Active sites engineering on FeNi alloy/Cr₃C₂ heterostructure for superior oxygen evolution activity

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is vital for a sustainable hydrogen economy.
• Non-precious transition metal-based catalysts with high activity and stability are challenging to engineer.

Purpose of the Study:

• To synthesize and characterize a new FeNi-Cr3C2 heterostructure anchored on carbon sheets (FeNi-Cr3C2@C) for OER.
• To investigate the catalytic performance and stability of the novel material in alkaline media.

Main Methods:

• Synthesis of FeNi-Cr3C2@C heterostructure.
• Electrochemical characterization of OER activity, including overpotential and turnover frequency.
• Density functional theory (DFT) calculations to elucidate the catalytic mechanism.

Main Results:

• FeNi-Cr3C2@C exhibited excellent OER activity with a low overpotential (283 mV at 10 mA cm-2) and high turnover frequency (1.69 s-1 at 300 mV).
• The Cr3C2 phase improved catalyst stability by suppressing thermal coarsening and facilitated electron enrichment at Ni sites.
• DFT calculations confirmed optimized adsorption of oxygen intermediates and reduced energy barriers on the Ni active sites.

Conclusions:

• The FeNi-Cr3C2@C heterostructure is a highly active and stable electrocatalyst for OER.
• Cr3C2 acts as a beneficial support, enhancing the intrinsic activity of FeNi alloys for electrochemical reactions.
• This work presents a promising strategy for designing advanced electrocatalysts using inexpensive materials.