention constructs an industrial-grade high current density (>500 mA / cm 2 ) AEM membrane electrode system. This technology addresses the industry pain points of insufficient activity of traditional transition metal catalysts and the high cost of precious metal catalysts. It also overcomes the challenges of particle agglomeration and phase separation in high-entropy material synthesis, providing a high-performance, low-cost solution for large-scale green hydrogen production. Background Art

[0002] Anion exchange membrane (AEM) water electrolysis hydrogen production technology has become a research hotspot in the field of green hydrogen production due to its compatibility with non-precious metal catalysts, adaptability to alkaline environments, and cost advantages. However, its industrialization still faces severe challenges: First, the anodic oxygen evolution reaction (OER) involves a four-electron transfer process, and the kinetic energy barrier is much higher than that of the cathodic hydrogen evolution reaction (HER). Commercial AEM electrolyzers operate at 500 mA / cm 2 The anode overpotential generally exceeds 450 mV at the current density, resulting in a system energy consumption as high as 4.8–5.2 kWh / Nm 3 -H2. Secondly, traditional transition metal oxide catalysts (such as NiO and Co3O4) are susceptible to lattice oxygen loss during long-term operation in high-temperature alkaline environments (60–80°C, 6 M KOH), resulting in activity degradation exceeding 20%. Precious metal catalysts (IrO2 / RuO2), while offering excellent performance, are expensive (>¥3000 / g), severely hindering their large-scale application.

[0003] High entropy oxides (HEOs) offer a new path to break through the bottleneck of OER catalysts due to their unique "cocktail effect," lattice distortion, and delayed diffusion properties. However, existing HEO synthesis technologies have significant limitations: traditional solid-phase methods require high temperatures above 1300K to maintain the entropy increase driving force, leading to particle agglomeration (particle size > 500 nm) and a sharp drop in specific surface area (<10m 2 / g); Due to elemental segregation, the purity of HEO with a pentavalent or higher purity is less than 70%. Furthermore, powdered catalysts require a binder (such as Nafion) to be loaded onto the electrode, increasing interfacial resistance and blocking active sites.

[0004] Recent breakthrough research shows that the self-generated Ga2O3 layer on the surface of liquid gallium can serve as an ideal substrate to solve the above problems: the oxide layer is very sensitive to transition metal ions (Mn 2+ / Fe 3+ / Co 2+ / Ni 2+ The core-shell structure Ga2O3@HEO (such as Mn) can be generated by electroplating on the carbon paper surface to form micron-sized gallium droplets (diameter 25±5 μm) and heat-treating at 400℃. 0.65 Fe 0.59 Co 0.83 Ni 0.48 Zn 0.45 O4), whose interfacial lattice strain (0.124 Å) significantly reduces the OER rate-determining step (O→OOH) energy barrier by 0.28 eV. 2 The overpotential is reduced to 408 mV. Nevertheless, this technology can be used at industrial current densities (>500 mA / cm 2 ) is still insufficient, and the elemental composition is not optimized to regulate the lattice oxygen activation mechanism (LOM).

[0005] The latest progress in the industry points the way to performance optimization: Shandong University of Technology introduces Na into NiFeCoMn hydroxide + (5 at%), the O–O coupling energy barrier is reduced by 0.15 eV to achieve 176 mV@10 mA / cm by forming a non-bonded oxygen band through O 2p–Na 3s orbital hybridization. 2 Ultra-low overpotential; the Beijing University of Science and Technology team confirmed that Gd 3+ Doping with Gd (3 at%) can reduce the oxygen vacancy formation energy of NiO (1.7 eV→0.9 eV), promote the LOM pathway, and reduce the Tafel slope to 42 mV / dec. However, existing patented technologies still have drawbacks: high-entropy hydroxides have poor conductivity in alkaline environments (<10 S / cm); and Gd doping strategies are limited to binary systems and fail to exploit the high-entropy synergistic effect.

[0006] In summary, it is urgent to develop an AEM membrane electrode with high activity, high stability and industrial applicability: optimize the electronic structure of HEO by integrating liquid gallium substrate synthesis technology with Na / Gd doping strategy; design a low-temperature gradient heat treatment process to suppress particle agglomeration; construct a low-impedance membrane electrode assembly to match 500 mA / cm 2 Level current density operation requirements. Summary of the Invention

[0007] In order to better explain the present invention, exemplary embodiments of the present invention will be described in more detail below. Although exemplary embodiments of the present invention are shown below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to enable the scope of the present invention to be fully conveyed to those skilled in the art. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0008] This invention provides a thin-layer high-entropy oxide (HEO) membrane electrode (MEA) controlled by a liquid gallium substrate and its preparation method, which is used for catalyzing the oxygen evolution reaction (OER) in anion exchange membrane (AEM) water electrolysis hydrogen production systems. Its core innovation lies in utilizing the self-generated Ga2O3 layer on the surface of liquid gallium as a multi-element anchoring substrate, combined with an element doping strategy and gradient heat treatment process, to achieve low-temperature controllable synthesis and membrane electrode integration of a high-performance core-shell structured Ga2O3@HEO catalyst. The preparation method of the Ga2O3@HEO MEA specifically includes the following key steps: S1, carbon paper substrate pretreatment; S2. Liquid gallium electrodeposition and morphology control; S3, multi-metal ion adsorption and ratio control; S4, gradient heat treatment and crystal phase control; S5. Industrial integration of membrane electrode.

[0009] Furthermore, in S1, the carbon paper substrate pretreatment further includes the following steps: S1-1, plasma activation modification; S1-2. Electrode surface activation.

[0010] The specific steps for carbon paper substrate pretreatment are as follows: S1-1, Plasma activation modification: Commercial carbon paper (300 μm thick) was immersed in anhydrous ethanol and ultrasonically cleaned for 15 minutes to remove organic residue on the surface. After drying with nitrogen, the paper was placed in a plasma treatment chamber and treated at 200 W RF power for 10 minutes using an argon-oxygen mixture (Ar:O2 = 4:1, flow rate 50 sccm).

[0011] S1-2. Electrode surface activation: The modified carbon paper was immersed in 0.1 M dilute nitric acid solution for 30 seconds, washed with deionized water three times, and dried in a vacuum oven at 80°C for 1 hour.

[0012] Furthermore, in S2, liquid gallium electrodeposition and morphology control further include the following steps: S2-1, electrochemical stripping of the oxide layer; S2-2. Precise construction of micron gallium droplets.

[0013] The specific steps of liquid gallium electrodeposition and morphology control are as follows: S2-1, electrochemical stripping of oxide layer: Prepare a 1.5 M NaOH electrolyte (temperature 25 ± 1°C), place liquid gallium (99.99% purity) in the platinum anode tank, and fix carbon paper in the cathode tank. Apply a 5 V DC voltage for 10 minutes to trigger the reaction: Ga2O3+2NaOH+3H2O→2Na[Ga(OH)4] Real-time monitoring of current density is stable at 25±3 mA / cm 2 .

[0014] S2-2. Precision construction of micron gallium droplets: The voltage was reduced to 3 V, and the electrodeposition time was 5 minutes. Driven by the electric field, liquid gallium was uniformly anchored on the carbon paper fibers as spherical droplets with a diameter of 25 ± 5 μm. By adjusting the voltage (1-5 V) and time (1-10 minutes), a droplet size CV of <10% was achieved.

[0015] Furthermore, in S3, the multi-metal ion adsorption and ratio control further includes the following steps: S3-1, preparing transition metal salt solution; S3-2. Surface energy drives adsorption.

[0016] The specific steps for multi-metal ion adsorption and ratio control are as follows: S3-1. Preparation of transition metal salt solution Weigh nitrate (total concentration 0.8 M) in a molar ratio of Mn:Fe:Co:Ni:Zn = 0.65:0.59:0.83:0.48:0.45 and dissolve it in a 3:1 ethylene glycol-water mixture. Add 0.1 M sodium citrate as a dispersant and stir magnetically for 30 minutes until a clear solution is obtained.

[0017] S3-2, Surface energy driven adsorption: The gallium-loaded carbon paper was vertically immersed in the metal salt solution and kept at a constant temperature of 25°C for 120 minutes.

[0018] Furthermore, in S4, the gradient heat treatment and crystal phase control further include the following steps: S4-1, inert atmosphere pre-diffusion; S4-2, construction of reducing atmosphere vacancies; S4-3, crystalline phase transformation in oxidizing atmosphere.

[0019] The specific steps of gradient heat treatment and crystal phase control are as follows: S4-1. Inert atmosphere pre-diffusion: The sample was placed in a tube furnace, and high-purity nitrogen (flow rate 200 sccm) was passed through it. The temperature was increased to 250°C at a rate of 5°C / min and kept at this temperature for 30 minutes.

[0020] S4-2, Reducing atmosphere vacancy construction: The gas flow rate was switched to Ar / H2 mixed gas (95:5, 150 sccm), and the temperature was increased to 350°C at a rate of 3°C / min and maintained at that temperature for 60 minutes.

[0021] S4-3, Oxidizing atmosphere crystal phase transformation: The atmosphere was switched to air (flow rate: 300 sccm), and the temperature was increased to 400°C at a rate of 2°C / min and maintained at that temperature for 120 minutes.

[0022] Furthermore, in S5, the membrane electrode industrial integration also includes the following steps: S5-1, cathode catalyst spraying; S5-2. Low temperature hot pressing of anion membrane.

[0023] The specific steps for industrial integration of membrane electrode are as follows: S5-1, cathode catalyst spraying: After the anode assembly was cooled to room temperature, Pt / C slurry (loading 0.5 mg / cm 2 , slurry solid content 20 wt%), and pre-dried at 60 °C for 10 minutes.

[0024] S5-2, Anion membrane low temperature hot pressing: A quaternized polyaromatic piperidine anion membrane (50 μm thickness, ionic conductivity >80 mS / cm) was placed between the anode and cathode, and a pressure of 1 MPa was applied in a hot press at 80°C for 90 seconds.

[0025] This invention combines for the first time the element anchoring effect of the liquid gallium substrate, the electronic structure modulation of Gd / Na doping and the gradient crystal phase evolution, overcoming the three major technical bottlenecks of element segregation, particle agglomeration and insufficient industrial-grade current density performance in the low-temperature synthesis of high-entropy materials, and providing a membrane electrode solution with high activity, long life and low cost for the large-scale production of green hydrogen.

[0026] By integrating liquid gallium substrate synthesis technology, element doping control strategy, and gradient heat treatment process, this invention has achieved breakthrough progress in the field of hydrogen production by anion exchange membrane water electrolysis. Its core beneficial effects are reflected in the following aspects: 1. Major breakthrough in catalytic performance: Based on Gd or Na doped Ga2O3@HEO core-shell catalyst, at 500 mA / cm 2At industrial-grade current density, the overpotential of the oxygen evolution reaction dropped significantly to 380 mV, which is 15.6% lower than that of traditional transition metal oxide catalysts and better than the benchmark value of precious metal IrO2. The catalyst exhibited an ultra-low Tafel slope of 48-53 mV / dec, confirming that the synergistic effect of lattice strain and doping elements reduced the OER rate-determining step energy barrier by 37.8%. After continuous operation for 1500 hours at a high temperature of 60°C and a strong alkaline environment of 1M KOH, the activity decay was strictly controlled within 5%, which was attributed to the cocktail effect of the HEO shell to inhibit element segregation, and the structural support of the Ga2O3 core to slow down the loss of lattice oxygen. More noteworthy is that the catalyst maintains excellent performance in alkaline to neutral electrolytes, 500 mA / cm 2 The overpotential fluctuation under current density is less than 10%, breaking through the traditional catalyst's dependence on a strong alkaline environment.

[0027] 2. Disruptive innovation in the manufacturing process: The unique three-step gradient heat treatment process successfully replaces the traditional 1300K high-temperature sintering process through a precise temperature control sequence of 250°C nitrogen environment, 350°C argon-hydrogen mixed gas, and 400°C air, reducing energy consumption by 67%. This process precisely controls the particle size within the range of 50-200 nanometers, and increases the specific surface area to 35 m 2 / g, and the active site density is as high as 3.2×10 15 sites / cm 2 , completely solving the problem of particle agglomeration caused by high temperatures. The strong adsorption energy of the liquid gallium substrate for multi-element metal ions ensures that the phase purity of the five-element high-entropy oxide exceeds 95% and the element segregation is less than 5%, significantly surpassing the uniformity level of solution synthesis. The innovative electrodeposition process directly grows the catalyst on the surface of plasma-activated hydrophobic carbon paper, eliminating the traditional powder coating step and reducing the interface resistance to 0.18 Ω·cm 2 , the reduction is 40%, making the membrane electrode at 1000mA / cm 2 It can run stably for 200 hours at ultra-high current density, and the voltage fluctuation is controlled within 2%.

[0028] 3. Revolutionary improvement in industrial value: In terms of material cost, the anode catalyst uses a combination of cheap transition metals and liquid gallium, with a unit dosage of 1.5 g / m 2, the cost is controlled at 790 yuan / square meter; with a 50-micron-thick quaternized polyaromatic piperidine anion membrane, the cost is 300 yuan / square meter, and the comprehensive cost of the membrane electrode is reduced to 1,200 yuan / square meter, which is 88% lower than the cost of the precious metal IrO2-based electrode. In terms of energy consumption and production efficiency, the overpotential is reduced by 80 mV, which reduces the electricity consumption per ton of hydrogen production by 200 kWh; the gradient heat treatment time is shortened from 12 hours in the traditional process to 4 hours, and the single-line production capacity is increased by 200%; the low-temperature hot pressing process is fully compatible with existing production lines, and the modification cost is less than 500,000 yuan / production line. In terms of environmental friendliness, the synthesis process avoids the use of strong corrosive reagents such as hydrofluoric acid and hydrochloric acid throughout the process, the COD value of the wastewater is controlled below 50 mg / L, and the carbon footprint of each ton of green hydrogen is reduced to 0.2 tons of carbon dioxide, which is only 2% of the coal-to-hydrogen process.

[0029] Conclusion Breakthrough: This technology system successfully overcomes the global challenges of low-temperature synthesis of high-entropy materials and element segregation control through three core innovations: liquid gallium substrate anchoring, Gd / Na doping control, and gradient crystal phase evolution. 2 The technology achieves exceptional performance with an overpotential below 380 mV and a decay of less than 5% over 1500 hours at current densities, reducing the overall membrane electrode cost to one-tenth that of conventional solutions. This technology can reduce the cost of hydrogen production from an AEM electrolyzer to $2.1 per kilogram of hydrogen, extremely close to the industry's 2030 target, providing the ultimate solution for large-scale green hydrogen production that combines high performance, low cost, and environmental friendliness. DETAILED DESCRIPTION

[0030] In order to better explain the present invention, exemplary embodiments of the present invention will be described in more detail below. Although exemplary embodiments of the present invention are shown below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0031] Example 1, basic formula (Mn 0.65 Fe 0.59 Co 0.83 Ni 0.48 Zn 0.45 O4 membrane electrode) Preparation process: S1. Carbon paper pretreatment: Commercial carbon paper (Toray TGP-H-060) was ultrasonically cleaned in anhydrous ethanol for 15 min and treated with argon-oxygen plasma (200 W, Ar:O2 = 4:1) for 10 min, with a contact angle >130°; After activation with 0.1 M HNO3 for 30 seconds and vacuum drying at 80°C, the conductivity increased to 1.3 Ω·cm-2 .

[0032] S2. Gallium droplet electrodeposition: Liquid gallium (99.99%) was used as the anode and carbon paper as the cathode in 1.5 M NaOH electrolyte (25 ± 1 °C); Apply 5 V for 10 min (current density 25 ± 3 mA·cm -2 , stripping the oxide layer); Adjust to 3.0 V and deposit for 5 minutes to form gallium droplets with a diameter of 25±5 μm.

[0033] S3. Multi-metal ion adsorption: Precursor solution: 0.8 M nitrate (Mn:Fe:Co:Ni:Zn=0.65:0.59:0.83:0.48:0.45) in ethylene glycol-water (3:1), plus 0.1 M sodium citrate; After 120 minutes of static adsorption at 25°C, the adsorption capacity was 8.7±0.3 mg·cm -2 .

[0034] S4, gradient heat treatment: N2 atmosphere: 5℃·min -1 Raise the temperature to 250°C and keep it for 30 minutes (metal ion diffusion depth >50 nm); Ar / H2 (95:5): 3℃·min -1 Heat to 350℃ and keep for 60 minutes (oxygen vacancy concentration (1.2±0.1)×10 21 cm -3 ); Air atmosphere: 2℃·min -1 Heat to 400℃ and keep for 120 minutes to form Ga2O3@Mn 0.65 Fe 0.59 Co 0.83 Ni 0.48 Zn 0.45 O4 core-shell structure.

[0035] S5, membrane electrode integration: Cathode sprayed Pt / C (0.5 mg·cm -2 ); Quaternized polyaromatic piperidine anion membrane (50 μm) was sandwiched and hot pressed at 80°C / 1 MPa for 90 seconds.

[0036] Table 1 Performance Advantage Comparison More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, achieve low-temperature in-situ growth at 400°C on a liquid gallium substrate (the traditional process requires 1300°C), expand the lattice strain to 0.124 Å, reduce the O→OOH energy barrier to 0.51 eV, and reduce the overpotential by 15%.

[0037] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst controlled by dynamic phase change and its preparation method and application, the Ga2O3 core and the HEO shell form a strong chemical bond, and the interface resistance is as low as 0.18 Ω·cm 2 , bonding strength>2.5N / cm 2 .

[0038] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change and its preparation method and application have a core-shell structure that inhibits element segregation (EDS segregation degree <5%), and the oxygen vacancy concentration is stable at (1.2±0.1)×10 21 cm -3 , attenuation <5% after 1500h.

[0039] Example 2, Gd 3+ Doped high activity formula (MnFeCoNiGd-HEO) Improvement steps: S3, precursor solution added with 3 at% Gd(NO3)3 (Mn:Fe:Co:Ni:Gd=0.61:0.55:0.78:0.45:0.06); S4-3, XPS verification of Gd after heat treatment 3+ Doping reduces the oxygen vacancy formation energy to 0.9 eV.

[0040] Table 2 Performance Breakthrough Comparison More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst controlled by dynamic phase change and its preparation method and application, Gd 3+ Doping optimizes the d-band center position (XPS confirms a binding energy shift of 1.2 eV), and the synergistic lattice strain (0.126 Å) reduces the rate-determining step energy barrier to 0.51 eV, 500 mA·cm -2 The overpotential is as low as 412 mV.

[0041] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, the high entropy "cocktail effect" inhibits acidic dissolution (Co dissolution <0.05 ppm), and the overpotential in a neutral environment (1M PBS) is 455 mV (traditional HEO>520 mV).

[0042] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst controlled by dynamic phase change and its preparation method and application, Gd 3+ Improved oxygen vacancy stability (oxygen vacancy concentration increase <8.3% after 2000 hours), with a TÜV-certified lifespan of >20,000 hours.

[0043] Example 3: Neutral electrolyte formula with wide pH adaptability Improvement steps: S3, precursor solution: increase Fe content (Mn:Fe:Co:Ni:Zn=0.50:0.70:0.75:0.40:0.40); S5, the anion membrane was replaced with a sulfonic acid perfluorosulfonic acid membrane (80 μm).

[0044] Table 3 Full pH performance verification More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method, and application, has an Fe content increased to 0.70 at% to enhance pH buffering capacity, and an overpotential of 481 mV in an acidic environment.

[0045] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, the Ga2O3 core provides 1.8 GPa compressive strength, the HEO shell porosity of 35±3% ensures mass transfer, and the attenuation in an acidic environment is <12% after 500 hours.

[0046] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, has no noble metal dissolution, and the wastewater COD value is <50 mg / L.

[0047] Example 4: Traditional precious metal formula Improvement steps: S3, Precursor: Noble metal-free formula (Mn:Fe:Co:Ni:Zn=0.65:0.59:0.83:0.48:0.45); S2. The diameter of the gallium droplet is increased to 30±5 μm (reducing the specific surface area requirement).

[0048] Table 4 Cost-benefit analysis More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change and its preparation method and application achieve efficient utilization of cheap metals (Mn / Fe / Co / Ni / Zn) through liquid gallium substrate, 500 mA·cm -2 The overpotential is only 398 mV, and the active site density reaches 85.7% of that of precious metals.

[0049] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change and its preparation method and application have a material cost of only ¥620 / m 2 (precious metal base>¥19,000 / m 2 ), the unit hydrogen production cost is as low as ¥24.3 / kg-H2.

[0050] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, Ga2O3 core inhibits element dissolution (Co dissolution <0.05 ppm), and decays <7% in 1000h (noble metal >15%).

[0051] Example 5: Continuous Roller Pressing Industrial Production (40×40 cm Membrane Electrode) Mass production process optimization: S2, electrodeposition: continuous rolling of the electrode (voltage 3.2 V, speed 0.5 m / min, droplet CV < 8%); S4, heat treatment: tunnel furnace three-stage atmosphere control (N2→Ar / H2→air), timing synchronization accuracy ±5 seconds; S5. Hot pressing: multi-stage pressure (0.5 MPa / 10 s→1.0 MPa / 70 s→0.8 MPa / 10 s).

[0052] Table 5 Batch verification (50 tablets) More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, the tunnel furnace three-stage atmosphere switching synchronization accuracy of ±5 seconds (N2→Ar / H2→air), the oxygen vacancy concentration deviation <±5%, and the batch overpotential fluctuation ≤±3%.

[0053] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change and its preparation method and application, 0.5→1.0→0.8 MPa gradient pressure optimized interface pore distribution (35±3%), interface resistance 0.21±0.03Ω·cm 2 .

[0054] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method, and application have a roller conveying speed of 0.5 m / min (droplet CV <8%), a daily production capacity increase of 300%, and a single-line transformation cost of < ¥500,000.

[0055] Example 6: 20 MW-class water electrolysis hydrogen production system integration (industrial application of roller pressing process) System Configuration: Anode: Mn 0.65 Fe 0.59 Co0.83 Ni 0.48 Zn 0.45 O4 membrane electrode (40×40 cm, recipe of embodiment 5) Cathode: Pt / C loading 0.1 mg cm -2 Membrane: Quaternized polyaromatic piperidine anion membrane (50 μm) Electrolyzer: 5 MW / cell × 4 cells in parallel, total power 20 MW Preparation process: S1. Gallium droplet electrodeposition: Rolled carbon paper is continuously moved (speed 0.5 m / min) and droplets are deposited at a constant voltage of 3.2 V. Droplet diameter 30±5 μm (CV<8%, SEM verification) S2, multi-metal adsorption: Precursor: Mn / Fe / Co / Ni / Zn nitrate mixture (molar ratio 0.65:0.59:0.83:0.48:0.45) Static adsorption for 120 min (25°C), adsorption capacity 8.2±0.3 mg·cm -2 S3, gradient heat treatment: Tunnel furnace three-stage atmosphere timing control (N2→Ar / H2(95:5)→air), synchronization accuracy ±5 seconds Oxygen vacancy concentration (1.18 ± 0.05) × 10 21 cm -3 S4, membrane electrode integration: Multi-stage hot pressing (0.5 MPa / 10 s→1.0 MPa / 70 s→0.8 MPa / 10 s) Interface porosity 35±3% (mercury intrusion method) Table 6 System performance comparison More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, with a roller conveying speed of 0.5 m / min combined with voltage feedback control, achieves a droplet diameter CV < 8%, ensuring a 20 MW system overpotential fluctuation of ≤ ±3% (traditional ±10%).

[0056] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst controlled by dynamic phase change and its preparation method and application, the multi-stage hot pressing process reduces the interface resistance to 0.21±0.03 Ω·cm 2 , the electricity consumption per ton of hydrogen is 4.3 kWh.

[0057] More optimally, the gold-cobalt-cerium oxide composite hydrogen evolution catalyst regulated by dynamic phase change, its preparation method and application, and the MnFeCoNiZn five-element formula achieve a unit hydrogen production cost of ¥24.3 / kg, and an LCA-certified carbon footprint of 28.6 kgCO2 / kg-H2.

[0058] The present invention relates to the field of new energy materials and electrochemical technology, specifically providing a high-entropy oxide film electrode based on a liquid gallium substrate and its application in energy conversion and storage devices. It has the following application areas: 1. Water electrolysis hydrogen production system Suitable for the anode catalyst layer of alkaline / proton exchange membrane / anion exchange membrane electrolyzers, replacing precious metal catalysts (such as IrO2, RuO2).

[0059] Technical advantages: Industrial grade current density (1000 mA·cm -2 ) lower overpotential ≤ 398 mV; Electricity consumption per ton of hydrogen is 4.3 kWh (10.4% lower than that of precious metals); Lifespan > 20,000 hours (TÜV certified, precious metal based < 8,000 hours).

[0060] 2. Fuel cell system: As the oxygen reduction electrode of anion exchange membrane fuel cells (AEMFC) or the cathode catalyst of proton exchange membrane fuel cells (PEMFC).

[0061] Technical advantages: Neutral environment (1M PBS) power density 0.82 W·cm -2 (Noble metal based 0.65 W·cm -2 ); -20℃ cold start impedance <0.25 Ω·cm 2 (Conventional electrodes>0.4 Ω·cm 2 ); Co dissolution <0.05 ppm (ICP-MS verification, national standard limit 0.1 ppm).

[0062] 3. Metal-air battery: The Mn in Example 1 0.65 Fe 0.59 Co 0.83 Ni 0.48 Zn 0.45 The O4 membrane electrode serves as the dual-function air cathode of the zinc-air battery, and realizes the synergistic optimization of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) through the core-shell structure induced by the liquid gallium substrate.

[0063] Electrode architecture: Cathode layer: HEO membrane electrode coated on hydrophobic carbon paper (Toray TGP-H-060); Electrolyte: 6 M KOH + 0.2 M ZnAc2; Zinc anode: 0.3 mm thick high purity zinc foil (99.99%).

[0064] Table 7 Comparison of technical advantages This invention provides a high-entropy oxide film electrode based on dynamic phase transition control of a liquid gallium substrate, as well as its preparation method and application, belonging to the fields of new energy materials and electrochemistry. Addressing bottlenecks in the preparation of existing high-entropy materials, such as high crystallization temperature, severe element segregation, and strong dependence on precious metals, this patent achieves the industrial preparation of efficient hydrogen evolution catalysts through three innovations: low-temperature in-situ anchoring of a liquid gallium substrate, lattice strain engineering, and interface dynamics optimization.

[0065] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A gallium-based high entropy oxide film electrode based on a liquid gallium substrate, characterized in that include: Pretreated carbon paper substrate (activated by argon-oxygen plasma and treated with dilute nitric acid, contact angle > 130°); In situ grown core-shell structure anode catalyst layer (Ga2O3 core layer thickness 50-200 nm, HEO shell chemical formula Mn a Fe b Co c Ni d Zn e O x , where 0.50≤a≤0.65, 0.55≤b≤0.70, 0.75≤c≤0.83, 0.40≤d≤0.48, 0.40≤e≤0.45); Anion exchange membrane (thickness 50-80 μm, ion conductivity > 80 mS / cm); Cathode catalyst layer (Pt / C loading 0.1-0.5 mg / cm 2 The anode catalyst layer is formed by adsorbing multi-element transition metal ions through liquid gallium droplets with a diameter of 25±5 μm, and a core-shell structure with a lattice strain of 0.124-0.126 Å is formed through gradient heat treatment.

2. The membrane electrode according to claim 1, characterized in that: The HEO shell contains 3-5 at% Gd 3+ Or Na + Doping elements, including: Gd 3+ Doping reduces the oxygen vacancy formation energy to 0.9 eV, and the oxygen vacancy concentration is (1.18-1.20)×10 21 cm -3 ; Na + Doping forms an O 2p–Na 3s orbital hybrid interface with a Tafel slope of ≤43 mV / dec.

3. The membrane electrode according to claim 2, characterized in that: The interfacial bonding strength of the core-shell structure is >2.5 N / cm 2 , interface resistance ≤ 0.21 Ω·cm 2 , HEO shell porosity is 35±3%, and element segregation is <5%.

4. A method for preparing a membrane electrode according to any one of claims 1 to 3, characterized in that The following steps are involved: S1, carbon paper substrate activated by argon oxygen plasma (Ar:O2=4:1, 200W) for 10 min → treated with 0.1 M HNO3 for 30 s → dried in vacuum at 80 °C; S2, electroplating in 1.5 M NaOH electrolyte at 3.0 ± 0.2 V for 5 min to form gallium droplets with a diameter of 25 ± 5 μm; S3, immerse in a precursor solution containing 0.8 M transition metal nitrate (Mn / Fe / Co / Ni / Zn) and 0.1 M sodium citrate (ethylene glycol-water volume ratio 3:1), and allow to adsorb at 25°C for 120 minutes; S4, gradient heat treatment: in nitrogen, heat up to 250℃ at 5℃ / min and keep warm for 30min → in Ar / H2 (95:5), heat up to 350℃ at 3℃ / min and keep warm for 60min → in air, heat up to 400℃ at 2℃ / min and keep warm for 120min; S5. After the cathode is sprayed with Pt / C, it is hot pressed with the anion exchange membrane at 80°C / 0.5-1.0 MPa gradient pressure for 90 seconds.

5. The method according to claim 4, characterized in that: The metal ion molar ratio in the precursor solution of step S3 satisfies Mn:Fe:Co:Ni:Zn= 0.65:0.59:0.83:0.48:0.45, Gd 3+ Or Na + The doping amount is 3-5 at%.

6. The method according to claim 4, wherein: Step S2 adopts a roller pressing continuous process, with a conveying speed of 0.5 m / min, a voltage feedback control accuracy of ±0.2 V, and a droplet diameter variation coefficient of <8%.

7. The method according to claim 4, characterized in that: Step S5: Hot pressing implements multi-stage pressure control: 0.5 MPa for 10 seconds → 1.0 MPa for 70 seconds → 0.8 MPa for 10 seconds. The interface porosity after hot pressing is 35±3%.

8. Use of the membrane electrode according to any one of claims 1 to 3 in an AEM water electrolysis hydrogen production system, characterized in that: At 500 mA / cm 2 The oxygen evolution overpotential under current density is ≤412 mV, the overpotential in neutral environment (1M PBS) is ≤455 mV, the power consumption per ton of hydrogen is 4.3 kWh, the lifespan is >20,000 hours, and the performance degradation is <5% after 1500 hours.

9. Use of the membrane electrode according to any one of claims 1 to 3 in a fuel cell, characterized in that: Neutral environment (1M PBS) power density ≥ 0.82 W / cm 2 , -20℃ cold start impedance <0.25 Ω·cm 2 , metal ion dissolution amount <0.05ppm.

10. Use of the membrane electrode according to any one of claims 1 to 3 in a metal-air battery, characterized in that: Oxygen reduction half-wave potential ≥ 0.81 V, oxygen evolution overpotential ≤ 280 mV at 10 mA / cm², charge and discharge cycle life > 500 times (current density 50 mA / cm²) 2 ).