Identifying and tuning coordinated water molecules for efficient electrocatalytic water oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Coordination complexes show potential for electrocatalytic oxygen evolution reaction (OER).
• Challenges exist in optimizing kinetics through local coordination regulation.
• Developing stable and efficient OER electrocatalysts is crucial for energy applications.

Purpose of the Study:

• To tailor coordination complexes with refined synergy of carboxylate anions and multiconjugated benzimidazole ligands.
• To investigate the role of coordinated water molecules in OER kinetics and mechanism.
• To achieve efficient and stable electrocatalytic oxygen evolution.

Main Methods:

• Synthesis of well-defined coordination complexes with 3D supramolecular/coordinated structures.
• In situ experiments to probe reaction intermediates and mechanisms.
• Theory simulations to understand thermodynamic energy barriers and reaction pathways.

Main Results:

• Coordination complexes with integrated coordinated water molecules were successfully synthesized.
• Coordinated water acts as active sites, facilitating OER via an intramolecular oxygen coupling mechanism.
• Achieved a low overpotential of 248 mV at 10 mA cm⁻² and 200 hours of stability.

Conclusions:

• Crafting coordinated water molecules is a promising strategy for efficient electrocatalysis.
• The intramolecular oxygen coupling mechanism is favored by the presence of coordinated water.
• The developed complexes offer a new avenue for designing advanced electrocatalysts for OER.