where * refers to an adsorption site on the bare graphene and Pt substrates. In order to avoid calculating the free energy of solution species, the limiting potential for the adsorption step can be calculated using the computational Cu electrode reference, which is given by: Δ𝐺 𝐶𝑢 2+ + Δ𝐺 2𝑒 -(𝑈=0) = Δ𝐺 𝐶𝑢 . The adsorption energy (𝐸 𝑎𝑑𝑠 𝜃 ) then can be described as: