CO induced phase-segregation to construct robust and efficient IrRux@Ir core-shell electrocatalyst towards acidic oxygen evolution

The development of highly active and durable electrocatalysts towards oxygen evolution reaction (OER) in acidic solution is essential for the commercialization of proton exchange membrane water electrolysis (PEMWE). Herein, we design a rational CO-induced phase-segregation strategy to efficient construction of core-shell structure electrocatalyst featured with IrRux core and Ir-rich shell (IrRux@Ir). X-ray photoelectron spectroscopy reveals that the intensive electronic interaction between IrRux core and Ir-rich shell induces the charge transfer from Ir to IrRux, thereby increasing the oxidation state of surface Ir sites and leading to an enhanced OER activity. Simultaneously, the Ir-rich shell efficiently protects the inner Ru atoms against dissolution during the long-term electrolysis, in turn significantly improving the structural stability. The resultant IrRux@Ir catalyst exhibits a low overpotential of ca. 288 mV at a current density of 10 mAcm−2 and desirable durability. Impressively, the membrane electrode assembly integrated with IrRux@Ir as anode maintains a steady value of approximately 1.83 ± 0.02 V during 400 h of electrolysis at a current density of 1 A cm−2, demonstrating that the IrRux@Ir is one of the most robust OER electrocatalyst to date. This study provides a new perspective to design high performance and robust OER electrocatalysts in PEMWE.