Structural and dynamical properties of water adsorption on PtO 2 (001).

The structural, dynamical and electronic properties of water molecules on the β-PtO 2 (001) surface has been studied using first-principles calculations. For both water monomer and monolayer, the adsorption energies are found to be three to five times larger than that of water adsorption on the Pt surface, and the dissociative adsorption configurations are energetically more stable. The adsorption energies are positively correlated with the charge transfer between the water molecule and the substrate, and the charge-rebalance between the Pt and O atoms of β-PtO 2 upon water adsorption. More interestingly, an exceptionally large redshift is observed in the OH stretching mode of the adsorbed water monomer, due to the very strong hydrogen bonding with the substrate. The strong water-substrate interactions have significant effects on the molecular orbitals of the chemisorbed water molecules.