A Ternary Ni

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing efficient zinc-air batteries (ZABs) requires alternatives to expensive noble-metal electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).
• Transition metal-based materials are promising candidates for ORR/OER electrocatalysis.

Purpose of the Study:

• To synthesize and characterize a novel ternary NiFeCo nanoalloy catalyst for bifunctional ORR/OER applications.
• To evaluate the electrocatalytic performance of the novel catalyst in ZABs.

Main Methods:

• Supercritical reaction and heat treatment at 900 °C to produce a carbon-supported NiFeCo nanoalloy (C@NCF-900).
• Electrochemical testing in 0.1 m KOH to assess ORR/OER activity and stability.
• Performance evaluation in ZABs under continuous cycling.
• Density functional theory (DFT) calculations and in situ X-ray absorption spectroscopy (XAS) for mechanistic studies.

Main Results:

• C@NCF-900 exhibited a high ORR half-wave potential of 0.93 V in 0.1 m KOH, outperforming other transition-metal catalysts.
• The catalyst demonstrated exceptional stability with negligible activity decay after 10,000 voltage cycles.
• In ZABs, C@NCF-900 significantly outperformed a mixture of commercial Pt/C and IrO2 catalysts over 100 hours of operation.
• DFT and in situ XAS provided insights into the active sites and reaction mechanisms.

Conclusions:

• The developed C@NCF-900 nanoalloy is a highly efficient and stable bifunctional electrocatalyst for ORR and OER.
• This material shows great potential as a cost-effective alternative to noble metals in ZABs.
• The study elucidates the catalytic mechanism, paving the way for further catalyst design.