Electrocatalytic water oxidation by a dinuclear copper complex in a neutral aqueous solution

Area of Science:

• Inorganic Chemistry
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic water oxidation is crucial for energy conversion technologies.
• Developing robust and efficient catalysts for water oxidation remains a significant challenge.
• Dinuclear copper complexes offer promising catalytic activity but require careful ligand design for stability.

Purpose of the Study:

• To investigate the electrocatalytic water oxidation performance of a dinuclear copper(II) complex featuring the 2,7-[bis(2-pyridylmethyl)aminomethyl]-1,8-naphthyridine (BPMAN) ligand.
• To determine the reactivity and stability of the [Cu2(BPMAN)(μ-OH)](3+) complex in neutral aqueous solutions.
• To elucidate the mechanism of O-O bond formation during the catalytic cycle.

Main Methods:

• Electrochemical characterization of the copper complex.
• Water oxidation activity measurements in neutral aqueous media.
• Density Functional Theory (DFT) calculations to probe the reaction mechanism.

Main Results:

• The [Cu2(BPMAN)(μ-OH)](3+) complex demonstrated high reactivity and excellent stability during electrocatalytic water oxidation.
• Catalytic activity was observed in neutral aqueous solutions, a challenging condition for many water oxidation catalysts.
• DFT calculations indicated that O-O bond formation proceeds via an intramolecular direct coupling mechanism.

Conclusions:

• The BPMAN ligand imparts significant oxidative robustness to the dinuclear copper complex, enabling efficient water oxidation.
• The catalyst operates effectively under neutral pH conditions, broadening its applicability.
• The identified intramolecular coupling mechanism provides key insights for designing future water oxidation catalysts.