Ligand-Controlled Electrodeposition of Highly Intrinsically Active and Optically Transparent NiFeOx Hy Film as a Water Oxidation Electrocatalyst.

A highly intrinsically active and optically transparent NiFeOx Hy water oxidation catalyst was prepared by electrodeposition of [Ni(C12 -tpen)](ClO4 )2 complex (Ni-C12 ). This NiFeOx Hy film has a current density of 10 mA cm-2 with an overpotential (η) of only 298 mV at nanomolar concentration and the current density of 10 mA cm-2 remains constant over 22 h in 1 m KOH. The extremely high turnover frequency of 0.51 s-1 was obtained with η of 300 mV. More importantly, such outstanding activity and transparency (optical loss <0.5 %) of the NiFeOx Hy film are attributed to a ligand effect of the dodecyl substituent in Ni-C12 , which enables its future application in solar water splitting.