Fluoride-Induced Dynamic Surface Self-Reconstruction Produces Unexpectedly Efficient Oxygen-Evolution Catalyst.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The oxygen-evolution reaction (OER) is crucial for energy technologies like water-splitting, fuel cells, and metal-air batteries.
• Developing efficient and stable OER electrocatalysts using simple methods remains a significant challenge.

Purpose of the Study:

• To investigate in situ dynamic surface self-reconstruction for enhancing electrocatalyst activity.
• To develop a novel fluoride-incorporating NiFe hydroxide (NiFe-OH-F) nanosheet array catalyst.

Main Methods:

• A one-step hydrothermal method was used to synthesize NiFe-OH-F nanosheet arrays on Ni foam.
• In situ dynamic surface self-reconstruction was induced by fluoride leaching under OER conditions.
• Electrochemical performance was evaluated in alkaline media.

Main Results:

• The initial NiFe-OH-F catalyst required an over-potential (η) of 243 mV for 10 mA cm⁻² current density with a Tafel slope of 42.9 mV dec⁻¹.
• Surface reconstruction transformed NiFe-OH-F into a mesoporous, amorphous NiFe oxide structure.
• Post-reconstruction, OER activity increased over 58-fold, with η decreasing to 176 mV at 10 mA cm⁻² and an ultra-low Tafel slope of 22.6 mV dec⁻¹.

Conclusions:

• In situ dynamic surface self-reconstruction is a highly effective strategy for improving OER electrocatalyst performance.
• The reconstructed NiFe oxide catalyst exhibits state-of-the-art activity and stability for the oxygen-evolution reaction.
• This approach offers a promising pathway for designing advanced electrocatalysts for clean energy applications.