Surface modified perovskite SrCo0.8Fe0.1Nb0.1O3-δ oxide for enhanced electrocatalytic activity of oxygen evolution reaction

• Simple acid etching modification treatment of SCFN surface. • The resulting A-site defects and oxygen vacancies increase OER activity. • The overpotential of SCFN-60 was decreased by 70 mV after acid treatment. It is of great significance to develop efficient and inexpensive electrocatalysts for reducing the overpotential of oxygen evolution reaction (OER). The surface of catalysts always plays an important role in catalytic reactions. Herein, we report the improvement of catalytic performance of a perovskite SrCo 0.8 Fe 0.1 Nb 0.1 O 3-δ (SCFN) by simple surface treatment with dilute nitric acid. It was found that the acid treatment could partially dissolve the A-site cation of Sr, increase the oxygen vacancy concentration and change the oxidation state of the B-site transition metal. Moreover, the modification method also increased the hydroxide adsorption capacity and concentrations of active oxide species. The OER activity and stability of HNO 3 treated sample of SCFN-60 were remarkably improved, and the overpotential was significantly reduced to 360 mV (0.1 M KOH). This work provides a simple strategy for increasing the OER activity of perovskite oxides in an alkaline solution at room temperature.