In the final step of this workflow, the catalytic activity of each of these 290 spinel oxide materials is predicted by calculating the theoretical overpotential using the computational hydrogen electrode method proposed by Nørskov and coworkers . The computational hydrogen electrode states that the chemical potential of the proton and electron pairs can be described as half of the chemical potential of the H2 molecule since these species are in chemical equilibrium at 0V vs the reversible hydrogen electrode (RHE) . We can use this model to estimate the Gibbs free energies of the first two reaction steps of the adsorbate evolution mechanism (AEM) by calculating the binding energies of the *O, *OH and *OOH intermediates of OER. To calculate these energies, we created slabs of each material, relaxed the surface of the slabs, and then added the relaxed *O, *OH and *OOH molecules on top of the metal sites of the slab surface. All possible slab surfaces with a maximum absolute Miller index of one were first created using Pymatgen . Higher index surfaces were not included in this step to keep the computational cost reasonable. The surface energies of all these slabs were calculated and the slab with the lowest surface energy was identified. Next, *O, *OH and *OOH molecules were fixed onto the surface of the slab with the lowest surface energy. Each of these slabs has a 50% monolayer coverage of *O, *OH and *OOH intermediates respectively. This assumption was made in order to limit computational cost that could come with considering all the different permutations of intermediates possible. We note that surface coverages can change depending on the applied potential, and that the potential window of the stability of surface coverage should be taken into account in future studies where the predicted overpotential of catalysts is computationally assessed. The adsorption energy of each of these intermediates was calculated and used to determine the theoretical overpotential of OER on the surface of each material.