eV, with or without added carbon atoms. The Pt atoms near Ge are generally more negatively charged in both Pt4 and Pt7 (Fig. ) based clusters. Thus, on the one hand, -bonding can be diminished. On the other hand, the increased negative charge could lead to enhanced π-back-donation strengthening CO binding. However, when Pt is bound to Ge in a polar covalent manner, its d-states downshift and the ability to -back-donate is also reduced, as can be seen from the COHP analysis presented in the SI correspond to desorption energies between ~0.5 and 1.1 eV, while higher temperature peak would correspond to desorption energies around 1.3 eV. Thus, while DFT appears to have significantly overestimated the CO binding energies, it suggests a tentative assignment of the low temperature desorption to CO bound to Pt atoms proximal to Ge, and the high temperature peak to CO at Pt atoms distal to Ge. This 2x scaling is attributed to the well-known CO over-binding problem in DFT, and the lack of entropic contributions in the model.