fig2
Figure 2. Gibbs free energy of H adsorption (ΔG*H) at different sites on MN4-gra/MMN6-gra/M1M2N6-gra. For the non-metal sites, only the values with the strongest adsorption are shown. Carbon: brown; Iron: golden; Cobalt: dark blue; Nickel: silvery; Nitrogen: light blue.
