Fe(III) Docking-Activated Sites in Layered Birnessite for Efficient Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient water splitting requires catalysts for the oxygen evolution reaction (OER).
• Birnessite shows structural similarity to natural oxygen-evolving complexes but has limited catalytic activity.
• Non-noble metal catalysts are crucial for sustainable hydrogen production.

Purpose of the Study:

• To develop a highly active non-noble metal catalyst for OER.
• To investigate the mechanism behind enhanced catalytic activity in engineered birnessite.

Main Methods:

• Controlled Fe(III) intercalation and docking for layer reconstruction.
• Electrochemical characterizations (overpotential, Tafel slope).
• Experimental characterizations, molecular dynamics simulations, and DFT calculations.

Main Results:

• A novel Fe-Birnessite (Fe-Bir) catalyst was synthesized.
• Fe-Bir achieved a low OER overpotential (240 mV at 10 mA/cm²) and Tafel slope (33 mV/dec).
• The catalyst exhibits active Fe(III)-O-Mn(III) centers and an engineered interlayer environment.

Conclusions:

• Fe-Bir demonstrates superior OER performance, outperforming other birnessite-based catalysts.
• Synergistic effects between Fe and Mn sites and optimized water ordering are key to high activity.
• Engineering the interlayer environment of layered materials is a promising strategy for efficient energy conversion catalysis.