In situ Raman analysis of the NiFe/NiFe₂O₄ heterostructure for excellent oxygen evolution activity

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Oxygen evolution reaction (OER) is crucial for sustainable energy technologies.
• Developing efficient and stable OER catalysts is a significant challenge.
• Heterostructure catalysts offer unique properties for enhanced catalytic activity.

Purpose of the Study:

• To design and synthesize a NiFe/NiFe2O4 heterostructure catalyst.
• To investigate the catalytic performance and stability of the designed heterostructure for OER.
• To understand the mechanism behind the enhanced OER activity.

Main Methods:

• Synthesis of NiFe/NiFe2O4 heterostructure via annealing.
• Electrochemical characterization including OER activity and stability tests.
• Analysis of material properties and intermediate formation (FeOOH, γ-NiOOH).

Main Results:

• The NiFe/NiFe2O4 heterostructure demonstrated superior OER activity (146 mV at 10 mA cm-2) and low Tafel slope (24.11 mV dec-1).
• The catalyst exhibited excellent industrial stability, operating for over 100 hours at 500 mA cm-2.
• Annealing promoted the formation of FeOOH and the evolution of γ-NiOOH, key active species.

Conclusions:

• The NiFe/NiFe2O4 heterostructure is a highly effective catalyst for the oxygen evolution reaction.
• The study provides valuable insights into heterostructured catalyst design for improved OER performance.
• This work contributes to the advancement of catalysts for electrochemical energy conversion.