Pt is widely used as a co-catalyst in TiO2 photocatalysis, since it greatly reduces the possibility of electron–hole recombination and enhances the hydrogen evolution during photocatalytic water splitting. Because of this important role, it is interesting to explore how supported Pt affects the structure of interfacial water on aqueous TiO2. We investigated the interface of water with Pt/TiO2 by first principles molecular dynamics simulations, focusing on single Pt atoms adsorbed on or doped into the prototypical anatase TiO2 (101) surface. As found for the aqueous interface with the pristine anatase surface, interfacial water remains intact in the presence of Pt adatoms. In contrast, water dissociation is observed when Pt substitutes either a surface Ti or a surface Oxygen atom. This difference originates from the different charge states of Pt in the different configurations, and highlights the key role of surface charge in the dissociation of interfacial water.

Structure of interfacial water on aqueous Pt/TiO2

2019 Fall National Meeting

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