First-Principles Simulation of the Active Sites and Reaction Environment in Electrocatalysis - Fuel Cell Catalysis: A Surface Science Approach - page 108

Figure 4.8 Potential-dependent reaction energies for water dissociation to form OH, O, and H
over Pt(111). (a) Energy curves based on the full charge model: the nonlinearity of these plots
expresses the capacitance of the interface. (b) Differences of the curves indicate the reaction
energies. The nonlinear terms cancel almost completely. The dashed lines indicate predictions
made from the linear model, whereas the solid lines are predictions made from a full solvation/
charge-based model [Rossmeisl et al., 2006].
reaction energy. This holds only when the adsorbed reactant and product states
have similar dipole moments, similar solvation structures, and similar effects on the
interfacial capacitance. This similarity does not hold, however, when comparing,
for example, the adsorption of molecular oxygen compared with water at the electri-
fied interface. This competitive adsorption process is discussed in the following
section.