Tuning the Oxygen Reduction Reactivity of Layered Perovskites Using the Jahn-Teller Effect.

Compositional tuning of layered perovskite oxides provides a means of systematically studying how local distortions affect fundamental aspects of electrochemical reaction pathways. Structural analysis of a family of samples LaSrNiCoO shows that Ni-rich compositions have an expanded crystalline axis, which is anisotropically compressed by systematic Co incorporation. Raman spectra reveal the strong growth of a symmetry forbidden mode, which suggests that Co acts through localized distortions.