Activation pathways taking place at molecular copper precatalysts for the oxygen evolution reaction

The activation processes of [Cu II (bdmpza) 2 ] in the water oxidation reaction were investigated using cyclic voltammetry and chronoamperometry. Two different paths wherein CuO is formed were distinguished. [Cu II (bdmpza) 2 ] can be oxidized at high potentials to form CuO, which was observed by a slight increase in catalytic current over time. When [Cu II (bdmpza) 2 ] is initially reduced at low potentials, a more active water oxidation catalyst is generated, yielding high catalytic currents from the moment a sufficient potential is applied. This work highlights the importance of catalyst pre-treatment and the choice of the experimental conditions in water oxidation catalysis using copper complexes.