Practical H₂ supply from ammonia borane enabled by amorphous iron domain.

Area of Science:

• Materials Science
• Catalysis
• Energy Storage

Background:

• Efficient catalysis of ammonia borane (AB) is crucial for controlled hydrogen release and cost-effective hydrogen storage.
• Existing benchmarks for AB catalytic performance and stability are often limited, hindering practical applications.
• Catalyst lifetime is a critical factor for the viability of hydrogen fuel cells.

Purpose of the Study:

• To develop a highly efficient and stable catalyst for ammonia borane (AB) hydrolysis.
• To investigate the catalytic mechanism and performance of amorphous domains on metallic Fe crystal structures for hydrogen generation.
• To evaluate the catalyst's potential for practical hydrogen storage and fuel cell applications.

Main Methods:

• Synthesis of R-Fe2O3 Foam with amorphous domains on metallic Fe crystal structures.
• Characterization of catalytic performance, including turnover frequency (TOF) and hydrogen generation rates.
• Stability testing over extended periods and evaluation in a commercial car fuel cell.

Main Results:

• R-Fe2O3 Foam achieved a TOF of 113.6 min⁻¹, significantly outperforming reported benchmarks by over 20 times.
• The catalyst demonstrated exceptional stability, producing approximately 771 L H₂ in 900 h with a high volumetric rate of 43.27 mL/(min·cm²).
• Stable power outputs (7.8 V, 1.6 A) were maintained for over 5 hours in a driven commercial car fuel cell, with a H₂ supply rate of 180 mL H₂/min.

Conclusions:

• Amorphous domains on R-Fe2O3 Foam act as highly effective catalytic sites, lowering dissociation barriers for H₂O and AB via Fe-B intermediates.
• The stable Fe crystal structure contributes to the catalyst's remarkable durability and performance.
• R-Fe2O3 Foam presents a promising solution for durable, high-performance ammonia borane catalysts and viable chemical hydrogen storage in vehicles.