To further reduce the nine-dimensional descriptor space of the three intermediates which determines the free energy landscape, we tried to find linear correlations within this space (Supplementary Fig. ). We first correlated all properties with only the CO adsorption energy ∆ CO E 0 , and got in agreement with the literature an almost perfect scaling with the *COOH formation energy ∆ COOH E 0 (R 2 = 0.90). The prediction of the *CO 2 adsorption energy in turn was significantly worse with a reduced R 2 = 0.72. Most critically, however, we found the charge sensitivity parameters ∆ i a to be not predictable using the CO adsorption energies, since no linear correlation could be identified.