Controlled-Atmosphere Corrosion Engineering Toward NiFe-LDH Enabling High-Performance Alkaline Seawater Electrolysis...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical water splitting is key for sustainable hydrogen production.
• Sluggish oxygen evolution reaction (OER) kinetics and freshwater dependence limit industrial use.
• Seawater electrolysis faces challenges from chloride ions causing corrosion and catalyst deactivation.

Purpose of the Study:

• To develop efficient and stable catalysts for oxygen evolution reaction (OER) in both freshwater and seawater.
• To improve the corrosion resistance of catalysts in chloride-rich environments.
• To enable large-scale hydrogen production from seawater.

Main Methods:

• Fabrication of sulfur-modified NiFe layered double hydroxide (S-NiFe-LDH) via a room-temperature two-step soaking strategy.
• Electrochemical characterization of catalyst performance in alkaline freshwater and seawater.
• Density Functional Theory (DFT) calculations to understand the mechanism of sulfur modification.

Main Results:

• S-NiFe-LDH demonstrated optimized electronic structure, enhanced catalytic activity, and improved charge transfer.
• The catalyst exhibited excellent OER performance with low overpotentials (250 mV at 50 mA·cm⁻²) and a Tafel slope of 22.3 mV·dec⁻¹.
• Remarkable stability (>200 h) in alkaline seawater and high Faradaic efficiency (>99%) for water splitting, suppressing chlorine evolution.

Conclusions:

• Sulfur modification enhances NiFe-LDH's intrinsic activity and corrosion resistance in seawater.
• The S-NiFe-LDH catalyst offers a scalable, energy-efficient route for industrial hydrogen production from seawater.
• This work paves the way for utilizing abundant seawater resources for sustainable hydrogen generation.