Probing lattice oxygen activation and coupling in metal oxides for oxygen evolution reaction catalysis

This investigation aims to probe oxygen-to-metal charge transfer and formation of oxidized oxygen species in Co- based perovskites and understand the role of these oxygen species in the catalysis of the oxygen evolution reaction (OER). Neutron powder diffraction (NPD), due to its high sensitivity to crystal symmetry and to oxygen content and position in a lattice, is therefore proposed to be a highly suitable characterization to identify reduced O‒O distances (including presence of O‒O peroxo-like dimers). Additionally, the measurements would allow to confirm charge disproportionation oxygen-to-metal charge transfer through identification of non-equivalent Co sites and an accurate band valence sum (BVS) evaluation. The knowledge to be obtained through our study would have profound fundamental importance as the first direct structural evidence for the lattice oxygen oxidation in the highly catalytically active oxides, and will be used to instruct the design of the compositions with improved oxygen evolution reaction activity through activation of the lattice oxygen sites.