Enabling Lattice Oxygen Participation in a Triple Perovskite Oxide Electrocatalyst for the Oxygen Evolution Reaction

Perovskite oxides are considered to be attractive catalysts for the electrocatalysis of water in an alkaline electrolyte. However, they suffer from low catalytic efficacy and stability that need to be further improved. Here we present a triple perovskite, Sr₃NiFeMoO_9−δ (SNFM), as a promising oxygen evolution electrocatalyst with high durability that outperforms double and single perovskites. The high performance of the triple perovskite SNFM could be correlated to the high lattice oxygen participation observed via pH-dependent oxygen evolution reaction (OER) activity on the reversible hydrogen electrode scale. Through the strong participation of the oxide lattice during O₂ evolution in SNFM, the kinetic limitation can be eliminated, as it occurs during the conventional adsorbate evolution mechanism. In addition to lattice oxygen participation, SNFM exhibits a low charge transfer resistance at different potentials, studied through operando electrochemical impedance spectroscopy, and a high oxygen diffusion rate that is related to its oxygen vacancy defects.