Surface Activation and Ni-S Stabilization in NiO/NiS₂ for Efficient Oxygen Evolution Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient and stable electrocatalysts for the oxygen evolution reaction (OER) is crucial for energy conversion technologies.
• Sulfur-containing catalysts often face challenges with structural stabilization and active species manipulation during OER.
• Corrosion of metal-sulfur bonds is a significant limiting factor for the long-term durability of these catalysts.

Purpose of the Study:

• To investigate the effect of iron (Fe) doping on the structural stabilization and OER activity of NiO/NiS2 catalysts.
• To understand the mechanism by which Fe doping influences the formation of active species and mitigates catalyst corrosion.
• To evaluate the long-term durability of Fe-doped catalysts in the OER process.

Main Methods:

• Synthesis of NiO/NiS2 and Fe-doped Fe-NiO/NiS2 catalyst models.
• Electrochemical characterization, including overpotential measurements at a current density of 10 mA cm⁻².
• Analysis of surface hydroxyl group accumulation and investigation of metal-sulfur (M-S) bond corrosion mechanisms.

Main Results:

• Fe-NiO/NiS2 demonstrated a significantly low OER overpotential of 270 mV at 10 mA cm⁻².
• Fe doping promoted the formation of highly active nickel oxyhydroxide (NiOOH) species by increasing surface hydroxyl groups.
• Bulk Fe doping acted as a sacrificial agent, alleviating the oxidation corrosion of Ni-S bonds and enhancing catalyst durability.

Conclusions:

• Fe doping is an effective strategy to improve both the activity and long-term stability of NiS2-based OER electrocatalysts.
• The sacrificial role of bulk Fe in preventing sulfur corrosion is key to achieving enhanced durability.
• This study highlights the importance of addressing sulfur corrosion in sulfur-containing materials for advanced electrocatalysis.