An iron-based thin film as a highly efficient catalyst for electrochemical water oxidation in a carbonate electrolyte.

A highly active iron-based water-oxidation catalyst was electrodeposited from a CO2 saturated bicarbonate solution containing Fe(2+). This catalyst (Fe-Ci) produces a current density of 10 mA cm(-2) at an overpotential of 560 mV and the activity remains constant over 18 h in the environmentally benign HCO3(-)/CO3(2-) buffer (pH 9.75). A Tafel slope of 34 mV dec(-1) was obtained for Fe-Ci, which is lower than other reported values for iron-based catalysts.