Facile surface defect engineering on perovskite oxides for enhanced OER performance.

Perovskite oxides have been considered as potential alternative electrocatalysts in the oxygen evolution reaction (OER) field. In this work, a sequence of excellent OER perovskite catalysts was obtained by immersing Sr 2 CoFeO 6 in a diluted HNO 3 solution. Therein, the 24 h etched Sr 2 CoFeO 6 sample (SCFO-24) exhibits the best OER activity, with an overpotential of 300 mV at 10 mA cm -2 and a Tafel slope of 59.62 mV dec -1 . The improved OER activity of SCFO-24 can be attributed to the enhanced specific surface area derived from selective dissolution of a large amount of Sr and the high ratio of oxidative oxygen species (O 2- /O - ). Our work promotes this simple but efficient approach to improving the OER performance of perovskite oxides.