Ligand assisted electrocatalytic water oxidation by a copper(ii) complex in neutral phosphate buffer

Area of Science:

• Inorganic Chemistry
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic water oxidation is crucial for renewable energy technologies.
• Developing efficient and stable catalysts is a key challenge.
• Copper complexes offer potential due to their redox properties.

Purpose of the Study:

• To investigate the electrocatalytic water oxidation activity of a novel copper(II) complex.
• To understand the catalytic mechanism, particularly the role of the ligand.
• To assess the efficiency and performance of the complex as a water oxidation catalyst.

Main Methods:

• Synthesis and characterization of the copper(II) complex [Cu(L1H)(L1)(OH2)](ClO4).
• Electrochemical studies including cyclic voltammetry and chronoamperometry in neutral phosphate buffer.
• Analysis of catalytic activity, turnover frequency, and faradaic efficiency.

Main Results:

• The copper(II) complex exhibits high electrocatalytic water oxidation activity.
• A turnover frequency of approximately 100 s-1 was achieved at a 675 mV overpotential.
• Faradaic efficiency was measured at approximately 94%, indicating efficient electron utilization.
• Electrochemical analysis suggests a proton-coupled electron transfer (PCET) step involving the aryl oxime ligand.

Conclusions:

• The copper(II) complex is a highly efficient electrocatalyst for water oxidation.
• The aryl oxime ligand plays a critical role in the catalytic mechanism via PCET.
• This mechanism facilitates the accumulation of high oxidizing equivalents at the catalytic center.