Iridium‐Incorporated Strontium Hafnate as Efficient Electrocatalysts for Water Splitting in Acid and Alkaline Electrolytes

Developing high‐performance, durable, yet low‐iridium (Ir) catalysts presents a significant hurdle in the region of water splitting. Herein, Ir‐incorporated strontium hafnates were explored as electrocatalysts for hydrogen evolution reactions (HER) and oxygen evolution reactions (OER) in acidic and alkaline electrolytes. The results of spectroscopies reveal an increase in oxygen vacancy and electron density around Hf atoms of SHO after incorporating Ir atoms. The SHIO‐0.4 possesses a Tafel slope of Tafel slopes of 66 mV dec −1 and an overpotential of 240 mV to acquire a current density of 10 mA cm −2 toward OER in 0.5 M H 2 SO 4 . In situ electrochemical measurements, combined with theoretical calculations, display the enhanced participation of oxygen vacancies (O v ) in SHIO. Hence, the high OER performance of SHIO is attributed to the mechanism via lattice oxygen and reconstructed Ir‐based oxides at the surface. This work unveils the effect of Ir atoms on the electrochemical performance of SHO, which paves the way for fabricating efficient perovskite‐based catalysts for water splitting.