DFT calculations were performed using GPAW via the Atomic Simulation environment. All structures were generated using the AutoCat software package and were relaxed until the forces on each atom fell below a convergence criterion (<0.05 eV/ Å). The Bayesian error estimation functional with Van der Waals correlation (BEEF-vdW) was used to approximate electron-electron exchange-correlation interactions. A finite difference scheme with a target grid spacing of 0.16 Å was applied, as well as a 4×4×1 Monkhorst-Pack k-point grid for sampling the Brillouin zone of the surfaces. To improve convergence of the self-consistent field algorithm, Fermi-Dirac smearing was applied to electron occupations with a width of 0.05 eV. All adsorbates were placed on a single side of the slab, and a dipole correction was thus applied.