Role of Lattice Oxygen Participation in Understanding Trends in the Oxygen Evolution Reaction on Perovskites

This study demonstrates the importance of considering lattice oxygen participation in understanding trends in the oxygen evolution reaction (OER) on ABO₃ (A = lanthanum or strontium, B = transition metal) perovskites. Using density functional theory, we show that the lattice oxygen mechanism (LOM) can lead to higher OER activity than the conventional adsorbate evolving mechanism (AEM) by minimizing the thermodynamically required overpotential. We also show that the OER activity volcano for AEM is universal for all perovskites, whereas that for LOM depends on the identity of the A cation in ABO₃. This explains experimental observations that perovskites such as Pr_0.5Ba_0.5CoO_3-δ and SrCoO_3-δ show higher OER activities than the conventionally predicted optimum compounds such as LaNiO₃ and SrCoO₃. Furthermore, we show that LOM is preferred to AEM in achieving bifunctional catalysts capable of promoting both OER and ORR. Using our overall activity volcano, we finally suggest several candidate materials that are predicted to be highly active for OER via LOM.