Activating Inert, Nonprecious Perovskites with Iridium Dopants for Efficient Oxygen Evolution Reaction under Acidic Conditions.

Simultaneous realization of improved activity, enhanced stability, and reduced cost remains a desirable yet challenging goal in the search of oxygen evolution electrocatalysts in acid. Herein we report iridium-containing strontium titanates (Ir-STO) as active and stable, low-iridium perovskite electrocatalysts for the oxygen evolution reaction (OER) in acid. The Ir-STO contains 57 wt % less iridium relative to the benchmark catalyst IrO2 , but it exhibits more than 10 times higher catalytic activity for OER. It is shown to be among the most efficient iridium-based oxide electrocatalysts for OER in acid. Theoretical results reveal that the incorporation of iridium dopants in the STO matrix activates the intrinsically inert titanium sites, strengthening the surface oxygen adsorption on titanium sites and thereby giving nonprecious titanium catalytic sites that have activities close to or even better than iridium sites.