Praseodymium iridium oxide as a competitive electrocatalyst for oxygen evolution reaction in acid media

Abstract

Amorphous iridium oxides (IrOx) are highly active for oxygen evolution reaction (OER) in acid media; however, it is generally unstable compared with commercial IrO2. Recently, many non-noble metal-iridium mixed oxides are prepared for catalyzing OER efficiently. Herein, we report a cubic fluorite-type praseodymium iridium oxide with the surface of IrOx (IrOx/Pr3IrO7) that shows the improved activity and stability in 0.1 mol L−1 HClO4 solution, characterized by an overpotential of 305 mV at the benchmark of 10 mA cm−2 and a small Tafel slope of 37 mV dec−1, indicating a fast reaction kinetics and a competitive activity compared with the benchmark IrO2 and most reported electrocatalysts. The initial potential increases by less than 0.07 V after continuous OER testing over 60,000 s. In contrast, IrO2 becomes nearly inactive for the OER within 20,000 s. Density functional theory calculations uncover that the optimal energy level path follows lattice oxygen mechanism (LOM). This work enlarges the family of the IrOx-type OER electrocatalyst in acid media.