Oxygen-Vacancy-Driven Reactivity in Nanocrystal-Assembled NiFe₂O₄ Toward Efficient Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Developing efficient electrocatalysts is crucial for sustainable water electrolysis.
• Conventional methods often produce catalysts with limited intrinsic defects.

Purpose of the Study:

• To develop a novel in situ oxidative phase-restructuring strategy for fabricating oxygen vacancy-rich NiFe2O4 (NFO) electrocatalysts.
• To investigate the impact of intrinsic oxygen vacancies on electrocatalytic performance for the oxygen evolution reaction.

Main Methods:

• Fabrication of oxygen vacancy-rich NFO directly on nickel foam using a one-pot oxidative phase-restructuring process.
• Electrochemical characterization including overpotential and mass activity measurements.
• Durability testing over 1200 cycles.

Main Results:

• The novel NFO catalyst (NFO-1) exhibited significantly improved performance compared to its counterpart (NFO-2).
• NFO-1 showed a low overpotential of 330 mV at 20 mA cm-2 and a mass activity of 6.78 A g-1.
• The catalyst demonstrated excellent durability over 1200 cycles.

Conclusions:

• Oxidative phase restructuring is an effective strategy for engineering intrinsic defects in electrocatalysts.
• Oxygen vacancies play a key role in optimizing electronic structure and enhancing charge-transfer kinetics for efficient oxygen evolution.
• This approach offers a promising pathway for high-efficiency energy-conversion applications.