The evolution of O2 from H2O (the oxygen evolution reaction, OER, or water oxidation catalysis, WOC) is the most sustainable anodic reaction to liberate protons and electrons that are central to fuel-forming cathodic reactions such as hydrogen evolution (HER), carbon dioxide reduction (CO2RR), and nitrogen reduction (or fixation, N2RR). Among these, the technology most prepared for widespread deployment readiness is green H2 production via coupling OER and HER in electrolysers. Acidic electrolysers can leverage the deep polymer exchange membrane (PEM) technology and benefit from the favourable HER kinetics in strong acid. The only acid OER catalysts with sufficient activity and durability for commercialization are Ir-based catalysts, for which expense and terrestrial scarcity limit scalability. Pioneering efforts in high throughput discovery of acidic OER catalysts identified optimal precious metal catalyst formulations, and in the present work we deploy these approaches to non-precious metal oxide catalysts in high dimensional composition spaces.