Aromaticity Driven Electrocatalytic Water Oxidation by a Phosphorus-Nitrogen PN3-Pincer Cobalt Complex

27 August 2019, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Water oxidation is the primary step in both natural and artificial photosynthesis to convert solar energy in into chemical fuels. Herein, we report the first cobalt-based pincer catalyst for electrolytic water oxidation at neutral pH with high efficiency under electrochemical conditions. Most importantly, ligand (pseudo)aromaticity is identified to play an important role in the electrocatalysis. A significant potential jump (~300 mV) was achieved towards a lower positive value when the aromatized cobalt complex was transformed to a (pseudo)dearomatized cobalt species. This complex catalyzes the water oxidation in its high valent oxidation state at a much lower overpotential (~ 340 mV vs. NHE) based on the onset potential (0.5 mA/cm2) of catalysis at pH 10.5, outperforming all the other literature systems. These observations may provide a new strategy for the design of earth-abundant transition metal-based water oxidation catalysts.


Cobalt-Pincer Complex
Water Oxidation


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