Adsorption and dissociation of H2O2 on Pt and Pt-alloy clusters and surfaces.

The adsorption of H(2)O(2) on Pt and Pt-M alloys, where M is Cr, Co, or Ni, is investigated using density functional theory. Binding energies calculated with a hybrid DFT functional (B3PW91) are in the range of -0.71 to -0.88 eV for H(2)O(2) adsorbed with one of the oxygen atoms on top Pt positions of Pt(3), Pt(2)M, and PtM(2), and enhanced values in the range of -0.81 to -1.09 eV are found on top Ni and Co sites of the Pt(2)M clusters. Adsorption on top sites of Pt(10) yields a weaker binding of -0.48 eV, whereas on periodic Pt(111) and Pt(3)Co(111) surfaces, H(2)O(2) generally dissociates into two OH radicals. On the other hand, attempts to attach H(2)O(2) on bridge sites cause spontaneous dissociation of H(2)O(2) into two adsorbed OH radicals, suggesting that stable adsorptions on bridge sites are not possible for any of the clusters or extended surfaces that are being studied. We also found that the water-H(2)O(2) interaction reduces the strength of the adsorption of H(2)O(2) on these clusters and surfaces.