A computational study on Pt/Co core−shell nanoparticles, which are promising candidates in the search of more active catalysts for the oxygen reduction reaction in fuel cell technology, is presented. We study the energetics of the segregation process using density functional theory (DFT) and a 37-atom cluster model. The influence of the adsorbates CO, O and O 2 on the segregation energy is investigated. Furthermore, Nørskov's model of the oxygen binding energy is used as an indicator to estimate the activity of the model system and to investigate electronic and geometric effects.

High level ab initio calculations were undertaken on the CH 2 OO anion and neutral species to predict the electron affinity and anion photoelectron spectrum. The electron affinity of CH 2 OO, 0.567 eV, and barrier height for dissociation of CH 2 OO -to O -and CH 2 O, 16.5 kJ mol −1 , are obtained by means of the W3-F12 thermochemical protocol. Two major geometric differences between the anion and neutral, being the dihedral angle of the terminal hydrogen atoms with respect to C−O−O plane, and the O−O bond length, are reflected in the predicted spectrum as pronounced vibrational progressions.

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Anion photoelectron spectra are reported for the iodide-carbon monoxide clusters, with supporting ab initio calculations for the 1:1 dimer anion and neutral complexes. A C(s) minimum geometry is predicted for the anion complex, while for the neutral complex two linear van der Waals minima are predicted differing in the attachment point of the iodine, that is, I···CO and I···OC. The predicted adiabatic photodetachment energy agrees well with the experimental spectrum. The photoelectron spectra feature a vibrational progression in the CO stretching mode, which becomes more pronounced for the larger clusters.