First-Principles Simulation of the Active Sites and Reaction Environment in Electrocatalysis - Fuel Cell Catalysis: A Surface Science Approach - page 121

Figure 4.14 Free energy as a function of electrode potential for the species considered in the
reduction of O 2 to form OOH . In the atomistic diagrams, purple coloring is used to illustrate
where the electron involved in reduction resides in each species. (See color insert.)
Figure 4.15 Overall barrier for O 2 reduction to OOH over the Pt(111) surface as a function
of electrode potential. The inset shows the transition state for reduction at 1 V/NHE.