Overcoming the Activity-Stability Trade-Off in Electrocatalysts via Unconventional Two-Step Structural...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Lattice oxygen activation via structural reconstruction is key for oxide catalysts in redox systems.
• Understanding pre-electrochemical reconstruction transformations and their effect on structural inhomogeneity is crucial for oxygen evolution reactions.

Purpose of the Study:

• To investigate the structural transformations and lattice oxygen activation in W-doped Co-Fe amorphous oxide during electrochemical oxygen evolution.
• To elucidate the relationship between structural inhomogeneity, chemical state evolution, and catalytic performance.

Main Methods:

• Spontaneous and electrochemical bulk reconstructions of W-doped Co-Fe amorphous oxide.
• In situ spectroscopic techniques (e.g., X-ray absorption spectroscopy, Raman spectroscopy) to monitor changes.
• Electrochemical measurements to assess catalytic performance and stability.

Main Results:

• Reconstruction yields an active γ-layered double hydroxide (LDH) with local structural inhomogeneity.
• The reconstructed catalyst forms reactive nonbonding oxygen states, enabling Co3+-catalyzed O2 evolution.
• Achieved a cell voltage of 1.69 V at 1 A cm-2 with 600 h stability in anion-exchange membrane water electrolyzers.

Conclusions:

• The study provides the first experimental evidence of a potential-dependent mechanistic transition in electrocatalysts.
• Deepened understanding of structure-performance relationships and the role of chemical state evolution in catalysis.
• Highlights the importance of controlled structural reconstruction for advanced electrocatalyst design.