Effects of Electronic Structure Modifications on the Adsorption of Oxygen Reduction Reaction Intermediates on Model Pt(111)-Alloy Surfaces

In this work, the relationship between electronic structure and adsorption energies of oxygen reduction reaction (ORR) intermediates (O, OH, OOH, O2, and H2O) is investigated for modified Pt surfaces. Model surfaces were constructed to examine lattice strain and electronic ligand effects. Compressive strain, which broadens the metal d band, was found to destabilize adsorption of all of the intermediates. Whereas binding energy shifts due to strain correlate well for all of the intermediates examined, shifts in O adsorption energy resulting from ligand contributions were found not to correlate with the other intermediates. Additionally, the adsorption energy of oxygenate intermediates was found not to depend solely on the d-band center of the surface. Although the d-band center is important, adsorption is also dependent on the electron density near the Fermi level.