HCOOH* + H* → HOCHOH*, Whereas on Pd, HCOOH* adopts a non-planar configuration (Figure ). Hence, HCOOH* protonation on Pd is categorized under the RO -family of elementary steps for alcoholates, whereas on Cu, it is attributed to RCOO -protonation family. Linear fits reveal significant intercept differences, showing easier RO -protonations on Cu and easier RCOO -protonation on Pd. Note that due to limited data points, the obtained BEP correlations, in this case, are more suitable for classifying reaction steps rather than numerical estimates of activation energies, although they still yield low RMSD values of 0.10 for Cu and 0.05 for Pd. Occur via a TS akin to nucleophilic addition to carbonyls, where CH3 migrates from the metal to the carbon (yellow data in Figure ). Fewer data points were calculated for this family of elementary steps than for more abundant hydrogenation or protonation steps in the reaction network. The three data points calculated for Cu follow the same BEP relationship with an RMSD of 0.10 eV. At the same time, the correlation between the reaction and activation energies of these steps is less clear on Pd catalysts. In this case, the CH3* and CO* association is an outlier from the obtained BEP relationship, raising its RMSD to 0.36 eV (solid line in Figure ; see the structure in Figure ) from 0.13 without it (dashed line).