Opportunity
The increasing global demand for clean and sustainable energy conversion technologies, such as electrochemical water splitting for hydrogen production, faces significant challenges due to the limitations of current electrocatalysts. Traditional noble-metal-based catalysts (e.g., Pt/C for HER and IrO₂/RuO₂ for OER) suffer from high costs, scarcity, and poor stability under harsh acidic conditions, particularly in proton exchange membrane (PEM)-based electrolyzers. Additionally, most existing high-entropy alloy (HEA) nanostructures are limited to thermodynamically stable face-centered cubic (fcc) phases, which restricts their catalytic performance. There is a critical need for low-cost, highly efficient, and stable electrocatalysts with unconventional crystal phases to overcome these limitations and enable large-scale industrial applications.
Technology
This patent introduces a low-temperature, facile, and general wet-chemical method for synthesizing unconventional-phase HEA nanostructures with 5–10 metallic components. The method involves epitaxial growth of a HEA shell on nanocores (e.g., 4H-Au nanowires or 2H/fcc-Au nanosheets) using metal precursors, reducing agents, and surfactants.
Key innovations include:
1. Phase Control: The synthesis of HEA nanostructures with unconventional 4H or 2H/fcc heterophases, which exhibit superior catalytic properties compared to traditional fcc-phase HEAs.
2. Scalability: A simple, reproducible, and scalable process that operates at lower temperatures (250–280°C) compared to conventional thermal-shock methods (2000 K).
3. Compositional Diversity: The ability to tailor compositions by adjusting precursor ratios, enabling the creation of quinary to denary (5–10 elements) HEA nanostructures (e.g., IrPtNiCoFe, IrPtNiCoFeRhPdRuCuMn).
4. Core-Shell Design: The 4H-Au core stabilizes the HEA shell during electrocatalysis, preventing structural degradation under high-current-density conditions.
Advantages
- Low-Cost & Scalable: Uses wet-chemical synthesis at lower temperatures, reducing energy consumption and enabling large-scale production.
- Enhanced Catalytic Performance: Unconventional 4H/2H phases offer optimized electronic structures and undercoordinated active sites for HER/OER.
- Superior Stability: Core-shell design prevents aggregation/dissolution during long-term electrolysis, especially in acidic PEM environments.
- Versatility: Applicable to diverse electrochemical reactions (HER, OER, ORR, AOR, FAOR) and pH-universal conditions (acidic/alkaline).
- In Situ Monitoring: Thin HEA shell enables surface-enhanced Raman scattering (SERS) for real-time reaction mechanism studies.
Applications
- Green Hydrogen Production: Bifunctional catalysts for PEM-based water electrolyzers.
- Fuel Cells: Cathode/anode materials for acidic/alkaline fuel cells.
- Industrial Electrocatalysis: Alcohol oxidation, CO₂ reduction, and chemical synthesis.
- SERS Platforms: In situ detection of molecular adsorption/desorption during catalysis.
- Energy Storage: Components for batteries and supercapacitors.
