South Korean-based researchers have used first-principles quantum mechanical simulations to better understand the structure-property relationships in various polymorphic phases of iridium oxides to elucidate their outstanding performance in catalyzing the oxygen evolution reaction (OER). The OER is an important half-cell reaction where water is catalytically split to evolve oxygen. However, due to the intrinsic sluggish kinetics of the OER, this leads to an overall poor catalytic performance in general.