Geometry optimization, energy calculations, and vibrational analysis of CO/Pt(111) were conducted using density functional theory (DFT). The QUANTUM ESPRESSO code was used in Atomic Simulation Environment (ASE) . The PBE exchange-correlation functional was employed and Grimme's D3 corrections along with the three-body Axilrod-Teller-Muto corrections were applied. Plane-wave kinetic energy cutoff was 60 Ry. A periodic unit cell of 3 × 3 and four layers with an experimental lattice constant of 3.92 Å was adopted to represent the Pt(111) surface. The bottom two layers were fixed, and a vacuum layer of 10.0 Å was applied above and underneath the Pt layers. A (4×4×1) k-point grid was used. Model structures were optimized with a Quasi-Newton algorithm with a force convergence criteria of 0.05 eV/ Å. CO * diffusion barrier energy was calculated with the dynamic nudged elastic band (dyNEB) and climbing image (CI) method , both with convergence criteria of 0.05 eV/ Å.