where 𝜃 is the coverage factor, Δ𝐺 𝐶𝑢 * is the Gibbs free energy of the Cu adatom and Δ𝐺 𝐶𝑢 is the Gibbs free energy of the bulk Cu. We approximate the free energies to be equal to their DFT energies, neglecting entropic contributions: ). In addition, all low index surfaces of Pt are considered for the calculation. The procedure to determine the lowest adsorption energy site is described in the Method section. A decrease of adsorption energy from low to high coverage can be observed across all the systems studied in the top plot of Figure , indicating that the Cu adatom will adsorb on Pt and graphene surface after overcoming the initial nucleation overpotential.