High-Performance Bifunctional Ni-Fe-S Catalyst in situ Synthesized within Graphite Intergranular Nanopores for...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Efficient bifunctional catalysts are crucial for large-scale energy storage via overall water splitting.
• Existing catalysts often face challenges with cost, efficiency, and stability.

Purpose of the Study:

• To develop a low-cost, efficient bifunctional catalyst for overall water splitting.
• To utilize a novel in situ synthesis strategy within a graphite substrate.

Main Methods:

• In situ synthesis of nickel and iron (di)sulfide (Ni-Fe-S) nanoparticles within the intergranular nanopores of polycrystalline graphite.
• Utilizing graphite's nanopores as nanoreactors for catalyst synthesis under mild conditions.
• Electrochemical testing in 1.0 M KOH to evaluate hydrogen and oxygen evolution reactions (HER and OER).

Main Results:

• The Ni-Fe-S composite catalyst exhibits efficient bifunctional activity for both HER and OER.
• Achieved a current density of 400 mA cm⁻² at a full cell voltage of ~2.3 V.
• Demonstrated stable performance with no significant activity decay over 24 hours of electrolysis.

Conclusions:

• The nanopore-confined in situ synthesis strategy is a promising approach for creating advanced electrocatalysts.
• The developed Ni-Fe-S catalyst is cost-effective, abundant, and industrially viable for water splitting applications.
• Understanding the distinct active species for HER and OER enhances catalyst design.