Impact of the hybridization form of the coordinated nitrogen atom on the electrocatalytic water oxidation performance of copper complexes with pentadentate amine-pyridine ligands.

The field of molecular catalysts places a strong emphasis on the connection between the ligand structure and its catalytic performance. Herein, we changed the type of coordinated nitrogen atom in pentadentate amine-pyridine ligands to explore the impact of its hybridization form on the water oxidation performance of copper complexes. In the electrochemical tests, the copper complex bearing dipyridine-triamine displayed an apparently higher rate constant of 4.97 s-1, while the copper complex with tripyridine-diamine demonstrated overpotential reduction by 56 mV and better long-term electrolytic stability.

A low-cost commercial Cu(II)-EDTA complex for electrocatalytic water oxidation in neutral aqueous solution.

Herein, we choose a commercial Cu complex [Cu(EDTA)(H2O)] (EDTA = ethylene diamine tetraacetic acid) as a molecular catalyst for water oxidation to avoid complex synthesis and lower catalyst cost. [Cu(EDTA)(H2O)] could catalyze the water oxidation reaction efficiently under neutral conditions with an overpotential of 684 mV, a kcat of 8.03 s-1 and good stability in the long-term electrolysis. Our finding is of great significance for the development of stable, rapid, and easily accessible catalysts for water oxidation.