Surface Reconstruction-Free Stability Achieving Highly Anticorrosive Seawater Splitting.

Area of Science:

• Electrochemistry
• Materials Science
• Corrosion Science

Background:

• Surface reconstruction in catalysts can improve activity but also lead to corrosion, especially in harsh environments like seawater.
• Chloride-induced corrosion is a major challenge for catalysts used in seawater electrolysis.
• Developing stable electrocatalysts for oxygen evolution reaction (OER) in alkaline seawater is crucial for energy applications.

Purpose of the Study:

• To develop a catalyst that exhibits high OER activity while maintaining a stable, reconstruction-free surface in alkaline seawater.
• To investigate the effect of inhibiting surface reconstruction on corrosion resistance and catalytic performance.
• To demonstrate the practical application of such a catalyst in direct seawater electrolysis.

Main Methods:

• Synthesis of a silver and cerium co-doped iron manganese oxide catalyst.
• Electrochemical characterization including OER activity and faradaic efficiency measurements in alkaline seawater.
• Operando X-ray absorption spectroscopy (XAS) and operando Raman spectroscopy to probe surface stability.
• Durability testing of the catalyst in an anion exchange membrane (AEM) electrolyzer for direct seawater electrolysis.

Main Results:

• The co-doped catalyst achieved high OER activity with a low overpotential (210 mV at 10 mA cm⁻²) and high faradaic efficiency (99.5%).
• Operando XAS and Raman analyses confirmed a stable, reconstruction-free surface under OER conditions in alkaline seawater.
• The catalyst demonstrated exceptional durability in a 5×5 cm² AEM electrolyzer, maintaining a stable current for over 250 hours, unlike a blank electrolyzer which failed within 1 hour due to corrosion.
• The catalyst exhibited significantly enhanced resistance to chloride-induced corrosion.

Conclusions:

• Inhibiting surface reconstruction is an effective strategy to enhance the seawater corrosion resistance of electrocatalysts.
• The silver and cerium co-doped iron manganese oxide catalyst offers a promising solution for stable and efficient direct seawater electrolysis.
• This work provides a new pathway for designing robust electrocatalysts for harsh electrochemical environments.