In Situ Microenvironment Engineering Enables Synergistic Suppression of Protons and Chloride for Durable Seawater...

Area of Science:

• Electrochemistry
• Materials Science
• Renewable Energy

Background:

• Direct seawater electrolysis is a sustainable hydrogen production method.
• Industrial application is limited by catalyst deactivation and corrosion due to local acidification and chloride ions at high current densities.

Purpose of the Study:

• To develop a catalyst for stable alkaline seawater oxidation (ASO) under industrial-level current densities.
• To investigate the mechanism behind catalyst stabilization in a challenging seawater environment.

Main Methods:

• Synthesis of a novel NiS₂/Cr₂S₃/NF catalyst.
• Long-term stability testing of the catalyst in ASO at high current densities (1-2 A cm⁻²).
• Integration into an anion exchange membrane water electrolysis device.
• Mechanistic studies using electrochemical analysis.

Main Results:

• The NiS₂/Cr₂S₃/NF catalyst demonstrated stable ASO for over 3000 hours at 1 A cm⁻² and 800 hours at 2 A cm⁻².
• The catalyst maintained durability exceeding 600 hours at 1 A cm⁻² in a practical electrolysis device.
• Mechanistic studies revealed synergistic effects stabilizing an alkaline anodic microenvironment, suppressing chlorine evolution and acidification.

Conclusions:

• The developed catalyst provides a viable strategy for efficient and stable direct seawater electrolysis.
• This advancement contributes to large-scale hydrogen production powered by renewable energy.