Plasma-engineered oxygen vacancies on NiFe sulfide for highly efficient and durable oxygen evolution reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The oxygen evolution reaction (OER) is crucial for water splitting but limited by slow kinetics.
• Nickel-iron sulfides are promising OER catalysts but face challenges with insufficient active sites and poor stability.

Purpose of the Study:

• To develop a cost-effective and stable electrocatalyst for efficient OER.
• To precisely control catalyst properties using a novel surface modification strategy.

Main Methods:

• Fabrication of Fe-doped Ni3S2 nanoblocks on Ni foam (NF).
• Surface modification using O2-plasma to tune oxygen vacancy (OV) concentration.
• Electrochemical characterization in 1.0 M KOH to evaluate OER performance and stability.

Main Results:

• The p-Fe-Ni3S2/NF catalyst achieved an overpotential of 297 mV at 200 mA cm-2 with a Tafel slope of 54.87 mV dec-1.
• Demonstrated excellent stability with negligible activity decay after 100 hours of chronopotentiometric testing at 200 mA cm-2.
• Plasma modification increased active sites, electrochemically active surface area, and electron transfer kinetics.

Conclusions:

• O2-plasma modification is an effective strategy for enhancing OER electrocatalyst performance and stability.
• Precisely controlling surface oxygen vacancies offers a new pathway for designing advanced energy conversion materials.