NiFe oxyhydroxide is a highly active electrocatalyst for the oxygen evolution reaction, a crucial process for carbon-neutral energy storage. Quantum chemical calculations have confirmed the operando Mössbauer spectroscopic identification of Fe(IV) sites in the material. However, the nature of the catalytically active site—the metal site, its oxidation state, and its coordination—has yet to be determined with the same rigor. Zachary Goldsmith will use Blue Waters to perform electronic structure calculations of Ni(Fe) oxyhydroxide edges in concert with in situ spectroscopy to elucidate the chemical and electronic environments most conducive to facilitating catalysis. This work will push the boundaries of modeling reactive interfaces and establish novel catalyst design principles.