DFT calculations were performed in Quantum Espresso (QE) version 7.0 with SG15 Optimized Norm-Conserving Vanderbilt (ONCV) pseudopotentials for 13 species on Rh(111) and 2 species on Rh(211). A complete list of these species and their prior uncertainties can be found in Table . The BEEF-vdW functional was used for structure relaxations and uncertainty quantification. The molecular structures were constructed with Atomic Simulation Environment (ASE). Equation of state was used to determine the lattice constant of the Rh cell with a wave function kinetic energy cuto↵ of 60 Ry and a well-converged Monkhorst-Pack mesh of (15 ⇥ 15 ⇥ 15). The electron orbitals were broadened using the Mazari-Vanderbilt smearing method with the value of 0.01 Ry. The lattice constant was estimated as 3.85 Å, aligning well with the literature value. 3 ⇥ 3 ⇥ 4 Rh(111) and Rh(211) slabs were made with vacuum of 17 Å. The bottom 2 layers were fixed, and the top 2 layers in the slabs were relaxed by QE with a (5⇥5⇥1) k-point grid and the same energy cuto↵ and smearing conditions as used for the lattice constant calculation. The adsorbates' gas-phase counterparts were relaxed in a gamma-centered 13⇥ 13 ⇥ 13 Å3 cell until the forces fell below 0.01 eV/ Å. The functional, energy cuto↵, and the smearing methods were the same as for the slab calculations.