Influence of Au and TiO2 structures on hydrogen dissociation over TiO2/Au(100)

We performed H₂–D₂ exchange reactions over TiO_x/Au(100) and compared the observed reaction kinetics with those reported for TiO_x/Au(111) in order to clarify the influence of the Au and TiO₂ structures on dissociation of H₂ molecules. Low energy electron diffraction observations showed that the TiO₂ produced on Au(100) was disordered, in contrast to the comparatively ordered TiO₂ structure formed on Au(111). The activation energies and the turnover frequencies for HD formation over TiO₂/Au(100) agreed well with those for TiO₂/Au(111), clearly indicating that the hydrogen dissociation sites created over TiO₂/Au(100) were the perimeter interface between stoichiometric TiO₂ and Au, as was previously concluded for TiO₂/Au(111). We concluded that the creation of active sites for hydrogen dissociation was independent of the Au and TiO₂ structures consisting perimeter interface, and that local bonds that formed between Au and O atoms of stoichiometric TiO₂ were essential for the creation of active sites.