Effect of surface hydroxyl coverage on platinum nanoparticles in the oxygen reduction reaction: All-electron density functional theory analysis

Catalysts in commercial proton exchange membrane fuel cells must be optimized for activity and cost, but improvements are hampered for Pt nanoparticles by low activity resulting from extensive OH adsorption. A model system clearly elucidating the impact of OH coverage on Pt nanoparticles was therefore developed. Using first principles calculations, free energies due to changing OH coverage in the oxygen reduction reaction were predicted as functions of electrode potential and local surface structure. Free energy contour plots that considered surface OH coverage were developed. Therefrom, we theoretically predicted the optimum range of operating potentials, yielding design guidelines for catalytic surfaces.