This study focuses on the dynamics of CO formation on Pt(111). To this end, a new semiempirical interaction potential was derived by using much of the most recent experimental information obtained from CO chemisorbed on the on top and bridge platinum sites. The dynamics on the adiabatic potential surface has been performed according to the semiclassical collisional method developed for molecule-surface interactions. The role played by the multiphonon excitation mechanism, the adsorption site, and the surface temperature effects on the Eley-Rideal recombination dynamics and on the energy fluxes through the platinum surface and the internal states of the formed CO molecules was studied in detail.