Density functional theory calculations were carried out using Quantum ESPRESSO. Core electrons were treated using pseudopotentials from the SSSP Precision pseudopotential database. Valence electrons were described using plane-waves with kinetic energy and density cutoffs of at least 80 Ry and 600 Ry respectively. In cases where the recommended cutoffs are greater that these values, the larger of the two is used. Gaussian smearing of width 0.0075 Ry (≈ 0.1 eV) was used for all calculations. A k-point mesh of (4, 4, 1) was used for all surface calculations. The PBE functional was used to describe exchange and correlation effects. Calculations were considered converged if the maximum force on each atom was less than 10 -4 Ry Bohr -1 and the energy difference between successive SCF cycles is less than 2 • 10 -5 Ry. All calculations were performed without spin polarisation. Structures were prepared using the Atomic Simulation Environment. The adsorbate was initially placed at symmetrically inequivalent sites at the start of the relaxation. It is found that adsorbates at the hollow site for all metals have the lowest energy. Provenance of each calculation in this work was stored using AiiDA 37 and performed using the AiiDA quantumespresso plugin.