The reaction proceeds trough the deprotonation of an interface methanol molecule, followed by the concerted formation of one -H and one -OCH 3 bond with Graphene in a para configuration (Panel a). Inspection of the metadynamics bias (Panel b) suggests a huge free energy barrier, possibly of ca. 1060 kJ/mol, based on the bias accumulated in the initial minimum (reactant basin) until the onset of the transformation. Note that this provides only a rough (over)estimation of the free-energy barrier: a more precise estimation of the barrier, as well as of the corresponding kinetic rate, would require i) the use of an optimal reaction coordinate, and ii) the analysis of a bias displaying steady evolution, achievable only by simulating a trajectory long-enough to display many forward and backward reactions. Both conditions are, unfortunately, impossible to meet in this specific system due to the high cost of ab initio MD on our relatively large model.