with the surface charge density σ, the electrode potential vs. SHE U , the zero-point energy and finite temperature correction term ∆ i E T,S,ZPE,• , the gap or Helmholtz capacitance C gap and the potential of zero charge (PZC) U PZC . ∆ i E(σ(U )) is the DFT calculated expression, the surface-charge dependent adsorption energy of a specific reaction intermediate relative to the bare slab and CO 2 (g) (in the case of * COOH and * CO 2 ) or CO(g) (in the case of * CO). Within DFT, the effect of surface charge was included by means of an implicit solvation model and planar counter charge approach. From this we found a roughly linear relation ∆ i E(σ(U )) (corresponding to a constant capacitance during adsorption )