Ir-IrO2 with heterogeneous interfaces and oxygen vacancies-rich surfaces for highly efficient oxygen evolution reaction

The development of efficient and stable catalysts for oxygen evolution reaction (OER) has recently attracted much attention, and the major challenge of current research is to offer fast kinetics and enhance the durability in a harsh oxidising environment. Herein, an effective strategy is developed to construct a unique heterogeneous interface between Ir nanoclusters and IrO2 via a facile and scalable chemical reduction method, followed by the thermal treatment under Ar atmosphere. Both the transmission electron microscope and X-ray photoelectron spectroscopy results revealed that the as-prepared Ir-IrO2 has been engineered with heterogeneous interfaces and oxygen vacancies-rich surfaces. Benefited from newly-formed active surfaces and the oxygen vacancies-rich surfaces, the Ir-IrO2 catalyst exhibits increased catalytic active sites and enhanced catalytic activity towards the OER compared with the pure IrO2 and commercial IrO2. The over-potential of the Ir-IrO2 is ca. 329 mV at 10 mA cm(-2), and the mass activity is ca. 1851 A (1)(gIrO2-) at 1.60 V (vs. RHE), about 2.4 times that of the commercial IrO2 (ca. 779 A (-1)(gIrO2) ). In addition, both the improved catalytic performance and durability for the OER is further confirmed in PEM water electrolysis cell.