Spin-polarized first-principles DFT computations were performed using the Vienna ab initio Simulation Package (VASP). In this work, we used the Perdew-Burke-Ernzerhof (PBE) variety of the generalized gradient approximation (GGA) to account for exchange-correlation potential and the projector augmented wave (PAW) pseudopotential to characterize electron core interactions. Grimme's DFT-D3 technique, necessary for accounting the long-range van der Waal interactions, was used to precisely quantify the binding strength of reaction intermediates to the investigated catalytic cathode. When performing the computations on a plane-wave basis, we set the kinetic cutoff energy to 450 eV. A fivelayer slab model of the studied RuO2 (211) surface was constructed using the DFT lattice parameters obtained by bulk optimization. We used conjugate gradient method to relax the atomic geometries until the resulting force and energy were less than 0.025 eV/ and 1 x 10 -4 eV, respectively. Using a 3 x 3 x 1 Monkhorst-Pack k-point set, the first three layers were allowed to fully relax during geometric optimization. To prevent interactions across the periodic boundary, 20 Å vacuum space was implemented in the direction perpendicular to the basal plane. Brillouin zone was integrated with a broadening width of 0.05 eV using the Gaussian smearing method. The charge transfer process between the chemical intermediates and the RuO2 (211) substrate was studied via Bader charge analysis. All the studied molecular structures were visualized using VESTA software.