Anionic Regulated NiFe (Oxy)Sulfide Electrocatalysts for Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Efficient oxygen evolution reaction (OER) electrocatalysts are crucial for sustainable energy technologies like fuel cells, metal-air batteries, and water splitting.
• Current OER catalysts face limitations in efficiency and stability, hindering widespread adoption.

Purpose of the Study:

• To investigate the impact of anionic regulation on the OER performance of nickel-iron sulfide (NiFeS) electrocatalysts.
• To demonstrate a novel strategy for enhancing electrocatalyst activity through controlled modulation of active sites.

Main Methods:

• Fabrication of NiFeS electrocatalysts with systematically varied sulfur-to-oxygen atomic ratios.
• Electrochemical characterization, including overpotential measurements and kinetic analysis (Tafel slope), to evaluate OER performance.

Main Results:

• A volcano plot relationship was observed between sulfur content and OER overpotential, indicating an optimal S:O ratio.
• The optimized NiFeS-2 electrocatalyst achieved a low OER overpotential of 286 mV at 10 mA cm⁻².
• The optimized catalyst exhibited fast OER kinetics with a Tafel slope of 56.3 mV dec⁻¹, representing state-of-the-art performance.

Conclusions:

• Anionic regulation by tuning the S:O ratio is a highly effective strategy for designing superior OER electrocatalysts.
• This approach provides fundamental insights into the electronic and atomic-level mechanisms governing electrocatalysis.
• The developed NiFeS electrocatalysts show significant promise for applications in sustainable energy conversion devices.