(ii) 15×9 graphene supercells are generated by embedding carbon atoms into the graphene from the previous step (See Fig. ), (iii) While the atoms from step (i) are frozen, the geometry of the added carbon atoms from step (ii) is optimized using DFT. The implicit SCCS solvation model with the dielectric constant of water is applied to the entire supercell for further calculations. Now all the Marcus parameters can be recalculated for an electrode with nearly constant potential (tabulated in Table ). Qualitatively, Fig. (b) and (c) show a systematic increase and decrease in the ∆A 0 IJ and λ values, respectively. Consequently, activation barriers rise, which results in slower kinetics. For the larger supercell the electronic couplings slightly reduce due to a more delocalized net charge compared to the surface of 7×4 graphene supercell.