# Surface Reconstruction‐Free Stability Achieving Highly Anticorrosive Seawater Splitting

## TL;DR

A new catalyst resists corrosion in seawater while efficiently splitting water for oxygen production.

## Contribution

A silver and cerium co-doped iron manganese oxide catalyst is shown to resist surface reconstruction and corrosion in seawater.

## Key findings

- The catalyst achieves 210 mV overpotential at 10 mA cm−2 in alkaline seawater.
- It maintains 99.5% faradaic efficiency for oxygen evolution.
- The electrolyzer using this catalyst operates stably for 250 hours without significant corrosion.

## Abstract

Surface reconstruction, although often associated with enhanced activity through the lattice oxygen mechanism (LOM), can expose vulnerable sites that accelerate chloride‐induced corrosion. It is demonstrated that a silver and cerium co‐doped iron manganese oxide catalyst achieves high oxygen evolution reaction (OER) activity while maintaining a stable, reconstruction‐free surface under alkaline seawater conditions. Operando X‐ray absorption spectroscopy (XAS), complemented by the previous operando Raman analysis, reveals no detectable rearrangement of chemical environment or electronic structures across the OER‐relevant potential window. The catalyst achieves a low overpotential of 210 mV to reach 10 mA cm−2 in alkaline seawater, while maintaining 99.5% faradaic efficiency for oxygen evolution. By adopting the electrocatalyst into an anion exchange membrane (AEM) electrolyzer (5×5 cm2 of active area) for direct seawater electrolysis, the durability tests show a stable electrolysis current of 5000 mA for at least 250 h, while the blank electrolyzer fails in 1 h with significant corrosion. These findings strongly support the hypothesis that inhibiting surface reconstruction can effectively enhance seawater corrosion resistance without sacrificing catalytic performance.

The complex metal oxides of AgCe‐FeMnOH can achieve an excellent oxygen evolution (OER) activity while maintaining its stability under alkaline seawater electrolysis. The surface reconstruction‐free behaviors lead to the durable seawater corrosion resistance without compromising the catalytic activities.