A Universal AgP₂ Nanowire Modification Method Enabling Durable Anodes for Alkaline Seawater Electrolysis

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Alkaline seawater electrolysis offers a sustainable hydrogen production pathway.
• High chloride ion concentration in seawater leads to severe anode corrosion, limiting operational stability.

Purpose of the Study:

• To develop a scalable and universal method for creating corrosion-resistant oxygen-evolution anodes for alkaline seawater electrolysis.
• To enhance the long-term stability and efficiency of electrodes in highly saline alkaline environments.

Main Methods:

• Loading silver nanowires onto various anode platforms (Ni mesh, NiFe-LDH/Ni mesh, NiCo-LDH/Ni mesh) followed by phosphating treatment.
• In situ conversion of silver nanowires to a silver chloride network and phosphate adsorption to form a protective layer.
• Electrochemical testing in high salinity alkaline electrolytes and performance evaluation in a scaled-up alkaline seawater electrolyzer.

Main Results:

• The modified anodes, particularly NiFeP@AgP2 NWs, demonstrated remarkable stability, operating over 600 hours in highly saline alkaline electrolyte and over 1000 hours in 1 M NaOH + 0.5 M NaCl.
• A protective layer formed by a silver chloride network and adsorbed phosphate ions effectively immobilized chloride ions and repelled free chloride, suppressing corrosion.
• Scaled-up electrodes (approx. 100 cm²) exhibited stable operation in an alkaline seawater electrolyzer with low energy consumption.

Conclusions:

• The proposed silver nanowire loading and phosphating method provides a robust strategy for fabricating highly corrosion-resistant oxygen-evolution anodes.
• This advancement significantly improves the durability of electrodes for alkaline seawater electrolysis, paving the way for efficient and sustainable hydrogen production.
• The developed technology demonstrates practical applicability for large-scale hydrogen generation using seawater as an electrolyte.