Remarkable Oxygen-Evolution Activity of a Perovskite Oxide from the Ca2-xSrxFe2O6- Series

Herein in we report the unprecedented catalytic activity of an iron-based oxygen-deficient perovskite for the oxygen-evolution reaction (OER). The systematic trends in OER activity as a function of composition, defect-order, and electrical conductivity have been demonstrated, leading to a methodical increase in OER catalytic activity: Ca2Fe2O6-<CaSrFe2O6-<Sr2Fe2O6-. Sr2Fe2O6- also has the highest electrical conductivity and a unique type of defect-order. In conventional experiments using glassy carbon electrode, Sr2Fe2O6- shows better OER activity than the current state of the art catalysts, Ba0.5Sr0.5Co0.8Fe0.2O3- and RuO2. It also offers a high intrinsic electrical conductivity, which allows it to act as a catalyst without the need for glassy carbon electrode or carbon powder. Pure disks of this material exhibit an outstanding activity for OER, without any additives or need for electrode preparation.