Seawater Electrolysis Sustained via the Permselective Layer on Catalysts

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Seawater electrolysis offers a sustainable route to green hydrogen.
• Anode stability against chlorine corrosion and side reactions is crucial for efficient seawater electrolysis.
• Nickel-iron molybdate microrods show promise but require enhanced durability.

Purpose of the Study:

• To develop a robust anode for alkaline seawater electrolysis resistant to chlorine corrosion.
• To investigate the mechanism of chloride ion repulsion and hydroxyl diffusion.
• To demonstrate the long-term stability and efficiency of the developed anode.

Main Methods:

• Designing a conformal phosphate coating on nickel-iron molybdate microrods.
• Investigating the ion-selective permeable layer's properties.
• Conducting long-term stability tests at high current densities (1 A cm⁻²).
• Evaluating performance in an actual electrolyzer at 0.5 A cm⁻².

Main Results:

• The phosphate coating effectively repels chloride ions and facilitates hydroxyl diffusion.
• The phosphated anode demonstrated stable alkaline seawater oxidation for over 700 hours at 1 A cm⁻² without corrosion.
• Seawater electrolysis in an electrolyzer achieved 500 hours of stability at 0.5 A cm⁻², 2.0 V, with 74% cell efficiency.

Conclusions:

• The developed surface-phosphated microrod anode is highly effective for stable and efficient green hydrogen production from seawater.
• This innovation addresses key challenges in seawater electrolysis, paving the way for large-scale green hydrogen generation.