Correlation between Oxygen Vacancies and Oxygen Evolution Reaction Activity for a Model Electrode: PrBaCo2O5+δ. Issue 26 (17th May 2021) - Marelli, Elena
Abstract: The role of the perovskite lattice oxygen in the oxygen evolution reaction (OER) is systematically studied in the PrBaCo2 O5+δ family. The reduced number of physical/chemical variables combined with in‐depth characterizations such as neutron dif‐fraction, O K‐edge X‐ray absorption spectroscopy (XAS), electron energy loss spectroscopy (EELS), magnetization and scanning transmission electron microscopy (STEM) studies, helps investigating the complex correlation between OER activity and a single perovskite property, such as the oxygen content. Larger amount of oxygen vacancies appears to facilitate the OER, possibly contributing to the mechanism involving the oxidation of lattice oxygen, i.e., the lattice oxygen evolution reaction (LOER). Furthermore, not only the number of vacancies but also their local arrangement in the perovskite lattice influences the OER activity, with a clear drop for the more stable, ordered stoichiometry. Abstract : Oxygen vacancies content and ordering are influencing the oxygen evolution reaction activity of one of the most active perovskite electrocatalyst, PrBaCo2 O5+ δ . It is suggested that a high oxygen vacancy content in the perovskite lattice is beneficial for the activity, while lattice oxygen ordering leads to a drop in the OER activity.